Study On Thermal Performance And Integrated Mechanism Of Solar-aided Coal Fired Power Plant

As a type of new energy which can be utilized in large-scale, the solar energy has got rapid development. Solar thermal power generation is a typical way to use solar energy. In some extent, the increased investment to avoid solar radiation volatility is an obstacle to the development of large-scale solar thermal power generation. Solar trough collector technology is a kind of mature thermal power generation which has been operated foreign in several decades. Coal-fired power plant has wide temperature range, stable and controllable loads, its different temperatures requirement match well with the temperature provided by solar trough thermal collector system. Thus, the solar-aided coal fired power generation through utilizing the solar energy to replace some extraction of turbine can integrate the solar trough collector system with coal-fired thermal system. It not only can use the solar energy, but also can decrease the coal consumption. Solar/thermal hybrid system is a complex energy system. The research of this complement system should focus on the coupling relationship and corresponding status characteristics between solar collector systems and coal-fired power plant thermal system.The aim of this thesis is to study the thermal characteristics of solar-aided coal fired power generation, besides, explore the operation properties of solar trough collector system and thermal characteristics and operation mode in complement generation. The main contents and conclusions include:Firstly, exploring the complementary mechanism and principal of solar trough collector systems and coal-fired power system based on the different energy demand characteristics of the two systems. Building the thermodynamic model of solar/thermal hybrid system and doing basic thermodynamic analysis, the results indicate solar energy can achieve better matching with coal-fired power plants. When the solar collector field can provide enough heat and it has higher collector temperatures, replacing high pressure extraction can improve the economy directly.Secondly, based on the solar resource characteristics of the demonstration plant station site, thermal collector characteristics of solar trough collector system at design conditions, changes in the array pitch and varies of axial mounting angle, loses vacuum of the tube collectors and other conditions have been analyzed. What's more, the changes in wind speed, ambient temperature and other factors on quantitative collector system efficiency have also been investigated. Then, the solar power capacity of different technical route and system collector characteristics have been studied through analyzing the generation characteristics of three typical solar power systems under the irradiation conditions in demonstration plant Thirdly, introducing the basic information including station site, layout planning, installed programs, key device parameters indicators of the first complementary demonstration generation of China which is on the basis of existing international standards of solar trough thermal power plant. This demonstration projects not only can provide technical support for the development of large-scale solar-aided coal fired power generation and verify the matures and reliability of domestic solar thermal power technology, but also can get first-hand construction, operation and management experience which can laid a solid technical foundation for the implementation of the follow-up commercial plant. Finally, based on the built solar-aided coal fired power generation, the impact mechanism on the stability of operation caused by some critical parameters can be understand through the actual test data analysis system.Furthermore, the analysis model of solar share and each share enthalpy flow of energy cost in solar/thermal hybrid system have been built. Based on the basic principles of thermoeconomics, this model has considered the economic costs of each energy flow as well as non-energy costs of each subsystem. It can be used to analyze and validate the thermal performance of demonstration power plant. Meanwhile, taking the solar-aided coal fired power generation with thermal storage system assuming as the research object, the operation mode as well as the flow distribution characteristics of demonstration plant with thermal storage system in typical weather conditions and load conditions.Finally, the power generation and power supply characteristics of three typical solar thermal power generation systems in the same installed capacity and collector area has been studied. Taking the total investment, operation and maintenance costs, fuel costs, interest rates into consideration, the economic characteristics of the corresponding technical route has been analyzed through the unit generation cost method and the internal return rate method. From the investment perspective, analyzing China's current solar/coal hybrid system industries and the corresponding distribution of investment costs through detailed industry research. Besides, the assess of solar thermal industry including materials, fuel price change risks, changes in the market risk, technology risk, risk assessment and preventive measures has been conducted. The policy recommendations about the development of solar-aided coal fired power generation has been proposed.By studying the integrated mechanism and thermodynamic properties of solar aided coal-fired power plant, the system thermodynamic properties mechanisms of were studied in the changes of trough solar collector system baseline conditions, the array spacing, and the mounting angle and so on. It can solve the problem of trough solar collector system design optimization. The research results have been used in the first solar aided coal-fired power plant in China and the stable operation of the collector system has been achieved. It is the first one whose outlet temperature is stable and can reach to the393?. Due to highlight progress in theoretical research and demonstration projects, the author's company is chosen as editor-in-chief to write the first national design standards in trough solar field, that is, trough solar thermal power plant design specifications.