硝基苯精馏再沸器安全分析与评估

为了明确硝基苯精馏再沸器装置爆炸事故发生的原因,有针对性的采取预防措施,综合运用英国帝国化学工业公司的IC I蒙德评价法和事故树分析（FTA）法对精馏再沸器进行安全分析研究,确定了该装置生产过程中的物料物质系数,计算相关的物质危险性、工艺危险性和毒性指数,经过安全措施补偿系数修正后,得出了硝基苯精馏再沸器总危险性系数和危险等级;定性地分析了各危险因素的大小;定量地得出装置的危险程度,并提出了安全措施。结果表明,该装置的危险等级属中等,高温下漏入空气、阀门失效和法兰密封不严是导致该事故的3个最主要的原因,因此,应从以上几方面采取措施,加强安全生产管理。控制精馏再沸器的加热温度,防止局部积累热量,从而降低危险等级,确保安全生产。

Safety analysis and evaluation of reboiler in nitrobenzene rectification unit

The explosions of the reboiler in the rectifying unit of nitrobenzene processes occurred frequently.For figuring out the general causes and taking effective countermeasures for prevent such damages,ICI＇（Imperial Chemical Industries Ltd.） Mond Assessment and Fault Tree Analysis（FTA） are used to carry out hazard analysis.A series of hazard indices are calculated for the process unit on the basis of material factors,process hazards,and toxicities,etc.Offsetting factors for various forms of special protections are then applied and final adjusted values of these indices indicating the overall hazard rating of the unit are calculated.Then the minimal cut and radius sets are calculated by qualitative analysis.Furthermore,the critical importance of the basic events is calculated by quantitative analysis.Finally,the safety measures are put forward.The results of the investigation show that： the rank of the danger of the unit is medium category;air ingress at high temperature,valve failure and flange sealing failure are the most important three causes for such explosion incidents.So relative countermeasures are needed for management enhance on work safety,and controlling heating temperature and avoiding local heat accumulation in the reboiler can also lower the hazard class and ensure work safety.