锅炉燃烧系统(2)

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分离及返料装置

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本锅炉采用高温旋风分离器装置，分离装置布置在炉膛出口，分离器入口烟温 850~1000℃。在分离器下部布置了返料装置。分离下来的飞灰经返料装置送回炉膛继续燃烧。返料口离风帽高约1200mm。返料风应接风门及流量计（设计院设计），用来调节风量。经过分离器分离的烟气从分离器出口筒，流经水平烟道进入尾部烟道加热尾部受热面。

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Separation device and back-feeding device This boiler adopt the high-temperature cyclone separator device, the separation device is arranged on furnace outlet, the inlet smoke temperature of separator should be within 850~1000℃. The separator lower part is equipped with the back-feeding device. The separated ash would be sent back to furnace for burning through the back-feeding device. The back-feeding port is about 1200mm far away from the air cap. The back-feeding air should be connected with the air door and flow meter (designed by the design institute), so that the air volume could be adjusted. From the separator outlet shell, the separated smoke would flow across the horizontal flue and enters into the tail flue to heat the tail the heating surface.

分离器出口管

? 2.1 旋风分离器的分类 ? 从形状结构上分，可以分为圆形、方开形和蜗壳形（讲解各类分离器的结构有何不同，优缺点,三代分离器的发展和应用） ? 2.1 The classification of cyclone separator ? The separator can be divided into round type, square type and snail shell type according the shape ? 从有无冷却介上分，可以分为绝热形和水（汽）冷形（讲解受热面设计上的要求） ? The separator can be divided into insulation type and water (or steam) cooling type according to whether has cooling pipes in the wall. ? 从安装位置上分可以分高温形和中温形,通常高温分离器安装在炉膛出口，中温分离器安装在省煤器之后。 ? According to the position where the separator is installed, it is named as high temperature and mid-temperature separator. Usually, the high temperature installed at the outlet of the furnace, the mid-temperature is installed after the economizer.

? 2.2 旋风分器的结构 ? 2.2 The structure of cyclone separator
? 旋风分器由入口加速段（烟道）、分离器壳体和中心管组成。入口加速段烟道和循环流化床锅炉在后墙上的开口对接，另一端和分离器壳体连接，并以切线方向进入分离器。分离器的壳体上部为大直径直段，下部为直径逐渐收缩的锥段，锥口下部和物料循环系统的料腿连接。分离器上部，在正中心有一个烟气引出

管，通常叫中心管，中心管下部插入分离器内部，上面伸出烟道。

? A cyclone separator is consists of a accelerating inlet segment, a crust and a central pipe. The accelerating inlet segment connects with the placket of the furnace on its back wall, the other end connects with the body of the crust on its tangent direction. The upper part of the separator`s crust is a straight pipe of large diameter in size which is made of curved armor plate, the lower part is a cone and its small placket connects with the material downcomer which is settled under it. On the top of the cyclone separator, there is a pipe inserts the body on central position which educe the flue gas, usually, named central pipe.

? 2.3 旋风分离器的除尘机理 ? 2.3 The separating mechanism of the cyclone separator
? 当含尘烟气以高速沿切线进入分离器时，由于贯性、和离心力作用，回固体颗粒会冲涮在分离器壳体上，然后沿壳壁向下滑落进入返料装置，除掉灰尘的烟气从中心管排出，从而起到除尘作用。

? When the flue gas injects into the cyclone separator in the tangent direction, the solid particles will impact on the inner wall of the separator because of the inertia and the centre off force, and then slide down to the material returning device along the incline of inner wall, the cleaned flue gas eject out through the central pipe, so the separating function works.

