study the performance of turbo- expander (expander) · · 2016-12-14kasdi merbah university...

KASDI MERBAH UNIVERSITY OUARGLA

FACULTY OF APPLIED SCIENCES

PROCESS ENGINEERING DEPARTMENT

Dissertation

Presented to obtain a diploma of

MASTER

Specialty: Process Engineering

Option: Environmental Engineering

Presented by

CHOUIHA Hicham

MANSOURI Abd Elmalek

Theme

Publicly supported on: 30 /05/2016

In front of the jury:

ACADEMIC YEAR: 2015/2016

Ms. Ghedamsi Rebha Kasdi Merbah University Ouargla President

Mr. Achi Fethi Kasdi Merbah University Ouargla Examiner

Dr. Kahoul Fares Kasdi Merbah University Ouargla Examiner

Pr. Sakhri Lakhdar Kasdi Merbah University Ouargla Mentor

Study the Performance of Turbo-

Expander (Expander)

I

Acknowledgements

We would like to extend our thanks to our supervisor, Prof.

SAKHRI lakhdar. We would also like to thank Mr. MANSOURI Abd

Elali for helping us to pursue our Master’s research and to the present

jury for their appreciated evaluation. To all the staff of the Chemistry

Department and our sincere thanks will be to our families who stood

by our side till the end of this work.

I would like to acknowledge the support provided by

Mr.MANSOURI Abd elmalak my colleague at work, and to thank all

the staff, without you, this work would never have been finished.

Thank you!

Finally, we leave you with these immortal words, and wish all the

best for the rest of my colleague students.

“A man would do nothing if he waited until he could do it so well

that no one would find fault with what he has done”. [John Henry

Newman]

II

List of Table

Table Title Page

I-1-3-1 Gassi Touil main fields 4

I-3-1 The exploited field of GTL area 7

I-3-2 Composition of GTL raw gas by stream line 10

III-1 Some gas producers in the world (2010-2013) 45

III-2 Specifications of commercial gas 56

III-3 Uses of Liquefied Petroleum Gas in France and worldwide 61

III-4 Characteristics of Liquefied Petroleum Gas components 64

IV-7-3-1 Calculations in Expander side 74

IV-7-3-2 Calculation of 75

IV-7-3-3 Calculation of 75

IV-7-3-4 Calculating enthalpy, entropy inlet turbo-expander 76

IV-7-3-5 Enthalpy, Entropy calculations, output expander gas phase 76

IV-7-3-6 Enthalpy, Entropy calculations output expander liquid phase 77

IV-7-3-7 Actual calculation of Enthalpy, Entropy output expander gas phase 78

IV-7-3-8 Actual calculation of Enthalpy, Entropy output expander Liquid

Phase 78

III

List of Figure

Figure Title Page

I-1 Geographical situation of GTL Area 2

I-2 Carte of exploitation blocs 3

I-3 Location of different exploited fields 4

I-4 Plans production facilities of G-T-L 5

I-5 General Plan of CPF 9

I-6 Admission system and gas separation LP 11

I-7 Unit G01: Admission system and gas separation HP 12

I-8 System 470: water treatment 13

I-9 Unit G05: Booster compressor floor 14

I-10 Unit G05: Booster compressor floor 15

I-11 Unit G11: Unit of gas conditioning 17

I-12 Unit G11: Unit of gas dehydration 18

I-13 Unit G11: LPG recovery (Cryogenic) 19

I-14 Unit G11: LPG recovery (deethanizor) 20

I-15 Unit G50: residual gas compressor 21

I-16 Unit P10: unit of condensate stabilization 22

I-17 Unit P10: unit of condensate stabilization/debutanization 23

I-18 The LPG storage spheres on-spec/ off-spec 24

I-19 Reservoirs of condensate storage on-spec/off-spec 25

I-20 Unit 36V & 16V: gas metering and gas shipping Sewer 26

I-21 The generale plan of CPF unit 27

II-1 Turbo-Expander magnetic bearings CPF GT 28

II-2 Overview of Turbo-Expander 29

II-3 Turbo-expander Image 30

II-4 The different parts of Turbo-Expander 31

II-5 The detailed diagram of the Turbo-Expander 32

II-6 The detailed diagram of the Joule Thompson valve 38

III-1 Distribution of natural gas reserves in the world 42

III

III-2 Evolution of reserves of conventional natural gas (1980-2013) 43

III-3 Natural gas production capacity in the world (%) 44

III-4 The Algerian gas export routes 49

III-5 Regional demand outlook 52

III-6 Breakdown of the uses of gas in 2004 to 2020 55

IV-1 Diagram H-S side Expander 71

Abbreviation

IV

T.E: Turbo-Expander

J.T: Joule Thomson

G11-VA-32-201: Two-phase separator tank

G11-CA-32-201: Absorber

G11-GA-32-201: Interchange gas/gas

G11-GA-32-202: Interchange gas/liquid

G11-CC-32-201: Rectifying column (deethanizer)

P10-CC-21-101: Rectifying column (debutanizer)

G11-KH-32-201: Le Turbo-Expander

GTL: Gassi Touil Location

CPF: Central Production Facilities

MEG: Monoethylene glycol

LPG: Liquefied Petroleum Gas

LNG: Liquefied Natural Gas

LP: Low Pressure

HP: High Pressure

NOTATION

V

F : force N

P : pressure Kg/ cm2

V : speed m/s

A : section mm2

Q : volume flow m3/ h

m : mass flow kg /s

ρ : volume mass kg / m3

D : diameter mm

π : constante 3.14

H : enthalpy kj/ kg

S : entropy kj/ kg k

W : work Kj / Kg

MMSCMD : Million Metric Standard Cubic Meters per Day

VI

Summary Acknowledgements I

List of Table II

List of Figure III

Abbreviation IV

Notation V

Summary VI

Introduction 1

Chapter I Presentation of Gassi Touil Region

I Presentation of GTL Production Area 2

I.1 Gas Treatment and Processing General Description (GTL – CPF) 2

I.1.1 Geographical Location 2

I.1.2 Historical background of Gassi Touil field 3

I.1.3 Gassi Touil Fields 4

I.1.4 The Production Centers of Gassi Touil 5

I.2 The Production Center (OLD INSTALLATION) 5

I.2.a Oil treatment unit 6

I.2.b Gas treatment units 6

I.2.c Associated Gas recovery and reinjection Unit (URGA) 6

I.2.d Industrial water treatment unit (déshuilage) 6

I.3 Gas Processing Plant CPF 7

I.4 General Description of Process CPF GTL 10

I.5 Description of System and Gas Circulation 11

I.5.a Unit G01: admission system (LP, HP) 11

I.5.b Unit G05: Booster Compressors 13

I.5.c Unit G11: Gas conditioning 16

I.5.d Unit G11: Gas dehydration 17

I.5.e Unit G11: LPG Recovery (Cryogenic process) 18

I.5.f Unit G11: LPG Recovery (deethanizer) 19

I.5.g Unit G50: Residue Gas Compression 20

I.5.h Unit P10: Condensate stabilization 21

I.5.i LPG Storage 23

VI

I.5.j Condensate Storage 24

I.5.k Gas Export and Metering 25

I.5.l Utilities of process inside CPF 26

Chapter II Description of Turbo-expander

II.1 Introduction 28

II.2 General Description of TURBO-EXPANDER 29

II.2.1 Application 29

II.2.2 Main Characteristics 30

II.2.3 Role of New Turbo-Expander has magnetic bearings in the unit 30

II.3 Description of Parts and Main Functions of the Machine 31

II.3.1 Parts of the machine 31

II.3.2 Main functions of the machine 32

II.3.2.1 Compression function 32

II.3.2.2 Guiding function of the rotor 32

II.4 Sealing System Description of TURBO-EXPANDER 33

II.4.1 Seal gas system 33

II.5 Active Magnetic Bearings 33

II.5.1 Bearings 34

II.6 Factors Negatively Affecting The Wealth 34

II.7 Precautions and Recommendations on The TURBO-EXPANDER 35

II.7.1 Cleanliness 35

II.7.2 Pressure Tests 35

II.7.3 Effects of Methanol and Glycol to magnetic bearings 36

II.7.4 Procedure prior to the start 36

II.7.4.1 Control 36

II.7.4.2 Anti-pumping valve 37

II.7.4.3 Pneumatic systems 37

II.7.4.4 Thrust balancing system 37

II.8 Advantages and Disadvantages of TURBO EXPANDER 37

II.8.1 Advantage 37

II.8.2 Disadvantages 38

II.9 Description Valve JOULE-THOMPSON (JT) 38

II.9.1 Description 38

VI

II.9.2 Operating principle 39

II.10 Advantages and Disadvantages of Using the Valve JOULE-

THOMPSON (JT) 39

II.10.1 Advantage 39

II.10.2 Disadvantages 39

II.11 Conclusion 40

Chapter III Treatment Of Natural Gas

III.1 Natural Gas 41

III.1.1 Introduction 41

III.1.2 Natural Gas Reserves in the World 41

III.1.3 Evolution of reserves of conventional natural gas 42

III.1.4 The gas production in the world 43

III.1.5 Consumption of Natural Gas in the World 48

III.1.6 The Gas in Algeria 48

III.1.7 Outlook 49

III.1.8 Characteristics of Natural Gas 52

III.1.8.1 Density 52

III.1.8.2 Calorific value 52

III.1.8.3 Chemical composition 53

III.1.9 The different types of Natural Gas 53

III.1.10 Utilization 54

III.1.11 Processing of Natural Gas 55

III.1.12 Specification of the treated gas 56

III.2 Liquefied Petroleum Gas (LPG) 57

III.2.1 LPG in the world 58

III.2.2 LPG in Algeria 58

III.2.3 Algerian exports of the LPG 59

III.2.4 Use of the LPG 59

III.2.5 Characteristics of LPG 62

III.2.6 LPG specifications Gassi Touil (CPF) 63

III.3 The Condensate 65

III.3.1 Generality 65

III.3.2 Properties of the Condensate 65

VI

Chapter IV Thermodynamic study

IV Introduction 68

IV.1 Definitions 68

IV.2 Concept on the Relaxation 68

IV.3 Of Thermodynamics 68

IV.3.1 First law of Thermodynamics 68

IV.4 Relaxing with Production Work (TURBO-EXPANDER) G11-KH-

32-201 69

IV.5 Thermodynamic 69

IV.5.1 First law of Thermodynamics 69

IV.5.2 The specific heat of a gas mixture 69

IV.5.3 The molecular weight of a gas mixture 70

IV.5.4 The isentropic exponent 70

IV.5.5 The specific gas constant 70

IV.5.6 Compressibility factor Z 70

IV.6 Works Relaxation 72

IV.7 Method of Calculating the Efficiency of the Turbine 72

IV.7.1 Calculation of enthalpy and entropy at the entrance of the expander

and 73

IV.7.2 Calculating enthalpy, entropy discharge the output expander and

74

IV.7.3 The Actual Work of Relaxation 74

IV.8 Interpretation of Results 81

Conclusion 82

Bibliographic

Introduction

1

Introduction

Hydrocarbons are the most strategic wealth in the world; because are the motor industry and this

is why their consequences and influences are important at all levels.

The demand for natural gas comes in second place after oil, but its importance is increasing

because it is a clean energy source which does not affect the environment.

Today Sonatrach ensures the strategic missions focused on the research, production,

transportation, processing and liquefaction of natural gas, Liquefied Petroleum Gas separation and

supplying the domestic market and commercialization of liquid and gaseous hydrocarbons the

international market.

The Production division (DP) is one very important structure in Sonatrach. It operates in all the

fields of oil and gas. Regional management GTL is a DP structure, which performs development

projects, operations and raw processing field.

The first objective in Gassi Touil factory is to ensure better recovery of condensate ( or more) what

justifies the importance of using the Turbo-Expander.

To achieve lower temperatures. The TURBO-EXPANDER is widely used in gas treatment

facilities; they are indispensable in the various processes; are of considerable reliability and have

good performance and importance in the circuit of gas (separation, liquefaction…).

CHAPTER I

Presentation of

Gassi Touil

Region


2

I. PRESENTATION OF GTL PRODUCTION AREA:

I.1. Gas Treatment and Processing General Description (GTL – CPF):

I.1.1. Geographical location:

Gassi Touil is a Sonatrach oil and gas production area. It is with In-Amenas among the

oldest discovered field in Algeria. The production equipment was installed in the 60th of last

century.

The area situated in the south east of Algeria, about 1000 Km from Algiers and about 150

km from Hassi Messaoud. It administratively belongs to the Wilaya of Ouargla and goes on

170 km of length and about 105 km of width. Figure 1 shows the location of GTL area. [7]

Figure (I-1): Geographical situation of GTL Area.


