Abstract:

When the materials in the semi-batch tank reactor accumulate too much and the reaction exotherms too quickly, it is easy to cause the risk of thermal runaway and cause chemical safety accidents. A preferable feeding operation can avoid the risk of thermal runaway, shorten operation cycle, and improve production efficiency. In this work, a strategy for numerical optimization of the safe and efficient feeding operation is proposed, based on a mathematical model of semi-batch reactors and with hydrolysis of acetic anhydride as the model reaction. In this strategy, the range for safe feeding temperature is firstly determined under different feeding modes (e.g., one-stage, two-stage and three-stage), and then the specific feeding temperature corresponding to the shortest operating cycle is found within this temperature range. This feeding temperature is optimal. The results show that the range for safe feeding temperature and the optimal operating temperature for the three-stage feeding mode are 60.9% wider and 1.9 K lower than these of the one-stage feeding. The six-stage feeding mode can almost achieve the minimum operating cycle, and increasing the operating pressure can also shorten the operating cycle.

Key words: semi-batch reactor, thermal runaway, safety, numerical optimization, hydrolysis of acetic anhydride

摘要：

半间歇釜式反应器内物料积累过多且反应放热过快时，容易引发热失控风险，造成化工安全事故。设计较优的加料操作，既可以避免热失控风险，又可以缩短操作周期、提高生产效率。针对半间歇釜式反应器，以乙酸酐水解为模型反应，基于反应器数学模型，提出了一种安全高效加料操作的数值优化策略。在该策略中，首先确定不同加料方式（如一段、二段和三段加料）下的安全操作温度区间，然后在该温度区间内寻找最短操作周期对应的操作温度，该温度即为最佳的加料操作温度。优化结果表明三段加料的安全操作温度区间和最佳操作温度分别比一段加料宽60.9%和低1.9 K，六段加料已经基本可以实现操作周期最短，增加操作压力也有利于缩短操作周期。

关键词: 半间歇釜式反应器, 热失控, 安全, 数值优化, 乙酸酐水解