High pressure at the bottom of a distillation tower handling heat sensitive materials results in (A) Thermal decomposition of bottoms (B) Increased relative volatility (C) Erosion of the tower (D) Very efficient operation

High pressure at the bottom of a distillation tower handling heat

sensitive materials results in

(A) Thermal decomposition of bottoms

(B) Increased relative volatility

(C) Erosion of the tower

(D) Very efficient operation


by

1 Answer

Answer :

(A) Thermal decomposition of bottoms

by

Related questions

Crude oil is subjected to vacuum distillation in the last stage, because (A) High boiling point products like heavy fuel oil & lubricating oils are heat sensitive and may decompose (B) Lighter/low boiling products are prone to thermal decomposition (C) High purity products can be obtained thereby (D) None of these

Description : Crude oil is subjected to vacuum distillation in the last stage, because (A) High boiling point products like heavy fuel oil & lubricating oils are heat sensitive and may decompose (B) Lighter/low ... prone to thermal decomposition (C) High purity products can be obtained thereby (D) None of these

Last Answer : (A) High boiling point products like heavy fuel oil & lubricating oils are heat sensitive and may decompose

According to the Fenske equation, what will be the minimum number of plates required in a distillation column to separate an equimolar binary mixture of components A and B into an overhead fraction containing 99 mol% A and a bottom fraction containing 98 mol% B ? Assume that relative volatility (αAB = 2) does not change appreciably in the column. (A) 5 (B) 9 (C) 12 (D) 28

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Last Answer : (C) 12

Molecular distillation is (A) High temperature distillation (B) For heat-sensitive materials (C) Very low pressure distillation (D) Both (B) and (C)

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If the amount of the steam used in steam distillation is increased, the temperature of distillation (A) Increases (B) Decreases (C) Remains unchanged (D) Depends on relative volatility

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Entrainer used in Azeotropic distillation should (A) Form a low boiling azeotrope with one of the constituents of the mixture (B) Form a new azeotrope of low relative volatility with one of the constituents of the mixture (C) Have high latent heat of vaporisation (D) Have high viscosity to provide high tray efficiency

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For a binary mixture with low relative volatility, (A) Use steam distillation (B) Use molecular distillation (C) Use high pressure distillation (D) An azeotrope may be formed during distillation

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Heat sensitive materials with very high latent heat of vaporisation may be economically separated using (A) Liquid extraction (B) Distillation (C) Evaporation (D) Absorption

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Pick out the wrong statement. (A) Constant pressure distillation cannot separate an Azeotropic mixture (B) Relative volatility of a binary mixture changes appreciably with the minor change in temperature (C) The relative volatility of a binary mixture at Azeotropic composition is unity (D) Flash distillation is practised on wide spread scale in petroleum refinery

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Solvent used in extractive distillation (A) Changes the relative volatility of the original components (B) Should be of high volatility (C) Should form azeotropes with the original components (D) All (A), (B) and (C)

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In extractive distillation, solvent is (A) Added to alter the relative volatility of the mixture (B) Of high volatility (C) Present in overhead stream (D) Of high viscosity to give high tray efficiency

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Last Answer : (A) Added to alter the relative volatility of the mixture

Solvent used in extractive distillation (A) Is of low volatility (B) Forms a low boiling azeotrope (C) Forms a high boiling azeotrope (D) Does not alter the relative volatility of the original components

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In a binary system, separation is very efficient, when the relative volatility is (A) 1 (B) > 1 (C) < 1 (D) 0.5

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Last Answer : (B) > 1

Pick out the correct statement. (A) Ponchan-Savarit method is more accurate than McCabe-Thiele method to determine the number of theoretical stages required for the separation of non￾ideal binary system by distillation (B) A sharp decrease in pressure drop is an indication of flooding in a distillation coloumn (C) Solvent used in extractive distillation should be of high volatility (D) Flash distillation is suitable for separating components which have very close boiling temperature

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Fenske-Underwood equation used for calculating the minimum number of theoretical plates in distillation column is valid for (A) Constant molal overflow (B) Total reflux (C) Constant relative volatility (D) All (A), (B) and (C)

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Last Answer : (D) All (A), (B) and (C)

The-relative volatility for separation of a non-ideal binary mixture by distillation should be (A) 0 (B) 1 (C) > 1 (D) < 1

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Fenske equation for determining the minimum number of theoretical stages in distillation column holds good, when the (A) Relative volatility is reasonably constant (B) Mixture (to be separated) shows negative deviation from ideality (C) Mixture (to be separated) shows positive deviation from ideality (D) Multi-component distillation is involved

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Last Answer : (A) Relative volatility is reasonably constant

In case of __________ distillation, a solvent is added to alter the relative volatility of the mixture to be separated. (A) Molecular (B) Azeotropic (C) Extractive

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Separation of two volatile liquids by distillation makes use of their (A) Selectivity (B) Relative volatility (C) Solubility (D) Density difference

