Thermal Power Plants In Turkey Research Articles

Techno-Economic and Environmental Analysis of the Integration of Solar Tracked or Fixed-Tilt Photovoltaic Power Plants to Open Coal Fields of Thermal Power Plants in Turkey

Techno-Economic and Environmental Analysis of the Integration of Solar Tracked or Fixed-Tilt Photovoltaic Power Plants to Open Coal Fields of Thermal Power Plants in Turkey

Nonlinear static analysis of thermal power plant buildings

When steel structure is adopted in the main building of domestic thermal power plant, steel frame-center support structure is often adopted. The main building of a 2×660MW thermal power plant in Turkey is located in a high-intensity area, the earthquake area is Zone 1, and the building site category is Z2. In order to make the structure have better ductility and energy dissipation capacity under rare earthquakes, the structure adopts the form of steel frame-eccentric support structure. Through the nonlinear static analysis of the structure, the performance of the structure under the action of rare earthquakes is studied, which provides reference experience for future engineering design. The analysis results show that the energy dissipating beam has played a good role in dissipating energy under the action of rare earthquakes, effectively protecting the main structure, and the structure has not entered a collapsed state.

Process Development of Fly Ash-Based Geopolymer Mortars in View of the Mechanical Characteristics.

This study aimed to determine the effects of design parameters, including the liquid/solid ratio (L/S), Na2SiO3/NaOH weight ratio, and curing temperature, on class F fly ash-based geopolymer composites. For this purpose, two disparate sources of fly ash were supplied from Çatalağzı (FA) and İsken Sugözü (FB) Thermal Power Plants in Turkey. Two different L/S ratios of 0.2 and 0.4 were used. The Na2SiO3/NaOH ratios in the alkaline solutions were 1, 1.5, 2, 2.5, and 3 by weight for each type of geopolymer mixture. Then, 40 different mixes were cured at two specific temperatures (70 °C and 100 °C) for 24 h and then preserved at room temperature until testing. Thereafter, the physical water absorption properties, apparent porosity, and bulk density were examined at 28 days on the hardened mortars. Additionally, compressive and flexural tests were applied to the geopolymers at 7, 28, and 90 days. It was found that the highest compressive strength was 60.1 MPa for the geopolymer manufactured with an L/S of 0.2 and Na2SiO3/NaOH ratio of 2. Moreover, the best thermal curing temperature for obtaining optimal strength characteristics was 100 °C for the FB.

Ternary Diagrams for Predicting Strength of Soil Ameliorated with Different Types of Fly Ash

In recent years, the use of geopolymer materials for ground improvement has increased with the growth in the construction sector. The lignite coal used in the thermal power plants in Turkey has low-calorie content. Thus, fly ash from these thermal power plants has high-lime content, making it unsuitable for cement production or as a cement additive material. Therefore, it is necessary to find different areas where fly ash can be utilised. In this study, the fly ashes of six power plants were tested to improve the properties of cohesive soil. The effects of fly ash along with the soil properties on improving the physicomechanical properties of the soil were examined with different mix designs. The effects of the curing period on the soil strength values were examined, and the unconfined compressive strength values of all mixtures were compared with those of the controlled specimens prepared with optimum water content. In the literature, seventeen various case studies on fly ash–soil remediation have been investigated. The data of this study and other studies were evaluated together, and multiple regression and artificial neural network analyses were performed to estimate the improved soil strength. Additionally, ternary contour diagrams were designed for assessing the fly ash–mixed soil strength using the physical and mechanical properties of the soil and fly ash.

Ecological assessment of heavy metals in soil around a coal-fired thermal power plant in Turkey

