Natural Gas Reforming (or Steam Mehtane Reforming) is a chemical reaction used to generate syngas (H2 and CO) from hydrocarbons such as natural gas. This is completed in a reformer which reacts methane with steam at high temperature and pressure along with nickel catalyst. Steam methane reformer is extensively used in industry to produce hydrogen.

A pretreatment system consists of compression and desulphurization (i.e. sulfur removal) and decarbonization ( i.e. CO2 removal), which is used to recover the methane in the biogas. A primary desulphurization unit is applied to remove the sulfur. Then, a set of the compressor (s) is employed to boost the biogas to a pressure which is desirable for the downstream decarbonization unit. Before the biogas enters into the decarbonization unit, a secondary desulphurization unit is used to further reduce the sulfur.

The decarbonized gas, called as BIOMETHANE, enters a reforming system, where the biomethane converts into syngas that is composed of hydrogen (H₂) and carbon dioxide (CO₂) and carbon monoxide (CO) and methane (CH₄) and etc..

A PSA unit is deployed to separate hydrogen from syngas. The off-gas of the PSA is recovered as the fuel for the reforming system, as the off-gas entrains significant methane.