Plant used to produce synthesis gas, a mixture of carbon monoxide (CO) and hydrogen (H₂). The process uses light hydrocarbons in preference, such as natural gas, which are mixed with hot steam via a catalyst and converted into CO and H₂. The next stage of the process involves the conversion of the CO to carbon dioxide (CO₂) using steam, which enables additional hydrogen to be recovered. This gas mixture is then purified, with the CO₂ and other unwanted parts of the mixture being removed.