AF泡沫泵兩種強制氧化裝置性能比較

(1) FAS霧化空氣泡粒徑較ALS要大些，F(xiàn)AS的傳質(zhì)效率在很大程度上依賴于浸沒深度，其次是氧化區(qū)單位體積的氧化空氣流量。如罐體液位較低，噴氣嘴的浸沒深度就低，要獲得相同的氧化效果就必須鼓入相對較多的空氣。
    FAS的最小氧化空氣流量一般不低于最大流量的30%~40%。而且只要罐體內(nèi)有漿液，氧化鼓風(fēng)機就不能停運，否則噴管易發(fā)生堵塞。FAS的機械構(gòu)件較多，又都在罐體內(nèi)，發(fā)生堵管的可能性大，維護工作顯大，因此要謹(jǐn)慎選用。
    (2)ALS產(chǎn)生的氣泡較細，而且降低了對沒沒深度的依賴性。為了保證ALS的傳質(zhì)性能，氧化空氣流量和攪拌器的分散性能應(yīng)四配。若氧化空氣流量太大且超過液流分散能力時會導(dǎo)致大量氣泡涌出，嚴(yán)重時攪拌器葉片吸入側(cè)也匯集大量氣泡，使得葉片輸送流量下降。
    (3)由于ALS噴氣管口徑較FAS大得多，其氧化空氣流量可大幅度調(diào)低而不用擔(dān)心噴氣管堵塞，因此可以采用多臺較小容量的鼓風(fēng)機并聯(lián)運行。
    5.先進的氧化空氣布氣方式特點

（1）氧化性能高;(2)氧化空氣用量少;(3)氧化空氣分布均勻;(4)便于維修。

二、攪拌器分類及組成

攪拌器是用來攪拌漿液、防止?jié){液沉定的攪拌設(shè)備。吸收塔漿池攪拌的目的除了懸浮漿液中的固體顆粒外，還有以下作用①使新加入的吸收劑漿液盡快分布均勾(如果吸收劑漿液直接加入罐體中)，加速石灰石的溶解:②避免局部脫硫反應(yīng)產(chǎn)物的濃度過高，防止石膏垢的形成，③提高氧化效果和越來超鄉(xiāng)石膏結(jié)晶的形成。脫硫攪拌器根據(jù)安裝位置不同分為側(cè)進式批拌器和頂進式攬拌器。兩種攪拌器都是由軸、葉片、機械密封、變速箱、電動機等組成。頂進式攬拌需采用漿罐、地坑頂部安裝方式，脫碗系統(tǒng)中多數(shù)罐池(如石灰石漿罐，過濾水地坑等)采用混進式攪拌器。吸收塔漿池中的攪拌器可以采用頂進式或者側(cè)進式，其主要取決于吸收塔和吸收塔漿池的結(jié)構(gòu)。側(cè)進式攪拌器采用罐體外壁安裝方式，如圖3-30、圖3-31所示。

1. 攪拌器設(shè)計考慮的因素

攪拌器設(shè)計考慮的因素有保證攪拌效果，保證氧化效果、低能耗、材料選擇及密封。
    2.結(jié)構(gòu)材料
    外殼:鑄鐵外殼及頂部通過法蘭連接在驅(qū)動器上，底部用螺栓固定在攪拌器支座上。螺栓材料為碳鋼外鍍1.4529不銹鋼涂層。
    軸密封:非沖洗單向作用的機械密封系統(tǒng)，有機械密封關(guān)斷裝置。
    3.脈沖攪拌系統(tǒng)
    德國魯奇公司應(yīng)用于吸收塔漿池和事故漿罐的攪拌裝置由脈沖懸浮泵和脈沖懸浮裝置是用脈沖懸浮漿泵從漿池中抽取漿液，加壓后經(jīng)布置在漿池中的懸浮管噴向漿池底部，以起到攪拌漿液的作用，其原理圖可參見圖3-32。其中，池分離器的作用是防止上部氧化區(qū)和下部反應(yīng)池之間的混合。這種攪拌裝置無機械轉(zhuǎn)動部件，不存在螺旋槳出現(xiàn)故障時需停機排漿檢修的問題。另外，只要漿池中有漿液，螺旋槳攪拌器就不能長時間(一般不超過4h)停運。但采用脈沖懸浮裝置，F(xiàn)GD系統(tǒng)7天停機時間內(nèi)，再次啟動攬拌泵10min后可將已沉淀的漿液重新攪動起來，因此可以降低FGD備用時的電耗。缺點是造價高于螺旋槳攪拌器，
    三、向吸收塔注入石灰石漿液的部位
    通常，吸收塔有3個地方可選作注入石灰石漿液的部位:①當(dāng)反應(yīng)罐不明確劃分氧化區(qū)和中和區(qū)時，直接向罐體注入石灰石漿液，如圖3-10所示的JBR反應(yīng)器;②當(dāng)將反應(yīng)罐劃分成氧化區(qū)和中和區(qū)時，向中和區(qū)注入石灰石漿液，如圖13、圖3-11和圖3-32所示;③第三個部位是，無論反應(yīng)罐有無區(qū)域劃分，都經(jīng)吸收塔循環(huán)泵入口管道將石灰石漿液加入吸收系統(tǒng)中，如圖1-3游線部分和圖3-9所示。這種方式實際上將循環(huán)泵入口至噴嘴之間的漿管和泵體部分視作為中和區(qū)，因此類似于第②種方式。AF泡沫泵

Performance comparison of two forced oxidation devices for AF foam pump

(1) The particle size of FAS atomized air bubbles is larger than that of ALS. The mass transfer efficiency of FAS depends largely on the immersion depth, followed by the air flow rate per unit volume of oxidation zone. If the liquid level of the tank is low, the immersion depth of the nozzle is low. To achieve the same oxidation effect, relatively more air must be inflated.

