Synergistic material and process development: Application of a metal-organic framework, Cu-TDPAT, in single-cycle hydrogen purification and CO2 capture from synthesis gas

Abstract

We employ a synergistic material and process development strategy to improve the performance of a single-cycle vacuum pressure swing adsorption (VPSA) process for the hydrogen purification and the CO 2 separation from reforming-based hydrogen synthesis. Based on process-informed adsorbent selection criteria, including high CO 2 cyclic capacity and selective uptake of impurities like CO, N 2 , and CH 4 over H 2 , a metal organic framework (MOF), Cu-TDPAT, is selected. First, adsorption isotherms of CO 2 , CO, CH 4 , N 2 and H 2 are measured. Subsequently, a column model is used for optimization-based analysis of the VPSA cycle with Cu-TDPAT as the adsorbent to assess both the separation performance, and the process performance in terms of energy consumption and productivity. The adsorption characteristics of Cu-TDPAT require an adaptation of the original VPSA process to increase the CO 2 separation performance of the process. After this adaptation, Cu-TDPAT clearly outperforms the benchmark material, zeolite 13X, in several metrics including higher H 2 purities and recoveries and fewer columns needed for a continuous separation process. Most importantly, Cu-TDPAT offers a two-fold improvement in CO 2 productivities when compared to zeolite 13X, thus substantially decreasing the bed size required to achieve the same throughput. However, zeolite 13X remains the better adsorbent for reaching high CO 2 purities and recoveries due to its higher selectivity for CO 2 over all other components in the gas stream, which leads to an overall lower energy consumption. The obtained results show that the final performance strongly depends on an interplay of various factors related to both material and process. Hence, an integrated process and material design approach should be the new paradigm for developing novel gas separation processes.

Engineering metal–organic frameworks for adsorption-based gas separations: from process to atomic scale

“…One way to answer this question is to perform a screening study, the overall approach of which is described in Figure 4 and below. 56,121,122,51,54,55 Screening studies aim to identify the best process conditions for an adsorbent and to derive a ranking of {sorbent + process} systems for a given separation, considering one or more process cycles. These studies can rely on databases of existing or hypothetical sorbents whose sorption isotherms can be simulated (e.g.…”

“…In recent years, there has been, however, an increasing number of studies focusing on large scale process simulation, which aim to screen existing MOFs to identify the most promising ones, based on engineering-centred criteria. [43][44][45][46][47][48][49][50][51][52][53][54][55] In addition, recent reports have adopted an inverse engineering approach and have started to highlight desirable material features -albeit at a rather high level -that are driven by process modelling. 48,50,[56][57][58] A successful adsorption-based gas separation application depends on the identification of the most appropriate sorbent/process combination, which demands that the engineer and the chemist have an understanding of each other's work.…”

Perspective on the hydrogen economy as a pathway to reach net-zero CO2emissions in Europe

“…Development of novel separation processes. Two concepts alternative to liquid scrubbing are particularly promising: (i) the use of adsorption cycles at ambient temperature to carry out the CO 2 and H 2 separations in one single process using a vacuum pressure swing adsorption (VPSA) cycle, [171][172][173] and (ii) the use of membranes to separate hydrogen from a pressurized syngas with low energy consumption. The former is of particular interest for small to medium size applications and for retrofitting existing PSA; future R&D efforts should focus on demonstrating the technology at relevant scale and in real industrial conditions.…”

Metal–Organic Framework Membranes: Advances, Fabrication, and Applications

“…[ 1 ] This class of materials not only has a highly tunable and regular pore structure, variable functionality, and internal connectivity, [ 2 ] but the superior designability enables them to accommodate the introduction of a variety of functional sites on frames, cavities, and channels. [ 3 ] These make them have important applications in many fields, including drug delivery, [ 4 ] adsorption, [ 5 ] antimicrobials, [ 6 ] electron conduction, [ 7 ] gas storage, [ 8 ] catalysis, [ 9 ] sensing, [ 10 ] and energy conversion. [ 11 ] MOFs were first developed by Hoskins and Robson via connecting discrete metal clusters and reappraising the Zn(CN) 2 and Cd(CN) 2 structure [ 12 ] and then termed MOFs in 1995.…”