Modification Of Dust Removal Performance Of Filter Media By Pre-coating Technology

Bag filter as the most widely used dust removal technology has been paid close attention.Selecting the appropriate filter material and optimizing filter structure are the keys to improve the performance of filtration media which contains two main aspects: Increasing the filtration efficiency and decreasing pressure drop.The dust capture efficiency of ordinary needle-punched filter material is lower at initial work,which is impossible to effectively remove fine particulate matters.In our study,pre-coating technology was used for optimizing filter structure to meet the requirements of high dust removal efficiency and low resistance.And an experimental apparatus was established to study the pre-coating filter media performance such as dust removal efficiency and pressure drop across the filter materials.First,TPU particles as pre-coating material were coated on ordinary needle-punched filter material.The influence of heating temperature and time on the behavior of initial resistance and adhesion to fibers were studied by using the method of the factor analysis and orthogonal experiment.The result showed that heating temperature and time as the main factors of pre-coating process greatly affected the performance of pre-coating filter.When heating temperature was 120 ℃ and heating time was 6min,the adhere degree of TPU particles on ordinary needle-punched filter material was close to 100%,and the initial resistance of the TPU pre-coated filter was also at a relatively low level.Therefore,the best experimental condition could be a heating temperature of 120 ℃ with the heating time of 6min.A further study was conducted on dust removal performance of the TPU pre-coating filter.The dust removal efficiency and dust cleaning properties of TPU pre-coating filter with pre-coating thickness of 0mm,0.1mm,0.2mm,0.3mm,0.4mm and 0.5mm were tested by filtration performance test device.Meanwhile,properly analysis and explanation by theory were given in this study.The result showed that TPU pre-coating technology effectively improved dust removal efficiency,and dust removal efficiency and initial resistance increased with the thickness of TPU pre-coating increasing.When L was 0.4mm which was the optimal pre-coating layer thickness,the initial dust removal efficiency of filter material effectively increased and residual resistance could keep relatively stable in a long-term stable process.In order to decrease the higher resistance of TPU pre-coating filter,researches were conducted to improve the filtration performance of TPU pre-coating filter withthe pre-coating thickness of 0.4mm.In the experiment,TPU and zeolite were mixed together as the pre-coating particles in an appropriate ratio of 3:1,and the dust removal efficiency and dust cleaning performance were studied.The result showed that the optimal TPU pre-coating material with good permeability to some extent reduced filtration resistance and kept the dust removal efficiency at relatively higher level,reaching the application requirements.