Vesikaasun

Vesikaasun, also known as water gas, is a combustible gas mixture produced by reacting steam with hot carbon-rich material such as coke or coal in a limited-oxygen environment. Its main constituents are hydrogen and carbon monoxide, with smaller amounts of carbon dioxide and methane depending on process conditions.

Production and chemistry

Water gas is created through endothermic reactions where steam reacts with hot carbon: C + H2O → CO + H2. The resulting gas mixture can be adjusted by subsequent water-gas shift reactions, CO + H2O → CO2 + H2, which increase the hydrogen content of the gas. Typical compositions vary but often contain substantial proportions of CO and H2, with CO2 and trace amounts of other hydrocarbons.

History and applications

In the 19th and early 20th centuries vesikaasun was a major source of lighting and heating in urban gas networks before the widespread use of natural gas and modern town gas blends. It was also used as a chemical feedstock and as a component of synthesis gas (syngas) for various chemical processes. With the advent of natural gas and more efficient reforming methods, the production of vesikaasun declined for urban lighting, though its underlying chemistry remains relevant for processes that generate syngas for methanol, ammonia, and other chemicals.

Safety and handling

Vesikaasun contains carbon monoxide, which is highly toxic, and poses fire and explosion risks when mixed with air. Proper containment, purification, and gas handling procedures are essential. The gas is not typically stored in bulk and is usually produced on demand for industrial processes.

See also

Synthesis gas (syngas), town gas, water-gas shift reaction.