Abstract: A method and a device for increasing the temperature of an exhaust gas or process gas with an oxidizable share, in particular a carbon monoxide-containing nitrogen oxide flue gas, before a catalytic flue gas denitrification is performed, wherein an exhaust gas or flue gas duct is in communication with at least one hot gas duct designed as a combustion chamber which hot gas duct is assigned with a combustion device, so that the oxidizable share, in particular the carbon monoxide share, of the exhaust gas or flue gas conducted through the hot gas duct is oxidized at least partially in particular to carbon dioxide.