Sorption-enhanced chemical looping steam reforming coupled with water splitting for syngas and H 2 coproduction using waste plastic as fuel

Chemical looping is a promising technology for hydrogen production. Achieving both high purity and yield is an ongoing challenge, due to low fuel conversion and carbon deposition. In this study, a sorption-enhanced chemical looping reforming coupled with water splitting (SE-CLSR-WS) process was proposed to co-produce syngas and H 2 by using waste plastic as the fuel. The Ni-doped Ca 2 Fe 2 O 5 brownmillerites were designed and employed as oxygen carriers (OCs) and CO 2 sorbent. The introduction of Ni leaded to lattice distortion of brownmillerite, thereby enhancing the redox activity of lattice oxygen. In fuel reactor (FR), CaO in-situ captured CO 2 and shifted reaction equilibrium towards PET pyrolysis gas reforming, enhancing both syngas yield and PET conversion rates. Adhere to the surface of OCs, CaO improved cyclic performance by inhibiting agglomeration of active metals. Calcination reactor (CR) was set between FR and steam rector (SR) to in-situ desorb CO 2 and remove carbon deposition, enhancing hydrogen purity in SR. When Ca 2 Ni 0.75 Fe 1.25 O 5 -0.25CaO was applied to SE-CLSR-WS process, it exhibited synergistically strengthened performance in reaction activity, sorption capacity and cyclic stability, with a syngas purity of 82.71 % and H 2 yield of 8.01 mmol/g OC with 93.26 % purity.