1. INTERNSHIP REPORT
PREPARED BY: ZEESHAN AHMED (CH-038)
SHARJEEL ZAHEER(CH-055)
DEPARTMENT: CHEMICAL ENGINEERING
(THIRD YEAR)
24-05-2012 TO 23-06-2012
1

2. INDEX
S.NO. CONTENTS
PAGE NO.
1
INTRODUCTION TO NOVATEX
3
2 GROUP PRODUCTS 4
3 MONOMERS AND POLYMERS 5
4 PPLYMERISATION 6
5 INTRODUCTION TO PET 7
6 HSE (HEALTH AND SAFETY ENVIRONMENT ) 8
7 POLY CONDENSATION II 10
8 BATCH PREPARATION 13
9 FILTER CLEANING AREA 19
10 FURNACE 21
11 SSP (SOLID STATE POLYMERIZATION) 23
12 NITROGEN PURIFICATION SYSTEM 26
13 UTILITY 29
14 LABORATORY 37
2

3. INTRODUCTION
Gatron (Industries) Ltd. and Novatex Limited belong to a group of
companies, G&T – Gani & Tayub. The group is in business since
1948. These five decades of operational excellence, experience
and expertise have all formed a combined strength to empower
the group as a leading name in fashion garments (BONANZA),
Synthetic Textiles, Polyester Filament Yarn, Polyester Chips and
PET Resin in Pakistan. The group employs more than 6,000
people in the country.
 Novatex Limited {along with Gatron (Industries) Limited} is
the only PET Resin Bottle Grade manufacturer in Pakistan,
with the brand name of "Gatronova."

 Novatex produces PET Resin for Domestic & Export sales.

 Gatron produces PET Resin for in-house use in the
manufacturing of PET Preforms.

 The Group is in Polymer production since 1988 and in PET
Resin production since 1998.

 The total PET resin production capacity is 235,000
mt/annum, out of which more than 70% of the quantity is
available for export.

 Certified to meet FDA & EEC standards.
 Suitable for all applications of PET, including sheet.
 Widely approved by major CSD and Mineral water brands in
the World.
3

4.  Used by customers in more than 45 countries with major
quantities going to Western Europe.
 Fast Reheat resin is also available.
 With the advantage of regular in-house testing on both
injection molding and blow molding machines, Gatronova
has the advantage of utilizing this complete loop to
continuously optimize it's quality.

 Capacity to produce over 1.5 billion preforms per year. The
PET Resin (raw material) for these preforms is produced in-
house by Gatron and Novatex and therefore gives standardized
& consistent preforms.
 Sizes range from 13 gms to 55 gms, with neck sizes 28 mm
PCO / BPF & 30/25, for 330ml to 2250 ml Water / CSD bottles.
 Produced on Husky HyPET & G-Line Machines mainly installed
after 2004.
 Nearly half of the perform production is exported.
 Preforms are tested not only in the laboratory but also by actual
blowing into bottles on regular basis. So, quality of preforms is
also monitored in actual use.
GROUP PRODUCTS
PET Resin Bottle Grade
PET Preforms for Bottles
PET Bottles
Polyester Chips Textile Grade
4

5. Polyester Filament Yarn
Warp Knit & Raschel Fabrics
Curtains
Ready-Made Garments
Scarves
Bed Linen
Home Textiles
Circular & Flat Knit Fabrics
Woven Fabrics on Shuttle-Less Looms
MONOMERS AND POLYMER
Monomers are the building blocks of more complex molecules, called
polymers. Polymers consist of repeating molecular units which usually
are joined by covalent bonds.
Monomers
Monomers are small molecules which may be joined together in a repeating
fashion to form more complex molecules called polymers.
Polymers
A polymer may be a natural or synthetic macromolecule comprised of
repeating units of a smaller molecule (monomers). While many people
use the term 'polymer' and 'plastic' interchangeably, polymers are a much
larger class of molecules which includes plastics, plus many other
materials, such as as cellulose, amber, and natural rubber.
Examples of Polymers
5

6. Examples of polymers include plastics such as polyethylene, silicones such
as silly putty, biopolymers such as cellulose and DNA, natural polymers
such as rubber and shellac, and many other important macromolecules.
POLYMERIZATION
Polymerization The process by which monomers are transformed into
polymers is called polymerization.
Polymers are macro-sized molecules of relatively high molecular mass,
which find extensive use in our daily life.
Polymers are large but single chain-like molecules in which the repeating
unit derived from small molecules called monomers are covalently
linked. Structurally, they are characterized by many repeating
molecular units which form linear chains or a cross-linked network.
Common examples of materials made from polymers are plastic dishes,
cups, non-stick pans, automobile tyres, plastic bags, rain coats, television
and computer cabinets, flooring materials and materials for biomedical
and surgical operations.
ADDITION POLYMERIZATION
Definition: A chemical reaction in which simple molecules (monomers) are
added to each other to form long-chain molecules (polymers) without
by-products. The molecules of the monomer join together to form a
polymeric product in which the molecular formula of the repeating unit
is identical with that of the monomer. The molecular weight of the
polymer so formed is thus the total of the molecular weights of all of the
combined monomer units.
CONDENSATION POLYMERISATION
6

