TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The outlet of the compressor is connected to the inlet of a methanization installation. The outlet of the compressor is connected to the inlet of a gas turbine. The system further comprises: a tar removing installation that is fitted with an inlet connected to the outlet opening of the reactor installation, and with an outlet connected to the inlet opening of the reactor; and an eliminating installation for the removal of sulfur and/or chlorine, which is fitted with an inlet connected to the outlet opening of the reactor installation and with an outlet connected to the inlet opening of the reactor. The inlet of the eliminating installation for the removal of sulfur and/or chlorine is connected to the outlet of the tar-removing installation.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The higher hydrocarbons present in the combustible gas comprise unsaturated hydrocarbons such as acetylene and ethylene, saturated hydrocarbons such as ethane, and aromatic hydrocarbons such as benzene and toluene. Preferred Process: The combustible gas is methanized after the pressure of the combustible gas is increased by the compressor. After the pressure of the combustible gas is raised by the compressor, the combustible gas is used in a downstream utilization e.g. it is burned in a gas turbine. The step (a)-(c) are carried out at a pressure that is lower than 5 bar, preferably 1-2 bar. The compressor raises the pressure of the combustible gas to at least 5 bar, preferably at least 10 bar. In step (c), at least 70% of the H2O and CO2 present in the combustible gas are removed. The removal of the H2O from the combustible gas includes cooling to a temperature at which the H2O present in the combustible gas condenses out, forming a condensate. The removal of the CO2 from the combustible gas comprises chemical absorption of CO2. The combustible gas is introduced into an absorber installation, in which the combustible gas is brought into contact with an absorbent for CO2, such as amine. The step (b) is carried out with the aid of a catalyst of which the active component comprises at least one of the noble metals of platinum, palladium, rhodium, ruthenium, (osmium, iridium) and/or at least one of the transition metals of nickel, cobalt, molybdenum and/or tungsten. A quantity of tar, sulfur and/of chlorine are removed from the combustible gas prior to step (b). EXAMPLE - No suitable example given.