dual pressure nitric acid process simulation results_prosim.pdf

8/14/2019 Dual Pressure Nitric Acid Process Simulation Results_ProSim.pdf

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Reader is reminded that this use case is only an example and should not be used for other purposes. Although this example is based on actual case itmay not be considered as typical nor are the data used always the most accurate available. ProSim shall have no responsibility or liability for damagesarising out of or related to the use of the results of calculations based on this example.

Copyright 2011 ProSim, Labge, France - Tous droits rservs www.prosim.net

P RO S IMP LUS HNO3 APPLICATION EXAMPLE

DUAL -P RESSURE NITRIC ACIDMANUFACTURING P ROCESS

INTEREST OF THIS EXAMPLE

This example corresponds to the simulation of a manufacturing unit of nitric acid by a dual-pressure process. It is a

rather traditional process of nitric acid industrial production. The main modules specific to the simulator ProSimPlus

HNO3 are implemented: absorption column of nitrous vapors, nitrous vapors condensers, oxidation reactors, heat

exchangers with oxidation volumes, nitrous vapor compressors, etc.

The particular points which are detailed in this example are:

The use of a constraint management module in order to reach a specification and the management of

information streams;

The use of an information stream to split a heat exchanger between a temperature set point and a simple

exchanger in order to avoid a stream recycling.

ACCESS Free-Internet Restricted to ProSim clients Restricted Confidential

CORRESPONDING P RO S IMP LUS HNO3 FILE HNO3 dual pressure process.pmp


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Dual-pressure nitric acid manufacturing process

Version : December 2011 Page : 2 / 25


TABLE OF CONTENTS

1. P ROCESS MODELING 3

1.1. Process description 3

1.2. Process flow diagram 5

1.3. Specifications 5

1.4. Components 6

1.5. Thermodynamic model 6

1.6. Operating conditions 7

1.7. "Hints and Tips" 13

1.7.1. Constra in ts and Recycles modules 13

1.7.2. Information stream handler module 14

1.7.3. Heat exchanger splitting 15

1.7.4. Changing of the thermodynamic model 15

2. RESULTS 16

2.1. Comments on results 16

2.2. Mass and energy balances 17

2.3. Column C101 profiles 22

2.4. Column C102 profiles 24

3. REFERENCES 25


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The process diagram is provided hereafter.

The liquid ammonia is vaporized by cooling water (E101), then heated (E102), filtered and sent in a mixer air-

ammonia (M101). The filtered atmospheric air is compressed (K101), then is divided into two currents, the primary

air (HP Air S2) which goes to the mixer air-ammonia (M101) and secondary air which goes to the bleacher (C102).

The air-ammonia mixture is directed towards the NH3 converter (R101).

The model of the reactor takes into account three reactions:

OH6NO4O5NH4 223

OH6N2O3NH4 2223

OH3ONO2NH2 2223

The gas after combustion contains nitrogen oxides, nitrogen and oxygen. Its significant heat content is recovered in

a series of exchangers (E107, E106, E108, E105, E109). After condensation (E110), a large quantity of acid with

weak concentration is formed and sent to the absorption tower (C101). The gas mixed with secondary air is

compressed (K102) and is cooled (E104 and E111). The gas and the acid are directed on the perforated plates of

the absorption column (C101) equipped in particular with cooling coils. Process water is introduced at the top and

the acid with the desired concentration is recovered at its bottom. This acid then goes to the bleaching column

(C102) equipped with plates. There is a stripping by secondary air (Air S2). The outgoing gases at the top of the

C101 absorber are sent in a series of gas-gas heat exchangers (E103, E104, E105 and E106), then in an expander

(T101) and finally in the stack.

In parallel, steam is produced by heat recovery. For that feed water is preheated (E109 and E108) then steam is

produced in the boiler (E112) and is overheated (E113). Part of this steam is turbinated (T102) to bring mechanical

power necessary to the process before being condensed (E114). For simplification purposes, that is not

represented on the diagram below, but in practice the two compressors (K101 and K102) are placed on the same

shaft as the turbines (T101 and T102).