7. Condensation polymerisation is when two molecules of the same substance
(monomer) react together to form polymer chain (like polythene) and
eliminate a smaller (usually water) molecule.
For example, Nylon-6 is prepared by using condensation polymerisation of
ε-Caprolactum
An Introduction to PET
(Polyethylene terephthalate)
PET (also abbreviated PETE) is short for polyethylene terephthalate, the
chemical name for polyester.
PET is a clear, strong, and lightweight plastic that is widely used for
packaging foods and beverages, especially convenience-sized soft drinks,
juices and water. Virtually all single-serving and 2-liter bottles of carbonated
soft drinks and water sold in the U.S. are made from PET.
It is also popular for packaging salad dressings, peanut butter, cooking oils,
mouthwash, shampoo, liquid hand soap, window cleaner, even tennis balls.
Special grades of PET are used for carry-home food containers and prepared
food trays that can be warmed in the oven or microwave.
The basic building blocks of PET are ethylene glycol and terephthalic acid,
which are combined to form a polymer chain. The resulting spaghetti-like
strands of PET are extruded, quickly cooled, and cut into small pellets. The
resin pellets are then heated to a molten liquid that can be easily extruded or
molded into items of practically any shape.
PET was first synthesized in North America in the mid-1940s by Dupont
chemists searching for new synthetic fibers. Dupont later branded its PET
fiber as “Dacron.” Today, more than half of the world’s synthetic fiber is
made from PET, which is called “polyester” when used for fiber or fabric
applications. When used for containers and other purposes, it is called PET
or PET resin.
7

8. In the late 1950s, researchers found a way to stretch a thin extruded sheet of
PET in two directions to create PET film, which is now used extensively for
video, photo and packaging films. In the early 1970s, the technology was
developed for blow-stretch molding PET into bottles. The PET bottle was
patented in 1973.
HSE (HEALTH AND SAFETY
ENVIRONMENT)
SAFETY CONCEPTS:
HEALTH AND SAFETY:
HAZARD:
RISK:
CONTROL MEASURE:
ACCIDENTS:
INCIDENTS:
NEAR MISS:
UNSAFE ACT:
UNSAFE CONDITIONS:
LOCKOUT/TAGOUT:
TRIANGLE OF FIRE:
There are three things need for fire.
1. Heat
2. Air
3. Fuel
PRINCIPLES OF FIRE:
• STARVATION:
When we remove fuel from the fire then this is known as
“starvation”.
• SMOOTHERING:
When we remove air from the fire then this is known as “smothering
”.
8

9. • COOLING:
When we remove heat from the fire then this is known as “cooling”.
CLASS OF FIRE:
There are four classes of fire.
A class fire:
Fire of the wood.
Water is use to remove this fire.
B class fire:
Fire of the liquids, liquids like oil, paints etc.
Foams is use to remove this fire.
C class fire:
Energized electrical appliances.
CO2 is use to remove this fire.
D class fire:
Fire of the metals.
Dry chemicals is use to remove this fire.
Water is not use for metal fire because metals have very high temperature
about 1000 °C and water boils at 100 °C so when water boils hydrogen and
oxygen produce and oxygen increases the fire.
PASS TECHNIQUE :
Pass technique is use to remove the fire.
P: pull the pin
9

10. A: aim the nozzle
S: squeeze the level
S: sweep side by side
• In fire extinguisher if needle on the red it means it can not use but if
the needle is on yellow or green then it can be use.
• CO2 extinguisher has a big discharge nozzle and has not any meter.
• 16 is the telephone number for fire brigade.
Q: what should you do in case of fire?
1. Raise the fire alarm and shout fire, fire , fire
2. Telephone (16) for fire brigade.
3. Fire extinguisher/ fire hydrant
POLY CONDENSTION II
RAW MATERIALS SPECIFICATIONS:
PTA (PURE TYEREPHTHALIC ACID)
M.WT:166.13
Appearance: white powder
Water content: ≤0.3wt%
Mean particle size: 115-135 micro meters
Melting point: 300 C
10

11. MEG (MONO ETHYLENE GLYCOL):
M.wt:62.07 g/mol
Appearance: colorless transparent liquid
DEG: ≤0.05wt%
Density (20C): 115.1-115.6 kg/m3
Melting point: -13 C
Boiling point: 197.6 C
ADDITIVES :
BLUE TONOR:
Its chemical name is classified. However it is a form of dispersed dye. Its
function is to keep PET B value below 1.if the value gets more than 1,
chips appear to be yellow.
RED TONOR(COBALT ACETATE):
m.wt:249.08 g/mol
Appearance: dark purple red solid
Melting point: 100C
Specific gravity: 1.705
DEG
11

12. M. wt: 106.12
Appearance: colorless liquid
Melting point: -8C
Boiling point: 245.8C
H3PO4 (PHOSPHORIC ACID):
Appearance: colorless viscous liquid
Boiling point: 158C
Specific gravity: 1.685 @ 25C
Melting point: 21C
IPA (ISO PHTHALIC ACID):
M.wt:166.1
Appearance: white powder
Water content: : ≤0.2wt%
Melting point: 345 C-348 C
12

13. CATALYST:
CAT (NORM): ANTIMONY TRI ACETATE
Appearance: white crystal powder
Specific gravity: 1.22
Solubility @ 20C: soluble in EG to clear solution
BATCH PREPARATIOIN
CAT (NOR) BATCH RECIPIE:
Conc.: 1.8%
Total EG taken: 6615 kg
Total amount of catalyst (antimony tri acetate):135 kg
Temperature: 60C
Sample collection time: after 1 hour of batch completion
Lab result: 7200 ppm to 7800ppm
CAT(Co) RED TONER BATCH RECIPIE:
Conc.:0.600%
Total EG taken: 2940kg
Total amount of catalyst (antimony tri acetate):60kg
Total amount of cobalt acetate: 20kg
Temperature: 60C
Sample collection time: after 1 hour of batch completion
Lab result: 7100ppm to 7600 ppm
H3PO4 (PHOSPHORIC ACID) BATCH RECIPIE:
Conc.:0.85%
Total EG taken: 4126kg
13

