Numerical Simulation Of Working Process Of Dust Collector Sleeve Double Layer Filter Bag

At present,with the rapid development of economy and society of our country,all related industries put forward higher requirements for the processing capacity of bag filter.How to improve the handling capacity of the bag filter is a difficult problem to be solved in engineering.Although increasing filter bag length can improve the processing capacity of the flue gas,but as the length of the filter bag increases,the height of the dust collector box will also increase,the overall stability of the equipment may decrease,and the steel consumption of the equipment will also increase accordingly.Secondly,after the filter bag lengthens,the air flow velocity near the bottom of the filter bag is higher and the filter bag is easily damaged.The unevenness of the air volume handled by each filter bag was aggravated and the local dust accumulation was serious.Therefore,the research and application of a new sleeve type double layer structure filter bag is one of the important technical approaches that are expected to solve the above problems.The sleeve type double layer structure filter bag(hereinafter referred to as the double bag)is to add a smaller and inverted internal filter bag inside the traditional cylindrical filter bag,which the outer bag outer filter and inner bag inner filter.The unique structural features of the double layer bag can effectively avoid the defects of increasing the size of the bag filter,weakening the strength and rigidity of the dust collector,or increasing the amount of steel,to increase the area of filter bag filter area(such as increasing the number of filter bag or increasing the length of filter bag).It is no necessary to make great changes to the overall design frame of the bag filter and more suitable for the design optimization and technical transformation of the existing bag type bag filter by the local reinforcement after the related accounting and the replacement of the new structure filter bag.At the same time,the use of double layer bag can make the bag filter have more redundancy to meet the requirements of wider operating conditions.If our country takes the lead in tackling double layer bag technology,it will be advantageous to occupy the advantage in the international bag filter market competition.At present,there are few studies on double layer bag at home and abroad.No clear conclusions are drawn about the selection rules of double layer bag and the operation rules of double bag filter.In this paper,CFD technology is used to study the working process of commonly used single-barrel filter bag(hereinafter referred to as ordinary bag or ordinary filter bag)and their modified double layer bag.By constructing the numerical model of the double layer bag filter and cleaning process,the internal flow field of the double layer bag filter was numerically simulated and compared with the ordinary bag filter,and some rules were obtained,which could be used for the double layer bag.And provide reference for the structural design and optimization of double layer bag filter.The specific research content and results are as follows:(1)Based on a physical model simplified by a design institute based on the prototype of the product,a numerical model for the filtration process of the double layer bag filter was established.Comparing with the numerical model of ordinary bag filter,the relation between the increase of filter capacity and the increment of filter capacity of double layer bag compared with ordinary bag filter was studied.The internal flow field of double layer bag filter and the filter resistance of bag filter of double layer bag filter were studied.Changes.The relationship between the utilization ratio of the double layer bag inner filter bag and the height and diameter of the inner filter bag was explored,and some methods for improving the utilization rate of the inner filter bag were proposed.(2)Using the physical model of a design institute as a reference,a numerical model of the double layer bag dust collector pulse cleaning cleaning process was established.Compared with the ordinary bag pulse jet cleaning process,the similarities and differences of the double layer bag and ordinary bag cleaning process were analyzed.The height and diameter of the bag inside the double layer bag were changed respectively,and the influence of the height and diameter of the inner bag on the double layer bag cleaning process was studied.(3)Determine the selection rules of the double layer bag by considering the double layer bag filtration and cleaning processThe use of an inner filter bag with a small height-to-diameter ratio is beneficial to the filtration process of the double layer bag filter,and can improve the utilization of the inner filter bag.The use of an inner filter bag with a small diameter and low height is beneficial to the cleaning process of the double layer bag filter.Both processes tend to have a low height of the inner filter bag,but there is a conflict in the requirements for the inner bag diameter.To balance the conflict,a filter bag with a diameter of 0.08 to 0.1 m and an aspect ratio of less than 50:1 is recommended as the double layer bag's inner filter bag.