Description : The function of an economiser in a boiler is to preheat the (A) Feedwater (B) Combustion air (C) Pulverised coal (D) Furnace oil
Last Answer : (A) Feedwater
Description : The main function of primary air in pulverised coal fired burner is to (A) Burn CO to CO2 (B) Dry and transport the coal (C) Have proper combustion by supplying it around the burner (D) Preheat the tertiary air used for complete combustion of CO to CO2
Last Answer : (B) Dry and transport the coal
Description : Which of the following is unsuitable fuel for producer gas manufacture? (A) Coke (B) Anthracite (C) Coal having low fusion point of its ash (D) Coal having high fusion point of its ash
Last Answer : (C) Coal having low fusion point of its ash
Description : During root welding, which of the following would be the main cause of excess penetration? a) The root gap is too small in accordance with WPS b) Preheat not used c) The current is too high d) Root face is too large
Last Answer : c) The current is too high
Description : Function of secondary air in pulverised coal firing is to (A) Transport the coal to the burner (B) Dry the coal (C) Ensure efficient burning of coal around the burner (D) Reduce primary air requirement
Last Answer : (C) Ensure efficient burning of coal around the burner
Description : Which of the following is the most reactive (as regards the formation of CO + H2 from C + H2O)? (A) Blast furnace coke (B) Low temperature coke (C) Anthracite coal (D) Sub-bituminous coa
Last Answer : (B) Low temperature coke
Description : A travelling grate stoker is meant for the efficient burning of __________ coal. (A) Caking (B) Pulverised (C) Non-caking (D) High ash
Last Answer : (C) Non-caking
Description : Which of the following would require least amount of secondary air for combustion? (A) Coke breeze containing 25% ash and 2% volatile matter (B) Anthracite containing 10% volatile matter and 8% ash ... ash and 25% volatile matter (D) Semi-bituminous coal containing 25% ash and 20% volatile matter
Last Answer : (A) Coke breeze containing 25% ash and 2% volatile matter
Description : Which of the following accentuates clinkering troubles on furnace grate burning coal? (A) Low reactivity of carbonised residue containing high proportion of iron & sulphur (B) Low forced draft & fuel bed temperature (C) Thick firebed and preheated primary air (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Which of the following accentuates clinkering trouble on furnace grate burning coal? (A) Low reactivity of carbonised residue containing high proportions of iron & sulphur (B) Low forced draught and fuel bed temperature (C) Thick fire bed and preheated primary air (D) All (A), (B) and (C)
Description : Pick out the wrong statement. (A) Pulverised fuel can be completely burnt with less percentage of excess air compared to lump coal (B) Low grade coal can be used, but generally high volatile ... and atmosphere (oxidising or reducing) is easily possible with pulverised fuel firing (D) None of these
Last Answer : (D) None of these
Description : The difference between total carbon and fixed carbon of coal will be minimum in case of (A) Lignite (B) Bituminous coal (C) Anthracite (D) High temperature coke (V.M < 0.5%)
Last Answer : (D) High temperature coke (V.M < 0.5%)
Description : Anthracite can be used for (A) Recarbonising steel (B) Making carbon electrodes (C) Blending with highly coking coal to check its swelling which helps in saving coke even walls from damage and to produce high strength coke (D) All (A), (B) and (C)
Description : A coal having high ratio of volatile matter to fixed carbon as compared to a coal having low ratio of volatile matter to fixed carbon (A) Is less liable to spontaneous combustion on storage (B) ... a shorter flame (C) Requires smaller combustion space and less secondary air (D) None of these
Description : Producer gas is obtained by A. partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast B. carbonisation of bituminous coal C. passing steam over incandescent coke D. passing air and a large amount of steam over waste coal at about 650°C
Last Answer : Answer: A
Description : Defect of low joint is due to? (i) Excess height (ii) Early trimming of weld (iii) Early grinding of weld (iv) Nil/Less provision of height during alignment.
Last Answer : (iv) Nil/Less provision of height during alignment.
Description : Acid rains are produced by (a) excess NO2 and SO2 from burning fossil fuels (b) excess production of NH3 by industry and coal gas (c) excess release of carbon monoxide by incomplete combustion (d) excess formation of CO2 by combustion and animal respiration.