3

The Algerian territory is divided in many blocs. Those different blocs are explored or

exploited either with Sonatrach alone or in join venture with international partners. The

majority of GTL fields are located within bloc # 246. The bellow carte shows this bloc and its

voisinated blocs.

Figure (I-2): Carte of exploitation blocs

I.1.2. Historical background of Gassi Touil field:

The field of Gassi Touil was discovered in 1961 after the drilling of GTLL1, this

exploration well showed the presence of gas in the reservoir Trias superior & inferior and it

was until the drilling of GTLL3, to discover the presence of oil in the Trias inferior at a depth

of 2100 m.

The drilling of GTLL4 showed also that the Trias intermediate contains oil at depths of 2020

- 2037 m.


4

The development of this field continued rapidly, during the next two years about 30 wells

were drilled and put in exploitation. The exploration and drilling took place until 1974 in order

to delineate the contours of the field. [6]

I.1.3. Gassi Touil Fields:

The area of production of Gassi Touil is composed of many fields in which the main are:

Table (I-1-3-1): Gassi Touil main fields.

Field

Number of wells

Discovered Oil Gas Total

Nezla 31 08 39 1958

Brides × 06 06 1958

Toual 01 09 10 1958

Hassi Touareg × × 00 1959

Gassi Touil 67 11 78 1961

Hassi Chergui × 14 14 1962

Gassi El Adem × 04 04 1967

Rhourde El Khlef × 03 03 1959

Total x X 187 ×

The following satellite figure shows the different fields of GTL and their locations:

Figure (I-3): location of different exploited fields.


5

I.1.4. The production centers of Gassi Touil:

The area of Gassi Touil possesses installations to treat oil and gas. They are as follow:

The old center of production CP (oil treatment).

Center of production/processing facilities CPF (Gas processing plant).

I.2. THE PRODUCTION CENTER (OLD INSTALLATION):

The plant CP of Gassi Touil was put in production in 1965. The total area of the field is

about 120 with 60 productive wells, 6 injecting wells and 11 dry or abundant wells.

The map below locates the main processing facilities on the site Gassi Touil.

Figure (I-4): Plans production facilities of G-T-L.

Description of central production :

The whole quantity of produced oil in Gassi Touil is sent towards the center of production

CP in order to be treated and stabilized. The center is composed of the following sub-unites:

Oil treatment and stabilization unit;

Gas treatment unit.

Associated gas reinjection unit (URGA).

Industrial water treatment unit (déshuilage);


6

Utilities (Power generation, service and instrument air)

Fire prevention system.

Infrastructures (safety buildings, MCB, maintenance workshop). [1]

a) Oil treatment unit:

Oil treatment and stabilization unit is composed of separation batteries that can handle

HP and MP flow rates coming from different fields. The installed capacity is about 21 850

/d.

Beside that a storage tanks are provided with a total installed capacity of 75 400 .

The sales product is export to DTR HEH via a pumping system that can deliver 1250

/h.

b) Gas treatment units:

Four small units are installed in order to recover the LNG, based on the expansion via a

turbo- expander that lowering temperature to a suitable value for the duty. The units actually

are stopped and the handled gas is sent to the new plant CPF.

c) Associated Gas recovery and reinjection Unit (URGA):

This new unit of centrifugal compressors aimed to replace the old infrastructure of

reinjection. It collects about 4,9 MMSCMD of gas coming from the different batteries of

separation and the stopped gas treatment unit. The gas is compressed up to 152 Bars and re-

injected in specified wells to maintain the pressure of the reservoir. [2]

d) Industrial water treatment unit (déshuilage):

This unit has an object to treat produced water from separation sections. The water may

contains hydrocarbons, solid particules and in suspension particules MES. The unit can treat

up to 100 /h of water. The hydrocarbons content in treated water should be less than 5%

volume basis. [2]

Utilities :

1. Fuel Gas unit:

The aim of this unit is to provide the necessary Fuel gas to different users (GT 5002),

(Sealing gas for LP compressor, feeding LP/HP flares). The gas in this unit is firstly

separated from HC liquids that may existed, then preheated and cleaned through mesh

filters. The flow rate of fuel gas is 200 000 /d at 18.5 bar.


7

2. Air production unit:

This unit is designed as a package that provides all necessary controles and commands of

operation. It is placed to produce:

Instrument air (dry / clean) at 12 bar.

Utility air (service) at 12,5 bar.

I.3. GAS PROCESSING PLANT CPF:

SONATRACH wishes to exploit its different fields of GTL in a preferment way. For this,

it has to treat and process the gathered raw gases in order to produce sales gases, LPG and

condensates that reply to all client requirements and international norms.

The surface equipment installed in CPF Gassi Touil permits the gathering, treatment,

processing and export of final products up to 12 MMCMD as a dry gas basis, coming from

54 wells in which 30 wells are already existed.[3]

The gathering system is composed of producing lines from wells to in site manifolds and

then collected in main gathering lines to CPF according to their operating pressures. We

distinguish LP trunk lines (GT+ HTG) and HP trunk lines (REK+NZ+TL).

Table (I-3-1): The exploited fields of GTL area.

Field Number of wells Wells in service

HASSI TOUAREG 9 3

RHOUDE EL KHELF 3 2

GASSI TOUIL 11 8

NEZLA 8 3

GASSI EL ADEM 2 2

BRIDES 8 1

TOUAL 13 3

TOTAL 54 22


8

The center of production (CPF - Central Processing Facilities) is designed to treat a

nominal flow rate of 12 MMCMD as a dry gas basis and it consists of the following main

units:

Inlet facilities G01.

Inlet facilities G01.

Condensate stabilization unit P10.

Residue Gas compression unit G50.

The off-site installations are the following:

Pumping, export and metering facilities.

LPG and condensate storage unit.

Flare system.

CPF utilities and chemical requirement unit.

Buildings. [1]

Different units of CPF:

Unit G01: Inlet facilities and chemical injection.

Unit G05: Booster compression Trains.

Unit G11: LPG recovery.

Unit G50: Residual gas compression.

Unit P10: Condensate stabilization.

Unit 36V & 16V: Gas metering and export pipeline. [7]


9

Figure (I-5) : General Plan of CPF.


10

Table (I-3-2): Composition of G.T.L raw gas by stream line.

Component

Mole fraction (% mole)

LP(HTG) LP(GT) HP

0.00883 0.08241 0.01581

0.00369 0.00175 0.01122

C1 0.84252 0.68978 0.77690

C2 0.06018 0.10219 0.07541

C3 0.02514 0.04350 0.02882

iC4 0.00592 0.01440 0.00628

nC4 0.00864 0.001440 0.00889

iC5 0.00446 0.00596 0.00436

nC5 0.00291 0.00490 0.00323

C6 0.00466 0.00911 0.00453

C7 0.00087 0.00197 0.00858

C8 0.00068 0.00173 0.00284

C9 0.00049 0.00088 0.00284

C10 0.00039 0.00075 0.00138

C11 0.00107 0.00073 0.00828

0.02955 0.02992 0.04176

∑ 1.00000 1.00000 1.00000

I.4. GENERAL DESCRIPTION OF PROCESS CPF GTL:

The plant Center of Production Facilities (CPF) is mainly designed to treat and process 12

MMSCMD as dry gas basis in order to produce sales Gas, LPG and condensate that satisfy

requirements and specifications. The plant can operate normally at a flow rate comprises

between 30% (3.6 MMSCMD) and 110% (13.2 MMSCMD). The availability of the plant is

94.5% (345day/year).[3]


11

I.5 DESCRIPTION OF SYSTEM AND GAS CIRCULATION:

a) Unit G01: admission system (LP, HP):

The inlet facility of CPF receives the production fluid (LP and HP) based on the pressure of

the wells (PHP=70-73 bar; PLP=29-35 bar). The purpose of slug Catcher is to receive the

anticipated gas/liquid volumes from the trunk lines and separate into the gas, hydrocarbon

liquid and water at inlet of the CPF and protect the downstream processing facilities from any

potential upsets caused by upstream conditions. Wet gas with produced water coming from

Hassi Touareg Field HT and Gassi Touil Field GT is gathered and received at finger type LP

Slug Catcher (G01-VL-20-101).

Gas from the LP Slug Catcher is sent to the Booster Compressor (G05) and Hydrocarbon

condensate separated in the LP Slug Catcher is sent to LP Slug Catcher Condensate Flash

Drum (G01-VD-20-101). Recovered hydrocarbon condensate is pumped to HP Condensate

Flash Drum (G01-VD-20-201) .Off gas and produced water are sent to LP fuel gas system and

Produced Water Flash Drum (G01-VL-20-102) respectively.

Figure (I-6) Unit G01: Admission system and gas separation LP.

Wet gas coming from Toual, Rhourde el Khlef Field REK, Nezla NZ, Gassi el-Adem Field

GEA and Brides BR fields are gathered and received at finger type HP Slug Catcher (G01-VL-


12

20-201).The gas streams from HP Slug Catcher (G01-VL-20-201) and LP Slug Catcher (G01-

VL-20-101) through Booster Compressor (G05) are combined and fed into the LPG Recovery

Unit (G11).

Hydrocarbon condensate separated in the HP Slug Catcher together with hydrocarbon

condensate from LP Flash Drum (G01-VD-20-101) is sent to HP Condensate Flash Drum (G01-

VD-20-201). Recovered hydrocarbon condensate is pumped to Condensate Stabilization Unit

(P10) through HP Slug Catcher Condensate Pump (G01-PA-20-201A/B/C). After passing through

the Condensate Feed Filter (G01-VJ-20-201A/B) and Condensate Feed Coalescer (G01-VJ-20-

202). Off gas and produced water are sent to Booster Compressor (G05) and Produced Water

Flash Drum (G01-VL-20-102) respectively. [7]

Figure (I-7) Unit G01: Admission system and gas separation HP.

Produced water from the LP Slug Catcher, LP Slug Catcher condensate flash drum, HP Slug

Catcher, HP Slug Catcher condensate flash drum and Condensate feed coalescer is sent to

Produced Water Flash Drum (G01-VL-20-102). Received produced water is sent to a CPI

separator (470-UX-44-101) While off-gas is sent to common flare. The condensate accumulation

on the produced water surface makes the discrepancy between the level measured by 20-LIT-


13

1014 (Differential pressure type) and the level measured by 20-LIT-1012 (Radar type) and the

discrepancy alarm initiate in the MCR. Then operator should check the interface level with 20-

LG-1013 and skimming the accumulated condensate as per following, if required.

Figure (I-8): System 470 water treatment.

b) Unit G05: Booster Compressors:

Gas from LP Slug Catcher (G01-VL-20-101), HP Slug Catcher Condensate Flash Drum

(G01-VD-20-201) and Stabilizer (P10-CB-21-101) overhead shall be sent to 1st Stage Suction

K.O Drum (G05-VD-23-101A/B). Liquid from the 1st stage suction K.O drum is planned to be

returned to the LP Slug Catcher Condensate Flash Drum (G01-VD-20-101) along with 2nd

stage suction and discharge K.O drums.

Compressed gas shall be cooled down to 60 °C by the Booster Compressor 1st Stage

Discharge Cooler (G05-GC-23-101A/B). 2nd Stage Booster Compressor (G05-KA-23-102A),

which is a constant speed motor driven centrifugal type, compress the gas from 2nd stage

suction K.O drum (G05-VD-23-102A/B) up to 71,0 bars. Compressed gas is cooled down to

60 by Booster Compressor 2nd Stage Discharge Cooler (G05-GC-23-102A/B) which has a


14

fixed motor. Then the cooled compressed gas is sent to the LPG Recovery Unit (G11) through

Stage Discharge K.O. Drum (G05-VD-23-103A/B).

Condensed liquid from Stage Suction K.O Drum and Discharge K.O. Drum is combined

with condensate liquid from 1st Stage Suction K.O Drum and returned to LP Slug Catcher

Condensate Flash Drum (G01-VD-20-101).

Figure (I-9) Unit G05: Booster compressor floor.


15

Figure (I-10) Unit G05: Booster compressor floor.


16

c) Unit G11: Gas conditioning:

The combined gas streams from HP Slug Catcher (G01) and Booster Compressor (G05) pass

through Deethanizer Side Reboiler (G11-GA-32-205) tube side where its temperature is

reduced. Wet gas / Residue gas heat exchanger (G11-GA-32-206) is also provided in parallel

with Deethanizer Side Reboiler (G11-GA-32-205) to reduce dehydrator inlet temperature. The

gas then enters the Dehydrator Feed Gas Separator (G11-VA-24-101).

