A. Use of coal/coke containing a high % of fines and ash
B. Use of fuel having too low an ash fusion temperature
C. Development of hot spots in the fuel bed and an abnormally high rate of gasification
D. All A., B. and C.
Related Mcqs:
- Temperature of a furnace fired with low calorific value fuel gas (i.e. lean gas) can be increased by______________________?
A. Preheating the combustion air
B. Oxygen enrichment of combustion air
C. Preheating the fuel gas
D. All A., B. & C. - Scaling of furnace stock is reduced by _______________ in flue gas?
A. CO
B. H2
C. High CO/CO2
D. All A., B. & C. - The thermal efficiency of an air/fuel gas preheating recuperator may be as high as _____________ percent?
A. 50
B. 65
C. 85
D. 99 - Main gas valve in a gaseous fuel burner is a ______________ valve?
A. Gate
B. Butterfly
C. Globe
D. None of these - Combustion of furnace oil in a furnace (soaking pit) with preheated combustion air at 400°C results in saving of about __________ percent furnace oil as compared to its combustion with atmospheric air, if the flue gas outlet temperature from the soaking pit is 1200°C ?
A. 5
B. 60
C. 20
D. 40 - Acid dew point temperature (ADT) of a flue gas produced by the combustion of a fuel containing 1% sulphur may be about ____________ °C?
A. 80
B. 130
C. 180
D. 250 - In producer gas making furnace, steam is added along with air to mainly control the____________________?
A. Fusion of coal ash & clinker formation
B. C. V. of producer gas
C. Temperature of producer gas
D. Tar content in producer gas - To reduce the stack loss, heat recovery from flue gas can be done by_____________________?
A. Preheating of cold stock
B. Preheating of combustion air
C. Steam generation in waste heat boilers
D. All A., B. and C. - Metallic recuperators are not used for waste heat recovery, if the hot flue gas temperature is above _____________ °C, because corrosion prevails at higher temperatures?
A. 350
B. 750
C. 1050
D. 1250 - Out of the following fuels used in a furnace exhausting flue gas at a temperature of 600°C, the percentage stack loss will be maximum in case of complete combustion of_________________?
A. Furnace oil with air
B. Furnace oil with oxygen
C. Blast furnace gas with air
D. Blast furnace gas with oxygen
