基于过程推动力模型的天然气净化用能分析

为了正确评价天然气净化过程能量利用状况及节能潜力,以火用分析为基础,基于过程推动力原理解析了天然气净化系统的用能过程,将天然气净化过程火用损失分为动量火用损失、传热火用损失和传质火用损失,从而建立起了天然气净化过程的能量结构模型。随后应用该模型对四川盆地普光气田高含硫天然气净化装置用能状况进行了分析,结果表明:①天然气净化系统的火用损失主要发生在传热过程和传质过程,其火用损失率分别为75.3%和20.1%;②传质过程的火用损失主要发生在胺液解吸再生过程,应用逐层塔板火用分析方法得知该过程的总火用效率约为10.0%,主要火用损失发生在重沸器和冷凝器中。最后,为了提高胺液解吸再生过程的用能效率,采用双效精馏工艺改造胺液解吸再生过程,通过高压塔顶气体与低压塔底物流进行换热,回收高压塔顶冷凝热量,降低低压塔底重沸器热量,使胺液解吸再生过程能耗降低了11.0%,火用效率提高了27.0%。

Energy analysis of a natural gas purification process based on the process driving model:A case history of the Puguang Gas Field,Sichuan Basin

In order to correctly evaluate energy utilization and energy saving potential in a natural gas purification process, we divided the exergy loss in the whole process into that of momentum, of heat and of mass transfer based on the process driving force, and thus established an energy structure model in the case of a purification plant in the Puguang Gas Field, Sichuan Basin. On this basis, we made an analysis which showed that both the heat and mass transfer process accounting for 75.3% and 20.1% respectively are the most exergy loss process in this plant. Because the exergy loss in the mass transfer process mainly occurs in the amine regeneration process, the method of plate to plate exergy analysis was applied to calculate the cumulative exergy efficiency of amine regeneration process of about 10.0%, and also found that the main exergy loss occurred in the reboiler and condenser. With the introduction of double effect distillation into the amine regeneration process, the heat exchange was done between the overhead high pressure gas and the low pressure bottom stream to recover the overhead high pressure condensing heat, and reduce the energy needs for the low pressure bottom reboiler. The results showed that the application of double effect distillation helped not only reduce the energy consumption of the amine regeneration process by 11.0% but increase the exergy efficiency of this plant by 27.0%.