The carbon dioxide (CO) geological storage is an effective technology for the carbon emission reduction, but the high-priced sequestration has become the main factor restricting the development. Meanwhile, surface waste heats are difficult to be effectively utilized, and energy supply and demand have been unbalanced for a long time. In order to solve the above problems, this study proposed an integrated system in accordance with the concept of the carbon capture, utilization and storage (CCUS) technology, realizing the aquifer storage of heats and CO at the same time. Based on the numerical model considering the gas–water dissolution, CO saturation distributions, temperature distributions and well performances of the integrated system were analyzed. The CO storage performance and heat extraction performance of the integrated system were quantitatively evaluated. Furthermore, economic performances and applicabilities of closed-loop and open-loop systems were compared and discussed. The results show that variations of CO solubility and physical properties constitute a complex coupling process between the heat storage and CO sequestration in the integrated system. The CO migration radius during the high-temperature injection is reduced by 13 % compared with the case without considering the heat storage. In an underground space of approximately 5.76 × 10 m, CO storage capacities of closed-loop and open-loop systems during the injection period are 11.935 Mt and 5.741 Mt with effective storage ratios of 97.5 % and 93.2 %, respectively. The open-loop system enhances the carbon sequestration ability of the integrated system because of a fewer proportion of free gas. Thermal performances of the closed-loop system are much weaker than that of the open-loop system, thus showcasing a poor heat extraction economic performance. After 20 years, closed and open systems can offset part of CO storage costs with $4998.8 and $576973.5, respectively. According to outlet temperature differences, the closed-loop system can be used for the high temperature reservoir reconstruction and the district heating with the main purpose of CO storage, while the open-loop system is suitable for the seasonal underground heat storage, central heating system and even geothermal power generation with the main purpose of CO utilization. This study provides a new path for the carbon capture, utilization and storage technology.

中文翻译：

---

CO2地质封存与含水层热能储存一体化系统：储存特性及适用性分析


二氧化碳地质封存是一种有效的碳减排技术，但高昂的封存成本已成为制约其发展的主要因素。同时，地表余热难以有效利用，能源供需长期不平衡。为了解决上述问题，本研究提出了一种按照碳捕获、利用和储存（CCUS）技术概念的集成系统，同时实现了热量和二氧化碳的含水层储存。基于考虑气水溶解的数值模型，对集成系统的CO饱和度分布、温度分布和井动态进行了分析。对集成系统的二氧化碳存储性能和排热性能进行了定量评估。此外，还对闭环和开环系统的经济性能和适用性进行了比较和讨论。结果表明，CO 溶解度和物理性质的变化构成了集成系统中储热和 CO 封存之间的复杂耦合过程。与不考虑蓄热的情况相比，高温注入过程中CO的迁移半径减小了13%。在约5.76×10 m的地下空间中，注入期间闭环和开环系统的CO封存量分别为11.935 Mt和5.741 Mt，有效封存率分别为97.5 %和93.2 %。开环系统由于游离气体比例较少，增强了集成系统的碳封存能力。 闭环系统的热性能远弱于开环系统，因此排热经济性较差。 20年后，封闭式和开放式系统可以分别抵消部分二氧化碳封存成本4998.8美元和576973.5美元。根据出口温差，闭环系统可用于高温水库改造和以CO储存为主要目的的区域供热，开环系统适用于季节性地下蓄热、集中供热系统甚至以二氧化碳利用为主要目的的地热发电。该研究为碳捕获、利用和封存技术提供了一条新途径。