Kinetics of silica polymerization at various conditions için kapak resmi
Kinetics of silica polymerization at various conditions
Başlık:
Kinetics of silica polymerization at various conditions
Yazar:
Hasköylü Toker, Öykü Çağ, author.
Fiziksel Tanımlama:
viii, 49 leaves: charts;+ 1 computer laser optical disc.
Özet:
Silica is the most abundant element on Earth because the Earth's crust is composed mainly of metal silicates. The source of this silica is mainly volcanic rocks, which come to the surface through tectonic activity and are the primary source of heat for geothermal activity. The silica concentration in a geothermal fluid is higher than the solubility limit of natural waters, so scaling of (metal) silicates is often observed in geothermal operations. This situation has become critical for geothermal power plants. Since silicates have an insulating structure, they lead to a reduction in energy efficiency during fluid transport. The formation of silica-rich deposits should be investigated to minimize the negative effects of the scaling. Briefly, silicic acid molecules in the reservoir system are condensed, and the monomeric silicic acid molecules bind to each other via covalent bonds. In the course of this reaction, dimers, tetramers and short oligomers are formed, and eventually a large polymeric silica network is formed. In the presence of metals, both the kinetics of polymerization and the structure of the network are inevitably affected. In this study, the presence of kinetic parameters (different salts such as FeCl3, MgCl2, AlCl3 and NaCl), the reaction process, the rate, and the activation energy of silica polymerization at different temperatures between 25 and 90 °C were examined. The yellow silicomolybdate method was used to determine the concentration of monomeric silica. pH was found a stronger effect on the kinetics of silica polymerization than temperature. The neutral solution decreases rapidly, while the acidic solution has an induction phase in the first hour of polymerization. The order of the polymerization reaction was found as 3. The polymerization occurs in the initial phase, in the first 40 min, where the activation energy was found 29.52 ± 2.28 kJ/mol using Arrhenius equation and the rate constant was on the order of 4×10-8 mol-2-2 ∙L 2 ∙s -1
Konu Başlığı:
Tek Biçim Eser Adı:
Thesis (Master)--İzmir Institute of Technology:Environmental Engineering.

İzmir Institute of Technology: Environmental Engineering--Thesis (Master)
Elektronik Erişim:
Access to Electronic Versiyon.
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