Research On Soft Measurement Method Of Sulfur Dioxide Concentration At The Inlet Of Desulfurization Absorption Tower Of Coal-fired Unit

China is not only an economic power,but also a large country that is responsible for the ecological environment and resolutely maintains environmental protection policies.my country has put forward higher requirements for strengthening environmental protection and governance of the ecology,especially for thermal power plants in the power industry,putting forward strict standards such as sulfur dioxide（SO₂）emissions not exceeding 35mg/m³.Aiming at the problems of time lag and data distortion in the purging process of the sulfur dioxide concentration measuring instrument in coal-fired power plants,this paper uses the least square support vector machine（LSSVM）and the long short-term memory network（LSTM）soft-sensing model to study.Through a variety of correlation analysis methods such as mutual information,the auxiliary variables with higher correlation with sulfur dioxide are analyzed as the input of the soft sensor model.Secondly,optimization algorithms such as particle swarm optimization are used to optimize the model parameters to determine the optimal parameter combination of the model and reduce the training cost of the model.Finally,the output sulfur dioxide concentration of the soft-sensing model is compared with the actual sulfur dioxide concentration,and the better model is selected as the best soft-sensing model.The experimental data in this paper selects DCS data from a power plant in Yulin,Shaanxi for simulation experiments,and the experimental data is true and effective.The simulation experiment results show that the soft-sensing model established through algorithm optimization and other methods have different prediction effects.Among them,the results obtained by using the LSTM model are closer to the actual sulfur dioxide concentration under the same conditions except for the different soft-sensing models.The experimental results It shows that the accuracy of this model method is much higher than other models.Through the various models proposed in this paper and continuous experimental comparison,the PSO-LSTM model based on mutual information has higher soft measurement accuracy than other models.Under the premise of ensuring environmental protection standards,it can realize soft measurement and realize the pollution of sulfur dioxide.The precise control of the system ensures stable operation of the system,ensuring economic and environmental benefits.