If an electrostatic precipitator is used, it is difficult to guarantee the investment speed in a short period of time, and it is necessary to take into account the fact that the incremental speed of the large-capacity generator set is relatively fast and the generator set below 50MW is gradually eliminated. Switching to wet dust removal (Venturi water film dust collector), there are problems such as increased water consumption, increased full pressure of the induced draft fan, and long construction period of the dust collector. Therefore, in the transition period, the dust removal equipment urgently needed for the multi-tube dust collector transformation requires moderate investment, meets the overhaul period, is convenient to operate and manage, and meets the national dust emission standards. Through the hot and cold state test research, the composite multi-tube dust collector with inertial sedimentation dust removal and multi-inlet cyclone dust removal integrated dust removal is used for dust removal of power plant pulverized coal boiler. Running tests show that it can meet the transformation requirements. 2. Overview of cyclone dust collector of power plant pulverized coal boiler The dust emitted by pulverized coal boiler of power plant is relatively fine (the medium diameter of soot discharged from solid waste slag boiler is about 30m, the medium diameter of soot discharged by liquid slag boiler is about 18m), used Cyclone dust collectors mainly include: large cyclones, medium cyclones and small cyclones. Large cyclones: 900 cyclones and 410 cyclones. It adopts multi-cylinder combination method, the dust removal efficiency of the solid slag discharge furnace is about 85%, and the pressure loss is generally 700-1 200Pa. The gray blast stone cast slab is installed on the inner wall of the large cyclone. In use, it was found that the inside of the steel plate in the dust collector was louder. The middle whirlwind is a 旋30 cyclone for liquid slagging boilers. Because the emission of soot is relatively thin, the dust removal efficiency is about 65%, and the pressure loss is generally 800-1000Pa. The smoke emission exceeds the standard. There are two types of small cyclones:: 250 axial intake whirlwind and shirt 50 single inlet tangential inlet whirlwind. The former is mostly the original design supporting equipment; the latter is the cyclone for the transformation. The axial air intake cyclone cylinder is a ceramic tube, and the airflow is rotated by an axial multi-leaf baffle (wearing part). By adjusting the length of the exhaust pipe, the exhaust pipe and the ceramic pipe are matched and installed, and the performance is affected. bigger. The dust removal efficiency is generally 70%-80%, and the pressure loss is 800-1000Pa. The tangential (vortex) intake cyclone is used to replace the axial intake cyclone. The dust removal efficiency is about 90%, and the pressure loss is 1 000-1400Pa. abrasion resistance, wear-resistant material of cast iron or steel. Although the power plant has also improved the cyclone dust collector, the dust removal efficiency has been improved, but the dust emission concentration is still relatively high. The existing problems boil down to: the cyclone itself has low dust removal efficiency, poor load adaptability, and wear and blockage. The dust removal performance is even lower; the multi-tube combined airflow distribution is uneven, and the cyclone hurricane causes the dust collection to be mixed back twice; the water seal is not strict or the mechanical ash is used to cause the cold air to leak into the dust collector ash bucket, which intensifies the dust collection. The second back mixing causes the dust removal efficiency to drop. In addition, the reduction of the coal heat value caused by the increase in coal consumption and the general increase in ash content also led to an increase in the original dust holding capacity and dust concentration of the flue gas. 3. Technical improvement points The characteristics of flue gas dedusting of power plant pulverized coal boilers are studied. The composite multi-tube cyclone unit module combination technology is mainly used. Each unit has inertial settlement and multi-inlet cyclone dust removal function. The cyclone sub-unit adopts multi-inlet cyclone, and the cyclone is wear-resistant for the wear problem; the multi-import is used to solve the problem that the cyclone wears off and blocks the ash tube, causing the ash to be poor. The dust removal effect is caused by the shadow airflow eccentricity problem: by strengthening the cyclone The separation of fly ash particle size distribution ability of the sub-inlet channel improves the concentration distribution of soot inlet; the gas ash separation is realized by the lower ash guide tube to prevent secondary back mixing and flue gas flow. 4. Unit thermal test The composite multi-tube cyclone unit is subjected to industrial hot state test on the flue gas dedusting system of the solid-state slag pulverized coal boiler of Qinling