| In the metallurgical,steel,building materials,thermal power,chemical,transportation,and other industries,a large number of particulate dust pollutants are generated.If directly discharged into the atmosphere,it will cause air pollution and endanger human health.Filter type dust removal is highly effective for filtering particulate dust and has an excellent dust removal effect.It is a crucial dust removal technology at present.However,the traditional filter-type dust removal has the problems of insufficient force at the upper of the filter cartridge,and excessive force at the bottom.This makes it difficult to remove the dust on the upper part of the filter material,and the impact of the lower filter material is too significant,which is easy to break.Therefore,the research on the ash cleaning technology of the filter type dust removal has important engineering practical significance.In this study,a self-made pulse injection laboratory bench was used.A ?325 × 1000 mm filter cartridge was selected,and the upper opening diffusers were used to study the dust removal characteristics of the drainage nozzle and the round tube nozzle under the dust-free condition of the filter cartridge.The results show that when the upper opening diffusers are used,the dust removal intensity of the upper part of the filter cartridge will be strengthened and reduce at the bottom.Compared with the traditional pulse injection(without diffuser),The range of high-efficiency jet distance is larger,which can better adapt to the change of dust removal conditions;And it can meet the requirements of the pressure of the dust removal at a lower tank pressure,which can save the pulse gas source;Furthermore,the taper of the diffuser has a reasonable scope of application.Increasing it within a specific range can effectively improve the cleaning strength of the filter cartridge and enhance the uniformity of the filter cartridge.In actual engineering,it is necessary to select the taper of the upper opening diffuser for the strong performance.Comparing the test results of the induction nozzle and the round tube nozzle,since the induction nozzle can induce airflow through the openings on both sides to increase the induced airflow,the pulse airflow velocity and flow rate at the nozzle outlet are different from conventional round tube nozzles,which cause the effect of dust removal is also different.Under the state of the drainage nozzle,the low-pressure area of the filter cartridge are measuring points 1,3 and 4.While the low-pressure area of the filter cartridge are measuring points 2 and 3 when using the round tube nozzle.As the round tube nozzle is widely used in pulse dust removal engineering,this experiment is based on the round tube nozzle.The single-factor experimental study on the cleaning performance of the opening size,installation position(installation height,installation height H2)is also performed.Based on the experimental conditions,the optimal installation height of the upper opening diffuser is 200mm;The optimal installation height H2 of the lower part of the diffuser and the filter plate is 160mm below the position of the filter mouth;Contrast opening 10,16,22,28mm,when the optimal opening size is 16mm,the lowest sidewall pressure of the filter cartridge is 841Pa,and the dust removal strength is the highest.In this article,the dimensionless sidewall peak pressure MO of the filter cartridge measuring points 1,5(respectively from the filter cartridge mouth 100,900mm)and the dust removal parameters(tank pressure P,jet distance L,installation height H2,opening size ?)Dimensionless values were fitted.The fitting formulas are:M0-=0.3606P00.3216H00.58712.171.0922L0?00.1272,M0=0.625P0-0.0936H01.1812L0-0.051?00.3151,Its average relative error(MRE)is 19.17%and 12.02%,respectively,which proves that the formulas can be used to guide the optimization and improvement of the upper opening diffuser.An experiment bench was set up to visualize the flow field of the fluid flowing through the upper opening diffuser.Experiments show that the upper opening diffuser has the function of shunting and diffusing,and the pulsed airflow can be divided into two parts of the inside and outside of the hole.And the shunting and diffusing effect is different from the taper and the size of the opening.The larger the taper,the larger the diffusion flow field area,the larger the dynamic and static pressure conversion of the pulsed airflow at the diffuser position.And the larger the vortex,the greater the dust cleaning uniformity of the filter cartridge.But the larger the taper will also cause the waste of energy;the larger the opening size,the smaller the local flow field that is formed,and the upper opening diffuser cannot play the role of diffusion induction.The lower the opening size,the wider the area outside the diffuser,causing a more gigantic vortex in the local flow field,and the energy dissipation is increased,which is not conducive to dust removal.Therefore,a moderate opening size should be selected for pulse injection.At this time,it is consistent with the experimental rule that the opening size is 16mm,and the best cleaning effect is consistent.Therefore,it can be seen that the performance of the diffuser's shunt and diffusion improves the flow field distribution,thereby changing the ash cleaning characteristics.The single factor experiment and the visualization experiment of the pulsed flow field of the dust removal parameters show that:for the traditional pulse injection,the pulsed fluid is ejected from the nozzle,which acts more on the lower part of the filter cartridge,and makes the upper part of the dust removal ability insufficient.The dust removal ability is too large,and the dust removal effect is not good.The split flow and diffusion of the jet fluid of the upper opening diffuser enhances the dust removal strength at the top of the filter cartridge and reduces the dust removal strength at the bottom,thereby enhancing the dust removal effect of the filter cartridge.The improvement of the dust removal of the filter cartridge has guiding significance. |
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