Complete Ca/Cu cycle for H2 production via CH4 sorption enhanced reforming in a Lab-Scale fixed bed reactor

Abstract

The three main reaction stages of a H 2 production process based on the combination of the CaO/CaCO 3 and Cu/CuO loops have been experimentally studied in a lab scale fixed bed reactor. The solid bed contained the three functional materials required to run the process, namely a commercial Ni-based catalyst, a CaO-Ca 12 Al 14 O 33 CO 2 sorbent and a CuO-Al 2 O 3 material in a proportion that resulted in a bed with 43.3 % wt. CuO, 25.6 % wt. CaO and 1.7 % wt. Ni. The system was able to convert 13.5 kg CH 4 h-1 kg Ni-1 , at 675 ºC producing a gas stream with a 93.5 % vol. H 2 at 10 bar. The Cu-based material presented high oxidation kinetics, being totally converted in a narrow reaction front with a highly diluted air stream at 10 bar. The Cu-based material presented also fast reduction kinetics and it was completely converted with a fuel gas with typical composition of a SMR stage at high temperature. A Cu/Ca molar ratio of 2 allowed for calcination efficiencies over 85 % molar basis at the CO and H 2 breakthrough , and 95 % of the CO 2 from CaCO 3 exited the reactor at CH 4 breakthrough. The experimental results have been validated with a pseudo homogeneous reactor model for the three reaction stages that *Manuscript Click here to view linked References

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

“…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.…”

Ca-Cu Chemical Looping Process for Hydrogen and/or Power Production

“…In this section, a revision on the recent developments of CaO and Cu-based materials suitable for this process is included. As for the catalyst, conventional Ni-based reforming catalysts have been typically proposed for this process [15,17], which have been successfully tested under suitable conditions for the Ca-Cu process [18,19]. It is important to assess the effect that the redox cycles have on catalyst activity and to determine the operational window in terms of CH 4 space velocity that a system sorbent/catalyst is able to convert.…”

“…Consecutive cycles of the three main reaction stages of the Ca-Cu looping process were made by Díez-Martín et al [19] in a lab-scale fixed-bed reactor (L = 0.2 m, I.D. = 18 mm) under relevant conditions of this process at a large scale.…”

Advanced Packed-Bed Ca-Cu Looping Process for the CO2 Capture From Steel Mill Off-Gases

“…In the Ca-Cu looping process, the exothermic reduction of CuO to Cu using a gaseous fuel (e.g., CH 4 , CO, or H 2 ) supplies the necessary heat to carry out simultaneously the calcination of the carbonated sorbent producing exclusively CO 2 and H 2 O without the presence of an ASU in the process (Fernández et al, 2012). A substantial progress has been made during the EU ASCENT project on dynamic reactor modeling (Martini et al, 2016(Martini et al, , 2017Fernández and Abanades, 2017a), development of Ca-Cu materials (Kazi et al, 2017), process integration (Riva et al, 2018;Martínez et al, 2019b), and experimental validation from small reactors to packed beds at TRL5 (Fernández and Abanades, 2017b;Grasa et al, 2017;Díez-Martín et al, 2018;Martínez et al, 2019a). Some recent works have proposed the use of the Ca-Cu based process to convert the BFG into valuable products, such H 2 /N 2 and pure CO 2 , using a combination of several interconnected fluidized beds operating in continuous mode (Fernández et al, 2017;Martínez et al, 2018).…”