14. Total amount of H3PO4 : 42.75kg
Sample collection time: after 4 hours of batch completion
Lab result: 0.80% to 0.95%
BLUE TONER BATCH RECIPIE:
Conc.:0.0084%
Total EG taken: 3200kg
Total amount of blue toner: 300 g
Sample collection time: after 4 hours of batch completion
Lab result: 22% to 30%
PROCESS:-
PASTE PREPALATION VESSEL:-(11 TA-01)
The key point of paste preparation process is to ensure definite ratio of
EG/PTA & IPA in 11-TA01 so that it is required to feed PTA,EG,IPA
and the catalyst, and the additives solution in accordance with the set
ratio.
PTA and IPA is tipped into the paste preparation vessel in which IPA is
20kg and PTA is 840kg at the ratio of 0.023, where agitation is done to
form a fine paste. Different additives are also tipped into this except
H3PO4,it is fed into the esterification 2 reactor (13R01). Nitrogen gas is
also passed through this vessel so as PTA can’t stick with each other to
form lumps. Two pumps use to transfer the paste into 13R01.two sets of
paste pumps 11-P01 ½ are installed. the capacity of each pump should
meet the requirement of the whole load of the line. during normal
operations two sets of pumps are in operation but if there is something
wrong with one of them another pump shall take over the whole load.
ESTERIFICATION 1:-(12-RO1)
The paste which is formed is pumped to the first reactor. It is basically the
continuous stirred tank reactor having a temperature of 260˚C.
14

15. In this reactor, the two heating material is used to give an appropriate
temperature to the paste or a material present in it. One is the sandotherm
present in liquid form in the coils and the other is the dowtherm present in
vapors from in the jacket. Agitation is done in all the reactors to convert in
monomers.
ESTERIFICATION 2:-(13-R01)
The purpose of this reactor is same as the first reactor that is to increase
the intrinsic viscosity by agitation. The temperature of this reactor
267˚c.it is also the continuous stirred tank reactor.the conversion is
96.5%.
COLUMN:-(13C01)
After passing through two reactor’s the vapors of EG as well as water is
then fed into the column in which the temp of bottom is at about 180˚c,
so water vapors go up in the column with very small amount of EG .by
showering of EG liquid, the vapors of EG condensed and go down and
water vapors is condensed by off gas sprinkling tower so as to remove
contents of aldehyde.
TOP VAPOR FRACTION TO CONDENSER
15
FEED
REFLUX
VAPORS

16. It is controlled that EG content in water at top of column is less then 0.5
wt % and water content in EG in bottom of column is less then 1.5%,
PRE POLY- CONDENSATION 1: (14-R01)
The product is fed into the chamber of 14R01 from 13R01 due
to pressure difference. This is basically the plug flow type reactor
at a temperature of 277.5 degree centigrade. 14R01 is in vacuum
condition. The purpose of vacuum is to decrease B.P of a mixture
so as to separate vapors of water and E.G immediately and easily.
E.G produce in poly condensation reaction and water produce in
esterifIcation reaction are evaporated at a very high speed so
product is mixed completely and it is not necessary to install an
agitator in the reactor. The HTM is used for heating inner coils as
well as jacket. The intrinsic viscosity of 14R01 at the outlet is 0.13.
SCRAPPER CONDENSOR: (14-E01)
Mixed vapor of E.G and water is fed into the scrapper condenser
from 14R01 and contact with spray E.G in opposite direction. The
most of E.G and a part of water in vapor will be condensed. The
vapors of E.G and water that coming from 14R01 having some
amount of oligomers vapors which is then converted into solid after
being contact with spray E.G and then blocked the line that's why we
use scrapper condenser that scraps these solid oligomers.
PRE POLY-CONDENSATION 2: (15-R01)
Material flows from 14-R01 into 15-R01 under pressure difference.
15R01 is horizontal reactor with disc rings. Material between two
discs is mixed completely by the rotating disc. This is disc ring reactor
having the temperature of 282.4 degree centigrade. 15R01 is
equivalent to a series of completely mixed reactor in function so that
reaction in the reactor is increased. The intrinsic viscosity at the outlet
is ranging from 0.25 to 0.30. The revolution of a disc is controlled by
16

17. an inverter.
SCRAPPER CONDENSOR: (15-E01)
The vapors of E.G and water from 15-
R01 is condensed by contact with spray E.G in adverse current. This
is same as 14-E01.
FILTER: (16-F01)
The material is then fed into the filter where the dust and
impurities separated out to ensure the purity of the material. The size
of 16F01 is 100 micron and has 70 candles.
DISC RING REACTOR: (17-R01)
Final poly condensation reactor
17R01 is a horizontal reactor with disc rotor and driven by a double
shaft. HTM vapors is present in the jacket to melt the polymer that
stick with wall as the material is so viscous as well as to maintain the
temperature of the reactor at 283.5 degree centigrade. The purpose
of using disc ring reactor is to mix the material as we know that the
mixture is highly viscous that agitator can't do this operation.
SCRAPPER CONDENSOR: (17-E01)
The vapors of E.G and water is fed
into 17E01 where it is condensed but some amount of E.G vapors
remain uncondensed and it is low velocity vapors therefore a super
sonic velocity vapors of E.G that coming from glycol evaporator take
these slow vapors to the jet through venturi to maintain the pressure.
17
HTM
HTM

18. E.G VAPOUR JET: (17-J01)
17-J01 is a unit with 4 stage of E.G
vapor jet and three condenser. Off gas from 17E01 is sucked by the
first jet where it is condensed by showering of spray E.G with
jacketed heating to prevent the formation of oligomers. It is then fed
into second and at last third jet where the remaining vapors are
condensed. 17T02 is used to collect the condensed E.G from the
three jets. 17TO3 is used to collect all spent E.G including E.G
condensate by 13C01, 14E01 and 15E01. The remaining
uncondensed is then sucked by the vacuum where it is further
condensed and remaining E.G is then vent to the atmosphere but it is
less in amount.
FILTER: (18-F01)
The material from 17R01 is enter into 18F01 where the
further impurities is taken out. 18F01 is the filter with the size of 40
micron and having 74 candles. The material from 17R01 is highly
viscous and due to its smaller micron size as compared to 16F01,
18F01 filter is blocked easily and then sent to the filter cleaning area.
CUTTER:
The material from 18F01 is then divided into 2 sections.
One goes to three cutters and other goes to another three cutters by
passing through dia head having 78 laces, 39 in front and 39 at the
back. Dihead has 19 sensors that alarm at any dangerous and
unhealthy conditions, in this situation cutter goes at the waste. It uses
three types of water:
1) CONVEYING WATER:
It is used in the cutter to prevent from high temperature.
2) OVER FLOW WATER:
It is used to convey the laces or spaghetti.
3) SPRAY WATER:
It is used to maintain the temperature during conveying.
18

