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BOILER INJECTION, WET- LIMESTONE PROCESS DESCRIPTION The plant to be described i

ID: 1061127 • Letter: B

Question

BOILER INJECTION, WET- LIMESTONE PROCESS DESCRIPTION The plant to be described is to produce 500 MW of electrical power. The flow rates, compositions, stream conditions, and other details to be given are representative of such installations. The key step in removing from the stack gas is the reaction of with Cao and oxygen to produce, an insoluble stable compound. Four major components of the process will be traced: the coal-limestone-stack gas streams, the scrubber water, the cooling-heating water cycle, and the generated steam cycle. The composition of coal can vary considerably, but that shown in Table CS 2.1 is typical of that used in this process. During coal combustion the sulfur in the coal reacts to form and very small amounts of Eighty-five percent of the ash in the coal leaves the boiler in the stack gas as fly ash; nitrogen emerges as N2, and the carbon, hydrogen, and sulfur in the fuel are oxidized completely to H20, and Table cs 2.1Coal Properties 1 Composition (ultimate analysis) Dry Wt% Component Ash 7.2 Sulfur 3.5 Hydrogen 5.0 Carbon 75.2 Nitrogen 1.6 oxygen 7.5

Explanation / Answer

Answer:

CS 2.1 attached with this solution

Basis Coal 100 lb/min

CS 2.2

Sulphur 0.11 mole/sec

Hydrogen 5 mole/sec

Carbon 6.27 mole/sec

Nitrogen 0.11 mole/sec

Oxygen 0.47 mole/sec

CS 2.3 oxygen feed rate 7.5 lb/min.

CS 2.4

(a) 10.5 lb/min

(b) 0.17 SCF/min

CS 2.5 7.2 lb/min

CS 2.6 gas leaves at the rate of 15 lb/min and waste removal rate is 15%

CS 2.7 13,000 btu/lb

CS 2.8

(a) 1.67 lbmole/min

(b) 0.027 SCF/min

CS 2.9 5% additional coal is required

CS 2.10 100 lb/hr is the feed rate of liquid to each scrubber