Last Answer : (a) excess NO2 and SO2 from burning fossil fuels
Description : Air-refrigeration cycle (A) Is the most efficient of all refrigeration cycles (B) Has very low efficiency (C) Requires relatively large quantities of air to achieve a significant amount of refrigeration (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : Combustion of pulverised coal as compared to that of lump coal (A) Develops a non-luminous flame (B) Develops a low temperature flame (C) Can be done with less excess air (D) Provides a lower rate of heat release
Last Answer : (C) Can be done with less excess ai
Description : Black smoke coming out of the chimney of a furnace is an indication of the use of __________ in the furnace. (A) Low amount of excess combustion air (B) Large quantity of excess combustion air (C) Hydrocarbon fuel (D) Pulverised coal as fuel
Last Answer : (A) Low amount of excess combustion air
Description : Equilibrium moisture of a solid is equal to the total moisture minus free moisture. Which of the following substances will have maxi-mum equilibrium moisture? (A) Anthracite coal (B) Rag paper (C) Bamboo (D) Inorganic solids
Last Answer : (C) Bamboo
Description : Anthracite coal (A) Contains more volatile matter than bituminous coal (B) Ignites more easily than bituminous coal (C) Is essentially a coking coal (D) Burns with short, bluish, yellow-tipped flame producing very little smoke
Last Answer : (D) Burns with short, bluish, yellow-tipped flame producing very little smoke
Description : Which of the following can be made into briquettes without the use of a binder? (A) Lignite (B) Bituminous coal (C) Anthracite coal (D) None of these
Last Answer : (A) Lignite
Description : Which of the following has the highest calorific value? (A) Lignite (B) Sub-bituminous coal (C) Anthracite (D) Peat
Last Answer : (C) Anthracite
Description : The most matured coal out of the following is (A) Lignite (B) Semi-anthracite (C) Sub-bituminous (D) Bituminous
Last Answer : (B) Semi-anthracite
Description : Calorific value of a typical dry anthracite coal may be around __________ Kcal/kg. (A) 1000 (B) 4000 (C) 8000 (D) 15000
Last Answer : (C) 8000
Description : Hard coke is manufactured from (A) Lignite (B) Bituminous coal (C) Semi-anthracite (D) Anthracite
Last Answer : (B) Bituminous coal
Description : Which will have the least volatile matter and hence will be the most difficult to ignite? (A) Bituminous coal (B) Coke (C) Semi-bituminous coal (D) Anthracite
Last Answer : (B) Coke
Description : Which is the most matured coal? (A) Lignite (B) Bituminous (C) Semi-anthracite (D) Anthracite
Last Answer : (D) Anthracite
Description : Bituminous coal (A) Ignites less easily than anthracite (B) Is generally coking (C) Burns with smoky yellow flame (D) Both (B) and (C)
Description : Coalification means the (A) Process of conversion of lignite into anthracite (B) Underground gasification of coal (C) Complete combustion of coal (D) Direct hydrogenation of coa
Last Answer : (A) Process of conversion of lignite into anthracite
Description : The high strength of rapid hardening cement at early stage, is due to its (A) Finer grinding (B) Burning at high temperature (C) Increased lime cement (D) Higher content of tricalcium
Last Answer : Answer: Option C
Description : Grindability index of a coal is 100. It implies that the (A) Coal can be pulverised with great difficulty (B) Coal can't be pulverised (C) Coal can be easily pulverised (D) Power consumption in grinding the coal will be very high
Last Answer : (C) Coal can be easily pulverised
Description : Defect of High joint is due to ? (i) Early trimming of weld (ii) Excess provision of height during alignment.* (iii) Early grinding of weld (iv) None of above
Last Answer : (ii) Excess provision of height during alignment.
Description : Colloidal mills are used for __________ grinding. (A) Coarse (B) Intermediate (C) Fine (D) Ultrafine
Last Answer : (D) Ultrafine
Description : Which of the following crushing laws is most accurately applicable to the fine grinding of materials? (A) Bond's crushing law (B) Kick's law (C) Rittinger's law (D) None of these
Last Answer : (C) Rittinger's law
Description : Ball mill is used for (A) Crushing (B) Coarse grinding (C) Fine grinding (D) Attrition
Last Answer : (C) Fine grinding
Description : The advantages of firing pulverised coal in the furnace lies in the fact that, it (A) Permits the use of high ash content coal (B) Permits the use of low fusion point ash coal (C) Accelerates the burning rate and economises on fuel consumption (D) All (A), (B) and (C)
Last Answer : (C) Accelerates the burning rate and economises on fuel consumption
Description : The advantage of firing pulverised coal in the furnace lies in the fact, that it (A) Permits the use of high ash content coal (B) Permits the use of low fusion point ash coal (C) Accelerates the burning rate and economises on fuel combustion (D) All (A), (B) and (C)
Last Answer : (C) Accelerates the burning rate and economises on fuel combustion
Description : Size of the combustion chamber of a furnace depends upon the (A) Heat release rate of the fuel (B) Preheat temperature of fuel & air (C) Method of mixing the fuel & air (D) All (A), (B) and (C)
Description : The amount of combustible escaping unconsumed from the furnace, depends upon the (A) Air supplied and furnace temperature (B) Burner design (thoroughness of mixing versus stratification) (C) Air preheat and the flow of ... , by acceleration or by change of direction) (D) All (A), (B) and (C)
Description : Wet grinding in a revolving mill __________ as compared to dry grinding. (A) Gives less wear on chamber walls (B) Requires more energy (C) Increases capacity (D) Complicates handling of the product
Last Answer : (C) Increases capacity
Description : In case of a revolving mill, wet grinding compared to dry grinding (A) Requires more energy (B) Has less capacity (C) Complicates handling & classification of the product (D) None of these
Description : Pick out the wrong statement. (A) High concentration of oxygen in flue gas means high stack loss (B) Gaseous fuels require the least % excess air for complete combustion (C) The ratio of fixed carbon to ... coal is called its 'fuel ratio' (D) Calorific value of natural gas is more than that of LPG
Last Answer : (D) Calorific value of natural gas is more than that of LPG
Description : Overfire burning in a furnace is a phenomenon characterised by (A) Supply of excess fuel (B) Supply of excess air (C) Burning carbon monoxide and other incombustible in upper zone of furnace by supplying more air (D) None of these
Last Answer : (C) Burning carbon monoxide and other incombustible in upper zone of furnace by supplying more air
Description : Overfire burning" in a furnace is a phenomenon characterised by the (A) Supply of excess fuel (B) Supply of excess air (C) Burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying more air (D) None of these
Last Answer : (C) Burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying more air
Description : For efficient grinding, ball mills must be operated (A) At a speed less than the critical speed (B) At a speed more than the critical speed (C) At a speed equal to the critical speed (D) With minimum possible small balls
Last Answer : (A) At a speed less than the critical speed
Description : Which one of the following lists four type of coal, arranged in the increasing order of their carbon content? (a) Peat, Lignite, Bituminous, Anthracite (b) Peat, Bituminous, Lignite, Anthracite (c) Lignite, Peat, Bituminous, Anthracite (d) Peat, Anthracite, Lignite, Bituminous
Last Answer : Ans: (a)