resin production
TRANSCRIPT
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Under the guidance of:-
Er. Abhishek Sharma
Presented by:-
Jayant Kushwaha
Pawan kr. Ful faki r
Final year, chemical Engg.
Dr. B. R. Ambedkar ni t , Jalandhar (Punjab)
Understanding & Study of the Resin
Production Process
Vocational Industrial Training Project Presentation
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ABOUT SRF
SRF is a multi business entity engaged in the manufacture of
Chemical based industrial intermediates. Today its business
portfolio covers Technical Textiles, Chemicals, Packaging
films and Engineering Plastics. SRF Limited is a USD 760MIndustrial group. From its inception in 1974, SRF today
operates from eight plant locations in India and abroad.
Packaging Film Business (PFB) involves the production of
Bi-axially Oriented Poly Ethylene Terephthalat (BOPET) orPolyester Film.
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INTRODUCTION TO RESIN PLANT
In Resin Plant, PET Resins (Chips of PET Polymer) are made from
which the packaging films are made.
In Resin Plant, Batch Polymerization (BP) & Continuous
Polymerization (CP) both are running simultaneously.
At full capacity CP runs at 150 tons/day and BP runs at 20
tons/day.
Polyester or Poly Ethylene Terephthalat (short PES or PET), is
produced in two chemical steps.
The raw material, 1 mol of Pure Terephthalic Acid (PTA) reacts
with 2 mol of Mono Ethylene Glycol (MEG or simply EG) at
raised temperature (240C 260C) to form Bis (2-Hydroxyethyl)
Terephthalat (BHET) also named Di-glycol Terephthalat (DGT).
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INTRODUCTION (cont inued)
This first step of reaction is called esterification and can be
carried out at different pressures.
In this plant MEG or EG (monomer) is fed at lower
molecular ratio than 2. Due to which the product obtained,the monomer is a mixture of monomer, pre-polymer & non-
reacted PTA and EG.
In the second step the monomer is poly-condensed by the
use of a catalyst (Sb2O3) & heat stabilizer at Vacuum and
temperature between 270C - 285C.
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RAW MATERIAL FOR RESIN PLANT
Pure Terephthalic Acid (PTA)
PTA is a white crystalline free
flowing powder.
It is delivered in tank trucks,container or 1 ton flexible big bags
which are kept at discharge station.
These big bags are lifted to the top
of the PTA feeding tank by an
elevator.
These bags are then emptied
directly into the PTA feeding tank.
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RAW MATERIAL FOR RESIN PLANT
Mono-Ethylene Glycol (MEG
or EG)
MEG is a clear liquid, mixable with
water. It is delivered in tank trucks or
railway tank wagons.
After laboratory check, the MEG is
pumped into the storage tank. From there the MEG is
automatically pumped to the
consumers in the poly-building.
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OTHER CHEMICALS USED IN RESIN PLANT
Di-Ethylene Glycol (DEG)
Catalyst:- Antimony Tri-Oxide (Sb2O3)
Poly-Phosphoric Acid
Colour Additive RED (RG)Colour Additive BLUE (RH)
Silica
Magnesium AcetateHeat Transfer Fluids (HTF):-
Therminol 66
Therminol VP-1
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Chemistry of Polyesters (PET)
Polyesters are highly polymeric substances, the individualunits of macromolecules are connected by the ester groups.
O
| |CO
Esterification Reaction:
n HOOC COOH +(n+1) HOCH2CH2OH
n HOCH2CH2OOC OOC-CH2CH2OH +2n H2O
Condensation Reaction:
HOCH2CH2OOC -[-COOCH2CH2OOC -]-(n)COOCH2OH +
HOCH2CH2OOC OOC-CH2OH HOCH2CH2OH +
HOCH2CH2OOC -[-COOCH2CH2OOC -]-(n+1)COOCH2OH
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PROCESS DESCRIPTION9
Polyester or Poly Ethylene Terephthalat (short PES or PET), is
produced in two chemical steps. The raw material, 1 mol of
Pure Terephthalic Acid (PTA) reacts with 2 mol of Mono
Ethylene Glycol (MEG or simply EG) at raised temperature
(240C - 260C) to form Di-glycol Terephthalat (DGT).
The production plant consists of the following main process
steps:-
1) Paste Making2) Esterification with Pre-polymerization
3) Polycondensation
4) Chips Production
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PASTE MAKING10
o The paste making system for both CP & BP are locatedbelow the PTA feeding tank. This tank has double cone andserves both paste mixing system for CP & BP.
o All raw material PTA, MEG, DEG are mixed to form a paste
which is feed to the esterification.o The paste is white slurry. Its viscosity is depending on mole
ratio, form and size distribution of PTA crystal.
o Mixing of all raw material including colorful additives is
done in the paste mixer at atmospheric pressure, but withnitrogen purge.
o The mole ratio of EG/PTA, is determined according to thesource and type of PTA and other operating factors.
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CATALYST PREPARATION SYSTEM11
EG moistured Antimony Trioxide is used as poly-
condensation catalyst.
The catalyst is dissolved in virgin Ethylene Glycol at a
temperature of 130 to 140C. The conc. of catalyst in the solution should be 1 to max
1.5%. The catalyst is poured into the dissolving vessel.
The catalyst solution is dosed into the paste mixer
according to the PTA feed. Normal feed is 270ppm Sb onpolymer.
