Q697. How should fuels and feedstocks be reported for hydrogen production process units?

A697. Per 40 CFR 98.163, fuels and feedstocks should be reported for each hydrogen production process unit. If a facility used both natural gas and refinery fuel gas to produce hydrogen in a single process unit, there should be one unit reported with two fuels and feedstocks, not two separate hydrogen production process units with one fuel and feedstock each. As noted in FAQ 696, process heaters used to supply heat needed for the SMR reaction are considered part of the hydrogen production process unit. If refinery fuel gas is used for the process heater and natural gas is used as the feedstock, and emissions are vented from a common stack, there should be one hydrogen production process unit reported with two fuels and feedstocks. For the purposes of the material balance approach in 40 CFR 98.163(b), recycled streams should not be considered fuel or feedstocks as the carbon in these recycled streams has already been accounted for in Equations P-1, P-2, or P-3, which account for all carbon in the direct (non-recycled) fuels and feedstocks. For example, PSA off-gas recycled to the SMR furnace should not be considered as a separate feedstock because the carbon in this gas stream has already been accounted for in the direct feedstock streams.