A system and method for recycling calcium-containing sludge from power plant water purification

Abstract

The present invention provides a system and method for recycling calcium-containing sludge from power plant water purification. The system for recycling calcium-containing sludge from power plant water purification includes a sludge concentration tank, a desulfurizer grinding unit and a desulfurizer slurry supply unit; the sludge concentration tank is used to store calcium-containing sludge from the power plant clarification tank, and the calcium-containing sludge is sent to the desulfurizer grinding unit or the desulfurizer slurry supply unit; the desulfurizer grinding unit is used to circulate and grind limestone and calcium-containing sludge mixed materials; the desulfurizer slurry supply unit is used to store calcium-containing sludge or mixed slurry from the sludge concentration tank and the desulfurizer grinding unit and send the calcium-containing sludge or mixed slurry to the desulfurization system for use as a desulfurizer. Compared with the prior art, the present invention realizes the treatment and reuse of calcium-containing sludge by conveying calcium-containing sludge to the desulfurization system for use as a desulfurizer, reduces the cost of polyacrylamide chemicals and sludge transportation and treatment when dehydrating calcium-containing sludge, and reduces the cost of alkaline limestone consumption of desulfurizer in the desulfurization system.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste recycling, and in particular to a system and method for recycling calcium-containing sludge for water purification in power plants. Background Art

[0002] With the development of the national economy, energy conservation and environmental protection have become increasingly important factors affecting the survival and development of enterprises. As an important solid waste, the sludge from the water purification system of coal-fired power plants is currently mainly treated by dehydrating and drying the sludge, forming dry mud cakes and then transporting them outside the plant. However, this method has the following problems: poor operating environment of the sludge treatment system, difficulty in operating and maintaining the sludge dewatering machine, high consumption of chemicals, limited sludge transportation, and high disposal costs. These problems have become increasingly prominent, and to a certain extent, have also increased the environmental risks in the operation of power plants. Therefore, how to make rational use of the sludge from the water purification system has become an urgent task.

[0003] Since the sludge from the water purification system contains a large amount of limestone CaCO3, with a relative content of up to 76.569%, and the limestone wet desulfurization method is a common process for flue gas desulfurization in power plants, its desulfurizer is consistent with the sludge composition. Therefore, transporting the sludge from the water purification system in coal-fired power plants to the desulfurization system as a desulfurizer is of great significance to reducing the cost of sludge disposal and desulfurizer costs and achieving "zero" solid waste emissions. To a certain extent, it can provide an effective reference for the disposal of sludge in power plants. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a system for recycling power plant water quality to purify calcium-containing sludge, which can effectively reduce the cost of sludge disposal.

[0005] The present invention provides a system for recycling power plant water quality to purify calcium-containing sludge, comprising a sludge concentration tank, a desulfurization agent grinding unit and a desulfurization agent slurry supply unit;

[0006] The sludge concentration tank is used to store calcium-containing sludge from the clarification tank of the power plant, and the outlet of the sludge concentration tank is connected to the desulfurization agent grinding unit and the desulfurization agent slurry supply unit through pipelines respectively;

[0007] The desulfurizing agent grinding unit comprises a mill recycling box, a cyclone separation mechanism and a limestone wet ball mill; wherein the inlet of the mill recycling box is connected to the outlet of the sludge thickening tank and the outlet of the limestone wet ball mill through pipelines, respectively, and the outlet of the mill recycling box is connected to the inlet of the cyclone separation mechanism through a pipeline; the cyclone separation mechanism comprises a cyclone separator, the top outlet of the cyclone separator is connected to the inlet of the desulfurizing agent slurry supply unit through a pipeline, and the bottom outlet of the cyclone separator is connected to the inlet of the limestone wet ball mill through a pipeline;

[0008] The desulfurizer slurry supply unit is used to store calcium-containing sludge from the sludge concentration tank and the desulfurizer grinding unit, and the outlet of the desulfurizer slurry supply unit is connected to the desulfurization system through a pipeline.

[0009] Preferably, the cyclone separation mechanism further comprises a cyclone feed box, the inlet of the cyclone feed box is connected to the outlet of the mill recirculation box through a pipeline, and the outlet of the cyclone feed box is connected to the inlet of the cyclone separator through a pipeline.