The objective of this process is to produce 1.000 T/day of nitric acid (equivalent 100%) to a concentration of 58%

mass. The oxygen contents of tail gases are fixed at 2,5% in volume (mol.). The temperature at exit of the burner is

fixed at 890 C.

The process water feed flowrate, as well as the ammonia and air feed flowrates are automatically adjusted in order

to ensure this production.

On the level of the production of steam, the unit produces steam at 15 bars.


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1.2. Process flow diagram

Dual-pressure process flow diagram

1.3. Specifications

The specifications imposed on the process are as follows:

Production of 1000 Tons/day (equivalent 100%) of nitric acid with 58% mass.

Production of 30 bars steam

The oxygen content of tail gas is fixed at 2.5% in volume (mol.)

The temperature at the output of the burner is fixed at 890 C

Mechanical energy required by the two compressors for air (K101) and NOx (K102) is provided by the

turbines of tail gas (T101) and 30 bars steam (T102)

One also seeks to optimize the energy production by recoveries between hot streams and cold streams.


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1.4. Components

Properties of components involved in the simulation are taken from the specific HNO3 database, provided with

ProSimPlus HNO3 software. Nine components are taken into account:

Water (H 2O)

Nitric oxide (NO)

Nitrogen dioxide (NO 2)

Nitrogen Tetroxide (N 2O 4)

Nitrogen(N 2)

Oxygen (O 2) Nitric Acid (HNO 3)

Ammonia (NH 3)

Nitrous oxide (N 2O)

1.5. Thermodynamic model

For the main part of the process the thermodynamic model taken into account is the default model of the software

ProSimPlus HNO3 (see User's manual - chapter 2).

Two exceptions to that:

- at the level of the bleaching column, the model of Engels is used. Indeed, this model is particularly

adapted to the concentrated strong acids. Furthermore, this model must be modified in order to use

the same enthalpy basis as the HNO3 specific model :

H*=DH0f, ideal gas, 25C, 1 atm.

- at the level of the production of steam, a specific model for water and steam is used.


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1.6. Operating conditions

Process feeds

Am m oni a(NH3)

Air(LP A IR)

Process water(Water)

Water for s team(Water Utility S2)

Temperature (C) 10 25 20 20

Pressure (bar) 14 1 10 15

Total flow rate (t/d) Adjusted so as to satisfy

the specifications

Adjusted so as tosatisfy the

specifications

Adjusted so as tosatisfy the

specifications1 130

Reactor R101

Operat ing parameters Value

Type of reactor simple

Ammonia conversion rate (%) 5 O 2 + 4 NH 3 6 H 2O + 4 NO 96.2

3 O 2 + 4 NH 3 6 H 2O + 2N 2 3.7

2 O 2 + 2 NH 3 3 H 2O + N 2O 0.1

Pressure drop (bar) 0.05

Output temperature adiabatic

Heat exchangers

Name TypeOutput

te m per at u re ( C)Pressure drop

(bar)Oxidat ion

volume (m 3 )

E101 Cooler/Heater Dew temp. 8 -

E102 Cooler/Heater 80 0.05 -

E103a Cooler/Heater 70 0.05 -

E103b Simple heat exchanger - 0.05 -

E104a Cooler/Heater 125 0.05 1.8






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Condenser E111


Length of the tubes (m) 6

Number of tubes 250

Vapors flow Inside the tubes

Internal diameter of the tubes (mm) 25.4

Cooling water temperature (C) 15

Cooling water flow rate (t/d) 6 500

Flow direction Counter-current

Overall heat exchange coefficient (kcal/h/m 2/K) 600

Moreover, one adopts:

- the calculation of the oxidation reaction rate by the model of Koukolik- the calculation of the dimerization equilibrium constant by the model of Koukolik- the calculation of the constant of absorption of N 2O 4 in water by the method based on the

equation of Miller (bubble caps).

Compressor K101


Isentropic efficiency 0,845

Mechanical efficiency 1

Discharge pressure (bar) 4.6

Taking into account of the chemical reaction no

Compressor K102


Isentropic efficiency 0,795


Discharge pressure (bar) 10

Taking into account of the chemical reaction yes


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- the calculation of the oxidation reaction rate by the model of Koukolik- the calculation of the equilibrium constant for the N2O3 formation by the model of Miller.