A recycle line is provided from the Residue Gas Cooler (G50-GC-27-101A/B) outlet to the

Inlet of Deethanizer Side Reboiler (G11-GA-32-205) for Startup, turndown and dehydrator

regeneration gas back-up operation. Design flow rate for this line is 30% of nominal flow rate

for LPG recovery unit. Condensate collected in Dehydrator Feed Gas Separator (G11-VA-24-

101) is sent to HP Slug Catcher Condensate Flash Drum (G01-VD-20-201). Gas from the Feed

Gas Separator (G11-VA-24-101) is sent to Mercury Adsorber (G11-VW-24-101). The purpose

of the mercury adsorber is to reduce Hg concentration in process gas from 10,000 ng/N in

feed to less than 10 ng/N in outlet gas to the downstream system. Mercury removal protects

the Expander (G11-KH-32-201) and Expander Compressor (G11-KA-32-201) impeller (which

are made of aluminium) against corrosion.

Gas from the mercury adsorber enters the Dehydrator Feed Gas Filter/ Coalescer (G11-VJ-

24-101). Liquid collected in Dehydrator Feed Gas Filter/ Coalescer (G11-VJ-24-101) is sent to

HP Slug Catcher Condensate Flash Drum (G01-VD-20-201). [7]


17

Figure (I-11) Unit G11: Unit of gas conditioning.

d) Unit G11: Gas dehydration:

Gas after passing through Dehydrator Feed Gas Filter/ Coalescer (G11-VJ-24-101) enters

two out of the three Gas Dehydrators (G11-VK-24-101A/B/C). The dehydration system is

designed to remove water from the gas to less than 0.1 ppm by means of molecular sieve bed

dehydrators, preventing hydrates formation in the cold section of the process.

The control logic for the dehydration process is set so that two dehydrators are adsorbing

while one is in regeneration cycle.

Once dehydrated, the gas passes through Dehydrated Gas Dust Filter (G11-VJ-24-102A/B)

which collects any fines that may come from the dehydrators. If not filtered, this dust could

cause plugging in downstream equipment. One filter is in service while the other is spare.

The regeneration gas flow through regeneration circuit is attained by means of Regeneration

Gas Compressor (G11-KA-24-101). After the gas is compressed, it is heated (using hot oil as

the heating media) in Regeneration Gas heater (G11-GA-24-101A/B/C) reaching the

temperature required to vaporize the moisture from the water saturated sieves. The hot

regeneration gas flows upward through the dryers desorbing the water. The regeneration gas is

cooled in fin fan Regeneration Gas Cooler (G11-GC-24-101), where water is condensed and

separated in Regeneration Gas Water Separator (G11-VD-24-101). Gas from Regeneration Gas

Water Separator (G11-VD-24-101) enters the tube side of Deethanizer Side Reboiler (G11-GA-


18

32-205) along with combined gas streams of G01 and G05. Whereas, liquid collected in

Regeneration Gas Water Separator (G11-VD-24-101) is sent to HP Slug Catcher Condensate

Flash Drum (G01-VD-20-201).

Figure (I-12) Unit G11: Unit of gas dehydration.

e) Unit G11: LPG Recovery (Cryogenic process):

After the inlet gas has been dehydrated, a part of it enters the tube side of Feed Gas/ Cold

Residue Gas Heat Exchanger (G11-GA-32-201A/B) where it is cooled in cross exchange

with cool residue gas coming from the tube side of Deethanizer O/H Condenser (G11-GA-

32-203) while the remaining part is cooled in the tube side of Feed Gas/ Feed Separator

Liquid Heat Exchanger (G11-GA-32-202A/B). The gas then enters the Expander Feed

Separator (G11-VA-32-201) which provides separation of the liquid condensed from the feed

gas during cooling.


19

Figure (I-13) Unit G11: LPG recovery (Cryogenic).

The liquid removed in the Expander Feed Separator (G11-VA-32-201) is flashed on level

control to the shell side of Feed Gas/ Feed Separator Liquid Heat Exchanger (G11-GA-32-

202A/B) where it provides cooling to the remaining part of inlet gas stream before feeding the

Deethanizer (G11-CC-32-201) at its lowest mid-column feed position. The vapors leave the

Expander Feed Separator (G11-VA-32-201) through a vane pack and flows to Expander (G11-

KH-32-201). In Expander, the gas expansion results in cooling of the stream and also work

extracted is used for running Expander Compressor (G11-KA-32-201). The Expander discharge

stream then flows to Absorber (G11-CA-32-201) column as feed near the bottom.

f) Unit G11: LPG Recovery (deethanizer):

The liquid at Absorber (G11-CA-32-201) bottom is sent to the top of Deethanizer (G11-CC-

32-201) as reflux; this reflux liquid condenses propane and heavier hydrocarbons from the

vapors leaving the Deethanizer overhead. The overhead vapor stream coming out of the

Deethanizer (G11-CC-32-201) is cooled and partially condensed in the shell side of Deethanizer

O/H Condenser (G11-GA-32-203), by cross-exchange with the cold Absorber (G11-CA-32-201)

overhead gas and then fed to the Absorber as reflux, this reflux liquid condenses propane and

heavier hydrocarbons coming up the Absorber column, thereby increasing the concentration of

ethane in the overhead gas. The overhead gas temperature is also reduced due to heat of

absorption effect. In the lower section of the Deethanizer (G11-CC-32-201) hot vapors

generated by Deethanizer Reboiler (G11-GA-32-204) and Deethanizer Side Reboiler (G11-GA-

32-205) strip the ethane and lighter components from the liquid flowing down the column.

Sufficient stripping vapor is generated to maintain the C2/C3 molar ratio.


20

The temperature of vapors from Deethanizer Reboiler (G11-GA-32-204) is adjusted by means

of hot oil circulation through the Deethanizer Reboiler. The bottom LPG rich stream is sent by

level control to Condensate Stabilizer/Debutanizer Unit (P10).

Figure (I-14) Unit G11: LPG recovery (deethanizor).

g) Unit G50: Residue Gas Compression:

At the absorber top the residue gas ensures first the cooling and partial condensation of of the

vapor coming from deethenizer overhead (G11-GA-32-203), as previously described.

This unit consists of two identical process trains (Gas Turbine driven Residue Gas

Compressor: 2 x 50.

During the gas processing, the pressure is reduced to achieve products objectives and

therefore, in order to export the residual gas product, the pressure must be increased allowing

the gas to be transferred.

The Residue Gas Compressor (G50-KA-27-101A) type is centrifugal driven by a gas turbine

SGT400 (G50-DT-27-101A/B). Gas enters to Residue Gas Compressors Suction Scrubber

where any remaining liquid is separated. After compression stage (up to around 70.8 bar), the

gas is cooled. It shall be ensured that the temperature is below the maximum export gas

temperature downstream Residue Gas Cooler. The gas is then exported via the pipeline and, in


21

the case of low plant feed rates, a recycle line is provided from the Residue Gas Cooler (G50-

GC-27-101A/B) outlet to the Inlet of Deethanizer Side Reboiler (G11-GA-32-205) for Start Up,

turndown and dehydrator regeneration gas back-up operation. Design flow rate for this line is

30% of nominal flow rate for LPG recovery unit. Residue gas from Residue Gas Compressor

(G50-KA-27-101A) suction is normally sent to Fuel Gas System (410) where it is used as HP

fuel gas.

Figure (I-15): Unit G50: residual gas compressor.

h) Unit P10: Condensate stabilization:

Recovered hydrocarbon condensate from HP Slug Catcher Condensate Flash Drum (G01-

VD-20-201) is pumped to condensate stabilization unit (P10) using one HP Condensate flash

drum Pump (G01-PA-20-201A/B/C). The condensate passes through the Condensate Feed

Filter (G01-VJ-20-201A/B) and condensate Feed Coalescer (G01-VJ-20-202) before entering

P10 Unit.

The liquid feed is then passed through the shell side of Stabilizer Feed Pre-heater (P10-GA-

21-101A/B) where it is heated by condensate product from tube side of Debutanizer Feed

Preheater (P10-GA-21-103) and then fed to Stabilizer Column (P10-CB-21-101) to

eliminate light ends


22

The stabilizer OVHD gas from Stabilizer Column (P10-CB-21-101) is routed to the LP

Fuel Gas system (410) or sent to booster compressor area (G05) for recompression via 21-

PIC-1005 split range control. The stabilized liquid from Stabilizer Column (P10-CB-21-

101) bottom enters the top tray of the stripping section of Debutanizer (P10-CC-21-

101) as Feed. Also the recovered liquid from Deethanizer (G11-CC-32-201) bottom

in LPG Recovery Unit (G11) after passing through the shell side of Debutanizer Feed

Pre-heater (P10-GA-21-103) is fed to Debutanizer (P10-CC-21-101) to separate LPG and

condensate.

Figure (I-16) Unit P10: unit of condensate stabilization.


23

Figure (I-17) Unit P10: unit of condensate stabilization/debutanization.

i) LPG Storage:

On-specification LPG after passing through Debutanizer O.H. Condenser (P10-GC-21-101)

and Debutanizer O.H. Receiver (P10-VA-21-101) is pumped through Debutanizer Reflux Pump

(P10-PA-21-101A/B) to LPG on-specification Storage Spheres (31G-RD-33-101A/B). Off

specification LPG if produced due to any abnormal operation must be diverted to LPG off

specification storage sphere (39G-RD-33-101) through Debutanizer Reflux Pump (P10-PA-21-

101A/B). Off specification LPG is sent back to HP Slug Condensate Flash Drum (G01-VD-20-

201) for reprocessing. [7]


24

Figure (I-18): the LPG storage spheres on-spec/ off-spec.

j) Condensate Storage:

On specification Condensate is routed to Condensate Product Storage tanks (31C-RA-35-

101A/B) after passing through tube side of Debutanizer Feed Pre-heater (P10-GA-21-103), tube

side of Stabilizer Feed Pre-heater (P10-GA-21-101 A/B) and air fin fan cooler Condensate

Rundown Cooler (P10-GC-21-102). In case of Off-specification condensate production, it must

be diverted to Condensate off specification Tank (39C-RM-35-101).

Off specification Condensate is sent back to HP Slug Condensate Flash Drum (G01-VD-20-

201) for reprocessing.


25

Figure (I-19): reservoirs of condensate storage on-spec/off-spec.

k) Gas Export and Metering:

Residue gas from Residue gas cooler (G50-GC-27-101A/B) is routed to Metering Station for

Residue Gas (36V-JX-27-101) and then to Residue Gas Export Pipeline. Residue Gas Export

Pipeline consists of Pig Launcher for Residue Gas Export Pipeline (16V-VM-34-101) and Pig

Receiver for Residue Gas Export Pipeline (16V-VM-34-102). During start up Residue Gas from

the export pipeline is sent back to the Fuel Gas System (410) as a source and also to the Flare

system (800) as emergency backup for flare pilot and backup.[7]


26

Figure (I-20): Unit 36V & 16V: gas metering and gas shipping Sewer.

l) Utilities of process inside CPF:

The utilities are very important within the CPF in order to ensure the supply of all necessary

requirements for startup and normal operation. The main utilities are:

Unit 410: Fuel gas system, which has to satisfy the norms required by Gas turbine and

the heater.

Unit 420/430: Instrument and plant air system / inert gas system.

Unit 440: Diesel Fuel System.

Unit 460: Sanitary Water System.

Unit 470: Waste water treatment system.

Unit 480: Hot oil system which has to satisfy the requirement to operate the plant in

accordance to specifications (LPG recovery, condensate stabilization…).

Unit 800: Flare system and burn pit.

Unit 0C1: Closed/open drain system.

Unit 6P0/BID: Emergency diesel generators.

Unit 4A0/4P0: Utility water / potable water system

On average 300 hours / year. As they consume respectively 660 l / h and 118.6 l / h diesel,

total consumption is expected to reach 234 / year. [7]


27

Figure (I-21): THE GENERALE PLAN OF CPF UNIT.

CHAPTER II

Description of

Turbo-expander


28

DESCRIPTION OF THE TURBO-EXPANDER:

II.1. INTRODUCTION

The raw gas treatment process at the CPF unit Gassi Touil region in particular section

recovery of LPG called G11. One of the instruments that make up this unit is the new

expansion turbine or turbo-expander with magnetic bearings, saw its interest increase as

energy recovery turbine, and it is most certain types of designs facilities without this machine.

The success of its implementation is mainly due to its high efficiency and high reliability of

operation where the greater use of Turbo-Expander in industry is for condensation of gas

mixtures to recover the heavy fractions of such mixtures.

In this chapter we present the general operation of Turbo-Expander of magnetic bearings,

Figures (II.1) and (II.2) give an overview of the Turbo-Expander.

