scholarly journals Prototype Steam Turbine for Solar Power Production

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Kawira Millien

Fabrication of a prototype direct drive steam turbine using locally available materials provides a means to supply power and process heat for off-grid areas, which are not accessible due to rugged terrain. The use of solar power technologies to provide clean power and heat will mitigate environmental pollution and global warming that are caused by combustion of fossil fuels and other carbon-based power sources. The energy density of fossil fuels is higher than that of nonconcentrated solar power, which makes them a better option compared to nonconcentrated solar power sources. The high cost of steam thermal turbines and the limited technical skills on utilization of local materials for steam turbine construction have hampered the realization of potential of producing both small- and large-scale power in Africa. The design of the single-stage blade wheel system solar thermal turbine was done using AutoCAD 2010. The blades were made from encapsulated rice husk particle boards, and the steam casing was made from 0.0015 galvanized black iron sheet. Compensation for more stages was done by sending the fluid exiting from the turbine into the solar collector for reheating. It was coupled to a single-phase generator and gearbox. The rotor was made of galvanized iron tube. The turbine’s average efficiency was obtained as 61.6% and average isentropic efficiency was 55.3%. The combined gearbox and generator approximate efficiency was 54.7%. Locally available heat transfer fluids were used for solar thermal collection. The prototype turbine was designed to produce 500 W of power. It had a heat rate ratio of 0.08. The turbine inlet conditions were as follows: average temperature of 112.8°C, average pressure of 2.7 × 105 Nm−2, average enthalpy of 3156 kJ/kg, and average steam flow rate of 243.3 kg/hr. Outlet conditions were as follows: outlet average temperature of 97.3°C, average steam flow rate of 102.0 kg/hr, average pressure of 1.20 × 105 Nm−2, and enthalpy of 2103 kJ/kg. With use of 6 M sodium chloride solution, the turbine inlet conditions were as follows: enthalpy of 3789.1 kJ/kg at a pressure of 3.0 × 105 Nm−2 and its enthalpy at exit was 2346.3 kJ/kg at a pressure of 1.05 × 105 m−2 which can provide process heat and power for off-grid areas.

2017 ◽  
Vol 10 (4) ◽  
pp. 245 ◽  
Author(s):  
Mohsen Safari ◽  
Fariborz Safari

According to the Fifth Five Year Development Plan, in Iran, renewable resources, under the green horizon scenarios, must provide 5,000 MW of electricity. Among different types of renewable source of energy, there is no shortage of information in Iran, which is located near to zero line (earth’s equator), with about 300 clear sunny days in a year, about setting policies promoting solar energy. Taking into account the availability and benefits of solar energy for Iran, this paper has focused on solar energy.Recent statistics show that, if the current development plans proceed, the capacity of the installed renewable energy systems would reach 2.8GW by 2030. This requires more than 2800 million US dollar investment in 20 years, i.e., 2010 to 2030. Despite the advantages of using solar energy, such as reducing greenhouse gases, it is important to note that solar power is 2.5 to 5 times as expensive as electricity from existing conventional power sources, such as coal and other sources. In order to encourage people to use solar power, there is a need to change our laws and establish an integrated energy regulation, involving tax policy mechanisms to support the deployment of solar energy in Iran. As Iran is dependent upon its fossil fuels, the transition from fossil fuels to renewable, which is a worldwide goal to reduce GHG or CO2 emissions, requires the adoption of a comprehensive policy and integrated regulation nationwide, taking a multidisciplinary approach. This paper exemplifies and considers the 2005 Energy Policy Act and Investment Tax Credit (ICT) for residential energy property, illustrating how solar-energy-regulation could contribute to the sustained development of solar energy. The main purpose is to help the development of sustainable solar energy regulation in Iran.


