Quiz 4

Question 1

Provide the governing reactions for limestone scrubbing for SO2 removal

Answer 1

Limestone+ H20 + 2SO2 -> Ca + 2HSO3 + CO2

Question 2

Thiosulfate is used in the following FGD processes to oxidize SO2 to sulfate:

A) Forced oxidation system
B) Limestone scrubbing
C) Inhibited Oxidation
D) Magnesium Oxide process

Answer 2

C) Inhibited Oxidation

Question 3

Spray dryers are widely used in the process industries for SO2 removal. It is common practice to use following systems to collect particles:

A) ESP
B) Baghouse
C) Cyclone
D) Scrubbers

Answer 3

A) ESP
B) Baghouse

Question 4

Increasing Hg concentrations in the air has been growing concern in urban area. In general, FGD scrubber is used for Hg removal (20-60%) from exhaust gases. To meet Hg emission limits for new plants, what control technology you can apply to achieve more removal efficiency (>80%) ?

Answer 4

You could use intake control: Add activated carbon

Question 5

Mention three major sources of NOx emissions in the United States

Answer 5

Traffic, Power plants , (ADD)

Question 6

Provide the governing reactions of selective catalytic reduction (SCR) technique using CO agent for NOx removal. What catalysts are typically used for SCR technique?

Answer 6

Reduction
2NO + 2CO -> N2 + CO2

Question 7

Nitrogen content is high in the following fuel:

A) Heavy fuel
B) Light oil
C) Coal
D) Diesel

Answer 7

C) Coal

Question 8

A coal-burning power plant burns coal at a rate of 4000 tons/day. The ash content of the coal is 5%, and the sulfur content is 1.5% by weight. The rate of CaCO3 is needed to capture 90% of the SO2 generated is about: (atomic weights are C=12, O=16, S=32, Ca= 40)

A) 54 tons/day
C) 85 tons/day
D) 108 tons/day
C) 169 tons/day

Answer 8

C) 169 tons/day