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HEMICAL
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Chemical
Chemical Technology
Chemical Technology
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Chemical Technology
Chemical Technology
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Last updated: Apr 1, 2009 pdated: Apr 1, 2009 2:46 PM2:46 PM
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Chemical Pmical Process Selection, Design and Operationrocess Selection, Design and Operation
Adequate and flexible initial design is essential for the promotion of a chemical plant organic product or Adequate and flexible initial design is essential for the promotion of a chemical plant organic product or inorganic product.
inorganic product.
In older days it was classified as inorganic chemical technology and organic chemical technology. In older days it was classified as inorganic chemical technology and organic chemical technology. Subsequently the oxford university made it as chemical works organization and management. Subsequently the oxford university made it as chemical works organization and management. Some factors that must be considered in planning a plant are discussed in this section. The Process Some factors that must be considered in planning a plant are discussed in this section. The Process
Engineer is an expert in the current aspects of chemical process design. Practical experience is a must if Engineer is an expert in the current aspects of chemical process design. Practical experience is a must if the senior design engineer is able to foresee and solve the problems of production, such as maintenance, the senior design engineer is able to foresee and solve the problems of production, such as maintenance, safety and obeying the government, environmental by loss and control.
safety and obeying the government, environmental by loss and control.
Experience consultants either individuals or professional consulting firms are able to advise, design and for Experience consultants either individuals or professional consulting firms are able to advise, design and for erection of chemical plants.
erection of chemical plants. Che
Chemical Prmical Process Control and Instrumentationocess Control and Instrumentation Automatic and Instrument contr
Automatic and Instrument control chemical processes are commol chemical processes are common and essential. Instruments shoulon and essential. Instruments should notd not be chosen simply to record a variables, of the process. But their function is to assure consistent quality by be chosen simply to record a variables, of the process. But their function is to assure consistent quality by sensing controls, recording and maintaining desired operating conditions. Instruments are the essential sensing controls, recording and maintaining desired operating conditions. Instruments are the essential tool for modern
tool for modern processprocesses. They are classified ases. They are classified as 1.
1. Indicating Indicating Instruments Instruments 2. 2. Recording Recording Instruments Instruments 3. 3. ControllControlling ing InstrumentsInstruments Two types of Instruments are currently used as analogue and digital.
Two types of Instruments are currently used as analogue and digital.
Analogue Instruments such as pressure spring thermometers and Bourden Gauges shows results by Analogue Instruments such as pressure spring thermometers and Bourden Gauges shows results by mechanical moments of some type of device which is directly proportional to the quantity measured. mechanical moments of some type of device which is directly proportional to the quantity measured. On the other hand, digital devices are converts the quantity measured into a signal and electric circuits On the other hand, digital devices are converts the quantity measured into a signal and electric circuits converts the signal to read the numerical values forward by control. Now the computers can monitor and converts the signal to read the numerical values forward by control. Now the computers can monitor and regulate outputs from both the analogue and digital devices according to a prearranged program, also regulate outputs from both the analogue and digital devices according to a prearranged program, also general conventional digital inputs are required. Chemical analytical control has been used in day to day general conventional digital inputs are required. Chemical analytical control has been used in day to day factory procedures for analysis of incoming raw material or outgoing products. Thus quality chemicals are factory procedures for analysis of incoming raw material or outgoing products. Thus quality chemicals are produced more in these days reliably their when human analysed control were used.
produced more in these days reliably their when human analysed control were used. The latest advancement are
The latest advancement are the chromatography system, many specthe chromatography system, many spectroscopy have been automated antroscopy have been automated an install of on-line basis for the process to run continuously without the problems encountered manually install of on-line basis for the process to run continuously without the problems encountered manually before.
before. Role o
Role of Cf Chemical Engineershemical Engineers
Chemical Engineers are trained primarily to work in chemical industries. some of the vital role of the Chemical Engineers are trained primarily to work in chemical industries. some of the vital role of the chemical engineers are as follows;
chemical engineers are as follows; Chemical Process Economics Chemical Process Economics
Engineer are totally different from Scientist by their customers of cost of production and profit generator. Engineer are totally different from Scientist by their customers of cost of production and profit generator. Therefore the objective of engineer should be to deliver safely the best product or most efficient service at Therefore the objective of engineer should be to deliver safely the best product or most efficient service at lower cost to the employer and the public who consumes the product.
lower cost to the employer and the public who consumes the product. Material Balance
Material Balance
Yield and conversion are the chemical prospects from the basis for the material balances which is useful for Yield and conversion are the chemical prospects from the basis for the material balances which is useful for cost determination.
cost determination.
Materials and their quantities from the standard practices are tabulated in the flow charts, energy given Materials and their quantities from the standard practices are tabulated in the flow charts, energy given are observed for the chemical reactions and energy is frequently a major cost in chemical plants but it are observed for the chemical reactions and energy is frequently a major cost in chemical plants but it often possible by altering the process procedures by using modern separation technologies like “RO” and often possible by altering the process procedures by using modern separation technologies like “RO” and “Advanced Separation Processes” to produce high quality chemicals with low energy consumption.
Plant Location Plant Location
The location of the chemical plant is decided ourselves by the availability of raw materials, transportation, The location of the chemical plant is decided ourselves by the availability of raw materials, transportation, market and power. Now the environmental constituents, water supply, availability of efficient labor, cost of market and power. Now the environmental constituents, water supply, availability of efficient labor, cost of land and waste disposal facilities form the criteria for the plant location.
land and waste disposal facilities form the criteria for the plant location. Construction of Plant
Construction of Plant
For small and large companies construction engineering organizations are available that will built a plant For small and large companies construction engineering organizations are available that will built a plant and participate in its design. Some large chemical companies have their own civil construction department and participate in its design. Some large chemical companies have their own civil construction department and starts their own plants.
and starts their own plants.
The advancement of this is the worker who is going to operate the equipment can be more intimately The advancement of this is the worker who is going to operate the equipment can be more intimately corrected to the constructions and be familiar themselves for the future alternatives, expansion or corrected to the constructions and be familiar themselves for the future alternatives, expansion or modifications.
modifications.
In built-in plants the top engineers are chartered engineers qualified for the development activities. They In built-in plants the top engineers are chartered engineers qualified for the development activities. They have been trained and suitably examined to guarantee technical competency and owe personal
have been trained and suitably examined to guarantee technical competency and owe personal
responsibility. They are now called as functional consultants and registered firm for dealing with legal responsibility. They are now called as functional consultants and registered firm for dealing with legal aspects with proper training.
aspects with proper training. Research and Development Research and Development
adequate and skilled research with patent protection is necessary for future profits. In the chemical adequate and skilled research with patent protection is necessary for future profits. In the chemical process industries one of the
process industries one of the outstanding tactics is rapidly changing processes, new raw materials and neoutstanding tactics is rapidly changing processes, new raw materials and ne ww markets. Research creates these changes and the factory will have a competitive progress. This research markets. Research creates these changes and the factory will have a competitive progress. This research brings about development and the
brings about development and the adoption of ideas, concepadoption of ideas, concepts, methodologies form the production of thts, methodologies form the production of thee industry. The results and benefits of research establishes the developing coutry on the road of progress industry. The results and benefits of research establishes the developing coutry on the road of progress and raise the level of life of common man.
and raise the level of life of common man. Che
Chemical Engineer in comical Engineer in coming yearsming years
Resources particularly energy and feed back for the Fertilizers and Heavy Chemical Industries. Resources particularly energy and feed back for the Fertilizers and Heavy Chemical Industries. 1.
1.
Infrastructure for Transportation and Telecommunications. Infrastructure for Transportation and Telecommunications. 2.
2.
Protection of the Environment. Protection of the Environment. 3.
3.
Development of Agro Industries where utilization of waste from Agro industries and exploitation of Development of Agro Industries where utilization of waste from Agro industries and exploitation of value
value added products from wastes.added products from wastes. 4.
4.
