Abstract Dynamic pyrolysis tests of coffee grounds residues (CGR) at heating rates in the range from 5 to 100 °C/min and at maximum temperature of 500 °C were carried out using a thermogravimetric analyser coupled to a mass spectrometer (TG-MS), for online evolved gas analysis, to determine kinetic parameters of thermochemical decomposition of CGR and its biopolymer constituents. During the pyrolysis, the maximum decomposition rate of each biomass component increased linearly with the heating rate. The slope increased with the biopolymer reactivity in the following sequence: hemicellulose > celluose > lignin. Main gases produced during the pyrolysis of CGR were oxygen containing species derived from parent biopolymers and primary and secondary vapours (250–425 °C), primarily H 2 O, followed by CO and CO 2 . The use of the Beta zeolite had only negligible effect on deoxygenation reactions, however it significantly promoted cracking reactions of pyrolysis vapours increasing the light hydrocarbons (C 1 –C 2 ) formation with the subsequent improvement in the heating value of the pyrolysis gas. Kinetic parameters for any of the individual biopolymers in CGR were estimated using the model-free isoconversional dynamic methods Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) models. The average value for the apparent activation energy of the individual biopolymers (hemicellulose, cellulose and lignin) in CGR calculated by KAS and FWO methods were estimated as 214, 241 and 266 kJ/mol, respectively; whilst for the CGR as a whole it was 242 kJ/mol. The two model-free isoconversional dynamic methods have been shown to be useful tools for assessment of biomass pyrolysis kinetic parameters, as they can provide E a values for use in reactor design models.

中文翻译：

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咖啡渣的热化学分解：动力学研究

摘要 使用与质谱仪 (TG-MS) 联用的热重分析仪在 5 至 100 °C/min 的加热速率和 500 °C 的最高温度下对咖啡渣残渣 (CGR) 进行动态热解测试。 ，用于在线逸出气体分析，以确定 CGR 及其生物聚合物成分的热化学分解动力学参数。在热解过程中，每种生物质组分的最大分解速率随加热速率线性增加。斜率随着生物聚合物反应性按以下顺序增加：半纤维素 > 纤维素 > 木质素。CGR 热解过程中产生的主要气体是来自母体生物聚合物和初级和次级蒸汽 (250–425 °C) 的含氧物质，主要是 H 2 O，其次是 CO 和 CO 2。Beta 沸石的使用对脱氧反应的影响可以忽略不计，但它显着促进了热解蒸汽的裂化反应，增加了轻烃 (C 1 -C 2 ) 的形成，随后热解气的热值得到了提高。使用无模型等转化动力学方法 Kissinger-Akahira-Sunose (KAS) 和 Flynn-Wall-Ozawa (FWO) 模型估计 CGR 中任何单个生物聚合物的动力学参数。通过 KAS 和 FWO 方法计算的 CGR 中单个生物聚合物（半纤维素、纤维素和木质素）的表观活化能的平均值分别估计为 214、241 和 266 kJ/mol；而对于整个 CGR 来说，它是 242 kJ/mol。