Influence of Brown’s Gas on Cracking Behavior of Gas-Phase Tar during Pine Wood Pyrolysis

Abstract

The effect of Brown’s gas on the gas-phase tar cracking behavior, carbonic oxide (CO) production rate, and gaseous product temperature during the pine wood pyrolysis was preliminarily explored. By the application of cold trapping and gravimetric methods, it was found that Brown’s gas reduces the energy barrier of thermochemical conversion for gas-phase tar, widens the temperature range of gas-phase tar accelerated cracking, and increases the cracking rate. When the pyrolysis temperature increases by 1 °C, the average cracking rate of gas-phase tar increases from C = 4.58 g⋅Nm−3 (flow volume ratio of Brown’s gas to nitrogen, X(Brown’s gas):N2 = 0%) to C = 4.8 g⋅Nm−3 (X:N2 = 1%) and C = 5.02 g⋅Nm−3 (X:N2 = 5%). While participating in the deep cracking of gas-phase tar, Brown’s gas reduces the conversion energy barrier of the gas-phase tar to CO. The CO production rate rises from the initial 1.87% (X:N2 = 0%) to 4.22% (X:N2 = 1%) and 5.52% (X:N2 = 5%) per 1 °C of increased pyrolysis temperature. The consumption of Brown’s gas is 0.32 m3 per 1 g⋅Nm−3 of gas-phase tar cracking within the pyrolysis residence time of 30 min.