Friends, here I have attached quite tough questions which is asked in one reputed process industry. Check out the answers for this questions you will get a great idea about basic chemical engineering. try out this!
Any idea on recombinant protein expression?
Are carbon steel storage tanks appropriate for NaOH solutions?
Are fin tubes necessary for steam heating a liquid?
Cetane no. and sulphur required in diesel fuel for euro-IV
Do you have recombinant protein expression experience? Explain?
Explain the Deacon reaction?
Explain various protein purification techniques?
For a centrifugal pump if the pump is running and we close the discharge valve what is the effect
How are plate heat exchangers used in an ammonia refrigeration system?
how can we derive power factor equation p=vi cos phi? derivation?
how can we measure entropy?
how FOULING effectd the heat transfer rate
How much experience you are having in commercial software for protein design?
how much maximum power can be generated by 320v, 10kg-cm synchronus motor if shaft is roteted mechanically at 50 to 60 rpm?
how to calculat suction head in centrifugal pump?
How to calculate the release flowrates from pressurized gas systems?
How to calculate the sonic velocity of a gas stream?
How to determine the particle size distribution for a given bulk solid?
How to estimate the efficiency of a pump?
Is it possible to compare the resistance to chloride attack of several materials of construction?
Is petroleum a mixture of hydrocarbon?
Name of the fraction at which benzene xylene and toulene is obtained during coal tar distillation
Thyristor related applications
What are some good estimates for heat transfer coefficients for coils in tanks?
What are the affinity laws associated with dynamics pumps?
What are the effects of oils on the properties of Polyolefins?
what are the precautions u are taking while starting HT motors?
What are the steps involved in w.ine making?
What can cause bulk solids to stop flowing from a bin?
What compounds are responsible for the odours that come from wastewater treatment plants?
What does the catalystic converter on an automobile do?
What is a good estimate for the absolute roughness for epoxy lined carbon steel pipe?
What is are the main terms in Unit Operations? and what is its charecteristics?
What is difference between Overall heat transfer coeficient & individual heat transfer coefficient
what is load and what are the types of load?
what is meaning of pid how it is useing controlers
What is Pinch Technology?
what is the apt definitions for apparent power ,active power and reactive power?and explanation about different types of lamps?
what is the differance between Horizental and vertical heat exchanger?
what is the discharge pressure formula, for calculating discharge pressure?
What is the ignition temp. of Alluminium,Coper & Iron.
What is the ignititon temprecher of Diesel,Petrol & Carosion oil.
What is the Import Procurement Cycle ? and what are the customization steps in SAP ?
what is the meaning of flaring
What is the most common cause of solid size segregation in bulk solid systems?
what is the purpose of capacitor? and capacitor load means what? how does it connect?
What is the reason for removing silicon from aluminum?
What is the speed of a rotary drier
What is the symbol of sodium ?
What is the various utilities of the process plant?
What is unit operation?
What regulates, or gives a substance the viscosity it has?
What steps can be taken to avoid stress corrosion cracking (SCC) in steel vessels used for storing anhydrous ammonia?
Which is more effective , a single extraction with a large volume of solvent or several small volume extractions? Explain.
Which reformer efficiencywise best?
Which thing is responsible for making petroleum?
Why is post-weld heat treatment sometimes necessary for welded vessels?
Why is steam added into the cracker in thermal cracking
Most theories concerning the origin of petroleum postulate and vegetable origin with a close relationship to coal. Theory holds that any organic matter may be converted into petroleum under suitable conditions. There is also general agreement that petroleum was formed from organic matter near shore and in marine deposit deficient in oxygen and associated with minerals converted by time and pressure into limestone, dolomites, sand stones and similar rocks. The concentration of organic matter in original deposits may not have been high but petroleum gas and liquids have migrate and gather in places favoring in retention, e.g., sealed of porous sand stones over long period of times, carbohydrates and proteins have probably destroyed by bacterial action leaving the fatty oils which more refractory to bacterial or chemical destruction.
EXPLORATION
At one time drilling for petroleum was a hit or fewer affairs and only one out of hundred wildcat wells struck oil. Geophysical and seismic work has become highly refined and when combined with high-speed computers to evaluate the vast amount of data used to locate sites. By 1962 one out of 9 wells drilled produced oil, gas or both. Today’s success rate is even better. Geologist recognized at an early date that petroleum accumulates in pools caught in the anti clinical folds of sedimentary rocks.