[0010] Preferably, a plurality of cyclone separators are provided, and the plurality of cyclone separators are connected in parallel.

[0011] Preferably, the desulfurizer grinding unit also includes an underflow collecting box and an overflow collecting box, the inlet of the underflow collecting box is connected to the bottom outlet of the cyclone separator through a pipeline, and the outlet of the underflow collecting box is connected to the inlet of the limestone wet ball mill through a pipeline; the inlet of the overflow collecting box is connected to the top outlet of the cyclone separator through a pipeline, and the outlet of the overflow collecting box is respectively connected to the inlet of the mill recycling box and the inlet of the desulfurizer slurry supply unit through pipelines.

[0012] Preferably, the desulfurizing agent grinding unit further comprises a limestone feeding device for providing limestone to the limestone wet ball mill, and a discharge port of the limestone feeding device is connected to an inlet of the limestone wet ball mill through a pipeline.

[0013] Preferably, a flushing component is provided at the outlet of the sludge thickening tank, and the flushing component is used for flushing the outlet pipe of the sludge thickening tank.

[0014] Preferably, the system further comprises a centrifugal dehydrator, the inlet of the centrifugal dehydrator is connected to the outlet of the sludge thickening tank through a pipeline.

[0015] The present invention also provides a method for recycling calcium-containing sludge used for water purification in a power plant, wherein the system as described above is used to measure the density of calcium-containing sludge in a sludge concentration tank, and if the density of the calcium-containing sludge is greater than a preset density, the calcium-containing sludge is transported to a desulfurizer slurry supply unit; if the density of the calcium-containing sludge is less than or equal to the preset density, the calcium-containing sludge is transported to the mill recirculation box to be mixed with limestone slurry ground by a limestone wet ball mill;

[0016] The calcium-containing sludge and limestone mixed slurry in the mill recirculation box is sent to the cyclone separator for separation; the calcium-containing sludge and limestone mixed slurry flowing out of the top outlet of the cyclone separator enters the desulfurizer slurry supply unit, and the calcium-containing sludge and limestone mixed slurry flowing out of the bottom outlet of the separator enters the limestone wet ball mill; the limestone and calcium-containing sludge mixed material ground in the limestone wet ball mill is sent to the mill recirculation box again to complete the cycle;

[0017] The mixed slurry of calcium-containing sludge and limestone in the desulfurizer slurry supply unit is sent to the desulfurization system for desulfurization.

[0018] Preferably, the desulfurization system includes an absorption tower, and the mixed slurry of calcium-containing sludge and limestone in the desulfurizer slurry supply unit is fed into the top of the absorption tower. The mixed slurry of calcium-containing sludge and limestone is sprayed from top to bottom in the absorption tower to form alkaline slurry droplets and countercurrently contacts with the flue gas entering the absorption tower. The slurry absorbs SO2 in the flue gas and reacts to generate CaSO3, which is oxidized and crystallized to generate CaSO4·2H2O, and gypsum is generated after dehydration to achieve desulfurization.

[0019] Preferably, when the desulfurization system cannot consume enough calcium-containing sludge, the calcium-containing sludge in the sludge thickening tank is transported to a centrifugal dehydrator for dehydration treatment, and the dehydrated sludge is aired and then sent to the boiler for co-combustion.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. By transporting calcium-containing sludge to the desulfurization system for use as a desulfurizer, the calcium-containing sludge can be treated and reused. On the one hand, the cost of polyacrylamide chemicals and sludge transportation and treatment during the dehydration of calcium-containing sludge is reduced, and on the other hand, the cost of alkaline limestone consumption as a desulfurizer in the desulfurization system is reduced, which is of great significance for solving the environmental risk problems in traditional sludge disposal;

[0022] 2. The present invention provides a first sludge delivery pump and a second sludge delivery pump in the water purification calcium-containing sludge delivery device, which can not only meet the demand of sludge delivery through the second sludge delivery pump when the sludge delivery pump is under maintenance, but also provide a centrifugal dehydrator connected to the second sludge delivery pump, so that when the desulfurization system cannot consume enough calcium-containing sludge, the calcium-containing sludge can be delivered to the centrifugal dehydrator for dehydration, drying, and mixed burning, thereby achieving "zero discharge" of calcium-containing sludge;

