WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 16Citation - Scopus: 17Experimental Study and Kinetic Modeling of High Temperature and Pressure Co2 Mineralization(Elsevier Sci Ltd, 2024) Berndsen, Maximilian; Erol, Selcuk; Akin, Taylan; Akin, Serhat; Nardini, Isabella; Immenhauser, Adrian; Nehler, MathiasThe potential for in-situ CO2 sequestration was analyzed experimentally for one basaltic hyaloclastite sample from the Nesjavellir geothermal reservoir in Iceland and three metasedimentary rock samples from the K & imath;z & imath;ldere geothermal field in Turkey. Based on batch reaction experiments, this paper demonstrates the interaction between a CO2 gas-charged fluid and rock samples from these reservoirs. The experiments were conducted at 260 degrees C and 0.8 MPa, and 105 degrees C and 17 MPa for the basaltic and metasedimentary rocks, respectively. The experimental results indicate that CO2 sequestration within the glassy basaltic rocks is hampered by zeolite, chlorite, and anhydrite, which compete with carbonate minerals to uptake divalent cations at the P-T conditions applied. In contrast, the carbonation process for the metasedimentary rocks is inhibited by their mineralogical composition. Generally, these rocks are less reactive and provide an insufficient supply of divalent cations. The batch reactor experiments were numerically simulated with the PHREEQC geochemical modeling program. The simulations indicate that CO2 sequestration is feasible at the tested P-T conditions, provided that silicate and SO4 mineralization is suppressed for the basaltic rocks and that there is an effective source of divalent cations for the metasedimentary rocks.Article Citation - WoS: 7Citation - Scopus: 8Update for Reactive Transport Modeling of the Kızıldere Geothermal Field To Reduce Uncertainties in the Early Inspections(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2023) Erol, Selçuk; Akın, Taylan; Akın, SerhatThe development of carbon capture and storage techniques has become essential to reduce and mitigating CO2 emissions to the atmosphere. CarbFix1 and CarbFix2 projects carried out in Iceland demonstrated that the emissions of waste CO2 gas from geothermal power plants can be captured and mixed with the effluent geofluid and subsequently injected back into the geothermal reservoir. This experience gained in the CarbFix projects expanded into other geothermal fields around Europe, and one of the demonstration sites is the geothermal field in Turkey, Kızıldere. This paper focuses on the results of an updated study on early field evaluations with reactive transport simulations. In the new three-dimensional numerical model, the geological formations and fault zones were updated according to the well-logs data. Based on the tracer tests performed in the field, the anisotropic permeabilities between the wells were evaluated and imposed into the model. Geofluid chemistry, mineral components, and the volume fractions used as input in the simulations are modified depending on the performed laboratory experiments on the metamorphic schists taken from the geothermal site (i.e. X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning-electron microscope (SEM), and batch reactor tests). Different thermodynamic databases such as Lawrance Livermore National Laboratory (LLNL) and Thermoddem databases were tested using PHREEQC and TOUGHREACT programs for consistency with experiments. The thermodynamic conditions and the geofluid-rock-CO2 interactions prevent the mineralization of CO2 in the reservoir. This outcome differs from CarbFix projects in terms of the carbonization process, but the CO2 injection is still reliable with solubility-trapping in a geothermal reservoir to partially mitigate the emission. Roughly, 200 kt of CO2 in 10 years can be safely injected into the geothermal reservoir. According to the new analysis, the ratio of magnesium, sodium, and potassium varies in solid solution series of feldspars and clay minerals as albite end-member and montmorillonite/illite end-members, respectively. The evaluations of solid solution reactions are relatively limited in the law of mass action approach used by PHREEQC and TOUGHREACT. © TÜBİTAK.Article Citation - WoS: 27Citation - Scopus: 34Use of Abandoned Oil Wells in Geothermal Systems in Turkey(Springer, 2020) Kaplanoğlu, Murat A.; Baba, Alper; Gökçen Akkurt, GüldenHuman beings have been benefiting from geothermal energy for different uses since the dawn of civilization in many parts of the world. One of the earliest uses of geothermal energy was for heating and it was used extensively by Romans in Turkey. The Aegean region is favored with a large number of thermal springs known since ancient times. However, it was in the twentieth century that geothermal energy was first used on a large scale for direct use applications and electricity generation. The country's installed heat capacity is 3322.3 MWt for direct use and 1347 MWe for power production. Also, many drilled wells to extract oil or natural gas were abandoned for various reasons in the southeast of Turkey. Some