Innovative steam methane reforming for coproducing CO‐free hydrogen and syngas in proton conducting membrane reactor

Abstract

Steam methane reforming (SMR) is a commercial process to produce syngas. Normally, the as-produced syngas is characterized by a H 2 /CO ratio of 3. However, such H 2 /CO ratio is unsuitable for Fischer-Tropsch synthesis. The hydrogen obtained by subsequent upgrading of syngas usually contains residual CO, which readily deactivates Pt electrocatalysts in fuel cells. Here we report an innovative route by coupling SMR with H 2 removal in a proton conducting membrane reactor to coproduce syngas with a preferable H 2 /CO ratio of 2 and CO-free H 2 on opposite sides of the membrane, which can be directly used for Fischer-Tropsch synthesis and fuel cells, respectively. Notably, H 2 is in-situ extracted by the membrane that only allows the permeation of H 2 as protons through the oxide lattice with infinite selectivity, and thus the obtained H 2 is CO-free. This work could provide an alternative option in one-step conversion of methane into two inherently separated valuable chemicals.

Targeting climate‐neutral hydrogen production: Integrating brown and blue pathways with green hydrogen infrastructure via a novel superstructure and simulation‐based life cycle optimization

“…Generally, methane is widely used in the reforming process due to the higher hydrogen to carbon ratio than other hydrocarbons 18 . Depending on the process operating conditions, a substantial amount of CO is expected after the reforming stage, so the outlet from the reformer goes into a series of water gas shift reactors to increase the consumption of produced CO and maximize the H 2 production 19 . Two water gas shift reactors, high‐temperature shift (HTS) and low‐temperature shift (LTS), operating at different temperatures, have been considered.…”

“…In this study, using the Aspen Plus flowsheet developed for the technology alternatives described, the operating conditions were varied to generate the LCI data to illustrate the effect of the operating conditions on the GWP for pathways in the superstructure. Necessary assumptions used in this study include: The operating conditions varied for the brown hydrogen processes are the temperature of the inlet feed (reforming), operating pressure, and inlet molar ratio at the feed 2,18–20,43 An additional operating condition has been varied for the blue hydrogen processes, that is, the percentage of CO 2 capture in the tail gas 8 …”

“…18 Depending on the process operating conditions, a substantial amount of CO is expected after the reforming stage, so the outlet from the reformer goes into a series of water gas shift reactors to increase the consumption of produced CO and maximize the H 2 production. 19 Two water gas shift reactors, high-temperature shift (HTS) and low-temperature shift (LTS), operating at different temperatures, have been considered. The catalytic reactions in the steam reforming process play a key role in the composition profiles and thus the efficiency of the process.…”

“…[11][12][13][14][15][16] However, it is important to realize that due to SMR's economic superiority over emerging hydrogen production methods, such as biological processes and renewable-powered electrolysis, and its significant role in meeting worldwide hydrogen demand, 17 a sudden shift from established SMR processes is not feasible. Accordingly, many efforts have been tested at the laboratory scale to improve further the steam reforming process, including catalysts preparation, 18 coupling SMR technology with membrane reactor to produce carbon monoxide (CO)free hydrogen, 19 using catalytic nonthermal plasma technology to develop a dielectric barrier discharge reactor, 20 implementing new catalysts in combination with a membrane reactor, 21 and process intensification through storage reactor. 22 These efforts are critical as they form the foundation for new advancements in SMR technology.…”

Barium Titanate as a Highly Stable Oxygen Permeable Membrane Reactor for Hydrogen Production from Thermal Water Splitting

“…Consequently, H 2 is obtained at the water side after steam condensation . Compared to traditional steam methane reforming (SMR), which is a mature technology to produce hydrogen, advanced water splitting using MIEC membranes can directly produce CO-free hydrogen . In addition, the use of such MIEC membranes makes it possible to combine water splitting with other important catalysis reactions (e.g., partial oxidation of hydrocarbon and oxidative dehydrogenation of alkanes) in a single step, , thus having the potential to reduce the hydrogen production cost.…”