Geothermics最新文献

{"title":"Ground source heat pump systems in Central Asia: A case study from Dushanbe, Tajikistan","authors":"Saeid Mohammadzadeh Bina ,&nbsp;Hikari Fujii ,&nbsp;Dursulton Qaisova ,&nbsp;Richard Lein ,&nbsp;Jamshed Rahmatov ,&nbsp;Fumiaki Inagaki","doi":"10.1016/j.geothermics.2025.103281","DOIUrl":"10.1016/j.geothermics.2025.103281","url":null,"abstract":"<div><div>This study evaluated the applicability of a ground source heat pump GSHP system for heating and cooling applications in Dushanbe City, Tajikistan, by modeling an existing project in the city for the first time. Given the region's limited energy resources and heavy reliance on hydropower, the GSHP system presents a promising solution for sustainable heating and cooling demands in a country with a heating-dominated climate. The research employs numerical simulations validated with actual recorded data in the field, and providing a comprehensive analysis of both short-term and long-term performance calculating the heating and cooling Coefficient of Performance (COP) in the winter and summer, respectively. The model developed in FEFLOW software was validated perfectly using the TRT data including outlet temperature of the GHE and as well as ground temperature profiles recorded by an optical fiber sensor inserted into the GHE's return pipe from the beginning of the test until 48 h after test completion. The long-term simulation showed that the minimum ground temperature was only decrease about 1.3 °C during the 10-years of operation with the COP decrement of about 0.28, which was fairly acceptable performance. Results highlight the potential of GSHP systems to enhance energy efficiency and reliability in this country and as well as Central Asia. This pioneering study demonstrates the viability of GSHP technology in Tajikistan, offering valuable insights for future energy planning and sustainable development in the region.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"128 ","pages":"Article 103281"},"PeriodicalIF":3.5,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geothermal resources in the northern Harrat Rahat volcanic field, Saudi Arabia: A drilling and field data assessment","authors":"Alan Bischoff ,&nbsp;Khalid A. Bankher ,&nbsp;Ehab A. Alashi ,&nbsp;Teppo Arola ,&nbsp;Haitham S. Brinji ,&nbsp;Károly Németh ,&nbsp;Annu Martinkauppi ,&nbsp;Akram H. Jabrte ,&nbsp;Evgenii Kortunov ,&nbsp;Ibrahim S. Alzahrani ,&nbsp;Ilkka Martinkauppi ,&nbsp;Rami A. Melibari","doi":"10.1016/j.geothermics.2025.103272","DOIUrl":"10.1016/j.geothermics.2025.103272","url":null,"abstract":"<div><div>Geothermal energy exploration is gaining momentum in the Kingdom of Saudi Arabia. Here, we present the findings of a geothermal exploration programme conducted in the northern Harrat Rahat volcanic field. Our investigations highlight the geological events, volcanological characteristics, and structural patterns that influence the formation and distribution of geothermal resources in the area. The main objective was to identify conventional geothermal systems suitable for commercial electricity generation and secondarily estimate the potential of unconventional geothermal systems. Key findings include the recording of a modest conduction-dominated geothermal gradient of up to 23.6 °C/km. Although no active geothermal reservoirs were found (maximum measured temperature of 54 °C), the mineral paragenesis, including chlorite, epidote, and rhodonite associated with hydraulic brecciation, indicates that fossil high-temperature (∼300 °C) hydrothermal systems were once working at shallow depths (&lt;1000 m) beneath the Rahat. Accounting the uncertainties of our preliminary study, we estimate that unconventional geothermal systems could potentially achieve MWe-scale capacities if built at depths of nearly 6 km. The results of our research provide valuable insights into the geothermal potential of the Rahat volcanic field and contribute to expanding the understanding of geothermal resources in Saudi Arabia and similar geological settings worldwide.