四川盆地页岩气开发地面工程多采用三甘醇(TEG)脱水工艺脱除原料天然气中的饱和水,以满足管输要求。现场运行数据表明,前期建设的页岩气脱水装置能耗相对较高。为降低页岩气脱水装置能耗,以处理规模300×104 m3/d的装置为例,借助ASPEN HYSYS V11.0模拟软件,选用CubicPlusAssociation(CPA)物性包,并结合现场实际运行情况,对页岩气脱水装置的原料气进气温度、TEG循环量、重沸器再生温度、TEG贫液质量分数进行优化研究。研究结果表明:1)在进气温度为35 ℃、TEG循环量为2.5 m3/h、重沸器再生温度为203 ℃、TEG贫液质量分数为99.2%的条件下,装置在产品干气满足管输要求的同时,节能效果明显,单位产品综合能耗降低了42.1%;2)经优化后,单套TEG脱水装置的工程投资降低了16.4%,可节省约230万元;3)与现有装置相比,单套装置节约用气27.4×104 m3/a,节约用电5.3×104 kW·h/a,全年可节省运行费用约30.1万元。结论认为,研究成果可以为页岩气脱水装置的设计及优化提供参考。

In the surface facilities engineering of shale gas development in Sichuan Basin, dehydration process by triethylene glycol (TEG) is most frequently used to remove the saturated water in raw natural gas to meet the pipeline transportation requirements. The field operation data shows that the energy consumption of the shale gas dehydration unit constructed in the early development stage is relatively high. In order to reduce the energy consumption of the shale gas dehydration unit, taking a 300×10⁴ m³/d(3×10⁶ m³/d) unit as an example, the feed gas inlet temperature, TEG circulation rate, regeneration temperature and lean TEG concentration of the shale gas dehydration unit are optimized. ASPEN HYSYS simulation software with the Cubic-Plus-Association (CPA) Property Package is used in this research, making use of the site operating conditions. The result shows that: 1) under the conditions of feed gas inlet temperature of 35 ℃, TEG circulation rate of 2.5 m³/h, regeneration temperature of 203 ℃, lean TEG concentration of 99.2%, treated product gas meets the requirements of pipeline transportation, and the energy conservation effect of this optimum operating conditions is obvious, as the comprehensive energy consumption for unit output of product is reduced by 42.1%; 2) after optimization, the capital cost of a single set of TEG dehydration unit has been reduced by 16.4%, saving about 2.3 million RMB; 3) compared with the current facilities, each single set of TEG dehydration unit can save 27.4×10⁴ m³/a(274×10³ m³/a) gas and 53×10³ kW·h/a(5.3×10⁴ kW·h/a) electricity, amounting to about 0.301 million RMB of annual operating cost saving. In conclusion, the research result can provide good reference for the design and process optimization of shale gas TEG dehydration unit.