Question
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We want to reduce the refinery’s carbon footprint, starting with SMR. What's the best economic approach: CCUS, an alternative process, or buy in the hydrogen?
Nov-2021
Answers
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Beth Carter, Honeywell UOP, Beth.Carter@Honeywell.com
The steam methane reformer (SMR) is often the largest single source of CO2 emissions in a refinery. Fortunately, approximately 60% of the CO2 produced during hydrogen production is available in a contaminant-free stream with a high partial pressure of CO2, which makes the cost of carbon capture often the lowest among all the available streams in a refinery. Being both the largest source and the source with the lowest cost of carbon capture, the SMR is a prime unit to evaluate for reducing a refinery’s carbon footprint.
Several technologies are commercially available for retrofitting an existing SMR with carbon capture, including solvent processes, pressure swing adsorption (PSA) systems, membrane systems, and cryogenic processes. Optimised combinations of these technologies can significantly reduce the cost of carbon capture. The choice of carbon capture technology depends on the value of extra H2 recovery and ultra-high CO2 recovery; the required product specifications for H2 and CO2; and the availability, cost, and carbon intensity of power versus steam. Honeywell UOP’s CO2 Fractionation System for carbon capture from an SMR provides 10-20% extra H2 yield and 99+% CO2 recovery from the existing PSA tail gas in a completely power-driven process (no steam required), with a smaller required footprint compared to a solvent carbon capture system. The cost of carbon capture can typically be $20-40/t CO2, which includes operating costs, fixed costs, and annualised capital costs for the carbon capture equipment plus a credit for the additional hydrogen recovered. Financial incentives in the form of carbon tax or carbon credits exist today in many parts of the world at values higher than this, making SMR retrofit not only a technically viable option, but also a commercially viable option for starting the CO2 countdown.
Nov-2021
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