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ESTERIFICATION12
Esterification and pre-polymerization takes place in UPR
(Universal Polymerization Reactor). UPR have 3 zones:
1. The ester 1 zone
2. The ester 2 zone3. The prepoly zone
In the esterification zones the raw materials are reacting
and forming the monomer DGT. The esterificationreaction is carried out in two reaction zones, one at the
top of the other and at a product temperature of approx.
255C to 262C and overpressure.
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ESTERIFICATION (cont inued)13
The first reaction zone is equipped with an inbuilt heatexchanger and an agitator that works as a circulation
pump. That agitator circulates the product through the
heat exchanger coils and mix the new PTA/EG slurry
with the reacted monomer.
The second reaction zone serves for further reaction. In
both zones reaction water and EG are Evaporated.
In the first zone, which is operated at approx 2 to 2.5 barsoverpressure, the large amount of heat, which is
required to heat the raw materials and to evaporate
water and EG is transferred to the product.
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ESTERIFICATION (cont inued)14
The monomer of first esterification zone is feed to the secondzone by pressure difference. The second zone is operated at
a lower pressure, preferably at 0.4 to 0.7 bar overpressure.
The product operating temperature is about 260C to 262C.
The product transfer from 2ndester zone to the Prepoly zone,
which is the lower part of the UPR reactor is achieved by the
difference in operating pressure. The ester 2 operates at 0.4
to 0.7 bar & the Prepoly zone at a vacuum of 25 to 40 mbar.
In this plant a monomer connection from ester 2 to the batch
plant is foreseen. By a mass flow meter and control valve a
certain quantity of monomer can be continuously taken out
and fed to the esterification reactor of the batch plant.
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PROCESS COLUMN & STRIPPING COLUMN
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o The Process vapor of esterification is led to a Process
Column to separate water from EG.
o The column top is operated at atmospheric pressure and has
a re-boiler at its lower end.
o At the top of the column, the low boilers like water &
aldehydes are bleed off. Whereas the high boilers, EG &
some water leave the column at the bottom.
o The condensed reaction water is led to a stripping column inorder to reduce the BOD & COD values. The water is
flowing from top to bottom whereas air is passed in counter
current.
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POLYCONDENSATION16
In Polycondensation, the remaining excess EG is evaporated, whichresults in the formation of long molecular chains of polymer withthe required properties of the Polyester.
The reaction takes place in two steps at raised temperatures, 270Cto 285C and vacuum between 40 and 0.5 mbar.
The first step of Polycondensation is made in the Prepoly reactorthat is installed in the lower part of the UPR reactor. This part ofthe reactor is a combination of flasher and pre-polymerizer inwhich up to 95% of the excess EG is evaporated.
From the outlet of Prepoly the polymer flows to a polymer gear
pump that transports the pre-polymer to the Finisher. Aviscometer is installed in the polymer line that measurescontinuously the viscosity of the polymer that is fed to theFinisher. In the Finisher the pre-polymer is brought to its finalviscosity and properties.
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FINISHER17
o The FINISHER is a horizontal jacketed heated vessel with a
horizontal, ex-centric shaft less cage agitator with disks.
o The speed of the shaft can be varied between from 0.5 to 5
rpm. A standard speed is 2 to 3 rpm.
o In the product inlet zone, where the viscosity is relatively
low, the pre-polymer is moved upwards by cups mounted to
the disk rings.
o While rotating to the top, the cups are emptied and thepolymer flows down, forming films & strings.
o The internals of the reactor are designed to work as a
cascade to avoid remixing of the polymer.
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CHIPS PRODUCTION18
Behind the polymer filter, the polymer flows to the two die(casting) heads of the underwater (Reiter Supply).
The polymer is pressed through the holes of the die plate,
forming wires of approx. 2mm to 3mm diameter. Below
the spinnerets the polymer wires are cooled down on the
special stainless steel cooling board, they solidify and are
led to the cutter.
In the cutter the wires are cut to length. Solidification andcutting is done under water to cool the polymer and to
avoid sticking.
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CHIPS PRODUCTION (continued)19
The mixture of cooling water and chips, coming from thecutter is pre-separated in special screen. A part of the
water flows back to the water tank of the cutting system.
The chips and remaining water is passing a pre-dryer,
centrifuge in the centrifuge the remaining water is
separated from the chips and also flows to the water tank.
The chips are falling on a screen that separates uncut or
long parts.
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STABILIZER PREPARATION SYSTEM20
Poly Phosphoric acid is used as heat stabilizer.
The stabilizer is a viscous liquid that is dissolved in virgin
EG at a temperature of 30 to 40C.
The conc. of stabilizer in the solution should be 1 to 1.5%.Normally the concentration of active stabilizer in the paste
is around 82 to 84%.
The stabilizer solution is dosed into the monomer after
esterification.
Normal feed is 10 to 15ppm phosphorous on polymer.
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SILICA PREPARATION SYSTEM21
Silica slurry is prepared using silica and virgin glycol.
The final conc. (ppm) of silica slurry to be prepared is first
decided, then measured quantity of virgin EG is taken in
preparation vessel.
Measured quantity of silica powder is then added to
preparation vessel over a period of 2-3 hrs.
The slurry is then passed through a pearl mill which crushes
the agglomerates. Then this slurry is transferred to an adjustment vessel where
the conc. is measured & glycol is added to adjust the
concentration.
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