Design And Research Of Superheated Steam Bag Filter Collecting Ultrafine CFB Ashes With Annual Output Of 400,000 Tons

With the development of ultrafine grinding technology, the steam jet mill provides a new process to make CFB ashes harmless and resource recycled. As an important part of the system, superheate d steam bag filter doesn’t have a clear theoretical guidance or standard. Based on the production process of ultrafine CFB ashes processed by steam jet mill with annual output of 400,000 tons, this paper aims at solving structure designing, dust cleaning, high temperature resisting and condensat ion prevent ing problems of the superheated steam bag filter.First, the product ion process of steam jet mill system was analyzed and researched, and the process parameters of the filter were designed with the methods of formulas, experience and analogy. The filter structure model was established.The pulse-jet experiment and industrial experiment were done to study the influence of cleaning intensit y on clea ning effect and life of the filter bag. The effect ive dust cleaning intensit y range of the Fu MeiSi(FMS) bag was built. It shows, the average value of filter bag’s maximum peak pulse pressure in the longitudinal direct ion of 876 Pa can meet the filter’s cleaning requirement. When it exceeds 2713 Pa, the cleaning effect only improves slight ly. Besides, the filter bag will wear once the filter bag’s maximum peak pulse pressure exceeds 5282 Pa. Within this range, the system involved this paper can choose the cleaning pressure of 0.2MPa and the blowing distance of 200 mm.The filter field was simulated by CFD software to study the influence on the temperature field by heat transfer coefficient, steam parameters and the air leakage. The results show that the filter’s internal temperature field is improved and homogenized effect ively as the heat transfer coefficient reduces. When the heat transfer coefficient is less than 0.4W/(m2·K), the filed temperature raises slight ly. The bag temperature has an approximate linear relationship with the inlet temperature. To avoid the bags gett ing burning and condensat ion, the inlet temperature is better between 130℃ and 220℃. Besides, the upper wall of the first room has lower temperature, and it is easier to get condensat ion with the air leakage.According to process characteristics of superheated steam bag filter and the above results of numerical simulat ion, the measures for resist ing high temperature and prevent ing condensat ion were proposed. The materials, equipments selection, installat ion and other issues involved these measures were considered and analyzed. Finally, the main design of the superheated steam bag filter was completed.The above work provides a reference for the bag filter’s design and applicat ion in large scale, ultrafine powder collect ion, high temperature field, high humidit y field and other harsh conditions, with important significance.