Figure (II-1): Turbo-Expander magnetic bearings CPF GT.


29

II.2. GENERAL DESCRIPTION OF TURBO-EXPANDER:

A turbo-expander or expansion turbine is a machine that converts the energy of a gas or

steam into mechanical work during its expansion in the turbine. This expansion is being very

quickly. This greatly reduces the amount of heat transferred to or received by the system, and

therefore in agreement with the first law of thermodynamics, the internal energy of the gas

decreases when it is relaxed which results in a large temperature drop that .This then makes

the Turbo-Expander a producing machine of the cold (in the refrigeration circuit) or

producing mechanical work in the power circuits. Figure (II.2) provides an overview of the

Turbo-Expander. [1]

Figure (II-2): Overview of Turbo-Expander.

II.2.1. Application:

Cryogenic:

Energy recovery on oil fields

Air separation and liquefaction ,

Purification of gas: , He

Methane recovery and LPG from natural gas

Liquefaction of natural gas. [6]


30

II.2.2. Main characteristics:

The reaction turbine has a radial inlet and axial exhaust.

Recovery is usually performed in a single expansion stage at high speed is between [10 to

50,000 r / min] for medium and high powers [45 70 000 r / min] for low power: <50 kW. Its

power range for oil installations ranges from [50-60000 kW], It has a good isentropic

efficiency:

From 80 to 86%, it decreases if the expansion ratio increases, with conservation of the

efficiency variable load by use of blades guiding movable to the inlet (possibility of variation

of load: 50 to 120% of nominal flow rate) and good tolerance to the presence of condensate

and solid particles, and an energy recovery favored by low inlet temperatures. [1]

II.2.3. Role of New Turbo-Expander has magnetic bearings in the unit:

The Turbo-Expander presented in Figure (II.3) functions to recover energy that occurs

when a high-pressure gas passes through the turbine to reduce the pressure (isentropic

expansion).

Figure (II-3): turbo-expander Image.


31

The expansion of the gas lowers the temperature below that obtained by the Joule-

Thomson effect so it can recover a large amount of liquid. This energy is intended to drive the

compressor to increase gas pressure before being sent as gas sales.

II.3. DESCRIPTION OF PARTS AND MAIN FUNCTIONS OF THE

MACHINE:

II.3.1. Parts of the machine:

As shown in Figure (II.4), the turbo-expander is mainly comprised of:

A turbine.

A compressor.

Circuit of seal gas.

A control panel.

Table signaling parameters.

Figure (II-4): The different parts of Turbo-Expander.


32

II.3.2. Main functions of the machine:

II.3.2.1. Compression function:

Gas enters the compressor through the suction tube and arrives via a distribution channel to

the first wheel. It then passes through a set of moving parts, the wheels and the fixed parts,

broadcasters and return channels. The gas is discharged to the output of the last diffuser in the

volute and the discharge connection.

II.3.2.2. Guiding function of the rotor:

The wheels are mounted on the shaft and together form the rotor to be guided rotatably and

axially. The axial compensation is automatically performed to all of the shaft speeds.

Figure (II-5): The detailed diagram of the Turbo-Expander.


33

II.4. SEALING SYSTEM DESCRIPTION OF TURBO-EXPANDER:

The Turbo-Expander is designed for relaxation and compression of natural gas, it consists

of a Turbo-Expander to a floor loaded by a centrifugal compressor, at the opposite end of the

shaft of the Expander. Mounted on a steel support. The Expander compressor is equipped

with complete systems of sealing gas. [2]

II.4.1. Seal gas system:

The Turbo-Expander is supplied with sealing gas from the discharge of the product gas

from the compressor during normal operation of the machine, as it is also supplied from the

dry gas joint network of the three trains, the latter source power is provided to maintain a

desired pressure of the sealing gas system also is useful during startup of the machine in the

expander, the production gas contained around the shaft by a labyrinth located between

bearings, thrust and back of the compressor and turbine wheels. The turbine exhaust pressure

is higher than the compressor inlet pressure, is the pressure on the back of the turbine wheel

which is used to control the injection pressure of the sealing gas injected at the labyrinth will

flee to the back of the compressor and turbine wheels, And to the bearings for completing

dual role:

Thermal barrier to protect the bearings.

Barrier for avoiding oil to it, and to keep the parts of the machine cold.

The previous Figure (II.5) shows the sealing system of the Turbo-Expander.

II.5. ACTIVE MAGNETIC BEARINGS:

An active magnetic bearing is an electromagnetic device that maintains the relative

position of one revolving assembly (rotor) with respect to a fixed part (stator).

Electromagnetic forces implemented are controlled from an electronic control unit.

Therefore, an active magnetic bearing consists of two distinct parts, the bearing itself and the

electronic control system.


34

II.5.1. Bearings:

Each compressor-expander comprises an active magnetic bearing system. This system

includes two radial magnetic bearings, active magnetic bearings abutment in both directions,

two sets of auxiliary bearings, all necessary position sensors, a speed sensor and a control

system. The auxiliary bearings used are pairs of pre angular contact ball bearings with

ceramic balls loaded. When the rotor is not in magnetic levitation, it is supported at its ends

by a pair of these ball bearings. Note that the start cycles and making the normal case does not

involve auxiliary bearings. The control unit ensures the rotor position control and provides

instrumentation signals required for the control and protection of the machine. View details of

the system in the C3 level, "Schema piping and instrumentation". As the support of the rotor

depends on proper operation of the control unit, it must be connected to a power supply

system for battery failure (UPS- Uninterruptable Power Supply) installed inside the cabinet

AMB.

Magnetic bearings and position sensors are mounted inside the bearing housing of the

turbo expander-compressor. The electronic control system is installed in the control room (a

non-hazardous area) and connected to the magnetic bearings by electric cables. [6]

II.6. FACTORS NEGATIVELY AFFECTING THE WEALTH:

The presence of water in the natural gas and the operating conditions, high pressure and

low temperature in a raw gas treatment process are parameters that can promote the formation

of hydrates (ice), a phenomenon that can affect the normal development the process and good

recovery of liquid hydrocarbons, causing clogging of pipes and equipment (poor separation in

the balloons, poor regulation valves ... etc).

To prevent hydrate formation, an injection of glycol was provided under various rights at

low temperatures or other method by adsorption dryers molecular sieves. But a second factor

can also occur and adversely affect the recovery of heavy hydrocarbons; this phenomenon is

called foaming and caused by the presence:

-Of solid non eliminated prior suspension.

Corrosion inhibitor in conjunction with other chemicals.

Of Salts.


35

There are other problems with the balloons, which are mechanical in nature and can cause

this phenomenon, it is:

Of Demisters (sieve) deteriorated.

Of Baffles displaced from their normal position.

From Detached deflector.

As can be also favored by a high rate of hydrocarbons (turbulence). [1]

To remedy the problem of icing should be done:

Strict control of injection rates calculated based on the amount charged .

A clearing of methanol injectors.

A momentary injection of methanol in frosted points.

A hot regime.

With regard to the remedy the problem of foaming must be:

Injecting an antifoaming agent.

Purge float cages (if the foam is in the balloons) liquid hydrocarbons.

Make a hot regime.

II.7. PRECAUTIONS AND RECOMMENDATIONS ON THE TURBO-

EXPANDER:

Observe the precautions / following recommendations to avoid any risk of damage to the

turbo-expander.

II.7.1. Cleanliness:

All pipes and other openings to the turbo-expander must be protected against the ingress of

contaminants because even the smallest foreign objects can cause serious damage to internal

parts of critical tolerances. Similarly, moisture may accelerate the electrolytic action on the

rotating parts and other surfaces and damage critical internal organs. Shipping plugs provided

must remain in place until the connections to the pipes of the plant are made.

II.7.2. Pressure tests:


36

The sealing in situ testing of the compressor-expander must be carried out with the help of

our service operator. After purging with nitrogen, the pressurization takes place by means of

the housing of the pressure equalization circuit. Take particular care to avoid penetration of

foreign bodies in the control system and sealing, bearings, game pads and sealing areas of the

rotor. This accidental contamination can result from a pressure build-up or excessively rapid

decompression. In case of known or suspected contamination, the machine and the barrier gas

circuit must be completely disassembled to be checked and cleaned. To prevent damage to the

trim, high differential pressures across the linings should be avoided. [1]

The pressure rise rate should not exceed 2 to 3.5 bar (30 to 50 psi) per minute.

II.7.3. Effects of Methanol and Glycol to magnetic bearings:

Glycol and methanol are often used in the processes to turbo-expander to prevent hydrate

formation during cryogenic expansion. In the case of plants turbo regulators with magnetic

bearings, keep in mind that exposure to glycol and methanol resulted in the failure of

windings and magnetic bearing sensors .As the process gas is used as "barrier gas", for

cooling the magnetic bearings during operation, it is essential to ensure that the process gas

used as a barrier gas contains no glycol or methanol. In addition, it is important that during

the pressurization, starting and stopping the process control sequence is such that no glycol or

methanol comes into contact magnetic bearings. [2]

II.7.4. Procedure prior to the start:

The majority of the compressor-expander problems occur during the initial start-up period

of the plant. This critical period usually lasts several weeks since the initial launch of the

regulator until the temperature and pressure of the installation are standardized and all

associated equipment is stabilized.

II.7.4.1. Control:

During transport, installation and operation, pipe fittings and flange bolts may loosen.

Check and tighten if necessary. Check that all electrical circuits, switches, sensors, controls

and safety devices are properly connected, adjusted and operational. Check that all shutdown

systems are operational.


37

This system is integrated security. Therefore, verify that the loss of pneumatic signals has the

effect of closing the shutoff valve.

See controls operation of external devices in the tender documentation attached providers.

Check that all pneumatic systems and components are properly set, connected and

operational.

II.7.4.2. Anti-pumping valve:

Check that all electrical connections and devices pneumatic are correct and tight.

II.7.4.3. Pneumatic systems:

Check that all pneumatic systems and components are properly set, connected and

operational.

II.7.4.4. Thrust balancing system:

Due to the nature of the magnetic bearings, each axial bearing exerts a force of about 40%

capacity (21.3 KN or 4800 lb to 13 A), even in the absence of external loads. If, for example,

an external axial load of 1.8 kN (400 lbs) is applied to the rotor, one of the axial bearings its

load decrease from 21.3 to 19.5 kN (4 800-4 600 lbs), while the other bearing will increase

the own of 21.3 to 23.1 kN (4 800-5 000 lbs), which has the effect of keeping the rotor at

substantially the same location while absorbing all of the filler external 1.8 kN (400 lb). As

electronics at extremely high throughput, magnetic bearings have good capacity to respond to

transient loads.

II.8. ADVANTAGES AND DISADVANTAGES OF TURBO EXPANDER:

II.8.1. Advantage:

The advantages of using a Turbo Expander are:

Used in the methods of treatment, separation and gas liquefaction.

It ensures a good performance compared with other relaxation systems.

It brings a better recovery of the condensable fractions of natural gas.

Utilization of work provides by relaxation to feed the compressor.

Their large production capacity (for large facilities).


38

II.8.2. Disadvantages:

The disadvantages brought by the use of a Turbo Expander are:

It confronts the mechanical wear problem, like any rotating machinery.

High cost of installation linked to the material used and in the manufacture of these

elements.

Cooling problem related to the very low temperature.

Forming droplets that can abyss the fins of the Expander. [3]

II.9. DESCRIPTION VALVE JOULE-THOMPSON (JT):

II.9.1. Description:

This is a valve which has the role of relaxing the gas passing through it, it is composed of a

valve body assembly in which the fluid flows, the control mechanism, the actuator which

controls the flow and Accessories specific to each particular application. Sealing is provided

by headquarters, gaskets and seals. The connector nut connects the rod to the control shaft of

the actuator. The internal parts of the valve assembly body are characterized by their

simplicity and effectiveness. The fluid passes through the stack from the outside in and flows

to the outlet port. [1]

The figure below shows the model of a valve Joule Thompson.

Figure (II-6): The detailed diagram of the Joule Thompson valve.


39

II.9.2. Operating principle:

Stacking allows flow variations while limiting the velocity of flow through the element,

the stack consists of a number of disks in which the labyrinths have been drilled so as to allow

a predetermined flow rate.

The passage independence is developed by a series of bends at right angles, each passage

having a determined number of bends to limit the velocity to the expected value. Each disc

having a given capacity, the total flow through the element can be easily conducted and

controlled accurately. The piston position within the stack determines the flow rate by reading

more or less passages in the discs. [3]

A maximum flow rate being determined for each disk, the control element can operate at a

fixed velocity and settled on the whole field of design capacity, to minimize velocity changes

that normally produce noise, spray, cavitation, vibration and erosion.

