0% 0 Fuels and Combustion Quiz 6 1 / 50 Pitch creosote mixture (PCM) as compared to furnace oil is a better fuel, because its _____? Sulphur content is lower Flue gas has lower dew point thereby facilitating more waste heat recovery All A., B. and C. Emissivity factor is higher 2 / 50 Natural draft created by the chimney depends upon _______? Temperature of the flue gas Its height Both A. & B. Neither A. nor B. 3 / 50 Preheating of a gaseous fuel results in increased______? Flame temperature Quantity of flue gas Flame length Ignition temperature 4 / 50 Out of the following fuels, the difference between the net and gross calorific value is maximum in case of__________? Pitch Bituminous coal Blast furnace gas Fuel oil 5 / 50 Presence of phosphorous in metallurgical coal___________? Badly affects the quality of steel Increases its caking power Reduces its calorific value Is not undesirable 6 / 50 Pick out the wrong statement ? Reactivity of coke is inversely proportional to its absolute density Cokes of high reactivity are obtained from strongly coking coals Abrasion index of the coke is a measure of its hardness Cokes of high reactivity are obtained from weakly coking coals 7 / 50 Presence of free moisture in coal during its high temperature carbonisation _______? Increases the loss of fine coal dust from the ovens when charging Reduces the coking time Protects the volatile products from pyrolysis (cracking) in the presence of hot coke and hot oven walls None of these 8 / 50 Pick out the correct statement ? The less the oxygen content, better is the coal, as it reduces the calorific value All A., B. and C. Oxygen content decreases from lignite to bituminous coal as the coalification increases With increase in oxygen content, moisture holding capacity of coal increases and the caking power decreases 9 / 50 Pick out the wrong statement ? Specific gravity of coal increases with its increasing maturity Refractive index and reflectance of coal increases with the increasing rank of coal Angle of repose of coal increases with its increasing size Specific heat of coal decreases with increases in the volatile matter and decrease in the C/H ratio of coal 10 / 50 Out of the following, which is the most important parameter for the blast furnace grade coke ? Moisture content Volatile matter content CSR & CRI Ash content 11 / 50 Number of macrocomponents present in coal according to Stopes are _____? Six Two Four Five 12 / 50 Narrow coke ovens as compared to wider coke ovens__________? Produce smaller coke Require less time of carbonisation Produce stronger coke All A., B. and C. 13 / 50 Prime coking coal is always blended with medium or non- coking coal before carbonisation___________? To check against its excessive swelling during heating, which may exert high pressure and damage coke oven walls Both A. and B. Neither A. nor B. Because, it alone produces unreactive coke 14 / 50 Naphthalene is used for making__________? Drug intermediates e.g. ?-naphthol Unsaturated polyesters Insecticides (e.g. moth balls) All A., B. and C. 15 / 50 Pick out the wrong statement ? Low grade coal can be used, but generally high volatile matter coals are more suitable for making pulverised fuel Regulation of furnace temperature and atmosphere (oxidising or reducing) is easily possible with pulverised fuel firing Pulverised fuel can be completely burnt with less percentage of excess air compared to lump coal None of these 16 / 50 Naphthalene recovered from coke oven gas is used_____? As a fuel in furnaces For making electrodes As moth balls (insecticides) As moisture proof coating on fibres 17 / 50 Presence of free moisture in coal is most disadvantageous during__________? Combustion of fire slacks on the grates Handling (e.g. when emptying wagons) None of these Its pulverisation (as it requires more power) 18 / 50 Percentage of methane in coke oven gas may be around _______? 15 50 25 5 19 / 50 Net calorific value is the gross calorific value less the ________ heat of water in the product of combustion when cooled to 15?C ? Sensible Latent None of these Sensible and latent 20 / 50 Pick out the wrong statement ? Maximum yield of naphthalene is obtained on distillation of crude oil Each ton of petroleum oil on distillation produces about 30-50 Nm3 of gas The minimum temperature, at which a petroleum oil vapor catches fire and continues to burn, is called its flash point LPG is also used as fuel for automobiles & small furnaces and for cutting & welding of metals 21 / 50 Orsat apparatus is meant for _____? None of these Gravimetric analysis of flue gas Finding out combustion efficiency Direct determination of nitrogen in flue gas by absorbing it in ammoniacal cuprous chloride 22 / 50 Pensky-Marten apparatus is used for those oils, whose flash points are ______ ?F? < 90 > 120 < 120 90-110 23 / 50 Pick out the wrong statement ? Coals are divided in four species according to their carbon content in Seylor?s classification Carburetted water gas is also called blue gas Gross and net calorific value of a