| In recent years,with the further improvement of environmental protection standards,coalfired power plants have achieved ultra-low emissions or even near zero emissions,greatly reducing the emissions of air pollutants and making great contributions to the improvement of our country’s atmospheric environment quality.The limestone-gypsum wet desulfurization system is used as an SO2 absorption unit.The power consumption of high-power equipment such as slurry circulating pump,oxidation fan,and booster fan,a large amount of limestone consumption and a large amount of water evaporation lead to a great increase in the energy consumption of the desulfurization system.At the same time,the pollutant removal performance and energy consumption level are uneven among power plants,units with different capacities and different units with the same capacity.Therefore,it is urgent to establish a system in the industry,which takes into account both the sulfur dioxide removal performance and the desulfurization operation economy.This is particularly important for improving the comprehensive performance of the power plant.Therefore,Therefore,this paper establishes a mathematical model of operating economic indicators of wet desulfurization system to explore the relationship between different parameters and operating economy,and builds a comprehensive energy efficiency evaluation system based on the AHP-grey correlation method.Comprehensive energy efficiency under operating conditions.Firstly,this paper introduces the main components of power consumption,material consumption and water consumption of limestone gypsum wet desulfurization system,and constructs two indexes to measure the desulfurization operating economy by establishing a mathematical model:one is the efficiency ratio,which means the quality of SO2 removed by each unit of kwh of power consumed,and the power consumption includes the power consumed by high-power equipment such as circulating slurry pump,booster fan and oxidation fan.The other is the efficiency ratio,it means the cost per unit mass of SO2 removed,in which power consumption,limestone consumption and water consumption are converted into cost price respectively.According to the collected power plant data,according to the above mathematical model,the desulfurization efficiency ratio and unit desulfurization cost at each time are calculated respectively,which are used for the follow-up operation economic analysis and comprehensive energy efficiency evaluation of the ultra-low emission wet desulfurization tower.Secondly,the Particle Swarm Optimization(PSO)is used to improve the LS-SVM algorithm to optimize the kernel function parameters y and C value,a prediction model with desulfurization efficiency ratio as output parameter is constructed,and the effectiveness of the model is verified.In addition,through the model,the relationship between different input parameters and operation economy is explored by using the method of control variables.The results show that the desulfurization efficiency ratio has a negative correlation with liquid gas ratio and inlet flue gas temperature,and a positive correlation with inlet SO2 concentration and inlet flue gas volume.Among them,the inlet flue gas volume has the greatest influence on the desulfurization efficiency ratio.In the variation range of inlet flue gas volume,the increase range of the average desulfurization efficiency ratio corresponding to the unit liquid gas ratio is 1.00kg/kW·h;The influence of liquid gas ratio,inlet SO2 concentration and inlet flue gas temperature on desulfurization efficiency ratio decreases successively,and the average increase/decrease degrees are 0.69kg/kW·h,0.62 kg/kW·h、0.10 kg/kW·h respectively.Then,combined with the research conclusion of the operation economy of wet desulfurization system,the comprehensive energy efficiency evaluation system of ultra-low emission wet desulfurization system based on analytic hierarchy process grey correlation(AHP-GF)is constructed by using MATLAB software,and the universality is analyzed.The evaluation system comprehensively evaluates the comprehensive performance of ultra-low emission wet desulfurization system from three aspects:operation index,emission index and energy consumption index.Combining the index weight determined by the AHP method with the grey correlation,the weighted correlation degree is calculated as the comprehensive energy efficiency value,and the energy efficiency level is divided into four grades according to the correlation degree.The construction of the energy efficiency evaluation system lays a foundation for the application of energy efficiency diagnosis of ultra-low emission wet desulfurization system,and helps the power plant intuitively understand the weak links of its own energy efficiency and carry out energy-saving operation transformation according to the evaluation results.Finally,the multi-objective evaluation of the ultra-low emission WFGD system of a 1000MW coal-fired unit was carried out from the three aspects:operation index,emission index and energy consumption index.and the comprehensive energy efficiency characteristics of the WFGD system under different working conditions are diagnosed.The operation data of desulfurization system are divided into working conditions according to unit load and inlet SO2 mass flow,and the energy efficiency status is rated.The research results show that under the condition of ultra-low emission,the energy efficiency level of different unit loads is 800MW>600MW>700MW>500MW.The energy efficiency level of SO2 mass flow at different inlets is:5500kg/h>3500kg/h≈4500kg/h. |
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