Water gas

Water gas is produced from synthesis gas, which is composed of carbon monoxide and hydrogen. Syngas is a useful product, but requires careful handling due to its flammability and the risk of carbon monoxide poisoning. The water-gas shift reaction can be used to reduce the carbon monoxide while producing additional hydrogen, resulting in water gas.

Syngas is made by passing steam over a red-hot carbon fuel such as coke:

The reaction is endothermic, so the fuel must be continually re-heated to keep the reaction going. In order to do this, an air stream, which alternates with the vapor stream, is introduced for the combustion of carbon to take place.

Theoretically, to make 6 L of water gas, 5 L of air is required.

Or, alternatively, to prevent contamination with nitrogen, energy can be provided by using pure oxygen to burn carbon into carbon monoxide.

In this case 1 L of oxygen will create 5.3 L of pure water gas.

The water-gas shift reaction was discovered by Italian physicist Felice Fontana in 1780.

Water gas was made in England from 1828 by blowing steam through white-hot coke.

In 1873, Thaddeus S. C. Lowe developed and patented the water gas process by which large amounts of hydrogen gas could be generated for residential and commercial use in heating and lighting. This gas provided a more efficient heating fuel than the common coal gas, or coke gas, which was used in municipal service. The process used the water-gas shift reaction:

The process was discovered by passing high-pressure steam over hot coal, the major source of coke gas. Lowe's process improved upon the chimney systems by which the coal could remain superheated, thereby maintaining a consistently high supply of the gas. The reaction produced carbon dioxide and hydrogen, which, after a process of cooling and "scrubbing", produced hydrogen gas.

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