Process simulations of blue hydrogen production by upgraded sorption enhanced steam methane reforming (SE-SMR) processes

Abstract

Clean and carbon-free hydrogen production is expected to play a vital role in future global energy transitions. In this work, six process arrangements for sorption enhanced steam methane reforming (SE-SMR) are proposed for blue H2 production: 1) SE-SMR with an air fired calciner, 2) SE-SMR with a Pressure Swing Adsorption (PSA) unit, 3) SE-SMR thermally coupled with Chemical-Looping Combustion (CLC), 4) SE-SMR+PSA+CLC, 5) SE-SMR+PSA with an oxy-fired calciner, 6) SE-SMR+PSA and indirect firing H2 combustion from the product stream recycle. The proposed process models with rigorous heat exchanger network design were simulated in Aspen Plus to understand the thermodynamic limitations in achieving the maximum CH4 conversion, H2 purity, CO2 capture efficiency, cold gas efficiency and net operating efficiency. A sensitivity study was also performed for changes in the reformer temperature, pressure, and steam to carbon (S/C) ratio to explore the optimal operating space for each case. The SE-SMR+PSA+H2 (Case 6) recycle process can achieve a maximum of 94.2% carbon capture with a trade-off in cold gas efficiency (51.3%), while a near 100% carbon capture with the maximum net efficiency of up to 76.3% is realisable by integrating CLC and PSA (Case 4) at 25 bar. Integration of oxy-fuel combustion lowered the net efficiency by 2.7% points due to the need for an air separation unit. In addition, the SE-SMR with the PSAOG process can be designed as a self-sustaining process without any additional fuel required to meet the process heat utility when the S/C ratio is ~3-3.5.

Techno-economic analysis of low-carbon hydrogen production by sorption enhanced steam methane reforming (SE-SMR) processes

“…In our previous work [18], we have investigated the thermodynamic performance and operating window of six upgraded SE-SMR processes for blue hydrogen production: 1) SE-SMR with an air fired calciner, 2) SE-SMR with a Pressure Swing Adsorption (PSA) unit, 3) SE-SMR thermally coupled with Chemical-Looping Combustion (CLC), 4) SE-SMR+PSA+CLC, 5) SE-SMR+PSA with an oxy-fired calciner, 6) SE-SMR+PSA with an indirect H2 -fired calciner. Only natural gas was used as a feedstock in the previous process simulations.…”

“…Compared to the current available SMR technologies with aqueous solutions of amines such as MEA, TEA and MDEA for decarbonised hydrogen production, the SE-SMR approach has the advantages of high yields of H2, high conversion of methane, low reforming temperature, without the requirement of multiple shift reactors and subsequent purification steps. Recently, extensive research has been carried out to develop highperformance CO2 sorbents for multiple SE-SMR/regeneration cycles [6][7][8][9][10][11][12], and to investigate the thermodynamic performance of different integrations of SE-SMR process for hydrogen production [13][14][15][16][17][18]. The main drawback of the SE-SMR technology is that to produce the calcination heat demand without emitting CO2 to the atmosphere requires energy-intensive processes like oxy-fuel combustion or the use of an indirectly heated calciner.…”

“…The results of thermodynamic analysis showed that the overall exergy efficiency of SE-SMR integrated with CLC increased by 14.39% points compared to SMR without CCS. Yan et al [18] evaluated the process performance of different SE-SMR configurations, which consisted of process integrations with PSA, CLC, oxy-fuel combustion or H2-fired calciner, and their results indicated that the upgraded SE-SMR processes could provide flexible options for low-carbon hydrogen production based on the costs and demand of CO2 reduction.…”

Hydrogen Technology, a Short Overview

“…Hydrogen can be produced through various processes [1], most of today's hydrogen production comes from fossil fuel processing, namely Coal Gasification, Methane Steam Reforming and Petroleum fraction partial Oxidation. Hydrogen produced by these processes is classified as 'Grey' [2] due to the gaseous pollutant emissions [4] although it is important to note that if Carbon Capture and Storage technology were to be implemented, then the produced Hydrogen would be classified as 'Blue' [3]. 'Green' Hydrogen [2] can only come through a process that, in all aspects, is zero-emission, the most well known system that can produce it is an R.E.S.…”

Analysis of the Heat Balance of a Metal Hydride Separator Used for the Separation of Hydrogen from Syngas

“…A method of hydrogen production that is more ecologically acceptable is the use of technologies that capture CO 2 during the production of hydrogen from fossil fuels and biomass. Such hydrogen is referred to as blue hydrogen, and according to multiple studies, it will play an important role in the industry decarbonisation [6,7]. This will enable the development and completion of a non-existing infrastructure for hydrogen management and will facilitate an increased demand for hydrogen on a global scale.…”