This study assessed, from the thermodynamic point of view, the feasibility of methane production using CO₂ present in raw biogas. The thermodynamic analysis of the Sabatier reaction was performed using the Aspen Plus software and considering in situ water removal to displace the reaction equilibrium. The temperature and pressure were varied between 200 – 450 °C and 1 – 30 atm respectively, the typical operation ranges of industrial catalysts. The CH₄/CO₂ molar ratio in the feed stream was also varied to evaluate the influence of biogas composition on methane yield and selectivity. Two types of multifunctional reactors could be considered depending on the value of the water removal fraction (R): a membrane reactor for 0 < R < 0.99 and a sorption-enhanced reactor for R ≥ 0.99. Their performance was compared to that obtained with a traditional reactor, i.e. without water removal (R = 0). Water removal increases the CH₄ yield but only up to an optimum R; above this value, coke formation is favoured. This optimum value depends on the temperature, pressure, CH₄/CO₂ ratio and was always below 0.99. The highest improvements on CH₄ yield were achieved for the lowest CH₄/CO₂ ratio considered. Water removal can be also particularly useful to minimize the production of CO_X allowing to comply with the biogas quality specifications for injection into the natural gas grid.

这项研究从热力学的角度评估了使用存在于原始沼气中的CO ₂进行甲烷生产的可行性。Sabatier反应的热力学分析是使用Aspen Plus软件进行的，并考虑了原位除水以取代反应平衡。温度和压力分别在200 – 450°C和1 – 30 atm之间变化，这是工业催化剂的典型操作范围。还改变进料流中的CH ₄ / CO ₂摩尔比以评估沼气组成对甲烷产率和选择性的影响。可以考虑两种类型的多功能反应器，具体取决于除水率（R）：0 <膜反应器 - [R  <0.99和用于吸附增强的反应器- [R  ≥0.99。将它们的性能与传统反应器（即不去除水（R  = 0））获得的性能进行了比较。除水可提高CH _4的收率，但仅可达到最佳R值。高于该值，则有利于结焦。该最佳值取决于温度，压力，CH ₄ / CO ₂比，并且始终低于0.99。对于所考虑的最低CH ₄ / CO ₂比，实现了CH ₄收率的最高改善。脱水也可能特别有用，可最大程度地减少CO的产生_X允许符合注入沼气池的沼气质量规格。