19. The cutter consists of 2 parts to ensure efficient cutting:
1) UPPER FEED ROLLER
2) LOWER FEED ROLLER
DRYER:
After cutting, the chips are fed into the dryer where the water
content is removed from them by an air sucked with the help of
blower.
VIBRO:
Over size and under size chips is separated in this section and
then sent to the SSP plant by the help of conveying air.
EVAPORATOR:
The evaporators (12V01, 14V01, 15V01 and 17V01) are
used to heat up the condensate of HTM vapors by using HTM
liquid. HTM vapors are responsible for jacketed heating.
FILTER CLEANING AREA
The two filters “16F01” and “18F01” after being used in the process are
going to filter cleaning area and pass through some steps to clean the filter.
1. Hydrolysis
2. first wash
3. okaite
4. second wash
5. demin
6. ultrasonic treatment
19

20. HYDROLYSIS: (28T01)
The first step is the hydrolysis. it is done in a large tank vessel has
temperature of 330 C . In this step, steam is used to melt up the thick
layer of polymer that stick with filter for 18 to 20 hours and thus all
polymer particles drain out and then we send it to different toys and
plastics companies and industries.
FIRST WASH: (28MO4)
After hydrolysis, we wash the filter by using a high pressure gun called
“curchur”.
OKAITE:(28T03)
The third step is the treatment of filter with okaite solution. In this
solution, the concentration of NaOH is 12 %.the purpose of NaOH is
that it is so impressive in shining as well as to prevent the corrosion. it is
also done in a tank vessel has a temperature of 115 C for eight hours.
okaite is basically a Singaporean product.
SECOND WASH : (28M04)
Again, we wash the filter by the same high pressure gun.
DEMIN: (28T04)
After being washed the filter, filter is treated with dimineralize water
(demin).the large tank vessel serves for this purpose at 100 C for eight
hours. In this vessel coiling is used to heat up the water present in the
vessel and through this coil, steam is passed so at 100 C, water boils
therefore heating is done there by water.
ULTRASONIC TREATMENT:(28M06)
The last step of filter cleaning is the treatment of filter with ultrasonic or
laser rays. the duration of this is four hours and we can run 07 candles at
a time.after completing the treatment, a black particles present at the
bottom of water in which candles is treated.
20

21. FURNACE
The two heating material used in the whole process is the sandotherm (di
phenyl ether) and dowtherm (di phenyl oxide) .they both come from the
furnace with sufficient amount of heat.
Three things are necessary for fire or burning.
Fuel
Air
Heat
BLOWER
The blower sucks the atmospheric air and sent it to the economizer.
ECONOMIZER
In economizer, heat exchange is done the hot air from furnace heat up the air which is
coming from blower and then vent to the atmosphere through stack and upcoming hot
air is entered into furnace.
ELECTRICAL IGNITER
Electrical igniter is made up of silicon carbide or nitride and as electricity passes
through the igniter, it will become red hot and ignite the pilot gas.
FLAME SENSOR
The purpose of this is to sense the flame either it is on or off, the fuel gas
is entered into the furnace so if flame is not properly switched on then
pressure will increase and cause a damage that’s why we have to sense
the flame.
21

22. Why do we use fuel gas instead of furnace oil?
We use fuel gas in the furnace because it is cheaper than oil and we have
to maintained the pressure of gas up to 600 mbar but if the gas is not
coming at that pressure, we use furnace oil that’s why we have given a
line of furnace oil normally we don’t use it so we have to circulate it
continuously through pumps and give some amount of heat through
steam because it is highly viscous and vegetate in the lines.
ATOMIZATION
When we use the furnace oil, we entered it in the furnace with some
amount of steam so as to atomized it (break it into small particles like
atom) as it is so good for efficient burning. for this purpose we installed
here a steam generator.
INSULATION
The insulation is made up of glass wool having glass particles. foam can
be used but normally it is used for chillers.
PDRC
It is used to maintain the pressure of gas.
PROCESS
There are three furnaces installed in series in which two furnaces serve at
a time and one is on stand by.
There are six coils inside the furnace in which HTM is present to get
heat. The temperatures of these six coils are approximately to 325C,
325C, 326C, 326C, 327C, and 327C.
The hot air coming from the economizer at a flow rate of 800-1200 m/h
entered into the furnace and contacts it with fuel gas and then electrically
heating, a flame created up to the height of 6 ft, and there are two flames
inside the furnace.
22

23. The supply of HTM is at 327C and a flow rate of 480-515 m/h and the
temperature difference between return and supply is approx 32C.
Nitrogen gas is used when we need to prevent from any harm or burning
or fire or a side reaction during any job or activity.
Aldehyde can be used for fire in furnaces but we do not use it because it
the lines as it is acidic that is why we vent it into the atmosphere at
standard height.
SSP (SOLID STATE POLYMERISATION):
The amorphous chips coming from poly 2 is then feed into the three
storage silos having capacity of 300m,300m,80m and then it is conveyed
by air to the surge silo from the two silos 2PK2A and 2PK2B ,one is
running at a time and one is on stand by.
SURGE SILO (4BE-100)
Automatic control system switch the feeding of chips , high level
condition switches off and low level condition switches on. The chips
level indicator indicates the level of the chips. in surge silo, there is a
gravimetric feeder which is continuously purged by the stream of
nitrogen ,the pressure of nitrogen gas is slightly lighter from the loop
pressure to allow the chips to flow.
The surge silo is sized and shaped in such a way that the PET solids
remains inside the silo while the transport air will be vented to the
atmosphere outside the plant.
SHANK UNIT
Electric motor moves the paddle. The system measuring the torque of
wheel versus chips, measure the throughput (coriolis principle) ,then
compare it by set value and then adjust the speed of upper rotary valve.
ROTARY VALVE
23

