天然气脱水脱烃单元中多形态汞的分布模拟

Simulation on distribution of mercury speciations in natural gas dehydration and dehydrocarbon unit

在天然气处理过程中,汞会以单质汞、有机汞和无机汞的形态存在,为研究3种形态汞在脱水脱烃单元的分布规律,利用HYSYS软件对高含汞天然气脱水脱烃单元进行模拟,并探究汞质量浓度、不同形态汞的质量分数以及原料气气质组分对汞分布的影响。由结果可知:脱水脱烃流程对原料气中各形态的汞均有一定的脱除能力,其中对无机汞的脱除效果最好,质量分数99.9%的无机汞经过气液分离器以及浅冷分离器转移至废水。乙二醇溶液对不同形态汞有一定的吸收能力,原料气中质量分数53.1%的单质汞以及15.7%的有机汞转移至乙二醇富液中,随着重烃组分占比的增加,乙二醇溶液对汞的吸收能力降低,但凝析油和闪蒸气中汞流量大幅度上升。

Mercury exists in the speciations of elemental mercury,organic mercury and inorganic mercury during natural gas treatment.In order to study the distribution rule of the mercury in dehydration and dehydrocarbon unit,HYSYS software was used to simulate a high mercury-containing natural gas dehydration and dehydrocarbon unit.Influence of the mass concentration of mercury in feed natural gas,mass fraction of different speciations of mercury,and the composition of feed natural gas on the distribution of mercury were investigated.The results show that the dehydration and dehydrocarbon process has a certain removal capacity on elemental mercury,organic mercury and inorganic mercury in the feed gas,and the removal effect of inorganic mercury is the best.Inorganic mercury with a mass fraction of 99.9%is transferred to wastewater through gas-liquid separator and low temperature separator.Ethylene glycol solution has a certain absorption capacity to mercury of different forms.53.1%of elemental mercury and 15.7%of organic mercury in the feed natural gas are transferred to the ethylene glycol rich liquid.With the increase of the proportion of heavy hydrocarbon components,the absorption capacity of mercury in glycol solution decreases,but the mercury flow in the condensate oil and flash vapor increases significantly.