1、动态分离器技术介绍Introduction of Dynamic Classifier Technology随着电力事业的快速发展，世界各国对电厂环保的要求越来越高，许多机组都在使用低 NOx 排放技术。为了降低 NOx 和飞灰排放量又不增加运行成本，作为锅炉系统重要辅机的磨煤机也相应进行了技术改进，采用了动态分离器技术。With the rapid development of electric power project,most countries begin to think much of the environment. As a result, many units are in
2、corporating infurnace low NOx technology. For reduceing the NOx and ash and without disposal cost, pulverizer that is one of the most important assistant equipment of the boiler system have been improved and equipped with Dynamic Classfier .HP 磨煤机配套的动态分离器装置主要包括以下几个部分：The primary components of the Dy
3、namic Classifier are:1. 轴承和驱动装置 Bearing and Drive Assembly2. 变频电机和涡轮蜗杆减速器 Variable Frequency Motor and Worm Gear Reducer 3. V 带 V-Belt4. 变频器 Pulse Width Modulated Variable Frequency Drive(VFD)5. 转子装置 Rotor Assembly动态分离器使用一对脂润滑角接触球轴承，轴承放置在结构件制成的轴承座中，上、下轴承各有一个热电阻用于监测轴承温度。为了保护轴承，上、下各有一个油封。迷宫气封的设计也是为了防止
4、粉尘进入驱动装置。The Dynamic Classifier use two grease lubricated angular contact ball bearings installed in fabricated steel housing.There are two thermocouples to monitor the temperature of the two ball bearings.To protect the bearings,upper and lower oil seals are used.Labyrinth design air selas are also
5、 used to seal the drive assembly from coal dust.变频电机和涡轮蜗杆减速器通过联轴器连在一起，变频电机通过变频器改变频率从而改变转速。涡轮蜗杆减速器输出轴上安装主动轮，通过皮带带动与转子装置连接在一起的从动轮，从而使转子转动。转子的旋转方向为从磨煤机上方往下看为顺时针方向。The Variable Frequency Motor and Worm Gear Reducer are connected by a coupling.The frequency of the motor is changed by the VFD and then the
6、 speed of the rotor can be changed.A driver sheave is assembled at the output shaft of the worm gear reducer,and it drives the drived sheave which is connected with the rotor assembly ,and so the rotor can rotate.The Dynamic Classifier Rotor is designed to rotate in a clock-wise direction when viewe
7、d from above the mill.变频器采用成熟技术制成，与机械变速相比，变频器几乎不用维护，可靠性很高。VFD have high reliability using proven technology with little or no required maintenance as compared to mechanical speed control.转子采用耐磨合金钢制成，整体锥形结构，设计寿命超过 50000 小时。The rotor design is a multi bladed rotor with a basic conical shape.It is fabr
8、icated from an abrasion resistant alloy steel and designed with lives exceeding 50,000 hours.带动态分离器 HP 磨煤机的工作理：HP 磨煤机的主要功能是将直径小于等于 38mm 的原煤研磨成 0.075mm 左右的煤粉，供锅炉燃烧。热一次风（用来干燥和输送磨煤机内的煤粉）从磨碗下部的侧机体进风口进入，并围绕磨碗毂向上穿过磨碗边缘的叶轮装置，旋转的叶轮装置使气流均匀分布在磨碗边缘并提高了气流的速度，与此同时，煤粉和气流就混合在一起了，气流携带着煤粉冲击固定在分离器体上的固定折向板。颗粒小且干燥的煤粉仍逗
9、留在气流中并被携带沿着折向板上升至分离器，大颗粒煤粉则回落至磨碗被进一步碾磨，分离器体下部的固定折向板使煤粉在碾磨区域进行了初级分离。Operation principle of HP mill with with Dynamic ClassifierThe primary function of HP mill is to grind coal from diameter 38mm to diameter 0.075mm and send ground coal to boiler for burning.The hot primary air enters mill from the ai
10、r inlet of millside and pass through the vane wheel assembly encircling the bowl hub.The rotating vane wheel assembly directs, equalize and accelerates the primary air.And at the same time the coal and air mix.As the coal-air mixture rises up through the separator body ,the initial classification oc
11、curs when the heaviest particles lose their momentum and fall back to the bowl for regrinding.煤粉和气流上升，通过分离器体进入旋转的叶片式转子，在转子外沿处，气流和煤流相互作用，转子会阻止较大颗粒通过，使较大颗粒返回磨碗进一步碾磨，而细度合格的煤粉则可以通过转子排出磨煤机。通过变频器和变频电机可以改变转子的转速，通过改变转子的转速可以调整煤粉的细度。the coal-air mixture rises up to through the spinning rotor.At the outside fa
12、ce of the rotor,the air and the coal stream interact with the rotor.The rotor rejects the larger particles and sends them back to the grinding zone for further size reduction while the samller particles are permitted to pass through the rotor and exit the mill through the discharge valves.Finess is
