PSA H2 Purification

As with air separation the purification of hydrogen via a PSA process is also a well developed field. The market place is highly competitive and UOP competes with 

The contaminants in SMR that must be managed include GO2, GO, GH4, N2 and water. 

For ROG we mainly deal with H2 and hydrocarbons up to about a G6. In EOG we must clean up GH4 and GO2. The total list of all contaminants that must be handled also includes argon and some mercaptans. 

Unlike PSA air separation the adsorbents used in hydrogen purification are not limited to zeolite molecular sieves. Garbons and silica gel are used in many PSA installations. Zeolites are used for obtaining certain critical specifications where the nature of the isotherms that they possess helps in recovery, achieving purity and minimizing bed size factors. 

It has been mentioned that purity and recovery are very significant drivers for the business of hydrogen purification. Today PSA hydrogen purifiers can deliver purities of several nines 99.9% purity while simultaneously recovering nearly 90% of the hydrogen found in the feed gas. 

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Catalytic steam-methane reforming (SMR) is the popular commercial method of H2 production. Figure 7 shows a flow diagram of this route of H2 production consisting of a SMR reactor, a WGS reactor, a PSA H2 purification unit, and heat exchangers for heat recovery [20]. 

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