of the oil fields have heat content that can be used for geothermal energy. Some even have hot fluid in the reservoir. This paper presents an investigation into how to use geothermal energy in abandoned oil and natural gas wells. Methods used to generate geothermal energy from abandoned oil fields other than conventional geothermal energy production are examined. Downhole heat exchangers can be used to extract heat without producing geothermal fluid which decrease gas emissions to the atmosphere and energy need for reinjection, from the abandoned oil wells to generate electricity or direct use applications. Using this method, it is possible to use abandoned wells in southeastern Turkey where this energy improves the economy of the region.Article Citation - WoS: 32Citation - Scopus: 30Geochemical and Hydrogeochemical Characteristics and Evolution of Kozaklı Geothermal Fluids, Central Anatolia, Turkey(Elsevier Ltd., 2019) Baba, Alper; Şener, Mehmet FurkanKozaklı is one of the most important areas of Central Anatolia in terms of geothermal potential and it is characterized by thrust and normal faults. These faults, accommodating deep circulation of hydrothermal fluids of meteoric origin, are the primary controls of the geothermal systems in this region. Chemical and isotopic composition of the hot springs and geothermal fluids was monitored throughout 2017. The surface temperature of the fluid ranges from 24.9 to 96 °C. The cold spring waters are mostly of the Ca-Mg−HCO3 type in the study area. Major element chemistry of the water reveals that the deep geothermal fluids are mostly of the Na-Ca-Cl-SO4 type while the shallow geothermal well waters are Ca-Na−HCO3 waters. Silica geothermometers suggest that the reservoir temperature ranges from 103 to 173 °C. Based on the δ18O–δD relationship, water samples have a high-altitude meteoric origin. Stable isotopic data indicate that the geothermal fluids are formed by local recharge and deep circulation of meteoric waters. The Rare Earth Elements and Yttrium (REY) composition showed that Eu, Ce and Y anomalies are related both to inheritance from geological host materials and the fractionation of these elements during water-rock interactions.Article Citation - WoS: 21Citation - Scopus: 27Increasing Solubility of Metal Silicates by Mixed Polymeric Antiscalants(Elsevier Ltd., 2019) Topçu, Gökhan; Çelik, Aslı; Kandemir, Ali; Baba, Alper; Şahin, Hasan; Demir, Mustafa MuammerThe increase of silicate solubility is a big challenge for both hot and cold water because it reduces the deposition of metal silicates frequently observed in such systems and causes operational obstacles. The deposition of silicate coats the inner surface of the pipelines in an uncontrolled manner and reduces the harvesting of energy from brines. In this work, the solubility performance of two commercial water-soluble polymeric agents (poly(ethylene glycol) (PEG) and poly(vinyl alcohol) (PVA)) of various molecular weights employing dosage from 25 to 100 mg/L was examined. Along with dispersant-type antiscalant, poly(acrylamide) (PAM), poly(vinylsulfonic acid, sodium salt) (PVSA), and poly(vinylphosphonic acid) (PVPA) having chelating acidic groups were employed. Metal silicate deposits were obtained artificially in the lab-scale pressurized reactor. The experimental conditions employed were quite similar to a model power plant located in Çanakkale, Turkey. The concentration of dissolved silica was increased from 130 to 420 mg/L when 100 mg/L PEG 1500 and 25 mg/L PVSA were employed as a mixture. For the atomic-level understanding of the interaction of chelating groups with metal cations, DFT calculations were performed too.Article Citation - WoS: 83Citation - Scopus: 92Source of Arsenic Based on Geological and Hydrogeochemical Properties of Geothermal Systems in Western Turkey(Elsevier Ltd., 2012) Baba, Alper; Sözbilir, HasanTurkey is an area of complex geology with active tectonics and high geothermal potential. Especially, the western part of Turkey is a region of abundant geothermal activity. Faults accommodating the deep circulation of hydrothermal fluids of meteoric origin are the primary means by which of geothermal systems are controlled in this region. Many of the thermal activities are related to the improved dilation on the ~E-W-strikes of the graben faults. This situation serves as a suitable environment for the presence of high levels of arsenic in geothermal water resources. The highest concentrations of naturally occurring aqueous arsenic (As) are found in certain types of geothermal waters, generally those related to major graben faults. In this regard, high arsenic concentrations in geothermal resources have been detected in Western Turkey, including but not limited to Biga Peninsulla, Gediz Graben, Kucuk, and Buyuk Menderes Graben with values ranging from 1 to 1419ppb in geothermal fluids. The thermal waters have surface temperatures of up to 100°C and reservoir temperatures range from 150 to 248°C in the Menderes Graben, from 120 to 287°C in the Gediz Graben, and from 153 to 174°C in Biga