Simulation Study On Improvement Of Bag Filter Technology For Biomass Boilers

In view of the problem existing in the engineering application of the bag filter for biomass boilers that due to the uneven distribution of the airflow in the intake flue,the bag filter load of some of the warehouses is too large,which accelerates the wear of the filter bags,and the resulting damage to the filter bags affects the stability of the entire equipment,bag filters are studied and optimized in this paper.The CFD technology is used to simulate and evaluate the airflow uniformity of the bag filter in the optimization scheme.The main contents and results are as follows:(1)Taking the bag filter required for a power plant project in China as the object,design analysis and calculation of bag filter from design conditions,process,structure,pulse cleaning system,filter material,electrical and automatic control system,etc.Design parameters and complete related equipment selection.(2)Aiming at the influence of the number,length and angle of the deflector in the wedgeshaped inlet flue on the uniformity and running resistance of the dust collector,the physical model of the bag filter is established,and the applicable numerical calculation model is selected and verified,and the CFD software has a wedge shape.The air distribution uniformity of the baghouse of the gas flue was simulated.The results show that changing the number and angle of the deflector will have a greater impact on the uniformity of the airflow distribution and the running resistance.Changing the length of the deflector has less influence on the uniformity of the airflow distribution and the running resistance.By adding a baffle,the flow distribution mean square root(RMS)can be reduced from 0.25(pass)to 0.13(excellent)when no baffle is added,and it can be concluded that adding a baffle can improve the uniformity of air distribution.(3)Based on the traditional bag filter,the structure of the filter box is improved,and a new type of modular bag filter is designed.The flat strip filter bag can be used to remove the line from the single filter bag to the single filter bag.The impact of the damage of the small single filter bag on the overall running stability of the bag filter;the replacement of the filter bag in the form of a module group to solve the problem of difficulty in replacing the filter bag.Taking the modular bag filter as the research object,the numerical simulation test was used to study the uniformity of air distribution in each filter box of the dust collector and the internal velocity distribution of the box.The results show that the airflow distribution of the new bag filter is relatively uniform;the gas flow distribution coefficient of each filter chamber is close to 1.00,the average flow unevenness is 0.0431,the mean square root is 0.0432,and the airflow distribution uniformity reaches an excellent level;The average actual filtered wind speed on the surface of the filter bag is about 0.690 m/min,which can provide better filtration conditions.The overall pressure loss of the new bag filter is lower,about 260 Pa,which reduces the energy consumption of the dust collector.Through the above research,a domestic power plant project as case,bag filter improved physical model is set up,choose the appropriate calculation model to optimize the experimental research,it is concluded that used to guide inlet flue gas distribution non-uniform solution and a single filter bag breakage caused serious influence on the stability of the whole equipment running simulation test results of the problem.As the optimized bag-type dust collector in this paper is still in the stage of numerical simulation research,it still needs to pass the physical test research and engineering inspection.