7/24/2014

Fasih Ahmed UNIVERSITY OF ENGINEERING AND TECHNOLOGY, TAXILA.

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Acknowledgement

I, Fasih Ahmed have completed my internship training at Pak Arab Fertilizer Limited (PFL),

Multan for a period of 4 weeks dated as 1-07-2014 to 29-07-2014 under the supervision of my

honourable mentors Miss Shereen Raza, Mr. Muhammad Aqeel, Mr. Mohtashim Ali, Mr.

Zubair and Mr. Hameed. I got all kind of help from my mentors and various working staff of

PFL in a very cooperative and professional environment. I really liked being a part of Pak Arab.

And lastly I would like to thank all the personal in the Ammonia Control Room who managed

to extract precious time for me and allowed me to learn so many new things that would help

me in my practical life.

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Table of Contents

1-Overview of ammonia plant--------------------------------------------------------------3

History of Ammonia Manufacture and Haber’s Process------------------------------3

Hydrogen Sources for making Ammonia-----------------------------------------------3

Sections of Ammonia Plant---------------------------------------------------------------3

2-Study of Piping and Instrument Diagrams (P&ID) of Ammonia Plant---------4

Definition of P&IDs------------------------------------------------------------------------4

Some of the Symbols used in P&IDs-----------------------------------------------------4

3- Functional Study of Ammonia Gas Compressors-----------------------------------4

4- Emergency Shutdown System (ESD) of Ammonia plant--------------------------5

5-Basics of annunciation System-----------------------------------------------------------5

Graphical Description of Relation between Alerts and Safety Related Alarms-----6

Alarms Set points and Presentation--------------------------------------------------------6

Alarm management improvement----------------------------------------------------------6

6- Study of Project implementation and basics------------------------------------------7

7- Study and listing of Project I/Os --------------------------------------------------------8

8-Introduction to RSLogix5000 for MicroLogix1100 and LogixPro Simulator---9

9-Study and Listing of Project BOM-------------------------------------------------------9

10-Appendix A----------------------------------------------------------------------------------10

11- References-----------------------------------------------------------------------------------11

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1. Brief Overview of Ammonia Plant

Ammonia plant was commissioned in 1976. The name plate capacity of ammonia plant

was 910 Tons per Day. In 1986 PGRU was installed & Plant’s capacity was increased to

960 Tons per Day. Ammonia plant installed in Pak Arab is designed by Kellogg

International Corporation.

2. History of Ammonia Manufacture and Haber’s Process

Ammonia is synthesized from Hydrogen and Nitrogen. When three moles of Hydrogen

react with one mole of nitrogen two moles of ammonia are formed. The source of nitrogen

is air as it is present in access in air and that of hydrogen can be varied but the common

source is from natural gas (CH4).

3H2 + N2 2NH3

Hydrogen Sources for making Ammonia.

Water electrolysis. (Relative Energy = 300%)

Coal Gasification. (Relative Energy = 175%)

Heavy fuel oil. (Relative Energy = 135%)

Naphtha reforming. (Relative Energy = 104%)

Natural gas reforming. (Relative Energy = 100%)

However the production of Hydrogen from natural gas requires less relative energy

consumption, that’s why this mode of production is preferred in PAK ARAB FERTILIZERS.

Sections of Ammonia (NH3) plant.

Desulphurization

High

Temperature

Shift

Secondary

Reforming

Hydrogenation

NH3 Synthesis

H2S Removal

Primary

Reforming

Gas Purification

Gas preparation

Synthesis

Converter

Synthesis Gas

Compressor

Methanation CO2 Removal

Low

Temperature

Shift

Refrigeration

Compressor

Ammonia Plant

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Study of Piping and Instrument Diagrams (P&ID) of Ammonia Plant.

Definition of P&ID:

A diagram which shows the interconnection of process equipment and the instrumentation used

to control the process. In the process industry, a standard set of symbols is used to prepare

drawings of processes. The instrument symbols used in these drawings are generally based on

International Society of Automation (ISA) Standard S5. 1.

Some of the Symbols used in P&IDs:

P B

1 5 1

HPdA

1 5 1

HTA

501

MICa

101

PI

133

101-J (Air gas compressors):

Studied various control signals as well as the annunciation equipment for 101-J compressors

such as PB-151, LPA- 152 and LLPA-155 etc.