In this study, heavy metal concentrations in agricultural surface soil (0–5 cm) samples collected from the area around the Kangal lignite-fired thermal power plant were determined using energy-dispersive X-ray fluorescence spectrometry. Also, the pH values of agricultural soil samples were measured to assess the level of acidification. Geo-accumulation index (Igeo), enrichment factor (EF), contamination factor (CF), contamination degree (CD), modified contamination degree (mCD), and pollution load index (IPL) were estimated to assess the heavy metals pollution in soil samples. The average concentration of Fe, Ti, Mn, Cr, Ni, Zn, Zr, Co, Cu, Pb, As, Sn and Hg was found as 39,065 ± 5096, 2262 ± 738, 721 ± 119, 713 ± 236, 610 ± 199, 82 ± 37, 65 ± 26, 64 ± 19, 29 ± 3, 17 ± 7, 9 ± 7, 3 ± 1 and 2 ± 1 mg kg−1, respectively. The values of pH varied from 7.5 to 8.2 with an average value of 8.0 (moderately alkaline). The Igeo, EF and CF results reveal that the study area is heavily or very highly contaminated with Cr, Ni, and Hg. On the basis of the IPL value, the soil samples are polluted with heavy metals. However, the mCD indicates moderate heavy-metal contamination of the soil samples.

Efficiency change of coal used for energy production in Turkey

A large part of the coal produced is consumed in thermal power plants in Turkey. Therefore, the energy policies focusing coal in the center is important for Turkey. Considering the lignite reserves of Turkey, as well as the effective use of these coal, a large part of the energy need will be met through local sources. Malmquist productivity index (MPI) has been utilized to analyse the effectiveness variation for the use of coal in Turkey, meeting an enourmous amount of its energy essentials through imports, in energy production between the years 2009–2018. As a result of the analyzes made; it has been determined that the efficiency change values of coal used in the production of electric energy increased by 16.4% due to the rise in the use of imported coal and asphaltite. In recent years, there has been no significant change in the use of lignite as it is determined that there is a 3.1% decrease in efficiency development due to the absence of new investments in hard coal -based electricity generation.

Application of exergoeconomic analysis for power plants

Currently, energy resources are rapidly consumed. Therefore, scientists and engi?neers study the effective use of energy. In the present study, a thermodynamic and exergoeconomic analysis was performed in a thermal power plant in Turkey. The study involved determining the thermodynamic properties of 27 node points in a thermal power plant unit, and this was followed by calculating energy and exergy values of every node. Mean exergy costs were calculated by establishing energy and exergy balances of the equipment with respect to the calculated results. Subsequently, lost and damaged energies and exergies were calculated, and exergoeconomic factors were determined. The equipments were compared with each other on a graph based on the obtained results. The maximum rate of exergy loss and cost of exergy destruction corresponded to 79.5% and 886,66 $/h, respectively. The maximum exergy losses in a thermal power plant occurred in the boiler, turbine groups, condenser, heating group, pumps, and auxiliary groups. The highest and second highest law efficiencies of the studied thermal power plant corresponded to 32.3% and 28.5%, respectively. The study also involved presenting suggestions for improvement. Additionally, exergoeconomic analyses were conducted while considering the power plants? investment and equipment maintenance costs. It is expected that the calculation method and the obtained results can be applied to other thermal power plants.

The Effects of High Alkaline Fly Ash on Strength Behaviour of a Cohesive Soil

Contemporarily, there are 16 coal-burning thermal power plants currently operating in Turkey. This number is expected to rise to 46 in the future. Annually, about 15 million tons of fly ash are removed from the existing thermal power plants in Turkey, but a small proportion of it, 2%, is recyclable. Turkey’s plants are fired by lignite, producing Class C fly ash containing a high percentage of lime. Sulfate and alkali levels are also higher in Class C fly ashes. Therefore, fly ash is, commonly, unsuitable as an additive in cement or concrete in Turkey. In this study, highly alkaline fly ash obtained from the Yeniköy thermal power plants is combined with soil samples in different proportions (5%, 10%, 15%, 20%, and 25%) and changes in the geomechanical properties of Ankara clay were investigated. The effect of curing time on the physicomechanical properties of the fly ash mixed soil samples was also analyzed. The soil classification of Ankara clay changed from CH to MH due to fly ash additives. Free swelling index values showed a decrease of 92.6%. Direct shear tests on the cohesion value of Ankara clay have shown increases by multiples of 15.85 and 3.01 in internal friction angle values. The California bearing ratio has seen a more drastic increase in value (68.7 times for 25% fly ash mix).