Seismic analysis can determine the presence of domes and deposits at a considerable depth below the surface. The top of the arch of an anticline or dome is compressed and has greater density than the surrounding rocks. Creating small seismic waves and measuring the reflected waves at intervals in space and time makes possible accurate gravimetric the finding of new field is a most serious and expensive undertaking. At scientifically selected sites, wells have been drilled deeper than 6500 m to meet gas or oil.
CONSTITUENTS OF PETROLEUM
Crude petroleum is made up of thousands of different chemical substances including gases, liquids andsolids and ranging from methane to asphalt. Most constituents are hydrocarbons but there are significant amounts of compounds containing nitrogen (0-0.5%), sulfur ( 0-6% ) and oxygen ( 0-3.5% ).
ALIPHATICS OR OPEN CHAIN HYDROCARBONS
n-paraffin series or alkanes CnH2n+2
This series comprises a larger fraction of most crude than any other. Mo0st straight run gasoline is predominantly n-paraffins. These materials have poor anti-knock properties.
(E.g., n-heptane knocks badly)
iso-paraffin series or iso-alkanes CnH2n+2
These branched chain materials perform better in internal combustion engines than n-paraffins and hence considered more desirable. They may be formed by catalytic reforming alkylation, polymerization, and isomerization only small amounts exist in crudes.
(E.g., 2 and 3 methyl pentane)
Olefin or alkene series CnH2n
This series is actually absent in crudes but refining processes such as cracking (making smaller molecules from larger ones) produce them these relatively unstable molecules improve the anti-knock properties of gasoline, although not as effective on storage they polymerize and oxidize this tendency to react, however, makes them useful for forming compounds (petro-chemicals) . (E.g., ethene, propene, butene)
PROCESS OF REFINING
Refining is a low cost operation compared to most chemical processing. Refining involves two major branches.
They are:
üSeparation process
üConversion process
Particularly in the field of conversion, there are literally hundreds of processes. Among them they are alkylation, polymerization, and isomerization, reforming, hydrogenation, de-hydrogenation.
Refineries where originally batch units with cylindrical under fired shell stills operated at topping units pumping oil continually through heaters known as pipe or tube stills and separating the constituents in continues fractionating columns. They separate many fractions between gas and asphalt. Primary separation followed by various conversion processes designed to optimize yields of more profitable and salable products the maximum yield is gasoline.
ENERGY CHANGES
For many years, energy expense for refining has been the most important manipulatable cost. Conservation of heat has been the object of concentrated study. Since the sharp increase the cost of energy, this study has been intensified. The great needs of the growing petroleum industry led to the careful study of fluid flow, heat transfer, and the properties of petroleum fractions.
SEPARATION PROCESSES
The unit operations used in the petroleum refining is the simple, usual once, but the interconnections and interaction may be complex. Most major units are commonly referred to as stills. Crude still consists of heat exchangers, a furnace, a fractionating tower, steam strippers, condensers, coolers and auxiliaries. These are usually working tanks for temporary storage tanks at the unit. For the refinery as the whole boiler house and usually electrical generating system are added. Control room with instruments to measure, record, and control thus keeping track of material which permits heat and material balances.
The following unit operations are extensively used in separating section
FLUID FLOW
The fluid flow is an operation that must not permit any unexpected failure because fire and explosion may ensure.
HEAT TRANSFER
Heat transfer coefficients change daily as fouling occurs. Cooling towers become less effective with time.
DISTILLATION
When side streams withdrawn, they contain undesirable light volatiles, which are usually removed in small auxiliary steam stripping. Tower contacting material, at one time all packing or bubble caps, now consist of variety of tower packing and special trays design to reduce pressure drop while increasing vapor - liquid contact.
ABSORPTION
It is generally used to separate high-boilers from wet gases. Gases, which are expelled from gas storage tanks as a result of solar, heating, are also sent to absorption plant for recovery. Steam stripping is generally used to recover the light hydrocarbons and restore the absorption capacity of the gas oil.
ADSORPTION
It is used for recovery of heavy metals from gases. Adsorbents such as activated charcoal and molecular sieves are used. Molecular sieves can select the materials recovered by molecular shapes as well as molecular weights; this can be very useful. Energy can be saved by using a pressure swing absorption process wherein the material is released from the adsorbent by changing the system pressure.
