CO2, NOx and SO2 emissions from the combustion of coal with high oxygen concentration gases

✍ Scribed by Y Hu; S Naito; N Kobayashi; M Hasatani

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 336 KB
• Volume: 79
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/s0016-2361(00)00047-8

✦ Synopsis

The emissions of CO 2 , NO x and SO 2 from the combustion of a high-volatile coal with N 2 -and CO 2 -based, high O 2 concentration (20, 50, 80, 100%) inlet gases were investigated in an electrically heated up-flow-tube furnace at elevated gas temperatures (1123-1573 K). The fuel equivalence ratio, f, was varied in the range of 0.4-1.6. Results showed that CO 2 concentrations in flue gas were higher than 95% for the processes with O 2 and CO 2 -based inlet gases. NO x emissions increased with f under fuel-lean conditions, then declined dramatically after f 0:8; and the peak values increased from about 1000 ppm for the air combustion process and 500 ppm for the O 2 (20%) ϩ CO 2 (80%) inlet gas process to about 4500 ppm for the oxygen combustion process. When f Ͼ 1:4 the emissions decreased to the same level for different O 2 concentration inlet gas processes. On the other hand, NO x emission indexes decreased monotonically with f under both fuel-lean and fuelrich combustion. SO 2 emissions increased with f under fuel-lean conditions, then declined slightly after f Ͼ 1:2: Temperature has a large effect on the NO x emission. Peak values of the NO x emission increased by 50-70% for the N 2 -based inlet gas processes and by 30-50% for the CO 2 -based inlet gas process from 1123 to 1573 K. However, there was only a small effect of temperature on the SO 2 emission.