Determination of economic upper limit of drying processes in coal-fired power plants

ABSTRACTIn this study, the economic assessment of coal drying prior to ga rinding mill process in coal-fired thermal power plants was carried out. In the literature, despite the fact that there are studies regarding drying systems, the advantages and disadvantages of these systems in comparison to each other and the benefits that drying will provide, and the economic factors that are the most important determinants in the practice of the drying system, were not adequately analyzed. In this study, on the other hand, a model was developed to determine the necessary critical cost point in order to identify the appropriate drying system. Through the use of this model, the benefits to be gained from the planned drying system and the financial upper limit required for this investment can be specified. As a model application, eight of the thermal power plants in Turkey were examined. The economic upper limit of a drying system to enable coal to be dried at a rate of 10% was determined through a model study carried out for Catalagzi Power Plant.

Economic Analysis for Rebuilding of an Aged Pulverized Coal-Fired Boiler with a New Boiler in an Aged Thermal Power Plant

Fossil-fired thermal power plants (TPP) produce a significant part of electricity in the world. Because of the aging TPPs and so their equipment (especially boiler), thermal power plants also produce less power than their installed capacities, and there has been power loss in time. This situation affects the supply and demand balance of countries. For this reason, aging equipments such as pulverized coal-fired boiler (PCB) must be renewed and power loss must be recovered, instead of building new TPPs. In this study, economic analysis of rebuilding an aged pulverized coal-fired boiler with a new pulverized coal-fired boiler including flue gas desulfurization (FGD) unit and a circulating fluidized bed boiler (FBB) are investigated in an existing old TPP. Emission costs are also added to model, and the developed model is applied to a 200 MWe pulverized coal-fired thermal power plant in Turkey. As a result, the payback period and the net present value are calculated for different technical and economic parameters such as power loss, load factor, electricity price, discount rate, and escalation rate by using the annual value method. The outcomes of this study show that rebuilding of a pulverized coal-fired boiler with a new one is amortized itself in a very short time.

Solar repowering of Soma-A thermal power plant

In this study, solar repowering of the Soma-A thermal power plant in Turkey is investigated using simulations. The Soma A thermal power plant began operation in 1957 and has served until 2010. In the current situation the installed capacity of the power plant is 44MWel with two units. In the simulations full load and part load operations are considered and compared for three different cases: (1) current case; (2) solar steam generation; and, (3) solar feed water heating. Economic analyses are performed by using the simple payback method. According to the results, solar repowering of Soma A thermal power plant with parabolic trough type collectors can result in 14% power increment at full load operation of the boiler and 14% CO2 decrement at part load operation of the boiler. However, the economic analysis predicts that the payback time of solar repowering is approximately 10years for a CO2 price per ton of 100USD and unit electricity selling price of 0.24USD/kWh.

Assessment of operational and environmental performance of the thermal power plants in Turkey by using data envelopment analysis

In this study, efficiency analyses of the eleven lignite-fired, one hard coal-fired and three natural gas-fired state-owned thermal power plants used for electricity generation were conducted through data envelopment analysis (DEA). Two efficiency indexes, operational and environmental performance, were defined and pursued. In the calculation of the operational performance, main production indicators were used as input, and fuel cost per actual production ( Y) was used as output (Model 1). On the other hand, in the calculation of the environmental performance, gases emitted to the environment were used as output (Model 2). Data envelopment analysis (DEA) is the main instrument for the measurement of relative performances of the decision making units with multiple inputs and outputs. Constant returns to scale (CRS or CCR) and variable returns to scale (VRS or BCC) type DEA models were used in the analyses. The relationship between efficiency scores and input/output factors was investigated. Employing the obtained results, the power plants were evaluated with respect to both the cost of electricity generation and the environmental effects.

Evaluation of Respiratory Functions of Residents Around the Orhaneli Thermal Power Plant in Turkey

The aim of this cross-sectional study was to evaluate the health and respiratory function of residents around the Orhaneli thermal power plant in Turkey. The study was conducted using face-to-face interviews, and respiratory functions were measured with a spirometer. The respiratory functions of 2350 residents, 15 years and older, living in communities near the coal-fired Orhaneli thermal power plant in Turkey were measured. The control group consisted of 469 persons from similar communities without a nearby power plant. The FEV1 (forced expiratory volume after 1 s) and FVC (forced vital capacity) values of the study participants were significantly lower than those of the control group, and residents directly downwind of the plant's smokestack showed greater impairment of respiratory functions compared with residents upwind.

