Application of PE pipe microporous filter in salt slag and alkaline mud filtration

??? PE pipe microporous filter is first applied to insoluble materials and other impurities in sewage treatment in sewage treatment. With the continuous improvement of technology, such filters have been widely used in other industries because of their clear filtrate, low insoluble content, non-toxicity, and harmlessness, which have attracted widespread attention. The structure of this filter is shown in Figure 1. It is mainly composed of filter tube, filter box, liquid outlet tube and body. The filter element is PE filter tube. Weifu company filter tube is made of high-molecular material and formed during sintering. Micropores, which control the sintering temperature to obtain filter tubes with different pore sizes, suitable for filtering different media. The filtration principle is that the particles of salt residue, sludge or other organic impurities adhere to the outer wall of the tube, and the liquid penetrates into the tube through the micropores on the filter tube, and collects through the filter box and overflows. The filter cake attached to the outside of the tube is supplied with compressed air from the back-blowing valve, and is instantaneously blown back to slag, and then washed by washing water, and the washing water is discharged to the washing mud bucket in time. If the caustic soda salt is filtered, the washing water storage tank is circulated and concentrated, and then re-evaporated.

??? The process is as follows: The filtrate first enters the filtrate storage tank, and then is pumped into the PE pipe microporous filter by the mud pump, and is operated according to the initial low pressure, forming a filter cake, gradually pressurizing, and discharging the slag. The initial pressure is controlled below 0. 03M Pa. When the slag in the filtrate forms a filter cake on the outer wall of the filter tube, the particles in the suspension will rapidly “bridge” outside the microchannel under the pressure of the pump. Phenomenon, thus, a part of the fine particles having a diameter smaller than that of the micropores can also be intercepted, and the filtrate penetrates the filter cake into the filter cartridge, and flows out from the outlet pipe to the storage tank by the pumping process.

???? With the formation of the filter cake, the pressure operation is gradually carried out, but the pressure should not exceed 0. 2M Pa, according to the filter pressure and the discharge condition to determine the slagging time, if the pressure rises, the liquid output decreases, start When the slag is drained, the slagging valve is opened, the remaining valve is closed, the remaining valve is closed, the slurry is retracted, and then the slag discharge valve and the back blast valve are opened, and 0. 5M Pa compressed air is passed through the backflushing valve for instantaneous reversal Blow off the slag, then add water to wash. The washed water and the discharged filter residue are sent to each process or discharged according to different conditions. The flow diagram is shown in Figure 2.
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The filter tubes of the PE tube microporous filter are divided into several groups, and the filtration condition can be observed separately. If one of the filtrates is found to be unqualified, the filter tube can be closed.

??? After the PE pipe is used to a certain extent (such as caustic soda for about 7 to 8 months, soda mud for about 4 to 5 months), the filtration rate becomes slower, and some micropores are blocked, and regeneration treatment is required. The regeneration treatment is soaked and washed with a certain concentration of hydrochloric acid. The performance of the filter tube after regeneration is the same as the new tube.

??? 2 production applications

??? 2.1 Caustic soda salt filtration

??? A plant uses caustic soda as a raw material and caustic soda to produce caustic soda. The quality of the raw material trona varies greatly, the total alkali content is 15-30% (wt), and the salt nitrate content is 1-10% (wt). Especially when the salt content is high, it is difficult to complete the salting out by the heat-deficient salt of the evaporation process. Also rely on cold folding filter to complete after Zui. The cold-dissolved caustic soda solution is filtered through a microporous filter of Weifu Company PE tube, and the fine crystal nucleus which is not easy to settle in the clear liquid is filtered out, thereby further improving the quality of the salting out completion liquid and ensuring the purity of the caustic soda. The quality of the filtered material is shown in Table 1. Of course, there are similar problems with the diaphragm caustic soda. After clarification by cold analysis, a PE pipe filtration can also improve the quality of the filtrate.

???? 1 Filtration principle and process

??? PE pipe microporous filter is first applied to insoluble materials and other impurities in sewage treatment in sewage treatment. With the continuous improvement of technology, such filters have been widely used in other industries because of their clear filtrate, low insoluble content, non-toxicity, and harmlessness, which have attracted widespread attention. The structure of this filter is shown in Figure 1. It is mainly composed of filter tube, filter box, liquid outlet tube and body. The filter element is PE filter tube. The filter tube of Shanghai Weifu Filter Equipment Co., Ltd. is made of high-molecular material. Micropores are formed during sintering, and the sintering temperature can be controlled to obtain filter tubes with different pore sizes, which are suitable for filtering different media. The filtration principle is that the particles of salt residue, sludge or other organic impurities adhere to the outer wall of the tube, and the liquid penetrates into the tube through the micropores on the filter tube, and collects through the filter box and overflows. The filter cake attached to the outside of the tube is supplied with compressed air from the back-blowing valve, and is instantaneously blown back to slag, and then washed by washing water, and the washing water is discharged to the washing mud bucket in time. If the caustic soda salt is filtered, the washing water storage tank is circulated and concentrated, and then re-evaporated.

