Publication: The performance of non-adiabatic plate pressure swing adsorption for hydrogen purification from synthetic gas using organic adsorbents
Loading...
Date
2023-05-01
Authors
Hind Jihad Kadhim Shabbani
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Environmental and economic concerns related to the rising CO2 emissions have prompted ongoing research to seek for more environmentally friendly energy sources. Hydrogen (H2) has been considered as a prominent candidate for an alternative energy source in the past few decades. Hydrogen can be produced from fossil fuels through coal gasification or steam methane reforming (SMR). Natural gas or bio-methane from biogas reforming can also be used to produce hydrogen from SMR, as it is considered as one of the most economical routes for H2 production. H2 generated through this method, however, is accompanied by a great amount of CO2, which needs for the subsequent purification step. Pressure swing adsorption (PSA) can be used for H2 purification because it provides high efficiency in capturing CO2 with low operational costs.
This research investigates the performance of a novel non-adiabatic plate PSA (NAPSA) in improving the purity and recovery of the H2 product stream using two types of organic materials, namely spent coffee grounds (KSC) and palm kernel shells (PKS). Utilizing NAPSA mediated by KSC, the highest hydrogen purity and recovery of 99.99 % and 74.83%, respectively, were obtained. Comparison between the conventional adiabatic cylindrical column and NAPSA showed that the latter performed better H2 separation attributed to its better heat dissipation and better mass transfer with hydrogen and carbon dioxide diffusivity of 0.51 min-1 and 0.81 min-1, respectively. According to the results of the Aspen simulation, for H2 feed concentrations of 70, 80, and 90%, respectively, the hydrogen recovery increased while switching from CNACA to NAPSA plate columns from 18.63 to 50.29, 14.65 to 33.54, and 15.47 to 39.12%. For 1 min or shortened adsorption times, this effect is more pronounced. This outcome is consistent with the experimental study comparing CACA and NAPSA mediated by PKS and KSC samples. NAPSA significantly increased the purity of the generated H2, most notably at 80% H2 feed and 3 minutes of adsorption time at 95.55% using NAPSA mediated by KSC as opposed to 90.98 and 91.02% for CNACA and CACA, respectively. The longer CO2 retention time and better heat transfer management are important in resolving the inherent trade-off issue between the purity and recovery of the gas purification system. Despite the difference in the recovery, both KSC and PKS yielded high hydrogen purity of 99.99% from NAPSA, attributed to the favourable characteristics of the adsorbents