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.Management Sciences
Category: Fuels and Combustion
C/H ratio is the maximum in case of_________________?
A. Coal
B. Furnace oil
C. Natural gas
D. Naphtha
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
During the carbonisation of coal__________________?
A. All tar is evolved at 700°C
C. Hard semi-coke starts shrinking at 600°C
D. All A., B. and C.
‘Fat’ coal means a coal having ___________________?
A. Low calorific value
B. High volatile matter
C. Low ash content
D. Non smoking tendency
The lowest temperature, at which a solid fuel produces enough vapors to support continuous combustion, is called ?
A. Fire point
B. Smoke point
C. Burning temperature
D. Kindling temperature
A travelling grate stoker is meant for the efficient burning of ______________ coal?
A. Caking
B. Pulverised
C. Non-caking
D. High ash
In high temperature carbonisation (as compared to low temperature carbonisation) of coal___________________?
A. Coke oven gas yield is more
B. Tar yield is less but free carbon in tar is more
C. Calorific value of coke oven gas is less
D. All A., B. and C.
For long flame and easy ignition, the coal used should have_________________?
A. High volatile matter
B. Low ash
C. High calorific value
D. High ash
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
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