Oxidation volumes

NomOxidat ion volume

(m 3 )P ressure drop

(bar)Temperature

(C)

O101 20 0.0125 Adiabatic



O104 20 0.0125 85


- a plug-flow pattern- an oxidation efficiency of 1- the calculation of the oxidation reaction rate by the model of Koukolik- the calculation of the dimerisation equilibrium constant by the model of Koukolik

Column C101


Type of column Plate oxido-absorption column

Number of stages 30

Weak acid feed stage 25(stages numbered from top to bottom)

Column diameter (m) 5

Diameter of the holes (mm) 5

Free section 4.82 %

Pressure drop in the column (bar) 0,8

Output temperature of the acid in the bottom (C) 25


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StageTemperature

C)Oxidat ion

volume (m 3 )Stage

Temperature

(C)Oxidat ion

volume (m 3 )

1 (top) 22 23.2 16 33 11.6

2 - 23.2 17 35 11.6

3 - 23.2 18 37 11.6

4 - 23.2 19 38 11.6

5 - 23.2 20 38 11.6

6 - 23.2 21 39 11.6

7 - 23.2 22 40 11.6

8 - 23.2 23 40 11.6

9 - 23.2 24 40 11.6

10 - 23.2 25 40 11.6

11 - 23.2 26 41 11.6

12 - 23.2 27 42 11.6

13 - 23.2 28 43 11.6

14 - 23.2 29 44 11.6

15 31 23.2 30 (bottom) 45 11.62


- the calculation of the temperature profile in the column from the provided temperatures- the dissolution of NOx is not taken into account and for NOx in liquid phase the oxidation of

NO is taken to 0%

- the calculation of the oxidation reaction rate by the model of Koukolik- the calculation of the dimerisation equilibrium constant by the model of Koukolik- the calculation of the equilibrium of the system nitrogen oxides water nitric acid by the

equation of Zhidkov

- the efficiency of oxidation of each plate is equal to 1- the hydrodynamic model on each plate is that of a plug-flow reactor

- the absorption efficiency on each plate is calculated by the equation of Atroshenko 3 with aheight of liquid on the trays of 10 cm.

Column C102


Type of column Absorber

Number of theoretical stages 5

Overhead pressure (bar) 4.2

Pressure drop in the column (bar) 0.2


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Pump P101


Exhaust pressure (bar) 11

Volumetric efficiency 0.65


Expander T101


Discharge pressure (bar) 1

Isentropic efficiency 0.83

Turbine T102


Discharge pressure (bar) 1.05

Isentropic efficiency 0.85

Valve V101

Operat ing parameters Value Com ments

Type of valve Three wayvalve

Splitting rate for the stream AIR HP2 (%) 80

This rate will be adjusted inorder to reach the specifications

Valve V102

Operat ing parameters Value Com ments

Type of valve Three wayvalve

Splitting rate of the streamSteam S5 (%) 90

This rate will be adjusted in order toexpand sufficient steam to balance the

power required by the compressors


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1.7. "Hints and Tips"

1.7.1. Constra in ts and Recycles modules

It is possible with ProSimPlus HNO3 to implement on the same flowsheet several modules of constraint

management. Here for example, for clarification of the diagram of simulation purposes, two modules of constraint

management are implemented:

- one for the process itself: SPEC01

- the other for the production of steam: SPEC02

The implementation of several modules of constraint management affects the order of calculation of the modules

(list of calculation automatically determined in ProSimPlus HNO3) and the convergence of each cycle, but does not

have any influence on the results obtained when convergence is reached. This possibility can be used in certain

very complex cases to facilitate convergence of flowsheets, or like here in order to simplify the representation of the

process.

The operation of the modules of Constraint Management in ProSimPlus HNO3 is described at the level of the user's

manual and illustrated in the application example of ProSimPlus E02 ( Cyclohexane Plant ).

