ChECal Flashcards
A unit operation in which a soluble component is removed from an inert solid by a solvent which preferentially dissolves the soluble matter is known as
Leaching
The unit operation by which soluble components of a liquid mixture are dissolved in a liquid immiscible with the insoluble component is
Solvent Extraction
Tea percolation employs
Leaching
Leaching of sugar from sugar beets is done using
Hot water
In a counter-current extractor, as the axial mixing increases, the extraction efficiency
Decreases
Bollman extractor is used for ____
extraction of oil from oilseed
Radioactive nuclear waste is treated in
Pulsed column extractor
Acetic acid will be most economically separated from a dilute solution of acetic acid in water by
Solvent extraction
Liquid-liquid extraction is based on the differences in ___
solubility
Heats sensitive materials with very high latent heat of vaporization may be economically separated using ___
liquid extraction
Which method is more efficient, a single large washing or repeated small washing?
repeated small washing
Which of the following equipment is not used in liquid-liquid extraction?
Pachuka tank
Heat sensitive materials with very high latent heat of vaporisation may be economically separated using
Liquid extraction
The solvent used in liquid extraction should not have high latent heat of vaporization, because
Its recovery cost by distillation may be prohibitatively high
Solvent extraction is the terminology applied to the liquid-liquid extraction, which is preferred for the separation of the components of liquids, when
extracting solvent is cheaply & abundantly available.
In a counter-current liquid extractor
only one of the liquids may be pumped at any desired rate.
A coalescer in a mixer-settler liquid-liquid extraction column
a. comprises of thin bed of substances of extended surface
having high porosity.
b. helps in increasing the bubble size entering the settler.
c. helps in increasing the settling rate of the bubbles.
d. all of these
all of these
Antibiotics are best handled in a
a. Podbielniak extractor
b. rotating disc contactor
c. sieve tray contractor
d. pulsed column extractor
Podbielniak extractor
Which of the following solutions will follow Raoult’s law most
closely?
a. A solution of benzene, toluene and oxylene
b. 35% solution of camphor in water
c. 35% solution of NH3 in water
d. A solution of polar organic compounds (not of homologs of a
series).
a. A solution of benzene, toluene and oxylene
Boiling point diagram is
a. not affected by pressure.
b. affected by pressure.
c. a plot of temperature vs. liquid composition.
d. a plot of temperature vs. vapor composition.
b. affected by pressure.
- The ease of difficulty of separating components by distillation is
determined by the
a. relative volatility
b. viscosity
c. mole fraction
d. weight fraction of the components
a. relative volatility
Strictly speaking, the relative volatility of most ideal binary
solution is
a. not affected by temperature
b. greatly affected by temperature
c. slightly affected by temperature
d. greatly affected by pressure
c. slightly affected by temperature
When the relative volatility of two miscible components is close to 1.00, the components can be separated by _____
c. extractive distillation
Distillation used for multicomponent systems like crude refining
Flash Distillation
The physical separation of components in a miscible mixture by simultaneous evaporation and condensation is
a. absorption
b. drying
c. extraction
d. distillation
d. distillation
In a batch distillation, the boiling point of the distillate product compared to the residue is
a. the same
b. higher
c. lower
d. half
c. lower
The temperature ____ as we go up the distillation column
decreases
The section below the feed plate is called
Stripping section
Operating line that always lies below the equilibrium curve
stripping section
In a packed column, channeling is prevented by which of the following equipment?
Liquid distributor
Increasing the operating pressure of a distilling column
a. does not make a difference in components separation
b. makes separation difficult
c. sharpens separation
d. requires less heat in the feed heater
b. makes separation difficult
One mole feed of a binary mixture of a given composition is flash vaporized at a fixed P and T. If Raoult’s law is obeyed, then changing the feed composition would effect
a. the product composition but not the fraction vaporized.
b. the product composition as well as the fraction vaporized.
c. the fraction vaporized but not the product composition.
d. neither the product composition nor the fraction vaporized.
C. The fraction vaporised but not the product composition
Steam distillation is used to
a. reduce the number of plates.
b. avoid thermal decomposition of a component.
c. increase the efficiency of separation.
d. increase the total pressure of distillation.
b. avoid thermal decomposition of a component.