Transformation of Rural Economy, Industrialization and Privatization where the profits are less and Transformation of Rural Economy, Industrialization and Privatization where the profits are less and consumption is more.
consumption is more. 5.
5.
Problems of less Technical context are, Problems of less Technical context are, 6.
6.
The latest research and development have classified the following new industries; The latest research and development have classified the following new industries;
Cryogenics in Chemical Technology Cryogenics in Chemical Technology
1. 1.
Chemicals from Sea Chemicals from Sea
2. 2.
Air as a Chemical Raw Material Air as a Chemical Raw Material
3. 3.
NUPLEXES ( Nuclear Power Agro Industrial Complexes ) NUPLEXES ( Nuclear Power Agro Industrial Complexes )
4. 4.
Proteins from Petroleum Fermentation and Single Cell Proteins from Animal horns. Proteins from Petroleum Fermentation and Single Cell Proteins from Animal horns.
5. 5. Food Industries Food Industries 6. 6. Coal Chemicals Coal Chemicals 7. 7. Newer Petrochemicals Newer Petrochemicals 8. 8. Pesticides Pesticides 9. 9. Pharmaceuticals Industries Pharmaceuticals Industries 10. 10. Metallurgical Industries Metallurgical Industries 11. 11.
Water treatment & Air Pollution Control Water treatment & Air Pollution Control
12. 12.
The chemica
The chemical l procprocess industry had ess industry had its growth its growth from pre from pre scscientific chemicaientific chemical l industries followeindustries followed by d by scscientificientific che
chemicmical al induinduststry. ry. The The grogrowtwth h witwith h restrestrainsrains, , greegreen n chachallengllenge e to to chechemicmical al indusindustry try and the and the momoderndern separations process involved in the indian chemical industry seen today.
separations process involved in the indian chemical industry seen today.
We define Chemical Engineering as a synthesis of chemistry and engineering. A Chemical Engineering We define Chemical Engineering as a synthesis of chemistry and engineering. A Chemical Engineering therefore carries out on a large scale reactions developed in the laboratory by the chemist.
therefore carries out on a large scale reactions developed in the laboratory by the chemist.
The Major Areas of Work within Chemical Engineering are, The Major Areas of Work within Chemical Engineering are,
Research Research
Process Development Process Development
Process Design Process Design Evaluation of Design Evaluation of Design Plant Design Plant Design Construction Construction Production Supervision Production Supervision Plant Technical Services Plant Technical Services Sales of the Product Sales of the Product
The
The ResResearcearch h is is dividdivided ed into into three three cacategtegories like ories like FundFundamamentaental l ResResearcearch, h, ExpExploratloratory ory ResResearcearch h andand Process Research.
Process Research.
S
S..NNoo.. IInndduussttrryy TTyyppiiccaal l PPrroodduuccttss EEnnd d UUsseerr
1
1 IInnoorrggaanniic c CChheemmiiccaalls s HH22SOSO44 Fertilizers, Chemicals,Fertilizers, Chemicals, Petroleum Refining, Paints, Petroleum Refining, Paints, Pigments, Metal Processing Pigments, Metal Processing and Explosives
and Explosives
HNO
HNO33 ExplosExplosives & Ferives & Fer tilizerstilizers
N
NaaOOHH RRaayyoonn, , FFiillm m PPrroocceessssiinngg,, Petroleum Refining, Pulp & Petroleum Refining, Pulp & Paper Industry, Lye, Cleaners, Paper Industry, Lye, Cleaners, Soap & Detergents, Metal Soap & Detergents, Metal Processing
Processing
2
2 OOrrggaanniic c CChheemmiiccaallss AAcceettiic c AAnnhhyyddrriiddee RReessiinnss, , PPllaassttiiccs s & & NNyylloonn
E
Etthhyyl l AAllccoohhooll AnAnttiiffrreeeezze e aaggeennttss,,
Cellophane, Dynamite & Syn. Cellophane, Dynamite & Syn. Fibres
Fibres
F
Foorrmmaallddeehhyyddee PPllaassttiiccss
M
Meetthhaannooll MMffrr. . OOf f FFoorrmmaallddeehhyyddee,, IMS(Industrial Methylated IMS(Industrial Methylated Solvent) & Antifreeze agent Solvent) & Antifreeze agent
3
3 PPeettrroolleeuumm& & Petrochemicals Petrochemicals
G
Gaassoolliinnee MMoottoor r FFuueellss
K
Keerroosseennee FFuueell
O
Oiill LLuubbrriiccaattiioon n & & HHeeaaddiinngg purposes
purposes
A
Ammmmoonniiaa FFeerrttiilliizzeer r & & CChheemmiiccaallss
E
Etthhaannooll AAcceettaallddeehhyydde e ssoollvveenntts s & & other miscellaneous chemicals other miscellaneous chemicals
A
S
Sttyyrreennee SSyynn. . RRuubbbbeerr, , PPoollyymmeerrs s & & Plastics
Plastics
4
4 PPuullp p & & PPaappeerr PPaappeerr BBooookkss, , RReeccoorrdds s & & NNeewwssppaappeerr
C
Caarrddbbooaarrdd BBooxxees s ffoor r ppaacckkiinngg
F
Fiibbeer r BBooaarrdd BuBuiillddiinng g mmaatteerriiaallss
5
5 PPiiggmmeenntts s & & PPaaiinnttss ZZiinnc c OOxxiidde e ((ZZnnOO)) PPiiggmmeenntts s ffoor r ppaaiinnttss, , iinnkkss,, plastic, rubber, ceramics and plastic, rubber, ceramics and linoleum
linoleum TiO
TiO22
C
Caarrbboon n BBllaaddee DDrryyiinng g OOiill
Lead Chromate Lead Chromate
Linseed Oil Linseed Oil
P
Phheennoolliic c RReessiinnss BBaassiic c kkeeqquueer r wwaarrmmiissh h & & enamels
enamels
A
Allkkyyl l RReessiinnss IIoon n eexxcchhaanngge e rreessiinns s aanndd constituents of enamel constituents of enamel
6
6 RRuubbbbeerr NNaattuurraal l RRuubbbbeerr((IIssoopprreennee)) AAuuttoommoobbiille e ttyyrreess, , mmoouullddss,, sheets, footwear and
sheets, footwear and insulation
insulation Syn. Rubber (Neoprene)
Syn. Rubber (Neoprene)
Butyl Rubber Butyl Rubber
7
7 PPllaassttiiccss PPhheennool l FFoorrmmaallddeehhyyddee VVaarriioouus s uusseerrs s iin n aalll l aarreeaas s oof f everyday life everyday life Poly Styrene Poly Styrene Polymethyl methacrylate Polymethyl methacrylate PVC PVC Polyethylene Polyethylene Polyster Polyster 8
8 SSyynntthheettiic c FFiibbeerrss RRaayyoonn CCllootthhiinngg
Nylon Nylon Acrylics Acrylics Polyster Polyster 9
9 MMiinneerraallss GGllaasss s & & CCeerraammiiccss WiinW nddoowwss, , ccoonnttaaiinneerrss, , bbrriicckks s & & pipe tubes
C
Ceemmeenntt CCoonnccrreette e ffoor r ccoonnssttrruuccttiioon n oof f buildings, highways, etc. buildings, highways, etc.
C
Cooaall FFuueellss, , cocokke e aannd d iittss by-products
by-products
1
100 CClleeaannssiinng g AAggeennttss SSooaapps s & & DDeetteerrggeennttss HHoouusse e hhoolld d cclleeaanniinng g & & Industrial cleaning. Sodium Industrial cleaning. Sodium alkyl aryl sulfonate is also alkyl aryl sulfonate is also used as wetting agent. used as wetting agent.