??? The process is as follows: The filtrate first enters the filtrate storage tank, and then is pumped into the PE pipe microporous filter by the mud pump, and is operated according to the initial low pressure, forming a filter cake, gradually pressurizing, and discharging the slag. The initial pressure is controlled below 0. 03M Pa. When the slag in the filtrate forms a filter cake on the outer wall of the filter tube, the particles in the suspension will rapidly “bridge” outside the microchannel under the pressure of the pump. Phenomenon, thus, a part of the fine particles having a diameter smaller than that of the micropores can also be intercepted, and the filtrate penetrates the filter cake into the filter cartridge, and flows out from the outlet pipe to the storage tank by the pumping process.

???? With the formation of the filter cake, the pressure operation is gradually carried out, but the pressure should not exceed 0. 2M Pa, according to the filter pressure and the discharge condition to determine the slagging time, if the pressure rises, the liquid output decreases, start When the slag is drained, the slagging valve is opened, the remaining valve is closed, the remaining valve is closed, the slurry is retracted, and then the slag discharge valve and the back blast valve are opened, and 0. 5M Pa compressed air is passed through the backflushing valve for instantaneous reversal Blow off the slag, then add water to wash. The washed water and the discharged filter residue are sent to each process or discharged according to different conditions. The flow diagram is shown in Figure 2.
?

The filter tubes of the PE tube microporous filter are divided into several groups, and the filtration condition can be observed separately. If one of the filtrates is found to be unqualified, the filter tube can be closed.

??? After the PE pipe is used to a certain extent (such as caustic soda for about 7 to 8 months, soda mud for about 4 to 5 months), the filtration rate becomes slower, and some micropores are blocked, and regeneration treatment is required. The regeneration treatment is soaked and washed with a certain concentration of hydrochloric acid. The performance of the filter tube after regeneration is the same as the new tube.

??? 2 production applications

??? 2.1 Caustic soda salt filtration

??? A plant uses caustic soda as a raw material and caustic soda to produce caustic soda. The quality of the raw material trona varies greatly, the total alkali content is 15-30% (wt), and the salt nitrate content is 1-10% (wt). Especially when the salt content is high, it is difficult to complete the salting out by the heat-deficient salt of the evaporation process. Also rely on cold folding filter to complete after Zui. The cold-dissolved caustic soda solution is filtered through a microporous filter of Weifu Company PE tube, and the fine crystal nucleus which is not easy to settle in the clear liquid is filtered out, thereby further improving the quality of the salting out completion liquid and ensuring the purity of the caustic soda. The quality of the filtered material is shown in Table 1. Of course, there are similar problems with the diaphragm caustic soda. After clarification by cold analysis, a PE pipe filtration can also improve the quality of the filtrate.

??? 2.2 Alkaline mud and clear liquid filtration

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??? With trona as raw material, no matter what kind of product is processed, it must first pass the lye refining process such as melting and clarification of trona. Due to the long-term intrusion of wind and sand or runoff from the surface of the mine, it is necessary to bring in a large amount of water insoluble matter and organic matter. Although the turbidity is mostly about 90ppm after clarification, it can be reduced to 50ppm after filtering by mechanical filter. However, the mechanical filter equipment chooses a fine filter cloth, and the filtration speed is slow. In a short time, the fine mud blocks the filtration. The cloth hole not only causes the waste of the lye, but also the filter mud sticks between the filter cloths and rinses with a large amount of water, which shortens the effective working time. After using the PE tube microporous filter of Shanghai Weifu Filtration Equipment Co., Ltd., the turbidity of the lye was reduced to 20 ppm, and the color of the lye changed from the original pale yellow to clear and transparent, which improved the quality of the product. See Table 2 for the comparison of the clear liquid and the alkaline mud before and after filtration.

??? 2.3 Filtering capacity

The measured data of different media filtered by three filter areas F=104M and one F=98. 8M 2 PE pipe filter are shown in Table 3.

As can be seen from the above table, the viscosity of the material and the high suspended matter are smaller.

??? 2.4 supporting equipment

??? PE pipe microporous filter equipment is relatively simple, if there is an air compressor station in the factory, you only need mud pump, feed pump and storage tank.

??? 3 Conclusion

??? 3.1 The device is novel in design. After being put into production, it is stable in operation and simple in operation. It has achieved good results in the alkali processing industry.

??? 3.2 The device has a short process and a small footprint. The filtering effect solves the problem of difficult solution refining in the alkali processing industry and opens up a new technical approach.

??? 3.3 The safety of this device can be used for solution refining and “three wastes” treatment and recycling in other industries.

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Article link: China Pharmaceutical Machinery Equipment Network