A desulfurized gypsum grading and cleaning device and cleaning method

Abstract

The present invention relates to the field of desulfurized gypsum cleaning equipment, in particular to a desulfurized gypsum grading and cleaning device and a cleaning method. The desulfurized gypsum grading and cleaning device includes a spray head, a cleaning machine and a plurality of concentration devices. The cleaning machine and the plurality of concentration devices are arranged in sequence, and the gypsum slurry to be treated passes through the cleaning machine and the plurality of concentration devices in sequence; the cleaning machine and at least part of the concentration devices are provided with spray heads. By providing spray heads on the cleaning machine and at least part of the concentration devices, multiple flushes of the gypsum slurry can be achieved, effectively reducing the chloride ion and impurity content.

Description

Technical Field

[0001] The present invention relates to the field of desulfurized gypsum cleaning equipment, and particularly to a desulfurized gypsum grading and cleaning device and a cleaning method. Background Art

[0002] Most coal-fired power plants use the wet desulfurization process (about 90%) for flue gas desulfurization. The limestone-gypsum method is the main technical means, and its desulfurization by-product is desulfurized gypsum, that is, calcium sulfate dihydrate (CaSO4·2H2O), which can be widely used as raw materials in the preparation of building material products such as gypsum boards, gypsum blocks, and gypsum powders. However, there is no mature process and complete set of equipment in the gypsum production link, the process parameters are not specific, and the supporting equipment is not perfect, resulting in uneven quality of desulfurized gypsum. The desulfurized gypsum directly produced by power plants is difficult to meet the quality requirements of raw materials in the building materials field "National Standard for Flue Gas Desulfurized Gypsum". A large amount of desulfurized gypsum can only be treated as solid waste, causing great waste of resources. The main impurities in desulfurized gypsum include soluble salts (Cl-, F-), calcium carbonate, calcium sulfite, and trace heavy metals, etc. Among them, too high chloride ion content is the main reason for the poor quality of desulfurized gypsum. In addition, the moisture content is also an important index of desulfurized gypsum products. It is urgent to solve the problem of cleaning and removing impurities from desulfurized gypsum to form a set of devices or systems.

[0003] For example, application number CN201711443367.0 provides a method for washing high-chloride desulfurized gypsum. The high-chloride gypsum is washed through a vacuum belt dewatering system. The chloride ion content in the source gypsum slurry is increased from the normal concentration of 20,000 PPm to 50,000 PPm. To ensure the normal operation of the belt dewatering machine and the quality of gypsum, the filter cake washing water is recycled.

[0004] The above-mentioned gypsum washing method has the following problems:

[0005] 1. Only one-time flushing is carried out, and the chloride ion and impurity contents cannot be effectively reduced.

[0006] 2. The washed filter cake is dewatered by a vacuum belt machine, and only the chloride ions on the surface of the filter cake can be washed, and the chloride ions inside the filter cake cannot be washed.

[0007] 3. The flushing time is short, and the soluble impurities cannot be fully dissolved.

[0008] 4. The flushing water consumption is large, resulting in a large increase in high-salt wastewater, which increases the difficulty of subsequent high-salt wastewater treatment. Summary of the Invention

[0009] The present invention provides a desulfurized gypsum grading and cleaning device and a cleaning method, which solve the problem that the existing method cannot effectively reduce the chloride ion and impurity contents.

[0010] The technical solution of the present invention is realized as follows:

[0011] A desulfurized gypsum grading and cleaning device is provided, which includes a spray head, a cleaning machine and a plurality of concentration devices. The cleaning machine and the plurality of concentration devices are arranged in sequence, and the gypsum slurry to be treated passes through the cleaning machine and the plurality of concentration devices in sequence;

[0012] The cleaning machine and at least part of the concentration devices are provided with spray heads.

[0013] Preferably, the cleaning machine is an ultrasonic cleaning machine;

[0014] A spray head is arranged on the upper part of the ultrasonic cleaning machine.

[0015] Preferably, the desulfurized gypsum grading and cleaning device includes three concentration devices;

[0016] The three concentration devices are respectively a gypsum hydrocyclone, a disk dewaterer and a vacuum belt filter;

[0017] The gypsum hydrocyclone, the disk dewaterer and the vacuum belt filter are arranged in sequence, and spray heads for flushing the gypsum slurry inside are arranged on both the gypsum hydrocyclone and the disk dewaterer.

[0018] Preferably, it further includes a water inlet pipe. The spray heads are all communicated with the water inlet pipe, and a regulating valve for adjusting the water spray amount is arranged on each spray head.

[0019] Preferably, it further includes a recovery water bucket;

[0020] Drain pipes are arranged at the bottoms of the ultrasonic cleaning machine, the gypsum hydrocyclone and the disk dewaterer, and the drain pipes are communicated with the recovery water bucket.

