Internship Report of Nimir Chemicals
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NIMIR VISION STATEMENT
NIMIR Chemicals Pakistan Limited will fulfill the stakeholder
expectations of our "Customers," "Shareholders," "Employees,"
"Business Partners," "Local Communities and the
Environment.".
NIMIR MISSION STATEMENT
Create Social Value while fulfilling the stakeholder
expectations.
Statement of Ethics
We believe in a stimulating and challenging team oriented work
environment that encourages, develops and rewards
excellence. We are committed to diligently serving our
community and stakeholders while maintaining high standardsof moral and ethical values.
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Table of contents
1.Health ,safety and environment department
2.Quality control department
3.Ware house
4.Electrical department
5.Mechanical department
6.Instruments department
7.Utility plants
Demine water
Boiler
Turbine
Compressor Nitrogen generation
8.Process and production department
PHTHALIC ANHYDRIDE
MALEIC ANHYDRIDE
DI-OCTYL PHTHALATE
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2. Quality control laboratory
Purpose
This laboratory is used for all the chemical reaction occuring in industry and check all the quality
of the raw material, product and water using in the industry. This lab contain different types of
apparatus for different test such as water analysis, acid value, total fatty acid, free acid,
moisture content etc .the plant contain different intermediate point where the sample is
collected and then it is send to Q.C lab where the chemist check out the complete analysis of
the sample and then make report by performing different test .then the report is send to plantoperator where dosing is done according to the requirement. The apparatus use in the lab is
following.
1. Gas chromatography
2. Hydrogen generator
3. Refractor meter
4. Sensodirect
5. Weighting scale
6. Titration
7. Viscometer
8. Water bath
9. Gas analyzer
10.Magnetic stirrer hot plate
Apparatus and their function
1 .Gas chromatography
It is basically a separation technique .this is used to check out the quality of the product
and raw material .it contain two phases one phase is stationary and and other is mobile phase.
Gas chromatography is a common type ofchromatography used inanalytical
chemistry forseparating and analyzing compounds that can be
vaporized withoutdecomposition.Typical uses of GC include testing the purity of a particular
http://en.wikipedia.org/wiki/Chromatographyhttp://en.wikipedia.org/wiki/Analytical_chemistryhttp://en.wikipedia.org/wiki/Analytical_chemistryhttp://en.wikipedia.org/wiki/Separation_processhttp://en.wikipedia.org/wiki/Vaporizedhttp://en.wikipedia.org/wiki/Chemical_decompositionhttp://en.wikipedia.org/wiki/Chemical_decompositionhttp://en.wikipedia.org/wiki/Vaporizedhttp://en.wikipedia.org/wiki/Separation_processhttp://en.wikipedia.org/wiki/Analytical_chemistryhttp://en.wikipedia.org/wiki/Analytical_chemistryhttp://en.wikipedia.org/wiki/Chromatography -
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substance, or separating the different components of a mixture (the relative amounts of such
components can also be determined). In some situations, GC may help in identifying a
compound. In gas chromatography, the mobile phase (or "moving phase") is a carriergas,
usually aninert gas such ashelium or anun-reactive gas such as nitrogen. The stationary
phase is a microscopic layer ofliquid orpolymer on an inertsolid support, inside a pieceofglass ormetal tubing called a column. The gaseous compounds being analyzed interact with
the walls of the column, which is coated with different stationary phases. This causes each compound
toelute at a different time, known as the retention time of the compound. The comparison of retention
times is what gives GC its analytical usefulness.
2.Hydrogen generator
This apparatus is used for the generation of hydrogen that is used in the lab .
3.Refractro meterThis apparatus is used for the calculation of refractive index of different chemical used in
industry.
4.Viscometer
This is used for the calculation of viscosity of the chemicals.
5.Senso direct
This is used for the calculation of PH value and conductivity of different chemicals
6.Titration
Titration is used for different test which include hardness of water, ca ions, ma ions, total acid
value, free acid etc.
7.Specrophotometer
This apparatus is also used for different types of test. A spectrophotometer is a device or more
specifically a photometer that is used to measure intensity of light as a function of the
wavelength of light. A spectrophotometer is the combination of two devices, a spectrometer
and a photometer. Spectrometer is used for producing light of any selected wavelength or color
while a photometer is used for measuring the intensity of light. When an aqueous sample of
compound is placed in the light path of the spectrophotometer, the sample may absorb all the
http://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Inerthttp://en.wikipedia.org/wiki/Heliumhttp://en.wikipedia.org/wiki/Reactivity_(chemistry)http://en.wikipedia.org/wiki/Liquidhttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Solidhttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Elutionhttp://en.wikipedia.org/wiki/Elutionhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Solidhttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Liquidhttp://en.wikipedia.org/wiki/Reactivity_(chemistry)http://en.wikipedia.org/wiki/Heliumhttp://en.wikipedia.org/wiki/Inerthttp://en.wikipedia.org/wiki/Gas -
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Result:
Its color will be blue.
