chemical engineering Mcqs
5751. Rate of low temperature oxidation of coal due to bad storage conditions_______________?
comments icon0
A. Is accelerated by storage in large heaps with small surface to volume ratio

B. Is more for low volatile coal compared to high volatile coal

C. Decreases with increase in surface area

D. Does not vary with increase in surface area

5752. Pick out the wrong statement ?
comments icon0

A. Cross-linked branched chain polymers are either elastometric or thermosetting

B. Linear polymers are formed from bifunctional groups only and are normally thermoplastic

C. ction</strong>

D. unctional monomer formulation reduces its solubility and increases the softening point

E. Branching in case of cross-linked polymers caused by small amount of impurities in

F. Dibasic acids reacts with dihydric alcohols to give polyesters using addition polymerisation
5753. Width of the coke oven towards coke side is slightly more than that on pusher side to____________________?
comments icon0

A. None of these

B. Increase the output of the coke

C. Facilitate easy discharging of coke as it swells during carbonisation

D. Facilitate uniform heating of the oven

5754. Low temperature oxidation of coal during storage does not decrease its__________________?
comments icon0

A. Caking power

B. None of these

C. Calorific value

D. Oxygen content

5755. Net calorific value is the gross calorific value less the _______________ heat of water in the product of combustion when cooled to 15C ?
comments icon0

A. None of these

B. Sensible and latent

C. Sensible

D. Latent

5756. A good coking coal should have high ______________ content?
comments icon0

A. Ash

B. Sulphur & phosphorus

C. None of these

D. Moisture

5757. Coke ovens in steel plant are heated by ___________________?
comments icon0

A. Electricity

B. Coke oven gas

C. Mixed gas

D. Both B. & C.
5758. Which of the following accentuates clinkering trouble on furnace grate burning coal ?
comments icon0

A. Low reactivity of carbonised residue containing high proportions of iron & sulphur

B. All A., B. and C.

C. Thick fire bed and preheated primary air

D. Low forced draught and fuel bed temperature

5759. Fuel can be defined as a substance which produces heat by___________________?
comments icon0
A. All A., B. & C.

B. Nuclear fission

C. Nuclear fusion

D. Combustion

5760. C/H ratio is the minimum in case of_________________?
comments icon0

A. Coal

B. Naphtha

C. Furnace oil

D. Natural gas
5761. Coke oven gas compared to blast furnace gas is________________?
comments icon0

A. More explosive and inflammable

B. All A., B. and C.

C. Less poisonous

D. Lighter

5762. ____________ process is meant for direct hydrogenation of coal to produce liquid fuel?
comments icon0

A. None of these

B. Lurgi

C. Bergius

D. Fischer-Tropsch

5763. Ignition temperature of a fuel in air is ______________ that in pure oxygen?
comments icon0
A. More than

B. Equal to

C. Less than

D. Either more or less; depends on the type of fuel

5764. Fireclay bricks are never used in the______________?
comments icon0

A. Beehive oven

B. Zinc roaster

C. Coke oven walls

D. Lead blast furnace

5765. Which of the following is not a micro component present in coal ?
comments icon0
A. Clarain

B. Micrinite

C. Fusinite

D. Liptinite

5766. The pyrogallol solution used in Orsat apparatus can absorb_________________?
comments icon0

A. Only O2

B. Both O2 and CO2

C. Both O2 and CO

D. All CO, CO2, and O2

5767. Which is the most stable crystalline form of silica at room temperature ?
comments icon0

A. Tridymite

B. Cristobalite

C. Quartz

D. None of these

5768. In chemical process equipments, the conical bottom heads used, usually has an apex angle of____________________?
comments icon0

A. 40

B. 80

C. 20

D. 60
5769. Which of the following has the lowest electrical resistivity ?
comments icon0
A. Graphite

B. Alumina

C. Fireclay

D. Zircon

5770. Bauxite calcining rotary kilns are lined with ________________ bricks?
comments icon0

A. Carbon

B. Corundum

C. Fireclay

D. 85% alumina
5771. High thermal conductivity of a refractory material is not important, when it is to be used in the______________________?
comments icon0

A. Coke oven regenerators

B. Blast furnace

C. Recuperators

D. Muffle furnace

5772. Pyrometric cone equivalent (PCE) value (Segar cone) of Superduty refractories is more than 33 which corresponds to a temperature of _____________ C?
comments icon0

A. 1670

B. 1520

C. 1630

D. 1730
5773. Grog__________________?
comments icon0

A. Contains both alumina and silica

B. Is crushed firebrick

C. Is a non-plastic material

D. All A., B. and C.
5774. Naphthalene is used for making_________________?
comments icon0

A. Insecticides (e.g. moth balls)

B. Drug intermediates e.g. ?-naphthol

C. All A., B. and C.

D. Unsaturated polyesters

5775. Silica bricks are attacked by basic slags at high temperature. Which of the following is not used solely as a binding material ?
comments icon0
A. Water