1
111 BBiio o CChheemmiiccaallss PPhhaarrmmaacceeuuttiiccaalls s & & DDrruuggss HHeeaalltth h & & MMeeddiicciinnee applications
applications
Fermentation product like Fermentation product like penicillin
penicillin
Medical use Medical use
E
Etthhyyl l AAllccoohhooll SSoollvveennt t aannd d BBeevveerraaggeess
F
Fooood d PPrroodduuccttss HuHummaan n ssuussttaannccee
1
122 MMeettaallss SStteeeell, , CCuu, , AAl l & & ZZiirrccoonniiuumm AAlll l tthhe e BBuuiillddiinng g mmaatteerriiaallss,, machinery etc.
machinery etc.
U
Urraanniiuumm NNuucclleeaar r ffuueell
The largest tonnage inorganic chemicals is H
The largest tonnage inorganic chemicals is H22SOSO4.4. It is consumed by industry in the manufacture of otherIt is consumed by industry in the manufacture of other products. Thereby it reaches the public knowledge vary scarely. Large quantities are consumed by
products. Thereby it reaches the public knowledge vary scarely. Large quantities are consumed by
petroleum and metal industries. The important organic chemical include alcohols, dyes, dye intermediates petroleum and metal industries. The important organic chemical include alcohols, dyes, dye intermediates used to produce other chemicals. Ethyl alcohol was initially produced by bio chemical fermentation before used to produce other chemicals. Ethyl alcohol was initially produced by bio chemical fermentation before the second world war.
the second world war.
But now it is produced primarily from petroleum on the latest discovery of natural gas. The important But now it is produced primarily from petroleum on the latest discovery of natural gas. The important petroleum products are gasoline, l
petroleum products are gasoline, l ubricants, petrochemicals, other fuels and ubricants, petrochemicals, other fuels and miscellaneous chemicals.miscellaneous chemicals. Since the second world war petrochemicals have assumed a commander role in the economy. The largest Since the second world war petrochemicals have assumed a commander role in the economy. The largest petrochemical ammonia is produced by reaction of H
petrochemical ammonia is produced by reaction of H22 from natural gas or petroleum with Nfrom natural gas or petroleum with N22 availabavailable ile inn the Air.
the Air.
This Ammonia reacts with CO
This Ammonia reacts with CO22 to producto produce Urea in e Urea in a fertilizer a fertilizer plant. Noplant. Normally there are five different unitsrmally there are five different units in the fertilizer manufacture from coal based mines.
in the fertilizer manufacture from coal based mines. Oil & Gasification plant
Oil & Gasification plant
1. 1.
Benfield De-sulphurization plant Benfield De-sulphurization plant
2. 2. Ammonia plant Ammonia plant 3. 3. CO CO22 plantplant 4. 4. Urea plant Urea plant 5. 5.
The tendency of Urea is to form BIURETS which are used as regenerator salts in the metallurgical The tendency of Urea is to form BIURETS which are used as regenerator salts in the metallurgical applications. Many plastics and synthetic detergents are produced with the help of oil refineries. applications. Many plastics and synthetic detergents are produced with the help of oil refineries.
Unit Operation Unit Operation
The basic physical operations of chemical engineering in a chemical process plant, that is distillation, fluid The basic physical operations of chemical engineering in a chemical process plant, that is distillation, fluid transportation, heat and mass transfer, evaporation, extraction, drying, crystallization, filtration, mixing, transportation, heat and mass transfer, evaporation, extraction, drying, crystallization, filtration, mixing, size separation, crushing and grinding, and conveying. In simple terms, the operation which involves size separation, crushing and grinding, and conveying. In simple terms, the operation which involves physical changes
physical changes are known as Unit Operation.are known as Unit Operation.
Distillation is a unit operation is used to purify or separate alcohol in the brewery industry. Distillation is a unit operation is used to purify or separate alcohol in the brewery industry.
1. 1.
The same distillation separates the hydrocarbon in a petroleum industries. The same distillation separates the hydrocarbon in a petroleum industries.
2. 2.
Dry grapes and other food products or similar drying of filter precipitate like rayon industry where Dry grapes and other food products or similar drying of filter precipitate like rayon industry where yarn is produced.
yarn is produced.
3. 3.
Abs
Absorporption of tion of oxyoxygen from gen from air air in in a a fermfermentaentation procetion process of ss of a a sewsewagage e treatreatmtment ent plaplant nt and half and half hydrogen gas in a process fr liquid hydrogenation of oil.
hydrogen gas in a process fr liquid hydrogenation of oil.
4. 4.
Evaporation of salts solutions similar to evaporation of sugar solution in the industry. Evaporation of salts solutions similar to evaporation of sugar solution in the industry.
5. 5.
Settling and sedimentation of suspend solids similar to minimizing and sewage treatment plant. Settling and sedimentation of suspend solids similar to minimizing and sewage treatment plant.
6. 6.
Flo
Flow w of liquid hydof liquid hydrocrocarbarbon on in in a a pepetrotroleuleum m refrefinerinery y and floand flow w of milk of milk in in a a dadaily ily plplant for ant for thethe solidification in spray dryer.
solidification in spray dryer.
7. 7.
Cla
Classification of ssification of Unit OperationsUnit Operations Fluid Flow
Fluid Flow : Concerns the principle that determine the flow or transformation of fluids from one: Concerns the principle that determine the flow or transformation of fluids from one point to another. The fluid can be a liquid or a gas. This unit is entirely based on Bernoulli e's point to another. The fluid can be a liquid or a gas. This unit is entirely based on Bernoulli e's equation followed by continuity correlation.
equation followed by continuity correlation.
1. 1.
Heat Transfer
Heat Transfer : Deals with principles that govern accumulation and transfer of heat and energy: Deals with principles that govern accumulation and transfer of heat and energy from one place to another. The three concepts followed here are conduction, convection and from one place to another. The three concepts followed here are conduction, convection and radiation.
radiation.
2. 2.
Evaporation
Evaporation : A special case of heat transfer which deals with the evaporation of volatile solvent: A special case of heat transfer which deals with the evaporation of volatile solvent such as waste from a non-volatile solute such as salt or any other material in the solution. The such as waste from a non-volatile solute such as salt or any other material in the solution. The
evaporation of trichloro-ethylene a cleaning agent in the automobile service industry and acetone in evaporation of trichloro-ethylene a cleaning agent in the automobile service industry and acetone in the case of glassware in a chemical process industries follow this unit operations.
the case of glassware in a chemical process industries follow this unit operations.
3. 3.
Drying
Drying : An operation in which volatile liquids (usually water) are removed from solid material.: An operation in which volatile liquids (usually water) are removed from solid material.
4. 4.
Distillation
Distillation : An operation where a components of the liquid mixture are separated by boiling: An operation where a components of the liquid mixture are separated by boiling because of their difference in vapor pressure.
because of their difference in vapor pressure.
5. 5.
Absorption
Absorption : A process whereby a component is removed from gas mixture : A process whereby a component is removed from gas mixture by treatment withby treatment with liquid.
liquid.
6. 6.
Liq-Liq Extraction
Liq-Liq Extraction : A process in which a solute in a liquid solution is removed by contact with: A process in which a solute in a liquid solution is removed by contact with another liquid solvent that is relatively ir
another liquid solvent that is relatively ir reversible with solution.reversible with solution.
7. 7.
Liq-Solid Leaching
Liq-Solid Leaching: It involves treating a finely divided solid with a liquid that dissolves and: It involves treating a finely divided solid with a liquid that dissolves and removes a solute contain in the solid.
removes a solute contain in the solid.
8. 8.
Crystallization
Crystallization : The removal of a solute such as a salt from solution by precipitation in the: The removal of a solute such as a salt from solution by precipitation in the industries for large scale operations, electrostatic precipitation is operated for this concept. industries for large scale operations, electrostatic precipitation is operated for this concept.
9. 9.
Mechanical physical separation
Mechanical physical separation : This involv: This involves separation of solids, liquids or gases by mechanicales separation of solids, liquids or gases by mechanical means such as filtration, settling, size reduction which are classified as separate unit operations. means such as filtration, settling, size reduction which are classified as separate unit operations.
10. 10.
