An excess of very sour fuel gas can be the result when a refinery process heavy feedstocks into modern low-sulfur fuels. But refiners can in fact turn a profit from the additional fuel gas and even reduce sulfur emissions with fuel gas hydrotreatment.
Many refineries (will) experience an excess of very sour fuel gas as they apply more severe processing to produce low-sulfur fuels that comply with new standards. One obvious example is the upcoming MARPOL regulations that encourage refiners to produce marine fuels with much less sulfur than conventional bunker fuel.
Excess fuel gas is often flared or used for low-value applications such as power generation. But refiners can make a better deal for themselves – and for the environment.
Using Fuel Gas Hydrotreatment (FGH™), the fuel gas can be purified into a clean feedstock that can be used for the refinery’s catalytic hydrogen production. To produce more low-sulfur fuels, refiners need more hydrogen, so the cheaper feedstock for the hydrogen unit comes in handy. The purified fuel gas can also serve as support fuel for Claus sulfur units and other natural gas-consuming units.
FGH™ address both the environmental and gas value aspects in a single unit, which can be inserted into the current fuel gas system, re-using the amine wash. In addition, FGH™ can increase hydrogen production.
Fuel gas contains not only H2S but also other sulfur species that are hard to remove in the amine wash, such as mercaptans, COS, thiophenes, and di-sulfides. Upstream FGH™ converts all these hard-to-remove sulfur species to H2S that can be effectively eliminated in the existing amine wash. The product from a FGH™ unit is saturated (no di-olefins or olefins), which virtually eliminates the risk of coking, fouling and corrosion.
The FGH™ technology is commercially proven at large scale, and the investment is typically returned in one year.