，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