Procedure
Lets find the A.V of DOP sample.
Take the sample of DOP at any instant like reactor, stripper and Run down. Take methanol
Commercial in flask. Indicator is Bromoethyle Blue two drops. Titrate it against KOH.
Result
If its color would change like Yellow then its mean that it has some Acid value.
If no change in color occurs then its mean that it has no Acid value.
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CHEMICAL REACTION OCCURING IN INDUSTRY
[O]
1. Orhtho-xylene --------------------> phthalic anhydride + maleic anhydride + citraconic
anhydride
V2O5+Sb2O3
+ benzoic acid + phthalide + ortho-tolyaldehyde
DOP preparation
catalyst
phthalic anhydride + 2 alkyl alcohol ------------------> DI-octyl phthalate +water
Test analysis for 2-EH
Sr.no Test limits
1 Acid value (mg of KOH/g) 0.05
2 Moisture content % 0.13 Purity by GC % wt Min 99.7
4 Appearance clear
5 Specific gravity 20 degree C 0.832-0.833
6 Colour Max 5(APHA)
Test for DOP
Sr .no Tests Limits
1 Acid value 0.022 Moisture content 0.05
3 Purity by GC Min 99.7
4 Appearance Clear
5 Colour Max 30
6 Specific gravity 0.986+0.02
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Test for PA
Sr.no Tests Limits
1 Solidification point 130.9 C
2 Colour (APHA) 203 Heat hazard at 250 C(APHA) 40
4 Purity by GC Min 99.85
5 Benzoic acid % 0.05
6 Sheild life /expiry 0.6 month
Test for MA
Sr.no Tests Limits1 Solidification point 52.4 C
2 Maleic acid(%)
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WATER ANALYSIS
Tests Demin water Boiler feed
water
Boiler blow
down
Cooling water
Limits Limits Limits LimitsPH 6---7 9---9.5 10---10.5 6.5---7
Cond US
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3.Ware house
Purpose
Ware house is also known as the back bone of the industry .it contain all the records of the
stock available in industry such as raw material, packing of material, finishing goods
.equipments etc. moreover warehouse are profit-oriented enterprises so their goal is to
provide the highest service standard at the lowest possible cost and by the highest utilization
of their resources .main objective of ware house is to facilitate all department related to
receipt and issue of material at the right time ,in the right quantity and quality. for the issue of
any material the indent is made for it the main purpose of the indent is to describe the whole
process of receiving ,weighting ,unloading ,storage different raw material received in bulk
quantity in order to ensure effectiveness of material and to avoid any kind of losses ,miss-
happening /accidents during unloading. The ware house department does the following works.
1. Daily stock report.
2. drum inspection
3. Daily drum scale
4. reduce daily wagers over time
5. color coding
Indent procedure
Indent is the document prepared to raise the demand of any item and then owned information
to the procurement dept for subsequent purchase of the indent items. The main purpose of
rising a complete information to the procurement dept .which must be sufficient for purchasing
the required item..indent must be prepared in such a manner that procurement dont have to
reach for the indent department for clarification in general to get them clarified regarding what
actually is the item indented .similarly indent also provide a tool to the warehouse .
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4.Electrical Department
Purpose:
This department control all the parameters or instruments electrically. This department usesfour sources of electricity. 1
st is from WAPDA producing about 1200kv at a cost of 10 Rs. per
unit. The 2nd
source is gas turbine which is the cheapest source of electricity producing 1064kv
at a cost of 4 Rs. per unit. The 3rd source is diesel turbine producing about 800 kv at a cost of
26 Rs. per unit. The 4th
source is steam turbine producing 1150kv.
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5.Mechanical department
Purpose
Tool is the basic of mechanical dept. This dept deal with all the mechanical part of the plant and
solved out all the problem happened mechanically .