The outline of unit operation defines the settling tanks for sedimentation, filter press for The outline of unit operation defines the settling tanks for sedimentation, filter press for separations, pressurized spheres for ammonia storage, pellatising for fertilizer compounds, separations, pressurized spheres for ammonia storage, pellatising for fertilizer compounds, pneumatic c
pneumatic conveyors for cemonveyors for cement industry, bucket wheel ent industry, bucket wheel elevators for thermal power selevators for thermal power stationstations and belt conveyors for core industries and many more in operation.
and belt conveyors for core industries and many more in operation.
Stacks Stacks
Gases are discharged into the ambient atmosphere by stacks (referred to as chimneys in industry) of Gases are discharged into the ambient atmosphere by stacks (referred to as chimneys in industry) of several types.
several types.
The chemical process steps involved the foll
Preparing the Reactors Preparing the Reactors 1. 1. React them React them 2. 2.
Separate the Products Separate the Products 3.
3.
Purify the Products Purify the Products 4.
4.
The purpose of chemical industry is to start from one and other chemical raw material arrive at a The purpose of chemical industry is to start from one and other chemical raw material arrive at a
consumer product through a group of physical and chemical products. Therefore it is called as a creative consumer product through a group of physical and chemical products. Therefore it is called as a creative industry rather than assembly industry.
industry rather than assembly industry.
This mainly fall into inorganic, natural products, organic chemicals and metallurgical industry. This mainly fall into inorganic, natural products, organic chemicals and metallurgical industry.
Unit Processes Unit Processes
Processes that involve making chemical changes to materials, as a result of chemical reaction taking place. Processes that involve making chemical changes to materials, as a result of chemical reaction taking place. For instance, in the combustion of coal, the entering and leaving materials are differ from each other
For instance, in the combustion of coal, the entering and leaving materials are differ from each other
chemically. Coal and Air enters, and flue gases and residues leave the combustion chamber. Combustion is chemically. Coal and Air enters, and flue gases and residues leave the combustion chamber. Combustion is therefore a unit process. Unit processes are also referred to as chemical conversions. In simple terms, the therefore a unit process. Unit processes are also referred to as chemical conversions. In simple terms, the process which involves
process which involves chemical changeschemical changes are known as Unit Processesare known as Unit Processes..
Together with unit operations (physical conversions), unit processes (chemical conversions) form the basic Together with unit operations (physical conversions), unit processes (chemical conversions) form the basic building
building blocks of a chemical manufacturinblocks of a chemical manufacturing process. Mosg process. Most chemical processes consist of a combination of t chemical processes consist of a combination of various unit operations and unit processes.
various unit operations and unit processes.
1.
1. AlkylationAlkylation ::
Addition of alkyl radical (CH3) with side chain final product. This alkylation process is widely used Addition of alkyl radical (CH3) with side chain final product. This alkylation process is widely used in organic
in organic chemicals chemicals and petroleum industries. The and petroleum industries. The reaction is given asreaction is given as,, C=C-C-C + C-C-C
C=C-C-C + C-C-C
2.
2. Amination by AmmonolysisAmination by Ammonolysis::
Cl-CH
Cl-CH22CHCH22Cl + 4NHCl + 4NH33--->NH--->NH22CHCH22CHCH22NHNH22
EDC
EDC EthyEthylene lene DiamineDiamine
This reaction is used in manufacture of dye stuffs, organic chemicals and synthetic fibres. This reaction is used in manufacture of dye stuffs, organic chemicals and synthetic fibres.
3.
3. Amination by ReductionAmination by Reduction::
CH
CH33CHNOCHNO22CHCH33 + 3H+ 3H22 --->> CHCH33CHNHCHNH22CHCH33 2
2 Nitro Nitro Paraffin Paraffin Iso Iso PropylaminePropylamine
This unit
This unit process is also used in the manufacture process is also used in the manufacture of dye stuffs and organic chemicals.of dye stuffs and organic chemicals.
4.
4. Amino OxidationAmino Oxidation::
CH
CH33CHCH22CHCH33 + NH+ NH33 + 1.5 O+ 1.5 O22 --->> CHCH22:CHCN + H:CHCN + H2200 Propylene Acrylonitrile
Propylene Acrylonitrile
This reaction is used in the manufacture of plastics and synthetic fibres. This reaction is used in the manufacture of plastics and synthetic fibres.
5.
5. CalcinationCalcination ::
CaCO
CaCO33 ---HeatHeat--->> CaO + COCaO + CO22 Limestone Lime
Limestone Lime
This reaction is used in the cement industry. This reaction is used in the cement industry.
6.
6. CarbonylationCarbonylation::
CH
Methanol
Methanol Acetic Acetic AcidAcid
This is used in the manufacture of organic chemicals. This is used in the manufacture of organic chemicals.
7.
7. CarboxylationCarboxylation::
This reaction is used in the organic chemical industry. This reaction is used in the organic chemical industry.
8.
8. CombustionCombustion::
CH
CH44 + O+ O22 --->> COCO22 + 2H+ 2H22O O ( ( Process Process Heating Heating ))
9.
9. CondensationCondensation::
C
C66HH55CHO + CHCHO + CH33CHO ---CHO --->> CC66HH55CH:CHCHO + HCH:CHCHO + H22OO
Benzaldehyde+Acetaldehyde Cinnamaldehyde Benzaldehyde+Acetaldehyde Cinnamaldehyde
10.
10.CraCracking or Pyrolcking or Pyrol ysisysis::
C-C-C-C-C-C-C ---> C-C-C + C=C-C-C C-C-C-C-C-C-C ---> C-C-C + C=C-C-C
This reaction is used in petroleum destruction and distillation of coal. This reaction is used in petroleum destruction and distillation of coal.
1.
1. Fluid - Solid Fluid - Solid CContactontact::
Represented by fixed bed reaction. It is most widely used in catalytic reactor used with precious metal Represented by fixed bed reaction. It is most widely used in catalytic reactor used with precious metal catalyst to minimize attrition losses. The catalyst used in the form of pellets. It can represented by the catalyst to minimize attrition losses. The catalyst used in the form of pellets. It can represented by the following figure.
following figure.
This is used in the packed column. The design of the column is determined by the breakthrough curve, This is used in the packed column. The design of the column is determined by the breakthrough curve, equilibrium line for the given system of adsorbent and adsorbate's. The volume of the reactant coming equilibrium line for the given system of adsorbent and adsorbate's. The volume of the reactant coming from the top and the volume of which the product leaves the column, residence time, distribution decides from the top and the volume of which the product leaves the column, residence time, distribution decides the dimensions of the column. It is contrary to the fluid bed reactor where the bed is fluidized. Once the the dimensions of the column. It is contrary to the fluid bed reactor where the bed is fluidized. Once the minimum fluidized velocity is reached the porosity of the bed is faster in a fixed bed reactor but varies minimum fluidized velocity is reached the porosity of the bed is faster in a fixed bed reactor but varies from the fluidized bed where the porosity changes according to the height of the bed.
from the fluidized bed where the porosity changes according to the height of the bed.
2.
2. Fluid - Solid SeparationFluid - Solid Separation::(Centrifugation)(Centrifugation)
This operation separates very finely divided solids from liquid or mixture of liquid and liquid emulsion. This operation separates very finely divided solids from liquid or mixture of liquid and liquid emulsion.
3.
3. WWet Scrubbeet Scrubberr::
It is an effective
It is an effective means of removing suspended particles from gas string by contact with limeans of removing suspended particles from gas string by contact with li quid shower.quid shower.
When solids are used in the place of liquid the operation is called Dry Scrubber. In the manufacture of When solids are used in the place of liquid the operation is called Dry Scrubber. In the manufacture of MEK, wet scrubber is used and in other selected process industries Dry Scrubbers are used,
MEK, wet scrubber is used and in other selected process industries Dry Scrubbers are used, Scrubber just washes away the impurities and separate the product for further purification. Scrubber just washes away the impurities and separate the product for further purification.
4.
