Optimization of working fluid for U-shaped well supercritical power generation system driven by hot dry rock

doi:10.16085/j.issn.1000-6613.2024-1056

Chemical Industry and Engineering Progress ›› 2025, Vol. 44 ›› Issue (9): 4945-4953.DOI: 10.16085/j.issn.1000-6613.2024-1056

• Energy processes and technology • Previous Articles

Optimization of working fluid for U-shaped well supercritical power generation system driven by hot dry rock

SUN Bin¹^,²^,³^,⁴(), DU Jianguo⁵^,⁶, WANG Lingbao¹^,²^,³^,⁴, BU Xianbiao¹^,²^,³^,⁴, GONG Yulie¹^,²^,³^,⁴, LI Huashan¹^,²^,³^,⁴()

^1.School of Energy Science and Engineering, University of Science and Technology of China, Guangzhou 510640, Guangdong, China
^2.Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, Guangdong, China
^3.CAS Key Laboratory of Renewable Energy, Guangzhou 510640, Guangdong, China
^4.Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, Guangdong, China
^5.Geological Survey of Jiangsu Province, Nanjing 210018, Jiangsu, China
^6.Natural Resources Carbon Neutralization Engineering Research Center of Jiangsu Province, Nanjing 210018, Jiangsu, China

Received:2024-07-01 Revised:2024-10-17 Online:2025-09-30 Published:2025-09-25
Contact: LI Huashan

U型井干热岩超临界发电系统工质优选

孙斌¹^,²^,³^,⁴(), 杜建国⁵^,⁶, 王令宝¹^,²^,³^,⁴, 卜宪标¹^,²^,³^,⁴, 龚宇烈¹^,²^,³^,⁴, 李华山¹^,²^,³^,⁴()

^1.中国科学技术大学能源科学与技术学院，广东广州 510640
^2.中国科学院广州能源研究所，广东广州 510640
^3.中国科学院可再生能源重点实验室，广东广州 510640
^4.广东省新能源和可再生能源研究开发与应用重点实验室，广东广州 510640
^5.江苏省地质调查研究院，江苏南京 210018
^6.江苏省自然资源碳中和工程研究中心，江苏南京 210018

通讯作者: 李华山
作者简介:孙斌（1999—）男，硕士研究生，研究方向为地热能利用技术。E-mail：binsun@mail.ustc.edu.cn。
基金资助:
江苏省碳达峰碳中和科技创新专项(BE2022859)

Abstract

Abstract:

U-shaped well supercritical cycle power generation technology is considered as an important way to develop dry hot rock, and the circulating working fluid is one of the important factors affecting power generation performance. Regarding this problem, a numerical model of U-shaped well supercritical power generation system with dry hot rock was established. The potential application of seven refrigerants as circulating working fluids in U-shaped well supercritical power generation systems was analyzed, and the influence of fluid flow rate, vertical well depth, horizontal well length, geothermal gradient, and rock thermal conductivity on the power generation capacity and economic performance of the system were studied. The results were compared with those of CO₂, aiming to select the ideal circulating working fluid. In the analysis, average annual power generation and levelized cost of energy are selected as performance indicators. Results indicate that when the operating conditions change, the variation regular of the annual power generation of different working fluids is very similar, and the variation of the levelized cost of energy is different. Of the seven alternative fluids, R152a and R143a performs better than CO₂. R152a, which has a relatively large annual power generation and a small levelized cost of energy, is considered as an ideal circulating working fluid.

Key words: supercritical fluid, U-shaped well, closed loop geothermal system, geothermal power generation, circulating working fluid, heat transfer

摘要：

U型井超临界循环发电技术是开发干热岩的重要途径，其中循环工质是影响系统性能的重要因素之一。本文建立了U型井干热岩超临界发电系统模型，分析了7种制冷剂作为U型井超临界发电系统循环工质的应用潜力，研究了流体流量、垂直井深度、水平井长度、地温梯度和岩石热导率对系统发电能力和经济性能的影响规律，并将所得结果与CO₂进行对比，旨在选择出理想的循环工质。选用的性能指标为年均发电量和平准化度电成本。结果表明，工况条件发生变化时，不同工质年均发电量的变化规律非常相似，平准化度电成本则表现出不同的变化情况，7种备选流体中，R152a和R143a的性能表现优于CO₂，R152a在所研究的工况范围内具有更大的年均发电量和更小的平准化度电成本，是一种较为理想的循环工质。