Peninsula. Hydrogeochemically, the Menderes graben and Gediz Graben thermal waters are of the Na-HCO3, Ca-HCO3, and Na-SO4 types, whereas some geothermal fluids such as those of Tuzla and Kestanbol in the Biga Peninsula, Çeşme, and Urla are of the Na-Cl type.Article Citation - WoS: 28Citation - Scopus: 30Hydrogeochemical and Isotopic Composition of a Low-Temperature Geothermal Source in Northwest Turkey: Case Study of Kırkgeçit Geothermal Area(Springer Verlag, 2011) Şanlıyüksel, Deniz; Baba, AlperChemical and isotopic compositions of three hot springs and one cold spring in the Kirkgecit geothermal field, located 15 km southwest of Canakkale-Biga in the northwest of Turkey, were monitored five times during 2005 and 2007. The physico-chemical characteristics of the hot springs are average discharge 3–3.5 L/s, surface temperature 45–52 C, pH 8.9–9.3, and electrical conductivity (EC) 620–698 lS/cm. The cold spring has a temperature of 12–13 C, pH 7.5–8.3, and EC 653–675 lS/cm. The hot waters are Na-SO4 type, whereas the cold water is Ca-HCO3 type. Chemical geothermometers suggest that the reservoir temperature is around 80–100 C. The isotopic data (oxygen-18, deuterium and tritium) indicate that the thermal waters are formed by local recharge and deep circulation of meteoric waters.Article Citation - WoS: 66Citation - Scopus: 79Piping Network Design of Geothermal District Heating Systems: Case Study for a University Campus(Elsevier Ltd., 2010) Yıldırım, Nurdan; Toksoy, Macit; Gökçen, GüldenGeothermal district heating system design consists of two parts: heating system and piping network design. District heating system design and a case study for a university campus is given in Yildirim et al. [1] in detail. In this study, piping network design optimisation is evaluated based on heat centre location depending upon the cost and common design parameters of piping networks which are pipe materials, target pressure loss (TPL) per unit length of pipes and installation type. Then a case study for the same campus is presented. © 2010 Elsevier Ltd.Article Citation - WoS: 24Citation - Scopus: 25Identification of Extracellular Enzyme Producing Thermophilic Bacilli From Balcova (agamemnon) Geothermal Site by Its Rdna Rflp(John Wiley and Sons Inc., 2004) Yavuz, Elif; Güneş, Hatice; Harsa, Hayriye Şebnem; Yenidünya, Ali FazılAims: Molecular characterization of extracellular enzyme producing thermophilic bacilli from Balcova geothermal site. Methods and Results: Three types of geothermal samples were collected: mud, re-injection water, and samples from uncontrolled hydrothermal vents. Isolates grown at 55°C in culture media prepared in sterilized re-injection water, were screened for extracellular enzyme activity by using eight different substrates: casein, carboxymethyl-cellulose, pectin, polygalacturonic acid (PGA), soluble starch, Tween 20 and 80, and xylan. In total, 109 thermoaerophilic isolates were selected. All of the isolates could hydrolyse Tween 20 (100%) but not Tween 80. Soluble starch was hydrolysed by 96%, casein by 55%, xylan and carboxymethylcellulose by 9%, and pectin and PGA by 2% of the isolates. The isolates were grouped into 14 different homology groups by the restriction pattern analysis of 16S-internal transcribed spacer (ITS) rDNA RFLP. Each of the RFLP groups was also studied by 16S rRNA gene partial sequence analysis. Plasmid DNA profiles revealed that 15 of the isolated strains contained small plasmid DNA molecules ranging in size from 12 000 to 35 000 bp. Conclusions: Combined analysis of 16S-ITS rDNA RFLP and 16S rRNA gene partial sequence results indicated the presence of novel or existing species of Anoxybacillus (nine species) and Geobacillus (three species). Significance and Impact of the Study: In this study 16S-ITS rDNA RFLP was applied for the first time to differentiate thermophilic bacilli. It was also the first study on thermophilic bacilli of Balcova geothermal site.Article Testing Corrosion Rates on Steel Piping in Geothermal District Heating(National Association of Corrosion Engineers, 2008) İnce, Umut; Toksoy, Macit; Güden, MustafaThe corrosion behavior of St-37 pipeline carbon steel (CS) in a geothermal district heating system was tested at two different fluid velocities. An experimental set-up, directly connected the the end of the transmission line of a geothermal well, was used to assess the corrosion of St-37 steel tensile test coupons prepared in accordance with ASTM E8 in geothermal fluid. The geothermal fluid entered the set-up with a relatively low velocity, 0.02 m/s, and then injected into the well with a relatively high fluid velocity, 9.6 m/s. It was observed that while the uniform corrosion rates were relatively low, pitting corrosion rate, mainly driven by the sulfate-reducing bacteria (SRB) activity, was relatively high and more pronounced at low fluid velocities. St-37 steel material is prone to the pitting type corrosion, thus a biocide chemical addition and the fluid velocity of 2 to 3 m/s in transmission line were recommended to reduce SRB activity to reduce the pitting corrosion rate.