This article presents a summary of some experimental results obtained on a 1.4 MW CHP engine. Tests concern the effect of H2 and CO addition to the natural gas at the engine inlet. Hydrogen and CO were obtained through the partial oxidation of methane.
A honey-comb Platinum based catalyst was used for the partial oxidisation of methane. Part of the natural gas main stream was deviated and mixed with air to supply the catalyst. Catalyst output (mixture of H2, CO, H2O, CO2, N2 and methane) are then mixed with the main stream of natural gas supplying the engine.
Two different tests were conducted, the first one is an operation under a constant average combustion chamber temperature and the other one is an operation at a constant NOX level in the exhaust gases.
Results showed a decrease of about 10% in NOX emissions when operating under constant combustion chamber temperature (this temperature is the average temperature of the four strokes inside the cylinders); and a slight increase of engine efficiency for a constant NOX emissions level.