Other Gaseous Feedstocks
Refinery Gas. Refinery gas has been used as a feedstock for partial oxidation. Although partial oxidation cannot usually compete with steam reforming for hydrogen production from natural gas, the situation can be different with a refinery gas feed. Refinery waste gas streams can contain considerable quantities of olefins, which would need to be hydrogenated upstream of a steam reformer. The partial oxidation route is not sensitive to the presence of unsaturates in the feed, and this flexibility can provide opportunities (Ramprasad etal. 1999).
Attention needs to be paid to the issues of metal dusting and methanation as with natural gas, but if there is no sulfur in the feed, then other solutions are possible, such as using a quench reactor if hydrogen is to be the end product.
FT Off-Gas. Fischer-Tropsch off-gas is essentially similar to many refinery off-gas streams in that it can contain significant quantities of unsaturated hydrocarbons. The same considerations apply. Where the main syngas generation for the FT synthesis is partial oxidation of natural gas, one only needs to be careful with the recycle of inerts (Higman 1990). This is, however, a limitation imposed by the synthesis process and not by the partial oxidation itself.
Coke Oven Gas. There are two recorded plants using coke oven gas as a feedstock. Coke oven gas is available only at low pressure. This makes the economics unfavorable in all but the most exceptional cases.