Mechanical department deals with the
a) Maintenance, replacement and repair of all Mechanical Engineering equipment and systems.
b) Operation and monitoring of the dynamic positioning system.
c) Plan and construct the installation of mechanical systems.
d) Plan and discuss Risk Assessment Procedures
e) Mechanical equipment inspection and repair.
f) Maintain documentation in compliance with regulatory requirements.
g) Conduct tests to ensure compatibility and safety of components.
h) Coordination of maintenance schedule for mechanical systems and components.
1. 1.stationary part
2. 2.rotary part
1. Stationary part
This include all the stationary part .which is as follows
grinder,dry scale,level ,valve,torque spanner,pipe ranch ,fabrication ,insulation gas ket
,flanges,gland packing,distillation column ,reactor ,column pipening etc
Welding
welding is used for joining metal .it is of three types
electric stick
gas tug
pvc rod
Grinder
This is used for grinding different instrument. This is of two types
disc
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cutting
Spanner
Spanner is used for opening and closing of nut, bolts, etc it is of three types
open
ring
combination
Valve
Valve is used to control pressure, level, flow rate, volume it is of several types which is as
follows.
1.Gate valve
General Characteristics
Straight flow
Directionless valve
Minimum pressure drop
Valve's bore
pipe opening
Not recommended for throttling
Occupy less space as compare to Globe
Low cost
Frequent opening/closing not recommended
A metallic gate/disc is used to stop the flow
2,Globe valve
Causing Turbulence & highP
Plug prone to wear/erosion
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Recommended for throttling
Used for unidirectional flow
Valves bore < pipe opening
3,Plug valve
General Characteristics
Used for quick opening and closing
Not recommended for throttling
Used for more than one inlet/outlet lines
Provides straight through flow
Used for low pressure services
Turn plug at 90o for opening/closing
No gland packing used
Tapered plug is used to avoid sticking
4. Butterfly valve
General Characteristics
Reliable & long service life
Lines cannot be cleaned by pig
Suitable for low pressure service, 10-20 bar
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Leakage 0.5% of rated CV.
Easy to operate, both manually & by remote control.
Circular shaped disc used for quick opening/closing
5 Check valve
GENERAL CHARACTERISTICS
LowP
Quick opening
Low maintenance costs
To control the direction of flow
Used for both high/low pressure
Most reliable and long service life
Used for both horizontal & vertical flow
6.Non-return valve
7.Flaper valve
8.Angle valve
Fabrication
It is used for different line arrangement it include elbow and t-shape. Elbow is of different angle.
Gas-kit
It is used to prevent leakage .it is of different types. Such as graphite, asbestos, sparo-gram, rubber etc
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Flanges
It is used for joint for two pipes
Neck weld, orifice is its types.
Heat exchanger
A heat exchanger is a piece of equipment built for efficientheat transfer from one medium to
another. The media may be separated by a solid wall, so that they never mix, or they may be in
direct contact exchangers.
Types
shell and tube
plate
After a period of use the fouling factors arise in the exchangers that is the rusting and a layer of
foreign items get settled at the bottom decreasing the flow rate. The fouling can arise due to
the following factors.
1.Sedimentation
2.Corrosion
3.Algae growing
4.Salt deposit
5.Coking
6.Chemical reaction
The techniques which are used during operation fouling encountered in heat exchangers are as
under:
1. Mechanical cleaning
2. Chemical cleaning
2. Rotary part
This include all the rotary parts
Compressor, pumps, turbine etc
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Compressor
It is used for making air compressed which is used in plant for different purpose
PumpsIt is used for transferring the liquid from low elevation to high elevation.it is of two types. Pumpis a machine that imparts energy to the liquid.Move liquids from lower pressure areas to areas ofhigher pressure.1. Centrifugal 2.positive displacement
Turbine
This is used for generating electricity from steam and gas
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6. Instrument department
Instrument is an caught device which we can use in process, monitor this action .give the result
on Distribution control system.(DCS) . It is used to control the following parameter.
1. Temperature
2. Pressure
3. Flow rate
4. Level
1. Temperature
Temperature is the measure of hotness or coldness of the body .in nimir for temperature calculation
.thermo couple is used.
Thermo couple
A thermocouple consists of two conductors of different materials (usually metal alloys) that
produce avoltage in the vicinity of the point where the two conductors are in contact. The
voltage produced is dependent on, but not necessarily proportional to, the difference of
temperature of the junction to other parts of those conductors. Thermocouples are a widely
used type oftemperature sensor for measurement and controland can also be used to convert
a temperaturegradient into electricity.
