The gasification of black liquor, followed by its use in gas turbine engines, is an emerging alternative to the direct firing of the liquor in Tomlinson recovery boilers. Many gasification systems, however, convert the fuel nitrogen present in the liquor into ammonia (NH3) in the fuel gas, which leads to unacceptable NOx emissions in gas turbine combustors.
This work uses detailed chemical kinetic modeling to examine the influence of two combustor modifications for the control of NOx emissions from black liquor fuel gas combustion. Availability analysis is also used to evaluate the influence of these NOx control choices on the thermodynamic architecture of the overall system. A rich-quench-lean configuration makes use of air staging. An alternative is to use a hot, rich external precombustor to remove NH3 before the main combustor. Here, the external, rich stage operates at around 30% theoretical air. Adiabatic temperatures are too low to obtain good NH3 reduction, so recuperative heating is necessary.
Gas Turbine Thermoelements Availability Analysis