| With the rapid development of Chinese economy,the demand for electricity in production and life is also increasing,and at the same time,in order to achieve the goal of "3060 carbon peak,carbon neutral".Renewable energy power generation has been vigorously developed,but its uncertainty brings challenges to the stable operation of the power grid,so coal-fired power generation is still the main support power source of the power system in the process of new power system construction.Up to now,52%of the installed capacity of coal-fired power generation is still the power source with the largest share in the power structure,however,harmful gases are generated in the process of coalfired power generation,which has a very serious impact on human body and environment.One of the harmful gases is SO2,and the high concentration of SO2 in the atmosphere can form acid rain,which can seriously affect human health and damage the ecological environment.In response to environmental requirements,coal-fired power plants are equipped with desulfurization devices to desulfurize the flue gas emitted from boiler combustion.Limestone-gypsum wet FGD process is widely used in large coal-fired power plants as a relatively mature technology,stable and reliable operation,abundant limestone resources of absorbent,easy comprehensive utilization of by-products and high FGD efficiency.However,at present,this desulfurization method has a low degree of automation and relatively high operating costs.In the background of coal-fired units with a wide range of variable loads,in order to ensure that the flue gas outlet SO2 concentration of the desulfurization system meets the environmental protection emission requirements while achieving stable and economic operation of the desulfurization system.Therefore,this paper takes wet flue gas desulfurization as the research object,takes the economics of the operation process of the desulfurization system as the target,analyzes the reaction mechanism of the desulfurization system,establishes the prediction model of SO2 concentration,establishes the model of energy consumption and material consumption,and finally carries out optimization analysis based on the upper-level scheduling ideas,and its research content can be roughly divided into the following parts:1.The main chemical reaction mechanisms such as SO2 absorption,limestone dissolution,acid-base neutralization,SO32-oxidation and gypsum crystallization in the absorption tower of FGD system and the process flow and roles of each subsystem such as flue gas heat exchange system,SO2 absorption system,limestone slurry preparation system,gypsum dewatering system and wastewater treatment system of FGD system are introduced.2.Based on the chemical reaction mechanism,the main factors affecting the desulfurization efficiency,such as slurry pH,calcium-sulfur ratio,liquid-gas ratio,flue gas flow rate,and SO2 content in flue gas in the absorption tower,were analyzed,and the prediction of the desulfurization efficiency model was carried out using the LSTMXGBoost prediction model based on the actual operation data of a power plant,and the accuracy of the desulfurization efficiency model was verified by using the model evaluation performance index.3.Based on the principle of chemical reaction and material balance,the four aspects of costs in the operation process,i.e.material consumption,energy consumption,emission expenditure and income,are analyzed,and their material consumption and energy consumption models are established respectively to obtain the economic optimization model of the FGD system,which provides the basis for the economic operation of the FGD system.The HGWOP algorithm was also used to solve the economic optimization model of the FGD system under multiple constraints,and the pH value,calcium-sulfur ratio,liquid-gas ratio and economic energy consumption were obtained for the optimal operating cost of the flue gas exported from the FGD system under the condition of meeting the emission requirements.The optimal operating combination of slurry circulation pumps under different load conditions is also determined to provide guidance suggestions for operation... |
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