II.10. ADVANTAGES AND DISADVANTAGES OF USING THE VALVE

JOULE THOMPSON (JT):

II.10.1. Advantages:

Light process (no rotating machines).

Insensitive to changes in gas flow rates to be treated.

Low investment.

Dehydrates the gas simultaneously.

II.10.2. Disadvantages:

Low liquid recovery (only ).

Sensitive to variations in pressure of the gas to be treated.

Requires a high upstream pressure.

Requires injection of an inhibitor to prevent the formation of hydrates.

The gas pressure is greatly lowered.


40

II.11. CONCLUSION:

In this chapter we conclude that the study of any industry machine requires complete mastery

of how it first secondly taking account of all constraints related to the operation and of the

role of this machine in the process.

CHAPTER III

Treatment of

Natural Gas

Chapter III Treatment of natural gas

41

III.1. NATURAL GAS:

III.1.1. Introduction

Broadly, any natural substance that is in the gaseous state under normal temperature and

pressure is a gas. These substances are reduced in number and those that are found in the

earth's crust are more limited: it is essentially saturated hydrocarbons of a lower carbon

number five, carbon dioxide, nitrogen, hydrogen sulfide, hydrogen, helium and argon.

Natural gas is playing increasing role energy. The importance of these reserves and its

advantages on the environmental plan promotes its use. Especially in high value added

sectors: Precision Industry electricity production. The implementation of this energy is based

on the technical mastery of the entire gas chain, ranging from extraction to users through

storage, transportation and distribution.

III.1.2. Natural Gas Reserves in the World:

About 2/3 of the world's proven natural gas reserves, the duration of life at current

consumption is 60 years, are concentrated in Russia and the Middle East (Iran and Qatar).

With the discovery of new fields (particularly in the offshore zone of Asia / Oceania) and the

revaluation of existing fields outside Europe, global reserves increased by 30% during the

past decade. [3]

In Europe: however, reserves fell by 40%, mainly as a result of the rapid depletion of

deposits in the North Sea. Offshore reserves have gained importance, they now account for

40% of global gas reserves.

Beyond the reserves, there is a significant potential for conventional gas resources remaining

to be developed and which would represent about 120 years of consumption. In the future, the

Middle East and the CIS (Commonwealth of Independent States) should cover an increasing

share of world gas production.

In 2011, production of Russia recorded a strong increase of 3% and the country is the second

largest producer after the United States with a share of 19% of the global volume. This

country should quickly regain its leading position worldwide in 2035. The countries of the


42

Caspian Sea (Black Sea), Turkmenistan at the head, will also play an important role. In 2011,

gas production in Turkmenistan jumped dramatically from over 40% to meet the external

needs (China).

The Middle East is rapidly strengthening its role as a producer and exporter on the

international stage. Under the leadership of Qatar, this region experienced growth fastest

production last 5 years and has become an export area size providing 16% of the international

market in 2011. With over 40% of world reserves, this region occupies a central position

between Europe and Asia, has a key role to play in the global gas balance. [3]

It should also be noted the rise in production in China, the US and Australia. With a

prodigious development of its unconventional gas, the US has downgraded Russia becoming

the largest producer in 2009. Their production will continue to increase rapidly, enhancing

their export potential to internationally.

Figure (III-1): Distribution of natural gas reserves in the world.

III.1.3.Evolution of reserves of conventional natural gas:

Proved reserves are those quantities of conventional natural gas from known accumulations

which according to geological information and current technological advances, have a high


43

probability of being exploited in the future, within the existing technical and economic

conditions.

The conventional natural gas reserves are important and estimates of their size continues to

evolve as new exploration or extraction techniques are discovered.

Resources are relatively well distributed worldwide. At present, Russia, Qatar and Iran share

nearly 50% of proved reserves; the Middle East has experienced the sharpest increase in

recent years.

Several analyzes estimate that most of the conventional natural gas yet to be discovered.

The world's proven reserves have doubled in 20 years to reach 186,000 billion cubic meters.

Figure (III-2): Evolution of reserves of conventional natural gas.

III.1.4. The gas production in the world:

World production of natural gas is increasing steadily for 40 years. It tripled between 1970

and 2010.

In the largest producers in 2013 were the United States with 20% of world production

(including unconventional natural gas), Russia (18%), Qatar (5%), Iran (5%) and Canada

(4%).[3]


44

2/3 of the world production is provided by 10 countries. It is important to note that if the

Middle East accounts for almost 43% of proven world reserves, it represents only 17% of

world production.

Figure (III-3): Natural gas production capacity in the world (%)


45

Table (III-1): Some gas producers in the world (2010-2013)

Producing countries Production Mm³ Share of world total (%)

Russia

United States

Canada

UK

Norway

Iran

Netherlands

Indonesia

Saudi Arabia

669,700

681,400

143,100

92 ,045

114,700

162,600

80,780

77,305

103,200

21.8

18.0

6.5

3.2

3.1

2.9

2.7

2.7

2.4

Other 1049,801 36.5

Total 3174,631 100 .0

For now, only about 15% of world gas output is subject to international trade, with three-

quarters through pipelines and the rest in the form of liquefied gas.

Russia accounts for 22% of global output, 90% of Russia’s production come from western

Siberian fields: Urengoy is the main, largest deposit.

In the world, with 10,000 billion of reserves and 35% of Russian production; other:

Yamburg (5000 billion , 28% of production), Medveje (11% of production) and Orenburg

(5% of production).

The decline in European stocks led to a production slowdown that should fall from its

current level of 310 G to 260 G by 2020. By then, the gas needs of member countries of


46

OECD Europe pass 690 G , which would imply a deepening European dependence à-vis

imported gas. In 2030, domestic production no longer covers only the fifth European needs.

The faster decline than expected North Sea production has overtaken all gas operators.

New infrastructure completed in 2005 do not yet seem sufficient.

Scalded by the tension observed in March 2005, put the gas operators were exploited to

fulfill their maximum storage (useful stocks represent 25% of annual consumption in France

against only 3% in the UK). But the withdrawal of British stocks begins in early November,

with almost a month in advance. Because the decline of British fields in the North Sea also

greatly reduces the ability to "swing" (the "swing" variation is the maximum capacity of

production in the North Sea production is limited summer and winter maximized) . Thus it a

few years ago, producers could increase their production in the winter to meet seasonal

demand. But since peak production, they produce a maximum capacity (by restricting the

"swing" capacity). The decline is worse in the winter period of high demand. Also, with the

sharp drop in temperature, the double price.

As for North America, production experienced a relatively slow decline in 30 years, as

demand was inhibited by energy policy, while the number of drilling the well exploded to

compensate for reduced productivity. Now demand rises, but production of the continent is on

the brink of the cliff.

Africa is experiencing a sharp increase in production, accompanied by an increase in

exports. That is to say, it consumes little energy it has and, therefore, cannot develop.

In the future, the Middle East, CIS and offshore should represent an increasing share of

world gas production. It should be noted that the Middle East will now provide 10% of the

international market despite its reservations. This is a major difference with the oil of which

30% of production comes from this region.

For that Algeria, in 2005 we produced 143G .

In 2002, the primary production of natural gas reached 140 billion m3.

Hassi R'Mel production, which amounted to 102 billion , is contributing 73%.


47

An important part of the primary gas production is used in the process of exploitation of

deposits for recycling, re-injection or consumption. The amount of gas held for sale was 81.4

billion m3.

Upgrading facilities such as natural gas liquefaction plant at Arzew and Skikda has

allowed Algeria to increase its production capacity to win today 11% gas market share

consumed in the European Union, a level that, with the prospect of doubling exports will be

close to that exported by Russia, the EU partner in the energy field.

In the coming years, the map of gas production will undergo substantial changes:

In the CIS, the Russian deposits in Eastern Siberia and on Sakhalin Island will go into

production and contribute to the balance of the Asian markets. In western Siberia, the

commissioning of new fields (Bovanenkovo, etc.) will soon become necessary to

offset the declining production of old giant fields (Urengoy, Yamburg) providers in

Europe. Moreover, given their strong gas potential, ultimately, the Central Asian

countries (Kazakhstan, Azerbaijan) will play a major role on the international market,

either through direct export or through the Russian gas network.

The development of US reserves of Alaska is a growing contribution of

unconventional gas to local gas production.

The emergence of new major producing countries in Latin America (Bolivia, Peru,

and Brazil) will offset the slowdown of the Argentine production.

The gas fields into production partner, to liquefaction (Angola, Nigeria), contributes to

progressively restrict the volumes of gas flared and improves the rate of recovery.

A major portion of the gas expansion will be based on a single super giant

accumulation of non-associated gas, operated by two countries, Qatar (North Field)

and Iran (South Pars), whose proven reserves are 21% of the world total. [2]


48

III.1.5. Consumption of Natural Gas in the World:

Natural gas first appears as the source of energy most suited to meet the expectations of

the consumer countries, and most of them favor its use wherever it can replace oil.

In nearly 40 years, its share of the coverage of world primary energy demand jumped

15.9% to 23%, while that of oil down 43.6% to 35%. In some countries such as Russia and

Argentina, the use of blue or even exceeded that of black gold.

Yet the repeated credo since the first oil shock of 1973, in which the gas would be safer,

suffered a serious contradiction in January 2006 (when the gas crisis between Russia and

Ukraine); the nations that have the most resources to the now using political and diplomatic

purposes.

The twin oil energy is becoming an important means and continuity of supply is a concern,

especially as proved reserves are concentrated in three countries: Russia, Iran and Qatar who

hold two-thirds, the sixteen others, including Algeria share 1-5% of these reserves.

Today's conflicts are less about the control of the current market and on the future because

natural gas will remain plentiful when oil will run out.

III.1.6. The Gas in Algeria:

Algeria is ranked fourth in terms of proven reserves with almost 4.6 trillion cubic meters in

addition to about 1,000 billion m³ considered probable and possible reserves.

It also: second African producer after Nigeria with an annual output of nearly 152 billion

cubic meters, the third largest exporter of natural gas with a capacity to export 65 billion

cubic meters, and holds second place in the export of LPG.

Other gas is transported by pipeline to Italy, Spain, Portugal, Tunisia and Slovenia, while

the LNG transport it in a liquid state to France, Spain, the US, Turkey Belgium, Italy, Greece

and South Korea. We cover 60% of Spanish needs, 36% of Italian needs and not less than

10% of total gas demand across Europe, and this tells us (with the condensate, produced 16

MT / year and LPG ) over 60% of foreign exchange earnings.


49

Do not forget the two gas pipeline project: MEDGAZ to Spain and GALSI to Italy, which

should have initial capacity of 8 billion cubic meters each. (Figure 3)

The Algeria, a pioneer in the field of gas liquefaction, is involved in projects in Peru,

Venezuela, Niger, Libya, Italy, Yemen, South Africa and Mauritania.

Finally, our country has a powerful instrument that black gold to good use is that gas

pipelines will transport not only more gas to please our customers, but also and above all

"ideas" [3]

Figure (III-4): The Algerian gas export routes.

III.1.7. Outlook:

Despite the persistently high price outlook, economic growth rate coupled with obligations

to respect national Kyoto commitments, continue to offer the new blue gold bright prospects

for development.

Thus, world gas demand is expected to grow at a rate of about 2% per year by 2020 against

1.4% for oil and coal. At this rate, the gas will lift dice 2015-2020 as the second source of


50

energy instead of coal. The International Energy Agency expects a doubling of consumption

by 2030, which will represent nearly 24.2% of world primary energy demand.

LNG trade could represent 38% of world trade in 2020.

This growth will be moderate in developed countries, which continue to invest in

improving the efficiency of energy uses. On the contrary, a significant increase is expected in

the newly industrialized countries and developing countries, particularly in Asia and Africa

due to population growth and the implementation of large energy-consuming activities,

localized today in developed countries.

The North American and European markets could continue to grow at a rate of 1.7% per

annum and 2.2% per year respectively.

In the US, improvements in the operation of equipment and tax credits on solar

technologies and micro turbines to reduce energy consumption in the home will have an

impact on the use of gas in this sector. Thus, the gas demand would improve slightly in the

residential / tertiary sector.

Moreover, the gas price increase could also slow growth in the electricity sector, in favor

of new coal plants, the adopted measures also include the commissioning of new nuclear

capacity by 2030.

In non-OECD Asia and the Middle East growing gas demand could grow at a rate of about

3.5% by 2020.

Asia (India, Indonesia ...) fertilizer production is expected to require increasing volumes of

gas both as a fuel and as a feedstock for the production of urea and ammonia.

In the Middle East, natural gas is increasingly used in seawater desalination plants and in

general throughout the industry (Figure III-4).

