Flexible strategies for carbon-negative syngas and biochar poly-generation via a novel chemical looping approach

Abstract

This work proposed a pyrolysis chemical looping reforming-two stage regeneration (PCLR-TR) process with carbon-negative syngas and biochar poly-generation，aimed at overcoming challenges in chemical looping gasification. The process effectively separates pyrolysis and reforming, circumventing slow solid–solid reactions and enabling the flexible adjustment of the H₂/CO ratio. The two-stage regeneration ensures improved synchronization of reaction rates across different reactors. The results indicate that manipulation of process parameters allows for flexible adjustment of the H₂/CO ratio in syngas (ranging from 1.02 to 3.83). The introduction of CO₂ feed in the first stage regeneration reactor reduces the oxygen carrier exothermic intensity in the second stage regeneration reactor by 58%. Optimization results suggest that the generated syngas is compatible with diverse downstream applications, exhibiting a maximum CO₂ negative emission of 1.85 kg/kg syngas. The PCLR-TR system offers a versatile and environmentally friendly solution for the energy and chemical industries.