冷凝器换热管破裂超压分析及安全阀泄放量计算

Analysis of Distillation Overpressure for Condenser Tube Rupture and Calculation of PSV Relieving Flowrate

为得出冷凝器换热管破裂工况下安全阀泄放量的计算公式,在对蒸馏系统进行能量衡算,并对冷凝器换热管破裂超压工况进行讨论基础上,分析了此工况造成蒸馏系统超压不同情况。再沸器在冷凝器换热管破裂工况下比在正常工况下多输入系统的热量为Qnet;冷凝器换热管破裂进入系统的循环水被加热至泡点所需热量Qt;其被蒸发所需要消耗的总热量Qv。冷凝器换热管破裂,若循环水为重组分,系统不会超压。若循环水为轻组分:当Qnet≤Qt,安全阀不起跳;当Qt<Qnet≤Qv,不能被冷凝的水蒸气会通过安全阀泄放;当Qnet>Qv,部分工艺蒸汽及全部循环水产生的水蒸汽会通过安全阀泄放。

The specific scenario of distillation overpressure for condenser tube rupture is analysed.Based on the energy conservation of distillation system and discussion of condenser tube rupture scenario,formula of pressure safety valve(PSV)relieving flowrate is deducted.The excess heat input due to condenser tube rupture is Qnet.The duty heating the ejected cooling water to bubble point is Qt,and the duty evaporating the ejected cooling water is Qv.Hypothetically,cooling water is heavier than process fluid,PSV does not act.Hypothetically,cooling water is lighter than process fluid,for the first conditon that Qnet≤Qt,PSV does not act.For the second conditon that Qt<Qnet≤Qv,part of vapor comes from the evaporation of the ejected cooling water is relieved by PSV.For the third condion that Qnet>Qv,part of the process gas and all the vapor from cooling water evaporation are relieved by PSV.