The thermo couple used in nimir is k type American standard. Yellow wire is +ve charge is made
of nickel-chromium and red wire ve charge is nickel aluminium.it have two junction hot and
cold .hot sense the heat and convert it into micro voltage and sent to transmitter which gives
result on the DCS.
2. Pressure
Many techniques have been developed for the measurement ofpressure andvacuum.
Instruments used to measure pressure are called pressure gauges or vacuum gauges.
A manometer could also refer to apressuremeasuring instrument,usually limited to measuringpressures near to atmospheric. The term manometer is often used to refer specifically to liquid
column hydrostatic instruments.
A vacuum gauge is used to measure thepressure in avacuumwhich is further divided into
two subcategories, high and low vacuum .The applicable pressure range of many of the
techniques used to measure vacuums have an overlap. Hence, by combining several different
http://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/List_of_temperature_sensorshttp://en.wikipedia.org/wiki/Gradienthttp://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Measuring_instrumenthttp://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Measuring_instrumenthttp://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Gradienthttp://en.wikipedia.org/wiki/List_of_temperature_sensorshttp://en.wikipedia.org/wiki/Voltage -
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types of gauge, it is possible to measure system pressure continuously from 10 mbar down to
1011
mbar.
3. Flow rate
Flow rate is measured by rotameter. A rotameter is a device that measures theflow
rate ofliquid orgas in a closed tube.
It belongs to a class of meters calledvariable area meters,which measure flow rate by allowing
the cross-sectional area the fluid travels through to vary, causing some measurable effect
http://en.wikipedia.org/wiki/Bar_(unit)http://en.wikipedia.org/wiki/Flow_ratehttp://en.wikipedia.org/wiki/Flow_ratehttp://en.wikipedia.org/wiki/Liquidhttp://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Variable_area_meterhttp://en.wikipedia.org/wiki/Variable_area_meterhttp://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Liquidhttp://en.wikipedia.org/wiki/Flow_ratehttp://en.wikipedia.org/wiki/Flow_ratehttp://en.wikipedia.org/wiki/Bar_(unit) -
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7. UTILITY PLANTS
a) Demin water
b) Boiler
c) Turbine
d) Compressor
e) Nitrogen generation
f) Cooling tower
a)DEMIN WATER
Purpose
It is mostly used for steam generation which is used as a heating medium in plant . It is also used as a cooling medium.
As water is an excellent solvent for many chemicals. So another important utility of
water is as a solvent for preparation of various solutions.
Making of demin water
Cation bed
Raw water from the storage tank is first sent into the cation ion vessel from the top resin RH isadded in it.the +ions in raw water release and the following reaction take place .
2HR+cacl2 CaR2 +2hcl
2HR +CaSo4 CaR2 +h2so4
2HR +Ca(HCO3)2 CaR2 +2H2Co3
De gaser vessel
This vessel is used to remove the dissolve oxygen from water .force draft fan is placed at the
bottom.
Anion bed
In this bes vessel the raw water donate ve ion and the resin ROH is added in it the following
reaction takes place
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Raw
wate Cation bed DegaserAnion
bed
Mixed
bedDemir
water
BoilerBoiler is used to produce steam .
Law on which it works
It works on the basis of 2nd
law of thermodynamics which states that thermal energy is
converted in to mechanical energy, and Charles law ,boyles law and gas law.
Purpose
1. heating medium
2. turbine
Steam types
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Steam produced is of two types saturated and super saturated .the steam which is below its
critical temperature is called wet steam it contains traces of moisture and steam above critical
temperature is dry steam it doesntcontain any moisture .the boiler is mainly of two type .
Boiler types
1. fire-tube boiler
2. water tube boiler
Fire tube boiler contains hot gases inside the tube and water inside the shell side .where as
water heat boiler contains water inside the tube and hot gases out side the tube
Description
Boiler used in nimir chemicals is fired tube boiler it is made by German company SILLER AND
JAMART TECHNISCHE DIENSTE .it is package type 3- pass boiler .with the heating capacity of 8
ton /hr (eigth ton of steam generate from water per hour ) and produce the steam at a
pressure of 28 bar at temperature 340 degree centigrade .the basic purpose to produce steam
is for heating medium and run the turbine and the level is maintain above 60 if it is less then
chances of explosion take place .it is the 1st
class of boiler with heating surface area 22006
sqr/fts.the length of tube is about 20 fts and dia of tube 3 inches .the boiler get trip due to
following reasons
Triping reasons
1 low air pressure
2 low oil pressure
3 low Gas pressure
4. high steam pressure
Burner
1. Natural gas
2. Diesel
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Working of boiler
Demin water is used in the boiler . fuel is mixed with air and it is burnt in burner the hot gases
pass through the first stage where it heat the water .then it is pass through tubes of 2 pass and
further heat the water and produces saturated steam and then this steam is sent to pre heaterand convert into super heated steam .this steam is then sent in to plant and then it is used
where it required.
