Abstract:

The process of methyl nitrite (MN) regeneration is a key step in scale-up of synthesis of alkyl esters. To maximize the real atom economy of the process, CO coupling reaction and MN regeneration need to be optimized and proceed at the same reaction rate. Studies on the process and kinetics of MN regeneration are reported. But few mathematical models for MN regeneration in a packed column are available. By analyzing the important reactions of MN regeneration, a mathematic model of MN regeneration in a packed column was developed with the reported kinetic parameters. The effect of main reaction parameters on MN yield was studied. The simulation results showed that MN yield increased with increasing liquid velocity and NO/O₂ mole ratio but decreased with increasing temperature, gas velocity and N₂ volume fraction. The simulation results were verified by experiments under different conditions, which proved that this model could be used for the design and operation of MN regeneration. Furthermore, the simulation results at two different mixing modes of NO and O₂ were presented.

Key words: methyl nitrite, packed column, mathematical modeling, regeneration, absorption

摘要：

在气相偶联合成草酸酯工艺过程中,亚硝酸甲酯(MN)再生过程与偶联反应有效匹配是实现整个系统绿色无污染的关键,也是影响草酸酯合成工业放大过程的关键一步。对于MN再生过程的工艺优化和宏观动力学方面进行了较多研究和报道,而对MN再生过程的数学模拟研究较少。通对MN再生过程中发生的主要化学反应进行分析简化,并结合MN再生反应动力学参数,在填料塔中建立了MN再生反应数学模型,并计算了主要工艺参数对MN收率的影响。模拟结果表明,随温度升高、气体流速增大、N₂体积分数增大,MN的收率减小,液体流速增大和NO/O₂摩尔比增大,MN收率增大。通过实验验证了该模型的准确性,MN收率的模拟结果与实验数据的最大相对偏差为-4.39%,为MN再生反应过程的设计和操作提供了理论依据;最后,对于两种不同的NO和O₂混合方式进行了比较,通过模拟计算比较了这两种不同操作方式对MN收率的影响。

关键词: 亚硝酸甲酯, 填料塔, 数学模拟, 再生, 吸收