105-J (Refrigerant Compressors):

Studied various control signals as well as the annunciators such as switches, alarms and wiring

by KIC. Some of the annunciation signals are PB-501, HTA-501 and HPdA-501 etc.

103-J (Syn. Gas Compressor):

Studied various control signals as well as the switches and necessary annunciators along with

the wiring by KIC.

Functional Study of Ammonia Gas Compressors.

The compressors installed at Ammonia Plant are axial compressors which involve dynamic

compression. Dynamic Compressors are those compressors in which a rotating mechanism is

produced to add velocity and pressure to the gas.

Compressors

Dynamic

Compressor

s

Positive

Displacement

Axial Centrifuge Reciprocating Rotary

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In Axial Compressors, gas flows parallel to the axis of rotation. There are two stages in the

axial compressors, a high stage and a low stage. A gear box links the high stage with the low

stage. It has a rotating component and a stationary component as well.

Rotating air foil is rotor.

Stationary air foil is stator.

Figure of Axial Compressor

Another Compressor that works on Dynamic Compression is Centrifuge compressor. Rotating

disk (impeller) forces gas to the rim of the impeller, increasing velocity.The diffuser converts

the velocity energy to pressure energy.

The details of the various compressors of ammonia are as follows:

101-J Air Compressor: - It has two stages, a high stage and a low stage as described above.

The turbine that drives the compressor is manufactured by AEG. The air compressor is used

compress air.

105-J Refrigeration compressor: - The construction and vendor of this compressor is same

as of 101-J. The refrigerator compressor is used to liquefy ammonia gas vapors.

103-J Syn.gas compressor: - The synthesis gas compressor is used to compress synthesis gas.

Emergency Shutdown System (ESD) of Ammonia plant.

In case of any fault and in order to protect the equipment and also to ensure the safety of the

workers a relay based emergency shutdown system commonly known as ESD is installed at

ammonia plant. It consists of approximately 150-200 relays operating at 110V AC.

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During my visit at the ammonia control room I studied the Relay Logic Diagrams for Ammonia

compressors.

Basics of Annunciation Systems.

The most common definition of an Annunciation Systems is “a signal designed to alert, inform,

guide or confirm deviations from acceptable system status.” Another common definition is that

an Annunciation system is designed to direct the operator’s attention toward significant aspects

of the current plant status. In other words, an Annunciation system should serve to help the

operator to manage his time. An Annunciation System consists of various annunciation

modules which give alarm and indicate the faulted section through lamps displayed on the

annunciation panel. The purpose of alarm systems is to alert operators to the plant conditions

that deviate from normal operating limits and thereby require timely action or assessment.

Graphical Description of Relation between Alerts and Safety Related

Alarms.

Normal Operating Range: - The range in which an equipment can be operated with safety and

without deviating from the desired set points is called as normal operating range.

Alerts/Condition monitoring: - Alerts are produced to indicate the operator if the process

variable is about to deviate from the set point.

Operator Alarm: - Operator alarm sounds when the process variable has reached beyond our

desired set point. Now the operator needs to make necessary steps in order to eliminate the

causes of the deviation.

Protective system: - Once the Operator alarm is sounded, to protect the equipment installed

the system needs to be shutdown.

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Alarms Set points and Presentation.

The type of alarm and its set point must be established to enable the operator to make the

necessary assessment and take the required timely action. Then alarm set points must be

documented and controlled in accordance with the alarm system management control. Timing

of alarms and potential operator reaction time are both critical.

The alarm interface provided for the operator must be effective. Alarms may be presented on

annunciation panels, individual indicators, CRT screens, or programmable display devices.

Alarms lists should be carefully designed to ensure that high priority alarms are readily noted

and recognized, while low priority alarms. A brief overview of the annunciation system is

described below using a graph.

Alerts can progress into alarms and eventually into safety shutdowns.

Alarm management improvement.

Following steps must be adopted in order to improve the alarm management (A.M) system.

Assessing the current alarm system performance.

Developing an A.M procedure document.

Analysing the alarm history.

Prioritizing the alarms.

Updating the alarms presentation techniques.

Auditing.

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Study of Project implementation of PLC based Annunciation System.

To Implement PLC based annunciation system which is to be replaced by annunciation

modules we have to consider the following steps which are as follows:

Study and listing of Project I/Os.

