Question

A West Virginia coal is burned at a rate of 8.02 kg/s. The coal has a sulfur content of 4.40 % and the bottom ash contains 2.80 % of the input sulfur. What is the annual rate (in kg/yr) of stack emissions of SO2

Answer 1

Answer: The annual emission rate of SO2 is 1.08 × $10^{7}$ kg/yr

Explanation:

• The rate r at which the coal is been burnt is 8.02 kg/s.

• Amount of sulphur in the burning coal is given as 4.40 %

i.e., 4.4/100 × 8.02 = 0.353 kg/s. Which is equivalent to the rate at which the sulphur is been burnt.

• Since the burning of sulphur oxidizes it to produce SO2, it follows that the non-oxidized portion of the sulphur will go with the bottom ash.

• The bottom ash is said to contain 2.80 % of the input sulphur.

• Hence the portion of the SO2 produced is 100 — 2.80 = 97.20 %.

• The rate of the SO2 produced is percentage of SO2 × rate at high sulphur is been burnt.

  = 97.20/100 × 0.353 kg/s.

  = 0.343 kg/s.

• To get the annual emission rate of SO2, we convert the kg/s into kg/yr.

1 kg/s = 1 kg/s × (60 × 60 × 24 × 365) s/yr

1 kg/s = 31536000 kg/yr

• Therefore, 0.343 kg/s = 0.343 × 31536000 kg/yr

     = 10816848 kg/yr

     = 1.08 × 10^7 kg/yryr.