Abstract In pharmaceutical and fine chemical industries, fast and strongly exothermic reactions are often carried out in semibatch reactors (SBRs) to better control the heat evolution by the feeding rate. In fact, for such processes, a thermal runaway event may be triggered whenever the rate of heat removal becomes lower than the rate of heat production. Such a dangerous phenomenon consists in an uncontrolled reactor temperature increase that, occurring in practically adiabatic conditions, can trigger secondary undesired exothermic reactions or, worse, decompositions of the whole reacting mixture with consequent reactor pressurization due to uncontrollable gases formation. In this work, dedicated software has been developed and used to simulate a cooling system breakdown in an industrial SBR where the nitration of 4-Chlorobenzotrifluoride is carried out. The mathematical model is able to simulate both reactor temperature and pressure vs. time profiles thanks to a complete description of both the desired reaction and the unwanted reacting mixture decomposition kinetics. Different accidental scenarios have been simulated, showing both the wide different consequences that can arise from the same initiating event and, therefore, the usefulness of a complete simulation of the hypothesized accidental scenario in the frame of a Quantitative Risk Analysis.

中文翻译：

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4-Chloro-3-nitrobenzotrifluoride 的合成：由于冷却系统故障引起的工业热失控模拟

摘要 在制药和精细化工行业，为了通过进料速度更好地控制放热，通常在半间歇式反应器（SBR）中进行快速强放热反应。事实上，对于这样的过程，只要热量去除率变得低于热量产生率，就可能触发热失控事件。这种危险的现象在于反应器温度不受控制地升高，这种升高发生在实际上绝热条件下，会引发二次不希望的放热反应，或者更糟的是，整个反应混合物分解，随后由于无法控制的气体形成而导致反应器加压。在这项工作中，已开发出专用软件并用于模拟工业 SBR 中的冷却系统故障，其中进行 4-氯代三氟化物的硝化。由于对所需反应和不需要的反应混合物分解动力学的完整描述，数学模型能够模拟反应器温度和压力随时间变化的曲线。模拟了不同的意外情况，显示了同一起始事件可能产生的广泛不同的后果，因此，在定量风险分析的框架内对假设的意外情况进行完整模拟的有用性。由于对所需反应和不需要的反应混合物分解动力学的完整描述，时间曲线。模拟了不同的意外情况，显示了同一起始事件可能产生的广泛不同的后果，因此，在定量风险分析的框架内对假设的意外情况进行完整模拟的有用性。由于对所需反应和不需要的反应混合物分解动力学的完整描述，时间曲线。模拟了不同的意外情况，显示了同一起始事件可能产生的广泛不同的后果，因此，在定量风险分析的框架内对假设的意外情况进行完整模拟的有用性。