1. 1.6 Fundamental Calculations 1.6.1. Mass Balance In steady state flow, the total mass of material entering a reactor must equal to total mass leaving the reactor

2. Example 1.3 Pulverized coal-fired steam boiler A large pulverized, coal-fired steam boiler generates steam to generate electricity. Compute the total mass of material entering and leaving the boiler. Input: - 455 tons coal/h (114.8 kg/s) - coal assay (by mass): 2.1% sulfur 8% ash - 30% excess air Output: SO2, CO2, N2, O2, flyash in stack gas and bottom ash from boiler Assumption: - all the sulfur and carbon are converted to SO2 and CO2 - 18% of ash leaves as fly ash and 82% leaves as bottom ash

3. –See notes for detailed calculations Pulverized Coal-fired Steam boiler 455 tons coal /h (114.8 kg/sec) 2.1% Sulfur 8% ash SO2 CO2 N2 O2 Flyash in stack Bottom ash in boiler Electricity

4. Summary Pulverized Coal-fired Steam boiler 455 tons coal /h (114.8 kg/sec) 2.1% Sulfur 8% ash SO2 CO2 N2 O2 Flyash in stack Bottom ash in boiler Electricity Carbon: 103.2 kg C/sec Sulfur: 2.4096 kg S/sec Ash: 9.184 kg ash/sec Oxygen: 360.89248 kg O2/sec Nitrogen: 1177.1365 kg N2/sec Total: 1652 kg/sec CO2: 378.4 kg CO2/sec SO2: 4.8192 kg SO2/sec Bottom ash: 7.5309 kg/sec Fly ash in stack: 1.6531 kg/sec Oxygen: 83.2832 kg O2/sec Nitrogen: 1177.1365 kg N2/sec Total: 1652 kg/sec

6. The plant produces approximately 13,000 tons of coke per day, along with more than 225 million cubic feet of coke oven gas. Clairton Works is the largest coke producing facility in the United States, supplying blast furnace coke for iron and steel production for the commercial coke market, the Mon Valley Works and other U. S. Steel facilities