A Simulation Study of Laboratory Scale Ball and Vertical Stirred Mills

AbstractThe aim of this study was to investigate the grindability of solid fossil fuels from a thermal power plant by using a vertical stirred mill and conventional ball mill. The solid fossil fuel sample was obtained from the Zonguldak Catalagzi thermal power plant in Turkey. The sample below 3350 μm (d80 = 2100 μm) was ground in the laboratory scale stirred mill and ball mill. The d80 sizes of the products at the end of grinding periods of 0.25, 0.50, 1 and 4 min in the stirred mill were determined as 190, 102, 78 and 28 μm, respectively. For this purpose, the stirred mill was used at a stirring speed of 360 rpm and with a 6 mm diameter ball. In the ball mill, the d80 sizes of product after 1, 4, 8, 12 and 24 min of grinding were determined as 1802, 1130, 324, 167 and 81 μm, respectively. The results indicated that grinding by means of a stirred mill was much more efficient than grinding with a ball mill in terms of size distribution of the products. The energy consumption of the product with d80 = 78 μm was obtained as 10.53 kWh/t after 1 min of grinding time in the laboratory scale stirred mill. In the same manner, the energy consumption of product with d80 = 81 μm by using the laboratory scale ball mill was 72.73 kWh/t after 24 min of grinding. It can be clearly seen that the d80 size of the fossil fuel reduced from 2100 μm to 1130 μm after a 4 min grinding period in the ball mill grinding tests. However, the d80 size of the solid fossil fuel reduced to 28 μm after the same grinding time in the stirred mill and it was also possible to efficiently obtain size reduction below 100 μm. However, the ball mill grinding process cannot provide this efficient size reduction for longer grinding times. The ball mill grinding experimental results and simulation results showed that they were fairly consistent with each other. The simulation of higher speed mills such as pin type stirrers has been extensively investigated for relatively small‐scale applications by JKSimMet. In this study, the JKSimMet software package was adapted for a stirred mill with the help of the base model of ball milling.

Comparative energetic and exergetic performance analyses for coal-fired thermal power plants in Turkey

The purpose of this study is to analyze comparatively the performance of nine thermal power plants under control governmental bodies in Turkey, from energetic and exergetic viewpoint. The considered power plants are mostly conventional reheat steam power plant fed by low quality coal. Firstly, thermodynamic models of the plants are developed based on first and second law of thermodynamics. Secondly, some energetic simulation results of the developed models are compared with the design values of the power plants in order to demonstrate the reliability. Thirdly, design point performance analyses based on energetic and exergetic performance criteria such as thermal efficiency, exergy efficiency, exergy loss, exergetic performance coefficient are performed for all considered plants in order to make comprehensive evaluations. Finally, by means of these analyses, the main sources of thermodynamic inefficiencies as well as reasonable comparison of each plant to others are identified and discussed. As a result, the outcomes of this study can provide a basis used for plant performance improvement for the considered coal-fired thermal power plants.

Production of glass-ceramics obtained from industrial wastes by means of controlled nucleation and crystallization

Abstract Glass-ceramic materials were produced from coal fly ashes obtained from Tuncbilek and Orhaneli thermal power plants in Turkey without or with the addition of red mud from aluminum production and silica fume. The nucleation and crystallization experiments were carried out on the basis of differential thermal analysis (DTA) results to produce glass-ceramic materials. X-ray diffraction (XRD) analysis of the produced glass-ceramic materials revealed that the main crystalline phases were diopside (Ca(Mg,Al)(Si,Al) 2 O 6 ) and aluminum augite (Ca(Mg,Fe 3+ ,Al)(Si,Al) 2 O 6 ). The microstructure of the glass-ceramic materials was examined by scanning electron microscopy (SEM). Microstructural observation clearly indicated that the crystallization volume increased when the length of thermal treatment time increased. Glass-ceramic samples produced from industrial wastes had high density and microhardness values with a zero porosity and negligible water adsorption. Toxicity characteristic leaching procedure (TCLP) results showed that the produced glass-ceramic samples are non-toxic materials. Glass-ceramic sample showed high resistance to alkali solutions in contrast to acidic solutions. Overall results indicated that the glass-ceramic samples produced from waste materials with several desirable properties that would make them attractive to industrial use in construction, tiling and cladding applications.

