Effect of temperature oscillation on torrefaction and pyrolysis of elm branches

The temperature would oscillate when the industrial flue gas was used as the heat source for biomass torre-faction. In order to explore the influence of temperature oscillation on torrefied products and subsequent py-rolysis, the torrefaction experiments of elm branches at different temperatures (220, 250, 280 degrees C) and different oscillation conditions (no oscillate as T0, weak oscillate as T0.5, strong oscillate as T1) were carried out on a vertical furnace, and then torrefied samples were pyrolyzed on a thermal synthesis analyzer (TG-DSC). The re-sults showed that the O/C and H/C of T1280 samples were decreased by 48% and 27% respectively compared with the raw sample, and the calorific value of T0.5280 sample was increased by 50.3%. The maximum weight loss rates of elm branches during subsequent pyrolysis were increased by the weak oscillation after torrefaction temperature of 220 and 250 degrees C. Temperature oscillation increased the pyrolysis activation energy of elm branches, and with the increase of torrefaction temperature, the value showed an increasing trend, and T1280 sample had the highest value about 87.53 kJ/mol. The differential scanning calorimetry (DSC) curve showed that the temperature oscillation of torrefaction inhibited the intensity of the subsequent pyrolysis reaction.

Automated summary

This study investigated the influence of temperature oscillation on torrefied products and subsequent pyrolysis by conducting torrefaction experiments on elm branches at different temperatures and oscillation conditions. The results showed that temperature oscillation reduced the O/C and H/C ratios of the torrefied samples and increased their calorific value. It also increased the pyrolysis activation energy of the elm branches, with a higher value at higher torrefaction temperatures.