Hydrogen Production by Sorption Enhanced Steam Reforming (SESR) of Biomass in a Fluidised-Bed Reactor Using Combined Multifunctional Particles

Abstract

The performance of combined CO2-sorbent/catalyst particles for sorption enhanced steam reforming (SESR), prepared via a simple mechanical mixing protocol, was studied using a spout-fluidised bed reactor capable of continuous solid fuel (biomass) feeding. The influence of particle size (300–500 and 710–1000 µm), CaO loading (60–100 wt %), Ni-loading (10–40 wt %) and presence of dicalcium silicate support (22.6 wt %) on SESR process performance were investigated. The combined particles were characterised by their density, porosity and CO2 carrying capacity with the analysis by thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH) and mercury intrusion porosimetry (MIP). All experiments were conducted with continuous oak biomass feeding at a rate of 0.9 g/min ± 10%, and the reactor was operated at 660 ± 5 °C, 1 atm and 20 ± 2 vol % steam which corresponds to a steam-to-carbon ratio of 1.2:1. Unsupported combined particles containing 21.0 wt % Ni and 79 wt % CaO were the best performing sorbent/catalyst particle screened in this study, when accounting for the cost of Ni and the improvement in H2 produced by high Ni content particles. SESR tests with these combined particles produced 61 mmol H2/gbiomass (122 g H2/kgbiomass) at a purity of 61 vol %. Significant coke formation within the feeding tube and on the surfaces of the particles was observed which was attributed to the low steam to carbon ratio utilised.

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

“…solar photovoltaics and wind energy [1]. Current global H2 production is around 75 Mt per annum, of which 76% is produced from natural gas (205 Gm 3 , or 6% of current global natural gas use) and 23% from coal (107 Mt, or 2% of global coal use), however, its production contributes about 830 Mt CO2 emissions to the atmosphere per year (2% of global annual emissions) [1]. With the rapid growth rate in H2 demand, CO2 emissions from hydrogen production are predicted to increase significantly, if it is supplied from natural gas or coal without carbon capture and storage (CCS) technologies.…”

“…One innovative option is sorption enhanced steam reforming (SE-SMR), which involves an in-situ CO2 capture process where the hydrocarbon fuel is reacted with steam in the presence of a CO2 sorbent and a reforming catalyst to generate decarbonised, high purity H2 [3]. The concept of SE-SMR is not new.…”

CO2 capture using solid sorbents: Fundamental aspects, mechanistic insights and recent advances

“…In response to this critique the authors performed thermogravimetric tests in pure CO2 and demonstrated a higher performance of the CaO modified by polymorphic spacers in this case as well [403]. Other studies contradict these results, showing CaO modified with Ca2SiO4 to still show the typical decay of unmodified CaO [402], [413], clearly highlighting the need for more analysis of these materials.…”

“…CH4 [671]- [674], biomass [413], glycerol [448], [675]- [678] or ethanol [679]- [682]), to capture CO2 at a high efficiency for a long time, and possibly to enable redox-reactions simultaneously for a better heat integration [683]- [686]. Combining these functionalities in a single particle (bi-functional or tri-functional catalyst-sorbent [687]) would maximize the heat integration of the different sub-reactions, but the design of such multifunctional materials is challenging so that typically separated particle systems (i.e.…”

H2 production from co-pyrolysis/gasification of waste plastics and biomass under novel catalyst Ni-CaO-C

“…Clough et al (2018) andBaidya and Cattolica (2015), Ni-CaO and Ni-CaO-Fe catalysts were used respectively. They performed regeneration by calcining the used catalysts under high temperature with air.…”