数值分析方法在一起高危工艺分析中的应用

以二级放热反应为研究对象,在反应体系温度、浓度均匀分布的假设基础上,根据反应速率方程和热平衡方程,建立高危工艺反应的温度和转化率随时间变化的数学模型。采用数值计算技术,以一阶差分代替微分,并结合工艺中的恒温过程、绝热过程和飞温过程,编写计算程序求得其转化率、温度在不同时间点的数值解,揭示爆炸事故的发展过程,定量分析操作参数的影响和转化率、温度随时间分布的规律。同时通过对绝热反应时间、冷凝器的冷却能力的分析,结合冷凝器的移热能力和反应放热对反应体系热积累的影响,讨论防止反应失控发生的可能性。最后探讨冷凝器热负荷余量、反应物投料浓度比等因素对控制反应失控的影响。

Application of Numerical Method in a High-risk Process Analysis

Based on the presumption of uniformed temperature and concentration distribution in the reactor space,a mathematical model for the change of reaction system temperature and conversion rate with time was established for a two-order exothermic reaction according to the kinetic equation and thermal balance equation.Through adopting numerical calculation technique and replacing first order differential with corresponding difference,the calculation programs were compiled under the condition of the isothermal step,adiabatic step,and run away step,and the numerical values of conversion rate and temperature at different time points were gained,which reveals the development process of explosion accidents.The influences of operating parameters,together with the distribution of conversion rate and temperature with time are quantitatively determined.By analyzing the adiabatic process duration and the cooling capacity of the heat exchanger,the occurring possibility of the run away reaction was discussed with consideration on the influence of the heat removing and heat releasing of heat exchanger on the accumulation of reaction system.At last,the influence of the design margin of the heat exchanger capacity and the concentration ratio of the reaction agents on the run away reaction was also discussed.