fuel is the same, if it does not contain hydrogen or hydrocarbons Carbonisation time in a by-product coke oven is about 16 hours 24 / 50 Producer gas comprises mainly of _________? CO & H2 CO2 & N2 CO & N2 CO2 & H2 25 / 50 Pick out the wrong statement ? Ash is normally removed as ?fly-ash? in Kopper-Totzek process of coal gasification Percentage of ash in coke produced from medium coking coal is more than that in coal The calorific value (kcal/Nm3) of coke oven gas reduces on removal of hydrogen from it by cryogenic method Coal based fertiliser plants in India at Talcher (Orissa) and Ramagundam (A.P) employ Kopper-Totzek process of coal gasification 26 / 50 Of the total tar present in raw coke oven gas, the tar recovered in primary cooler is about ________ percent? 55 25 75 5 27 / 50 Oxygen percentage (by weight) in atmospheric air is__________? 21 29 23 19 28 / 50 Presence of nitrogen in combustion air does not reduce the ______? Flame temperature Flue gas temperature Any of the above Amount of heat liberated 29 / 50 Pick out the wrong statement ? High concentration of oxygen in flue gas means high stack loss Calorific value of natural gas is more than that of LPG The ratio of fixed carbon to volatile matter percentage in coal is called its ?fuel ratio? Gaseous fuels require the least % excess air for complete combustion 30 / 50 Octane number of 2, 2, 4 ? trimethyl pentane is ___________? 100 0 More than 100 In between 0 and 100 31 / 50 Orsat apparatus___________? Gives flue gas analysis on dry basis Determines N2 in flue gas indirectly Can?t determine CO in flue gas, if it is < 0.2% All A., B. & C. 32 / 50 Preheating of _______ the flame temperature? Either the fuel or the air does not affect Either the fuel or the air or both, increases The gaseous fuel before combustion decreases Combustion air decreases 33 / 50 Producer gas containing least amount of tar is produced by the__________? High pressure gasification of coal (e.g. in Lurgi gasifier) Partial combustion of large size (< 50 mm) coke Partial combustion of coal Atmospheric pressure gasification of coal (e.g., in Kopper-Totzek gasifier) 34 / 50 Pick the odd man out? Pitch creosote mixture Oil gas Briquettes Wood 35 / 50 Oxygen content in a flue gas was found to be 4%. It implies that excess air used for combustion was around _______ percent? 96 40 4 20 36 / 50 Preheating of combustion air is done to _____? Increase the adiabatic flame temperature Reduce its requirement for effecting the complete combustion Complete the combustion of fuel Increase the calorific value of the fuel 37 / 50 Power alcohol as compared to straight run gasoline has lower _________? Calorific value Octane number Specific gravity Viscosity 38 / 50 Nitrogen in coal__________? All A., B. and C. Is present upto 1-2% Is recovered as ammonia during its carbonisation Comes from protein in parent vegetable matter 39 / 50 Out of the following fuels, the difference between gross and net calorific value will be minimum in case of_____? Natural gas Coke oven gas Blast furnace gas Water gas 40 / 50 Percentage of carbon monoxide in blast furnace gas may be around ______ ? 52 14 8 22 41 / 50 Nitrogen present in the flue gas is determined in the Orsat apparatus by absorbing it in_______? KOH Pyrogallol solution Ammoniacal cuprous chloride None of these 42 / 50 Oxygen required for theoretically complete combustion of 1 Nm3 methane is _______ Nm3? 1 2 4 6 43 / 50 Preheating of coal charge for the coke ovens reduces the ___________? All A., B. and C. Fuel consumption in coking Time of carbonisation Yield of gas and tar 44 / 50 Presence of _______ in a dry gaseous fuel does not contribute to its calorific value? Sulphur Carbon Oxygen Hydrogen 45 / 50 Percentage of hydrogen in coke oven gas may be around _____? 45 60 25 10 46 / 50 Pick out the wrong statement ? Burning the fuel with theoretically required amount of pure oxygen results in attainment of maximum adiabatic flame temperature Theoretical flame temperature is the temperature attained by the products of combustion, when the fuel is burned without loss or gain of heat Adiabatic flame temperatures of actual combustions are always less than the maximum values Burning the fuel with excess pure oxygen results in maximum theoretical flame temperature 47 / 50 Natural draught produced by a chimney depends upon the _______? Density of the chimney gases Neither A. nor B. Height of the chimney Both A. and B. 48 / 50 One kg of carbon for theoretically complete combustion requires _______ kg of air? 0.5 11.5 12 23 49 / 50 Percentage of nitrogen in blast furnace gas may be around___________? 25 80 55 5 50 / 50 Presence of force moisture in coal is most disadvantageous during its ___________? Transportation and handling Storage Pulverisation Washing Provide Your Information Your score is The average score is 0% LinkedIn Facebook Twitter 0% Restart quiz Send feedback Share on facebook Facebook Share on twitter Twitter Share on whatsapp WhatsApp PrevFuels and Combustion Quiz 5 Fuels and Combustion Quiz 7Next
