Rapid co-pyrolysis of rice straw and a bituminous coal in a high-frequency furnace and gasification of the residual char

Rapid pyrolysis of rice straw (RS) and Shenfu bituminous coal (SB) separately, and rapid co-pyrolysis of RS/SB blends (mass ratio 1:4, 1:4, and 4:1), were carried out in a high-frequency furnace which can ensure both high heating rate and satisfying contact of fuel particles. Synergies between RS and SB during rapid co-pyrolysis were investigated. Intrinsic and morphological structures of residual char from co-pyrolysis, and their effects on gasification characteristics were also studied. Synergies occurred during rapid co-pyrolysis of RS and SB (RS/SB = 1:4) resulting in decreasing char yields and increasing volatile yields. Synergies also happened during gasification of the char derived from co-pyrolysis of RS and SB with mass ratio of 1:4. The increased mass ratio of RS to SB did not only weaken synergies during co-pyrolysis, but significantly reduced the gasification rates of the co-pyrolysis char compared to the calculated values. Results can help to optimize co-conversion process of biomass/coal.

► Reactor can obtain high heating rates and good contact of particles in co-pyrolysis.
► Synergies during co-pyrolysis decrease char yields and increase volatile yields.
► The increasing rice straw/coal mass ratio weakens synergies during co-pyrolysis.
► Synergies on gasification of co-pyrolysis char vary with rice straw/coal mass ratio.