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02. Fen Fakültesi / Faculty of Science

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Browsing 02. Fen Fakültesi / Faculty of Science by Department "İzmir Institute of Technology. Civil Engineering"

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    Citation - WoS: 2
    Citation - Scopus: 5
    Experimental Modeling of Antimony Sulfides-Rich Geothermal Deposits and Their Solubility in the Presence of Polymeric Antiscalants
    (Elsevier, 2022-05) Karaburun, Emre; Sözen, Yiğit; Sözen, Yiğit; Baba, Alper; Çiftçi, Celal; Şahin, Hasan; Şahin, Hasan; Demir, Mustafa Muammer; Baba, Alper; Akbey, Ümit; Yeşilnacar, Mehmet İrfan; Erdim, Eray; Regenspurg, Simona; Demir, Mustafa Muammer; 01. Izmir Institute of Technology; 04.04. Department of Photonics; 03.03. Department of Civil Engineering; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 04. Faculty of Science
    Antimony (Sb)-rich geothermal deposits have been observed in many geothermal power plants worldwide. They occur as red-colored, sulfidic precipitates disturbing energy-harvesting by clogging the geothermal installations. In order to prevent the formation of this scale, information on its physicochemical features is needed. For this purpose, Sb-rich sulfide-based deposits were synthesized at controlled conditions in a pressurized glass reactor at geothermal conditions (135 °C and 3.5 bar). Various polymeric antiscalants with different functional groups, such as acrylic acid, sulphonic acid, and phosphonic acid groups were tested for their effect on Sb sulfide solubility. An additional computational study was performed to determine the binding energy of Sb and S atoms to these groups. The results suggest that sulfonic acid groups are the most affective. Therefore, it was concluded that these macromolecule containing sulfonic acid groups and poly (vinyl sulfonic acid) derivatives could potentially act as antiscalants for the formation of antimony sulfide.
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    Article
    Citation - WoS: 20
    Citation - Scopus: 26
    Increasing Solubility of Metal Silicates by Mixed Polymeric Antiscalants
    (Elsevier Ltd., 2019-01) Topçu, Gökhan; Demir, Mustafa Muammer; Çelik, Aslı; Çelik, Aslı; Kandemir, Ali; Baba, Alper; Baba, Alper; Şahin, Hasan; Şahin, Hasan; Demir, Mustafa Muammer; 03.09. Department of Materials Science and Engineering; 04.04. Department of Photonics; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
    The 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.
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    Article
    Citation - WoS: 33
    Citation - Scopus: 43
    Types of the Scaling in Hyper Saline Geothermal System in Northwest Turkey
    (Elsevier Ltd., 2014-04) Demir, Mustafa Muammer; Demir, Mustafa Muammer; Baba, Alper; Baba, Alper; Atilla, Vedat; İnanlı, Mustafa; 03.03. Department of Civil Engineering; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Tuzla is an active geothermal area located in northwestern Turkey, 80km south of the city of Canakkale and 5km from the Aegean Coast. The geothermal brine from this area, which is dominated by NaCl, has a typical temperature of 173°C. Rapid withdrawal of fluid to ambient surface conditions during sampling causes precipitation of various compounds known as scaling. Scaling is one of the important problems in Tuzla geothermal system that reduces the efficiency of the geothermal power plant and causes economical loss. The aim of this study was to determine the type of scaling as a first step towards preventing its formation. The scales formed in the geothermal system were divided into two groups according to location: the ones that formed in downhole and the ones that accumulated along the surface pipeline. Both scales were examined in terms of their elemental composition, structure and morphology using XRF, XRD, and SEM, respectively. The former was found to be mainly composed of PbS (Galena) and CaCO3 (aragonite or calcite). In contrast, the latter was heterogeneous in nature and consisted of mainly saponite like amorphous structure along with submicrometer-sized amorphous silica particles, layered double magnesium and iron hydroxide, and NaCl.