24. The rotary valve with variable speed controlled by the inverter used for
feeding and the other rotary valve 4G-100 with fixed rotary valve for
nitrogen isolation purpose.
PRE-CRYSTALLIZER
It is continuously fed through the rotary valve. in pre-crystallizer the
following operations are performed.
Heating the chips
Pre crystallization of chips of PET to about 35 % by weight with agitation to
prevent sticking I glass transition phase.
Dedusting of polymer
In pre crystallization there are two chambers, the temperature of first is 156
C and temperature of second is 150 C .the pressure of first is 155 mbar and
the other is at 125 mbar. In pre-crystallizer the hot nitrogen gas first
fluidized the chips and then heat up to about 200 C in order to obtain certain
degree of crystallization. The fluidized nitrogen is processed to twin
cyclone.
NITROGEN LOOP
TWIN CYCLONE (4F-100 A/B)
The fluidized nitrogen is hen processed to twin cyclone .the major amount of
dust is removed through the twin cyclone and some amount of chips that
come here with nitrogen gas and then it collected in the dust collection.
NITROGEN FILTER (4F-101)
The nitrogen gas is then processed in the nitrogen filter in order to remove
the further amount of dust if present.
HEATER (4E-100)
It is basically an oil to gas heat exchanger. After passing the nitrogen filter
the gas is blower to the heater. After the heater, nitrogen gas is again
recycling to the pre-crystallizer. The purpose of nitrogen gas used in pre-
24

25. crystallizer is to fluidize the chips and to prevent it from sticking at glass
transition state.
CRYSTALLIZATION
The PET is then fed to crystallizer 1 (4E-300) and then crystallizer 2 (4E-
301) .the crystallization process is completed in the crystallizer and chips
temperature is increased up to the required conditions. the machines are kept
at crystallization temperature by recirculation of HTM in the paddle type
screw conveyors, two paddles running at about 10 rpm, as well as in the
jacket. wet nitrogen removes the fines as well as acetaldehyde released
during heating by counter current .the nitrogen is then fed to cyclone 4F-401
for dust separation .the degree of crystallization at the outlet is about 45% by
weight.
The chips coming in the crystals having an amount of following groups.
Carboxylic end groups
Vinyl ester end groups
Hydroxyl end groups
Wet nitrogen having amount of water react with these groups to form
acetaldehyde.
SSP REACTOR
The hot chips from the second crystallizer 4E-301 are fed through the rotary
valve 4G-401 to the reactor. The reactor is jacketed vessel where circulation
of HTM is provided to maintain the temperature. The HTM is pumped by
4G-705 a/b to the reactor. The hot nitrogen is flowed counter currently to
collect the side products and its temperature is controlled by the heater 4E-
402.the reactor is equipped with nine temperature indicators. Nitrogen
coming from reactor is mixed with nitrogen from second crystallizer is then
processed to cyclone 4F-401 and then sent to pre-crystallization loop.
COOLING
The incoming chips are at about 210C but at the outlet of fluidized bed (4E-
500) its temperature is reduced to 173 C.
FLUIDIZED BED COOLER
25

26. In the cooler deduster 4E-500 the fluidization of the bed, the heat exchange
and the dedusting operations are performed.
The first phenomenon is directly related to the nitrogen velocity through the
bed.
The second one is related to the mass flow rate of nitrogen and relevant
temperature and pressure. The second one is related again to the mass flow
rate of nitrogen but also not the bed depth.
STATIC COOLER
The second cooling step is take place in the static cooler 4E-501 .it is a shell
and tube heat exchanger tubes side chips and nitrogen, shell side cooling
water. In this device the PET chips are cooled down to 50 C before being
discharged through the rotary valve 4G-502.
The heat exchanging efficiency is strictly related to the chips residence time
inside the 4E-501 just in order to keep the right residence time the LIC-510
controls the level of chips, acting to the inverter controlled rotary valve 4G-
502.
NITROGEN PURIFICATION SECTION
The stream resulting from the mixing of following users is exhaust nitrogen
and is feed through the blowers 4G403/4 to the purification section.
PRECRYSTALLIZER
CRYSTALLIZER 1
CRYSTALLIZER 2
FLUIDIZED BED COOLER
REACTOR
The inert gas coming from these users having an amount of water,
acetaldehyde, ethylene glycol and vinyl end groups. The dirty nitrogen will
fed to purification plant by 4G-403 and 4G-404 blowers.
It is divided into two sections.
26

27. OXIDATION UNIT
The impurities are then oxidized in a catalytic bed reactor (4R-200) using
instrument air in the presence of Pt/Pd catalytic bed and the product is CO2
and water.
NITROGEN FILTERS (4F200 A/B)
It is then fed into the filters to remove solid particles.
GAS TO GAS ECONOMIZER (4E-200)
The nitrogen gas at about 208 C is then fed to economizer for the partial
recovery of reaction temperature heat. The nitrogen gas at its outlet is about
288 C.
MIXING WITH AIR
The nitrogen gas is then mixed with a control flow of air in order to supply
the right quantity of combustion oxygen necessary to perform the
combustion catalytic reaction.
ELECTRICAL HEATER (4E-201)
It is used to lift the nitrogen gas temperature to the required reaction
temperature of about 320 C.
At the outlet of the reactor, amount of residual oxygen is measured by
analyzer and then through the controller, amount of reaction air will control.
After reactor nitrogen gas is fed to the 4E-200 economizer for the reaction
heat recovery.
Then this gas is free of hydrocarbon, just a few ppm with some moisture, in
order to verify the contents the hydrocarbon there is a flame ionization
detector is installed then this gas is sent to drying unit.
DRYING SECTION
HEAT EXCHANGER (4E-202)
The nitrogen gas that comes from 4E-200 heat recovery economizer at a
temperature of 250 C. will flow through the heat exchanger where it is
cooled down with cooling water to about 35 C.
27