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Pick out the wrong statement: (A) The capacity of an evaporator is reduced by the boiling point elevation (B) Corrosive liquid is normally passed through the tubes in a shell and tube heat exchanger (C) Steam jet ejector is used for vapor compression in a thermal recompression evaporator (D) Heat sensitive materials should be concentrated in high pressure evaporators

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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

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The reason for preferring packed towers over plate towers in distillation practice is that the packed tower operation gives (A) Low pressure drop and high hold up (B) High pressure drop and low hold up (C) Low pressure drop and low hold up (D) High pressure drop and high hold up

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Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the possibility of tower wall collapse (B) Packed towers are preferred over plate towers for handling corrosive and foamy liquids (C) Diameter of randomly packed tower is normally more than 1.2 metres (D) Due to uneven supply and improper distribution of liquid, problem of channelling, loading & flooding is generally encountered in packed towers

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When the mixture to be distilled has a very high boiling point and the product material is heat sensitive, the separation technique to be used is __________ distillation. (A) Continuous (B) Steam (C) Azeotropic (D) None of these

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Dowtherm is a (A) High temperature heating medium (a petroleum product) (B) Product of coal tar distillation (C) Very heat sensitive material (D) None of these

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The slope of 9-line is determined by the (A) Reflux ratio (B) Plate efficiency to be achieved (C) Thermal condition of the feed (D) Relative volatility

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Vacuum is generally maintained in the vapour space of an evaporator mainly to (A) Get economical temperature difference by using moderate pressure steam (B) Facilitate forward feeding in multiple effect evaporation (C) Concentrate heat sensitive materials (D) Achieve very high concentration of the final product

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Heat exchangers operating, when the asymptotic range is reached, (A) Provide very large heat transfer co-efficient (B) Results in making part of the heating surface inactive (C) Results in abruptly increased velocity (D) None of these

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Distillation at reduced pressure is used for liquids which (a) Have high boiling points (b) Have low boiling points (c) Have high volatility (d) Decompose before their boiling points

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Pick out the correct statement. (A) Higher hold up of the solid in the rotary dryer results in better exposure of the solids to the gas (B) The 'Hatta number' is important in problems involving gas absorption without chemical reaction (C) For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both components is linear in the case of steady state equimolal counter-diffusion (D) Total reflux in case of distillation operation requires infinite number of plates for a binary system separation

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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

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With increase in pressure, the relative volatility for a binary system (A) Increases (B) Decreases (C) Remains same

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When the liquid phase and vapour phase of a binary system obeys Raoult's and Dalton's law respectively, the relative volatility is the ratio of (A) Vapour pressure of component A to that of component B (B) Vapour pressure of component A to the total pressure (C) Vapour pressure of component A to the partial pressure of A (D) Partial pressure of component A to the total pressure

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Relative volatility varies with the concentration of component for an ideal solution. The relative volatility of a binary mixture may be defined as the ratio of vapor pressure of component 'A' to that of component 'B', when (A) Only vapor phase follows Raoult's law (B) Only liquid phase obeys Dalton's law (C) Liquid phase obeys Dalton's law and vapor phase obeys Raoult's law (D) Vapor phase obeys Dalton's law and liquid phase obeys Raoult's law

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Description : The relative volatility of a binary mixture at constant temperature __________ the total pressure. (A) Decreases with increase in (B) Increases with increase in (C) Is independent of (D) None of these

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Heat sensitive materials can be concentrated in an evaporator employing (A) Vacuum (B) High pressure (C) High residence time (D) None of these

Description : Heat sensitive materials can be concentrated in an evaporator employing (A) Vacuum (B) High pressure (C) High residence time (D) None of these

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Heat sensitive materials can be concentrated in an evaporator employing (A) Vacuum (B) High pressure (C) High residence time (D) None of these

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A distillation column with N plates is being operated under normal conditions. At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped). At the new steady state, (A) Composition of vapors and that of liquid do not vary throughout the column (B) Reboiler load and condenser load are minimum (C) The top and bottom compositions are unchanged with and without total reflux (D) The top and bottom compositions correspond to the maximum enrichment available

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Last Answer : (D) High reflux ratio

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Choose the correct statement regarding thermal cracking. (A) Moderate changes in operating temperature does not change the depth of cracking (B) Increased residence time results in the decreased severity of cracking (C) At low pressure, the yield of lighter hydrocarbons are more (D) Greater depth of cracking gives lower octane number gasoline

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When testing for blown fuses in a three-phase supply circuit to a motor, you should first ___________________. A. apply the megger across the tops of the line fuses B. apply an ammeter diagonally across the top of the first line fuse and the bottom of the third line fuse C. apply the voltage tester across the bottoms of the line fuses D. ensure the circuit is de-energized, and then use a continuity tester

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Which of the following physical distribution functions involves the design and operation of facilities for storing and moving goods? A)Order processing B)Materials handling C)Transportation D)Warehousing E)Inventory management

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The reciprocal of stripping factor is termed as (A) Selectivity index (B) Relative volatility (C) Absorption factor (D) Murphree efficiency

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