81. Gusset stays in a boiler are provided to____________________?
A. prevent the bulging of flat surfaces
B. avoid explosion in furnace
C. prevent leakage of hot flue gases
D. support furnace freely from top
E. prevent atmospheric air leaking into furnace
82. Sulphur content of fuels is very important to the plant operators because it____________________?
A. has high heating value
B. retards electric precipitation
C. promotes complete combustion
D. has highly corrosive effect
E. facilitates ash removal
83. An economizer in a boiler______________________?
A. increases steam pressure
B. increases steam flow
C. decreases fuel consumption
D. decreases steam pressure
E. increases life of boiler
84. Spontaneous combustion is a phenomenon in which____________________?
A. all the fuel burns instantaneously producing high energy release
B. fuel burns with less air
C. coal 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
D. explosion in furnace
E. none of the above
85. Ultimate analysis of fuel is determination of percentage of____________________?
A. carbon, hydrogen, nitrogen, Sulphur, moisture
B. fixed carbon, ash, volatile matter, moisture
C. higher calorific value
B. lower calorific value
E. best analysis
86. Which device is used in thermal power plants to reduce level of pollution___________________?
A. induced draft fan
B. smoke meter
87. In ordetjo obtain superheated steam, a superheater is added in an existing boiler. As as result, furnace vacuum will _________________?
A. remain unaffected
B. improve C. worsen
C. may improve/worsen depending on size
88. The condition of steam in boiler drum is always ___________________?
89. Calorific value of coal is of the order of _______________________?
A. 200-400 kcal/kg
B. 800-1200 kcal/kg
C. 2000-4000 kcal/kg
D. 5000-8000 kcal/kg
E. 8000-10,000 kcal/kg
90. Boiler parameters are expressed by ___________________?
A. tones/hr. of steam
B. pressure of steam in kg/cm2
C. temperature of steam in °C
D. all of the above
E. none of the above