Infrared heating and synergistic effects during fast co-pyrolysis of corn stover and high alkali coal

Infrared heating method aids in the investigation of the primary volatiles-volatile interactions during co-pyrolysis by minimizing the secondary reactions. In this study, characteristics and synergistic effects during the rapid co-pyrolysis of high alkali coal (HAC) and corn stover (CS) using infrared heating were systematically investigated. The co-pyrolysis liquid yield initially increased and then decreased with increasing the pyrolysis temperature. The synergistic effects clearly promoted the tar yield and quality. The co-pyrolysis tar yields increased with rising temperature, from 23.29 wt% at 500 °C to 28.87 wt% at 700 °C, before decreasing to 23.57 wt% at 800 °C. At 700 °C, the largest deviation was 63%. Moreover, the co-pyrolysis interaction had a maximal negative deviation of − 35% for CO₂ mass at 700 °C, indicating that the co-pyrolysis of CS and HAC reduced carbon emissions. The tetracyclic and tricyclic aromatic hydrocarbons in PAHs were substantially reduced due to CS hydrogen radicals, and the quantities of the binary aromatic rings decreased by 50% with the increase in temperature. The presence of AAEMs in coal affected the bond breaking and reformation of molecular bonds within the tar components. Raman analysis and BET analyses suggested that AAEMs in HAC enhanced the reactivity of char. The interaction between the volatile of CS and HAC increased the amount of ammonia carbon and the number of active sites.