石灰石-石膏法脱硫设备

Limestone-gypsum method

一． 概述

Summary of a.

石灰石-石膏湿法烟气脱硫工艺是目前应用泛的一种脱硫技术，其基本工艺流程如下：

Limestone-gypsum wet flue gas desulfurization technology is currently the most widely used a desulfurization technology, the basic process is as follows:

锅炉烟气经电除尘器除尘后，通过增压风机、GGH(可选)降温后进入吸收塔。在吸收塔内烟气向上流动且被向下流动的循环浆液以逆流方式洗涤。循环浆液则通过喷浆层内设置的喷嘴喷射到吸收塔中，以便脱除SO2、SO3、HCL和HF，与此同时在“强制氧化工艺”的处理下反应的副产物被导入的空气氧化为石膏（CaSO4•2H2O），并消耗作为吸收剂的石灰石。循环浆液通过浆液循环泵向上输送到喷淋层中，通过喷嘴进行雾化，可使气体和液体得以充分接触。每个泵通常与其各自的喷淋层相连接，即通常采用单元制。

Boiler flue gas after the electric dust, through the booster fan, GGH (optional) after cooling into the absorption tower. In the absorption tower flue gas flows up and is downward flow of slurry by countercurrent washing cycles. Circulating slurry is set up through the shotcrete layer of nozzle to the absorption tower, so that the removal of SO2, SO3, HCL and HF, and at the same time under the processing of "forced oxidation process" reaction by-products are imported air oxidation of gypsum (CaSO4 • 2 h2o), ａnd consume as absorbent of limestone. Circulating slurry through the slurry circulating pump up to the spray layer, through the nozzle atomization, can be used to good contact with gas and liquid. Each pump is usually connected with their respective spray layer, the system usually adopt unit.

在吸收塔中，石灰石与二氧化硫反应生成石膏，这部分石膏浆液通过石膏浆液泵排出，进入石膏脱水系统。脱水系统主要包括石膏水力旋流器（作为一级脱水设备）、浆液分配器和真空皮带脱水机。

经过净化处理的烟气流经两级除雾器除雾，在此处将清洁烟气中所携带的浆液雾滴去除。同时按特定程序不时地用工艺水对除雾器进行冲洗。进行除雾器冲洗有两个目的，一是防止除雾器堵塞，二是冲洗水同时作为补充水，稳定吸收塔液位。

In the absorption tower, gypsum, limestone and so2 reacts this part of the gypsum slurry by gypsum slurry pump discharge, entering the gypsum dewatering system. Dehydration system mainly includes the gypsum hydrocyclone (as a level 1 dewatering equipment), the slurry distributor and vacuum belt dryer.

After purification treatment of flue gas flow through the two levels of demister mist, here will clean the slurry droplets carried by flue gas in the removal. At the same time, according to the specific program of demister with process water from time to time to wash. Demister irrigation has two purposes, one is to prevent the demister blocked, 2 it is to wash water as make-up water at the same time, the steady absorption tower level.

在吸收塔出口，烟气一般被冷却到46—55℃左右，且为水蒸气所饱和。通过GGH将烟气加热到80℃以上，以提高烟气的抬升高度和扩散能力。

In the absorption tower export, flue gas is cooled to 46-55 ℃ or so commonly, and saturated by water vapor. Through the GGH heat of flue gas to 80 ℃ above, in order to improve the lifting height and diffusion ability of flue gas.

最后，洁净的烟气通过烟道进入烟囱排向大气。

Finally, clean through stack into the chimney flue gas into the atmosphere.

石膏法的主要优点是：适用的煤种范围广、脱硫效率高、吸收剂利用率高、设备运转率高、工作的可靠性高、脱硫剂—石灰石来源丰富且廉价。

Main advantage of gypsum method is: the applicable range, high desulfurization efficiency of coal, high utilization rate of absorbent, equipment operation rate, high reliability, high desulfurization agent, the limestone source is rich and cheap.

