The effect of Copper(II) oxide loading and precursor on the cyclic stability of combined mayenite based materials for calcium copper looping technology

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

“…In general, and as mentioned in the introduction, it is not straight forward to directly compare the presented combined material and other combined materials due to the varying testing conditions employed. However, it is interesting to note that the described behaviour of the CaO/CuO/CaZrO3 40 and 50 wt% CuO loaded materials CuO40_R2 and CuO50_R2 are similar to those obtained for mayenite based materials (CaO/CuO/Ca12Al14O33) at a CuO/CaO = 2.0 [wt/wt] observed in our previous work (Westbye et al, 2018), where 50 wt% CuO loaded materials deactivated regardless of CuO precursor (CuO powder, Cu(OH)2 and Cu(NO3)2) while 40 wt% loaded materials remained stable throughout cycling.…”

“…Powder X-ray Diffraction Data (PXRD) All Bragg peaks have been accounted for and identified as CaO, CuO, CaZrO3, CaCu2O3 and Ca2CuO3 in the X-ray diffraction data collected for CuO40_R2 and CuO50_R2 (Figure 1). Mixed calcium-copper phases were expected as they have been observed in combined materials based on mayenite (CaO/CuO/Ca12Al14O33) (Westbye et al, 2018). For mayenite materials, these mixed phases segregated into separate CaO and CuO phases during cyclic TGA testing.…”

“…The cyclic TGA testing and the TGA equipment have been reported in detail by our research group in a previous article (Westbye et al, 2018). The implemented testing regime (Table 1) simulates representative Ca-Cu Looping conditions.…”

“…It was found that high calcination temperature and steam seamed to improve sorbent function. Our group have recently reported a mayenite based CaO/CuO/Ca12Al14O33 material (CuO/CaO = 2.0 [wt/wt]) prepared using a hydrothermal synthesis route (Westbye et al, 2018). It was found that 50 wt% CuO loaded materials lost oxygen carrying capacity regardless of CuO precursors while 40 wt% materials all showed stable cyclic TGA behaviour across 40 cycles for both CaO and Cu phases (steam used during TGA testing, 650 -870°C TGA temperatures).…”

Bauxite waste with low Fe 2 O 3 and high Na concentration as a promising oxygen carrier in chemical looping combustion

“…Hence, commercial applications of CLC is heavily dependent on the availability of high‐performance and cost‐effective OCs. Properties necessary for an effective OC include the following: high oxygen transport capacity, which reduces the demand of bed materials circulating in the CLC unit and, as a result, lowers the unit size and running cost; high redox reactivity, as the OC is supposed to convert fuel and then be re‐oxidized by air alternatively in a short time; durable cyclic stability, as the OC is supposed to be agglomeration resistance and maintain its performance during the circulation as long as possible; high mechanical strength, which is helpful to mitigate the adverse effects of attrition and crushing of the OC particles during the operation; low cost, since the possible commercial applications of CLC have been taken seriously the primary concern is to develop cost‐effective OCs; and environment‐friendly, the OC must be non‐toxic to eliminate the potential hazards for ecological environment as much as possible. Iron‐based OCs have distinguished themselves from the other candidates (eg, Ni, Mn, Cu, and Co based OCs) and been considered as the most competitive OCs as they best meet the above evaluation criteria .…”