RENEWABLE ENERGY
·
2024
·
IF 9
Yichao An,Fang Zhou,Yu Shi,Liang Zhang,Jun Li,Yu Hou,Xun Zhu,Qiang Liao
Low-temperature geothermal energy (<150 °C) is an abundant green renewable energy and non-aqueous thermally regenerative flow batteries hold immense potential for converting it into electricity. In this study, a reduced graphene oxide-modified nickel foam (RGO/NF) was developed to promote the battery performance. It was demonstrated that the low-cost nickel foam with extensive optimization potential was the desired substitute for the traditional reticulated glass carbon electrode, with a similar maximum power density (105.7 W/m 2 ). With acid treatment, a relatively rough surface with increased specific surface area was obtained, resulting in an improved performance of the battery. According to the density functional theory results, the modification of RGO on NF provided a strong microscopic interaction with Cu, accompanied by more active sites and improved wettability. Therefore, the maximum power density of the battery was increased by 21 %, while the capacity was extended by 100 % and the energy density was improved by 165 %, compared to the battery with NF. To further improve the battery performance, the flow rate and mass fraction of nano copper were optimized, exhibiting the optimal values of 35 mL/min and 15 %, respectively. The present results were competitive and helpful for future application of this technology for low-temperature geothermal energy recovery.
CAS / MDL:
研究领域:
能源材料科学
·
电化学工程
✓ 已验证
产品关联
DOI
高影响因子
Scientific Reports
·
2025
·Vol. 15
·期 1
·1-19
·
IF 3.9
Zhu Wenxi,Wang Bingjie,Cui Shengkai,Wang Jing,Tan Huijing
Effective heat transfer between the working fluid and subterranean rocks is essential for producing green and low-carbon geothermal energy. As the primary thermal conductive medium, cement has low thermal conductivity, leading to high thermal resistance and significantly reducing geothermal wells’ efficiency. Therefore, high thermal conductivity cement has emerged as a widely anticipated new research area. The purpose of this research is to address the substantial harm of traditional carbon-based thermal conductive fillers to cement. A novel expanded graphite (EG)/epoxy resin (EP) composite additive (MEG) was designed to increase cement’s thermal conductivity while preserving its mechanical strength and pumpability. Firstly, the physicochemical properties of MEG were revealed by FT-IR, UV-Vis, SEM, and TGA. Then, the applicability of MEG cement in adverse geological environments (high-temperature 60–100 ℃, high-mineralization 5–36% NaCl) was evaluated through simulated maintenance experiments. Finally, the hydration products and pore structure of MEG-cement were analyzed by XRD/FT-IR and SEM/MIP, revealing the thermal conductivity enhancing mechanism. The results showed that: 1) MEG uses ZDMA as a bridge to promote the ring opening and curing of EP, and is formed by strong cation -π interaction with EG. 2)After curing at 60–100 ℃, MEG-cement exhibits a significant increase (46.6-182.1%) in thermal conductivity within the optimal dosage range of 5–10%, fully meeting the requirements for compressive strength (10.4–21.7 MPa) and fluidity (19.3–21.2 cm) of cementing. In addition, MEG-cement maintained stable density and significant high thermal conductivity advantage in high-mineralization environments (5–36% NaCl), with an increase in thermal conductivity of 23.8- 54.1%. 3) The mechanism of MEG promoting heat transfer in cement is summarized as the enhancement of the hydration process and the production of C-S-H gels. C-S-H gels filled the gel pores and transition pores in the cement skeleton and formed a dense, high thermal conductivity network, which shortens the heat transfer path and thus greatly improves the thermal conductivity of cement. In summary, this study has successfully developed a MEG geothermal cement with independent intellectual property rights that provides reliable technical support for the efficient development of geothermal resources and has important engineering application value.
研究领域:
能源工程
·
材料科学
·
石油工程
·
热科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2025
·
IF 3.7
Shuai Li,Yongli Ma,Baixu Cao,Mingyan Liu
Geothermal energy is a crucial renewable resource for achieving carbon neutrality. However, its exploitation is hampered by scaling, particularly calcium carbonate (CaCO 3 ) deposition in wellbores. To address this, a novel composite polymer scale inhibitor was synthesized via the copolymerization of five monomers: acrylic acid, hydroxyethyl methacrylate, sodium allyl sulfonate, citric acid, and monosodium glutamate. This molecular design enables the synergistic integration of multiple functional groups (carboxyl, sulfonic, hydroxyl, ester, and amide). Fourier transform infrared spectroscopy confirmed the successful incorporation of these groups, and thermogravimetric analysis demonstrated excellent thermal stability. Evaluation experiments revealed that the copolymer serves as a highly effective scale inhibitor under simulated high-temperature geothermal conditions (150–200 °C), achieving an inhibition rate exceeding 96% against CaCO 3 scaling. This work presents a promising and sustainable solution for scaling control in challenging geothermal environments.