The minimum air flow rate of FAS is not less than 30%~40% of the maximum air flow rate. And as long as there is slurry in the tank, the oxidation blower can not stop operation, otherwise the nozzle is prone to blockage. There are many mechanical components in FAS, and they are all in the tank body. The possibility of blockage is great and the maintenance work is obvious. Therefore, cautious selection should be made.

(2) The bubbles produced by ALS are finer and less dependent on depth. In order to ensure the mass transfer performance of ALS, the flow rate of oxidized air and the dispersion performance of agitator should be matched. If the flow rate of oxidized air is too large and exceeds the liquid flow dispersion ability, a large number of bubbles will be emitted. In severe cases, the suction side of the agitator blade will also collect a large number of bubbles, which will reduce the flow rate of the blade.

(3) Because the caliber of ALS nozzle is much larger than that of FAS, the flow rate of oxidized air can be greatly reduced without worrying about blockage of nozzle, so it is possible to operate in parallel with several blowers with smaller capacity.

5. Characteristic of Advanced Oxygen Air Distribution

(1) high oxidation performance; (2) low consumption of oxidized air; (3) uniform distribution of oxidized air; (4) easy maintenance.

Classification and composition of agitators

The agitator is a mixing equipment used to mix slurry and prevent slurry from settling. The purpose of stirring in slurry tank of absorption tower is not only solid particles in suspension slurry, but also the following functions: (1) to make the newly added absorbent slurry distribute evenly as soon as possible (if the absorbent slurry is directly added into the tank), to accelerate the dissolution of limestone; (2) to avoid the excessive concentration of local desulfurization reaction products, to prevent the formation of gypsum scale; (3) to improve the oxidation effect and the formation of ultra-native gypsum crystals. 。 Desulfurization mixer can be divided into Side-Feed batch mixer and jacking mixer according to the installation position. Both mixers are composed of shaft, blade, mechanical seal, gearbox, motor and so on. The jacking type mixing should be installed on the top of slurry tank and pit, and the mixing type mixer is used in most tank pools (such as limestone slurry tank, filter water pit, etc.) in the bowl removal system. The mixer in the slurry pool of the absorption tower can be jacked or side-feed, which mainly depends on the structure of the absorption tower and the slurry pool of the absorption tower. The lateral agitator is installed on the outer wall of the tank, as shown in Fig. 3-30 and Fig. 3-31.

1. Factors Considered in Mixer Design

The factors considered in the agitator design are to ensure the mixing effect, oxidation effect, low energy consumption, material selection and sealing.

2. Structural materials

Shell: Cast iron shell and top are connected to drive by flange, bottom is fixed on stirrer support by bolt. The bolt material is carbon steel coated with 1.4529 stainless steel.

Shaft Seal: Non-flushing one-way mechanical seal system, with mechanical seal shut-off device.

3. Pulse agitation system

The German Lurgi company is used in the mixing tank of the absorber tank and the accident slurry tank. The pulsing suspension pump and the pulse suspension device are used to extract the slurry from the slurry tank by the pulse slurry pump. After pressurizing, the suspension pipe is sprayed to the bottom of the slurry tank in the slurry tank to pressurize the slurry, and its principle diagram can be seen in figure 3-32. The function of the pool separator is to prevent mixing between the upper oxidation zone and the lower reaction pool. There are no mechanical rotating parts in the mixing device, and there is no need to stop and discharge slurry when the propeller fails. In addition, as long as there is slurry in the slurry tank, the propeller agitator can not be stopped for a long time (usually not more than 4h). But with the pulse suspension device, the slurry that has been deposited can be stirred up again after 10 minutes of restarting the mixing pump within 7 days of shutdown of FGD system, so the power consumption of FGD standby can be reduced. The disadvantage is that the cost is higher than that of propeller agitator.

3. The place where the limestone slurry is injected into the absorption tower

Usually, there are three places in the absorption tower where limestone slurry can be injected: when the reaction tank is not clearly divided into oxidation zone and neutralization zone, limestone slurry is directly injected into the tank, as shown in JBR reactor as shown in Figure 3-10; when the reaction tank is divided into oxidation zone and neutralization zone, limestone slurry is injected into the neutralization zone as shown in Figure 13, Figure 3-11 and Figure 3-32; and thirdly, limestone slurry is injected into the tank. Whether or not the reaction tank is divided into zones, the limestone slurry is added to the absorption system through the inlet pipeline of the absorption tower circulating pump, as shown in Fig 1-3 and line 3-9. In this way, the slurry pipe and the pump part between the circulation pump inlet and the nozzle are actually regarded as the neutral zone, so it is similar to the second way. AF foam pump