在“双碳”目标背景下，探索重排行业减碳增效新路径，发展CO2高能利用新质生产力是CO2减排研究的热点问题。为确定CO2相变致裂机制，扩展CO2相变致裂工程应用，基于CO2多相态变化特性及能源利用方面表现出的安全环保优势，提出一种新型深地钻孔超临界CO2换热器。以25℃条件下CO2为研究对象，采用流体仿真设计了不同水温作为载热流体的模拟方案，揭示了水热流体与CO2耦合作用下的气-水传热机理，通过试验分析验证了CO2换热器传热的可靠性。研究表明，随着水温增加，CO2升温速率与水热流体温度呈正相关，水温每升高1℃，CO2温度升高0.9℃，水温随着CO2吸热量的增加逐渐降低，水热流体的耗散温度与CO2吸热温度成正比；水热流体传热系数由1790W/m2?K增加至2090W/m2?K，水热流体的传热系数随初始水温增加逐渐增大，CO2传热系数与水热流体的传热系数成正比；CO2相变吸热温度随水温增加呈指数型增长趋势，液态CO2传热系数与气体CO2传热系数变化趋势成反比；管内CO2最大压力由131MPa增加至199MPa，压力变化经历了液态CO2吸热膨胀阶段、气态CO2吸热膨胀阶段、相变增能阶段以及压力平稳阶段；CO2吸热量与初始水温呈正相关，水流热源功率随着水温的升高逐渐增大，水流热源功率与水温呈正比。通过建立关联式和试验分析验证了深地钻孔超临界CO2换热器的有效性，研究为超临界CO2换热器的设计提供了依据。

Under the background of the “dual carbon” target, exploring new paths for industry restructuring to reduce carbon emissions and increase efficiency, and developing new high-quality productivity for CO2 high-energy utilization are hot topics in CO2 emission reduction research. To determine the mechanism of CO2 phase change induced cracking and expand the application of CO2 phase change induced cracking engineering. Safety and environmental advantages demonstrated based on the multiphase change characteristics of CO2 and energy utilization, a new type of deep drilling supercritical CO2 heat exchanger is proposed. Taking CO2 at 25 ℃ as the research object, a simulation scheme was designed using fluid simulation to simulate different water temperatures as heat carrying fluids, revealed the gas-water heat transfer mechanism under the coupling effect of hydrothermal fluid and CO2.The reliability of heat transfer in CO2 heat exchangers has been verified through experimental analysis. The results that as the temperature of the hydrothermal fluid increases, the heating rate of CO2 is positively correlated with the temperature of the hydrothermal fluid. For every 1℃ increase in water temperature, the temperature of CO2 increases by 0.9℃, the temperature of the water stream decreases gradually with the increase of CO2 heat absorption, dissipation temperature of hydrothermal fluids is proportional to CO2 absorption temperature. The heat transfer coefficient of hydrothermal fluids increases from 1790W/m2?K to 2090W/m2?K. The heat transfer coefficient of hydrothermal fluids gradually increases with the increase of initial water temperature, The heat transfer coefficient of CO2 is directly proportional to the heat transfer coefficient of hydrothermal fluids. The CO2 phase change heat absorption temperature showed an exponential growth trend with the increase of water temperature, and the liquid CO2 heat transfer coefficient was inversely proportional to the trend of the gas CO2heat transfer coefficient. The maximum pressure of CO2 inside the pipe increased from 131MPa to 199MPa, the pressure change goes through a phase of thermal expansion of liquid CO2, a phase of thermal expansion of gasCO2 a phase of phase change energization, and a phase of pressure stabilization. The heat absorption of CO2 is positively correlated with the initial water temperature, and the power of the water flow heat source gradually increases with the increase of water temperature. The power of the water flow heat source is proportional to the water temperature. The effectiveness of the deep drilling supercritical CO2 heat exchanger was verified through the establishment of correlation equations and experimental analysis, providing a basis for the design of supercritical CO2 heat exchangers.

霍英东教育基金项目（71076）；陕西省自然科学基础研究计划项目（2019JLP09）；新疆生产建设兵团重点领域科技攻关计划项目（2019AB001）