⚙️Mechanical Engineering MCQs
Mechanical Engineering MCQs
488 MCQs461
Calorific value of coal is of the order of _______________________?
A200-400 kcal/kg
B800-1200 kcal/kg
C2000-4000 kcal/kg
D5000-8000 kcal/kg E. 8000-10,000 kcal/kg
462
Which is not correct statement about effect of sulphur in fuel ___________________?
Ait has heating value
Bit helps in electrostatic precipitation of ash in flue-gases
Cit leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low
Dit erodes furnace walls E. none of the above
463
Ultimate analysis of fuel is determination of percentage of____________________?
Acarbon, hydrogen, nitrogen, sulphur, moisture
Blower calorific value E. best analysis
Chigher calorific value
464
Spontaneous combustion is a phenomenon in which____________________?
Aall the fuel burns instantaneously producing high energy release
Bfuel burns with less air
Ccoal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal
Dexplosion in furnace E. none of the above
465
An economiser in a boiler______________________?
Aincreases steam pressure
Bincreases steam flow
Cdecreases fuel consumption
Ddecreases steam pressure E. increases life of boiler
466
Sulphur content of fuels is very important to the plant operators because it____________________?
Ahas high heating value
Bretards electric precipitation
Cpromotes complete combustion
Dhas highly corrosive effect E. facilitates ash removal
467
Gusset stays in a boiler are provided to____________________?
Aprevent the bulging of flat surfaces
Bavoid explosion in furnace
Cprevent leakage of hot flue gases
Dsupport furnace freely from top E. prevent atmospheric air leaking into furnace
468
Pour point of fuel oil is the____________________?
Alowest temperature at which oil will flow under set condition
Bstorage temperature
Ctemperature at which fuel is pumped through burners
Dtemperature at which oil is transported E. none of the above
469
The behaviour of coal in a furnace is determained by_______________________?
Athe content of sulphur
Bthe content of ash and heating value
Cthe proximate analysis
Dthe exact analysis E. its type
470
Sulphur in coal results in___________________?
Acausing clinkering and slagging
Bcorroding air heaters
Cspontaneous combustion during coal storage
Dfacilitating ash precipitation E. all of the above