Publisher Summary Pollutant gases from industries are usually either discharged to the atmosphere or partially purified to remove harmful impurities since it is difficult to use some of these gases as furnace fuels when their calorific values are very low. If these gases are fired in conventional boilers, several problems arise: a low calorific value leads to low flame temperature, slow reactions in the furnace, high volume of combustion products, and flue gases with low emissivity. Hence, supplementary equipment is necessary which may cost a lot more than the energy gained. So far, development has concentrated on heat extraction using two adiabatic reactors connected together with a heat exchanger placed between them. In this kind of process, it is difficult t o control run-away. Therefore, we have improved the technique of handling low concentration gas by integrating a fixed-bed reactor with a heat exchanger for removing heat from the system. The system can be used to remove low concentrations of CO and hydrocarbons.