Coke-oven gas is a fuel gas having a medium calorific value that is produced during the manufacture of metallurgical coke by heating bituminous coal to temperatures of 900°C to 1000°C in a chamber from which air is excluded. The main constituents are, by volume, about 50% hydrogen, 30% methane and 3% higher hydrocarbons, 7% carbon monoxide, 3% carbon dioxide and 7% nitrogen. The gas has a heating value of about 20,000 kJ/m3.