[0021] Preferably, a discharge pump is arranged at the feeding end of the ultrasonic flushing machine, and the discharging end of the disk dewaterer is connected to the feeding end of the vacuum belt filter.

[0022] A desulfurized gypsum grading and cleaning method includes cleaning and multiple concentration treatments of the gypsum slurry;

[0023] During the cleaning process and part of the concentration process of the gypsum slurry, the gypsum slurry is flushed.

[0024] Preferably, during the first several concentration processes of the gypsum slurry, the gypsum slurry is flushed.

[0025] Preferably, the gypsum slurry undergoes three concentration processes, and the gypsum slurry is flushed during the first two concentration processes of the gypsum slurry.

[0026] Preferably, the gypsum slurry is flushed by means of spraying.

[0027] In the technical solution of the present invention, spray heads are provided on the cleaning machine and at least part of the concentration device, which can realize multiple flushes of the gypsum slurry and effectively reduce the chloride ion and impurity contents. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 FIG. is a schematic structural diagram of a desulfurized gypsum grading and cleaning device provided for the specific embodiment of the present invention.

[0030] 1: Spray head; 2: Ultrasonic cleaning machine; 3: Gypsum cyclone; 4: Disc dewatering machine; 5: Vacuum belt filter; 6: Water inlet pipe; 7: Recovery water bucket; 8: Drain pipe; 9: Discharge pump. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0032] As Figure 1 shown, a desulfurized gypsum grading and cleaning device is provided, which includes a spray head 1, a cleaning machine and a plurality of concentration devices. The cleaning machine and the plurality of concentration devices are arranged in sequence, and the gypsum slurry to be treated passes through the cleaning machine and the plurality of concentration devices in sequence. Spray heads 1 are provided on the cleaning machine and at least part of the concentration devices.

[0033] In this embodiment, spray heads 1 are provided on the cleaning machine and at least part of the concentration devices, which can realize multiple flushes of the gypsum slurry and effectively reduce the chloride ion and impurity contents.

[0034] The cleaning machine is an ultrasonic cleaning machine 2, and a spray head 1 is provided on the upper part of the ultrasonic cleaning machine 2.

[0035] The desulfurized gypsum grading and cleaning device includes three concentration devices, which are a gypsum cyclone 3, a disc dewatering machine 4 and a vacuum belt filter 5 respectively.

[0036] The gypsum hydrocyclone 3, the disc dewatering machine 4 and the vacuum belt filter 5 are arranged in sequence, and spray heads 1 for flushing the gypsum slurry inside thereof are arranged on both the gypsum hydrocyclone 3 and the disc dewatering machine 4.

[0037] The desulfurized gypsum grading flushing device further includes a water inlet pipe 6. The spray heads 1 are all communicated with the water inlet pipe 6, and a regulating valve for adjusting the water spraying amount is arranged on each spray head 1. The water spraying amount of each spray head 1 can be controlled through the regulating valve.

[0038] The desulfurized gypsum grading flushing device further includes a recovery water bucket 7, and the recovery water bucket 7 is used for the recovery of the spray wastewater.

[0039] Drain pipes 8 are arranged at the bottoms of the ultrasonic cleaning machine 2, the gypsum hydrocyclone 3 and the disc dewatering machine 4, and the drain pipes 8 are communicated with the recovery water bucket 7.

[0040] A discharge pump 9 is arranged at the feed end of the ultrasonic flushing machine 2, and the discharge end of the disc dewatering machine 4 is connected with the feed end of the vacuum belt filter 5.

[0041] In this embodiment, a desulfurized gypsum grading cleaning method is further provided, which performs cleaning and multiple concentration treatments on the gypsum slurry, and flushes the gypsum slurry during the cleaning process and part of the concentration process of the gypsum slurry.

[0042] The gypsum slurry is flushed during the first several concentration processes of the gypsum slurry. Specifically, the gypsum slurry undergoes three concentration processes, and the gypsum slurry is flushed during the first two concentration processes of the gypsum slurry. The gypsum slurry is flushed by means of spraying. After the last concentration, spraying is carried out again. The spraying water cannot enter the inside of the filter cake, that is, the effect of removing chloride ions by spraying in this step is poor. For the consideration of water conservation, spraying is not carried out in the last step.

[0043] In order to implement the above cleaning device and cleaning method, this embodiment further provides a treatment process of the gypsum slurry: Limestone with small particle size and high purity obtained by a ball mill is made into limestone slurry, which is sent to the upper part of the absorption tower through a slurry circulation pump to form a spray layer. An oxidation blower provides necessary air volume for washing, circulating, absorbing, oxidizing, crystallizing and other reactions of the sulfur-containing flue gas. The solids in the slurry are continuously separated and discharged through a gypsum discharge pump. Subsequently, the gypsum slurry enters the grading flushing and desalting system and the grading dewatering system.

