Catalytic combustion process

Abstract

A combustion process, e.g. for a gas turbine, comprises catalytically combusting part of a fuel/air feed in a preliminary catalyst body which has through passages and supports, or is composed of, a catalyst active for the combustion of the fuel. The resultant heated gas stream is then mixed with the remainder of the feed, and that mixture is combusted, e.g. catalytically in a main catalyst body. The amount of combustion occurring in the preliminary catalyst body is sufficient that combustion of the mixture of the heated gas stream and the remainder of the feed can be sustained at the desired operating conditions. Under those desired operating conditions combustion of the feed could not be sustained in the absence of the heating given by the combustion in the preliminary catalyst body. There may be more than one preliminary catalyst body. The preliminary catalyst body or bodies may also be provided with passages wherein combustion does not take place under the desired operating conditions so that those passages act as a bypass. Preferably the combustion passages of at least the first preliminary catalyst body are of such size, that at the normal operating conditions, the flow therethrough is laminar, whereas the flow through the passages of the main catalyst body, where employed, is turbulent.