注入温度对增强型地热系统性能的影响研究

基于考虑增强型地热系统(EGS)流体损失的三维传热传质数值模型,将热提取速率定义为与注入温度无关的函数,对比分析注入温度对以CO₂为工质的EGS(CO₂-EGS)和以水为工质的EGS(H2O-EGS)的性能的影响。结果发现:对于CO₂-EGS,较高的注入温度抑制热开采和CO₂损失(即CO₂封存);对于H2O-EGS,较高的注入温度促进热开采,同时导致较大的水损失。当热提取速率被大部分研究者定义为与注入温度相关的函数时,注入温度对CO₂-EGS和H2O-EGS的热开采性能的影响将分别被高估和低估。

STUDY ON IMPACT OF INJECTION TEMPERATURE ON PERFORMANCE OF ENHANCED GEOTHERMAL SYSTEMS

Based on a 3 D thermal-hydrologic numerical model considering fluid losses for enhanced geothermal systems(EGS),heat extraction rate is defined as a function independent of injection temperature,and the CO₂-EGS(EGS with CO₂as the working fluid)and the H2O-EGS(EGS with water as the working fluid)are compared for different injection temperatures. The results show that higher injection temperature restrains heat extraction and CO₂losses(i.e. CO₂sequestration)for the CO₂-EGS,and that higher injection temperature enhances heat extraction but leads to more water losses for the H2O-EGS. When heat extraction rate is defined by most researchers as a function dependent of injection temperature,the influence of injection temperature on heat extraction performance would be overestimated and underestimated for the CO₂-EGS and the H2O-EGS,respectively.