In-depth exploration of mechanism and energy balance characteristics of an advanced continuous microwave pyrolysis coupled with carbon dioxide reforming technology to generate high-quality syngas

[Display omitted] •Continuous microwave pyrolysis coupled with CO2 reforming technology was studied.•Syngas yield after CO2 reformation was 85.70 vol% higher than that reported recently.•The introduction of CO2 helped to decrease H2S content from 0.43 vol% to 0.14 vol%.•CO2 intensified pyrolysis and reacted with products to improve syngas yield.•The mechanism and energy balance of this advanced technology were explored. This study firstly coupled advanced continuous microwave pyrolysis with CO2 reforming technology to recover syngas from cow manure and CO2. The contribution of CO2 to syngas, pyrolysis mechanism, and energy balance characteristics were analyzed thoroughly. The results showed that continuous microwave pyrolysis coupled with CO2 reforming technology has superiorities over other pyrolysis methods in bio-gas generation. The bio-gas yield, syngas content, and heating value of syngas reached the maximum value of 71.02 wt%, 85.70 vol%, and 10.87 MJ/Nm3, respectively. CO2 strengthened pyrolysis and reacted with pyrolysis products to produce high-quality syngas and reduce H2S. Due to the limited substances that can react with CO2 and excessive energy consumption with increasing CO2 concentration, the utilization efficiencies of CO2 and energy decreased from 36.31% and 27.27% to 31.16% and 24.24%, respectively. This work provides basic theory and technical support for advanced technology to recover high-quality syngas from biomass with low energy consumption.