Abstract: A gas combustion plant or apparatus comprising a combustion chamber, a burner for introducing the gas to the combustion chamber and a tubular heat exchanger for preheating the gas to be combusted, by heat exchange with the hot combustion gases. The burner and the tubular heat exchanger are combined in that the straight, parallel tubes are provided in a uniformly distributed pattern over the cross-section of one end portion of the combustion chamber. The end of the tubes adjacent the end of the combustion chamber are connected to an inlet for the gas to be combusted, which are accordingly introduced into the combustion chamber through the tubes at a high velocity creating a desired turbulence in the portion of the combustion chamber in front of the tube orifices.