Fasih Ahmed completed a 4-week internship at Pak Arab Fertilizers Limited (PFL) where he studied the ammonia plant. He observed the piping and instrumentation diagrams to understand the plant sections and symbols. He examined the air, refrigerant and synthesis gas compressors which use dynamic compression. The plant has an emergency shutdown system and annunciation system to alert operators of deviations. Fasih proposed replacing the annunciator modules with a programmable logic controller and listed the input/outputs needed. He selected a MicroLogix 1100 PLC and studied programming in RSLogix5000 and LogixPro simulator.

1. 7/24/2014
Fasih Ahmed
UNIVERSITY OF ENGINEERING AND
TECHNOLOGY, TAXILA.

2. P a g e | 1
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.

3. P a g e | 2
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

4. P a g e | 3
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
MethanationCO2 Removal
Low
Temperature
Shift
Refrigeration
Compressor
Ammonia Plant

5. P a g e | 4
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

6. P a g e | 5
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.

7. P a g e | 6
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.

8. P a g e | 7
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.

9. P a g e | 8
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 Listing
Select the
vendor and
type of PLC
Logic And
Graphics
Development
Listing of BOMTestingTraining

10. P a g e | 9
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.

11. P a g e | 10
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

12. P a g e | 11
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.