Ignition temperature of a fuel in air is ______________ that in pure oxygen?

Related Mcqs:

1. The maximum adiabatic flame temperature in air is _____________ the maximum flame temperature in pure oxygen?

   A. Lower than
   B. Higher than
   C. Same as
   D. Not related to

2. For the case of a fuel gas undergoing combustion with air, if the air/fuel ratio is increased, the adiabatic flame temperature will_____________________?

   A. Increase
   B. Decrease
   C. Increase or decrease depending on the fuel type
   D. Not change

3. Theoretical flame temperature of a fuel is that temperature which is attained, when the fuel is completely burnt ‘using theoretical amount of air in___________________?

   A. Air
   B. Oxygen
   C. Either A. or B.
   D. Either A. or B. without gain or loss of heat

4. Gasification of the solid fuel converts its organic part into combustible by interaction with air/oxygen and steam so as to obtain a secondary gaseous fuel of high calorific value having no ash. Gasification reactions are normally carried out at about _____________ °C?

   A. 400-500
   B. 900-1000
   C. 1400-1500
   D. 1700-1800

5. The maximum adiabatic flame temperature in air as compared to that in pure oxygen is_______________?

   A. Much lower
   B. Much higher
   C. Same
   D. Either lower or higher, depends on the type of fuel

6. The ratio of maximum adiabatic flame temperature in air to that in pure oxygen is always___________________?

   A. 1
   B. < 1
   C. > 1
   D. Unpredictable

7. Pure carbon is completely burnt in oxygen. The flue gas analysis is 70%CO2, 20%CO and 10%O2. The percent excess oxygen used is __________________?

   A. 20
   B. 12.5
   C. 0
   D. 10

8. A fuel containing carbon and carbon monoxide (but containing no hydrogen or its compounds) is burnt in pure oxygen at constant pressure. Its gross calorific value as compared to net calorific value will be_________________?

   A. More
   B. Less
   C. Same
   D. Data insufficient; can’t be predicted

9. Ignition temperature decreases progressively from anthracite to lignite, because___________________?

   A. Volatile matter content increases
   B. Carbon content decreases
   C. Moisture content increases
   D. Ash content increases

10. Oxygen content in a flue gas was found to be 4%. It implies that excess air used for combustion was around ______________ percent?

    A. 4
    B. 96
    C. 20
    D. 40