watergas

Water gas is a synthesis gas produced by reacting steam with hot carbon, such as coke or charcoal. The primary reaction is C + H2O → CO + H2, which yields a mixture rich in carbon monoxide and hydrogen at high temperatures (typically about 900–1200°C). In practice, the gas also contains smaller amounts of carbon dioxide, methane, nitrogen, and other impurities depending on the feedstock and operating conditions.

Historically, water gas played a major role in gas lighting during the 19th century. Raw water gas was often purified and then used as fuel for lighting or heating. Because of its significant carbon monoxide content, it posed safety risks and required cleaning and dilution before use. Over time, water gas was largely supplanted by town gas (coal gas) and, later, natural gas, but it remained important as a source of hydrogen and carbon monoxide for chemical synthesis.

Processing and applications: To tailor the gas for various uses, it could be treated to remove tar, sulfur compounds, and particulates. A complementary step, the water-gas shift reaction (CO + H2O → CO2 + H2), converts CO and steam into additional hydrogen and carbon dioxide, enabling adjustment of the hydrogen-to-CO ratio for specific chemical syntheses. Water gas is also a historical feedstock for producing syngas used in methanol, ammonia, and various hydrocarbon processing pathways.

Safety: The presence of carbon monoxide makes water gas highly toxic and potentially dangerous if vented or leaked. Modern processes typically use more controlled methods to generate and handle syngas.