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2.5 影响分离器分离效率的关键因素 2.5 The factors that influence the separation efficiency of the cyclone separator 对于一个结构固定的旋风分离器，影响分离效率的因素有多个，一个是进入分离器的烟气的速度，一个是伸入分离器内的中心管的长度，一个是中心管的直径,一个是固体颗粒的密度，另一个是颗粒的粒度分布。

? There are several factors that influence the separation efficiency to a cyclone separator which has a fixed structure, they are the speed of flue gas injecting the separator, the length inserted into the separator and its diameter of the central pipe， the density and distribution of granularity of solid particles.
? 提高进入分离器的烟气的速度有助于提高分离效率。提高烟气速度的方法有两个，一是增加入口加速段的长度，延长加速时间，但这样会使锅炉结构庞大，不够紧凑，会增加占地面积和材用量。另一个提高入口烟速的方法是减小入口段截面积，但这样会增加烟气系统的阻力。

? It is helpful to increase the flue gas speed for increasing the separation efficiency. There are two methods to increase the flue gas speed, add the length of the entrance segment, which can prolongs the accelerating time of flue gas, but it will make the structure bigger which will increase the consumption of metal and ground. Another method to increase the flue gas speed is decreasing the cross section o

f the entrance segment, but it will increase the resistance of the flue gas system.

? 增加伸入分离器内中心管的长度或减小中心管的直径都有助于提高分离器的分离效率，但这两种方法都会增加分离器的阻力，增加烟气系统的阻力会增加厂用电消耗，特别是当分离器分离效率高到一定值时，增加效率非常困难，要提高一点效率，对系统阻力会增加很多，因此，分离器的分离效率并不是越高越好，过高会在其它方面造成过多的不利影响。 ? Both increase the length that inserted into the separator and decrease its diameter of the central pipe can improve the separation efficiency, but all that will increase the resistance of the separator, so as to increase the self-consumption of electricity, its is very hard to increase the efficiency, especially, when it has reached to a value relatively high, it will increase the resistance a lot if you increase the efficiency a little. So, it is not that the higher of efficiency the better of a result, it will cause some disadvantages on other aspects when you increase the efficiency excessively.

? 并不是所有的颗粒都能被分离器分离出来，因为分离器是靠惯性和离习力起作用的，其实离心力也是惯性力. 因为惯性和颗粒的质量成正比，当颗粒粒度太小时，惯性非常小就无法被分离出来，所以能不能被分离出来就看颗粒的直径大小。 ? Not all the particles that can be separated from flue gas by cyclone separator, a cyclone separator performs it`s function with the inertia and the off centre force, virtually, off centre force is also a kind of inertia force. Because the inertia force has a direct ratio to the mass, when the particle has a very tiny size, it will has a too small mass to be separated, so for a particle, whether can it be separated due to the diameter of it.

? 2.6临界直径的含义 ? 颗粒被烟气携带进入旋风分离器，大颗粒粒子被分离器分离出来，掉落下来进入物料循环系统，小颗粒从分离器逃逸出去，从分离器里面逃逸出去的最大颗粒，或者说能被分离器分离下来的最小颗业的直径叫做分离器的临界直径 ? 2.6 The meaning of Critical Diameter ? Particles carried by flue gas inject into the cyclone separator, the bigger catch by separator and drop to the bottom, join in the material circulation system, the smaller escape from the separator. The diameter of the biggest particle which can escape from the separator, same as the smallest particle which can be separated from flue gas named as the separator`s critical diameter

? 2.7 粒度分布对分离效率的影响 ? 旋风分离器通常的临界直径在100微米左右，（一张标准打印纸的厚度是75微米），从此可以看出物料的粒度分布会对分离效率影较大，如果待分离的物质小于临界直径的颗粒

份额占的比例较大，分离效率就会很低。 ? 2.7 The efficiency influenced by the granularity distribution ? The ordinary critical diameter of a cyclone separator is approximately 100 micrometer, (the thickness of a standard printing paper is 75 micrometer).So, we can get a result as that the granularity distribution will influence the separation efficiency seriously, if the tiny particles whose size small than the critical diameter has a big proportion, then, the separation efficiency will be very low.