FILTRATION
It is used to remove wax precipitated from wax-containing distillates. If the cold cake is allowed to warm slowly, the low melting oils drain (Sweat out)from the cake and further purify it.
CRYSTALISATION
Before filtration, waxes must be crystallized to suitably sized crystals by cooling and stirring. Waxes undesirable in lubes are removed and become the microcrystalline waxes of commerce. For most purposes this operation is both slow and expensive.
EXTRACTION
It is removal of a component by selectively dissolving it in a liquid. This procedure is very important in preparing high quality lube oil. Then low viscosity index waxes; color bodies and sulfur compounds are removed in this way.
CONVERSION PROCESSES
The following are the examples of the more important basic reactions, which are
CRACKING or PYROLYSIS
The breaking down of large hydrocarbon molecules into smaller molecules by heat or catalytic reactions. Zeolites catalysts are common. Other types are also used.
POLYMERIZATION
The linking of similar molecules, the joining together of light olefins
ALKYLATION
The union of an olefin with an aromatic or paraffinic hydrocarbon.
Unsaturated +Iso-saturated à saturated branched chain e.g., catalytic alkylation
HYDROGENATION
The addition of hydrogen to an olefin.
HYDROCRACKING
C 7H15 C15 H30.C7 H 30+H2O ==> C7H16+C7H16+C7H32
ISOMERIZATION
Alteration of the arrangement of the action in molecule without changing the number of atoms.
REFORMING or AROMATIZATION
The conversion of naphtha to obtain the products of higher octane number similar to cracking but more volatile charge stocks is used. Catalysts usually contain rhenium, platinum or chromium.
Distillation of the crude oil yields number of products of varying boiling ranges. These fractions are processed to suitable utilities.
NATURAL GAS
Contains mainly varying proportions of methane. It may be accompanied by other dry gas fractions like ethane and propane.
GASOLINE
Following the gas, it is the next fraction. It is a volatile fraction and is known as Motor Spirit. The boiling points ranges from 37 0c to 180 0c. Gasoline is a finished product, while raw fractions are known as naphtha.
There are 40 types of gasoline products produced by refineries. Automobile industry and the rest exclusively consume 90% of them by aviation industry.
ADDITIVES
Different types of additives are blended into gasoline to give uninterrupted and smooth service:
üAnti-icings &detergents
üCorrosion and oxidation inhibitors
üCombustion aids
üAnti-knocks
üColors and dyes
AVIATION TURBINE FUELS
Modern jet engines use fuel similar to the kerosene. It is a most flexible fuel in its boiling ranges.
AVIATION GASOLINE
Gasoline containing all the additives is generally meant for motor gasoline.
NAPHTHA
These fractions are highly volatile and fall in the boiling range of motor spirit. These are mostly used as travel.
KEROSENE
Kerosene is the general name applied to the group of refined petroleum fractions. Employed as fuel and illuminant. All these fractions have approximate boiling range 150 0c to 250 0c . These are uniform low distillates, low in viscosity, with a good degree of refinement to be fairly stable, light in color and free from smoky, ill smelling substances.
DIESEL FUEL
Diesel oil is the fraction in the boiling range of 250 0c to –320 0c and fall under gas oil fractions. They are basically divided into two classes
üLow speed diesel
üHigh-speed diesel
LUBE OIL
The principle source of lubricating oil is the fraction that is left after lighter components namely gasoline, kerosene, diesel oil, during crude distillation. Generally lubes have a boiling point above 350 0c and these are obtained as main products from vacuum distillation units.
TRANSFORMER OIL
These oils are used in electrical industry mainly for insulating and cooling purpose additionally these oils protect the equipment form moisture compared to vegetable or coal distillate oils, petroleum oils, are found to be more suitable because of high viscosity, thermal stability and hydrophobic nature.
BITUMEN
Bitumen is the residual product obtained from crude distillation unit. It is essentially solid at room temperature and has got very high viscosity.
HISTORY OF PETROLEUM
ORIGIN
Most theories concerning the origin of petroleum postulate and vegetable origin with a close relationship to coal. Theory holds that any organic matter may be converted into petroleum under suitable conditions. There is also general agreement that petroleum was formed from organic matter near shore and in marine deposit deficient in oxygen and associated with minerals converted by time and pressure into limestone, dolomites, sand stones and similar rocks. The concentration of organic matter in original deposits may not have been high but petroleum gas and liquids have migrate and gather in places favoring in retention, e.g., sealed of porous sand stones over long period of times, carbohydrates and proteins have probably destroyed by bacterial action leaving the fatty oils which more refractory to bacterial or chemical destruction.