二． 工艺流程

2. Process

来自于锅炉或窑炉的烟气经过除尘后在引风机作用下进入吸收塔，吸收塔为逆流喷淋空塔结构，集吸收、氧化功能于一体，上部为吸收区，下部为氧化区，经过除尘后的烟气与吸收塔内的循环浆液逆向接触。系统一般装3-5台浆液循环泵，每台循环泵对应一层雾化喷淋层。当只有一台机组运行时或负荷较小时，可以停运1-2层喷淋层，此时系统仍保持较高的液气比，从而可达到所需的脱硫效果。吸收区上部装二级除雾器，除雾器出口烟气中的游离水份不超过75mg/Nm3。吸收SO2后的浆液进入循环氧化区，在循环氧化区中，亚硫酸钙被鼓入的空气氧化成石膏晶体。同时，由吸收剂制备系统向吸收氧化系统供给新鲜的石灰石浆液，用于补充被消耗掉的石灰石，使吸收浆液保持一定的pH值。反应生成物浆液达到一定密度时排至脱硫副产品系统，经过脱水形成石膏。

From the boiler or furnace flue gas after dust under the action of induced draft fan into the absorption tower, absorption tower for counter-current spray air tower structure, integrating absorption and oxidation function, upside is absorbing area, lower for the oxidation zone, after cleaning cycle of the gas and absorption tower in slurry reverse contact. System commonly 3-5 slurry circulating pump, each corresponding to a layer of circulation pump atomization spray layer. When only one unit operation or the load is small, can shut down the 1-2 spray layer, the system still keep high liquid gas ratio, which can achieve the required desulfurization effect. Absorption area upper secondary demister, demister, the free water in the outlet flue gas does not exceed 75 mg/Nm3. After absorbing SO2 slurry into the circulation oxidation zone, in cyclic oxidation zone, calcium sulfite oxidation by blowing air into gypsum crystals. At the same time, absorbed by the sorbent preparation system to supply fresh limestone slurry oxidation system, used to supplement the burn limestone, keep absorbing slurry pH value. Product size reaches a certain density to the by-product desulphurization system, forms through dehydration gypsum.

工艺流程图

Process flow diagram

三． 技术特点

3. Technical characteristics
石膏法脱硫是湿法脱硫的一种。

Wet desulphurization gypsum desulphurization is one of the most commonly used.
但是石灰石/石膏法的缺点也是比较明显的：初期投资费用太高、运行费用高、占地面积大、系统管理操作复杂、磨损腐蚀现象较为严重、副产物—石膏很难处理（由于销路问题只能堆放）、废水较难处理。

But the shortcoming of limestone/gypsum method is obvious: the high cost of initial investment, operating cost is high, covers an area of big, complex system management operation, wear corrosion phenomenon is relatively serious, by-product gypsum difficult to handle (as sales problems can only be stacked), wastewater more difficult.

 该技术与抛弃法的区别在于向吸收塔的浆液中鼓入空气，强制使CaSO3都氧化为CaSO4(石膏），脱硫的副产品为石膏。同时鼓入空气产生了更为均匀的浆液，易于达到90%的脱硫率，并且易于控制结垢与堵塞。由于石灰石价格便宜，并易于运输与保存，因而自8 0年代以来石灰石已经成为石膏法的主要脱硫剂。当今国内外选择火电厂烟气脱硫设备时，石灰石/石膏强制氧化系统成为优先选择的湿法烟气脱硫工艺。

The technology and abandon the difference between the absorber slurry in the blowing air and force CaSO3 oxidation to CaSO4 (gypsum), a by-product of desulfurization gypsum. While blowing air produced more homogeneous slurry, easy to achieve 90% desulfurization efficiency, and easy to control fouling and plugging. Due to limestone is cheap and easy to transport and to save, so since 8 0 s limestone has become the main method of gypsum desulfurization agent. Today's choosing a coal-fired power plant flue gas desulfurization equipment at home and abroad, the limestone/gypsum forced oxidation system become wet flue gas desulfurization technology of choice.

 采用石灰石或石灰作为脱硫吸收剂，石灰石经破碎磨细成粉状与水混合搅拌成吸收浆液，当采用石灰为吸收剂时，石灰粉经消化处理后加水制成吸收剂浆液。在吸收塔内，吸收浆液与烟气触混合，烟气中的二氧化硫与浆液中的碳酸钙以及鼓入的氧化空气进行化学反应从而被脱除，最终反应产物为石膏。

Using limestone/lime as desulfurization absorbent, lime writing broken ground into powder mixed with water to form a absorption of serous, when using lime as absorbent, lime powder after digestion treatment made absorber slurry water. Within the absorption tower, absorption of touch the mixed slurry and flue gas, sulphur dioxide in flue gas with the calcium carbonate in the slurry and the oxidation of blowing air for chemical reaction to be removal, the final reaction products of gypsum.