Question
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With the chemical value of hydrogen (H₂) increasing, what are the best options for extracting H₂ from fuel gas?
Jan-2024
Answers
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Neeraj Tiwari, Honeywell UOP, Neeraj.Tiwari@Honeywell.com
High-yield byproducts generated by the refinery process for motor fuel, diesel or aromatics production can be high-value secondary revenue. The typical composition of fuel gas contains H2 as ~30-50 mol%, and other major components are LPG range material. To monetise the benefit of these high-value byproducts and increase the overall profitability, a novel concept involving a dual sponge absorber can be applied to the off-gas stream (routed to fuel gas header) to recover the majority of LPG range material along with light naphtha, if any.
The application of a novel dual sponge absorber will improve the hydrogen composition in off-gases to a high level (such as 70-85 mol%). This high-purity gas can then be routed to PSA to recover hydrogen efficiently having a purity of 99.9 mol%. In catalytic reforming, secondary byproducts generated include H₂, LPG, and fuel gas. Of these byproducts, the lowest value byproduct is generally fuel gas.UOP’s proprietary RecoveryMax system allows 95% recovery of hydrogen, >85% LPG recovery, and nearly 100% reformate recovery by purifying more of these byproducts and not diverting them to fuel gas. Alternative options are being explored based on where hydrogen is being used as one of the raw materials.
One option is to contact the feed stream or any hydrocarbon stream with hydrogen-rich fuel gas that will absorb the hydrogen; then, the absorbed hydrogen can be used during the reaction process.Concern with this option is that it can also absorb impurities from fuel gas (such as C1, C2), which may not be desirable in the process.
Jan-2024
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