0% 0 Fuels and Combustion Quiz 3 1 / 50 Coke oven gas after passing through return electrostatic tar precipitator (RETP) is used for the________? Mixing with blast furnace gas Coke oven battery heating Steel ladle drying Hot scarfing of steel slabs 2 / 50 Coal tar fuel ? 200 (CTF 200) is a mixture of ___________? Solar oil and pitch Anthracene and crecosote oil Light oil and pitch Pitch and creosote oil 3 / 50 During coal carbonisation process, the conversion of semi-coke to coke is accompanied by an increase in the ________ of the mass? Density None of these Electrical resistivity Porosity 4 / 50 Coking time in narrow by-product coke ovens is around _______ hours? 80 48 18 8 5 / 50 Coke oven gas is a better fuel than blast furnace gas, because of its higher_________? All A., B. and C. Calorific value, cleanliness and relatively low distribution cost (due to its low specific gravity) Adiabatic flame temperature Heat release rate (thus requiring smaller combustion chamber) 6 / 50 During its calorific value determination by bomb calorimeter, coal is combusted by __________? Air Oxygen None of these Oxygen enriched air 7 / 50 Coals used for the generation of producer gas should have ______? Low fusion point of ash Very low ash content (8-10%) High caking index High volatile matter content 8 / 50 Coal tar (produced by high temperature carbonisation) is the main source of__________? Aromatic compounds Aliphatic compounds Paraffins Olefins 9 / 50 Flue gas discharge velocity through chimney of a big thermal power plant may be around _________ m/sec? 50 500 10 0.5 10 / 50 For long flame and easy ignition, the coal used should have__________? High ash Low ash High volatile matter High calorific value 11 / 50 Deficiency of combustion air during combustion of a gaseous fuel_______? Causes heat loss of fuel by its partial combustion Both A. & B. Lengthens the flame Shortens the flame 12 / 50 Coking time in beehive coke oven is about _____? Two weeks 12 hours One week 2-3 days 13 / 50 Eschka mixture, which is used for the determination of sulphur in coal, is a mixture of _______? MgO & Na2CO3 MgCO3 & NaCl BaSO4 & NaCl MgSO4 & BaCl2 14 / 50 Correct viscosity of furnace oil at the burner tip for proper atomisation is about 25 centistokes. To reduce the viscosity of high viscosity furnace oil (250 centistokes) to the correct atomisation viscosity (i.e. 25 cst), it should be preheated to about _______?C? 85 105 70 145 15 / 50 Fischer-Tropsch method aims at the ________? None of these Synthesis of gasoline (from water gas) Gasification of coal Hydrogenation of coal to produce gasoline 16 / 50 Coal is pulverised before burning in large capacity boiler furnaces mainly to______ Provide trouble free operation Ensure its complete combustion Facilitate easy ash removal Enhance its calorific value 17 / 50 Dust content in raw blast furnace gas is about ________ gm/Nm3; hence it is cleaned to the dust level of about < 10 mg /Nm3 before use? 150-200 15-30 70-100 2-Jan 18 / 50 Coke having higher porosity has _____? All A., B. and C. Higher reactivity Lower bulk density Lower strength 19 / 50 Dry air requirement for burning 1 Nm3 of CO to CO2 may be around ________ Nm3 ? 11.4 2.4 1.75 0.87 20 / 50 For every 10% increase in the excess air; the fuel consumption increases by ________ percent? 0.2 1 0.1 0.5 21 / 50 Critical Air Blast (CAB) value of coke is a direct measure of its___________? Strength Hardness None of these Reactivity 22 / 50 Coking coals are invariably______? Bituminous coals Lignites Semi-anthracites Anthracites 23 / 50 Degree of carbonisation of coal during coke making can be roughly judged by the _______ of the coke produced? Colour Moisture content Ash content Volatile matter 24 / 50 Coke oven gas constitutes mainly of ______? H2 & CH4 H2 & CO2 H2 & CO CH4 & CO 25 / 50 Coking time in a commercial high temperature coal carbonisation plant is about _______ hours? 