26. Explosion limit of blast furnace gas is 37 to 71% gas in gas-air mixture. It means that the blast furnace gas will explode when burnt in a confined space, if its concentration in the gas-air mixture is __________ percent.
27. Prime coking coal is always blended with medium or non- coking coal before ear-bonisation
28. Actual flame temperature is always lower than the adiabatic flame temperature, because there is
29. Fuel gases containing hydrocarbons (ie.g. coke oven gas) are not preheated before burning, mainly because
30. Which of the following is the most reactive (as regards the formation of CO + H2 from C + H2O) ?
31. Calorific value of coal middling generated in coal washeries during washing of coal may be around __________ Kcal/kg.
32. Flue gas discharge velocity through chimney of a big thermal power plant may be around __________ m/sec.
33. Which of the following is used for making the explosive 'TNT' ?
34. Adiabatic flame temperature of a fuel is dependent on the initial temperature of
35. Which of the following gaseous fuels has the lowest calorific value ?
36. Which of the following is not a by-product recovered in a high temperature coal carbonisation plant ?
37. Pensky-Marten apparatus is used for those oils, whose flash points are __________ °F.
38. In high temperature carbonisation of coal compared to low temperature carbonisation
39. When incomplete combustion loss is high, the flue gas analysis shows large amount of
40. The gas which contributes maximum to the heating value of natural gas is
41. The temperature at which plastic layer formation takes place during carbonisation of coal varies from __________ °C.
42. Yield of coke oven gas in low temperature carbonisation of coal is about __________ Nm3 /ton of dry coal.
43. Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the
44. Blast furnace coke is made from coal by
45. Yield of blast furnace gas is about __________ Nm3 /ton of pig iron.
46. Coke oven gas is stripped of its H2S and mercaptans content by
47. In Lurgi coal gasifier,
48. Mineral matter content (M) and ash content (A) in coal are approximately related as
49. When steam is passed over coal resulting in the endothermic reaction represent by, C + H2O = CO + H2, it is called the __________ of coal.
50. Dry air requirement for burning 1 Nm3 of CO to CO2 may be around __________ Nm3.