In this case, at the level of the module SPEC01, 4 specifications (constraints) are imposed:

- the partial mass flowrate of pure nitric acid produced in bleaching column C102 bottom is fixed at

1000 T/d (measurement module MEAS03)

- the mass composition of the produced nitric acid (bleaching column C102 bottom) is fixed at 58%

(measurement module MEAS01)

- the oxygen volume composition (molar) in tail gas (TG S6) is fixed at 2.5% (measurement module

MEAS04)

- the output temperature of the reactor R101 (stream PG01) is fixed at 890C (measurement module

MEAS02)

With ProSimPlus HNO3, the module Constraint Management module SPEC01 then will adjust 4 parameterssimultaneously (action variables) to satisfy these specifications:

- ammonia feed flowrate (feed module NH3 feed )

- air feed flowrate (feed module Air feed )

- process water feed flowrate (feed module Process water feed )

- the value of the splitting ratio of the air in V101 valve between the air used the reactor R101 and the

air used in the bleaching column C102.

Moreover, this module SPEC01 also manages the convergence of the recycling streams.


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1.7.2. Information stream handler module

At the module of constraint management SPEC02 level, the turbinated steam flowrate is adjusted by action on the

opening of the valve V102, in order to balance the power consumption of the compressors K101 and K102 with thatproduced by the turbines T101 and T102. For that, several Information stream handler modules are implemented.

The Information stream handler module makes it possible in ProSimPlus HNO3 to make simple operations on a

information stream: to add (B) or of to withdraw (C) a constant, to multiply (A and P=1) or to divide (A and P=-1) its

content by a constant or to raise at power (P). The result of this operation is available in the information stream

leaving the Information stream handler module :

Output = A * (Input) P + B C

In this formulation, A, B, C and P are constants fixed by the user. Entering several information streams in a

Information stream handler module and exploiting their position in the parameter area of the module it is possible to

make them take the place of constant A, B, C and P and thus to make operations between several information

streams (see below).

While implementing several modules of this type it is thus possible to make more complicated operations. For more

complex calculations on the information streams it is however recommended to implement a Windows Script

module.

Here, the Information stream handler module H102 receives in entry:

- power of the K102 compressor as value to be handled (WK102)

- power of the K101 compressor as additive factor (B)

A and P are fixed at 1 and C at 0. Thus the leaving information stream ( Power compressors ) will contain the total

power consumed by the two compressors.

In the same way, the Information stream handler module H103 receives in entry:

- power produced by the T101 turbine as value to be handled (WT101)

- power produced by the T102 turbine as additive factor (B)

A and P are fixed at 1 and C at 0. Thus the leaving information stream ( Power turbines ) will contain the total power

produced by the two turbines.

These two information streams ( Power compressors and Power turbines ) are then sent towards the Information

stream handler module H104 to make the sum of them. The stream Power compressors as value to be handled

and the stream Power turbines as additive factor (B). A and P are fixed at 1 and C at 0. Thus the leaving information

stream ( Power difference ) will contain the difference between the power of the turbines (negative) and that of the

compressors (positive). This information stream Power difference is then sent towards the module SPEC02 which

will take in charge to make converge towards zero the value of Power difference by action on the rate of division of

the V102 valve.


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1.7.3. Heat exchanger splitting

In this example, most of the heat exchangers are simulated by uncoupling the hot stream and the cold stream. This

modeling of a heat exchanger between two streams makes it possible to avoid a recycling stream which wouldpenalize calculations by uncoupling the heat exchanger in two parts. This modeling is illustrated in the example of

application of ProSimPlus E02 ( Cyclohexane Plant ).

1.7.4. Changing of the thermodynamic model

In order of insure the consistency in the calculation of the enthalpies between the column C101 (oxido-absorption)

and the column C102 (bleacher) which are using different thermodynamic models (HNO3 specific for the first and

Engels for the latter), it is necessary to insert on the C102 inlet stream (Acid S1+S2) a dummy module which will

allow to change the thermodynamic model. The unit operation generally used for this purpose is a Cooler/Heater in

which the output temperature is taken equal to the inlet temperature. Thus only the enthalpy is recalculated. The

heat duty printed in the simulation report must be, of course, ignored as it corresponds only to the difference in the

enthalpies calculated by both models. In the present case, both models give enthalpy values which are very close

(deviation < 0.7 %), however this deviation must be multiplied by the value of the flowrate, that could lead, by the

end, to have some influence on the column C102.


