Thermoeconomic Cost Analysis And Optimization Based On Conventional Pulverized Coal-fired Power Plants And CO₂ Emission Control Systems

The actuality of the energy industry in china is that the average efficiency of energy conversion is very low and natural environment is damaged heavily. Emission of greenhouse gas, such as CO₂ from coal combustion is one of the important reasons for global warming. Research on the CO₂ emission control has been a worldwide topic. In this thesis, the"CO₂ emission control systems"and"improving the efficiency of conventional power plants"are selected as the analysis objects. The base research system is oriented to a 300MW N300-16.7/537/537-1 pulverized coal-fired power plant located in Hunan Province, the main aim is to attain the sustainable development in energy, economy and environment. The thermodynamic simulation of the analyzed plant is achieved and a approach to evaluating and optimizing the energy systems is developed based on the structural theory of thermoeconomics.Basing on the simulator, by varying the operating parameters, loads and system environment conditions, this simulator can reproduce the cycle behavior for different operating conditions with relative errors less than 2% compared with those obtained from the performance tests. Based on the thermodynamic simulation, the thermoeconomic model and thermoeconomic cost model based on the Fuel-Product definition are used to quantify the productive interactions among different components of the plant. The thermodynamic process of cost formation and the distribution of the resources throughout the plant can be analyzed.For analyzing the"CO₂ emission control systems", a reconstruction work on the base power plant has been finished to control the CO₂ releasing. There were two reconstruction methods: O₂/CO₂ reclycle combustion and MEA scrubbing. The techno-economic evaluation between the two retrofitted systems has been studied by using the simulator and the methodology of the structural theory of thermoeconomics. The cost of electricity and the CO₂ avoidance cost were chosen as the evaluation indexes. The results show that the O₂/CO₂ reclycle combustion one is more economical.A modification and improvement work has been done on the Local-Global decomposition optimization (LGDO) method. Using this improved LGDO method, the base power plant was optimized. When comparing the results obtained from the LGDO method and a conventional local optimization method with those obtained from a global optimization, the LGDO method can get more exact results than the conventional local optimization method. And the convergence speed of the LGDO method is very fast.