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"128 ","pages":"Article 103272"},"PeriodicalIF":3.5,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrochemical zonation and geochemical processes of geothermal water in Beijing","authors":"Lijuan Yuan ,&nbsp;Pengfei Shen ,&nbsp;Jinping Zhang ,&nbsp;Junwei Yang ,&nbsp;Xiangjun Kong","doi":"10.1016/j.geothermics.2025.103273","DOIUrl":"10.1016/j.geothermics.2025.103273","url":null,"abstract":"<div><div>Geothermal resource constitutes a vital clean energy in Beijing, playing a pivotal role in advancing the city's 'dual carbon' target. However, the hindrance to the widespread utilization of geothermal resources in Beijing lies in the idleness of over 400 geothermal wells, primarily due to an insufficient understanding of geothermal geological conditions. To address this, we integrated geochemical data from 149 geothermal wells across the city with geological and seismic data, and explored the processes and controlling factors influencing the hydrochemical zonation within the karst thermal reservoir. Our findings are as follows: 1) The geothermal water exhibits distinct zonation in terms of water types and ion content, with high SO₄^2- levels (≥100 mg/L, up to 1420 mg/L), high F^- levels (≥7 mg/L, up to 30 mg/L), and high Cl^- levels (≥300 mg/L, peaking at 3444 mg/L) distributed in strips, areas, and spots, respectively. 2) The dissolution of sulfate-bearing rocks and fluorite is a crucial factor controlling the high concentrations of SO₄^2- and F^- in geothermal water. The NY-TX fault, which serves as the boundary of the geothermal field, and the active fault indentified through seismic activities within the geothermal field, are significant factors influencing the zonation. 3) Geothermal water in Beijing is a mixture of atmospheric precipitation and formation water. From a planar perspective, three subsystems of geothermal water circulation can be identified in the kasrt reservoir. GF8-2 can be regarded as an independent geothermal water system, characterized by Cl^- and TDS concentrations that reach 3444 mg/L and 6286.7 mg/L, respectively, suggesting minimal influence from atmospheric precipitation. This insight has significant implications for guiding the large-scale utilization and management of geothermal resources in the capital city.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"128 ","pages":"Article 103273"},"PeriodicalIF":3.5,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Repurposing of hydrocarbon wells for Enhanced Geothermal System (EGS) development","authors":"Lingkan Finna Christi ,&nbsp;Ingo Sass ,&nbsp;Ben Norden ,&nbsp;Guido Blöcher ,&nbsp;Günter Zimmermann ,&nbsp;Hannes Hofmann","doi":"10.1016/j.geothermics.2025.103268","DOIUrl":"10.1016/j.geothermics.2025.103268","url":null,"abstract":"<div><div>The Groß Schönebeck research platform represents a case study for the reuse of the abandoned hydrocarbon well E GrSk 3/90. A detailed description of well selection criteria, subsurface conditions, and well modification procedures is presented as a workflow for the repurposing of hydrocarbon well as an injection well for an EGS development. The procedure is complemented by a sequence of hydraulic stimulations leading to the development of the site as an EGS doublet well system. In this study, numerical simulations were carried out using the CMG STARS software to validate the numerical model of the existing matrix-dominated EGS against the hydraulic tests carried out in the field between 2011 and 2013. A sensitivity analysis was performed and it shows that matrix permeability is the most influential parameter followed by fracture permeability. The calibrated model and the result of the sensitivity analysis were then used as the basis for a predictive model of a fracture-dominated EGS concept. The new concept is presented with the technical feasibility of repurposing Gt GrSk 4/05 (A2) well as an injection well, E GrSk 3/90 well as a seismic monitoring well, and a design layout for the new production wells. This concept, comprising 16 fractures with a parallel horizontal well configuration, exhibits a 16-fold increase in the Productivity Index (PI) and Injectivity Index (II) at a production rate of 60 m³ <!-->h⁻¹compared to the previous matrix-dominated EGS development concept. A production rate of 180 m³ <!-->h⁻¹is achievable with a maximum production life of 30 years with two production wells.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"128 ","pages":"Article 103268"},"PeriodicalIF":3.