2019 ◽  
Vol 20 (1) ◽  
pp. 29
Author(s):  
Amiral Aziz ◽  
Kornelis K Ola

ABSTRACTScaling and corrosion are two major problems in operation of the Small Scale Geothermal Power Plant. This paper discusses some results of the study that was conducted to assess the scaling formation in the Kamojang 3 MW Small Scale Geothermal Power Plant. The result of the study concluded that scaling occurred on the nozzle and steam turbine blade where the main minerals contained in sample A (solid) are Tridymate (SiO2), Pyrite (FeS2) and Chlorite (ClO2). While in sample B (sand) where the main mineral contained in the sample is Tridymate (SiO2), Pyrite (FeS2), Plagioclase (Na,Ca)(Si, Al)4O8 and Chlorite (ClO2). The analysis of this scaling was done by XRD (X-Ray Diffraction) method.  Scaling of the nozzle of the steam turbine causes the steam flow rate to decrease, thus lowering the power that the Small-Scale Geothermal Power Plant generates because the power generated by the Small-Scale Geothermal Power Plant is directly a function of the steam flow rate and the enthalpy difference between the inlet side and the outlet side of the turbine. However, scaling does not occur on the exit side of the wellhead KMJ 68 because the concentration of silica is very small that is 0.05 ppm at geothermal steam temperature 200.5°C.Keywords: geothermal steam, scaling, corrosion, Small Scale Geothermal Power Plant ABSTRAKScaling dan korosi merupakan dua masalah yang sangat serius ditemukan pada pengoperasian PLTP Skala Kecil. Tulisan ini membahas sebagian hasil studi yang dilakukan untuk mengkaji pembentukan scaling pada PLTP Skala Kecil Kamojang 3 MW dan pengaruhnya pada daya listrik yang dihasilkan oleh PLTP Skala Kecil. Dari hasil kajian dapat disimpulkan bahwa scaling terjadi pada Nozzle dan sudu-sudu turbin dimana mineral utama yang terdapat didalam sampel A (berupa endapan/padat) adalah Tridymate (SiO2), Pyrite (FeS2) dan Chlorite (ClO2). Sedangkan pada sampel B (endapan lepas/pasiran) dimana mineral utama yang terdapat didalam sampel adalah Tridymate (SiO2), Pyrite (FeS2), Plagioclase (Na,Ca)(Si,Al)4O8 dan Chlorite (ClO2). Analisis scaling ini dilakukan dengan menggunakan metoda XRD.(X-Ray Diffraction). Scaling yang terjadi pada bagian nozzle dari turbin uap menyebabkan laju aliran uap berkurang sehingga menurunkan daya yang dihasllkan PLTP Skala Kecil karena daya yang dihasilkan PLTP Skala Kecil secara langsung merupakan fungsi dari laju aliran uap dan perbedaan entalpi antara sisi masuk dan sisi keluar dari turbin. Akan tetapi, tidak terjadi scaling pada sisi keluar kepala sumur KMJ 68 karena kosentrasi silika sangat kecil yaitu sebesar 0,05 ppm pada temperatur uap panas bumi 200,5oC .Kata kunci : uap panas bumi, scaling, korosi, PLTP Skala Kecil, 


Author(s):  
Alexander Nekrasov

In the investigated high pressure steam turbine, with increasing steam flow rate the exciting aerodynamic forces rise and cause high, but limited vibration of turbine bearings. The tilting-pad journal bearing load and load angle are changing as the steam flow rate changes in turbine with partial arc admission, and accordingly the dynamic characteristics of bearings change. The field experiments results at fossil fuel power plant presented. The aim of experiments was the partial arc steam admission optimization to reducing the effect associated with change of bearing load/load angle. At first, conventional (consecutive) order of valve opening was investigated. In this case, the bearing vibrations are rising while steam flow and valve outlet pressure are increasing. At some “critical point” the vibration level rises stepwise. Situation repeats symmetrically during turbine unloading/loading. In the second part of experiments, the consecutive order of valve opening was changed to “diagonal” one. As a result, the bearing vibration weakly depends on the steam flow rate and its value is significantly lower. Long-term turbine operation shows that “diagonal” steam admission is optimal for this type of turbine. From the analysis of the forces vectors follows that the “critical point” corresponds to static force, which acts in the direction between neighbor tilting-pads. It is contrary to operation and idle modes where this force is acting on pad. The static steam force is bigger and bearing loading is lower at the “critical point”. Numerical investigation of rotor-bearing threshold stability was performed for different bearing loading conditions with exciting aerodynamic steam forces. Two configurations of bearings were included into the model: LBP and LOP — at the “critical point”. Consecutive and so-called “diagonal” orders of valve opening were modeled. Threshold capacity is higher for the “diagonal” valve opening order.


