Low Nox Combustion Concepts for Advanced Power Generation Systems Firing Low-Btu Gas.

摘要

The report gives results of an analysis of several advanced power generating concepts firing low-Btu gasified coal. A combined gas-turbine/steam-cycle power plant with integrated gasifier was the most promising from fuel utilization and economic viewpoints. Two representative combined cycle systems were chosen for detailed NOx emission and analysis:an advanced-technology high-temperature gas turbine with a waste heat boiler;and a supercharged boiler with a current-technology gas turbine. NOx emissions were investigated using a kinetic model,which was validated by comparison with best available experimental data and then applied to idealized combustor configurations. Calculations indicate that staged combustion involving rich primary zones and controlled mixing secondary zones minimizes thermal NOx and NOx produced from ammonia in the fuel gas. Minimum calculated NOx levels were: 150ppm for the high temperature turbine,with a 0.45equivalence ratio and 4000ppm of fuel ammonia;and 125ppm for the supercharged boiler,with 5% excess air and 500ppm of fuel ammonia. These results need to be verified experimentally,but they show the potential for achieving NOx emissions within the Federal NSPS without requiring ammonia removal from the fuel gas.