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2. R ESULTS

2.1. Comments on results

The sequence of calculation (the order of calculation of the modules) is generated automatically. At the level of

recycling, no stream is initialized and ProSimPlus HNO3 chooses to make converge the stream Air S3.

The convergence of the first cycle is obtained in 4 iterations, that is to say 20 runs in the Maximum Cyclic Network.

The convergence of the second module of specification is obtained in 1 iteration, that is to say 4 passages in the

Maximum Cyclic Network.

When convergence is reached, the values obtained of the various parameters adjusted automatically by

ProSimPlus HNO3 to reach the specifications are as follows:

- ammonia feed flowrate: 283.616 t/d

- air feed flowrate: 4999.89 t/d

- process water feed flowrate: 367.240 t/d

- air splitting ratio in V101 valve:

air used in the R101 reactor: 83.83 %

air used in the C102 bleaching column: 16.17 %.

Regarding the absorption column (C101), convergence is obtained in 9 iterations, without any initialization.

Regarding the bleaching column (C102), it converges in 2 iterations, also without any initialization.


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2.2. Mass and energy balances

Streams Acid S1 Acid S1+S2 Acid S2 Acid S3 Acid S4From E111 Acids mixer C101 Dummy E110To Acids mixer Dummy Acids mixer C102 P01Partial flows t/d t/d t/d t/d t/dWATER 110.330629 719.0267179 608.696089 719.0267179 209.963131NITRIC OXIDE 0 0 0 0 0NITROGEN DIOXIDE 0 0.171242013 0.171242013 0.171242013 0NITROGENTETROXIDE

0 26.5555056 26.5555056 26.5555056 0

NITROGEN 0 0 0 0 0

OXYGEN 0 0 0 0 0NITRIC ACID 50.70934 1002.750981 952.0416409 1002.750981 48.4400512 AMMONIA 0 0 0 0 0NITROUS OXIDE 0 0 0 0 0Total flow t/d 161.039969 1748.504446 1587.464477 1748.504446 258.403182Total flow kmol/h 288.70913 2338.240064 2049.530933 2338.240064 517.643508Temperature C 91.9381166 52.59991071 45 52.59991071 81.6451604Pressure bar 9.89999732 9.899997325 9.899997325 9.899997325 4.21249886Enthalpic flow kcal/h -18692289.6 -143427975 -124735685 -142520016 -34196144.9Vapor fraction 0 0 0 0 0

Streams Acid S5 AIR S1 AIR S2 AIR S3 Condensates

From P01 V101 E103a C102 E114To C101 E103a C102 K102 >>>>Partial flows t/d t/d t/d t/d t/dWATER 209.963131 9.150953613 9.150953613 4.436011318 959.536085NITRIC OXIDE 0 0 0 0 0NITROGEN DIOXIDE 0 0 0 22.50500389 0NITROGENTETROXIDE

0 0 0 4.222192633 0

NITROGEN 0 613.4532114 613.4532114 613.2970848 0OXYGEN 0 186.0172684 186.0172684 185.7742049 0NITRIC ACID 48.4400512 0 0 2.755109167 0

AMMONIA 0 0 0 0 0NITROUS OXIDE 0 0 0 0 0Total flow t/d 258.403182 808.6214333 808.6214333 832.9896067 959.536085Total flow kmol/h 517.643508 1175.820719 1175.820719 1188.483363 2219.26197Temperature C 81.9068606 215.7343361 70 47.07917229 99.6325065Pressure bar 10.999997 4.599998757 4.54999877 4.199998865 0.99999973Enthalpic flow kcal/h -34193628.8 359264.567 -852795.401 -300693.485 1220318.93Vapor fraction 0 1 1 1 1