4. Filter PressFilter Press::
It is the simplest type of pressure filtration. the two important parts of the filter press are plates & It is the simplest type of pressure filtration. the two important parts of the filter press are plates & frames and fabric used in between the two are made of variety of corrosion resistant materials. In the frames and fabric used in between the two are made of variety of corrosion resistant materials. In the laboratory scales asbestos cloth are used for filtration at different pressures.
laboratory scales asbestos cloth are used for filtration at different pressures.
The operation decides the value of specific cake resistance, filter medium resistance and compressibility The operation decides the value of specific cake resistance, filter medium resistance and compressibility of the chemical nam
of the chemical namely Kieselghur ely Kieselghur a speca specific compific compound in the nature of diatomacceous ound in the nature of diatomacceous earth which areearth which are used in the application of bio-physics and cyrstallography.
used in the application of bio-physics and cyrstallography.
5.
5. Fluid StorageFluid Storage::
Tanks are widely used for storage of liquids of all types and atmospheric pressure when the liquid is Tanks are widely used for storage of liquids of all types and atmospheric pressure when the liquid is highly volatile there is a floating roof which acts as lid for chemicals as and when the vapour pressure at highly volatile there is a floating roof which acts as lid for chemicals as and when the vapour pressure at which signifying the boiling point of liquid the roof changes its position and deserves the liquid from going which signifying the boiling point of liquid the roof changes its position and deserves the liquid from going out to the atmosphere.
out to the atmosphere.
6.
6. Pressurized SpheresPressurized Spheres::
Pressurized spheres are used for pressurized storage of liquefied gases or high vapors. The pressure Pressurized spheres are used for pressurized storage of liquefied gases or high vapors. The pressure permits safe storage with no vapor losses. This is seen in the fertilizer plant where ammonia is stored in permits safe storage with no vapor losses. This is seen in the fertilizer plant where ammonia is stored in spheres.
7.
7. Gas-Gas-Liquid Liquid ContactContact:: (Absorption)(Absorption)
The best example is Absorption. It is used for taking a soluble gas in a solvent liquid and producing a The best example is Absorption. It is used for taking a soluble gas in a solvent liquid and producing a solution plus an exit gas. Hydrogen Sulphide is removed from hydrocarbon by the absorption process. solution plus an exit gas. Hydrogen Sulphide is removed from hydrocarbon by the absorption process.
8.
8. AdsorptionAdsorption::
It is classified into physiorption and chemisorption according to the process applied. The former one is It is classified into physiorption and chemisorption according to the process applied. The former one is almost a physical change or physical transformation while a later represents a chemical reaction which is a almost a physical change or physical transformation while a later represents a chemical reaction which is a irreversible one. the common effluent treatment plants of varies nature lied textile effluents, sewage
irreversible one. the common effluent treatment plants of varies nature lied textile effluents, sewage treatment, ETP plants in chemical industry, removal of hazardous solid wastes, etc are dealt with treatment, ETP plants in chemical industry, removal of hazardous solid wastes, etc are dealt with adsorption method and the adsorbent is regenerated over a period of time and used again and again. adsorption method and the adsorbent is regenerated over a period of time and used again and again.
9.
9. Heat ExchangersHeat Exchangers::
The various cooling towers of natural draft and forced draft are example of industrially applied H.Es. The various cooling towers of natural draft and forced draft are example of industrially applied H.Es. These are common facilities in the thermal power stations and in chemical industries the application of These are common facilities in the thermal power stations and in chemical industries the application of shell & tube heat exchangers are widely used. this is an excellent application of heat transfer from one shell & tube heat exchangers are widely used. this is an excellent application of heat transfer from one medium to the other.
medium to the other.
10.
10.Membrane SeparationMembrane Separation::
Dialysis is used to separate metals in solution having widely different molecular weight. for example Dialysis is used to separate metals in solution having widely different molecular weight. for example caustic from sugar solution or cellulose.
caustic from sugar solution or cellulose.
11.
11.Size ReductionSize Reduction::
This involves crushing, grinding, pelletizing and prilling. Pelletizing is used in pharmaceutical industries This involves crushing, grinding, pelletizing and prilling. Pelletizing is used in pharmaceutical industries and prilling used the manufacture of Urea.
Modern chemical processes are offer extremely complex operations involving 100s of pieces of equipment. Modern chemical processes are offer extremely complex operations involving 100s of pieces of equipment. without a systematic approach it would be i
without a systematic approach it would be imposmpossible to analyses an esible to analyses an existing process or to designxisting process or to design equipment process. The typical chemical process is analyzed with the following interdependent equipment process. The typical chemical process is analyzed with the following interdependent considerations like,
considerations like,
- Mass & Energy Balance - Mass & Energy Balance - Thermo chemistry - Thermo chemistry - Unit Operations - Unit Operations - Plant Equipment - Plant Equipment - Ancillary Equipment - Ancillary Equipment - Process Plant Diagram - Process Plant Diagram - Instrumentation Control - Instrumentation Control - Economics
- Economics
which deals with net profit before taxation profit after taxation dividend paid to the public and share which deals with net profit before taxation profit after taxation dividend paid to the public and share holders. Once the
holders. Once the process as process as been developed and completed attention been developed and completed attention can be made to accescan be made to accesss the various liabilities, resource and assets.
the various liabilities, resource and assets.
Alternatives and the remaining choices can be ranked in the order of desirability. They are as follows; Alternatives and the remaining choices can be ranked in the order of desirability. They are as follows;
- Effectiveness for reducing waste - Effectiveness for reducing waste - Technical Risk
- Technical Risk
- Extended of current views in the facility - Extended of current views in the facility - Industrial Precedent
- Industrial Precedent
- Capital and Operating cost incurred - Capital and Operating cost incurred - Effect of the Quality of the product - Effect of the Quality of the product - Impac
- Impact of Plant t of Plant OperationsOperations
- Required time for Implementation - Required time for Implementation
- Other aspects important in the particular situation according to the industrial - Other aspects important in the particular situation according to the industrial
Conservation of Energy Conservation of Energy::
dE
dE = = Q Q - - W W This This is is a a steady steady state state batch batch processprocess.. dH
dH = = Q Q - - Ws Ws Thia Thia is is for for flow flow processprocess..
Q--> Heat energy
Q--> Heat energy transfered across system boundary.transfered across system boundary. W-->Work ener
W-->Work energy transfered across system boundary.gy transfered across system boundary. Ws->Mec
Ws->Mechanical worhanical work energy k energy transfered across system boundary.transfered across system boundary. E--> Internal energy of the system.
E--> Internal energy of the system.
dE, dH--> Changes in Internal Energy & Enthalpy during the process. dE, dH--> Changes in Internal Energy & Enthalpy during the process.
we are already classified the various unit operations and below is a particular basic column of mass we are already classified the various unit operations and below is a particular basic column of mass transfer equipment.
1.
1. DistillationDistillation::
It is classified into Batch and Continuous Fractionation. It is classified into Batch and Continuous Fractionation. a.
a. Batch Fractionation:Batch Fractionation:
Used for intermittent operation and handling of small volume of feed and products. Used for intermittent operation and handling of small volume of feed and products.
b.
These are used for high volume continous seperation of complex mistures such as petroleum These are used for high volume continous seperation of complex mistures such as petroleum fractions connected to appropriate pumps, re-boilers, condensers, scrubbers, s
fractions connected to appropriate pumps, re-boilers, condensers, scrubbers, strippers and fintrippers and finallyally automatic controls.
automatic controls.
2.
2. Drying of SolidsDrying of Solids::
Spray Dryer , Rotary Dryer & Tunnel Dryer are some example of these types. Spray Dryer , Rotary Dryer & Tunnel Dryer are some example of these types.
3.