The amount of steam required per unit quantity of distillate in case of steam distillation will be reduced by
a. raising the temperature
b. lowering the total pressure
c. both (a) and (b)
d. neither (a) nor (b)
c. both (a) and (b)
In distillation, the cooled liquid stream returned to the column to a cool plate or stage is called
a. reboil
b. reflux
c. feed
d. bottoms
b. reflux
In a distilling column, the highest pressure will be at
a. the top
b. the bottom
c. the feed plate
d. between the feed plate and the top
b. the bottom
A heat transfer equipment to convert vapor to liquid is a/an
a. evaporator
b. reboiler
c.condenser
d. still
c.condenser
A reboiler provides heat to the
a. top
b. the feed
c. the intermediate reflux
d. the bottom of a distilling column
d. the bottom of a distilling column
The temperature in distilling column, from bottom to top
a. increases
b. maximum
c. decreases
d. between minimum & maximum
a. decreases
The theoretical minimum reflux ratio in distillation column is
attained if the column has
a. 1 plate
b. 10 plates
c. 100 plates
d. infinite number of plates
d. infinite number of plates
If x co-ordinate of intersection point of feed line and rectifying sections operating line on equilibrium curve is same as the mole fraction of more volatile components in the feed, then the quality of feed is
a. subcooled liquid
b. saturated vapor
c. saturated liquid
d. superheated vapor
c. saturated liquid
As the reflux ratio decreases, the
a. separation becomes more efficient.
b. number of plates increases.
c. column diameter increases.
d. none of these.
number of plates increases.
In a distillation column, with increase in the reflux ratio, the heat
removed in the cooler _____
increases
Fenske’s equation for determining the minimum number of theoretical stages in distillation column holds good, when the ____
relative volatility is reasonably constant.
Inside the distillation column, the ____
a. driving force for the vapor flow is the pressure drop.
b. liquids are not always at their bubble points.
c. pressure increases gradually from bottom to the top of the column.
d. none of these
driving force for the vapor flow is the pressure drop.
On moving the feed line (q-line) from saturated liquid feed (vertical position) to saturated vapor feed (horizontal feed), if the slope of both the operating lines are to be increased, then it will result in ___
increased reflux ratio
In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of _____
area between operating line and 45° diagonal x-y diagram
Overall efficiency of the distillation column is equal to ____
the ratio of number of ideal plates to actual plates
Design calculation for multiple component distillation is done by ____
tray to tray calculations
Pick out the wrong statement:
a. Reboiler is not used in open steam distillation.
b. The separation of solutes of different molecular sizes in a liquid solution by use of a suitable membrane is called dialysis.
c. Freeze drying is used for the drying of fish.
d. Fenske-Underwood equation is used for calculating theoretical number of plates in a distillation column at normal operating reflux
condition.
Fenske-Underwood equation is used for calculating theoretical number of plates in a distillation column at normal operating reflux
condition.
In extractive distillation, solvent is used to ____
added to alter the relative volatility of the mixture.
In case of __________ distillation, a solvent is added to alter the relative volatility of the mixture to be separated.
Extractive
Solvent used in extractive distillation forms ____
forms a low boiling azeotrope.
Pick out the wrong statement.
a. Critical moisture content is not a property of the material itself.
b. A sharp increase in pressure drop gives an indication of the flooding in a distillation column.
c. Separation of components is not possible in liquid extraction, if selectivity is unity.
d. Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum.
Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum.
The equilibrium liquid composition compared to the vapor composition in case of azeotropic mixture is
same
(SAME AND ISASAGOT HINDI EQUAL)
Pick out the wrong statement.
a. The mole fraction of solute is directly proportional to the molality of a ‘dilute’ solution.
b. For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both components is nonlinear in the case of steady state unimolal unidirectional diffusion.
c. Azeotropes obey Raoult’s law at all temperature.
d. The relative volatility of a binary mixture at the azeotropic composition is 1.
Azeotropes obey Raoult’s law at all temperature.
Azeotropic distillation is employed to separate ____.
constant boiling mixture
Pick out the system with minimum boiling azeotrope at 1 atm.
