The carbon oxides are removed before use by means of pressure swing adsorption (PSA) with molecular sieves for the final purification.
Autothermal reforming (ATR) uses oxygen and carbon dioxide or steam in a reaction with methane to form syngas.
It occurs when a substoichiometric fuel-air mixture is partially combusted in a reformer, creating a hydrogen-rich syngas which can then be put to further use.
The capital cost of steam reforming plants is prohibitive for small to medium size applications because the technology does not scale down well.
However, analyses have shown that even though it is more costly to construct, a well-designed SMR can produce hydrogen more cost-effectively than an ATR for smaller applications.