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mixing mechanisms control the hydrogeochemical composition in medium-low enthalpy geothermal areas","authors":"Yunfei Bai ,&nbsp;Zheming Shi ,&nbsp;Jue Tong ,&nbsp;Hailong Ye ,&nbsp;Xiaocheng Zhou ,&nbsp;Guangcai Wang ,&nbsp;Kai Liu ,&nbsp;Shouchuan Zhang","doi":"10.1016/j.geothermics.2025.103270","DOIUrl":"10.1016/j.geothermics.2025.103270","url":null,"abstract":"<div><div>China has abundant medium-low enthalpy geothermal resources, primarily distributed across sedimentary basins, coastal regions, and mountainous fault zones. The Wugongshan area is a typical medium-low enthalpy geothermal field that has attracted considerable attention recently due to its widespread geothermal resources. Previous studies have investigated the hydrochemical evolution and formation mechanisms of hydrothermal systems in the Wugongshan area, and significant mixing processes have been found. However, the effects of these mixing processes on the geothermal reservoir temperature and the hydrochemical evolution in the area have not yet been investigated in detail, which has limited understanding of the hydrothermal system in this area. The integrated multicomponent geothermometry (IMG) method was employed in the present study to estimate the reservoir temperatures, effectively mitigating inaccuracies caused by mixing processes. The results showed that the geothermal fluid in the Wugongshan area comprised 26–82 % initial geothermal fluid and 18–74 % cold water. Ancient meteoric water was the principal source of geothermal fluids, and the isotopic signatures of geothermal fluids and shallow cold water became increasingly similar as more shallow cold water was mixed in. Additionally, the influx of shallow cold water, which carried CO₂ and O₂ from the soil, enhanced the weathering of silicate minerals and the oxidation of sulfide minerals in the research area, altering the concentrations of HCO₃^–, SO₄^2– and trace element concentrations in the geothermal fluid. The results also revealed that the fault zones play a crucial role in facilitating the circulation and upward migration of deep geothermal fluids, and the mixing processes are a key mechanism driving geochemical changes in the geothermal waters.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"128 ","pages":"Article 103270"},"PeriodicalIF":3.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogen emission characteristics of Changbaishan Volcano: Spatial and temporal distribution and genesis","authors":"Guohui Gu ,&nbsp;Le Hu ,&nbsp;Xiaodong Pan ,&nbsp;Ying Li ,&nbsp;Zhaofei Liu ,&nbsp;Fengxia Sun ,&nbsp;Guangpei Zhong","doi":"10.1016/j.geothermics.2025.103269","DOIUrl":"10.1016/j.geothermics.2025.103269","url":null,"abstract":"<div><div>Active volcanoes provide conduits for deep gas migration and are potential targets for hydrogen (H₂) resources. Changbaishan Volcano is one of the largest and most potentially hazardous active volcanoes in Asia, with strong volcanic gas emissions, but systematic studies on the characteristics of H₂ emissions are lacking. The source and controlling factors of H₂ in Changbaishan Volcano, as well as the relationship between H₂ and magmatism, are still unclear. In this work, we analysed the characteristics of H₂ emissions from hot springs, geothermal wells, and the soils of Changbaishan Volcano. In addition, we examined the genesis of H₂ by combining He isotopes and water–rock interaction experiments. The results show that the average concentration of H₂ in the hot springs is 9.5 ppm. Isotopic characterization revealed that the Changbaishan volcanic gases were emitted from the mantle and mixed with small amounts of crustal material. However, during the 2002–2005 volcanic unrest, the H₂ concentration increased abruptly to 321.5 ppm, and the corresponding isotopic characterization was converted to a single magmatic genesis. These findings indicate that the hot spring H₂ originated mainly from the magma chamber and was controlled by deep magmatism. The measurement results of H₂ concentrations reveal that &gt;24 % of the surveyed area has values exceed the background threshold. The average H₂ concentration in the anomaly area reached 45.51 ppm, much higher than that in the hot springs and geothermal well during the volcanic quiescent period, suggesting that the soil gas was unlikely to be originated from magmatic degassing alone. Considering the widely-distributed basalts in Changbaishan Volcano, combined with the results of water–rock interaction experiments, we believe that alteration of basaltic rocks probably provides the main source for the H₂ in the soil. Global comparative analyses indicate that lithology is an important factor for soil H₂ emissions in volcanic areas. Volcanoes with higher soil H₂ emissions are predominantly composed of mafic volcanic rocks.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"127 ","pages":"Article 103269"},"PeriodicalIF":3.