CO2-derived syngas production via pyrolysis of bamboo

Abstract

Meeting the growing demand for biofuels is constrained by the limited availability of biomass, of which only a fraction can be utilized without compromising food security or causing environmental harm. To address this challenge, bamboo, a fast-growing biomass, was employed as the feedstock for pyrolysis to produce gaseous biofuels. To impart a carbon-negative feature, carbon dioxide (CO2) was introduced as a co-reactant. CO2 participated in homogeneous reactions (HRs) with bamboo-derived volatiles, redistributing carbon from biocrude to syngas, particularly carbon monoxide (CO). The use of Co-or Ni-based catalysts further enhanced syngas production while simultaneously consuming CO2 by accelerating these CO2-driven reactions, with the Ni-based catalyst exhibiting superior performance in CO2. Syngas yield and CO2 consumption increased proportionally with CO2 loading. To improve syngas quality, an integrated thermochemical pathway was proposed, coupling CO2-mediated catalytic pyrolysis with the water gas shift (WGS) reaction to increase the H2/CO ratio via conversion of CO to H2. This approach demonstrated the potential for carbon negativity, with net negative CO2 emissions achievable. The estimated revenue from H2 production and the economic benefit of CO2 mitigation were valued at 141.4 billion USD, representing a 7-fold increase compared with the conventional pyrolysis process. These results highlight CO2-mediated catalytic pyrolysis of bamboo as a promising strategy for carbon-negative syngas production.