C) turbine
A steamturbine is a device that extractsthermal energy from pressurizedsteam and uses it to
domechanical work on a rotating output shaft.
D) compressor
It is a device which is used to compress the gas and increase it pressure.
Principle
It operate on Boyleslaw which state that volume is inversely proportional to the pressure.
V inversely proportional to pressure
Description
The compressor used in nimir chemical is made by MANNESMANN DEMAG Company Germany. It is
positive displacement compressor .two stages double acting compressor with 4 suction valve and 4
discharge valve .in the first stage air is compressed due to this temperature is increased and for this
purpose an inter cooler is attached with it to reduce the increase in temperature .In the second stage
the air is further compressed and then passing through cooler .it is then store in the main tank .the air is
then pass through drier to remove moisture .the compressed air produced is used for 2 different
purposes .
Plant air
Instrument air
Triping of compressor
Interruption fan
Oil pressure
Over heating motor
http://en.wikipedia.org/wiki/Turbinehttp://en.wikipedia.org/wiki/Thermal_energyhttp://en.wikipedia.org/wiki/Steamhttp://en.wikipedia.org/wiki/Work_(physics)http://en.wikipedia.org/wiki/Work_(physics)http://en.wikipedia.org/wiki/Steamhttp://en.wikipedia.org/wiki/Thermal_energyhttp://en.wikipedia.org/wiki/Turbine -
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Over heating water
Over heating air
e) Nitrogen
Two sources for the nitrogen is used in nimir
1, nitrogen from air
2, liquid nitrogen
F) Cooling tower
The basic function of cooling tower is cool down the hot water from the plant where it necessary. It is
basically a cooling medium.
Types of cooling tower
Natural
Mechanical
Mechanical is further divided into two categories
Induced draft
Forced draft
They are further divided on the basis of their flow
Co-current
Counter
Cross
Description
The cooling tower used in nimir chemical is forced draft. And the flow is cross which mean that water is
introduced from the top and air from fans is introduced from the side.Differnt chemicals is used in it for
different purposes.
Sulphuric acid
It is added to maintain the PH round about 6.5
Zinc chromate
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It is added to make thin film layer on pipe to prevent corrosion.
Sodium hypochlorite
It is added to kill the biological germs.
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8. Process and Production department
A.Phthalic anhydride (PA)
B.Maleic anhydride (MA)
C.Di-octyl phthalate (DOP)
A)Phthalic anhydride (PA)
This colourless solid is an important industrial chemical, especially for the large scale production
ofplasticizers for plastics.
Appearance
White Flakes
Chemical Name of PA 1, 2 benzene di-carboxylic acid
Molecular formula C8H4O3
Molecular Weight: 148
Melting Point 131.9C
Boiling point 284.5C
Flash Point: 152C
Auto ignition Temperature: 570C
Appearance It is clear and colorless solid.
Raw Materials for PA:
1) Ortho-Xylene
2) Air
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Specifications
Sr.no Tests Limits
1 Solidification point 130.9 C
2 Colour (APHA) 20
3 Heat hazard at 250 C(APHA) 40
4 Purity by GC Min 99.85
5 Benzoic acid % 0.05
6 Sheild life /expiry 0.6 month
Chemical reaction
V205
C8H10 + 3O2 C8H4O3 + 3H2O
Process description
The reaction takes place in the fixed bed tabular reactor. The reactor is equipped with 5028
tubes. The tubes are filled with four layers of catalyst. But vanadium pentaoxide (V2O5) and
titanium dioxide (TiO2) are the main catalyst. In the oxidation of orth-oxylene in the presence
of a catalyst, the main reaction is the formation of phthalic anhydride and water by-products
are maleic anhydride, benzoic acid, Citra conic acid and aldhyde it is highly exothermic reaction.
The heat of reaction is removed by circulating molten salt, mixture of sodium nitrate and
potassium nitrate through the shell side of the reactor from bottom to top. A steam generator
is attached with the reactor for cooling the salt. Also an electrical heater for heating up the
reactor during startup.
Reaction gas cooling
The reaction mixture leaving the reactor at approximately 370C is allowed to pass through two
stage gas cooler, having three bundles of tubes, in first stage 30 bar steam is produced by
recovering heat of gases coming from reactor and in next stage water for boiler feed water is
preheated.