研究领域:
地热能
·
材料科学
·
阻垢技术
·
高分子化学
✓ 已验证
DOI
高影响因子
APPLIED THERMAL ENGINEERING
·
2025
·
IF 6.9
Maoyan Xu,Xianyu Yang,Ren Wang,Jiwei Song,Jianlong Wang,Jingyu Xie,Lei Zhang,Zhaokai Dai,Jihua Cai,Guosheng Jiang
In the process of geothermal energy exploitation, an important factor restricting the development of geothermal energy is the low efficiency of convective heat transfer between circulating mediums, such as water and glycol with high-temperature rocks, which results in low energy utilization of geothermal resources. Nanofluids have a broad application prospect in the field of geothermal reservoir heat transfer due to their excellent heat transfer performance and high specific surface area. Currently, there is a lack of in-depth research on the application of nanofluids in the field of geothermal energy, especially in dry-heat rock geothermal reservoirs. The research on contact heat transfer of nanofluids with different shape of nanoparticles needs to be strengthened. In this paper, Al 2 O 3 nanoparticles are selected and classified as sheet-like, rod-like and near-spherical according to the size of the specific surface area of the nanoparticles. The optimal mass ratio of dispersant to nanoparticles was optimized through systematic testing experiments, among which the optimal dispersant mass ratios corresponding to rod-like, sheet-like and near-spherical nanoparticles were 5:2, 5:4 and 10:1, respectively. The thermal conductivity and specific heat capacity of the nanofluids corresponding to the three nanoparticle shapes at different mass fractions were measured, and the optimal mass fractions of nanoparticles were preferred to be 2 wt%. Subsequently, the contact convective heat transfer characteristics between the nanofluids and high-temperature granite were tested and analyzed. The results show that the shape of nanoparticles affects the degree of enhanced heat transfer of nanofluids, in which the larger the specific surface area of nanoparticles, the higher the degree of enhanced heat transfer of nanofluids. When the Reynolds number is 2000, the heat transfer coefficients of the nanofluids containing sheet-like nanoparticles are increased by 7.4 % and 18.5 %, and the heat transfers by 5.3 % and 13.3 %, respectively, compared to the nanofluids containing rod-like and near-spherical nanoparticles. When the Reynolds number was increased to 6000, the heat transfer coefficients increased by 9.7 % and 22.5 % and heat transfer increased by 5.5 % and 10.6 %, respectively. In addition, the effect of nanofluids on the local heat transfer intensity in the flow channel is also investigated in this paper. At the highest point of heat transfer intensity in the flow channel, the nanofluid containing sheet-like nanoparticles increased the heat transfer intensity by 3.6 % and 4.7 % compared to rod-like and near-spherical nanoparticles, respectively. Compared with deionised water, the maximum temperature difference in the flow channel of the nanofluid containing sheet-like nanoparticles was found to be reduced by 61.5 % when circulating up to 240 s. It indicates that the nanofluid formulation effectively improves the problem of uneven local heat transfer intensity between fluid and high-temperature granite. Finally, this study also calculated the net energy gain of the nanofluids by integrating the heat transfer rate and pumping power. Specifically, for the nanofluid containing sheet-like nanoparticles, the increased heat transfer rate is 16 times the increased pumping power under laminar flow conditions, and nearly 8 times that under turbulent flow conditions. This provides significant reference value for promoting the application of nanofluids in practical geothermal energy extraction.
研究领域:
地热能
·
传热学
·
纳米流体工程
·
能源系统
·
实验流体力学
✓ 已验证
产品关联
DOI
高影响因子
Geoenergy Science and Engineering
·
2025
·
IF 4.6
Ou Jiang,Xiuhua Zheng,Pei Wu,Luyao Ma,Xu Liu,Pengfei Jin,Pengxiang Zhang,Yang Yang,Haoyu Yu
Acidizing improves reservoir productivity, and foam acid fluid systems achieve both effective acidizing and reservoir protection compared to conventionally utilized acid fluids. Nevertheless, the current application of foam acid fluids is restricted to oil-gas reservoir stimulation, owing to the differences in development conditions between oil-gas and geothermal reservoirs. The transformative application of foam acid fluids from oil-gas to geothermal reservoirs can address the problems induced by conventional acid fluids in geothermal reservoirs, such as limited effective acidizing distance and difficulties in flowing back residual fluids. Here, a foam acid fluid system with typical foaming agents, including sodium dodecyl sulfate (SDS), cocoamidopropyl betaine (CAPB), dodecyl trimethyl ammonium bromide (DTAB) and decaethylene glycol monododecyl ether (DGME), with various foam stabilizer xanthan (XC) contents (0.3%−1.2%) is proposed. Its feasibility in low-temperature (25°C−90°C) geothermal reservoir stimulation is verified through foam stability and acidizing effects, containing dissolution and corrosion inhibition performances. The results shows that the foam acid fluids with DTAB and DGME at 1.2% XC have a required foam stability. A network micro-structure of foam stabilizers, the stronger intermolecular forces in the foaming system, and the chemical reaction stability of foaming agents, mutually contribute to the foam stability. Compared to non-foam acid fluids, foam acid fluids significantly retards acid-rock reaction, with a more uniform dissolution of the cuttings microscopically. The existence of bromide ion (Br – ) in DTAB enhances the corrosion of N80 steel, which is above an accepted corrosion speed. This study highlights the great application potential of foam acid fluid system in an efficient stimulation of low-temperature dolomite geothermal reservoirs.
研究领域:
地热能
·
石油工程
·
储层改造
·
胶体与界面科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）