Limestone Slurry Particle Size Detection Based On The Method Of Laser Diffraction

Limestone-gypsum Desulfurization is the most mature and widely used technology in China.The desulfurization effect directly depends on the granularity of limestone slurry in this method.Therefore,it is positive for power plants to do desulfurization and environmental governance work.Nowadays,the fineness of limestone slurry particles is generally detected by sieving method which is inefficient and unable to detect particle fineness distribution in power plants.The laser diffraction method is one of the most widely used methods with the advantages of high precision,non-contact,and simple measuring device.In this paper,We studied the theoretical model of laser diffraction,the construction of particle fineness measurement system,the inversion algorithm and mainly completed the following aspects of research work:1.Introduced Mie scattering theory,Fraunhofer diffraction theory,analyzed the diffraction light energy distribution function of individual particles and particle groups,and derived the calculation process of light energy coefficient matrix.2.Completed the construction of the particle fineness measurement system,including the construction of the optical path system and the construction of the image acquisition and processing system.Used the CCD camera to complete the particle diffraction image acquisition,and obtained the parameters of each ring of photodetector by derivation calculation.The experiment proves the feasibility of the method,but the lower limit of the particle size measured depends on the size of the CCD sensor.3.Studied the image preprocessing technique,Compared the advantages and disadvantages of Gaussian filtering and mean filtering,median filtering and adaptive median filtering which lays a foundation for the subsequent implementation of particle inversion algorithm.4.Studied the inversion algorithm of particle size,including non-independent mode inversion algorithm and independent mode inversion algorithm,and the characteristics of the two algorithms were summarized.In this paper,the Phillips-Twomey algorithm and the least mean square algorithm are combined to perform particle size inversion,which ensures the calculation speed,accuracy and stability of particle inversion.5.The measurement of the fineness of the limestone slurry particles was carried out on the basis of the particle fineness measurement system,and the experimental results were analyzed.This thesis completed the theoretical and experimental study of particle fineness measurement based on laser diffraction method.The experimental results show that the proposed method can better measure the particle fineness of limestone slurry and lay a foundation for future online testing.