[0023] 3. The present invention sets a spare limestone slurry tank in the desulfurizer slurry supply unit, which can flexibly adjust the destination of the calcium-containing sludge according to the density of the calcium-containing sludge in the sludge thickening tank. When the density of the calcium-containing sludge is higher than the preset density, the calcium-containing sludge is directly transported to the spare limestone slurry tank for being sent to the absorption tower for use as a desulfurizer, thereby reducing the grinding cost and consumption of the calcium-containing sludge in the desulfurizer grinding device, and realizing efficient and economical operation of the system.

[0024] The above technical features can be combined in various suitable ways or replaced by equivalent technical features as long as the purpose of the present invention can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention will be described in more detail below based on non-limiting examples and with reference to the accompanying drawings, in which:

[0026] Figure 1 A schematic diagram of the structure of a system for recycling power plant water to purify calcium-containing sludge provided in one embodiment of the present invention;

[0027] Figure 2 This is a schematic structural diagram of a water purification calcium-containing sludge conveying unit in one embodiment of the present invention;

[0028] Figure 3 It is a schematic structural diagram of a desulfurizing agent grinding unit in one embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of a desulfurizer slurry supply unit in one embodiment of the present invention.

[0030] Description of reference numerals:

[0031] 1. Sludge thickening tank; 2. First sludge delivery pump; 3. Second sludge delivery pump; 4. Centrifugal dehydrator; 5. Mill recirculation box; 6. A recirculation pump; 7. B recirculation pump; 8. Cyclone feed box; 9. First cyclone separator; 10. Second cyclone separator; 11. Third cyclone separator; 12. Overflow collection box; 13. Underflow collection box; 14. Limestone feeding device; 15. Limestone wet ball mill; 16. Ball adding bucket; 17. Limestone slurry tank; 18. Spare limestone slurry tank; 19. Limestone slurry pump A; 20. Limestone slurry pump B; 21. Spare limestone slurry pump A; 22. Spare limestone slurry pump B; 23. Absorption tower; 24. First pneumatic ball valve; 25. Second pneumatic ball valve; 26. Third pneumatic ball valve; 27. Fourth pneumatic ball valve; 28. First manual ball valve; 29. ​​Second manual ball valve 30, the third manual ball valve; 31, the fourth manual ball valve; 32, the fifth manual ball valve; 33, the sixth manual ball valve; 34, the seventh manual ball valve; 35, the eighth manual ball valve; 36, the ninth manual ball valve; 37, the tenth manual ball valve; 38, the eleventh manual ball valve; 39, the first electric ball valve; 40, the second electric ball valve; 41, the third electric ball valve; 42, the fourth electric ball valve; 43, the fifth electric ball valve; 44, the sixth electric ball valve; 45, the seventh electric ball valve; 46, the eighth electric ball valve; 47, the first manual butterfly valve; 48, the second manual butterfly valve; 49, the third manual butterfly valve; 50, the fourth manual butterfly valve; 51, the fifth manual butterfly valve; 52, the sixth manual butterfly valve; 53, the seventh manual butterfly valve; 54, the eighth manual butterfly valve; 55, the ninth manual butterfly valve; 56, the tenth manual butterfly valve; 57, the eleventh manual butterfly valve. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below. Based on the specific implementation methods in the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] like Figure 1 As shown, the system for recycling calcium-containing sludge from power plant water purification provided by the present invention comprises a sludge thickening tank 1, a desulfurizer grinding unit and a desulfurizer slurry supply unit. The sludge thickening tank 1 is used to store calcium-containing sludge from the clarification tank of the power plant, the desulfurizer grinding unit is used to grind the limestone added therein into slurry and mix it with the calcium-containing sludge from the sludge thickening tank 1; the desulfurizer grinding unit is used to store calcium-containing sludge from the sludge thickening tank 1 and the desulfurizer grinding unit, and the outlet of the desulfurizer slurry supply unit is connected to the desulfurization system through a pipeline.

