A Dual-Benefit Flash Pyrolysis for Valorizing Carbonaceous Wastes into High-Calorific Syngas (94.7 vol% Combustibles) and Battery Anodes

Abstract

Traditional low-temperature slow pyrolysis (LTSP) is inefficient, constrained by low temperatures (300-1000°C) and prolonged durations, leading to poor kinetics and high energy demand. This work demonstrates an innovative in-situ Joule heating technology to achieve ultra-high temperature flash pyrolysis (UHTFP) at over 3000°C in approximately one second. This method ensures complete pyrolysis, resulting in enhanced product purity, efficiency, and yield compared to LTSP. The versatility of UHTFP is highlighted by its exceptional product selectivity: pyrolysis of anthracite yields a hydrogen-rich gas (up to 83.7% H₂), while bituminous coal is efficiently converted into a premium, high-calorific syngas, with combustible monomers (H₂, CO, CH₄) constituting an impressive 94.7% of the product gas. Molecular dynamics simulations show that, the ultra-high temperature system in a non-equilibrium state can generate numerous free radicals, causing the carbon atoms condensed into flash graphene, and the heteroatoms fragmentated into small gas molecules. Moreover, the obtained flash graphene can be used as the negative electrode of lithium-ion batteries, exhibiting a specific capacity of 326.83mAh/g. The UHTFP technology is versatile and scalable, capable of swiftly processing materials like coal, biomass, and waste plastics, offering significant economic and environmental advantages for chemical and energy production.