EXPLORATION
At one time drilling for petroleum was a hit or fewer affairs and only one out of hundred wildcat wells struck oil. Geophysical and seismic work has become highly refined and when combined with high-speed computers to evaluate the vast amount of data used to locate sites. By 1962 one out of 9 wells drilled produced oil, gas or both. Today’s success rate is even better. Geologist recognized at an early date that petroleum accumulates in pools caught in the anti clinical folds of sedimentary rocks.
Seismic analysis can determine the presence of domes and deposits at a considerable depth below the surface. The top of the arch of an anticline or dome is compressed and has greater density than the surrounding rocks. Creating small seismic waves and measuring the reflected waves at intervals in space and time makes possible accurate gravimetric the finding of new field is a most serious and expensive undertaking. At scientifically selected sites, wells have been drilled deeper than 6500 m to meet gas or oil.
CONSTITUENTS OF PETROLEUM
Crude petroleum is made up of thousands of different chemical substances including gases, liquids andsolids and ranging from methane to asphalt. Most constituents are hydrocarbons but there are significant amounts of compounds containing nitrogen (0-0.5%), sulfur ( 0-6% ) and oxygen ( 0-3.5% ).
ALIPHATICS OR OPEN CHAIN HYDROCARBONS
n-paraffin series or alkanes CnH2n+2
This series comprises a larger fraction of most crude than any other. Mo0st straight run gasoline is predominantly n-paraffins. These materials have poor anti-knock properties.
(E.g., n-heptane knocks badly)
iso-paraffin series or iso-alkanes CnH2n+2
These branched chain materials perform better in internal combustion engines than n-paraffins and hence considered more desirable. They may be formed by catalytic reforming alkylation, polymerization, and isomerization only small amounts exist in crudes.
(E.g., 2 and 3 methyl pentane)
Olefin or alkene series CnH2n
This series is actually absent in crudes but refining processes such as cracking (making smaller molecules from larger ones) produce them these relatively unstable molecules improve the anti-knock properties of gasoline, although not as effective on storage they polymerize and oxidize this tendency to react, however, makes them useful for forming compounds (petro-chemicals) . (E.g., ethene, propene, butene)
PROCESS OF REFINING
Refining is a low cost operation compared to most chemical processing. Refining involves two major branches.
They are:
üSeparation process
üConversion process
Particularly in the field of conversion, there are literally hundreds of processes. Among them they are alkylation, polymerization, and isomerization, reforming, hydrogenation, de-hydrogenation.
Refineries where originally batch units with cylindrical under fired shell stills operated at topping units pumping oil continually through heaters known as pipe or tube stills and separating the constituents in continues fractionating columns. They separate many fractions between gas and asphalt. Primary separation followed by various conversion processes designed to optimize yields of more profitable and salable products the maximum yield is gasoline.
ENERGY CHANGES
For many years, energy expense for refining has been the most important manipulatable cost. Conservation of heat has been the object of concentrated study. Since the sharp increase the cost of energy, this study has been intensified. The great needs of the growing petroleum industry led to the careful study of fluid flow, heat transfer, and the properties of petroleum fractions.
SEPARATION PROCESSES
The unit operations used in the petroleum refining is the simple, usual once, but the interconnections and interaction may be complex. Most major units are commonly referred to as stills. Crude still consists of heat exchangers, a furnace, a fractionating tower, steam strippers, condensers, coolers and auxiliaries. These are usually working tanks for temporary storage tanks at the unit. For the refinery as the whole boiler house and usually electrical generating system are added. Control room with instruments to measure, record, and control thus keeping track of material which permits heat and material balances.
The following unit operations are extensively used in separating section
FLUID FLOW
The fluid flow is an operation that must not permit any unexpected failure because fire and explosion may ensure.
HEAT TRANSFER
Heat transfer coefficients change daily as fouling occurs. Cooling towers become less effective with time.
DISTILLATION
When side streams withdrawn, they contain undesirable light volatiles, which are usually removed in small auxiliary steam stripping. Tower contacting material, at one time all packing or bubble caps, now consist of variety of tower packing and special trays design to reduce pressure drop while increasing vapor - liquid contact.
