Sandstone geothermal tail water economic recharge system

Abstract

The invention relates to a geothermal tail water recharge technology in geothermal exploitation and utilization process. Besides a geothermal well, the overall system mainly adopts geothermal water desanding devices, sub-catchments, a heat exchange device, frequency conversion pressurizing devices, a degassing device, a tail water filter and an electric control valve. Through the adjustment of the system, functions of the exploitation and the recharge of the geothermal well are converted, cumulative blockade caused by long term recharge of a simple opening geothermal well is eliminated, and the chronicity of the recharge is ensured; through the adoption of a standby filter, the sustainability and the continuity of the recharge process are ensured; three-level filters with different precisions are coordinated and adopted, besides, PID control with an automatic regulatory function and enabling the overall system to realize automatic frequency rising and lowering of pressure pumps and opening degree of the electric control valve is designed, and mutual interference between exploitation and recharge of the geothermal well is eliminated. The system is suitable for sandstone stratums in various areas, through the adoption of the system, economical and effective recharge can be conducted on tail water after the geothermal comprehensive utilization, and sustainable development of geothermal exploitation and utilization can be ensured.

Description

technical field [0001] The invention belongs to the field of geothermal development and utilization, and in particular relates to sandstone geothermal tail water recharge. technical background [0002] As a renewable energy source, geothermal resources have been included in the "Twelfth Five-Year Plan" energy plan. How to make good use of geothermal resources is one of the ideal choices for energy saving and emission reduction. [0003] Geothermal water is mined from the formation to the ground for heat exchange and utilization. The temperature, pressure and other working conditions of the geothermal water change, and the composition of the geothermal water changes after contact with the air. Blockages of different origins were formed, resulting in a decrease in the recharge flow rate of the geothermal tail water in the sandstone thermal storage, a decrease in the recharge efficiency, and even failure to recharge. [0004] The existing refilling device basically consists o...

AI Technical Summary

Problems solved by technology

On the whole, the currently used recharge devices mainly have the following characteristics: (1) They are all two-stage filtration, and the precision setting span of the front and back stages is too large. Such facilities are likely to cause excessive workload of the filter during operation; on the other hand, despite the filtration, after a long period of recharge, the recharge well will also be clogged to varying degrees, resulting in reduced recharge efficiency

(2) The recharging device failed to consider the design of the entire system from mining to recharging, resulting in mutual interference in the hydraulic conditions of the pipeline

(3) During the use of the quartz sand tank filter device, geothermal water with high salinity and complex composition is likely to cause agglomeration, which will reduce the filtering effect and is not easy to clean

The nitrogen protection device and the quartz sand tank occupy too large an area, so it is not easy to promote and use it on a large scale

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