Abstract In the present study, the effects of the absolute pressure (0.1 or 0.5 MPa) and the reactor atmosphere (pure N2 or a mixture of CO2/N2) on the pyrolysis behavior of wheat straw pellets (at 500 °C) were investigated. The most interesting aspect of this work was the use of a weighing platform (with a maximum capacity of 100 kg and a resolution of 0.5 g) to monitor the real-time mass-loss data for the biomass sample (with an initial mass of 400 g). It was observed that an increased pressure considerably affects the mass-loss profiles during the pyrolysis process, leading to higher devolatilization rates in a shorter period of time. Regardless of the pyrolysis atmosphere, an increase in the absolute pressure led to higher yields of gas at the expense of produced water and condensable organic compounds. This finding could be due to the fact that an increased pressure favors the exothermic secondary reactions of the intermediate volatile organic compounds in both liquid and vapor phases. The switch from pure N2 to a mixture of CO2 and N2 at 0.1 MPa also led to a remarkable increase in the yield of produced gas at the expense of the total liquid. This could be mainly due to the promotion of the thermal cracking of the volatile organic compounds at a high partial pressure of CO2, which is also consistent with the measured higher yields of CH4 and CO. The increased yield of CO can also be seen as a direct result of the enhanced reverse Boudouard reaction, which can also explain the much higher specific surface area (and ultra-micropore volume) measured for the biochar produced under the same operating conditions (0.1 MPa and a mixture CO2/N2 as pyrolysis medium).

中文翻译：

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小麦秸秆在实验室规模反应器中常压和加压缓慢热解过程中质量损失率的演变

摘要 在本研究中，研究了绝对压力（0.1 或 0.5 MPa）和反应器气氛（纯 N2 或 CO2/N2 的混合物）对小麦秸秆颗粒热解行为（500 °C）的影响。这项工作最有趣的方面是使用称重平台（最大容量为 100 kg，分辨率为 0.5 g）来监测生物质样品（初始质量为 400 G）。据观察，增加的压力显着影响热解过程中的质量损失曲线，导致在更短的时间内更高的脱挥发分率。无论热解气氛如何，绝对压力的增加都会导致更高的气体产率，但会损失采出水和可冷凝的有机化合物。这一发现可能是由于压力增加有利于中间挥发性有机化合物在液相和气相中的放热二次反应。从纯 N2 转换为 0.1 MPa 的 CO2 和 N2 混合物也导致了以总液体为代价的产气产量的显着增加。这可能主要是由于在高 CO2 分压下促进了挥发性有机化合物的热裂解，这也与测得的 CH4 和 CO 产率较高是一致的。CO 产率的增加也可以看作是增强的反向 Boudouard 反应的直接结果，这也可以解释在相同操作条件下（0.