Design of a H₂ PSA for cogeneration of ultrapure hydrogen and power at an advanced integrated gasification combined cycle with pre-combustion capture

A novel hydrogen pressure swing adsorption system has been studied that is applied to an advanced integrated gasification combined cycle plant for cogenerating power and ultrapure hydrogen (99.99+ mol%) with CO₂ capture. In designing the H₂ PSA, it is essential to increase the recovery of ultrapure hydrogen product to its maximum since the power consumption for compressing the H₂ PSA tail gas up to the gas turbine operating pressure should be minimised to save the total auxiliary power consumption of the advanced IGCC plant. In this study, it is sought to increase the H₂ recovery by increasing the complexity of the PSA step configuration that enables a PSA cycle to have a lower feed flow to one column for adsorption and more pressure equalisation steps. As a result the H ₂ recovery reaches a maximum around 93 % with a Polybed H₂ PSA system having twelve columns and the step configuration contains simultaneous adsorption at three columns and four-stage pressure equalisation.