The Tunisian and Moroccan governments are considering increasing the share of natural

gas in the national energy balance of 8% in 2006 to 24% in 2020 respectively for the first and

23% in 2020 for the second.


51

We must talk about the African project called Trans African gas pipeline, the former Nigal

project, which runs from Nigeria, via Algeria probably join the great Hassi R'Mel deposit to

go to Europe. This pipeline has structuring economic effects, will try to supply neighboring

countries such as Mali, Niger, with suspenders, although consumption in these countries is

still low. This gas comes from gas flaring in Nigeria, and will thus reduce flaring and

contribute to environmental protection. The volume is between 15 and 20 billion cubic

meters.

As for Algeria, it set the goal of exporting 85 billion of gas per year by 2010 and 100

to 120 billion in 2020, as there are in reinjection gas consumption needs and local, so

there will be a production of 117 billion cubic meters in 2010 and 2020 to 172 billion cubic

meters.

Although some say the lack of realism of a gas market similar to that of the medium or

short term oil, because of the lower energy efficiency and transportation cost, saying only the

GTL option, if it is developed large scale, in more favorable economic conditions could

perhaps accelerate the process, they can completely disabuse specialists who predict that the

peak of world production of natural gas will occur in 2030 or about 20 years after that of oil,

which is in the ideal transitional fossil energy should continue to play a key role in the energy

mix of tomorrow.

In conclusion, we say that natural gas today is not about oil (having forty years in

advance), and like oil once these perspectives lot of hope but also include a number of risks.

The blind optimism of some commentators deserves to be tempered because natural gas is

certainly not a magic potion that by its own virtues will solve all difficulties. [1]


52

Figure (III-5): Regional demand outlook.

III.1.8. Characteristics of Natural Gas:

III.1.8.1. Density:

The density of a gas is the ratio of its density to that of air under the conditions determined

temperature and pressure. It can also be obtained from the molecular weight that can be

defined by its chemical composition using the following relationship:

Gas density = molecular weight / 28.966

III.1.8.2. Calorific value:

It represents the quantity of heat released during the combustion of a unit volume of gas

measured under reference conditions. It is expressed by [Joules / m³].

There are two types of heating value:


53

Superior calorific value (SCV): corresponding to the heat when all the combustion

products (hydrogen or hydrogen products) are brought back to ambient temperature,

the water formed being in the liquid state.

Inferior calorific value (ICV):

Corresponding to combustion in which the water remains in the vapor state. ICV differs from

the SCV of a quantity of heat which equals the latent heat of vaporization of water.

III.1.8.3. Chemical composition:

It is used for the vaporization of study. It is also used to calculate some of the properties of

the gas in terms of pressure and temperature (compressibility, density) and to define the

conditions of his treatment during the exploration (extraction liquid products).

III.1.9. The different types of Natural Gas:

Depending on the composition and regional disparity, generally there are three types of

natural gas:

1- The non-associated gas, which is not in contact with the oil.

2- The associated gas "coverage" (gas-cap gas) that overcomes the oil phase in the tank.

3- The associated gas dissolved in oil in reservoir conditions.

In addition, dry gas is a gas which does not contain readily condensable products at the

temperature and ambient pressure (that is to say it consists of methane, ethane, and some non-

condensable impurities: carbon dioxide, nitrogen, etc. ...).

In fact, no gas is dry, properly speaking; however, it is customary to apply this definition

to the gas, the condensable fraction is low.

Natural gas is said when wet, cooled to room temperature, it provides a liquid phase.

A natural gas condensate is said when the composition of hydrocarbons contained therein is

such that an isothermal expansion produces a liquid phase.


54

III.1.10. Utilization:

In half a century, the gas expansion was marked reversal of trends, resource scarcity fears

that have led to the adoption of energy policy measures aimed to reserve natural gas for noble

purpose (European Directive prohibiting the use of natural gas in power plants) is the best

example.

Then the old relative of oil, which has a priori no captive market, quickly gained acclaim

thanks to a great flexibility of use compared to competing fuels, this technical superiority is

particularly noticeable in the field of electricity generation: he assured 20% of electricity

worldwide in 2006, and this share is increasing (new plants combined cycle should absorb

half the world growth of natural gas) (See Figure III-6).

In particular, 30% of gas consumption is for the residential / tertiary sector (particularly for

heating, hot water and cooking).

The new blue gold is also the raw material for much of the chemical and petrochemical

industry, almost all of the production of hydrogen, methanol and ammonia based products for

fertilizer industries , plastic resins, solvents and petroleum refining (for additives). However,

this use is recessed with 4% of the product gas compared to the industry which absorbs 25%.

Finally, a few years after the LPG, compressed natural gas bottles used as fuel for vehicles

(NGV), more than a million vehicles drive with the world, particularly in Argentina and Italy.

Note also that the synthetic diesel, which resembles to misunderstand diesel can be

produced from natural gas; the chemical conversion of gas into liquid fuel (GTL / gas to

liquid), could be a new opportunity and an attractive alternative offering a high quality diesel

fuel (no sulfur and aromatics, cetane very high) that can be directly used without adaptation of

the engine. However, its development is difficult, still handicapped by low energy efficiency

compared to petroleum products (55-60%), high costs and high emissions of carbon dioxide

linked to production. [2]


55

Figure (III-6): Breakdown of the uses of gas in 2004 and 2020.

III.1.11. Processing of Natural Gas:

Gas treatment is to separate at least partly some of the components present at the outlet of

the well (such as water, acid gases and heavy hydrocarbons), to bring the product to transport

specifications or commercial specifications.

This generally involves a succession of steps aimed at:

Purification and Dehydration:

It may be necessary to remove at least partially:

Water which leads to hydrate formation.

Mercury is extremely dangerous to humans and in some cases corrosive to equipment.

The carbon dioxide (corrosive and thermal zero value).

Hydrogen sulphide (toxic and corrosive).

Nitrogen (thermal zero value).

Fractionation of hydrocarbons: It is done mostly by temperature reduction, and leads

to obtaining the following liquids cuts:

a- Gasoline or condensation: light gasoline (C5+ fraction).

b- The LPG fraction (LPG): includes propane and butane.

The mixture of gasoline and LPG (also containing C2) is called "liquefied natural gas" (LNG).


56

In addition to the "dry gas" part, which can be liquefied at (-160 ° C) in specific facilities

to be transported as liquefied natural gas (LNG).

The condensate and LPG have such market value as some deposits are mined only for

them; the gas is fed back either totally or partially progressively into the reservoir to increase

the pressure and recover the final more LPG and condensate.

III.1.12. Specification of the treated gas:

In the case of pipeline transport:

The specifications aim in this case to avoid the formation of a liquid phase (water or

hydrogen), the locking of the conduit by hydrates and excessive corrosion. Is imposed for this

maximum value to dew points. The value of the hydrocarbon dew point depends on the

conditions of transport and can for example be set at 0 ° C, to avoid formation of liquid

phases by retrograde condensation.

In the case of a commercial gas:

The specifications are more stringent and also include a range within which must be calorific.

Typical specifications for commercial gas are shown in the following table:

Table (III-2): Specifications of commercial gas.

Value Unit

Dew Point < -6 °C

Water content < 150 ppm vol

content C5+ < 0.5 % mol

Superior Calorific power SCP 39100- 39500 KJ/m³ (n)


57

The H2S content that may contain processed gas is generally very low and usually varies

between 2 and 20 mg / m³ (st). A common specification, in Anglo-Saxon unit, is 0.25 grains /

100 Seft either 6 mg / m³ (st) or about 4 ppm.

When natural gas is liquefied, pretreatment should prevent any risk of crystallization in the

heat exchangers of the liquefaction unit. A split between methane and heavier hydrocarbons is

generally operated during liquefaction.

Therefore, the gas obtained after arriving at the LNG regasification receiving terminal can

in principle be directly sent into the distribution network. If the gas undergoes a

transformation by chemical conversion, the pretreatment depends on the nature of the

conversion process used. The use of catalysts, in particular, imposes specifications that are

frequently very severe.

III.2. LIQUEFIED PETROLEUM GAS (LPG):

LPG is a mixture of hydrocarbons having a low molecular weight with three or four carbon

atoms, that is to say: propane, propylene, n-butane, isobutane, and butenes, in varying

proportions. The butane and propane are the main components.

The production of this fuel is derived from crude oil processing in refineries and separation

(outgassing) of natural gas (methane ethane). Liquefied petroleum gas may also contain small

amounts of methane, ethylene, pentane and pentenes and exceptionally hydrocarbons such as

butadiene, acetylene and methyl acetylene. [7]

These hydrocarbons are present only as byproducts of the production of olefins

petrochemical use (steam cracking). Apart from hydrocarbons is also find some sulfur

compounds (mercaptans and alkyl sulfides) in extremely small quantities, but have some

significance regarding the corrosiveness of the product.

LPG is easily liquefying gas at ambient temperature under low pressure (4-18 atmospheres):

this allows storage and transportation easier for non-condensable gases such as methane,

ethane and ethylene which require very high pressures to be liquefied at ambient temperature.


58

III.2.1. Liquefied Petroleum Gas in the world:

World production in 2004 reached 213 million tons. World production of LPG is growing

at 5% per year.

60% of world production comes from natural gas, 40% of the refining of crude oil

(1Tonnes of petroleum Gas gives 20 to 30 Kg LPG).

In that year, the LPG demand for residential and commercial heating in Asia exceeded that

of North American residential and commercial combined chemical sectors.

Consumption in the EU in 2004 is 16.5 million tones.

In the United States, where a long tradition of use exists, production and consumption are

balanced.

In the Middle East, production of LPG has grown significantly in the late 70s when the

increase of energy prices made attractive recovery of propane and butane. Previously, these

products were burnt with associated gas. This region is currently the main source of export of

LPG in the world.

Algeria and North Africa, where LPG is mostly recovered from the natural gas

liquefaction units, refinery production ensures the complement, propane and butane are

recovered at the atmospheric distillation of crude oil and by cracking of heavy molecules in

most processing units and conversion.

Propane and commercial butane are not pure compounds but mixtures, complete separation of

molecules is also expensive useless because most uses Allow mixtures.

III.2.2. Liquefied Petroleum Gas in Algeria:

Production fell to 8.4 million m3 in 2006 against 8.6 million m

3 in 2005.

85% of production comes from gas units fields (Hassi R'Mel, Stah, Alrar, Tin Fouyé

Tabenkort, Hamra, Rhoude Nouss, Hassi Messaoud, Berkaoui and Oued Noumer). Total

production of LPG is transported via pipe LR1 (998 Km), itself connected to central storage

and transfer (CSTF) located at Hassi R'Mel. There they got rid of any traces of water before

being shipped to the SP4 pumping station and then transported to the complex separation of

Arzew and Béthioua. The rest of the production comes from LNG units in Skikda, Bethioua

and refineries. Our country exports 8.04 million tons of these materials in 2003, supplying 23

countries.


59

In the domestic market, volumes sold totaled 1.85 million tones; the growth rate during

2005 on the LPG market is 1.5%.

The national consumption of LPG (90% essentially of butane) is satisfied through the

territory by routing products for the various regions by tankers, cabotage vessels and recently

by rail through the transport company energy products (TCEP).

During the last decade, the Algerian LPG industry has undergone profound changes,

particularly in terms of production, export and shipping.

III.2.3. Algerian exports of the Liquefied Petroleum Gas:

Mediterranean: 80% (France, Italy, Spain, Portugal, Morocco, Turkey, Egypt, Lebanon,

Tunisia, Syria).

USA: 14%

Latin America: 3% (Brazil, Mexico, Ecuador, Guatemala, Puerto Rico)

Asia: 2% (Korea, China, Japan, Singapore, Australia)

Northern Europe: 1% (Holland, Sweden, Belgium, Finland, England)

The gas resources development program, launched in the early 90s, is today Sonatrach benefit

of large supplies of LPG. Since the commissioning of the gas field Hamra in 1996, LPG

production has followed a steady growth. It should reach a volume of 11 million tonnes with

the commissioning of new facilities.

III.2.4. Use of the Liquefied Petroleum Gas:

The main domains of use of LPG are:

Combustible: cooking, hot water or heating, supplied by distributors in liquid form, bottled or

bulk. In some cases, customers are supplied from networks or propane air as propane or

butane as in Corsica. It is used by individuals or as industrial combustion gases.


60

The use in the tertiary residential sector (cooking) is concentrated mainly in Spain, France,

Turkey and Italy. Worldwide, nearly 500 million households and one in two in the European

Union use.

in air conditioning: In air conditioners or refrigerators:

Either LPG absorbs heat from the environment to evaporate and creates a cold.

