输气站场过滤分离器压降与除尘效率变化特性

Change characteristics of pressure drop and collection efficiency of the filter separators in the gas transmission station

为通过压降来评价不同工况下过滤分离器的除尘效率和工作状况,指导现场过滤分离器滤芯的操作和更换,本文以输气站场典型卧式过滤分离器为研究对象,采用粉尘在线检测和计算流体力学(CFD)数值模拟的方法,分析不同运行时间、运行压力下过滤分离器压降和除尘效率的静态与动态特性,并通过现场实际验证。结果表明:在相同标况流量下,操作压力越低,过滤分离器初始压降越高;随着过滤分离器的运行时间增长,其压降检测值将偏离拟合的最优二次曲线,其除尘效率也将呈下降趋势,特别是在运行压力较低时下降更快,其根源在于低压下气流速度快,可携带更多已聚结的颗粒流出,致使下游粉尘浓度上升;CFD方法预测与在线检测的除尘效率误差均低于20%,现场实际除尘量证实两种方法均有较高的准确性与可靠性,且适合过滤分离器压降与除尘效率变化的预测。

The typical horizontal filter separator in the gas station was taken as the subject to evaluate the collection efficiency and working status of the filter separators through their operational pressure-drops under different operating conditions and guide their field operation and replacement of their filter elements.The dust on-line detection technique and CFD simulation were adopted to analyze the static and dynamic characteristics of pressure drop and collection efficiency of filter separator under different running time and pressure.The major results were verified using actual values.The results indicate that the lower of initial pressure-drop of the filter separator,the lower of operating pressure at the same flow rate.With the increase of its operational time,a strong trend of the monitored pressure-drop values is negatively deviating their best-fitted curves,and its collection efficiencies also present a decreasing trend,especially at its lower operational pressure,due to the gas with higher flow velocity carrying more coalesced particles to the downstream and leading to the increase of downstream dust concentration at this operational condition.The errors of collection efficiencies obtained by the on-line particle monitoring technique and the CFD method are lower than 20%.The actual dust collection verified that both methods are of higher accuracy,reliability and suitable in the prediction on the evolution of the pressure drop and the collection efficiency.