ABSORPTION
It is generally used to separate high-boilers from wet gases. Gases, which are expelled from gas storage tanks as a result of solar, heating, are also sent to absorption plant for recovery. Steam stripping is generally used to recover the light hydrocarbons and restore the absorption capacity of the gas oil.
ADSORPTION
It is used for recovery of heavy metals from gases. Adsorbents such as activated charcoal and molecular sieves are used. Molecular sieves can select the materials recovered by molecular shapes as well as molecular weights; this can be very useful. Energy can be saved by using a pressure swing absorption process wherein the material is released from the adsorbent by changing the system pressure.
FILTRATION
It is used to remove wax precipitated from wax-containing distillates. If the cold cake is allowed to warm slowly, the low melting oils drain (Sweat out)from the cake and further purify it.
CRYSTALISATION
Before filtration, waxes must be crystallized to suitably sized crystals by cooling and stirring. Waxes undesirable in lubes are removed and become the microcrystalline waxes of commerce. For most purposes this operation is both slow and expensive.
EXTRACTION
It is removal of a component by selectively dissolving it in a liquid. This procedure is very important in preparing high quality lube oil. Then low viscosity index waxes; color bodies and sulfur compounds are removed in this way.
CONVERSION PROCESSES
The following are the examples of the more important basic reactions, which are
CRACKING or PYROLYSIS
The breaking down of large hydrocarbon molecules into smaller molecules by heat or catalytic reactions. Zeolites catalysts are common. Other types are also used.
POLYMERIZATION
The linking of similar molecules, the joining together of light olefins
ALKYLATION
The union of an olefin with an aromatic or paraffinic hydrocarbon.
Unsaturated +Iso-saturated à saturated branched chain e.g., catalytic alkylation
HYDROGENATION
The addition of hydrogen to an olefin.
HYDROCRACKING
C 7H15 C15 H30.C7 H 30+H2O ==> C7H16+C7H16+C7H32
ISOMERIZATION
Alteration of the arrangement of the action in molecule without changing the number of atoms.
REFORMING or AROMATIZATION
The conversion of naphtha to obtain the products of higher octane number similar to cracking but more volatile charge stocks is used. Catalysts usually contain rhenium, platinum or chromium.
Distillation of the crude oil yields number of products of varying boiling ranges. These fractions are processed to suitable utilities.
NATURAL GAS
Contains mainly varying proportions of methane. It may be accompanied by other dry gas fractions like ethane and propane.
GASOLINE
Following the gas, it is the next fraction. It is a volatile fraction and is known as Motor Spirit. The boiling points ranges from 37 0c to 180 0c. Gasoline is a finished product, while raw fractions are known as naphtha.
There are 40 types of gasoline products produced by refineries. Automobile industry and the rest exclusively consume 90% of them by aviation industry.
ADDITIVES
Different types of additives are blended into gasoline to give uninterrupted and smooth service:
üAnti-icings &detergents
üCorrosion and oxidation inhibitors
üCombustion aids
üAnti-knocks
üColors and dyes
AVIATION TURBINE FUELS
Modern jet engines use fuel similar to the kerosene. It is a most flexible fuel in its boiling ranges.
AVIATION GASOLINE
Gasoline containing all the additives is generally meant for motor gasoline.
NAPHTHA
These fractions are highly volatile and fall in the boiling range of motor spirit. These are mostly used as travel.
KEROSENE
Kerosene is the general name applied to the group of refined petroleum fractions. Employed as fuel and illuminant. All these fractions have approximate boiling range 150 0c to 250 0c . These are uniform low distillates, low in viscosity, with a good degree of refinement to be fairly stable, light in color and free from smoky, ill smelling substances.
DIESEL FUEL
Diesel oil is the fraction in the boiling range of 250 0c to –320 0c and fall under gas oil fractions. They are basically divided into two classes
üLow speed diesel
üHigh-speed diesel
LUBE OIL
The principle source of lubricating oil is the fraction that is left after lighter components namely gasoline, kerosene, diesel oil, during crude distillation. Generally lubes have a boiling point above 350 0c and these are obtained as main products from vacuum distillation units.
TRANSFORMER OIL
These oils are used in electrical industry mainly for insulating and cooling purpose additionally these oils protect the equipment form moisture compared to vegetable or coal distillate oils, petroleum oils, are found to be more suitable because of high viscosity, thermal stability and hydrophobic nature.
BITUMEN
Bitumen is the residual product obtained from crude distillation unit. It is essentially solid at room temperature and has got very high viscosity.