关键词: 超临界流体, U型井, 闭式地热系统, 地热发电, 循环工质, 传热

CLC Number:

TM616

SUN Bin, DU Jianguo, WANG Lingbao, BU Xianbiao, GONG Yulie, LI Huashan. Optimization of working fluid for U-shaped well supercritical power generation system driven by hot dry rock[J]. Chemical Industry and Engineering Progress, 2025, 44(9): 4945-4953.

孙斌, 杜建国, 王令宝, 卜宪标, 龚宇烈, 李华山. U型井干热岩超临界发电系统工质优选[J]. 化工进展, 2025, 44(9): 4945-4953.

Figures/Tables 15

References 34

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流体	文献	T_his/℃	M_hs/kg·s^-1	p_h/MPa	T_hso/℃	T_cso/℃	W_net/kW	η_t/%
R134a	本文	150	0.1	5.586	70.3	17.2	4.750	14.096
	文献[32]	150	0.1	5.586	70.3	17.2	4.7	14.0
R152a	本文	150	0.1	5.008	87.6	17.1	3.957	14.952
	文献[32]	150	0.1	5.008	87.6	17.1	4.0	14.9
R1234yf	本文	150	0.1	4.962	52.8	17.4	5.303	12.938
	文献[32]	150	0.1	4.962	52.8	17.4	5.3	12.9
R1234ze	本文	150	0.1	4.72	78.4	17.3	4.301	14.190
	文献[32]	150	0.1	4.72	78.4	17.3	4.3	14.1

流体	文献	T_his/℃	M_hs/kg·s^-1	p_h/MPa	T_hso/℃	T_cso/℃	W_net/kW	η_t/%
R134a	本文	150	0.1	5.586	70.3	17.2	4.750	14.096
	文献[32]	150	0.1	5.586	70.3	17.2	4.7	14.0
R152a	本文	150	0.1	5.008	87.6	17.1	3.957	14.952
	文献[32]	150	0.1	5.008	87.6	17.1	4.0	14.9
R1234yf	本文	150	0.1	4.962	52.8	17.4	5.303	12.938
	文献[32]	150	0.1	4.962	52.8	17.4	5.3	12.9
R1234ze	本文	150	0.1	4.72	78.4	17.3	4.301	14.190
	文献[32]	150	0.1	4.72	78.4	17.3	4.3	14.1

流体	临界压力/MPa	临界温度/℃	全球变暖潜值
CO₂	7.377	31.10	1
R134a	4.059	101.06	1410
R143a	3.761	72.71	4410
R152a	4.52	113.26	122
R1234ze	3.634	109.37	<1
R227ea	2.925	101.75	3140
R125	3.618	66.03	3450
R1234yf	3.382	94.70	<1

流体	临界压力/MPa	临界温度/℃	全球变暖潜值
CO₂	7.377	31.10	1
R134a	4.059	101.06	1410
R143a	3.761	72.71	4410
R152a	4.52	113.26	122
R1234ze	3.634	109.37	<1
R227ea	2.925	101.75	3140
R125	3.618	66.03	3450
R1234yf	3.382	94.70	<1

参数	值	参数	值
岩石密度/kg·m^-3	2200	水平井长度/m	6000
岩石热容/J·kg^-1·K^-1	850	地温梯度/K·km^-1	40
岩石热导率/W·m^-1·K^-1	3	注入压力/MPa	20
地面温度/℃	25	质量流量/kg·s^-1	45
管道内径/mm	142.9	冷凝温度/℃	25
垂直井深度/m	6000	泵和膨胀机的等熵效率/%	80

Optimization of working fluid for U-shaped well supercritical power generation system driven by hot dry rock

U型井干热岩超临界发电系统工质优选

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References 34

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