Study On Filtration Efficiency Of Bag Filter

Have been used for twenty years, bag filters which were produced by old enterprises in. 1980s in China, aged and work difficultly, and non-normal damage of the bags become more and more, which can not satisfy the requirements of environmental protection. So we need renovation badly. Because of the expansion of production and disability of meet the demands of production process the original dust removal system, some enterprises realize the needs of gearing. Because of the venue, funding and time constraints, enterprises look forward to efficient, energy-saving, practical dust modification techniques.As mentioned before, the thesis focuses on the filtering of bag filters and we find that efficiency is what people concern most. Moreover the efficiency formula of classical filtration theory is expressed as implicit function and is inconvenient to be used, however it only can be used under stationary filtration condition and can not work under non-stationary filtration condition. Except these problems how to predict the pressure drop under non-stationary condition is another problem.In order to resolve these problems mentioned above, firstly the author analyzed the change law of filtration efficiency when each factor which affects filtration efficiency changed solely. In the base of this, the testing set of bag filtration was set up. The experiment has been done under stationary filtration condition and non-stationary filtration condition respectively.Under clean filtration stage, firstly the author took the study about the effect of filtration velocity on filtration efficiency. The research shows that there exists a critical velocity. So the point of construction optimization should be concentrated on the filter cylinder. At last from the multianalysis, the regression relation of filtration efficiency was obtained. After comparing this formula with the test data and theoretical calculation, the author drew a conclusion that this formula could be used to predict the filtration efficiency.Under dust filtration stage, the author made a theoretical derivation of filtration efficiency under dust filtration stage. Based on classical filtration theory, according the characteristic of dust filtration, the author set up the mathematical model and obtained a efficiency formula through deduction. It is coincidence with real process. We sum up the efficiency calculation in a clean filtration stage, dust filtration stage and when filtering with peritoneal.Above all, the study of this research project has important meaning for both evaluation of bag filter's performance and prediction of the fibre filtration efficiency.