Author(s):  
E. L. Wolf

This is a physics textbook describing, at a college level, the physics and technology needed to provide sustainable long-term energy, past the era of fossil fuels. A summary is given of global power generation and consumption, with estimates of times until conventional fuels will deplete. Sustainable power sources, largely those coming from the Sun directly or indirectly, are described. As sustainable energy must preserve the Earth’s atmosphere and climate, key elements of these topics are included. Key energy technologies in this book include photovoltaics, wind turbines and the electric power grid, for which the underlying physics is developed. Nuclear fusion is described in the context of the Sun’s energy generation, in a brief description of tokamak fusion reactors, and also to introduce ideas of quantum physics needed for adequate treatment of photovoltaic devices. Energy flow in and out of the Earth’s atmosphere is discussed, including the role of greenhouse gas impurities arising from fossil fuel burning as trapping heat and raising the Earth’s temperature. Discussion is included of the Earth’s climatic history and future. Exercises are included for each chapter.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3731
Author(s):  
Simon Kamerling ◽  
Valéry Vuillerme ◽  
Sylvain Rodat

Using solar power for industrial process heat is an increasing trend to fight against climate change thanks to renewable heat. Process heat demand and solar flux can both present intermittency issues in industrial systems, therefore solar systems with storage introduce a degree of freedom on which optimization, on a mathematical basis, can be performed. As the efficiency of solar thermal receivers varies as a function of temperature and solar flux, it seems natural to consider an optimization on the operating temperature of the solar field. In this paper, a Mixed Integer Linear Programming (MILP) algorithm is developed to optimize the operating temperature in a system consisting of a concentrated solar thermal field with storage, hybridized with a boiler. The MILP algorithm optimizes the control trajectory on a time horizon of 48 h in order to minimize boiler use. Objective function corresponds to the boiler use, for completion of the heat from the solar field, whereas the linear constraints are a simplified representation of the system. The solar field mass flow rate is the optimization variable which is directly linked to the outlet temperature of the solar field. The control trajectory consists of the solar field mass flow rate and outlet temperature, along with the auxiliary mass flow rate going directly to the boiler. The control trajectory is then injected in a 0D model of the plant which performs more detailed calculations. For the purpose of the study, a Linear Fresnel system is investigated, with generic heat demand curves and constant temperature demand. The value of the developed algorithm is compared with two other control approaches: one operating at the nominal solar field output temperature, and the other one operating at the actual demand mass flow rate. Finally, a case study and a sensitivity analysis are presented. The MILP’s control shows to be more performant, up to a relative increase of the annual solar fraction of 4% at 350 °C process temperature. Novelty of this work resides in the MILP optimization of temperature levels presenting high non-linearities, applied to a solar thermal system with storage for process heat applications.


Author(s):  
Pourya Shahmaleki ◽  
Mojtaba Mahzoon ◽  
Parmis Shahmaleki

A parallel combination of oil cycle and fossil fuel boiler is utilized in the integrated solar power plant (ISPP) to achieve better efficiency and reduce cost of electricity generation. There are two cycles, oil and steam, in an ISPP. To enhance performance and achieve control optimization more precise simulation for power plant dynamics are needed. In this paper, a dynamic simulation of an ISPP was developed using the HYSYS software. To enhance efficiency and reduce damage to turbine due to flow rate variations of produced steam by oil cycle, the prime control requirement is to maintain the inlet steam temperature and flow rate of the turbine at a constant value. In this paper, to control the complete oil cycle, two fuzzy controllers are proposed: continuous controller and a switching controller. In steam cycle three controllers are proposed for boiler and reboiler heat exchanger. These controllers are used to maintain constant the inlet steam temperature and flow rate to turbine. Simulation results of the integrated solar power plant and the control systems show that the applied control systems can manage the oil and steam cycles in different situations.


1976 ◽  
Vol 98 (3) ◽  
pp. 573-577 ◽  
Author(s):  
J. Krzyz˙anowski ◽  
B. Weigle

In a series of experiments aimed at the visualization of the wet steam flow in the exhaust part of a 200 MW condensing steam turbine a set of periscopes and light sources was used. The aim of the experiment was: 1 – The investigation of the liquid-phase flow over the last stage stator blading of the turbine mentioned. 2 – The investigation of the gaseous-phase flow through the last stage blading at full and part load. The first part of the program partially failed due to the opaqueness of the wet steam atmosphere for the turbine load higher than 10–20 MW. The detailed experimental conditions will be described. An assessment of the primary droplet size will also be given. The preliminary results of the second part of the program will be outlined. The advantages and disadvantages of the equipment used will be discussed.


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