To replace the annunciators with Programmable Logic Controller (PLC) we must enlist the

Inputs and Outputs of the annunciator modules AU-105, AU-106 and AU-107 so that suitable

PLC can be selected for this purpose. I am enlisting the total I/Os as well as the individual

I/Os for the three compressors.

Table No: 1

S.NO TAG DESCRIPTION IO TYPE

1 ARPB ALARM RESET PUSH BUTTON DI

2 LTPB LAMP TEST PUSH BUTTON DI

3 AAPB ALARM ACCEPT PUSHBUTTON DI

4 FIL FAULT INDICATION LAMP DO

5 XA HORN DO

Table No: 2

Compressor Area DI DI Total DO DO Total

101-J 13+3 16 13+2 15

103-J 26+3 29 26+2 28

105-J 18+3 21 18+2 20

121-J

Project Implementation

I/O ListingSelect the

vendor and type of PLC

Logic And Graphics

DevelopmentListing of BOMTesting Training

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Total 66 63

20% Spare Points 13.2 12.6

Grand IO's Total for PLC 80 76

Now, Table 1 represents the some fixed number of inputs and outputs which are mandatory

for each compressor. The added spare points represents that in case of extension of the

system I/Os the PLC installed can easy accommodate it.

Introduction to RSlogix5000 and RSLogix Simulator.

As we have enlisted the I/Os for our project now is the time to select the suitable PLC for it

on the following basis:

Counts of I/Os.

How may analogue and digital I/Os are required.

Inventory optimization.

Inventory optimization means that we have to plan for long term future and system expansion

in order to install a PLC such that the system should not be overdesigned and under designed.

The PLC selected for this project has been manufactured by ALLEN BRADLEY and is named

as MICROLOGIX 1100. The software that is used to program this particular PLC is named

as RSLOGIX5000. RSLogix5000 is used for logic development whereas for graphics

development FACTORY TALK GATEWAY is used.

During my internship period I studied how to program a PLC using simple ladder logic

programming on LOGIXPRO simulator. This helped to enhance my skills in the field of PLC

programming.

Study and Listing of Project BOM

During my internship I studied the Bill of material (BOM) for PLC based annunciation

system and also studied about the material required along with their unit prises.

Note: BOM for the required project is mentioned in Appendix A.

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Appendix A

BOM For PLC Based Annunciation for Compressors Tag: 101-J/ 103-J/ 105J/ 121-J

S.No Item Quantity UOM Unit Price Total Price

1 MICROLOGIX 1100 PLC CONTROLLER 24VDC 6 EA 77,500 465,000

2 16 POINT 24VDC INPUT MODULE 9 EA 25,500 229,500

3 16 POINT 24VDC OUTPUT MODULE 9 EA 29,500 265,500

4 REDUNDENT POWER SUPPLY MODULE 110VAC TO 24VDC, 40A 4 EA 60,000 240,000

5 POWER SURGE PROTECTION DIODE, 40A 2 EA 17,000 34,000

6 Signal Conditioners 10 EA 160,000 1,600,000

7 LED Indications 700 EA 80 56,000

8 Interfacing relays,Barrier 160 EA 2,400 384,000

9 Terminal Block 600 EA 100 60,000

10 Wiring Cables 2 ROLL 2,000 4,000

11 Cable Ties 10 PKT 500 5,000

12 Lugs (U type) 10 PKT 500 5,000

13 Lugs (O type) 10 PKT 500 5,000

14 Lugs (I type) 10 PKT 500 5,000

15 PCV DUCT 1 EA 2,000 2,000

16 Cable Marking 1 EA 5,000 5,000

17 C-Channel /DIN Rail 3 EA 2,000 6,000

18 TRANSPARENT PLASTIC SHEET;SIZE:8'X4'X5MM 1 ROLL 10,000 10,000

Total PKR

3,381,000.00

G.S.T. (17%)

PKR 574,770.00

GRAND TOTAL

PKR 3,955,770.00

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References

1- Lessons In Industrial Instrumentation By Tony R. Kuphaldt Version 1.32 – Last

update April 1, 2013.

2- Process Control and Optimization by Béla G. Lipták.

3- WikiPedia.com

4- Honneywell.com

5- Rockwell automation.