51. Degree of carbonisation of coal during coke making can be roughly judged by the __________ of the coke produced.
52. Ammonia content in raw coke oven gas is about __________ gm/Nm3.
53. Coal is heated in absence of air for 7 minutes at a temperature of about __________ °C, during its volatile matter determination for proximate analysis.
54. Quantity of coke oven gas produced by high temperature carbonisation of one ton of dry coal may be around __________ Nm3 .
55. Coking coals are invariably
56. Which of the following accounts for maximum energy loss in a boiler ?
57. 'Fuel' can be defined as a substance which produces heat by
58. Washing of coal
59. High ash coals
60. Which of the following is not a by-product fuel ?
61. Preheating of combustion air is done to
62. Gross heating value of coal is __________ the net heating value.
63. Anthracite can be used for
64. The calorific value of a gas of composition CO2 = 20%, H2 = 50%, CH4 = 30%, is y. If the composition of gas is changed to H2 = 50%, CH4 = 30%, CO2 = 10%, N2 = 10%, then the calorifice value will be
65. For which pair of the fuel gases, calorific value (C.V.) of one fuel is almost double that of the other on volume basis (i.e., kcal/Nm3 ), while the C.V. is same on weight basis (i.e., kcal/kg) ?
66. One kg of carbon for theoretically complete combustion requires __________ kg of air.
67. If CO2 is not fully absorbed by the KOH solution meant for its absorption in the orsat apparatus, it will appear as
68. By-products are __________ recovered in 'Beehive ovens'.
69. Use of pulverised coal in boiler furnace provides
70. Deficiency of combustion air during combustion of a gaseous fuel
71. Froth floatation is used for
72. (64-132) rank coal (ASTM) means a coal with 64%
73. The sequence of absorption in flue gas analysis by Orsat's apparatus is respectively
74. Which of the following is not a 'manufactured' fuel ?
75. Use of excess of combustion air in the combustion of fuels results in