1. 100°C
2. above dew-point temperature of flue gases
3. below dew-point temperature of flue gases
4. less than wet bulb temperature of flue gases
above dew-point temperature of flue gases
1. from a metal wall from one medium to another
2. from heating an intermediate material and then heating the air from this material
3. by direct mixing
4. heat is transferred by bleeding some gas from furnace
from heating an intermediate material and then heating the air from this material
1. approach temperature should be as low as possible
2. handling and maintenance should be easier
3. heat transfer area should be optimum
4. stack gases should not be cooled to the dew point
stack gases should not be cooled to the dew point
1. more
2. less
3. equal
4. may be more or less depending on capacity of reheated
less
1. create vacuum
2. inject chemical solution in feed pump
3. pump water, similar to boiler feed pump
4. add make up water in the system
pump water, similar to boiler feed pump
1. higher value
2. lower value
3. same value
4. any value
lower value
1. the draft to be created
2. limitation of construction facilities
3. control of pollution
4. quantity of flue gases to be handled
control of pollution
1. boiler drum
2. super-heater tubes
3. a separate coil located in convection path
4. a separate coil
a separate coil located in convection path
1. more
2. equal
3. less
4. could be more or less depending on the size of plant
less
1. desirable
2. economical
3. uneconomical
4. optional
uneconomical