A. Lengthens the flame
B. Causes heat loss of fuel by its partial combustion
C. Both A. & B.
D. Shortens the flame
Related Mcqs:
- During combustion of gaseous fuels, deficiency of air_________________?
A. Lengthens the flame
B. Tends to shorten the flame
C. Does not affect the flame length
D. Increases the flame temperature - Short/intense flame is produced during combustion of gaseous fuel by using________________?
A. High amount/current of combustion air
B. Low amount/current of combustion air
C. Preheated secondary air
D. Very little excess air - During combustion of a gaseous fuel, the presence of a non-luminous flame is an indication of the____________________?
A. Incomplete combustion
B. Complete combustion
C. High oxygen in flue gas
D. None of these - Use of excess of combustion air in the combustion of fuels results in__________________?
A. Heat losses
B. Long flame
C. Condensation of water vapour from the fuel gas
D. None of these - If the specific heat of gaseous products of combustion of a fuel is high, the abiabatic flame temperature will be_____________?
A. Low
B. High
C. Very high, if the fuel is of low calorific value
D. None of these - Which of the following is not increased by using preheated combustion air in place of ordinary air at room temperature ?
A. Calorific value of the fuel
B. Flame temperature achieved
C. Speed of combustion of fuel
D. Heat transfer rate to the stock in the furnace - 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 - 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 - 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 - A liquid/gaseous fuel containing hydrocarbons and high amount of sulphur is burnt with 40% excess air. The flue gas still contains large amount of carbon monoxide. This may be due to the_________________?
A. Presence of large quantity of hydrogen in the fuel
B. Low calorific value of the fuel
C. High sulphur content in the fuel
D. Lack of thorough mixing of fuel with air
