250+ TOP MCQs on Thermal Processes – Energy Recovery and Answers

Hazardous Waste Management Multiple Choice Questions on “Thermal Processes – Energy Recovery”.

1. Energy can be recovered from all types of wastes.
a) True
b) False
Answer: b
Clarification: To enable energy recovery, the waste must have sufficient heating value to reach appropriate combustion temperatures without need for additional fuel.

2. Energy recovery is typically via production of __________
a) Gas
b) Heat
c) Light
d) Steam
Answer: d
Clarification: Energy recovery is typically via production of steam which is driven through a turbine to produce electricity.

3. What is the maximum percent of energy recovered if the steam is condensed before reintroduced to system?
a) 25
b) 35
c) 45
d) 55
Answer: b
Clarification: The maximum percent of energy recovered if the steam is condensed before reintroduced to system is 35, because of condensing losses.

4. Energy recovery percentage depends on the type of waste.
a) True
b) False
Answer: b
Clarification: Energy recovery percentage will not depend on waste or method of combustion but on opportunities to sell low grade heat as well as energy.

5. Which of the following industrial process uses waste as a fuel?
a) Cement kilns
b) Lead manufacturing
c) Acid manufacturing
d) Sulphur manufacturing
Answer: a
Clarification: Heat and power plants, glass furnaces, steel manufacturing, lime and cement kilns uses wastes as a fuel or as a constituent part of the product.

6. What is the combustion temperature range in cement kiln incineration?
a) 1300-1600
b) 1350-1650
c) 1250-1450
d) 1235-1600
Answer: b
Clarification: The combustion temperature range in cement kiln incineration is 1350-1650 degree Celsius with long phase residence time up to 10 seconds.

7. Non-volatile heavy metals in kiln are fixed into __________
a) Clinker’s crystalline structure
b) Fumes
c) Solid lump
d) Slag
Answer: a
Clarification: The alkaline environment in the kiln absorbs and neutralizes acid gases and metals, non-volatile heavy metals in kiln are fixed into clinker’s crystalline structure.

8. Which of the following waste types are not suitable for co-combustion in cement kilns?
a) Chlorine
b) Hydrogen
c) Calcium
d) Carbonate
Answer: a
Clarification: Highly contaminated wastes, wastes with high water, chlorine, heavy metals or sulphur content waste types are not suitable for co-combustion in cement kilns.

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