风速和泄漏速率对碳酰氯泄漏扩散危害空间的影响

目的建立某化工厂TDI生产泄漏事故的计算流体动力学(CFD)模型,减少甲苯二异氰酸酯(TDI)生产过程中碳酰氯泄漏造成的危险。方法研究环境风速和泄漏速率对碳酰氯阈浓度和致死浓度危害三维空间范围的影响,利用结果数据拟合了两种因素共同作用下阈浓度云团危害空间的快速估算式。结果模拟结果显示风速增大,阈浓度和致死浓度云团危害范围均减小,且风速从1.5 m/s增大到4.5 m/s,阈浓度云团危害范围减半,阈浓度云团危害长度远大于宽度和高度;泄漏速率增大,阈浓度和致死浓度云团危害范围均呈线性增长;最不利条件下,泄漏速率分别为0.018 kg/s、0.031 kg/s、0.045 kg/s时,阈浓度云团危害长度刚好到达下风向1 000 m、1 500 m、2 000 m安全防护距离的位置;对于一般规模的泄漏事故,致死浓度云团不会危害到厂区以外。结论研究结果可为碳酰氯泄漏事故应急救援提供理论和数据支持。

Influence of wind speed and leakage rate on the damage space of carbonyl chloride leakage and diffusion

  Objective  In order to reduce the dangerous consequences caused by carbonyl chloride leakage during TDI production, a computational fluid dynamics (CFD) model of production leakage accident in a TDI chemical plant was established.  Methods  The effect of both wind speed and leak rate on the three-dimensional damaging range of threshold concentration and lethal concentration was analyzed, and its result data was used to fit the fast estimation formula of damage space of threshold concentration cloud under the combined influence of these two factors.  Results  The simulation results showed that the harmful range of threshold concentration and the lethal concentration cloud decreased with the increase of the wind speed. The harmful range of threshold concentration cloud decreased by half with wind speed increasing from 1.5 m/s to 4.5 m/s. The damaging length of threshold concentration cloud was much greater than the width and height. Under the most unfavorable conditions, the damaging length of the threshold concentration cloud just may reach the position of the downwind protection distance of 1 000, 1 500 and 2 000 m when the leak rate was 0.018, 0.031 and 0.045 kg/s, respectively. With the increase of leakage rate, both the damaging range of threshold concentration and the lethal concentration cloud could increased in way of linear growth. For a leakage accident of usually normal scale, the lethal concentration cloud would not harm outside the plant.  Conclusion  Exploring the three-dimensional damaging space can provide theoretical and data support for the emergency rescue of carbonyl chloride leakage accidents.