Study On Cleaning Mechanism And Design Method Of Cleaning System Of Pulse-Jet Bag Filter

With the rapid development of China’s economic and the improvement of people’s living standard, they add to the pollution of the atmospheric environment. Therefore, the request of our country’s atmospheric environmental protection has become more and more stringent. The bag filter has been more widely used because of its advantages of the fine dust purification efficiency. The pulse-jet bag filter is an efficient dust purification equipment of the bag filters. Due to too many advantages, pulse-jet cleaning is the most common and most efficient bag filter cleaning method in the current world. But because there is no the mature cleaning system design method and the pulse cleaning influencing factors do not have a thorough at current home and abroad, they lead to many problems. Therefore, this article studies on the pulse-jet bag filter from the aspects of theory and experiment.In the article, firstly the velocity of the nozzle is deduced by coercible gas heat insulating energy equation; The associated formula is deduced employing jet theory, which described the relationship between air flow, average kinetic energy of each section of jet flow from nozzle to bag opening and nozzle diameter, outlet air velocity and jetting distance. The formulas to calculate the nozzle diameter, outlet air velocity (air pressure of front nozzle), the diameter of limiting ring at the top of bag filter and jetting distance have been proposed based on the relationship between static pressure peak value of cleaning air flow in bag, reverse flow velocity and kinetic energy and flow of jet flow section of bag opening. The theoretical model of cleaning mechanism taking the maximum instantaneous power of bag flow as cleaning intensity index has been achieved.In order to validate the theoretical results, the research launches a study on cleaning mechanism of pulse-jet bag filter. The bag filter applied is 2000mm in length,130mm in diameter.The results of the research indicate that:The filtration velocity and resistance of the fabric bag have the linear relationship. If the filtration velocity and resistance of filter bag are determined by experiment, then the resistance coefficient of the fabric bag can be calculated; The theoretical values and experiment dates of the jetting distance and the diameter of limiting ring at the top of bag filter have a good coherence, the peak pressure can be up to the theoretical value and be the largest; The peak pressure increases with the nozzle diameter, the jetting pressure and the resistance coefficient of fabric bag. The peak pressure does not have much matter with the pulse duration; In the cleaning process of the pulse-jet bag filter, the peak pressure of the entire bag becomes larger as the distance away from the top larger, but the waveform shape, the peak pressure arrival time and the pressure duration are basically the same; Whether having the ejector port or not, the peak pressure have a big difference. The peak pressure of having the ejector port is higher than the peak pressure of not having the ejector port; The air bag consumption does not have much matter with the diameter of limiting ring at the top of bag filter, the jetting distance and the resistance coefficient of the fabric bag. The air bag consumption increases with the nozzle diameter, the jetting pressure and the pulse duration.Based on the results through theoretical and experimental research above, the design method of cleaning system of pulse-jet bag filter is proposed finally.