[0044] The gypsum slurry enters the ultrasonic cleaning machine box through the discharge pump 9. After the first-stage flushing, a slurry with about 8%-15% solids is obtained. After passing through the first-stage cyclone concentration device, the second-stage flushing is carried out simultaneously to obtain a gypsum slurry with 40%-50% solids. Then it is sent to the disc dewatering machine and the third-stage flushing is carried out simultaneously. After entering the vacuum belt filter for the third-stage dewatering, wet gypsum with a moisture content of less than 10% is obtained. Specifically, it is as described below:

[0045] 1: Performing three-stage rinsing can efficiently and significantly reduce the chloride ion content.

[0046] 2: When performing the first-stage rinsing on the gypsum slurry, an ultrasonic cleaner is used for oscillation to clean the soluble salts contained in the turbidity inside the slurry.

[0047] 3: When performing the first-stage rinsing on the gypsum slurry, ultrasonic oscillation is used to accelerate the dissolution rate of chloride ions and achieve the purpose of rapid cleaning.

[0048] 4: When performing the first-stage rinsing on the gypsum slurry, ultrasonic oscillation is used to fully dissolve the soluble salts and achieve the purpose of rapid cleaning.

[0049] 5: When performing the first-stage rinsing on the gypsum slurry, when the density of the gypsum slurry is too high (> 1200 kg / m3), a spray head is used to supplement a small amount of water, which can greatly reduce the water consumption.

[0050] 6: When performing the first-stage dehydration on the gypsum slurry, after passing through the first-stage hydrocyclone concentrator, a gypsum slurry with 40%-50% solids is obtained.

[0051] 7: Performing the second-stage rinsing on the gypsum slurry with 40%-50% solids can further reduce the chloride ion and other impurity contents in the desulfurized gypsum.

[0052] 8: When performing the second-stage and third-stage rinsing on the gypsum slurry, a spray head is also used to reduce the water consumption.

[0053] 9: After performing the second-stage rinsing on the gypsum slurry with 40%-50% solids, it enters a disk dewatering machine for second-stage dehydration.

[0054] 10: Performing the third-stage rinsing on the gypsum filter cake after second-stage dehydration.

[0055] 11: The desulfurized gypsum filter cake after the third-stage rinsing then enters a vacuum belt filter for third-stage dehydration to obtain wet gypsum with a moisture content of less than 10%.

[0056] 12: The wastewater after the staged rinsing is discharged to a recovery water tank.

[0057] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A desulfurized gypsum classification and cleaning device, characterized in that, it includes a spray head, a cleaning machine and multiple concentration devices. The cleaning machine and multiple concentration devices are arranged in sequence, and the gypsum slurry to be treated passes through the cleaning machine and multiple concentration devices in sequence; spray heads are arranged on the cleaning machine and at least part of the concentration devices; the cleaning machine is an ultrasonic cleaning machine; a spray head is arranged on the upper part of the ultrasonic cleaning machine; the desulfurized gypsum classification and cleaning device includes three concentration devices; the three concentration devices are respectively a gypsum hydrocyclone, a disc dewaterer and a vacuum belt filter; the gypsum hydrocyclone, the disc dewaterer and the vacuum belt filter are arranged in sequence, and spray heads for flushing the gypsum slurry inside are arranged on both the gypsum hydrocyclone and the disc dewaterer; it further includes a water inlet pipe. The spray heads are all communicated with the water inlet pipe, and a water flow regulating valve is arranged on each spray head; it further includes a recovery water bucket; drain pipes are arranged at the bottoms of the ultrasonic cleaning machine, the gypsum hydrocyclone and the disc dewaterer, and the drain pipes are communicated with the recovery water bucket.

2. The desulfurized gypsum classification and cleaning device according to claim 1, characterized in that, a discharge pump is arranged at the feed end of the ultrasonic cleaning machine, and the discharge end of the disc dewaterer is connected to the feed end of the vacuum belt filter.

3. A desulfurized gypsum classification and cleaning method based on the desulfurized gypsum classification and cleaning device according to claim 1 or 2, characterized in that, the gypsum slurry is cleaned and concentrated multiple times; the gypsum slurry is flushed during the cleaning process and part of the concentration process of the gypsum slurry.

4. The desulfurized gypsum classification and cleaning method according to claim 3, characterized in that, the gypsum slurry is flushed during the first few concentration processes of the gypsum slurry.

5. The desulfurized gypsum classification and cleaning method according to claim 4, characterized in that, the gypsum slurry undergoes three concentration processes, and the gypsum slurry is flushed during the first two concentration processes of the gypsum slurry.

6. The desulfurized gypsum classification and cleaning method according to claim 3, characterized in that, the gypsum slurry is flushed by means of spraying.

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