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143328852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Applications and implications of monitoring surface hydrothermal deposits at Lastarria Volcano, Chile, using multispectral satellite data and cloud computing","authors":"Guosheng Gao ,&nbsp;Thomas R. Walter ,&nbsp;Daniel Müller ,&nbsp;Pouria Marzban ,&nbsp;Simon Plank","doi":"10.1016/j.geothermics.2025.103255","DOIUrl":"10.1016/j.geothermics.2025.103255","url":null,"abstract":"<div><div>Studies of hydrothermal alteration involve the effects of circulating hot and aggressive fluids in volcanic environments, which are crucial for understanding volcanic hazards, slope instability, and steam-driven explosions. Visible hydrothermal deposits at the surface provide direct evidence of subsurface hydrothermal systems or volcanic unrest and can be detected by remote sensing tools. Here, we introduce the Hydrothermal Deposit Index (HDI), a remote sensing-based index derived from the Ultra Blue, Red, SWIR 1, and SWIR 2 bands of multispectral satellite data that allows spatiotemporal analysis of surface hydrothermal deposits. We apply the HDI approach to Lastarria, a stratovolcano on the border between Chile and Argentina that shows vigorous fumarole activity. With the support of Google Earth Engine (GEE), we mitigate environmental interferences like steam plumes and snow, thereby guaranteeing the precision of findings. Our HDI results identify three main depositional zones on the Lastarria Volcano, covering approximately 600,000 m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>, and are validated against independent field surveys. Time series analysis reveals three distinct patterns of HDI variation and dynamic shifts in hydrothermal activity within the summit crater and flank regions. Furthermore, we demonstrate that activity at the summit and flanks occurs in succession and that an increase in HDI concurs with the appearance of new sulphur flows. This research contributes to the advancement of remote sensing methodologies for volcano monitoring and emphasizes the importance of spatiotemporal dynamics in hazard assessment.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"127 ","pages":"Article 103255"},"PeriodicalIF":3.5,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143149056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of geothermal resources for power generation on La Palma Island, Canary Islands","authors":"Daniel Fariña-González,&nbsp;Óscar García-Afonso,&nbsp;Agustín M. Delgado-Torres","doi":"10.1016/j.geothermics.2025.103263","DOIUrl":"10.1016/j.geothermics.2025.103263","url":null,"abstract":"<div><div>Canary Islands archipelago is the sole region in Spain with a recognized potential of geothermal resources suitable for power generation. Supported by geological and geothermal evidences, the interest of integrating the geothermal power in some islands has risen due to the excellent prospect that this resource offers to isolated and high fossil fuel dependent power systems (renewable nature, lower cost, dispatchability). In this paper, the results of the first probabilistic assessment of the geothermal power potential of La Palma island are presented. Starting from the information obtained in previous geophysical and geochemical studies two specific zones, named as L1 and L2, are selected for further analysis. The stochastic Monte Carlo simulation approach is applied in combination with the well-known geothermal resource assessment volumetric method. Intervals for the most relevant reservoir characteristics are derived from gravimetric, magnetoteluric and ambient seismic noise tomography techniques, whereas other parameter values are estimated based on the current general literature or adopted from reference projects.</div><div>The obtained results show power capacity potentials of 10.9 MWe and 6.7 MWe for L1 and L2 zones respectively at a 90% confidence level. With this capacity in place, the contribution of renewable electricity would rise up to 45.2% or 31.0% if only the L1 or L2 potential would be exploited respectively. In addition, other benefit indicators such as land use, CO² emission abatement or the generation cost have been quantified. Finally, to enhance the relevance of the results, a sensitivity analysis of the Monte Carlo outputs was performed as a function of the most likely reservoir volume and recovery factor values. In this case, power potential ranges of 8.3 - 13.4 MWe and 5.2 - 8.3 MWe for zones L1 and L2 respectively are found.