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?

Related Mcqs:

1. Blast furnace gas is a very poisonous gas because of its predominantly high _______________ content?

   A. H2O
   B. CO2
   C. CO
   D. CH4

2. Furnace oil consumption in a furnace for a given duty employing preheated combination air (at 300°) may be reduced by about ______________ percent as compared to the use of atmospheric combustion air?

   A. 5
   B. 10
   C. 20
   D. 35

3. _____________ has the widest inflammability limit (explosion limit) of all the gases?

   A. Hydrogen
   B. Carbon monoxide
   C. Acetylene
   D. Methane

4. In general, the limit of inflammability/explosion limit of fuel gases is widened by the__________________?

   A. Increase in gas pressure
   B. Increase in temperature (i.e. preheating)
   C. Use of pure oxygen for combustion instead of air
   D. All A., B. & C.

5. Coke oven gas is a better fuel than blast furnace gas, because of its higher________________?

   A. Calorific value, cleanliness and relatively low distribution cost (due to its low specific gravity)
   B. Adiabatic flame temperature
   C. Heat release rate (thus requiring smaller combustion chamber)
   D. All A., B. and C.

6. A sample of natural gas containing 80% methane (CH4) and rest nitrogen (N2) is burnt with 20% excess air. With 80% of the combustibles producing CO2 and the remainder going to CO, the Orsat analysis in volume percent is_________________?

   A. CO2 : 6.26, CO : 1.56, O2 : 3.91, H2O :15.66, N2 : 72.60
   B. CO2 : 7.42, CO : 1.86, O2 : 4.64, N2:86.02
   C. CO2 : 6.39, CO : 1.60, O2 : 3.99, H2O:25.96, N2:72.06
   D. CO2 : 7.60, CO : 1.90, O2 : 4.75, N2 : 85.74

7. Blast furnace gas compared to coke oven gas has_________________?

   A. Lower ignition temperature
   B. Narrower limit of inflammability
   C. Higher calorific value
   D. Lower theoretical flame temperature

8. Coke oven gas compared to blast furnace gas is________________?

   A. More explosive and inflammable
   B. Less poisonous
   C. Lighter
   D. All A., B. and C.

9. 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?

   A. 15-30
   B. 1-2
   C. 70-100
   D. 150-200

10. Yield of blast furnace gas is about _______________ Nm3 /ton of pig iron?

    A. 300
    B. 2000
    C. 5000
    D. 10000