3. EvaporationEvaporation::
Open pan evaporators and multiple effect evaporators as used in sugar and salt industries for example. Open pan evaporators and multiple effect evaporators as used in sugar and salt industries for example. Among these halogen family we have technology to separate chlorine and fluride but production of
Among these halogen family we have technology to separate chlorine and fluride but production of bromine from the 'sea brine'is almost not put into practice as the bromine chemicals is highly corrosive bromine from the 'sea brine'is almost not put into practice as the bromine chemicals is highly corrosive and necessary precaution has to be laid out for practical purpose.
and necessary precaution has to be laid out for practical purpose.
4.
4. ExtractionExtraction::
Liquid - Liquid Extraction Liquid - Liquid Extraction
Solid - Liquid Leaching are examples for this process Solid - Liquid Leaching are examples for this process
5.
5. Fluid Handling EquipmentsFluid Handling Equipments:: Centrifugal pumps Centrifugal pumps Reciprocating pumps Reciprocating pumps Jet ejectors Jet ejectors 6.
6. Fluid - Solid Fluid - Solid CContactingontacting:: Fixed Bed
Fixed Bed Fluidized Bed Fluidized Bed Moving Bed, etc. Moving Bed, etc.
7.
7. Fluid - Solid SeparationFluid - Solid Separation:: Centrifugation
Centrifugation
Settling Tank / Sedimentation Settling Tank / Sedimentation Wet Scrubber / Dry Scrubber Wet Scrubber / Dry Scrubber Crystallization Crystallization Rotary Filter Rotary Filter Filter Press Filter Press Cyclone Separator Cyclone Separator Electro-static Preciptator Electro-static Preciptator Bag Filter Bag Filter
Thickeners based on Kynch Theory Thickeners based on Kynch Theory
8.
8. Fluid StorageFluid Storage::
Gas Holders Gas Holders Tanks Tanks Pressurized Spheres Pressurized Spheres
Underground Caverns which are used for the purpose of Natural Gas Storage. Underground Caverns which are used for the purpose of Natural Gas Storage.
9.
Absorption Absorption Stripping Stripping
10.
10.Heat ExchangersHeat Exchangers:: Fired Heaters Fired Heaters Re-boilers Re-boilers Condensers Condensers
Shell & Tube Heat Exchangers Shell & Tube Heat Exchangers Jacketed Kettle
Jacketed Kettle
Quenching applied in conventional Heat Transfer and Metallurgical Operations. Quenching applied in conventional Heat Transfer and Metallurgical Operations.
11.
11.Membrane SeparationMembrane Separation:: Dialysis Dialysis Gaseous Diffusion Gaseous Diffusion 12. 12.MixingMixing:: Agitation Agitation Solids Blending Solids Blending 13.
13.Size Reduction & EnlargementSize Reduction & Enlargement:: Crushing Crushing Grinding Grinding Pelletizing Pelletizing 14.
14.Solids HandlingSolids Handling::
Pneumatic Conveying - Juices transfered to 200 km in Brazil Pneumatic Conveying - Juices transfered to 200 km in Brazil Bucket Elevators - Coal Industries
Bucket Elevators - Coal Industries
Screw Conveyors - Tooth Paste, Turbine Liquids Screw Conveyors - Tooth Paste, Turbine Liquids Belt Conveyors
Belt Conveyors
15.
15.Solid - Solid Solid - Solid SepaSeparationration:: Screening
Screening Elutriation Elutriation Froth
Froth RotatRotationion Jigging
Jigging
Magnetic Separation Magnetic Separation
C
CHEMIHEMICCAL AL REACTORSREACTORS
The Reactor is the heart of the chemical process. The design of an industrial chemical reactor must satisfy The Reactor is the heart of the chemical process. The design of an industrial chemical reactor must satisfy the requirements in four main areas.
the requirements in four main areas.
Chemical Factors Chemical Factors
1. 1.
Mass Transfer Factors Mass Transfer Factors
2. 2.
Heat Transfer Factors Heat Transfer Factors
3. 3. Safety Factors Safety Factors 4. 4. 1. Chemical Factors: 1. Chemical Factors:
This involve the kinetics of the reaction weather it's first order or second order and based on this chemical This involve the kinetics of the reaction weather it's first order or second order and based on this chemical reaction engineering is built on the design must provide sufficient residence time to proceed the reaction reaction engineering is built on the design must provide sufficient residence time to proceed the reaction for the required degree of reaction and conversion to product.
for the required degree of reaction and conversion to product.
2. Mass Transfer Factors: 2. Mass Transfer Factors:
The reaction rate of homogeneous reaction may be controlled by the rate of diffusion of reactants rather The reaction rate of homogeneous reaction may be controlled by the rate of diffusion of reactants rather than the chemical kinetics of Langmuir isotherm and Frendlich isotherm.
than the chemical kinetics of Langmuir isotherm and Frendlich isotherm.
3. Heat Transfer Factors: 3. Heat Transfer Factors:
These describes weather the reaction is exothermic or endothermic. In Exothermic, heat is released These describes weather the reaction is exothermic or endothermic. In Exothermic, heat is released outside and In Endothermic, heat is absorbed by reactants. The value of heat of reaction is necessary to outside and In Endothermic, heat is absorbed by reactants. The value of heat of reaction is necessary to operate the chemical reactor.
operate the chemical reactor.
4. S
4. Safety Factorafety Factors:s:
This involve the confinement of any hazardous reactant and products as well as the control of reaction and This involve the confinement of any hazardous reactant and products as well as the control of reaction and process conditions.
process conditions.
Based on these factors the Reactor
Based on these factors the Reactor Types as follows;Types as follows; a. Mode of Operation - Batch or Continuous
a. Mode of Operation - Batch or Continuous b. Phases Types - Homog
b. Phases Types - Homogeneous or eneous or HeterogeneousHeterogeneous
c. Reactor Geometry - Flow Pattern & Process of contacting the phases. c. Reactor Geometry - Flow Pattern & Process of contacting the phases.
The five major
The five major classes of Reacclasses of Reactor;tor;
i. Batch i. Batch ii. Stirred ii. Stirred iii.Tubular iii.Tubular
iv.Packed Bed (Fixed) iv.Packed Bed (Fixed) v. Fludised Bed
v. Fludised Bed
Compounds like pigments, dye stuffs, pharmaceuticals and polymers are
Compounds like pigments, dye stuffs, pharmaceuticals and polymers are manufactured by Batch manufactured by Batch ProcessesProcesses.. The Latest Heat Exchangers are Direct or Contact Exchangers In addition to Double Pipe Exchanger, Shell The Latest Heat Exchangers are Direct or Contact Exchangers In addition to Double Pipe Exchanger, Shell & Tube Exchanger and Plated Frame Exchanger.
& Tube Exchanger and Plated Frame Exchanger.
Go to
Go to www.sdsenthil.comwww.sdsenthil.com
TOPI
TOPI
C 2:
C 2:
C
C
HLOR A
HLOR A
LKA
LKA
LI
LI
IN
IN
DUS
DUS
TRY
TRY
, INDUSTRIAL
, INDUSTRIAL
ACID, C
ACID, C
EMENT, G
EMENT, G
LASS &
LASS &
C
C
E
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RAMI
RAMI
C
C
S AND PULP &
S AND PULP &
PA
PA
PER
PER
Sodium Chloride Sodium Chloride
Sodium chloride is the basic raw material for many chemical compounds such as NaOH, Na
Sodium chloride is the basic raw material for many chemical compounds such as NaOH, Na22COCO33, Na, Na22SOSO44,, HCl, Na
HCl, Na22POPO44, , SodSodium ium ChlChloraorate, te, SoSodidium um ChlChloritorite e and and its its sosourcurce e of of mamany ny otother her proproduductcts s throthrougugh h itsits derivatives. Practically all the chlorine products in the world is manufactured by electrolysis of Sodium derivatives. Practically all the chlorine products in the world is manufactured by electrolysis of Sodium Chloride (NaCl), a common salt is manufactured in three different ways;
Chloride (NaCl), a common salt is manufactured in three different ways; Solar evaporation of sea water
Solar evaporation of sea water
1. 1.
Mining of rock salt Mining of rock salt
2. 2.