28. DRYERS (4D-200)
The gas is fed through the number of automatic selection valves to the one
of the two dryers that is active.
In a dryer, a moisture adsorbent molecular sieve made up of aluminum
silicate that remove all the moisture present in the inert gas.
DRYER REGENERATION SYSTEM
As was explained in the previous section that after some time, the dryer is
saturated with water.
The dryer generation system is made up of following two steps.
The heating of dryer saturated bed in order to remove the moisture.
The cooling down of dryer regenerated bed.
The heating of dryer saturated bed is the first phase and takes about 8 hours
during which all moisture in the dryer will be removed.
The gas regeneration loop uses nitrogen as a regenerative gas at temperature
of about 250 C.
In period of 4 hours the dryer will cool down to the temperature of about
40C.at this stage dryer is regenerated and ready for the exchange with the
saturated one.
HTM CIRCUIT:
The HTM uses are:
PRECRYSTALLIZER NITROGEN REACTOR
CRYSTALLIZER 1
CRYSTALLIZER 2
REACTOR
The oil circuit is connected to the HTM expansion vessel purged with
nitrogen.
The HTM oil that is delivered from HTM circuit to crystallizer 1 and 2 is
divided into three streams.
The crystallizer jacket
Crystallizer first shaft
Crystallizer second shaft
The three streams are then collected to the outlet of crystallizer. the oil
return header is connected to suction side of HTM pumps and also
connected to HTM expansion vessel.
28

29. "UTILITIES"
USERS:
1) POLY I
2) POLY II
3) S.S.P I
4) S.S.P II
5) MOULDING
MAIN PLANTS:
1) NITROGEN GENERATION PLANT
2) DEMIN WATER PLANT
3) COMPRESSOR
4) CHILLER
5) FRESH WATER/RAW WATER/MOBILE WATER
6) DRYERS
1) NITROGEN GENERATION PLANT:
NITROGEN GENERATORS
29

30. PSA VSA MEMBRANE PLANT
PURE N2 TECHNICAL N2
(100%free of O2) (99.5% to 99.99% free of O2)
PRESSURE SWING ADSORPTION:
a) Air Filtration
b) Air Supply (Pressurization)
c) Adsorption
d) Re-Generation
f) Exhaust/swing
AIR SUPPLY
Air is pressurized at 9 bars into the first adsorber and the other is at
stand by. In adsorber carbon molecular sieves is used having a small
opening. Oxygen molecule is smaller than nitrogen molecule that's
why these sieves adsorb oxygen and nitrogen passed through it.
After some time, CMS is saturated with oxygen and needs
to be re-generated. During re-generation air is pressurized into the
30
ADSORBER 1 ADSORBER
2
MUFFL
ER

31. other adsorber. In re-generation, valve is opened and all the oxygen
is moved from 9 bars to 1 bar and creates a noise that's why muffler
(silencer) is installed to minimize the sound. In this way all the oxygen
is exhaust (swing) into the atmosphere.
2) DEMIN WATER:
a) Filtration
b) Cation Exchange
c) Anion Exchange
d) Re-Generation
a) FILTRATION:
The raw water or a fresh water is first filtered by passing through two
filters "SAND FILTER" where dust or a gravel particles is separated
out and then this water is passed through "CARBON FILTER" in
which activated carbon is used to dechloronize the water.
b) CATION EXCHANGE:
The Cations of water like Ca,Mg is separated by passing it through
cation exchanger in which cation resins is used to take out these
cations to form cation free water. We use two cation exchanger; one
is at service and other is at stand by.
c) ANION EXCHANGE:
The water is then passed through anion exchanger in which anion of
wter like CO3,HCO3 is adsorbed by anion resins. The two anion
exchanger is used; one is at service and other is at stand by. Now the
water is free of ions and recall it "DEMIN WATER" or "DEIONIZE
WATER".
d) RE-GENERATION:
After some time, the two exchangers are saturated with the ions. So
they need to re-generate for re-use.
i) CATION EXCHANGER RE-GENERATION:
31

32. The Cation exchanger is treated with hydrochloric acid(HCl) to re-
generate, the H-positive ions of HCl replace the ions of Mg and Ca
adsorb by the exchanger and Mg,Ca react with the ions of Cl to
become MgCl2 and CaCl2 and then passed out. This H-positive ions
add up in the water when we will reuse it.
ii) ANION EXCHANGER RE-GENERATION:
The Anion Exchanger is treated with NaOH to re-generate, the OH-
negative ions of NaOH replace the ions of CO3 and HCO3 and then
they react with Na to form Na2CO3 and NaHCO3. These OH-
negative ions add up to water when we will reuse it.
ANION EXCHANGER
RAW WATER
CATION
EXCHANGER
DEMIN WATER
3) COMPRESSOR:
AIR COMPRESSORS
5 HIGH PRESSURE 3 LOW PRESSURE
32
CARBON
FILTER
SAND
FILTER

33. (8-10 bar) (3-3.5 bar)
Instrument air conveying air
Types:
Dynamic (rotary)
Displacement
a) screw
b) b)scroll
c) reciprocating
COMPRESSOR:
a) Air Filter
b) Low pressure Element
c) Inter cooler
d) High pressure Element
f) After cooler
a) AIR FILTER:
The air is entered at 1 bar pressure into the filter where the
dust particles are separated.
b) LOW PRESSURE ELEMENT:
After the filtration, the air is compressed in the low pressure element
by passing it b/w the two different size screws, the pressure at the
outlet of LP element is 3.0 - 3.5 bar. Cooling water is circulating in the
LP element to maintain the temperature. Small size screw rotates
faster than large size screw. The different rotations of the screw done
by the help of a shaft in gear box driven by a motor.
c) INTER COOLER:
After the L.P element the air is cooled by circulating cooling
water in a coil. After the L.P element, the temperature of air is high
because of increase in pressure.
33

