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In CCR platformer high purity hydrogen is produced using PSA, PSA outlet tailgas contains 40-50% H2, flow is about 4-5 TPH and pressure 5-6 Kg/cm2g. Can we use this gas to recover further Hydrogen by PSA or membane separation processes? We have a spare PSA available. Can we feed low purity gas to PSA?
 
Answers
09/09/2015 A: Yogesh Bhintade, Raffinerie Heide, bhintadeyogesh@gmail.com
If you have a spare PSA, it can definitely be recovered, just check for the pressure requirement at PSA inlet. May be you need a compressor. AS PSA tail gas contains olefins , Another option you may consider is to send it to Steam cracker compressor to recover the olefins.
02/09/2015 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
PSA tail gas is normally at very low pressure. To try and recover additional H2, you would need a lot of compression to boost the gas back up to normal PSA operating pressure. Between the capital and operating costs of this compression capacity, I would be surprised if this is an economic option. Have you talked to UOP? There may be some ways to boost H2 recovery in the PSA that would be a lot more economic.