A. Benzene-toluene
B. Ethyl alcohol-water
C. Hydrochloric acid-water
D. All of the above
Ethyl alcohol-water
Which of the following binary systems is an example of a maximum boiling azeotrope?
A. Water-hydrochloric acid
B. Acetone-carbon disulphide
C. Water-ethyl alcohol
D. N-heptane-n-octane
Water-hydrochloric acid
Ponchan-Savarit method analyses the fractional equipment based on
enthalpy and material balances
This phenomenon occurs in a fluid flow system when the local static pressure drops below the vapor pressure of the liquid at
the existing temperature, resulting to damage to pumps and control valves from the formation of “bubbles” or voids.
Cavitation
It is a membrane separation process where a component from a heated liquid phase permeates through the membrane and is removed under low pressure.
Pervaporation
A process where components are separated from each other using a semi-permeable membrane by virtue of their different diffusion rates through the membrane is referred to as
Dialysis
Floating head heat exchangers are used for
cases where temperature difference between the shell and the tubes is more
(>50 C)
In double pipe (concentric heat exchanger), the hydraulic radius for heat transfer (for a fluid flowing through the annulus) would be ___
more than that for fluid flow
Oxygen %wt in atmospheric is
23
Preheating of gaseous fuel results in increased
Flame Temperature
Production of sulfuric acid based on oxidation of sulfur to sulfur trioxide on a vanadium oxide catalyst
Contact Process
A disproportionation reaction of two aldehyde molecules to give an alcohol and a carboxylic acid
Canizzaro reaction
It is the solid , cellular, infusible material remaining after the carbonization of coal, pitch, petroleum residue and certain other carbonaceous materials.
coke
Inorganic residue that remains after the coal has been burned. Composed of silicon, aluminum, iron and Calcium. Also, compounds of magnesium, sodium, potassium and titanium are also present in minor amounts.
Ash
It is the portion of the coal which when heated ion the absence of air under prescribed conditions is liberated as gases or vapors
volatile matter
The gas generated by blasting a deep, hot bed of coal or coke continuously with a mixture of air and steam
producer gas
A mixture of hydrogen and carbon monoxide produced by the reaction of water and carbon (coke) that is used as a starting point in the synthesis of methanol and other organic chemicals
Synthesis gas
It converts solar energy into electricity directly
photovoltaic cell
An amorphous carbon that has been treated with steam until it has a great affinity for adsorbing many materials
Activated carbon
Dry air requirement for burning 1 ft3 for CO to CO2 may be around
2.4 ft3
Which of the following is an ore of mercury?
cinnabar
Lanolin is widely used in cosmetics, it is derived from _____
sheep’s wool
Other term for earthwax
Ozocerite
Process for the production of sodium carbonate from sodium chloride and calcium carbonate
Solvay
An early method for the production of sodium carbonate in which SO2 is oxidized to SO3 by nitrogen oxides in lead-lines chambers
Lead chamber process
An industrial process for the purification of aluminum (III) oxide through its selective dissolution in a strongly basic solution
Bayer process
Which of the following is true if the resulting combustible lost in refuse is coked coal?
has lost both moisture and VCM content
A gaseous fuel in order to develop luminosity on burning must contain
hydrocarbons
Which of the following is the most impotant deterrent in the extended use of pulverized coal in boiler firing?
ash disposal problem
The ejection of electrons from a metal surface by beam of light. The energy of electron depends upon the wavelength of the light.
photoelectric effect
Combined water is equal to
oxygen in the fuel
A solution contaning equimolal O2 and N2 is passed through a membrane to separate O2 from N2. The final product is found to contain 45% O2 and 55% N2. Find the %O2 remaining if only 20% of the original solution passed through the membrane
51%
An industrial process for the manufacture of ammonia from nitrogen and hydrogen with a catalyst at elevated temperature and pressure
Haber Bosch process
Which of the following metals is used as catalyst for the Haber-Bosch process of producing ammonia from nitrogen and hydrogen
gas?