From well brines From well brines
3. 3.
1.
1. From saturated Brine by Multiple Effect Evaporator PrFrom saturated Brine by Multiple Effect Evaporator Processocess
Brine contains water 73.5%, sodium chloride 26.3%, calcium sulphate 0.12%, calcium chloride 0.003%, Brine contains water 73.5%, sodium chloride 26.3%, calcium sulphate 0.12%, calcium chloride 0.003%, magnesium chloride 0.007%.
magnesium chloride 0.007%. The flow sheet of pr
Process: Process:
The Brine is first aerated to remove most of the H The Brine is first aerated to remove most of the H22S.S.
1. 1.
Addition of chloride will remove H
Addition of chloride will remove H22S by displacement reaction.S by displacement reaction.
2. 2.
Brine is then pumped to settling tank where it is treated with caustic soda and soda ash to remove Brine is then pumped to settling tank where it is treated with caustic soda and soda ash to remove calcium, mag
calcium, magnesium and ferrnesium and ferr ic ions. Caustic soda and soda asic ions. Caustic soda and soda ash are h are blended in blended in the miser to the miser to be takenbe taken to settling tank.
to settling tank.
3. 3.
In the Multiple Effect Evaporator (MEE) water is removed and salt crystals are removed as slurry. In the Multiple Effect Evaporator (MEE) water is removed and salt crystals are removed as slurry.
4. 4.
The slurry is sent to washer, where the salt crystals are washed with fresh brine. The slurry is sent to washer, where the salt crystals are washed with fresh brine.
5. 5.
The washed slurry is filtered, mother liquor is return to the evaporators and salt crystals from the The washed slurry is filtered, mother liquor is return to the evaporators and salt crystals from the filter are dried and screened.
filter are dried and screened.
6. 6.
Salt thus produced from the typical brine is 99.8% purity or even greater. Salt thus produced from the typical brine is 99.8% purity or even greater.
7. 7.
The finest grade (some times made by grinding) is a flour salt, the next coarsest is table salt and The finest grade (some times made by grinding) is a flour salt, the next coarsest is table salt and finally the i
finally the i ndustndustrial salt.rial salt.
8. 8.
The Iodine salt has the following composition; The Iodine salt has the following composition;
Potassium
Potassium Iodide Iodide (KI) (KI) : : 0.01%0.01% Stabilizer Na
Stabilizer Na22COCO33 : 0.1%: 0.1% Sodium
Sodium Thio Thio Sulphate Sulphate : : 0.1%0.1%
2.
2. From SaturateFrom Saturated Brine by Open Pan Pd Brine by Open Pan Processrocess
Process: Process:
Salt in the form of hopper-like crystal (grainer salt) is made by causing the salt crystal to form on Salt in the form of hopper-like crystal (grainer salt) is made by causing the salt crystal to form on the surface of brine held in an open pan.
the surface of brine held in an open pan.
1. 1.
The grainer is a flat open pan 4.5 to 6.0 m width and 45 – 60 m long and about 60cm deep. Beneath The grainer is a flat open pan 4.5 to 6.0 m width and 45 – 60 m long and about 60cm deep. Beneath the pan steam coils system provided for reciprocating the flakes for salt removal.
the pan steam coils system provided for reciprocating the flakes for salt removal.
2. 2.
The saturated brine mixed with circulating brine from the grinder is treated to 120
The saturated brine mixed with circulating brine from the grinder is treated to 12000C at whichC at which temperature calcium sulphate is soluble and remove at that temperature.
temperature calcium sulphate is soluble and remove at that temperature.
3. 3.
The precipitated calcium sulphate is removed from gravellier which consist of bed of stones. The precipitated calcium sulphate is removed from gravellier which consist of bed of stones.
4. 4.
The purified brine is flash cooled to remove the remaining calcium sulphate. The purified brine is flash cooled to remove the remaining calcium sulphate.
5. 5.
The slurry is then pumped to the grinders where evaporation takes place at 96 The slurry is then pumped to the grinders where evaporation takes place at 9600C.C.
6. 6.
A wet salt crystals obtain from the grinder are centrifuged, dried and screened. A wet salt crystals obtain from the grinder are centrifuged, dried and screened.
7. 7.
When the incoming brine has been treated salt of 99.98% sodium chloride can be obtained. When the incoming brine has been treated salt of 99.98% sodium chloride can be obtained.
8. 8.
3.
3. From RFrom Rock Salt Miningock Salt Mining
About 35% of salt produced comes from mines of 8 different stages which are operated to produce rock About 35% of salt produced comes from mines of 8 different stages which are operated to produce rock salt. The salt deposits varying color from light reddish brown to half grey. The purity is 98.5%. After the salt. The salt deposits varying color from light reddish brown to half grey. The purity is 98.5%. After the rock is blasted loose they are crushed and then screened at the surface level. The remaining process is the rock is blasted loose they are crushed and then screened at the surface level. The remaining process is the series of grinding, screening to obtain the salft of crystal of various sizes.
series of grinding, screening to obtain the salft of crystal of various sizes.
4. From Sea Water by Solar Evaporation 4. From Sea Water by Solar Evaporation Annua
Annual l EvapEvaporatoration ion excexceedeeds s precprecipitipitatioation, n, the the ststatisatistictics s of of 125m125mm m of of rain rain cocorresprrespondonding ing to to 840m840mmm evaporation.
evaporation.
By-products of No
By-products of Normal Sarmal Saltlt (also called as value (also called as value added productsadded products)) Manufacture of sodium sulfates from salt and sulfuric acid Manufacture of sodium sulfates from salt and sulfuric acid
2NaCl + H
2NaCl + H22SOSO44--->> 2HCl + Na2HCl + Na22SOSO44 Na
Na22SOSO44 + 10H+ 10H22O -O ->> NaNa22SOSO44 + 2HCl+ 2HCl
Hargrea
Hargreaves-ves-Robinson Robinson ProProcesscess
Sulphur Di-oxide, air, steam are passed over specially prepared porous common salt. The reaction is as Sulphur Di-oxide, air, steam are passed over specially prepared porous common salt. The reaction is as follows;
follows; 2NaCl + SO
2NaCl + SO22++ 1/21/2OO22 + H+ H22O ---O --->> NaNa22SOSO44 + 2HCl+ 2HCl
Blea
Bleaching Powching Powderder Formulae: (CaOCl
Formulae: (CaOCl22).H).H22OO
Equation: Ca(OH)
Equation: Ca(OH)22 + Cl+ Cl22 --->> CaOClCaOCl22.H2O.H2O
The reaction is a low temperature reaction at 50
The reaction is a low temperature reaction at 50OOC in a counter current action by passing chorine throughC in a counter current action by passing chorine through a rotating steel cylinder with lifting blades which slower the solid through the path of the gas. When allow a rotating steel cylinder with lifting blades which slower the solid through the path of the gas. When allow to stand in air the bleaching powder absorbs CO
to stand in air the bleaching powder absorbs CO22 liberating HOCL (Hypochlorous acid). Other organic acidsliberating HOCL (Hypochlorous acid). Other organic acids also liberates same compound. The reactions are,
also liberates same compound. The reactions are, 2CaCl (OCl) + CO
2CaCl (OCl) + CO22 + H+ H22O ---O --->> CaClCaCl22 + CaCO+ CaCO33 + 3HClO+ 3HClO
2HClO
--2HClO -->> 2HCl + O2HCl + O22
After this formation bleaching powder liberates calcium chloride and oxygen. When dissolving in water the After this formation bleaching powder liberates calcium chloride and oxygen. When dissolving in water the reaction gives ionized calcium chloride and hypo chloride. The reaction is,
reaction gives ionized calcium chloride and hypo chloride. The reaction is,
2CaCl (OCl)
---2CaCl (OCl) --->> 2Ca2Ca2+2+ + 2Cl+ 2Cl-- + 2OCl+ 2OCl
--The OCl
The OCl-- ion decomposes by liberating oxygen. However the acidity of the product is determined by the %ion decomposes by liberating oxygen. However the acidity of the product is determined by the % of chlorine in the compound, which is defined as weight of chlorine that will exerts the same action as the of chlorine in the compound, which is defined as weight of chlorine that will exerts the same action as the chlorine
chlorine compcompound what we choose.ound what we choose.