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Streams HP AIR1 HP AIR2 LP AIR NH3 NH3 S2From K101 V101 >>>> >>>> E101To V101 Mixer

Air+NH3K101 E101 E102

Partial flows t/d t/d t/d t/d t/dWATER 56.5824732 47.43151958 56.5824732 0 0NITRIC OXIDE 0 0 0 0 0NITROGEN DIOXIDE 0 0 0 0 0NITROGENTETROXIDE

0 0 0 0 0

NITROGEN 3793.12379 3179.670583 3793.123794 0 0OXYGEN 1150.18801 964.1707389 1150.188007 0 0NITRIC ACID 0 0 0 0 0

AMMONIA 0 0 0 283.6165392 283.616539NITROUS OXIDE 0 0 0 0 0Total flow t/d 4999.89427 4191.272841 4999.894275 283.6165392 283.616539Total flow kmol/h 7270.37281 6094.552088 7270.372806 693.8895752 693.889575Temperature C 215.734336 215.7343361 25 10 9.36352185Pressure bar 4.59999876 4.599998757 0.992984732 13.99999622 5.99999838Enthalpic flow kcal/h 2221416.32 1862151.757 -7563428.45 -11101866.5 -7703546.38Vapor fraction 1 1 1 0 1

Streams NH3 S3 Nitric AcidProduction

PG00 PG01 PG02

From E102 MEAS03 Mixer Air+NH3

MEAS02 E107

To Mixer Air+NH3

>>>> R101 E107 E106a

Partial flows t/d t/d t/d t/d t/dWATER 0 723.7416218 47.43151958 497.4541587 497.454159NITRIC OXIDE 0 0 0 480.7134005 480.713401NITROGEN DIOXIDE 0 0.000204006 0 0 0NITROGEN

TETROXIDE

0 0 0 0 0

NITROGEN 0 0.155163048 3179.670583 3188.301177 3188.30118OXYGEN 0 0.242766129 964.1707389 308.053362 308.053362NITRIC ACID 0 999.9960371 0 0 0

AMMONIA 283.616539 0 283.6165392 0 0NITROUS OXIDE 0 0 0 0.36648111 0.36648111Total flow t/d 283.616539 1724.135792 4474.889381 4474.88858 4474.88858Total flow kmol/h 693.889575 2335.689738 6788.441663 6961.740584 6961.74058Temperature C 80 51.93127648 198.0812614 889.9999211 440Pressure bar 5.94999839 4.399998811 4.599998757 4.54999877 4.49999878Enthalpic flow kcal/h -7280058.65 -143072111 -5417906.89 -5417908.71 -30796025.4Vapor fraction 1 0 1 1 1


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Streams PG03 PG04 PG05 PG06 PG07From E106a O101 E108a O102 E105aTo O101 E108a O102 E105a OXI 03Partial flows t/d t/d t/d t/d t/dWATER 497.454159 497.4541587 497.4541587 497.4541587 497.454159NITRIC OXIDE 471.416336 376.4039363 368.8073881 282.2212567 277.264103NITROGEN DIOXIDE 14.2542765 159.9260257 171.5512153 304.2980458 311.662956NITROGENTETROXIDE

2.8829E-05 0.001757513 0.02363313 0.0310847 0.2665072

NITROGEN 3188.30118 3188.301177 3188.301177 3188.301177 3188.30118OXYGEN 303.096121 252.435043 248.3845261 202.2163753 199.573196NITRIC ACID 0 0 0 0 0

AMMONIA 0 0 0 0 0NITROUS OXIDE 0.36648111 0.36648111 0.36648111 0.36648111 0.36648111Total flow t/d 4474.88858 4474.88858 4474.88858 4474.88858 4474.88858Total flow kmol/h 6955.28559 6889.317386 6884.033172 6823.912763 6820.36439Temperature C 290 325.3800873 220 252.7245814 180Pressure bar 4.4499988 4.437498801 4.387498814 4.374998818 4.32499883Enthalpic flow kcal/h -38871910.2 -38871910.2 -44442115.9 -44442115.9 -48230234.8Vapor fraction 1 1 1 1 1

