The synthesis of vinyl acetate (VAc) from ethylene is a strongly exothermic reaction that might easily cause catalyst deactivation and reduce selectivity of VAc. Research at the bed scale helps to improve the conversion of C 2 H 4 and the selectivity of VAc. In this study, the discrete element method (DEM) was used to construct a fixed-bed structure model via simulating the filling process of catalyst particles in the reactor. The inlet section of a reaction tube was studied, and its length was 10 cm. The temperature distribution, and the effects of particles size, inlet velocity, inlet temperature and the feed ratio of C 2 H 4 to O 2 on the reaction process were studied. Simulated results show that the bed temperature gradually increased from the wall to the center, and the temperature gradient gradually decreased along the radial direction. The maximum temperature was 438.68 K and the temperature difference from the inlet temperature was 5.54 K. Comparing the composite particle packed bed with the single particle size packed bed, the composite packed bed has higher vinyl acetate selectivity. Increasing inlet velocity from 1.5 m/s to 3.5 m/s, the selectivity of vinyl acetate increased from 91.71% to 92.60%. Adding an inert gas to the feed gas can increase the oxygen concentration and reduce the explosion interval of QH4, the conversion of C 2 H 4 and the selectivity of vinyl acetate increased.

中文翻译：

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固定床反应器中乙烯气相合成醋酸乙烯酯的粒子分辨 CFD 模拟

由乙烯合成乙酸乙烯酯 (VAc) 是一个强烈的放热反应，很容易导致催化剂失活并降低 VAc 的选择性。床规模的研究有助于提高 C 2 H 4 的转化率和 VAc 的选择性。在本研究中，通过模拟反应器中催化剂颗粒的填充过程，采用离散元法（DEM）构建固定床结构模型。研究了反应管的入口部分，其长度为10cm。研究了温度分布以及粒径、入口速度、入口温度和C 2 H 4 与O 2 的进料比对反应过程的影响。模拟结果表明，床层温度从壁向中心逐渐升高，温度梯度沿径向逐渐减小。最高温度为438.68 K，与入口温度的温差为5.54 K。复合颗粒填充床与单一粒径填充床相比，复合填充床具有更高的醋酸乙烯选择性。将入口速度从 1.5 m/s 提高到 3.5 m/s，醋酸乙烯酯的选择性从 91.71% 提高到 92.60%。在原料气中加入惰性气体可以提高氧气浓度，缩短QH4的爆炸间隔，提高C 2 H 4 的转化率和醋酸乙烯的选择性。5 m/s，醋酸乙烯的选择性从91.71%提高到92.60%。在原料气中加入惰性气体可以提高氧气浓度，缩短QH4的爆炸间隔，提高C 2 H 4 的转化率和醋酸乙烯的选择性。5 m/s，醋酸乙烯的选择性从91.71%提高到92.60%。在原料气中加入惰性气体可以提高氧气浓度，缩短QH4的爆炸间隔，提高C 2 H 4 的转化率和醋酸乙烯的选择性。