Effects of feedstock on co-pyrolysis of biomass and coal in a free-fall reactor

The effects of feedstock on the co-pyrolysis of biomass and coal were investigated in a free-fall reactor from 500°C to 700°C with a biomass blending ratio of 0 to 100%. The selected coal samples were Dayan brown coal (DY) and Tiefa bituminous coal (TF), and the biomass samples were agricultural residues legume straw (LS) and woody residues pine sawdust (SD). The results indicate that synergy can occur even in a short-gas-residence time during the co-pyrolysis of biomass and coal in a free-fall reactor. The product yields and the CO2 reactivity of char from the co-pyrolysis are greatly influenced by the type of feedstock. The synergy in the presence of LS with high holocellulose and ash content is more significant than that in the presence of SD. The liquid yield of high-rank TF coal co-pyrolysis is higher than that of low-rank DY coal. The char reactivity can be improved by the co-pyrolysis at specific conditions. The co-pyrolysis in the presence of DY can improve the reactivity of the char produced.