34. d) HIGH PRESSURE ELEMENT:
After the inter cooler, the air is passed through high pressure
element, This is same as L.P element and they both are of a type of
screw compressor. At the outlet, the pressure is about 7.5 - 10 bar.
f) AFTER COOLER:
Now this pressurized air is at last passed through another
cooler where it is further cooled by cooling water. The compressor
with two elements and two coolers are "DOUBLE STAGE
COMPRESSOR" and the compressor with single element and a
cooler are "SINGLE STAGE COMPRESSOR". After cooler the air is
dried to remove moisture and then this air is distributed where it is
use.
4) CHILLER:
1) VAPOUR COMPRESSION
2) VAPOUR ABSORPTION
1) VAPOUR COMPRESSION:
34

35. First the refrigerant gases R-22, R-134A and R-404 is compressed to
attain the pressure, then this gas enters into the condensor where it is
converted into small droplets of liquid by using cooling water. The
boiling point of refrigerant gases is about -40 degree centigrade. So
below -40 degree centigrade it is in liquid form and after condensor
the small droplets of liquid are gathered in a expansion valve. After
passing the expansion valve the refrigerant liquid is entered into the
evaporator where it cools the chilled water and discharge it at 7
degree centigrade return to the process. In this way the refrigerant
gases vapourize and enters into the compressor and the cycle goes
on. The temperature of cooling water is equal to the wet bulb
temperature and inlet of chilled water is at 12 degree centigrade.
CHILLED WATER IN
C.W IN
CHILLED WATER OUT
C.W OUT
2) VAPOUR ABSORPTION:
The solution of lithium bromide(LiBr) and water is entered into the
generator where the water is vaporized at 100 degree centigrade by
flue gas entering at 380 degree centigrade. Lithium bromide is
separated out from water and enters into the absorber while water
vapors fed into the condenser where it is condensed by cooling coil.
Vapor absorption cycle is basically under the vacuum and that's why
water is condensed at very low temperature, then this condensed
water is entered into the evaporator where it cools the chilled water
and discharges it at 7 degree centigrade. In this way water is
vaporized and absorbed by LiBr in an absorber and again enters into
the generator and cycle goes on. The boiling point of LiBr is about
690 degree centigrade.
35
EXPANSION VALVE
VAPORSCOMPRES
SOR

36. FLUE GAS
H2O VAPORS CW OUT
CW IN
LiBr & H2O
H2O LIQUID
H2O VAPORS
CHILLED CHILLED
WATER IN WATER OUT
5) DRYER:
1) DESICANT DRYER
2) INSTRUMENT AIR DRYER
3) REFRIGERANT DRYER
DESICANT DRYERS:
The compressed air is entered into the desiccant dryer. A long shaft
rotating in the dryer driven by a motor. Silica Jel is in contact with the
rotating shaft that adsorbs the moisture from the air. Instrument air
dryer is none but the two desiccant dryers connected in series.
MOISTURE FREE AIR
36
GENERATOR CONDENSOR
EVAPORATORABSORBER

37. COMPRESSED
AIR
QUALITY LAB
1) DETERMINATION OF ALDEHYDES IN LIQUID SAMPLES:
PRINCIPLE:
The carbonyl group(=C=O) of many aliphatic and aromatic
aldehydes and that of aliphatic and hydro aromatic ketones with
sodium bisulphite by forming addition compounds so called alpha-
oxysulphonic acid.
After this reaction, the excess sodium hydrogen bisulphite
is first oxidized by titration with iodine solution to form sulphate, then
sulphite link to carbonyl group is visually titrated with 0.1N iodine
standard solution unsing starch solution as the indicator. Upon
oxidation some addition compounds is formed which is then
decomposed by adding sodium hydrogen carbonate.
ACCURACY:
+ 5 % relative/ - 5 % relative
TIME REQUIRED:
About 2 hrs
2) DETERMINATION OF THE IV OF PET:
PRINCIPLE:
i) The polymer is dissolved in the mixture of phenol and 1,2 dichloro
37

38. benzene or 1,1,2,2-tetrachloroethane where upon the time of flow is
determined in an ubbelohde viscosimeter.
ii) The relative viscosity is obtained from the quotient of time of flow of
polymer solution to that of pure solvent.
iii) The relative viscosity is linked with intrinsic viscosity by
"BILLMEYER'S EQUATION"
iv) The intrinsic viscosity is defined as the limiting value of the ratio of
natural logarithm of relative solution viscosity to the concentration of
polymer in the solution.
ACCURACY:
+1 % relative/ -1 % relative
TIME REQUIRED: 45 min
REQUIRED AMOUNT:
Amorphous: 0.580 - 0.620
S.S.P : A-74 => 0.720 - 0.760
A-80 => 0.780 - 0.820
A-84 => 0.820 - 0.860
3) DETERMINATION OF CARBONYL END GROUPS IN PET:
PRINCIPLE:
The PET sample is dissolved at boiling temperature and the
reflux in the mixture of O-Cresol and chloroform. After cooling to room
temperature, the carbonyl end groups are determined photo
metrically using bromophenol blue as an indicator.
REACTION:
R-COOH + KOH ---------------> R-COOK + H20
TIME REQUIRED:
45 min
38

39. ACCURACY:
+1 mmole/kg / -1 mmole/kg
REQUIRED AMOUNT:
35 - 50 mmole/kg
4) DETERMINATION OF M.P OF POLYESTER:
PRINCIPLE:
The polymer specimen is observed b/w crossed polarizers
while heated at a constant heating rate. The differentiate scaling
curve is plotted ranging from 30 - 300 degree centigrade.
By this method, we can also determine the glass transition
state and out of melt(cool).
TIME REQUIRED:
1 hr after the temperature calibration has been calibrated.
ACCURACY:
+ 1 degree centigrade absolute/ -1 degree centigrade
absolute
REQUIRED AMOUNT:
BGC: 245 - 250 degree centigrade
FGC: 250 - 255 degree centigrade
5) DETERMINATION OF THE COLOUR NUMBER OF PET:
PRINCIPLE:
i) The tristimulun color difference meter determine the color of the
sample in three photocells which are considered by red, green, blue
filter respectively.
ii) The crystallized and grinded sample contain in a measuring cup is
exposed to standard illumination C (daylight)/standard observer 2
degrees at an angle of 45 degree.
iii) The reflected beams are measured at an angle of 0 degree.
iv) The color is measured as X.Y and Z values, from these values
39

