Development of Suitable CuO-Based Materials Supported on Al₂O₃, MgAl₂O₄, and ZrO₂ for Ca/Cu H₂ Production Process

Abstract

Functional materials for the sorption enhanced reforming process for H 2 production coupled to a Cu/CuO chemical loop have been synthesized. The performance of CuObased materials supported on Al 2 O 3 , MgAl 2 O 4 and ZrO 2 and synthesized by different routes has been analyzed. Highly stable materials supported on Al 2 O 3 or MgAl 2 O 4 synthesized by co-precipitation and mechanical mixing with sufficient Cu loads (around 65 %wt.) have been successfully developed. However, it has been found that coprecipitation under these conditions is not a suitable route for ZrO 2. Spray-drying and deposition precipitation did not provide the best chemical features to the materials. As the Ca/Cu process is operated in fixed bed reactors, the best candidates were pelletized and their stability was again assessed. Pellets with high chemical and mechanical stability, high oxygen transport capacity and good mechanical properties have been finally obtained by co-precipitation. The good homogeneity that provides this route would allow an easy scaling up.

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

“…The material has been prepared by co-precipitation and it presents an stable oxygen transport capacity (OTC) of 0.149 mg. O/mg. oxidized material, as determined through more than 100 oxidation/reduction cycles in a TGA apparatus [30]. The material was pelletized and the final particle size was in a range 0.6-2 mm to form a homogeneous bed with the sorbent and catalyst.…”

“…[53]. For the kinetics of the Cu oxidation and CuO reduction, an SCM with cylindrical geometry recently published for the material involved in this work has been considered (See Table 1, [30,42]). The amount of Ni present in bed is low (less than 2 % wt.…”

“…Cu-based oxygen carriers with sufficient active content (Cu loads over 60 % wt.) have been also synthesized [29,30], which have demonstrated to be resistant to agglomeration and deactivation in the long term. Some recent works are oriented to the development of composite materials containing CaO and CuO [31][32][33][34][35] and/or CaO and Ni acting as reforming catalyst [36,37] that have been tested in TGA and fixed bed reactors.…”

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

“…However, despite some works reporting stable OTC along a reduced number of cycles [34], there are not many works published so far about highly loaded Cu materials specifically prepared for operation in fixed-bed reactors in pellet or large-particle form. A recent paper from Díez-Martín et al [35] evaluated the maximum CuO load onto different inert supports (Al 2 O 3 , MgAl 2 O 4 , ZrO 2 ) that allowed chemically and mechanically stable materials along representative conditions for the Ca-Cu process. According to the results from this work, it was possible to produce chemically and mechanically stable pellet materials with Cu contents up to 65% wt.…”

A calcium zirconate based combined material for calcium-copper chemical looping technology

“…freeze granulation and sol-gel combustion are hurdles that must be overcome for large scale deployment. In the case of reported co-precipitation methods, Cu/Al2O3 systems seem favourable relative to Cu/Zr due to formation of monoclinic ZrO2 that causes a poorer dispersion of Cu and Zr in the material (Laura Díez-Martín et al, 2018). A drawback of Cu/Al systems can on the other hand be strong Cu-support interactions that can result in reduced carrying capacities (i.e.…”