Iron
A process used in paper production in which sulfur dioxide is added to a mildfly acidic digestion liquid to
sulfate process
Comparing sulfate process with sulfite process, we find that ___
T and P of sulfate process is greater than sulfite process
It is a by-product of the destructive distillation or pyrolysis of coal which is a mixture of many chemical compounds, mostly aromatic, which vary widely in composition
coal tar
A process for the conversion of iron to steal that consist of forcing air through molten pig iron
Bessemer process
Refers to the outgoing stream of noncombustible matter (ash) which separated from the materials that can be gasified
refuse
Refers to the outgoing stream of noncombustible matter (ash) which separated from the materials that can be gasified
refuse
Ore of Iron
hematite
Contact process when compared to chamber process for sulphuric acid manufacture
Yields higher concentration
Deaeration of water in its treament is necessary as it
Minimizes its corrosiveness
Dechlorination of treated water is necessary to
Remove chlorinous taste
Metallic soap is _____ salt of fatty acids
aluminum or calcium
20% oleum means that in 100 kg oleum, there are 20 kg of
SO3 and 80 kg H2SO4
Catalyst used in the manufacture of sulphuric acid by chamber and contact processes are respectively
Oxides of nitrogen & V2O5 on a porous carrier
This system usually encloses the device that involves mass flow such as compressor, turbine or nozzle
open system
Common microorganism used in penicillin production
mold
As the pipe diameter increases, the pumping cost
decreases
Industrial process for making hydrazine from ammonia
Raschig process
Ore of lead
galena
Most common baffle for shell and tube
25% cut segmental baffle
The minimum baffle height should be
twice the impeller diameter
Joint efficiency of seamless pipe
1.0
Ability of coal to withstand breakage
size stability
Which of the following is corundum?
aluminum oxide
Rectified spirits contains
95.6% alcohol
Percent kryption in air
0.0001139% by volume
Chemical formula of blue vitriol
CuSO4*5H2O
Chemical formula of saltpeter
Potassium nitrate, KNO4
Produced by reaction of calcium carbide with water
acetylene
Prussian blue
Ferric ferrocyanide
Calcite is
calcium carbonate
Commonly called niter cake
sodium bisulfate
Lime and soda ash are added to water to remove
bicarbonates and sulfates of calcium and magnesium
U
s
Which of the following compound is employed extensively in the leather industry as a depilatory?
sodium sulfide
Used to dissolve unaltered silver halogen compounds in negatives and prints
sodium thiosulfate
The ratio propeller agitator diameter to tank diameter is
0.15-0.30
In the case of s shell and the tube heat exchanger, the logarithmic mean temperature difference is_____
always less than arithmetic
Calcite is
calcium carbonate
Pearl ash chemical formula
K2CO3
Most common standard size of bubble caps
6” diameter with 4” diameter riser
In the design of a paddle agitator the ratio paddle agitator to tank diameter
0.8
Used as a disinfectant and deodorant in dairies, creameries, water supplies
sodium hypochlorite
The union of nonvolatile inorganic oxides resulting from the decomposition and fusion of alkali and alkaline earth compounds
glass
Glass that does not break when heated and then cooled
Tempered glass
The minimum plate spacing in most of the petroleum refinery distillation columns (if diameter 73 ft) is normally
18”
Comprises of a group of composite materials consisting of an intimate mixture of ceramic and metallic components, usually in the form of powder
cements
A product of alumina and silica at high temperature.
kaolinite
Twenty-five percent cut segmental baffle means that
the baffle height is 75% of the ID of the shell
In shell and tube heat exchanger, the clearance of the tube is generally
not less than one-fourth of the tube diameter or 3/16
Alloy of zinc and copper
brass
The ratio propeller agitator diameter to tank diameter is
0.15-0.30
Process for the production of aluminum through electrolysis of a solution of bauxite in molten cryolite
Hall-Heroult process
Multistep cyclic process in which pyruvate ions are broken down to carbon dioxide and water with production of atp nadh and fadh2
Citric acid cycle
A multistep cyclic process in which glucose is synthesized from carbon dioxide and water
Calvin cycle
Electrochemical process for obtaining sodium from molten sodium chloride
Downs process
Process in which sulfur is recovered from underground deposits by melting it with superheated water
Frasch process
Process used in paper production in which SO2 is added to yield hydrogen sulfite
Sulfite process
Neoprene is a
synthetic rubber
Partially decomposed plant matter that has accumulated underwater or in a water-saturated environment
Peat
Gas containing saturated paraffin hydrocarbons
Natural gas
The function of transducer is
Convert the primary signal into more useful quantity
A type of Portland cement that contains tricalcium silicate and dicalcium silicate.