Either an engine running on LPG can drive a compressor which compresses the gas "LPG"

and relaxation absorbs heat.

As fuel: The combustion of LPG is clean enough, it produces no soot, no carbon

monoxide, unburned hydrocarbons relatively few and relatively little carbon dioxide

compared to other fuels derived from petroleum. Furthermore, the unburned hydrocarbons

from the combustion of LPG are short carbon chains, and therefore less toxic than their

counterparts from gasoline, diesel, or oil.

It is a fuel that preserves vehicle performance and even reduces engine wear.

LPG represents 60% near the park "essence" in the Netherlands, over 30% in Italy, 40 to

60% in the US and Canada.

The use of LPG in Algeria remains very low, with only 120,000 vehicles were converted to

liquefied petroleum gas.

Experts explain the wrong that Algeria is producing LPG / C, a transport sector that

depends 96% liquid hydrocarbons. "Transport consumes today nearly 2/3 of final

consumption of petroleum products, while consumption of LPG / C is only a small part."

Forecasters say that if Algeria continues to use more diesel and gasoline at the expense of

LPG, it will eventually be forced to import diesel to meet increasingly growing market.

In Europe, sales as fuel (50% butane - propane 50%) are concentrated to 90% in Italy (1

million units) and the Netherlands (500,000 vehicles or 8% of the park). In France, in 2004,

180,000 light vehicles and 135 buses use LPG as fuel with a consumption of 151 000 T.

In Japan, Tokyo 250,000 taxis using LPG.


61

Table (III-3): Uses of Liquefied Petroleum Gas in France and worldwide

World France World France

Residential and

commercial 50 % 61 % Fuel 6 % 9 %

Chemistry and Refining 35 % 13 %

Agriculture 2 % 17 %

other industries 13 %

LPG in the industrial sector, other than chemistry is important in Germany (25% of use)

because the LPG combustion flame can be in direct contact with the products, food

processing, glass, ceramics, metallurgy ... The agricultural sector is important in France, in the

heating of buildings poultry farms and pigs, greenhouses, drying crops ... propane is also used

as fuel for forklifts: 110000 Tonnes in France in 2004.

LPG is also incidentally used in lighters (butane).

In the petrochemical domain:

Domain where Algeria is determined to catch up due to any investment decision which

was spread for good numbers of years. At the moment, it is the most targeted sector projects

and reforms.

Liquefied petroleum gas is used as raw material for the production of ethylene, propylene,

ammonia, and MTBE.

18% of LPG is consumed as a feedstock for the petrochemical industry, mainly for the steam

cracking for the production of olefinic and aromatic bases. However, there are other

petrochemical uses of LPG.

Propane in the manufacture of petrochemical flagship product:

Ethylene;

Propylene by dehydration.

Ammonia by conventional reforming.

Acrylonitrile by Ammoxidation.


62

While butane participates in the development of:

MTBE (used as a booster of essences substitution in the PTE) by dehydrogenation.

Butadiene, by dehydrogenation.

Maleic Anhydride.

Propylene oxide by cooxidation.

III.2.5. Characteristics of Liquefied Petroleum Gas:

The physicochemical characteristics of LPG (distillation curve, vapor pressure, density,

calorific efficiency in engines, etc.) depend on their content of various hydrocarbons (see

Table 5).

Commercial products are very different from each other. In addition, their vapor pressure,

their density and their antiknock properties are very sensitive to changes in ambient

temperature.

Steam –Tension

At 20 ° C, LPG has a vapor pressure:

2 bars for butane.

8 bars for propane.

Density:

For propane: 0.51; for butane: 0.58.

Refined LPG is normally almost odorless and highly flammable, given their volatility.

They can give, upon contact with air, explosive mixtures. To better recognize or detect any

leaks, given a particular odor by appropriate substances (mercaptans).

LPG generally contains no lead or benzene and very little sulfur (<0.005% by weight),

which provides for the use of fuel a great environmental benefit. At atmospheric pressure, it

liquefies at a temperature of about -30 ° C.


63

The expansion of LPG is about 0.25% per degree Celsius, it must be taken into account

during storage (spheres should never be completely filled).

LPG is not corrosive to steel but usually is for aluminum, copper and its alloys. They have

no lubricating property, which must be taken into account when designing equipment for LPG

(pumps and compressors).

GPL with mild anesthetic potency if inhaled long and can cause headaches and stomach

aches.

LPG, when spreads in its liquid form, out of a pressurized container, evaporates generating

cold: in contact with the skin, it causes burns characteristics called "cold burns".

III.2.6. Liquefied Petroleum Gas specifications Gassi Touil (CPF):

This fraction must meet the specifications:

Content C2- ≤ 3% molar.

Content C5+≤ 0.4% molar.


64

Table (III-4): Characteristics of Liquefied Petroleum Gas components

Characteristics of LPG components

methane ethylene ethane propylene propane isobutane butylene butane

Chemical formula CH4 C2H4 C2H6 C3H6 C3H8 C4H10 C4H8 C4H10

vapor pressure at 10 °

C (kg / cm2) 370 45 32 7,7 6,2 1,3 1,7 1,5

boiling point at 760

mm Hg (° C) -161,5 -103,7 -88,5 - 47,7 - 42 - 11,7 - 6,2 - 0,5

Specific weight Kg /

Liter 0,3 - 0,37 0,52 0,51 0,56 0,6 0,58

liters of gas obtained

from one liter of

liquid

443 333,7 294,3 283,5 272,7 229,3 252,9 237,8

specific weight of the

gas at 15 ° C 760

mmHg Kg/ m3

0,677 1,18 1,27 1,77 1,86 2,45 2,37 2,45

Gross calorific

(Kcal/Kg) 13288 12028 12417 11700 11980 11828 11589 11586

Kg combustion air

per kg of gas 17,4 15 16,2 15 15,8 15,6 15 15,6

Octane number 120 76 99 83 96 97 84 89


65

III.3. THE CONDENSATE:

III.3.1. Generality:

The condensate, also said « more pentane » or « C5+ » or "well of natural gas liquids"

means the light fraction from pentane (C5 H12) to decane or more. Unlike the crude

condensate is not liquid in the deposits, but gas (due to the temperature), and condenses when

cooled by expansion to the wellhead.

This is an important contribution to world supplies, order of 6Mbep / J, and it comes to

more high quality liquids (light and low in sulfur).

It is rare that the amounts concerning the condensate are given explicitly; they are almost

always included in the crude oil, except for OPEC countries, as they are excluded from the

quotas. It also happens that the condensate produced by the deposits mined for crude oil is

counted with it, but as that produced by the gas fields to be counted separately (this is the case

in the USA for example). [1]

III.3.2. Properties of the Condensate:

Aspect:

It is a colorless liquid with an odor of gasoline.

Specific weight:

It is between 0.7 to 0.8 (N/ )

Flash point:

It must be less than - 40 ° C.

Flammable Limits:

Flammable, since it has a point below zero flash, its flammability limits are approximately:

1.4 to 7.6 vol (in air).

Vapor density:


66

Vapors are heavier than 3 to 4 times higher in terms of density relative to air.

Explosive and Flammable:

The Condensate is highly inflammable and evaporable fluid at normal temperature and

pressure, because it is not electrically conductive, presents a danger of fire or explosion due to

electrostatic discharge announced by casting, filtration, fall, spray, etc..... We must be careful

because the vapors of condensate are an explosive gas mixture is spread on the ground

because of its higher density than that of air.

Physiological toxicity:

Condensate vapors are toxic; when a person exposes himself, the first symptom noticed is

eye irritation monitoring neuropathy symptoms (dizziness).

Victim may eventually start yelling, singing, laughing stupidly, and end up having trouble

walking. When the concentration of vapor condensate is in the range of 0.025% to 0.05% by

volume in the air, they cannot cause serious harm, even after hours of inhalation.

Caution:

To avoid poisoning, one must achieve a proper ventilation of work and maintain

concentration of vapor condensate less than 300ppm.

Utilisation:

This fraction is especially valued in the domain of refining:

Oil-rich paraffinic and naphthenic ( - ), the condensate has a good potential to olefins.

It is used for fuel production, including species, their cost is lower than gasoline produced

from crude oil since the separation and processing of the condensate is less expensive and its

chemical composition rich in light elements.

It is also used for isomerization to obtain gasoline-isomerizate, transforming normal

paraffins iso-paraffins high octane and is also used in catalytic reforming.


67

Manufacturers today are learning to build on two fundamental pillars of sustainable

development: the human factor and respect for the environment.

From this idea was born the new policy that makes corporate magazines:

HSE policy: Health Security Environment.

CHAPTER IV

Thermodynamic

Study


68

IV. INTRODUCTION

As our work is based on thermodynamic considerations involving quantities such as

entropy, we found it useful to recall the general principles of thermodynamics and establish

quantitative forms expressing them.

According to a program called Thermoptim we using it to calculate the Enthalpy and

Entropy with the parameters (Temperature and molar fraction, pressure).

IV.1. DEFINITIONS

Enthalpy: a thermodynamic quantity equivalent to the total heat content of a system.

It is equal to the internal energy of the system plus the product of pressure and

volume.

H = U + PV ∆H = ∆(U + PV) =

Entropy: a thermodynamic quantity representing the unavailability of a system's

thermal energy for conversion into mechanical work, often interpreted as the degree of

disorder or randomness in the system.[4]

S =

∆S =

IV.2. CONCEPT ON THE RELAXATION:

Relaxation or expansion is the process that produces the cold in an LPG recovery plant.

The expansion may be performed in two ways:

Through a valve (also called Joule -Thomson).

By a machine (Turbo-Expander). [1]

IV.3. THERMODYNAMICS STUDY:

IV.3.1. First law of Thermodynamics:

The first law of thermodynamics to express the conservation of energy. It is written to a

closed system for the mass unit, neglecting the changes in kinetic and potential energy of the

flowing fluid:

∆U = U2 – U1 = Q + W

With:

∆U: Internal energy change.


69

Q: Heat quantity exchanged.

W: Work received or provided by the system.

IV.4. RELAXING WITH PRODUCTION WORK (TURBO-EXPANDER) G11-

KH-32-201:

Another type of relaxation may be performed in an expansion turbine; the energy of the

compressed gas is converted into work.

The expansion is thermally insulated, so the evolution occurs and there is an adiabatic

cooling of the gas.

In the real process, evolution is obviously irreversible due to friction force in the turbine.

However, in the idealized process, it is assumed that evolution is reversible.[4]

IV.5. THERMODYNAMIC ANALYSIS OF TURBO-EXPANER

PERFORMANCE:

The formulas and theoretical concepts set out below are those strictly required for

calculations of the cycles and turbo-expander performance.

IV.5.1. First law of Thermodynamics:

Applied to the turbo-expander, it is written between the inlet (1) and the outlet (2) of the

fluid:

......................................(1)

In adiabatic flow 0Q , this relationship becomes:

…..........................................(2)

For Turbine:

…………………………..(3)

IV.5.2. The specific heat of a gas mixture:

∑ ………………………………(4)


70

IV.5.3. The molecular weight of a gas mixture:

[ ] ∑ ………………………………………..(5)

IV.5.4. The isentropic exponent:

………………………………………………… (6)

IV.5.5. The specific gas constant:

: Constant universal of ideal gas =8,314[kj/mol.k].

: Constant real gas:

[ ]

……………………………..(7)

IV.5.6. Compressibility factor Z:

The calculation of compressibility factor Z is carried out using the following parameters:

, , , and such as: k

: The mole fraction of each component of the mixture.

: The critical temperature of each component of the mixture.

: The pseudo-critical temperature of each component of the mixture.

: The critical pressure of each component in the mixture.

: The pseudo-critical pressure of each component in the mixture.

The pseudo-critical temperature of this mixture is given by the following equation:

∑ ∑ …………………………..(8)

The pseudo-critical pressure of our mixture is given by the following equation:

∑ ∑ ………………………………………(9)


71

The reduced temperature is:

….........................................................(10)

The reduced pressure is:

…………………………………………. (11)

With:

: Operating temperature °C

: Operating pressure.

: Reduced temperature.

: Reduced pressure.

Correlation of S.Robertson:

[ ]…………..................(12)

………….................. (12.a)

…………........................... (12.b)

………….................... (12.c)

………….................... (12.d)


72

IV.6. WORKS RELAXATION:

Figure (IV-1): Diagram H-S side Expander.

This has as consequences:

An outlet temperature higher than due to the heating of gas by friction.

A drop in enthalpy lower than In summary:

………………………………(13)

………………………………..(14)

IV.7. METHOD OF CALCULATING THE EFFICIENCY OF THE

TURBINE:

It is interesting to measure the performance of a machine to compare the real development

of gas with the following characteristics:

QF = 0: no degradation of energy by friction (reversibility of energy transformations).