Streams PG08 PG09 PG10 PG11 PG13From OXI 03 E109a E110 O104 K102To E109a E110 O104 K102 E104aPartial flows t/d t/d t/d t/d t/dWATER 497.454159 497.4541587 280.5665562 280.5665562 285.002567NITRIC OXIDE 228.148186 223.6229539 222.0586562 150.6022616 150.602262NITROGEN DIOXIDE 387.010908 387.5943842 338.5782304 439.0036651 496.534591NITROGENTETROXIDE

0.22332033 6.57795939 22.62660588 31.75847658 0.95470962

NITROGEN 3188.30118 3188.301177 3188.301177 3188.301177 3801.59826OXYGEN 173.384348 170.9714722 163.9877533 125.8868524 311.661057

NITRIC ACID 0 0 0 0 2.75510917 AMMONIA 0 0 0 0 0NITROUS OXIDE 0.36648111 0.36648111 0.36648111 0.36648111 0.36648111Total flow t/d 4474.88858 4474.888587 4216.48546 4216.48547 5049.47504Total flow kmol/h 6786.2826 6780.263058 6230.243037 6176.495317 7380.83997Temperature C 198.72224 110 81.64516041 85 192.339758Pressure bar 4.31249883 4.262498848 4.212498862 4.199998865 9.9999973Enthalpic flow kcal/h -48230234.8 -52799109.1 -25845022.8 -27112834.5 -21102233.3Vapor fraction 1 1 1 1 1


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Streams PG14 PG15 Steam S1 Steam S2 Steam S3From E104a E111 E112 E113 V102To E111 C101 E113 V102 T102Partial flows t/d t/d t/d t/d t/dWATER 285.002567 167.4230739 1130 1130 959.536085NITRIC OXIDE 123.490504 119.2119249 0 0 0NITROGEN DIOXIDE 525.913527 458.7435962 0 0 0NITROGENTETROXIDE

13.1436659 49.85086208 0 0 0

NITROGEN 3801.59826 3801.598262 0 0 0OXYGEN 297.204935 288.4858539 0 0 0NITRIC ACID 2.75510917 2.755109167 0 0 0

AMMONIA 0 0 0 0 0NITROUS OXIDE 0.36648111 0.36648111 0 0 0Total flow t/d 5049.47505 4888.435163 1130 1130 959.536085Total flow kmol/h 7356.4965 7023.045811 2613.519249 2613.519249 2219.26197Temperature C 125 91.93811658 197.8505116 393.1981727 393.198173Pressure bar 9.94999731 9.899997325 14.84999599 14.799996 14.799996Enthalpic flow kcal/h -25332332.1 -12128773.1 2743214.284 7808092.881 6630218.48Vapor fraction 1 1 1 1 1

Streams Steam S4 Steam S5 TG S1 TG S2 TG S3From T102 V102 C101 E103b E104bTo E114 >>>> E103b E104b E105bPartial flows t/d t/d t/d t/d t/dWATER 959.536085 170.4639145 7.154859967 7.154859967 7.15485997NITRIC OXIDE 0 0 2.334332508 2.334332508 2.33433251NITROGEN DIOXIDE 0 0 3.129031469 3.323380347 3.35275238NITROGENTETROXIDE

0 0 0.223896879 0.029547791 0.00017573

NITROGEN 0 0 3801.598262 3801.598262 3801.59826OXYGEN 0 0 111.7994054 111.7994054 111.799405

NITRIC ACID 0 0 0.000525795 0.000525795 0.00052579 AMMONIA 0 0 0 0 0NITROUS OXIDE 0 0 0.36648111 0.36648111 0.36648111Total flow t/d 959.536085 170.4639145 3926.606795 3926.606795 3926.60679Total flow kmol/h 2219.26197 394.257276 5823.063828 5823.151838 5823.16514Temperature C 128.789291 393.1981727 22 51.83759596 155.728602Pressure bar 1.04999972 14.799996 9.099997541 9.049997554 8.99999757Enthalpic flow kcal/h 1777553.49 1177874.405 -978694.335 233365.6391 4463464.37Vapor fraction 1 1 1 1 1


