Investigation of Process and System Design Variables for Catathermal Combustion of Low Btu Gas

Abstract

A laboratory scale experimental program was conducted* to determine design criteria for specification of catalyst configurations for “catalytically supported thermal combustion” of low Btu gas. The range of experimental parameters was chosen to simulate gas turbine combustor operation. Flashback-free operation was demonstrated for premixed combustor feed to a CATCOM* catalyst over the entire range of an anticipated commercial cycle. The effect of inlet gas compositional variables on combustion efficiency was defined. The trade-off between combustion efficiency and pressure loss was evaluated by testing five catalyst configurations having different catalyst volumes and geometric properties. A prototype catalyst configuration was selected, and a parametric performance map was developed showing the effect of low Btu gas composition, heating value, operating temperature and pressure, and reference velocity. No effect of low Btu gas heating value on combustion efficiency was observed over the range of 4.5 to 6.75 MJ/m3 (120 to 180 Btu/ft3). A lower inlet temperature which ensures combustion efficiency>percent at 30.5 m/s was 200 C. An inlet temperature of 150 C was sufficient to maintain combustion efficiency>99 percent at 15 m/s. Pressure loss for the preferred configuration was as low as 3.5 percent, even at 30.5 m/s reference velocity.