B. Plaster of Paris

C. Aluminium phosphate

D. Lime

5776. Carbon refractories have very high __________________?
comments icon0

A. Wetting characteristics

B. Refractoriness

C. Thermal conductivity

D. Both B. and C.
5777. Which is the stable form of silica upto 1470C ?
comments icon0
A. Tridymite

B. None of these

C. Cristobalite

D. Quartz

5778. Chemically, mullite refractories is____________________?
comments icon0

A. ThO2

B. Al2O3

C. 3Al2O3.2SiO2

D. ZrSO4

5779. Which of the following does not occur during firing/burning of refractories ?
comments icon0

A. Vitrification

B. Development of stable mineral form

C. Decrease in crushing strength

D. Removal of water of hydration

5780. If oxygen content in the flue gas rises too high, fuel is being wasted by _______________?
comments icon0

A. Moisture loss

B. Dry gas/stack gas loss

C. None of these

D. Incomplete combustion

5781. Out of the following fuels, the difference between gross and net calorific value will be minimum in case of___________________?
comments icon0
A. Blast furnace gas

B. Coke oven gas

C. Water gas

D. Natural gas

5782. One kg of carbon for theoretically complete combustion requires ______________ kg of air?
comments icon0
A. 11.5

B. 0.5

C. 23

D. 12

5783. Coal is heated in absence of air for 7 minutes at a temperature of about ______________ C, during its volatile matter determination for proximate analysis?
comments icon0
A. 950

B. 750

C. 1150

D. 550

5784. Coking time in a commercial high temperature coal carbonisation plant is about ______________ hours?
comments icon0

A. 6

B. 18

C. 36

D. 28

5785. Mineral matter, M and ash percentage A in coal are roughly related as_______________?
comments icon0

A. M = 1.8 A

B. M = 0.5 A

C. M = 1.1 A

D. M = A

5786. Panel test determines the _____________ of refractories?
comments icon0

A. Fusion point

B. Spalling resistance

C. Refractoriness under load (RUL)

D. Slag penetration resistance

5787. Froth floatation is used for_________________?
comments icon0
A. Washing fine coal dust (< 0.5 mm size)

B. Washing lump coal (> 80 mm size)

C. All A., B. and C.

D. Removing ash from the coal based on difference in specific gravity of coal and ash

5788. Anthracite can be used for___________________?
comments icon0
A. All A., B. and C.

B. m damage and to produce high strength coke

C. Recarbonising steel

D. Making carbon electrodes

E. Blending with highly coking coal to check its swelling which helps in saving coke even walls

5789. Higher efficiency in the combustion of solid fuel cannot be achieved by________________?
comments icon0

A. Proper fuel preparation

B. Keeping the flue gas exhaust temperature very high

C. Adopting efficient-fuel firing technique & equipment

D. Supplying correct quantity of combustion air

5790. Which is not an alumino-silicate refractory ?
comments icon0

A. Fireclay bricks

B. Mullite bricks

C. High alumina bricks

D. Tar dolomite bricks
5791. Too much of excess air in combustion results in high___________________?
comments icon0
A. All A., B. and C.

B. Stack gas temperature

C. Fuel consumption for the same heat load

D. Percentage of oxygen in flue gases

5792. The liquid used for the washing of coal in an industrial coal washery is a mixture of water and ____________________?
comments icon0

A. Carbon tetrachloride

B. Mineral oil of high viscosity & specific gravity (1.6)

C. Sand (40%)

D. None of these

5793. Periclase is___________________?
comments icon0

A. Amorphous magnesite

B. MgCO3

C. ZrSO4

D. Crystalline form of MgO
5794. Ferromagnetic ceramic material is not used in the__________________?
comments icon0

A. Magnetic switches

B. Transformers

C. Television sets

D. Thermal insulation
5795. Fusion point of coal ash generally varies from 1000 to 1700 C. Ash having fusion point less than _______________ C is liable to form clinker?
comments icon0
A. 1100

B. 1350

C. 1400

D. 1250

5796. Porosity is induced in insulating refractories by adding________________?
comments icon0

A. Powdered naphthalene

B. Calcium phosphate

C. Ammonium chloride/sulphate

D. All A., B. and C.
5797. Cermets are combination of ceramic and metallic materials due to which they have high strength & resistance to high temperature. Cermets are used in the_______________?
comments icon0

A. Insulation of high temperature furnaces

B. Nuclear reactors, missiles & space crafts

C. Roof of electric furnaces

D. Hearth of the blast furnace

5798. Grog addition in fireclay during brick manufacture is done to_________________?
comments icon0

A. Enhance the strength of fired refractories

B. Impart greater spalling resistance

C. Reduce its shrinkage on heating

D. All A., B. and C.
5799. A coal with high _____________ content, would ignite most easily?
comments icon0

A. Fixed carbon

B. Volatile matter

C. Ash

D. Oxygen

5800. Which refractory must have controlled atmosphere (temperature and humidity) for its safe storage ?
comments icon0

A. Mullite bricks

B. Tar bonded dolomite bricks

C. Magnesite bricks

D. Fireclay bricks