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Streams TG S4 TG S5 TG S6 Water Water UtilityS2

From E105b E106b MEAS04 >>>> >>>>To E106b T101 >>>> C101 E109bPartial flows t/d t/d t/d t/d t/dWATER 7.15485997 7.154859967 7.154859967 367.2407048 1130NITRIC OXIDE 2.33433251 2.334332508 2.334332508 0 0NITROGEN DIOXIDE 3.35291791 3.352927815 3.352927815 0 0NITROGENTETROXIDE

1.0196E-05 2.89804E-07 2.89804E-07 0 0

NITROGEN 3801.59826 3801.598262 3801.598262 0 0OXYGEN 111.799405 111.7994054 111.7994054 0 0NITRIC ACID 0.00052579 0.000525795 0.000525795 0 0

AMMONIA 0 0 0 0 0NITROUS OXIDE 0.36648111 0.36648111 0.36648111 0 0Total flow t/d 3926.60679 3926.606795 3926.606795 367.2407048 1130Total flow kmol/h 5823.16521 5823.165218 5823.165218 849.3722577 2613.51925Temperature C 247.85697 439.3442294 171.0302931 20 20Pressure bar 8.94999758 8.899997595 0.99999973 9.999997298 14.9999959Enthalpic flow kcal/h 8251581.95 16327464.53 5089518.327 -58071654.3 -27707366.3Vapor fraction 1 1 1 0 0

Streams Water UtilityS3

Water utilityS4

From E109b E108bTo E108b E112Partial flows t/d t/dWATER 1130 1130NITRIC OXIDE 0 0NITROGEN DIOXIDE 0 0NITROGENTETROXIDE

0 0

NITROGEN 0 0OXYGEN 0 0NITRIC ACID 0 0

AMMONIA 0 0NITROUS OXIDE 0 0Total flow t/d 1130 1130Total flow kmol/h 2613.51925 2613.519249Temperature C 116.833991 198.0095633Pressure bar 14.949996 14.89999597Enthalpic flow kcal/h -23138491.9 -17568286.2Vapor fraction 0 0.07331793


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2.3. Column C101 profiles

-1.1E+07

-1.0E+07

-9.0E+06

-8.0E+06

-7.0E+06

-6.0E+06

-5.0E+06

-4.0E+06

-3.0E+06

-2.0E+06

-1.0E+06

0.0E+001 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

H e a

t d u

t y ( k c a

l / h )

Tray

Heat duty

0

100

200

300

400

500

600

700

800

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

N O x m a s s

f l o w r a

t e s

( t / d )

Tray

NOx vapor mass flowra tes

NO NO2 N2O4 NOx (NO+NO2+2N2O4)


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0

10000

20000

30000

40000

50000

60000

70000

80000

90000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

N O x a m o u n

t ( p p m v

)

Tray

Amount of NOx amount (ppmv)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

M a s s

f r a c

t i o n

Tray

Liquid mass fractions

HNO3 NOx


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2.4. Column C102 profiles

0.40

0.42

0.44

0.46

0.48

0.50

0.52

0.54

0.56

0.58

0.60

1 2 3 4 5

M a s s - f r a c

t i o n

Stage

Liquid mass-fractions

WATER NITRIC ACID

0.000

0.005

0.010

0.015

0.020

0.025

0.030

1 2 3 4 5

M a s s - f r a c

t i o n

Stage

Vapor mass-fractions

NITROGEN DIOXIDE NITROGEN TETROXI


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3. R EFERENCES

[1] Badoual C. Acide Nitrique

Techniques de l'Ingnieur, trait de Gnie des Procds

[2] Clarke Stephen I. and Mazzafro William J.

Nitric Acid

Kirk-Othmer Encyclopedia of Chemical Technology, 4th edition

[3] Joulia X.

"Contribution au dveloppement d'un programme gnral de simulation. Application l'analyse du

fonctionnement d'un atelier de production d'acide nitrique"

Thse INPT 1981

dual pressure nitric acid process simulation results_prosim.pdf

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