Ammonia and its control in clean coal technology systems
- Univ. of Leeds (United Kingdom). Dept. of Fuel and Energy
The formation of NH{sub 3} and HCN within clean coal technology systems can lead to increased gas turbine emissions of NO{sub x} if steps are not take to remove these fuel-N compounds from the fuel gas. The gas cleaning system utilized is dependent upon the type of gasification system. Where the fuel gas is cooled prior to combustion, conventional clean-up methods are adopted and have been proven both effective and economic. By cleaning the gases at higher temperatures, (400--900 K), higher overall cycle efficiencies can be obtained though these require alternative clean-up processes. The nitrogen chemistry leading to NH{sub 3} formation within these systems is different to that occurring in conventional combustion systems, and it is of considerable interest to know the mechanism of NH{sub 3} production. Work has concentrated on the Air Blown Gasification Cycle (ABGC), (formerly Topping Cycle). Initial studies have shown that nitrogen released form the volatiles together with some char nitrogen, may be oxidized to NO in the spouted section of the pressurized gasifier. Subsequent destruction of this occurs within the bed and freeboard region resulting in the main gaseous nitrogen species being N{sub 2}, and some NH{sub 3} and HCN. Predictions illustrate that HCN and NH{sub 3} concentrations are in supra-equilibrium and may be formed through the reduction of NO. The final levels of NH{sub 3} formed within the fuel gas are however, strongly dependent upon the kinetic data utilized and at lower temperatures, deviation from Arrhenius behavior for certain intermediate reactions can result in marked differences on the final predicted NH{sub 3} concentration in the fuel gas.
- OSTI ID:
- 257029
- Report Number(s):
- CONF-950952-; TRN: IM9631%%235
- Resource Relation:
- Conference: 12. annual international Pittsburgh coal conference, Pittsburgh, PA (United States), 11-15 Sep 1995; Other Information: PBD: 1995; Related Information: Is Part Of Twelfth annual international Pittsburgh coal conference: Proceedings. Coal -- Energy and the environment; Chiang, S.H. [ed.]; PB: 1248 p.
- Country of Publication:
- United States
- Language:
- English
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