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

Related Mcqs:

1. 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.

2. 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?

   A. 71%
   C. In between 37 & 71%
   D. None of these

3. Incomplete combustion of fuel in the furnace is judged by high _____________ of the flue gases?

   A. CO content
   B. Dew point
   C. CO2 content
   D. O2 content

4. 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___________________?

   A. Requirement of large volume combustion chamber
   B. Risk of explosion
   C. Chances of clinker formation
   D. Incomplete combustion of coal

5. High sulphur content in a fuel ______________ of the flue gases?

   A. Decreases the dew point
   B. Increases the dew point
   C. Reduces the combustion efficiency by limiting the permissible temperature reduction
   D. Both B. and C.

6. Which of the following fuel gases is heavier than air ?

   A. Blast furnace gas
   B. Coke oven gas
   C. Natural gas
   D. Water gas

7. Which of the following fuel gases has the highest calorific value ?

   A. Natural gas
   B. Coal bed methane (CBM)
   C. Liquefied petroleum gas (LPG)
   D. Sewage gas

8. Which of the following fuel gases will require maximum amount of air for combustion of 1 Nm3 gas ?

   A. Blast furnace gas
   B. Natural gas
   C. Producer gas
   D. Water gas

9. 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) ?

   A. Propane and acetylene
   B. Propane and LPG
   C. Sewage gas and gobar gas
   D. B.F. gas and coke oven gas

10. Fuel gases containing hydrocarbons (e.g. coke oven gas) are not preheated before burning, mainly because __________________?

    A. The hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot
    B. It reduces its calorific value tremendously
    C. It reduces its flame temperature tremendously
    D. There are chances of explosion during preheating