Lime based steam autoclaved fly ash bricks

About 10 million tonnes of fly ash are produced yearly as waste from coal fired thermal power plants in Turkey. Only a small portion of this waste is utilized as a raw material in the production of cement and concrete. In this study, Seyitömer power plant fly ash was investigated in the production of light weight bricks. Fly ash, sand and hydrated lime mixtures were steam autoclaved under different test conditions to produce brick samples. An optimum raw material composition was found to be a mixture of 68% fly ash, 20% sand and 12% hydrated lime. The optimum brick forming pressure was 20 MPa. The optimum autoclaving time and autoclaving pressure were found 6 h and 1.5 MPa, respectively. The compressive strength, unit volume weight, water absorption and thermal conductivity of the fly ash–sand–lime bricks obtained under optimum test conditions are 10.25 MPa, 1.14 g/cm 3, 40.5% and 0.34 W m −1 K −1 respectively. The results of this study suggested that it was possible to produce good quality light weight bricks from the fly ash of Seyitömer power plant.

Long-term compressive strength and some other properties of controlled low strength materials made with pozzolanic cement and Class C fly ash

Controlled low strength material (CLSM) is a flowable mixture that can be used as a backfill material in place of compacted soils. CLSM (or flowable fill) require no tamping or compaction to achieve its compressive strength and typically has a load carrying capacity much higher than that of compacted soils, but can be proportioned to allow future excavation. In this study, several different CLSM mixtures containing Class C fly ash (FA) obtained from Soma Thermal Power Plant in Turkey, crushed limestone sand (CLS), and a minimal amount of pozzolanic cement (PZC) were produced. The mass of PZC was kept constant for all mixtures at 5% of FA by mass. The mechanical and physical properties of CLSM mixtures such as unconfined compressive strength, water absorption by capillarity and EP toxicity were investigated by a series of laboratory tests. CLSM mixtures with low PZC contents and high Class C FA and CLS contents can be produced with excellent flowability and low unconfined compressive strengths in the range of 1.16–2.80MPa at 365-days age when re-excavation at later ages might be needed. The results presented here show a new field of application for Soma FA in CLSM mixtures, resulting in great advantages in waste minimization, as well as, conservation of resources and environment.

Preliminary analyses of natural radionuclides in selected Turkish power plant lignites

This preliminary study presents the experimental results concerning the concentrations of selected radionuclides (238U, 232K, 226Ra, 232Th) in Afsin-Elbistan, Can, Cayirhan, Erzurum, Goynuk, Kangal, Orhaneli, Saray, Seyitomer, Soma, Tuncbilek, Yatagan and Yenikoy lignites, which are primarily utilized as fuel for thermal power plants in Turkey. Gamma-spectrometry of 39 representative lignite samples gave results with the following concentration ranges: 8 to 296 Bq/kg for 238U, 3 to 79 Bq/kg for 232Th, 17 to 360 Bq/kg for 40K, and 5 to 130 Bq/kg for 226Ra. The 238U results reported here are higher than other literature values for various world coals, earth's crust and world average.

Use of rubber and bentonite added fly ash as a liner material

In many countries regulations require all hazardous waste disposal facilities to be lined with suitable impermeable barriers to protect against contamination. In this study, a series of laboratory tests on rubber and bentonite added fly ash were conducted. The aim of the tests was to evaluate the feasibility of utilizing fly ash, rubber and bentonite as a low hydraulic conductivity liner material. Type C fly ash was obtained from Soma thermal power plant in Turkey; rubber in pulverized form was waste from the retreading industry. To investigate the properties of rubber and bentonite added fly ash, hydraulic conductivity, leachate analysis, unconfined compression, split tensile strength, one-dimensional consolidation, swell and freeze/thaw cycle tests were performed. The overall evaluation of results have revealed that rubber and bentonite added fly ash showed good promise and a candidate for construction of a liner.