Switch condensers
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To recover phthalic anhydride (PA) from the product gases, the gas mixture is further cool
down in the switch condensers to a temperature at which the PA is completely condensed as
solid where asby-product gases remain in the gaseous form. Switch condensers are operated
by an automatic cycle timer so that the three condensers are on loading one is on melting at a
time. Switch condensers consist of finned tubes around which the reaction gas flows. The PA isseparated and deposits on the finned tubes of the condensers which are on cooling (loading) in
the form of crystals. While PA is melted from condenser and transfer to crude PA storage
vessel.
Pretreatment:-
Now Crude PA is subjected to pretreatment, this treatment is carried out at atmospheric
pressure and temperature is kept about 275C- 285C for dehydration as well as conversion of
certain by-products into compounds which can be separate easily in the upcoming distillation.
The pretreatment takes place in three vessels with an average retention time of 18 hours. Each
vessel is provided with agitator and the vapors of water, low boilers and PA formed , passes
through the condenser , vapors of PA condenses while water, low boilers and traces of PA is
sent to switch condensers for PA recovery.
Distillation Columns:-
a) Fore running column
b) Pure PA distillation column
The fore running column is equipped with 14 fixed valve trays and sieves separates the low
boiling components from PA. The low boilers mainly benzoic acid (BA), traces of water etc. are
collected in the residue vessel. The PA is leaving the column above a certain level by means of a
funnel and enters the pure PA distillation column.
Pure PA distillation column is equipped with 25 trays. Distillation is carried out under vacuum
pure PA is received in pure PA tank from where it is delivered to flaking or to liquid storage
tank. Purity of PA is ensured with 99.9% with color index hazen max. 20. The bottom product
from the pure PA column is further processed batch wise to recover PA in a residue
concentration system under vacuum. After residue concentration the residue is drained in the
residue vessel.
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Uses of PA
Phthalic anhydride is widely used in industry for the production of certaindyes. A
well-known application of this reactivity is the preparation of
theanthroquinone dyequinizarin by reaction with para-chlorophenol followed byhydrolysis of the chloride
The primary use of phthalic anhydride (PA) is as a chemical intermediate in the
production of plastics from vinyl chloride. Phthalate esters, which function as
plasticizers, are derived from phthalic anhydride. Phthalic anhydride has another
major use in the production of polyester resins and other minor uses in the
production of alkyd resins used in paints and lacquers, certain dyes (anthraquinone,
phthalein, rhodamine, phthalocyanine, fluorescein, and xanthene dyes), insect
repellents, and urethane polyester polyols. It has also been used as a rubber scorch
inhibitor and retarder. Alkyd Resins (Glyptal), to modify physical properties of Synthetic Resins.
Phthalic anhydride is used to make halogenated anhydrides used as fire Retardants;
pigments; dyes; perfumes; pharmaceuticals; tanning and curing Agents; solvents;
insect repellents.
http://en.wikipedia.org/wiki/Dyeshttp://en.wikipedia.org/wiki/Anthroquinonehttp://en.wikipedia.org/wiki/Quinizarine_Green_SShttp://en.wikipedia.org/wiki/Quinizarine_Green_SShttp://en.wikipedia.org/wiki/Anthroquinonehttp://en.wikipedia.org/wiki/Dyes -
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B)maleic anhydride (MA)
Appearance
Moltan colorless liquid or white solids .penetrating odor.sinks and mixer slowly with water.
Physical properties
Chemical name 2-5 furandione
Molecular formula C4H2O3
Molecular weight 98.06
Boiling point 202 degree C
Melting point 52.4 degree C
Thermal decomposition >=2oo degree C
Flash point 101.7 degree c
Auto ignition temperature 475 degree c
Hazard identification
Health hazards
Liquid or solid will burn skin and eyes .skin contact cause irritation and redness.harmfull if
swallowed .inhalation causes coughing. Sneezing and throat irritation, vapour cause severe eye
irritation ,photophobia and double vision may occur.
Specifications
Sr.no Tests Limits
1 Solidification point 52.4 C2 Maleic acid(%)
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PROCESS DESCRIPTION
The wash water of the off-gas scrubber in the adjacent PA-Plant contains maleic acid, Citra
conic acid, benzoic acid, phthalide, orthotolaldehyde and traces of phthalic acid. The maleic
anhydride from solution of different organic compounds as mentioned before is recovered in
the maleic anhydride recovery plant in a two-stage distillation system.