In the case of Bleaching powder, average chlorine is the same as the % of chlorine in the compound. In In the case of Bleaching powder, average chlorine is the same as the % of chlorine in the compound. In the case of ca
compound. These values are obtained as soon as the freshly prepared compound from the process is finally compound. These values are obtained as soon as the freshly prepared compound from the process is finally taken.
taken.
Sulfuric Acid Sulfuric Acid
Lead Chamber Process Lead Chamber Process Contact Process
Contact Process
Lead C
Lead Chamber Prohamber Processcess
Essentially this process consists of oxidizing a mixture of sulfur dioxide and water to sulfuric acid using Essentially this process consists of oxidizing a mixture of sulfur dioxide and water to sulfuric acid using nitric oxide as an oxygen carrier. The reaction is,
nitric oxide as an oxygen carrier. The reaction is, H
H22O + SOO + SO22 + NO+ NO22 --->> HH22SOSO44 + NO+ NO
This Nitric Oxide
This Nitric Oxide (NO) com(NO) combines with oxygen to bines with oxygen to from nitrogen dioxide which is from nitrogen dioxide which is used again in used again in the processthe process.. The formation of NO
The formation of NO22 is given by,is given by,
2NO + O
2NO + O22 --->> 2NO2NO22
The process consists of thr
The process consists of three stages.ee stages.
The first stage takes place in the Glover tower. This tower is packed with acid resistant bricks over which a The first stage takes place in the Glover tower. This tower is packed with acid resistant bricks over which a co
consnstant stream of tant stream of sulfsulfuric acid made by uric acid made by mixmixing ing the the outpoutput ut of of lead chamlead chambers (65% bers (65% AciAcid) and d) and thethe Gay-Lusaac Tower (70% Acid) combines with oxides of Nitrogen. Then the hot mixture of SO
Gay-Lusaac Tower (70% Acid) combines with oxides of Nitrogen. Then the hot mixture of SO22 and Air fromand Air from the furnace is fed into the base of Glover Tower and comes into intimate contact with the descending acid the furnace is fed into the base of Glover Tower and comes into intimate contact with the descending acid of low concentratio
of low concentration. Acid results the n. Acid results the gasgases from the es from the burners are burners are coocooled from 500led from 500 00C to about 90C to about 90 00C andC and the oxides of nitrogen are extracted from the acid and carried over to the other chambers. In addition the the oxides of nitrogen are extracted from the acid and carried over to the other chambers. In addition the acid undergoes the concentration of 70% by the time it reaches the base of the Glover Tower. Some of the acid undergoes the concentration of 70% by the time it reaches the base of the Glover Tower. Some of the sp
spent ent acacid id aftafter er cocoming from ming from the the GloveGlover r ToTower wer is is alsalso o sosold ld cocommmmerciercially ally for for proprocecessssed ed whewhere re thatthat concentrated acid is required.
concentrated acid is required.
The second stage takes place in the lead chamber from which the process derives its name. Water is The second stage takes place in the lead chamber from which the process derives its name. Water is spread from the roof on to the mixture of gases are SO
spread from the roof on to the mixture of gases are SO22 and NOand NO22. They slowly react together under. They slowly react together under carefully controlled conditions of humidity and temperatures producing 65% H
carefully controlled conditions of humidity and temperatures producing 65% H22SOSO44 which is collected onwhich is collected on the shop floor. Lead is used in the material of construction as it is not corroded by acid. The humidity is the shop floor. Lead is used in the material of construction as it is not corroded by acid. The humidity is co
controllntrolled by ed by the variatiothe variations in ns in the dry the dry bulb tembulb temperaperature ture and wet bulb and wet bulb temtemperaperature obseture observed in rved in thethe psychometric chart available in the process plant.
psychometric chart available in the process plant.
The third stage takes place in the Gay-Lusaac Tower which is designed to recover as much as possible of The third stage takes place in the Gay-Lusaac Tower which is designed to recover as much as possible of the
concentrated acid. concentrated acid.
The main purpose of this Tower is to minimize the problem of escape of NO
The main purpose of this Tower is to minimize the problem of escape of NO22 to atmosphere. But in theto atmosphere. But in the later stages the recovery was more important as the efficiency was high and cost very cheap. A small loss later stages the recovery was more important as the efficiency was high and cost very cheap. A small loss of oxide of nitrogen is inevitable. However it is made good by introducing additional nitric oxide formed by of oxide of nitrogen is inevitable. However it is made good by introducing additional nitric oxide formed by catalytic oxidation of ammonia.
catalytic oxidation of ammonia.
This chamber process produces cheap acid of doubtful purity with concentration of 65-80% at maximum. This chamber process produces cheap acid of doubtful purity with concentration of 65-80% at maximum. This was used for manufact
This was used for manufacture ure of fertilizers, of fertilizers, but where but where more concemore concentrated acids are required ntrated acids are required the contactthe contact process is followed.
process is followed.
Contact
Contact PrProcessocess
Today contact proces
Today contact process is the s is the most widely used process for the manufacturmost widely used process for the manufactur e of He of H22SOSO44 throughout the world.throughout the world. The raw materials used to make sulfuric acid are elemental sulfur, H
The raw materials used to make sulfuric acid are elemental sulfur, H22SOSO44 and Hand H22S.S.
Till 1970, Ion Pyrites and related compounds were the predominant raw materials. The large amount of Till 1970, Ion Pyrites and related compounds were the predominant raw materials. The large amount of sulfuric acid also produced as a by-product of non-ferrous metal smelting. i.e. roasting sulfide ores of sulfuric acid also produced as a by-product of non-ferrous metal smelting. i.e. roasting sulfide ores of copp
copper, lead, molybdenum, nickel, zer, lead, molybdenum, nickel, zinc and some others. The process is dividing to tinc and some others. The process is dividing to t he followinhe following steps;g steps; Generation of sulfur dioxide gas
Generation of sulfur dioxide gas
1. 1. Catalytic Oxidation of SO Catalytic Oxidation of SO22 to SOto SO33 2. 2. Absorbing SO
Absorbing SO33 to form Hto form H22SOSO44
3. 3.
The reactions are as follows; The reactions are as follows;
S + O S + O22 --->> SOSO22 1. 1. SO SO22 + ½ O+ ½ O22 --->> SOSO33 ^H = -98KJ^H = -98KJ 2. 2. SO
SO33 + H+ H22O O --->> HH22SOSO44 ^H = -132.5KJ (Highly Exothermic Reactions)^H = -132.5KJ (Highly Exothermic Reactions)
3. 3.
P
Properties of Sroperties of Sulfuric Acidulfuric Acid
When a dilute solution of sulfuric acid is distilled a constant boiling point mixture is obtained contains When a dilute solution of sulfuric acid is distilled a constant boiling point mixture is obtained contains 98
98..3% 3% of of HH22SOSO44. T. This his mmixixtuture re boboils ils at at 333388 00C C and has and has a a dedensnsity ity of of 1.1.84g84gm.m.cmcm-3-3 is is the the nornormamall conc
concentration acid availabentration acid available in le in the laboratory. If the little Sthe laboratory. If the little S OO33 is dissis dissolved in that olved in that acid 100% takes acid isacid 100% takes acid is obtained and an oily liquid which freezes to crystals of white color at 10
obtained and an oily liquid which freezes to crystals of white color at 10 00C. Concentrated sulfuric acid isC. Concentrated sulfuric acid is highly corrosive and should always be handle with care. It causes severe bores when contacted with the highly corrosive and should always be handle with care. It causes severe bores when contacted with the skin.
skin.
Reactions of Sulfuric Acid Reactions of Sulfuric Acid
