CATALYTIC COMBUSTION GAS-TURBINE SYSTEMS - THE PREFERRED TECHNOLOGY FOR LOW EMISSIONS ELECTRIC-POWER PRODUCTION AND COGENERATION

The operating requirements for practical catalytic combustion systems are presented. Catalytic materials for methane combustion are then rev iewed in light of these operating requirements. Measured catalytic rat es for methane oxidization for a number of active metal and oxide cata lyst systems are reported and compared. The precious metals, particula rly Pd, are most active. The oxides can exhibit high surface areas but in all cases have a much lower areal activity resulting in a substant ially lower weight specific activity. Data on the thermal stability an d volatility of both support and active components are presented and d iscussed in terms of the required operating temperatures, Tt is conclu ded that at the required operating temperature for modem gas turbines, most catalyst systems would not have sufficient stability and life. A n alternative approach is to limit the catalyst temperature and to rea ct a portion of the fuel after the catalyst. This process has substant ial advantages. This latter system will be described and the important catalyst performance characteristics discussed. Test results demonstr ate NO, levels below 2 ppm even at combustor outlet temperatures as hi gh as 1500 degrees C.