1) Dehydration
For the recovery of maleic anhydride (MA) dissolved in the wash water of the off-gas scrubber
the free and chemical bonded water have first to be separated from the organic compounds,
such as maleic acid, phthalic acid and others. This is done in an azeotropic distillation using
orthoxylene (OX) as entertainer.
The column is equipped with 19 sieve trays. The solution from scrubber first passed through
crystallizer for the recovery of pthalic anhydride and then passing it through filter to remove
(PA) crystals in the form of cake and remaining solution is fed to the 15th
tray of dehydration
column. The necessary heat for dehydration is supplied in reboiler by SM steam.
The overhead vapors (ortho-xylene and water) are condensed in condenser and cooled in
cooler using cooling water. The mixture is separated in separator from where the orthoxylene
(OX) is fed as reflux to the column.
2) MA-Distillation
MA-distillation consists of packed column. The bottom product of the dehydration column,
consisting of maleic anhydride, ortho-xylene, Citra conic anhydride, phthalic anhydride etc, is
collected in the intermediate tank. This tank is equipped with an agitator to prevent settling of
solids. The mixture of compounds from intermediate tank is fed to the pure MA-distillationcolumn and separated batch-wise.
There are 5 stages in this column which are mentioned below:
1) Ortho-Xylene recovery (1st
Stage)
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2) Ortho-Xylene recovery (2nd
Stage) low boiling fraction with residual Orthoxylene
3) Pretreatment
4) Pure MA Recovery
5) Residue concentration
After residue concentration the residue is drained in the residue vessel.
Uses of Maleic Anhydride:
It is used in the formation of Unsaturated polyester resins and alkyd resins ,used
in general construction, bathroom fixtures, corrosion resistant tank, pipes and
ducts, electrical components, synthetic marble, paints and coatings,fibre glassreinforced plastic.
Used in the manufacturing of fumaric and malic acid, they are used in paper
sizing resins and beverage acidulants and in pharmaceuticals.
Used in the manufacturing of lubricating oil additives which are used in gasoline
and diesel engine crankcase oils as dispersants and corrosion inhibitors, prolong
oil change intervals and improve the efficiency of automotive engines.
The addition of maleic anhydride to drying oils decreases the required drying
time and improves the coating quality of lacquers.
It is used in making vinyl copolymers that are used in paper treatment, emulsifier,stabilizing agents, adhesives, detergents, cosmetics etc.
Its use in agricultural chemicals like herbicides, pesticides, plant growth regulator
and soil sterilizer.
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C) Di-Octyl phthalate (D.O.P)
DOP is produced by esterification process, it is highly compatible with PVC and has an excellent
plasticizing effect and has average characteristics of various plasticizers. In PVC processing the
consumption of DOP is the highest among all plasticizers.
Appearance
Clear
Colorless oily liquid
Water like appearance
Faint odor
Physical properties
Chemical name 1,2 benzene di carboxylic acid (2-ethyl hexyl )ester
Molecular formula C24H38O3
Molecular weight 390
Melting point - 50.0 degree C
Boiling point 230. Degree c
Specific gravity 0.986
Stability stable under ordinary condition
Flash point 199 degree c
Auto ignition temperature 390 degree c
Toxicity Oral rat LD50: 30 gm/kg
Hazard identification
Main hazards
Possible risk of impaired fertlilty .possible risk of harm to the unborn child.
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Health hazards
Eyes : liquid or mist may cause slight transient irritation
Skin : prolong or repeated contact with skin may cause slight irrition
Inhalation :exposure to vapors at higher concentrations may cause irritation of nose .throat
,and respiratory tract.
Raw material for DOP
Pthalic anhydride
2 ethyle hexanol
Chemical reaction
C8H4O3 + 2C8H18O C24H38O4 + H2O
(Pthalic anhydride) (2-ethyl hexanol) (DOP)
(Water)
Spacification of DOP
Sr .no Tests Limits
1 Acid value 0.02
2 Moisture content 0.053 Purity by GC Min 99.7
4 Appearance Clear
5 Colour Max 30
6 Specific gravity 0.986+0.02
Process description
Major sections
1. Mono-ester
2. Reactor
3. Stripper
4. Crude
5. Filtration unit
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1.Mono-ester
In mono-ester 2-ethyl hexanol is charged from main storage tank T-431, to heat alcohol up to
90C for approximately 1 hour and then sent to reactor for reaction with phthalic anhydride
(PA).
