Fuels and Combustion The main function of primary air in pulverised coal fired burner is to Dry and transport the coal Preheat the tertiary air used for complete combustion of CO to CO₂ Have proper combustion by supplying it around the burner Burn CO to CO₂ Dry and transport the coal Preheat the tertiary air used for complete combustion of CO to CO₂ Have proper combustion by supplying it around the burner Burn CO to CO₂ ANSWER DOWNLOAD EXAMIANS APP
Fuels and Combustion Fuel gases containing hydrocarbons (ie.g. coke oven gas) are not preheated before burning, mainly because It reduces its flame temperature tremendously It reduces its calorific value tremendously There are chances of explosion during preheating The hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot It reduces its flame temperature tremendously It reduces its calorific value tremendously There are chances of explosion during preheating The hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot ANSWER DOWNLOAD EXAMIANS APP
Fuels and Combustion If oxygen content in the flue gas rises too high, fuel is being wasted by Dry gas/stack gas loss Moisture loss None of these Incomplete combustion Dry gas/stack gas loss Moisture loss None of these Incomplete combustion ANSWER DOWNLOAD EXAMIANS APP
Fuels and Combustion Bright coal Contains more than 90% durain Contains more than 90% fussain Is non-coking Contains mainly vitrain & clarain and is generally coking Contains more than 90% durain Contains more than 90% fussain Is non-coking Contains mainly vitrain & clarain and is generally coking ANSWER DOWNLOAD EXAMIANS APP
Fuels and Combustion Main constituent of natural gas is C₃H₈ CH₄ (upto 90%) H₂ C₂H₆ C₃H₈ CH₄ (upto 90%) H₂ C₂H₆ ANSWER DOWNLOAD EXAMIANS APP
Fuels and Combustion 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 reminder going to CO, the Orsat analysis in volume percent is CO₂ : 6.39, CO : 1.60, O₂ : 3.99, H₂O:25.96, N₂:72.06 CO₂ : 6.26, CO : 1.56, O₂ : 3.91, H₂O :15.66, N₂ : 72.60 CO₂ : 7.42, CO : 1.86, O₂ : 4.64, N₂:86.02 CO₂ : 7.60, CO : 1.90, O₂ : 4.75, N₂ : 85.74 CO₂ : 6.39, CO : 1.60, O₂ : 3.99, H₂O:25.96, N₂:72.06 CO₂ : 6.26, CO : 1.56, O₂ : 3.91, H₂O :15.66, N₂ : 72.60 CO₂ : 7.42, CO : 1.86, O₂ : 4.64, N₂:86.02 CO₂ : 7.60, CO : 1.90, O₂ : 4.75, N₂ : 85.74 ANSWER DOWNLOAD EXAMIANS APP
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