[1][2] A membrane reactor is a device where oxygen separation, steam reforming and POX is combined in a single step.
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, for example in a fuel cell.
The capital cost of methane reformer plants is prohibitive for small to medium size applications because the technology does not scale down well.
Conventional steam reforming plants operate at pressures between 200 and 600 psi with outlet temperatures in the range of 815 to 925 °C.
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.