13、varied by changing the speed of the rotor.This is done by means of avariable speed motor and variable frequency drive.带动态分离器的磨煤机由于内循环负荷比静态分离器小，所以能够提高磨煤机出力，这是由于分离效率提高实现的，就是说避免了细小颗粒（粒度小于200 目的）不必要的重新碾磨次数，这样合格的煤粉就可以较快的排出磨煤机。也就是说：相同的煤质和细度要求下可以提高磨煤机出力；或者相同的煤质和出力要求下可以提高煤粉细度。The addition of a Dynamic Class
14、ifier to a pulverizer results in an increase in capacity due to a reduction in the recirculation load created by the classifier. The reason for thes increase in capacity is the change in classification in efficiency.That is ,unnecessary over-grinding of the very small particles (those less than 200
15、mesh ) is reduced, thus properly sized particles are discharged quicker with the Dynamic Classifier. The increase in capacity can be utilized in one of two ways: an increase in coal flow for constant coal properties and constant tineness,or increased fineness capability for constant coal properties
16、and coal flow.HP 磨煤机采用动态分离器后煤粉颗粒分布关系：Distrubuting of coal ground by HPmill with Dynamic Classifier 序号No.单位unit通过 200 目筛子through 200 mesh通过 100 目筛子through 100 mesh50 目筛子剩余through 50 mesh1 % 80 98.2 0.052 % 85 99.5 0.003 % 90 100.00 0.00HP1003/Dyn 磨煤机动态分离器技术参数HP1003/Dyn mill Dynamic Classifier technic
17、al data1. 变频电机额定功率 45kWRated power of variable frequency motor 45kW2. 变频电机频率 16.750HzFrequency of variable frequency motor 16.750Hz3. 转子转速 30130 rpmSpeed of rotor 30130 rpm4. 煤粉细度 R 90=5%35%Coal finess R90=5%35%动态分离器的操作和维护动态分离器的控制要根据给煤量和现场调试时绘制出的校准曲线来确定转子转速。电厂 DCS 系统控制变频器，变频器改变变频电机转速，从而改变动态分离器转速。The
18、 control of Dynamic Classifier is based upon the raw coal feed rate to the pulverizer and a calibration curve developed at the plant during Dynamic Classifier commissioning . Distributed Control System (DCS) controls VFD and VFD changes the speed of the variable frequency motor,and then the speed of
19、 rotor can be changed.动态分离器的结构简单，维护方便。电机轴承、动态分离器轴承、涡轮蜗杆减速器轴承的润滑、减速器润滑油更换和皮带的涨紧等一般一年进行一到两次。皮带、油封和转子的更换一般三到五年进行一次。Dynamic Classifiers frame is simple,and its maintenance is very convenient. Grease lubrication of the motor bearing, Dynamic Classifier bearing,worm gearbox bearing and oil changes for the
20、 worm gearbox occur two or three times per year.The belt ,oil seal and rotor replacement occur approximately three to five years intervals.总之，与静态分离器相比，带动态分离器的 HP 磨煤机主要有以下优点：In all, relative to Static Classifier, HP mill equipped with Dynamic Classifier has some excellence as follows:1. 提高煤粉均匀性指数。煤粉均
21、匀性指数可以达到 1.20 以上。1. to increase the ground coal uniformity index.The uniformity index can be 1.20.2. 同样的煤质和出力要求下可以提高煤粉细度，煤粉细度可以达到 200 目通过率 90%以上。2. to increased fineness capability for constant coal properties and coal flow. The fineness can be 90% through a 200 mesh screen.3. 提高磨煤机效率。由于磨煤机效率的提高，在相同
22、的煤质和煤粉细度要求下，可以提高磨煤机的出力。3. to increase the efficiency of mill.The mill capacity can be increased for constant coal properties and coal fineness due to the increasing of the efficiency.4. 实现煤粉细度调整自动化。由于采用了变频器和变频电机驱动，可以通过 DCS 控制变频电机频率，改变转子转速，从而实现煤粉细度的调整。4. to achieve the autocontrol of the coal finenes
23、s. Because of the adoption of VFD and variable frequency motor, the frequency of motor can be changed through DCS and the rotor speed can be changed, and then the coal fineness can be changed.5. 在同样的出力和细度要求下，可以降低风煤比，从而降低一次风率，可以更好的满足燃烧劣质煤种的系统需要。5. to reduce the ratio of air to coal for constant coal
24、capability and coal fineness, and reduce the primary air ratio.So the mill can meet the system demand with bad raw coal.HP 磨煤机长期以来以其优良的性能、紧凑的结构和方便的操作维护受到国内外用户的喜爱，其动态分离器技术也秉承了 HP 磨煤机一贯的优点，在国内外火电机组上发挥着举足轻重的作用。HP mill have been in favour with inland and overseas clients for a long time because of its excellent performance,compact frame and convenient operation and maintenance. And the Dynamic Classifier also inherits the strong suit of HP mill,and exerts at fire power units of the world.上海重型机器厂有限公司设计研究院Shanghai Heavy Machinery Plant Co., Ltd(SHMP)Design Academe2005-12-26
