steam piping in ammonia plant at nfcl

A study on steam piping in ammonia plant at nfcl

S.V.R.KUMARI

J.JHANSI ARUNA

G.V.V.R SRINIVAS

Neerukonda.NANI

Under The Guidance Of

Dr. D. S. V. PRASAD. Ph.D

Professor

Presentedby

ABSTRACT

This mini project work program has been under taken to investigate the

requirement of steam pipe lines in ammonia plant at “ NAGARJUNA

FERTILIZERS AND CHEMICALS LIMITED (NFCL) KAKINADA”. And to

study about the types of steams ,valves used in pipe lines , welding procedure of

pipe lines , working of steam pipe lines.

By following this process we can prevent leakages and damage of steam pipe lines

and also we can reduce corrosion by insulation process

INTRODUCTION

Nagarjuna fertilizers and chemicals Limited operates a large modern Ammonia urea

complex compromising two streams of ammonia and urea each.

The manufacturing facilities are located at Kakinada in the state of A.P. It is the first

gas based fertilizer complex in South India .

In NFCL the manufacturing urea for this the main raw material is liquid ammonia

by steam .Air from atmosphere comes in contact with the process gas from primary

reformer.

This plant had gone a major revamping in September 2009.The capacities are

enhanced to ammonia 2325 tones .

NFCL PROFILE

NAGARJUNA GROUP

PROJECT PROFILE

RAW MATERIAL

OBJECTIVES OF NFCL

A STUDY ON STEAM PIPING IN AMMONIA PLANT AT NFCL

In ammonia plant they are using three types of steams

Very high pressure steam(K.S) Pr:103kg / cm2 Temp:500ºc

High pressure steam (H.S) Pr: 37kg/cm2 Temp :370ºc

Low pressure steam(L.S) Pr: 3.5kg/cm2 Temp :145ºc

Generally the steam is produced in power plant in boilers, auxiliary boilers, waste heat

boilers (heat recovery steam generation units, HSRG) The piping for the steam is

according to the SNAMPROGRETTI‘s ITALY Specifications. Each line is designated

with specific number designating various features

Ex. 14”-11-K.S1100-88D-I.

It indicates

14”-size of pipe.

11-plant unit code

K.S – service of the pipe.

1100 -location.

88D- spec for pipe.

I –insulated..

Very High Pressure Steam:(KS)

In Ammonia Plant -1 approximately 240 t of KS is consumed. In this 20 t is imported

from Power plant and rest 220 t is produced in Ammonia plant itself by using primary

reformer’s waste heat. In emergencies KS is also let down to HS.

piping components Specifications

Pipe Line 10"Valve 2"VS01Orifice

Pressure Indicator(PI)

PI 003

Temperature Indicator (TI) TI 003

Control Valve HSV 003By Pass Valve 2”VD04Flow Transformer FT 003

Pressure Transformer 006

Temperature Indicator 006

Reducer 14”*10”Pipe Line 14”-11-KS1100-88D-I

Various piping components and specifications:

Non return valve

Pressure Design Of Piping Components

The required thickness of straight section of pipe shall be determined by

equation Tm=t + c

The minimum thickness T for pipe selected, considering, manufacture minus

tolerance than tm. Shall be not less than tm. The following nomenclatur is used in

equations for pressure design of straight pipe.

The thickness on steel pipes determined by the following formulas

tm= (8/7)*(PD/2Se+P)+c

8/7= (from I.B.R)

Where,

Tm=minimum wall thickness,

P=working pressure (max)

S=allowable stress

D=out side diameter of pipe

E=efficiency factory, 1 for seamless and erul pipes

C= corrosion allowance, 1mm.

NPS code(in) OD(mm) Thickness(mm)

Commercial

1/2” 21.3 3.22 Sch 160

1” 33.4 4.41 Sch 160

1-1/2” 48.3 5.87 Sch 160

2” 60.3 7.04 Sch 160

Pipe Sizes & Thickness Available Are:

Rating: 2500 LB RJ

(ringjoint gasket)

UNS Designation K 21590

Carbon 0.05-0.15

Manganese 0.30-0.60

Phosphorus Max 0.025

Max 0.025

Silicon 0.05 Max

Chromium 1.90-2.60

Molybdenum 0.87-1.13

Composition of K.S Pipe Material & Manufacture:

ASTM A 335 GRADE P22 SMLS +60637(I.B.R)

P22:

Insulation

Insulation is also followed according to snamprogetti’s specifications. The various letters

indicate the various types of insulations.

