Chemical looping co-gasification of rice straw and waste agricultural plastics with composite oxygen carriers of CaO/ Fe2O3 for syngas production: Product yields and gasification performances analysis

The chemical looping co-gasification (CLCG) characteristics of rice straw (RS) and waste agricultural plastics (WAP) were investigated using composite oxygen carriers (OCs) of CaO/Fe2O3 in a horizontal tubular furnace. The influences of OCs-to-feedstock ratio (OCs/F), WAP-to-RS ratio, reaction temperature, oxygen carrier components, and cyclic tests were investigated. The results indicated that gas yields first increased with the OCs/F increasing, but then decreased as the OCs/F exceeded 1:1. The maximum gasification efficiency (GE), carbon conversion rate (ηC), syngas content (S), and total syngas yield (Gv) were obtained at an OCs/F of 1:1, with values of 48.61%, 58.94%, 38.41%, and 0.57 Nm3/kg, respectively. When the WAP ratio in the feedstock was 0.25, the GE and ηC reached their peak values of 46.86% and 59.09%, respectively. With the temperature increasing, both GE and ηC showed an initial rise followed by a decline, reaching peak values of 58.9% and 48.6% at 800 °C, respectively. Regarding the effects of OCs components, the maximum GE and ηC were separately 63.66% and 51.00% at the Fe2O3-to-CaO ratio of 1:2. The cyclic tests revealed that the OCs would exhibit certain signs of sintering and deposition after multiple cycles, leading to reduced reactivity, diminished syngas output, and impaired gasification performance.