压差发电技术在天然气浅冷处理中的应用探讨

Application of Differential Pressure Power Generation Technology in Shallow Cooling Treatment of Natural Gas

一些气质较贫的气田(即贫气气田)在前期开发中通常采用露点控制的浅冷处理工艺。天然气在浅冷处理中采用J-T阀进行节流制冷,至少有2.5~3.0 MPa的压力能浪费在J-T阀上。为充分利用天然气压力能、提高能量利用率,结合国内天然气压差发电技术及关键设备工业化应用现状,以新疆油田克拉美丽气田天然气浅冷处理装置为案例,开展压差发电技术在天然气浅冷处理装置的应用探讨,论证了天然气浅冷装置采用透平膨胀机发电的可行性。根据发电潜力计算,一套150×104m3/d浅冷装置采用透平膨胀机,利用湿气2.0 MPa压差发电,每小时净发电量可达350 kW·h,每年可发电280×104kW·h,节省电费109.2万元,项目投资估算总计400万元,静态投资回收期为3.6年。利用天然气浅冷处理过程中的压差进行发电,不仅可以充分利用天然气压力能,还可补充场站自身用电,具有良好的节能减排效果和示范效应,值得在石油天然气上游领域推广应用。

Some gas fields with lean gas(i.e.lean gas fields)usually use dew-point controlled shallow cooling process in early-stage development.During shallow cooling,the J-T valve is used for throttling refrigeration,and at least 2.5~3.0 MPa of pressure energy is wasted on the J-T valve.In order to make full use of the pressure energy of natural gas and improve energy utilization,this paper ex-plores the application of differential pressure power generation technology in the shallow cooling unit of natural gas based on the appli-cation of natural gas differential pressure power generation technology and the key equipment,taking the shallow cooling unit of Kela-meili Gasfield of Xinjiang Oilfield as an example.It also demonstrates the feasibility of using turbine expander to generate electricity in natural gas shallow cooling unit.The results show that:according to the calculation results of power generation potential,a 150×104 m3/d shallow cooling equipment can generate 350 kW·h per hour and 280×104 kW·h per year,saving 1.092 million yuan by using a turbine expander to generate electricity with the pressure difference of 2.0 MPa of wet gas.The total project investment is estimated to be 4 mil-lion yuan,and it can be paid back in 3.6 years.It is concluded that using the pressure difference in the shallow cooling process of natu-ral gas for power generation can not only fully utilize the pressure energy of natural gas,but also supplement the power supply for the site.It demonstrates good energy saving and emission reduction results and sets an excellent example,which can be promoted in the upstream oil and natural gas fields.