QF = 0: adiabatic engine: no heat exchange with the outside (the machine is

insulated).


73

The Efficiency of the adiabatic machine is finally the ratio of the actual work and the

isentropic work:

(

) ………………………………(15)

(

) ………………………………(16)

Or:

………………………………(17)

………………………………(18)

IV.7.1. Calculation of enthalpy and entropy at the entrance of the expander

H1 and S1:

In this section, the calculation of Enthalpy and Entropy is based on temperature T1 and

pressure P1.

Using the equilibrium diagrams of each component value is taken of Hi and Si to

corresponding state.

T1 Equilibrium diagram T2

P1 P2

The total enthalpy in point (1) (the inlet of the expander) equal to the sum of the enthalpy

changes in the process.

∑ ………………………………(19)


74

Where:

: The mole fraction of each component in the gas mixture.

In the same way: S1

The total entropy point (1) (the inlet of the expander) is the sum of the enthalpies.

∑ ………………………………(20)

IV.7.2. Calculating enthalpy, entropy discharge the output

expander :

In the case of a turbo-expander, the expansion in the turbine (expander) is associated with a

gas change of state and composition. After the discharge at a very low temperature; there is a

mixture biphasic (liquid - vapor); so the enthalpy at the outlet of the expander is the sum of

vapor and liquid enthalpies. [4]

………………………………(21)

Similarly way to entropy:

………………………………(22)

Th eref o re :

: Evaporation rate (represents the percentage of steam in the outlet of the machine).

: Enthalpy of the gas phase at the outlet.

: Entropy of the gas phase at the outlet.

: Enthalpy of the liquid phase at the outlet.

: Entropy of the liquid phase at the outlet.

IV.7.3. The actual work of relaxation:

…………………………………………. (23)


75

IV.7.3.1. Calculation in Expander side:

Inlet side:

elements Yi Mi ∑ Yi, Mi ∑Yi,

N2 0,0225 28,013 0,6302 1,0391 0,2337

CO2 0,0090 44,01 0,3960 0 0

C1 0,8630 16,043 13,8451 2,1256 1,8343

C2 0,0730 30,07 2,1951 1,4491 0,1057

C3 0,0222 44,097 0,9789 1,4197 0,0315

C4 0,0036 58,124 0,0209 1,3983 0,0050

C5 0,0012 72,151 0,0865 1,4320 0,0017

∑ 0,99 / 18,15 / 2.2119

elements Yi Pc ∑Yi, Pc ∑Yi,

N2 0,0225 33,99 0,7647 126,1 2,8373

CO2 0,0090 73,82 0,6644 304,19 2,7377

C1 0,8630 46,04 39,7325 190,5 164,4015

C2 0,0730 48,8 3,5624 305,4 22,2942

C3 0,0222 42,49 0,9433 369,82 8,2100

C4 0,0036 36,48 0,1313 425,16 1,5310

C5 0,0012 33,81 0,0406 460,39 0,5525

∑ 0,99 / 45,8392 202,5642

Kj/kg °K

Kj/kg °K

– = r 2.2119 - 0, 4580= 1, 75


76

1.2639

Pseudo-critical Temperature K.

Pseudo-critical pressure bars.

IV.7.3.2. Calculation of

X A B C

1,3089 1,1798 1,1094 0,1354 5,9219 0,8756

0,2032

IV.7.3.3. Calculation of :

X A B C

0,6111 0,1259 7.3191 0,3480

0,04569


77

IV.7.3.4. Calculating enthalpy, entropy inlet turbo-expander:

P1 = 65 bar

T 1 = -20°C

COMPOSITION Yi Hi ∑ Yi, Hi Si ∑ Yi, Si

N2 0.0225 496,15 11,1634 3,1 0,0698

CO2 0.0090 681,08 6,1297 4 0,0360

C1 0.8630 946,15 816,5275 5,07 4,3754

C2 0.0730 896,15 63,4480 3,86 0,2818

C3 0.0222 838,7 18,6191 3,4 0,0755

C4 0.0036 725,92 2,1331 2,6 0,0094

C5 0.0012 350 0,4200 2,68 0,0032

∑ / / 918,4408 / 4,8511

KJ/kg

KJ/Kg °K

IV.7.3.5. Enthalpy calculations, entropy output expander gas phase:

P2 = 23 bar

. T2 = -61 °C


N2 0,0043 467,3 2,0093 3,11 0,0133

CO2 0,0409 282,19 11,5415 0,91 0,0372

C1 0,8938 868,79 776,5245 4,89 4,3706

C2 0,0548 864,15 47,3554 3,76 0,2060

C3 0,0068 794,35 5,4015 3,33 0,0226

C4 0,0002 273,07 0,0546 1,1 0,0002

C5 0 288,79 0 1,18 0

∑ / / 837,4853 / 4,6499

837,4853KJ/kg

KJ/Kg°K


78

IV.7.3.6. Enthalpy, entropy calculations output expander liquid phase:

P2 = 23 bar

T2 = -61 °C


N2 0,0005 467,3 0,2336 3,11 0,0015

CO2 0,0123 282,19 3,4709 0,91 0,0111

C1 0,434 868,79 377,0548 4,89 2,1222

C2 0,2732 376,92 102,9745 2 0,5464

C3 0,1618 342,74 55,4553 1,77 0,2863

C4 0,0207 273,07 5,6525 1,1 0,0227

C5 0,0049 288,79 1,4150 1,18 0,0057

∑ / / 546,2566 / 2,9959

546,2566KJ/kg

2,9959KJ/Kg °K

813, 8115KJ/Kg

KJ/Kg °K

IV.7.3.7. Actual calculation of enthalpy, entropy output expander gas phase:

P2=29,46 bar

T2actual= -60 °C


79


N2 0,0046 473,07 2,17 3,14 0,014

CO2 0,0414 290,41 12,02 0,95 0,040

C1 0,8882 898,11 797,70 4,89 4,343

C2 0,0588 852,83 50,14 3,84 0,225

C3 0,0062 798,38 4,95 3,35 0,002

C4 0,0002 284,61 0,05 1,15 0,00023

C5 0 349,73 0 1,26 0

∑ / / 867,03 4,6242

867,03KJ/kg

4,6242KJ/Kg. °K

IV.7.3.8. Actual calculation of enthalpy, entropy output expander Liquid Phase:

P2=29,46 bar

T2actual= -60 °C


N2 0,0005 473,07 0,23 3,14 0,001

CO2 0,0785 290,41 22,79 0,95 0,074

C1 0,4227 898,11 379,63 4,89 2,067

C2 0,2782 384,9 107,08 2,03 0,564

C3 0,1573 354,85 55,81 1,83 0,287

C4 0,0185 284,61 52,65 1,15 0,021

C5 0,0109 394,73 4,30 1,26 0,013

∑ / / 622,49 / 3,027

622,49KJ/Kg


80

3,027KJ/Kg °K

849, 1052KJ/Kg

4,507KJ/Kg. °K

Actual enthalpy is:

69,3356KJ/Kg

The enthalpy isentropic is:

KJ/Kg

Performance computing expander:

.100

Entropy is:


81

0, 3368KJ/Kg°K

So the turbine work:

KJ/Kg

Actual work:

KJ/Kg

IV.8. INTERPRETATION OF RESULTS:

The adiabatic efficiency of turbine expansion is low from the mean value

and this shows that the machine operates in a value of the lower yield than the

manufacturer.

Changing parameters of pressure, temperature and the condensable fraction affect the

performance of the machine.

Conclusion

82

Conclusion

This work at the Central Production Facilities helped us to complete and consolidate our

theoretical knowledge with practical findings and manipulation on ground.

The obtained results confirm that the variation of the raw gas composition and the inlet pressure

are directly affecting the operating parameters.

Even this raw gas variation composition and the pressure affect the efficiency of the turbine

which the designer determine that the efficiency of the Expander is 85% meanwhile the real

efficiency we have calculated was 66,27 %.

Despite of this value is considered low when we compare it with the designer value, but the

Turbo-expander still one of the high technology used in industry.

The overall conclusion that emerges from this study shows that the Turbo-Expander is a vital

organ, which must give more attention to avoid stops that lead to a loss in appreciable quantities of

Liquefied Petroleum Gas and condensate; and therefore proposes the following recommendations:

Minimize disruptions Turbo-Expander except for maintenance reasons.

Do further study to calculate the parameters optimized operation of Turbo-Expander (P

& T) to enhance recovery of Liquefied Petroleum Gas and Condensate.

Do further study to optimize the injection of methanol at interchanges (G11-GA-32-201A

and B / GA-G11-32-202A and B) and Turbo-Expander to prevent icing.

Bibliographic

Bibliographic

[1] HADROUG, Y., "optimisation des parametres opératoires relatifs au

Turbo-Expander en vue de récupération le maximum des liquides"

Mémoire d'ingénieur, Direction Regionale de Gassi Touil, 2015.

[2] BENMESTFA, M ., " Etude Comparative d’une Détente Isenthalpique

et Isentropique et Influence sur la Récupération de GPL et Condensat"

Mémoire Fin de mise en situation professionnelle, Direction regionale de

gassi touil, 2014.

[3] GUEMGAM, ABD ELKADER., "Etude thérmodynamique sur le Turbo-

Expander au CPF", Mémoire d'ingénieur, Direction Regionale de Gassi

Touil, 2013.

[4] LAKHDARI, ABD ELATIF., " Etude Thermodynamique et Mécanique

du Turbo-Expander 01 EC 141 et Calcul du Rendement Actuel de La

Machine" Mémoire de fin de formation d’induction, 2013.

[5] MOHAMED, R M. BABAGHAYOU, M. GHOFRANE, M

ABDELMOUMEN "Etude Des Performances D'un Turbo-Expander"

Mémoire d'ingénieur, Université Saad Dhleb de Blida, 2006.

[6] BENSAHAD, ., "Présentation du nouveau projet de traitement de gaz

(CPF) à GTL", Rapport de stage, Direction Regionale de Gassi Touil,

2014.

[7] MANSOURI, ABD ELALI., " Etude mécanique d’un turbo-expander

ACMTC 727" Mémoire d'ingénieur, Direction Regionale de Gassi Touil

2014.

Abstract:

Through this work we have tried to study the performance of the Turbo-expander by using

analysis thermodynamic study of this machine, which is considered one of modern

technologies in the domain of industry, especially gas processing, because of high ability to

cooling until -61 ° C and therefore what is known as the process of Cryogenic, our study

were in an area called Central Production Facilities located in the Gassi Touil.

At last, after we calculate Enthalpy and Entropy of the components of the gas at Inlet and

Outlet of Expander by using a Thermoptim program, we were able to calculate the cost-

effectiveness of Turbo-expander, so we focused on the side Expander and corresponds result

is 66,27%.

Although the performance of the Expander is considered weak compared with what the

designer gave 85% but the Turbo-expander remains its use widely in the industrial domain.

Key words: Turbo-expander, Expander, Thermoptim, Gassi Touil, Cryogenic

:ملخص

رنك عه طشيق دساسح ذشمديىاميكيح نزي اآلنح انري ذعرثشمه Turbo-expanderمه خالل زا انعمم حانىا دساسح أداء

غايح ( قذسذ انعانيح عهى انرثشيذ إنىLPG and LNGانركىنخياخ انحذيثح في مدال انصىاعح, خاصح معاندح انغاص )

Central Productionحية ذمشزةضخ دساسةرىا فةي مىتدةح ذةذعى Cryogenicدسخةح مويةح, فيمةا يعةشـ ت ة -06

Facilities قاسي انتيم. في انري ذدع

ذخشج مىة Turbo-expanderفي األخيش, تعذما قمىا تحساب األورانثي األورشتي نمكواخ انغاص انمخرهفح انري ذذخم

ير, ندةذ زاوةد دساسةرىا مدرصةشج عهةى خاوةة ذمكىا مه حساب مشدد حي Thermoptimرنك تاسرعمال تشوامح يذعى

%66,27.زاود انىريدح انمرحصم عهيا فدط )انداوة انمخرص تانرثشيذ(, Expanderان

-Turboإال أن %85 ذعرثش ضويهح مداسوةح مةع قيمةح انمعتةاج مةه طةشـ انصةاوع Turbo-expanderتشغم أن مشدديح

expander .يثدى اسرعمان اسع في انمدال انصىاعي

انردميذانمرسع, انمرسع, ذشمتريم, قاسي انتيم, ذست :المفتاحية الكلمات

study the performance of turbo- expander (expander) · · 2016-12-14kasdi merbah university...

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