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"127 ","pages":"Article 103263"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143149014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental analysis of primary factors controlling carbonate rock dissolution capability and its impact on geothermal reservoir modification","authors":"Yuxiu Li ,&nbsp;Yunying Huang ,&nbsp;Yuanfu Zhang ,&nbsp;Deze Liang ,&nbsp;Jianlong Zhao ,&nbsp;Xiaohan Zhang ,&nbsp;Kai Ma ,&nbsp;Yuchuan Yi ,&nbsp;Hanqi Wang ,&nbsp;Jianying Guo","doi":"10.1016/j.geothermics.2024.103124","DOIUrl":"10.1016/j.geothermics.2024.103124","url":null,"abstract":"<div><div>Carbonate geothermal reservoir is one of the main thermal reservoirs for geothermal resources development and utilization, with abundant thermal resources and good exploitation conditions. The dissolution of carbonate rocks is an important factor in the formation of geothermal reservoirs. In order to explore the control effect of lithology, temperature, and pressure on the dissolution of carbonate rocks, dolomite, limestone, marlstone, and dolomite limestone were used as rock samples. A 0.2 % acetic acid solution was employed for the simulation. A high-temperature and high-pressure solution simulation device was utilized to simulate the dissolution process from surface to deep burial conditions. The results show that: The amount of limestone dissolution follows a “V-shaped” pattern in response to temperature changes and exhibits an “up-down cycle” in response to pressure variations. Furthermore, the impact of temperature on dissolution is significantly greater than that of pressure.The karst erosion and burial depth of different lithologies exhibit a trend of \"initial increase followed by decrease,\" existing a \"peak of dissolution\". The dissolution peak of dolomite occurs at approximately 4500 m, while that of limestone exceeds 6500 m. The dissolution capacity of mudstone is relatively low, reaching its maximum around 4000 m. Consequently, three potential stages for the formation of high-quality heat storage can be delineated as shallow to moderately buried limestone, moderately to deeply buried dolomite limestone, and deeply buried dolomite.Simultaneously, the “selective” mechanism of dissolution of carbonate rocks is examined, encompassing both the “composition selective” dissolution of calcite during the dissolution process and the “structure selective” dissolution occurring within fissures, particle edges, and crystal surfaces.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"126 ","pages":"Article 103124"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Ethylenediaminetetraacetate (EDTA) on the polymerization and adsorption of silicic acid in the presence of iron: Implication to the prevention of silica scale formation from acidic geothermal water","authors":"Saefudin Juhri ,&nbsp;Kotaro Yonezu ,&nbsp;Takushi Yokoyama","doi":"10.1016/j.geothermics.2025.103267","DOIUrl":"10.1016/j.geothermics.2025.103267","url":null,"abstract":"<div><div>As conventional geothermal energy resources are increasingly explored and exploited, there is a need to explore non-conventional geothermal energy resources for future development of geothermal energy, such as using acidic geothermal water. However, studies have shown that simple neutralization of the acidic water might bring a risk of silica scaling due to the metal contents, such as iron (Fe). Therefore, in this study, the chelating effect of ethylenediaminetetraacetate (EDTA) on Fe was examined to prevent the polymerization of silicic acid, its precipitation, and its adsorption on the surface of silica gel. Results of laboratory experiments showed that adding Fe(III) accelerated the polymerization of silicic acid when NaOH was used to adjust the pH of acidic geothermal water. On the contrary, the acceleration effect of Fe(III) was not observed when EDTA·4Na was used to adjust the pH. The concentration of monomeric Fe(III) immediately decreased to almost 0 after adding EDTA·4Na, suggesting effective Fe(III) trapping by EDTA. The results of onsite adsorption experiments agreed with the laboratory experiment, where Fe(III) accelerated silicic acid's adsorption rate on the silica gel's surface, and EDTA effectively prevented its acceleration effect. The consistent result of the onsite experiment suggests the applicability of this method to prevent the precipitation of siliceous deposits and the formation of silica scale from Fe-bearing geothermal water.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"127 ","pages":"Article 103267"},"PeriodicalIF":3.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143149013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}