Carbon-negative syngas production: A comprehensive assessment of biomass pyrolysis coupling chemical looping reforming

This article introduces a pyrolysis chemical looping reforming (PCLR) process that produces carbon-negative syngas in autothermal operation. To enhance the system's carbon negativity, a process configuration with oxygen carrier two-stage regeneration is adopted, enabling internal CO2 utilization. The PCLR process is systematically evaluated and compared to chemical looping gasification and steam gasification processes in the process performance, energy efficiency, and environmental impact using a process model. Results reveal significant improvements over chemical looping gasification, including 69%, 45%, and 4% improvement in syngas yield, energy efficiency, and environmental benefit. Process analysis demonstrates that decoupling volatile reforming from pyrolysis and combustion enhances syngas quality, energy efficiency, and process flexibility. While the two-stage regeneration sacrifices syngas production, it contributes to a 4% increase in carbon negativity and a 15% reduction in carbon emissions. Thus, the PCLR process effectively overcomes the limitations of chemical looping gasification systems and exhibits excellent process intensification performance.