尿素合成塔内化学爆炸机理分析  

Theoretical analysis on the urea reactor explosion accidents

作　　者：李冬[1] 陶刚[1] 张礼敬[1] 许丹枫[1] 

机构地区：[1]南京工业大学城市建设与安全工程学院,南京21009

出　　处：《安全与环境学报》2011年第2期191-195,共5页Journal of Safety and Environment

基　　金：国家863项目(2007AA06A402)

摘　　要：分析了尿素合成塔发生化学爆炸的可能性。利用经验公式计算出塔内上部空间气相在正常生产和非正常生产状态下的爆炸极限范围,并计算出非正常生产状态下气相化学爆炸产生的压力和能量范围。计算结果与现场数据吻合。爆炸所产生的压力作用于液面上,根据静压传递原理,尿液内各点与外压相等,超过尿塔正常工作压力,并导致破裂。This paper intends to take as its two case study samples the two serious urea reactor explosion accidents that took place at home, which brought about heavy casualty and economic damage of similar nature. Thus, our analysis has been done in terms of three key elements of chemical explosions and their aftermath consequences. The analyses of the explosion process indicate that the flammable gases were found including hydrogen, ammonia and methane mixed with oxygen and inert gases, such as nitrogen, vapor and carbon dioxide in the gas phase of urea reactor. The impact friction, adiabatic compression, static and spontaneous combustion of such gases were found to be the ignition sources as the result of the analysis. Empirical equations were also used to confirm the explosion limit under the condition of high temperatures and high pressures. Moreover, conditions of inert gas presence was also taken into account. Everything considered, the explosion limit of mixed gases was found to be 11.27%-78.94% under the normal production conditions. And the practical mixed gas concentration was found to be 92.19%, far above the explosion maximum limit. On the other hand, if the temperature decreased and the pressure remained in the maintenance range, and if the practical mixed gas concentration was within the explosion limit, it would also be possible to cause chemical explosions. When the urea reactor were shut down with its pressure maintained and the thermos level dropping, the volume of the gas phase would be likely to approach 3.7 m^3. The constraint conditions were possible to be determined in accordance with the practical situation by calculating the range of inequality. And, next, we have determined the pressures and energies released in the two explosion accidents by using a software named Lingo. The calculation results we have gained prove to be in accord with the spot-gained statistics, which confirms the probabilities of the chemical explosions. Quoting the static pressure transmission principle, we have deduced that

关 键 词：安全工程 尿素合成塔 化学爆炸 爆炸极限 压力和能量范围 

分 类 号：X937[环境科学与工程—安全科学]