[0034] The sludge wastewater from the clarifier of the power plant and the drainage from the drug storage area flow into the sludge thickening tank 1 respectively; the outlet of the sludge thickening tank is connected to the desulfurizer grinding unit and the desulfurizer slurry supply unit through pipelines. The sludge thickening tank 1, the pipelines in and out of the sludge thickening tank 1, the valves and the delivery pumps constitute the water purification calcium sludge delivery unit.

[0035] Specifically, Figure 2 As shown, the sludge sewage discharged from the clarifier of the power plant and the drainage from the drug storage area flow into the sludge thickening tank 1 through the first pneumatic ball valve 24 and the first manual butterfly valve 47 respectively; the first manual ball valve 28 and the second pneumatic ball valve 25 are sequentially arranged on the outlet pipe of the sludge thickening tank 1, and two parallel conveying pipelines are connected to the downstream of the outlet pipe, one of which is sequentially arranged with the second manual ball valve 29, the first sludge conveying pump 2 and the third manual ball valve 30; the other conveying pipeline is sequentially arranged with the fourth manual ball valve 31, the second sludge conveying pump 3 and the fifth manual ball valve 32; the third pneumatic ball valve 26 is arranged on the connecting pipe between the third manual ball valve 30 and the fifth manual ball valve 32 and the desulfurizer grinding unit; the fourth pneumatic ball valve 27 is arranged on the pipe between the third manual ball valve 30 and the fifth manual ball valve 32 and the desulfurizer slurry supply unit. In order to prevent the pipeline from being blocked, a flushing component is arranged at the outlet of the sludge thickening tank 1, and the flushing component is used to flush the outlet pipe of the sludge thickening tank 1. Specifically, the flushing component is a second manual butterfly valve 48, the inlet of the second manual butterfly valve 48 is connected to the water supply system through a pipeline, and industrial water flows into the outlet pipeline of the sludge concentration tank 1 through the second manual butterfly valve 48 to flush the conveying pipeline of the water-purified calcium-containing sludge.

[0036] The desulfurizing agent grinding unit includes a mill recirculation box 5 , a cyclone separation mechanism and a limestone wet ball mill 15 .

[0037] like Figure 1 , Figure 3 As shown, the mill recirculation box 5 is used to store the calcium-containing sludge from the sludge thickening tank 1, and its inlet is connected to the outlet of the sludge thickening tank 1 and the outlet of the limestone wet ball mill 15 through pipelines, and the outlet of the mill recirculation box 5 is connected to the inlet of the cyclone separation mechanism through a pipeline; specifically, as shown in FIG. Figure 1 As shown, the outlet of the third manual ball valve 30 and the outlet of the fifth manual ball valve 32 are connected to the inlet of the mill recirculation box 5 through a common pipeline, and the common pipeline is provided with a third pneumatic ball valve 26. The outlet of the mill recirculation box 5 is connected to the inlet of the cyclone separation mechanism through two parallel pipelines, one of which is provided with an eighth manual ball valve 35, a first recirculation pump 6 and a ninth manual ball valve 36 in sequence, and the other pipeline is provided with a tenth manual ball valve 37, a second recirculation pump 7 and an eleventh manual ball valve 38 in sequence.