A=internally treated and externally coated line

B=line with externally coating only

E=electric traced line

F=cold insulated line (+5ºc to -273ºc)

I=hot insulated line (temp +6ºc and above)

N=non painted and non insulated line

S=internally treated and externally painted line

T=hot fluid traced line

V=line with external painting only

W=jacketed line

Each insulation is to be carried out according to their respective specification.

Ball Valve

WELDING SPECIFICATIONS

CONTENTS:

SCOPE AND FIELD OF APPLICATION:

This specification provides the requirements for chromium molybdenum steel

piping

PREPARATION FOR WELDING:

EDGE PREPARATION:

HOT ADJUSTMENT:

Temperature range from 700 to 950.all pieces having under gone hot adjustment

shall be subjected to PWHT.

WELDING PROCEDURE QUALIFICATIONS:

The welding procedure shall be previously qualified according to the

requirements of ASME.

PREHEATING:

It is required for any type of welding , including the welding of yokes,

tack welding, and the welding of permanent of temporary support.

ROOT PASS:

For but joint without back welding and for branch connections, the

root pass shall be performed with the welding process and the filler metal.

PWHT TREATMENTS:

The heating rate, measured at 100c intervals, shall not be higher than

200c/hr and difference measured by the various thermo couples shall never be higher

than 50c

HIGH PRESSURE STEAM (HS)

The HS lies in temperature of 370°c & a pressure of 37 kg/m^2. The Steam of this

network is coming from plant B.L &is utilized in Hydrolyzer 01-R—102. HS, there is no

import as HS is generated or extracted from DSTK 431/432 in Ammonia -1.(aprx.217 t).

•At ARC (AMMONIA REFRIGERATION COMPRESSOR) DSTK 451 IS 38tonnesper

hour.

•At PAC (PROCESS AIR COMPRESSOR) DSTK 421 is 28 tonnes per hour.

•Reformer is 101 tones.

Pipe class 65A

Pipe Material SMLS-ASTM A 335 GR.P1

Design pressure 44.00kg/cm^2

Design temperature 420°c=788°F

Allowable stress 13.60 KSI =956Kg/cm^2

Corrosion allowance 1.27

H.S Pipe Line Specifications

Pipe line: 24”-11-HS-1100-65A-I

We already know about 24, 11, HS, 1100, 65A, I

In detail about 65A SPEC:

Service: Steam condensate; Medium pressure steam (I.B.R) pipe size& thickness

available are as follows:

UNS Designation

K 11522

Carbon 0.10-0.20

Manganese 0.30-0.80

Phosphorus Max 0.025

Max 0.025

Silicon 0.10-0.50Chromium --

Molybdenum 0.44-0.65

Composition:

Pipe Line Material & Manufacture:

ASTM A 335 GRADE P1 SMLS +60637

P1:

LOW PRESSURE STEAM

The LS lie in temperature of 145°c and a pressure of 3.5kg/cm^2.

In LS there is no import and 15 tones of steam is produced.

Consumptions are 5 tones from GV section and 2 tones from deheater .

The export is 6 tones per hr.

From back pressure turbine - DSTP 710 A/B

DSTK 201/202

DSTK301/302

GATE VALVE

LS pipe line specification: pipe line 26”-11-LS-1100-11H-I

LS pipe material and manufacture:

ASTM A 106 GRADE B SMLS+60636

Properties : Tensile strength minimum

Yield strength minimum

Top ups:

Tapings:

Carbon maximum A - 0.30

Manganese - 0.29-1.06

Phosphorous maximum - -0.035

Sulphur maximum - 0.035

Silicon maximum - 0.10

Chrome maximum B - 0.40

Copper maximum B - 0.4

Molybdenum maximum - 0.15

Nickel maximum B - 0.4

Vanadium maximum B - 0.08

Chemical composition:

How to charge LS pipe line:

once MS header is charged. we can proceed with charging of LS header.

Turbine condenser vacuum system LS isolation values are closed.

Open all the utility points.

LS vent values PV-39 is open full by PIC-39on manual. open the isolated values.

Confirm P-110 is running and HW header is charged.

Now the LS header is ready for heating and charging.

Conclusion:

It is an esteemed privilege to do mini project in one of the reputed industry in south India (NAGARGUNA FERTILIZERS AND CHEMICALS LIMITED).

By this project we got an over view of steam piping network i.e. selection of valves, pipes & thickness, welding spec and how the mechanical equipment is being used.

By this process we can prevent leakages and damage of steam pipe lines and hence we can reduce corrosion by insulation process.

QUERY’S

Thank Q

steam piping in ammonia plant at nfcl

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