This paper encompasses the development of energy balance models to determine temperature dynamic behavior in single- and two-stage anaerobic digestion systems. Modeling assumptions were made according to the reactor type, its operation, energy exchanges, thermodynamics, and kinetics, as well as involved processes, substances, and phases. Stirring, heating, stream enthalpies, and reaction energies from biochemical processes were taken as the main external inputs. The temperature effect on specific growth constants was determined with a cardinal model. A general energy balance was obtained for a non-adiabatic, non-isothermic, triphasic single stage continuous stirred tank reactor digester, and then it was adapted to the case of a two-stage biohydrogen and biomethane mass balance model to obtain a multi-stage energy balance. The model was implemented and simulated in Modelica, then compared with data from a real-life experiment consisting of the digestion of a 1% glucose solution. Concentration and temperature evolution in both stages were analyzed. Temperature changes due to reaction enthalpies were observed mainly in the first stage, hydrolysis being the predominant process at the startup, followed by sugar acidogenesis. The main mechanics of the proposed model were demonstrated, and a reasonable approximation of the expected results was obtained.

中文翻译：

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为多级 CSTR 厌氧消化系统建模以反应器为中心的能量平衡

本文包括能量平衡模型的开发，以确定单级和两级厌氧消化系统中的温度动态行为。根据反应器类型、其操作、能量交换、热力学和动力学以及涉及的过程、物质和相进行建模假设。来自生化过程的搅拌、加热、流焓和反应能量被作为主要的外部输入。温度对特定生长常数的影响用基数模型确定。获得了非绝热、非等温、三相单级连续搅拌釜式反应器消化器的一般能量平衡，然后将其适应于两级生物氢和生物甲烷质量平衡模型的情况，得到多级能量平衡。该模型在 Modelica 中实现和模拟，然后与来自真实实验的数据进行比较，该实验包括消化 1% 葡萄糖溶液。分析了两个阶段的浓度和温度变化。由于反应焓引起的温度变化主要在第一阶段观察到，水解是启动时的主要过程，其次是糖酸化。证明了所提出模型的主要机制，并获得了对预期结果的合理近似。水解是启动时的主要过程，其次是糖酸化。证明了所提出模型的主要机制，并获得了对预期结果的合理近似。水解是启动时的主要过程，其次是糖酸化。证明了所提出模型的主要机制，并获得了对预期结果的合理近似。