Construction modeling and parameter optimization of multi-step horizontal energy storage salt caverns. (15th July 2020)

• Record Type: Journal Article
• Authors: Li, Jinlong; Shi, Xilin; Zhang, Shuai
• Is Part Of: Energy. Volume 203(2020)
• Publication Date: 2020-07-15
• Subjects: Bedded salt rock -- Energy storage salt cavern -- Multi-step leaching -- Cavern construction -- Horizontal salt cavern; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2020.117840
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: A multi-step horizontal leaching method can be used to efficiently construct energy storage salt caverns. However, the modeling and control of a multi-step horizontal cavern are complicated and have been investigated little, resulting in many collapses of such caverns. To predict the 3-D development of a horizontal salt cavern during construction, a numerical model is proposed based on a composite structural mesh. The salt dissolution rate is introduced as being related to the brine concentration. The flow/concentration fields are dynamically divided into four subareas. Their governing equations are derived based on mass and volume conservation. The accumulation and re-distribution of the insoluble substances are considered. A C++ program is developed for model implementation. The feasibility and accuracy of the model are verified by comparisons with data in published literature. A series of simulations have been conducted for technological parameter optimization. Results show that using a larger borehole length increases cavern capacity. Using a larger step distance increases the construction control but decreases the cavern capacity. Using a larger flow rate increases construction efficiency but decreases the energy-saving coefficient and construction control. A long borehole length, a medium step distance and a variable flow rate are suggested for horizontal cavern construction. Highlights: A model is presented for the construction of a multi-step horizontal salt cavern. A composite structural mesh is proposed to describe the boundary movements. A dynamic zoning model is proposed for the flow/concentration field. A series of simulations are conducted for parameter optimization. A long borehole length, medium step distance and dynamic flow rate are suggested.