Power Plant. The flue gas inlet of the precipitator unit adopts the upper inlet and the side inlet respectively. Form to determine the performance of the precipitator. According to the test results, the dust removal efficiency of the progressive mode is 91.44%~95.12% (corresponding to the resistance of 567~1161Pa), and the dust removal efficiency of the side-entry mode is 91.23% ~ 92.47% (corresponding to the resistance of 500~1060Pa), because the side-entry method is adopted. The dusty flue gas directly rushes to the cyclone inlet, which not only affects the inertial settlement and dust removal, but also affects the dust removal efficiency due to the uneven distribution of airflow. The amount of flue gas treated decreased from 11 020 m3 / h (the amount of gas processed by the design unit) to 7356 m3 / h. Due to the complementary feature of the cyclone dust removal efficiency and the inertial sedimentation dust removal efficiency, the efficiency of the precipitator remained at about 90%. The industrial utilization of Baoji Power plant with a pulverized coal boiler slag liquid 4, 12 oven rated steam load 115t / h, 3,4 furnace is 200t / h. The main copper River coal burning, coal ash content About 30%. The ball mill has a coal powder R90 of about 10%, and the furnace liquid discharge rate is 35%. The tail superheater and the vertical flue inertially capture 10-15% of the coarse soot, so the fly ash discharged from the tail is relatively thin (see Table 1). ). The Shaanxi Provincial Environmental Monitoring Center tested the original dust removal system with a dust removal efficiency of 50%~70%, and the soot discharge concentration seriously exceeded the national standard Shaanxi Environmental Monitoring Center. The results show that the emission concentration of Table 2 meets the national standard requirements. The dust removal efficiency reaches 90%~93% (resistance is about 1000Pa). According to the test results, the calculation of 4 boilers to reduce the amount of soot emissions per hour is 4.95t. The annual calculation of 5 00Ch can reduce the emission of soot to the atmosphere. 24705L Shaanxi Power Plant Pulverized Coal Boiler is a solid-state boiler outside the Baoji Power Plant. It has been transformed into The acceptance test results of four boiler dust collectors of composite multi-tube dust collector are shown in Table 3, respectively meeting the national dust emission standards. Dust removal efficiency project particle size mass distribution mass median diameter Aam geometric standard deviation particle size range <551010 16.516o524.026.511550173301 2 Baoji Power Plant Boiler Dust Collector Reconstruction Test Results Ref. 95 (Part B) Excess Air Coefficient 108132143138 Dust Removal Efficiency 93091 Table 3 Solid State Slag Boiler Dust Collector Reconstruction Test Results 3 Shen Henggen, Yan Yongfa, Ding Shifa, Xu Jinyuan. The wind turbine separator for coal-fired power plant boilers is used to test the wear factors of the Fengqiao Thermal Power Plant of the Huxian Thermal Power Plant. Environmental Process, 1998. 17 (12) 46. Parameters 23474 Shen Henggen, Dang Yirong, Yan Yongfa, Xu Jinyuan. Experimental flow of steam flow in a double inlet cyclone separator / rh11701707575. Journal of Xi'an University of Architecture and Technology, 1997. 29(3): 275277. Flue gas flow rate/m3°h13439083696691751792216465 Shen Henggen, Zhang Wei. Cyclone separator inlet rotary channel gas-dust separation model, Xi'an construction coal ash (application base) 360637.5730.2534.73 Journal of University of Science and Technology, 1998.30 (1): 4749. Excess air coefficient 1.591.531.682.11 dust removal efficiency 94.0293.1693.2994.506 Shen Henggen, Yan Yongfa, Xu Jinyuan, and Party Yirong. Experimental study on the performance of multi-inlet cyclones. Emission concentration / mg.Nm32 186236320391489 National HVAC refrigeration 1998 academic collection. China is a professional manufacturer of condenser drain pump ,oil transport pump ,manifold guage,charging hose,insulation tapes,AC bractek,refrigerant charge scale, embedded pre-installation box,anti-vibrations feet for wall support,outdoor air conditioner rubber ground base bracket,riser,A/C Cleaning Pump Etc. Abltek,Ball Valve Forged,Gate Valve Forged,Water Pump For Air Conditioner Hangzhou Refworld Mechanic&Electric Co.,Ltd , http://www.refworldrefrigeration.com
1. Overview of atmospheric dust pollution in the environment, the power industry, coal powder boiler plant emissions of soot is a major source of pollution. Most of the power plant boilers built before the 1980s use multi-cyclone dust collectors for flue gas dedusting. The dust removal efficiency of these precipitators is relatively low (generally less than 85%). The soot emission concentration cannot meet the current national emission standards. Take Shaanxi Electric Power System as an example (in 1995), the boiler capacity that needs to be modified has more than 3,000 tons (steam), and the amount of treated flue gas is 8 million m3/h (working conditions).