Low Heat Cement
Stages of Design
- Possible design
- Plausible/ Feasible design
- Probable design
- Best design
Skirt supports are most suitable for:
Tall vertical vessels
Saddle supports are most suitable for:
Horizontal vessels
A disturbance which is externally applied to the system.
Perturbations
What is the simplest type of control commonly expressed as having on/off position action?
Bang-Bang
A control strategy where a primary controller, which controls the ultimate measurement, adjusts the setpoint of a secondary controller.
Cascade control
It is a control system used for multi-input and multi-output system.
Model predictive control (MPC)
Also known as design factor
Safety Factor
This dimensionless number relates buoyancy forces to viscous forces.
Grashoff number
In feedback control system for temperature control, a thermocouple measures the temperature and the output is fed to a controller. What results when one of the components known as a comparator compares a measured temperature value with desired value or set point?
Error
In agitation, which among the following will not prevent swirling or the formation of a vortex?
Installing baffles in the tank
The primary consideration in the selection of a dryer is:
Physical properties of the material to be dried
It is most efficient process for hydrogen gas production which emits less amount of carbon.
Steam reforming
Other name of Yamatake system
Azbil
Used in ultrasonic flowmeters
Doppler
Which equipment is non-proprietary?
-Distilling column
-Centrifuge
-Pumps
-Compressors
Distillation Column
(rest are proprietary or exclusive rights under manufacture)
When is partial condenser used in distillation?
If MVC have low boiling point, hence total condensation is difficult
In this distillation process the feed fluid is pressurized and heated and is then passed through a throttling valve or nozzle into a flash drum.
Flash / Equilibrium distillation
In this type of distillation, the still pot containing the mixture is heated and boiled slowly.
The vapor is withdrawn as soon as it is formed and is condensed to form the distillate.
Batch/Rayleigh Distillation
This type of distillation is used when the MVC has a high normal boiling temperature and is immiscible with water.
Steam Distillation
Rose oil is extracted from rose leaves using _____ distillation
Steam Distillation
when the solvent dissolves very little of solute then ____
large quantity of solvent is required to extract the solute
Flash distillation is the separation of components having ____
having very wide boiling points
Leaching of course solid lumps is also termed as ____
percolation
Relative volatility of a binary mixture is the ratio of vapor pressure of component A to that of component B when ____
Vapor phase obeys Dalton’s Law.
Liquid phase obeys Raoult’s Law
Large-scale uses of flash distillation is practiced in _____
petroleum refining
In an operating distillation column, ______ (describe driving forces)
driving force for the vapor flow is the PRESSURE DROP as the pressure decreases gradually from the bottom to the top of the column.
It is the first stage in the anatomy of a chemical manufacturing plant.
Raw Material Storage
Which among the following is not an exothermic process?
A. Methanol synthesis
B. Catalytic cracking
C. Oxidation of sulfur
D. Ammonia synthesis
Catalytic cracking
When designing a reactor what must be considered in searching for the optimum efficiency?
Economics of the overall process
What is the main goal of Chaddock who defined design as the conversion of an ill-defined requirement?
satisfied customer
In setting to optimize the engineering design of a system, what is considered as the overall objective in a chemical processing plant?
Maximize profits per unit time
Describe Analyses for Solid Fuels
Modified: M,C,net H,N,S,CW,Ash
VCM: C@VCM, net H, N, S, CW
Proximate: M, VCM, FC, Ash
Ultimate: C,H,O,N,S,Ash
Describe Orsat Analysis
CO2: potassium hydroxide KOH
Pyrogallol: O2
CO: cupric chloride
Ores:
Iron
Lead
Mercury
Aluminum
Uranium
Iron: Hematite
Lead: Galena
Mercury: Cinnabar
Uranium: Cleveite
Aluminum: Bauxite
Proximate Analysis:
Composition, Temperature and Time
M : 1 hr 104-110C
VCM : 7 mins 900C
FC : 2 hrs 500-815C
Ash : remaining
