Browsing by Author "Tonkul, Serhat"

Now showing 1 - 4 of 4

Citation Count: 1
Characterization of Sb scaling and fluids in saline geothermal power plants: A case study for Germencik Region (Buyuk Menderes Graben, Turkey)
(Pergamon-elsevier Science Ltd, 2021) Tonkul, Serhat; Baba, Alper; Demir, Mustafa M.; Regenspurg, Simona; Demir, Mustafa
Turkey is located on the seismically active Alpine-Himalayan belt. Although tectonic activity causes seismicity in the Anatolian plate, it also constitutes an important geothermal energy resource. Today, geothermal energy production is heavily concentrated in Turkey's Western Anatolia region. Graben systems in this region are very suitable for geothermal resources. The Buyuk Menderes Graben (BMG) is an area of complex geology with active tectonics and high geothermal potential power. Germencik (Aydin) is located in the BMG, where the geothermal waters include mainly Na-Cl-HCO3 water types. This study examined the stibnite scaling formed in the preheater system of the Germencik Geothermal Field (GGF). The formation of the stibnite scaling on the preheater system dramatically reduces the energy harvesting of the GGF. Considering the stibnite scaling in the surface equipment, the optimum reinjection temperature was determined as 95 degrees C to prevent stibnite scaling in the GGF.
Citation Count: 5
Hydrogeology and hydrogeochemistry of the geothermal systems and its direct use application: Balcova-Narl?dere geothermal system, Izmir, Turkey
(Pergamon-elsevier Science Ltd, 2022) Baba, Alper; Sozbilir, Hasan; Sayik, Tolga; Arslan, Sinan; Uzelli, Taygun; Tonkul, Serhat; Demir, Mustafa M.; Demir, Mustafa
The Balcova-Narlidere geothermal system, located in western Turkey, is an extensional domain type geothermal play. Geological, hydrogeological, and geothermal studies have been done in the Balcova-Narlidere geothermal field since 1960. As a result of these studies, production and research wells were drilled in the area by both the public and private sectors. Of the 37 wells drilled in the Balcova-Narlidere geothermal field, 26 were drilled by Izmir Geothermal Energy Company Inc. (16 productions, 4 re-injection, 4 gradientst, 2 unused) and 11 by the Izmir Governorship Investment Monitoring and Coordination Department and companies in the private sectors. There are two reservoirs, one shallow and one deep, in the geothermal field. Well depths are less than 200 m in the shallow reservoir. The deep production wells have depths ranging from 400 to 1,100 m and reservoir temperatures reaching 140 degrees C. The electrical conductivity (EC) values in the shallow production wells range from 1,200 to 1,500 mu S/cm. EC values in the deep production wells vary from 1,871 to 2,025 mu S/cm, and all geothermal fluids in the field are mineral-rich waters. In the Izmir geothermal district heating system, the newest technologies are used, and operational costs are very low. Izmir Geothermal Energy Company Inc. has been operating since 1996 and has reached 38,460 residences. The current capacity of the system is approximately 160 MWt. Cooling systems continue to spread in Turkey, focusing on electric air conditioning systems and geothermal heating systems, but both economic and applicability problems have slowed the expansion of cooling systems. However, Izmir Geothermal Energy Company Inc. began operating its first geothermal cooling application in Balcova in 2018, cooling 1,900 m2 of the indoor area by lithium bromide absorption and 90/85 degrees C geothermal temperature regime by supplying 6/9 degrees C clean cold water to the coolers in the buildings. These results show that the extensional domain type geothermal system in the Balcova-Narlidere region is suitable for both heating and cooling applications.
Natural groundwater recharge in the Alaşehir sub-basin (Gediz basin, Turkey)
(Izmir Institute of Technology, 2018-12-22) Tonkul, Serhat; Baba, Alper; Şimşek, Celalettin
The increase in water utilization due to climate change in recent years, as well as excessively growing population causes to an increase in usage of groundwater and threatens water resources. Dams and artificial lakes are being constructed to ensure the sustainability of water resources, but there is much evaporation on large surface of these structures. Due to reason that the evaporation losses are not experienced, the groundwater recharge by direct rainfall becomes important. Groundwater recharge protects the water without too much evaporation in the basins and increases the potential of water resources and ensures sustainability. The aim of this study is to determine alluvial aquifer recharge in Alaşehir (Manisa) sub-basin using numerical and chemical methods. In addition to this aim, the mechanism of mixing of groundwater and geothermal fluid has also been examined. The Gediz Basin, located in the west of Turkey constitutes 2% of the country, has an important groundwater potential in the area where it is used. The Alasehir sub-basin, located in the southeast of the Gediz Basin and having extensive withdrawal for irrigation, constitutes the study area. Alluvial aquifer is the main groundwater bearing lithological unit in the plain. Twenty-five research wells, which is ranging from 20 m to 50 m in depth, were opened for the calculation of the recharge of the aquifer. Soil characterization was done on the core samples and the aquifer characterization was performed and the alluvial aquifer recharge was calculated. As a result, the recharge value of annual precipitation is range from 21.78 mm to 68.52 mm and average recharge from precipitation is 43.09 mm in the wells which are opened into the alluvium aquifer. According to the numerical model, this amount of recharge corresponds to 10% of the amount of annual rainfall. This estimated recharge ratio directly represents recharge from precipitation into the aquifer. According to the results of the chemical method, it is understood that the average recharge value from precipitation is 16.38%. In addition, the mixing ratio of the groundwater and geothermal fluid is 17% in the sub-basin. Keywords Aquifer Characterization, Alaşehir, Precipitation Recharge, Numerical Modelling
Citation Count: 2
Testing the Performance of Various Polymeric Antiscalants for Mitigation of Sb-Rich Precipitates Mimicking Stibnite-Based Geothermal Deposits
(Wiley-hindawi, 2020) Ciftci, Celal; Karaburun, Emre; Tonkul, Serhat; Baba, Alper; Demir, Mustafa M.; Yesilnacar, Mehmet Irfan; Demir, Mustafa
Scaling is frequently observed in geothermal fields and reduces the energy harvesting of power plants. Recently, Sb-rich deposits have developed in many fields around the world. Various polymeric macromolecules have been used as antiscalants to mitigate the formation of scale. Testing potential commercial antiscalants in field conditions is a tedious and costly process. The artificial synthesis of geothermal deposits in the lab is a more practical and economical way to test the performance of antiscalants. This study obtained a Sb-rich deposit by refluxing SbCl3 and Na2S center dot 3H(2)O in 18 h. The product was found to be a mixture of Sb2O3 and Sb2S3. We examined the performance of antiscalants such as poly(ethylene glycol), poly(vinyl pyrrolidone), Gelatin, and poly(vinyl alcohol) of various molecular weights at 5 to 100 ppm. The formation of Sb2S3 is suppressed in the presence of the polymeric antiscalants. The dosage was found to be critical for the solubilization of Sb-rich deposits. Gelatin of 5 ppm showed the highest performance under the conditions employed in this study. While low dosages improve the concentration of [Sb3+], high dosages are required to increase the solubility of [S2-]. Moreover, the amount of deposit is reduced by 12.4% compared to the reference (in the absence of any polymeric molecules). Thus, comparatively, Gelatin shows the most promising performance among the molecules employed.