2) Reactor
In reactor charge phthalic anhydride from main storage tank to react with alcohol to form
mono-ester in the presence of tetra isopropyl titanate Ti (OC3H7)4 as catalyst at 220C
temperature. Reaction needs 6 hours for completion to get the required Acid value (A.V) 0.2 mg
KOH/g of sample. After this, product is shifted to Stripper.
3.Stripper
This is used to remove unreacted alcohol and by product water. For this there are nine steps to
get the required steps in DOP like low acid value ( 0.02 g KOH ), low moisture content (0.05 %)
,color 15-20 APHA( American physical health association) and no smell of alcohol.it contain 9
steps
a)Vacuum Stripping
Create a vacuum in stripper up to 0.15mbar pressure for 45minutes to remove alcohol and
water. In this procedure 85% of alcohol will be removed.
b)Steam Stripping
Now inject steam at 3.5 bar having temperature 200C with flow rate 600kg/hr for 80minutes
to remove remaining alcohol and water. It will increase the temperature of crude DOP in
stripper to 175-180C.Now break vacuum with nitrogen.
c) Cooling
After steam stripping now start cooling to cool the crude DOP up to 105C by the help of shelland tube condenser and air cooler.
d) Dosing
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Now add (10kg NaOH + 400 liter water) solution by creating vacuum up to 0.9mbar to make
salt of phthalic anhydride which had not reacted with alcohol to form DOP After this break
vacuum.
e) Agitation
Start agitation for 30min to homogenize the material and for complete reaction of phthalic acid
with caustic soda.
f) Settling
Stop agitator for 30 min to settle down, water, alcohol etc.
g) Draining
Remove water by opening drain line valve.
h) Heating
Now start heating under vacuum of 0.15mbar to rise the temperature of the material up to
155C, this process will take about 45min.Now stop heating and start steam stripping for 30 min
to remove moisture content (M.C) and traces of recycle alcohol.
i) Sample
Now sample of crude DOP is sent to laboratory for testing if the results will be according to our
requirement e.g. acid value(A.V) should be 0.02g KOH , moisture content(M.C) 0.05%, color
15APHA.Now product is ready for filtration.
4) Filtration Process
a) Filling with precoat susp
First of all fill the filtrate vessel with crude DOP and add resin (in the powder form) which iscalled as precoating susp.
b) Precoating
Now start filtration of the material in filtrate vessel by shifting it into filtration unit for
precoating of Socks on candles.
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c) Bleeding
In this step we shift the filtered DOP from filtration unit to filtrate vessel for precoating of
candles in next batch.
d) Filtration
In this step filtration of crude DOP is done.
e) Emptying
In this process empty the filtration unit by shifting the DOP back to crude vessel When socks
will block due to cake formation and more DOP can not be filtered.
f) Drying
Dry the filtration unit by injecting air at 6.5 bar pressure for 18 min.
g) Depressurizing
Depressurize the system by stopping the injection of air and open a vent.
h) Removal of cake
Inject air in socks at 7bar pressure and depressurized then pressurized the system again, repeatthis step 3-4 times , cake will left the socks free, now remove the remaining cake manually.
i) Depressurize
In this step UV 3420 will open for vent to depressurize the system again.
Uses of DOP
It is used in Versatile Plasticizer, Used in Plasticizing Poly Vinyl Chloride (PVC)
Binder in Paints, Pigmented and Unpigmented Lacquers and for Grinding Pigments.
DOP is used as a dielectric fluid in electric capacitors.
DOP is used as the solvent in erasable ink, as an inert ingredient in pesticides, as vacuum
pump oil.
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DOP is used as a Plasticizer in PVC resins for fabricating flexible vinyl product like:
tablecloth, shower, curtain, raincoat, shoes, swimming pools liners, polymeric coating,
cable coating, component of paper & paperboard, deforming agents, surface lubricants
Block diagram of DOP
Fumes
Of 2EH
r
2-EH
P-14
Kiquid 2-EH
P-20
P-21
P-27
F-311
Mono-
ester
Rea
ctor
D-
321
stripperCrude
vessel
F-341D-
331
Ejector
dr
u
m
Slope
vesse
condenserCondenser
condenser
Separator
Heat
Exchanger
Filter
Sepa
rator
Recylce
alchol
Recylce
alcholStor
agetank
Storag
e tank
Li
qu
id
2-
EH
hT IN
Ht
out
PA
Dosing of
NAOH
Recyle alcohol
Liq DOP
Crude DOP
H20
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