28 18 6 36 26 / 50 Coke compared to the coal from which it has been made, contains ______? Greater percentage of ash More carbon All A., B. and C. Less volatile matter 27 / 50 Coke ovens in steel plant are heated by _____? Coke oven gas Mixed gas Electricity Both B. & C. 28 / 50 During combustion of coal on grate, clinker formation is increased by the_____? Use of thick fire bed Low fusion point of ash (< 1100? C) All A., B. & C. Use of preheated primary air 29 / 50 Coke oven gas compared to blast furnace gas is_________? More explosive and inflammable Less poisonous Lighter All A., B. and C. 30 / 50 Coke oven gas is stripped of its H2S and mercaptans content by__________? Adsorption on silica gel Absorption in wash oil Adsorption on bog iron bed Bubbling it through dilute sulphuric acid 31 / 50 Coke oven gas burns with a yellowish flame, because of the presence of ___________? H2 CH4 CO2 NH3 32 / 50 Coal tar (produced by high temperature carbonization) is the main source of_________? Paraffins Aromatic compounds Olefins Submitted by:?Muhammad Mutsadiq Umer Aliphatic compounds 33 / 50 Efficient burning of anthracite coal requires________? High excess air Fine grinding Low preheat of air All A., B. and C 34 / 50 Flue gas obtained on complete combustion of pure acetylene (a hydrocarbon fuel) will contain ___________? CO2 Both B. & C. CO H2O 35 / 50 Combustion of pulverised coal as compared to that of lump coal _________? Provides a lower rate of heat release Develops a low temperature flame Develops a non-luminous flame Can be done with less excess air 36 / 50 Fixed carbon in coal is defined as________? The total quantity of carbon present in the coal The one which is present in the residue after combustion That present in volatile matters Hundred minus the percentage of volatile matter, ash and moisture 37 / 50 During combustion of a gaseous fuel, the presence of a non-luminous flame is an indication of the______? None of these High oxygen in flue gas Incomplete combustion Complete combustion 38 / 50 Coke oven gas produced by high temperature carbonisation of coal (as compared to that produced by low temperature carbonisation), has__________? Both A. and B. Lower hydrogen content Neither A. nor B. Higher calorific value 39 / 50 Coke made in narrower by-product coke ovens (as compared to wider ovens) is _______? Less reactive All A., B. & C. Stronger Smaller in size 40 / 50 Efficiency of the combustion of a fuel is judged by the _______ the flue gas? % of CO2 in % of O2in Temperature of Colour of 41 / 50 Combustion reaction of fuels is a/an _______ reaction? Exothermic None of these Auto catalytic Endothermic 42 / 50 Dry air required to burn 1 kg of carbon completely may be around _______ kg? 2 11 20 38 43 / 50 Coal tar fuels (CTF) as compared to petroleum based fuel oils have higher ___________? Calorific value Sulphur content Difference in gross & net calorific value Higher C/H ratio 44 / 50 Coalification means the _____? Direct hydrogenation of coal Complete combustion of coal Process of conversion of lignite into anthracite Underground gasification of coal 45 / 50 Flue gas from the heating chamber of by product coke ovens is removed by_________? Induced draft fan Natural draft Forced draft fan Steam ejector 46 / 50 During combustion of gaseous fuels, deficiency of air__________? Increases the flame temperature Lengthens the flame Does not affect the flame length Tends to shorten the flame 47 / 50 Emission of dense white smoke out of the chimney of a thermal power plant is an indication of the use of___________? Correct amount of air for combustion Too much air for combustion Less air for combustion Pulverised coal in boilers 48 / 50 Commercial production of petrol from coal (as practised in a factory at Sasol in South Africa) is done by the _________ of coal? Carbonisation Hydrogenation Gasification None of these 49 / 50 During coking of coal, the ash content (percentage)_________? Remain constant Increases Decreases None of these 50 / 50 Compound coke ovens are those which can be heated by ___________? Rich gas (e.g., coke oven gas) Both B. and C. Both steam and electrical power Lean gas (e.g., B.F. gas) 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 1 Fuels and Combustion Quiz 4Next