40. yellowish ness index (YI) or the color number l, a, b (hunter) can be
calculated.
ACCURACY:
+0.3 units/ -0.3 units.
TIME REQUIRED:
Approx 2 hrs
6) DETERMINATION OF ACETALDEHYDE IN PET:
PRINCIPLE:
i) First the PET is cooled in liquid nitrogen at -197 degree centigrade
then it is grinded to 500 micron particle size. The purpose of cooling
is to prevent it from being vaporized as it is so volatile during grinding.
ii) It is then sealed in a small tube and gives the temperature of 150
degree centigrade in head space and it becomes in gaseous form.
iii) Then injector injects the gas and fed into the gas chromatographer
and then we can determine the contents of acetaldehyde.
TIME REQUIRED:
About 90 min
REQUIRED AMOUNT:
Less than 1 ppm(0.73 is standard)
7) DETERMINATION OF MOISTURE CONTENTS IN PET:
PRINCIPLE:
I) The PET specimen is contained in a pointer in the heater at 205
degree centigrade and nitrogen is then passed through the specimen
and sucks the moisture from it.
ii) Then this moisture containing nitrogen gas is fed into
detector(MECCO moisture analyzer) that detects moisture contents.
REQUIRED AMOUNT:
S.S.P: Less than 100 ppm
40

41. Amorphous: 600 - 700 ppm
TIME REQUIRED:
About 70 min
8) DETERMINATION OF YELLOW CHIPS IN PET:
PRINCIPLE:
A back of chips is holed on the screen and the ultravoilet
rays is passed through it by which we can determine yellow chips
easily.
9) DETERMINATION OF ASH CONTENT IN POLYESTER:
PRINCIPLE:
A sample is taken in porcelain crucibles and then gradually
increase the heating lod up to the heating stage 6 until all the
carbonacues matter is ashed. Transfer the crucibles to the muffle
furnace and ignite at 700 degree centigrade for 30 min. Transfer the
crucibles from the furnace to the desiccators and allow cooling and
determining the weight.
ACCURACY:
+2 % / -2 %
TIME REQUIRED:
About 6 -7 hrs
TEST FOR POLY II:
1) PTA/IPA :( ONCE PER DAY)
a) WATER CONTENT: Less than 0.2 % wt
b) PARTICLE SIZE : < 40 micrometer(0 - 20 % wt)
150 - 250 micrometer(0 - 15 % wt)
> 250 micrometer(0 - 3 % wt)
c) ACID NUMBER : 671 - 677 mg KOH per gram
41

42. d) COLOUR NUMBER : b => 0 - 2.5
2) PASTE:(ONCE PER DAY)
a) PTA CONTENT : 69 - 71 %
b) DENSITY : 1.331 - 1.431g/cm3
c) MOLE RATIO : 1.08 - 1.18
3) EST 1:(ONCE PER DAY)
a) ACID NUMBER : 47 - 53 mg KOH per gm(every 8 hours)
b) COLOUR NUMBER : L => 94 - 98
a => -1 to 1
b => 0 - 1.5
YI => -0.2 to 2
c) SAP NUMBER : 550 - 570 mg KOH per gm
d) IV : 0.08 - 0.1 dl/gm
e) DEG : 1.05 - 1.3 %
f) IPA : 1.85 - 2.2 %
g) A.A : 40 - 85 ppm
4) PP II:
a) IV : 0.24 - 0.3 dl/gm
b) CEG : 85 - 110 mole/kg
c) COLOUR NUMBER : L => 42 - 96
a => -1 to -0.25
b => -0.75 to +0.75
YI => -2 to +2
d) DEG : 1.1 - 1.5 %
e) IPA : 1.85 - 2.15 %
f) A.A : 4.5 - 10.5 ppm
5) CATALYST:
a) Sb CONTENT PER BATCH: 6500 - 8000 ppm
6) R.T:
a) Sb CONTENT PER BATCH: 6500 - 8000 ppm
42

43. 7) H3PO4:
a) H3PO4 CONC. : 0.85 %
8) B.T:
a) B.T CONC. : 0.0084 %
9) COLUMN:
a) ALDEHYDE: 0 - 500 ppm
b) E.G : 95 - 100 %
c) H2O : 1 - 3 %
S.S.P:-
1) PRE CRYSTALLIZER:(ONCE PER WEEK)
a) IV :
b) CARBONYL END GROUP :
c) MOISTURE :
d) COLOUR NUMBER :
e) CHIPS SIZE :
f) DEG :
g) IPA :
h) A.A :
i) Sb CONTENT :
j) M.P : (once per month)
The readings of above are same as amorphous.
2) FIRST CRYSTALLIZER:(ONCE PER WEEK)
a) IV :
43

44. b) CARBONYL END GROUP :
c) MOISTURE :
d) COLOUR NUMBER :
e) CHIPS SIZE :
f) DEG :
g) IPA :
h) A.A :
i) Sb CONTENT :
j) M.P :
(Once per month)
The readings of above are same as amorphous.
3) SECOND CRYSTALLIZER :( ONCE PER WEEK)
a) IV :
b) CARBONYL END GROUP:
c) MOISTURE :
d) COLOUR NUMBER :
e) CHIPS SIZE :
f) DEG :
g) IPA :
h) A.A :
i) Sb CONTENT :
j) M.P :
(Once per month)
The readings of above are same as amorphous.
44