[0038] The cyclone separation mechanism includes a cyclone separator, a cyclone feed box 8, an underflow collection box 13 and an overflow collection box 12. The inlet of the cyclone feed box 8 is connected to the outlet of the mill recirculation box 5 through a pipeline, and the outlet of the cyclone feed box 8 is connected to the inlet of the cyclone separator through a pipeline. The cyclone separator can be provided with one or more, such as Figure 1 As shown, three cyclone separators are provided, namely, the first cyclone separator 9, the second cyclone separator 10 and the third cyclone separator 11. A third manual butterfly valve 49 is provided on the pipeline connecting the inlet of the first cyclone separator 9 and the outlet of the cyclone feed box 8, a fourth manual butterfly valve 50 is provided on the pipeline connecting the inlet of the second cyclone separator 10 and the outlet of the cyclone feed box 8, and a fifth manual butterfly valve 51 is provided on the pipeline connecting the inlet of the third cyclone separator 11 and the outlet of the cyclone feed box 8. The third manual butterfly valve 49, the fourth manual butterfly valve 50 and the fifth manual butterfly valve 51 are respectively used to adjust the flow rate of the calcium-containing sludge and limestone mixed slurry entering the corresponding cyclone separator. The top outlet of each cyclone separator is connected to the inlet of the overflow collection box 12 through a pipeline, and the outlet of the overflow collection box 12 is connected to the inlet of the mill recirculation box 5 and the inlet of the desulfurizer slurry supply unit through pipelines, and a sixth manual butterfly valve 52 is provided on the connecting pipeline between the overflow collection box 12 and the desulfurizer slurry supply unit, and a seventh manual butterfly valve 53 is provided on the connecting pipeline between the overflow collection box 12 and the mill recirculation box 5. The bottom outlet of each cyclone separator is connected to the inlet of the underflow collection box 13 through a pipeline, and the outlet of the underflow collection box 13 is connected to the inlet of the limestone wet ball mill 15 through a pipeline.

[0039] The limestone wet ball mill 15 is used to grind the limestone added therein and the mixed slurry of calcium-containing sludge and limestone from the cyclone separator. The limestone and calcium-containing sludge mixed material ground by the limestone wet ball mill 15 are sent to the mill recirculation box 5 again to complete the cycle to meet the desulfurization agent requirements. In order to facilitate the addition of limestone to the limestone wet ball mill 15, a limestone feeding device 14 is also provided in the system, and the discharge port of the limestone feeding device 14 is connected to the inlet of the limestone wet ball mill 15. The limestone feeding device 14 may include a limestone feeding hopper, a vibrating feeder, a bucket elevator, a limestone storage bin and a weighing feeder connected in sequence. A ball adding hopper 16 is also provided, and the discharge port of the ball adding hopper 16 is connected to the inlet of the limestone wet ball mill 15. Balls are added to the limestone wet ball mill 15 through the ball adding hopper 16 to meet the grinding requirements.

[0040] In order to flush the equipment and pipelines, the mill recirculation box 5 is connected to the water supply system through a pipeline, and an eighth manual butterfly valve 54 is provided on the pipeline; the limestone wet ball mill 15 is connected to the water supply system through a pipeline, and a ninth manual butterfly valve 55 is provided on the pipeline; industrial water flows into the mill recirculation box 5 and the limestone wet ball mill 15 through the eighth manual butterfly valve 54 and the ninth manual butterfly valve 55 respectively.

[0041] like Figure 1 , Figure 4 As shown, the desulfurizer slurry supply unit includes a limestone slurry tank 17 and a spare limestone slurry tank 18. The limestone slurry tank 17 is used to store the calcium-containing sludge and limestone mixed slurry from the overflow collection tank 12, and its inlet is connected to the outlet of the overflow collection tank 12 through a pipeline, and the sixth manual butterfly valve 52 is arranged on the pipeline; the outlet of the limestone slurry tank 17 is connected to the inlet of the absorption tower 23 in the desulfurization system through two parallel pipelines. The first electric butterfly valve 39, the first limestone slurry pump 19 and the second electric butterfly valve 40 are arranged in sequence on one of the pipelines; the third electric butterfly valve 41, the second limestone slurry pump 20 and the fourth electric butterfly valve 42 are arranged in sequence on the other pipeline. The limestone slurry tank 17 is connected to the water supply system through a pipeline, and the tenth manual butterfly valve 56 is arranged on the pipeline; industrial water flows into the limestone slurry tank 17 through the tenth manual butterfly valve 56 to adjust the density of the calcium-containing sludge and limestone mixed slurry in the limestone slurry tank 17.

[0042] The standby limestone slurry tank 18 is used to store the calcium-containing sludge from the sludge thickening tank 1. Specifically, the outlet of the third manual ball valve 30 and the outlet of the fifth manual ball valve 32 are connected to the inlet of the standby limestone slurry tank 18 through a common pipeline, and the fourth pneumatic ball valve 27 is arranged on the common pipeline. The outlet of the standby limestone slurry tank 18 is connected to the inlet of the absorption tower 23 in the desulfurization system through two parallel pipelines, one of which is sequentially provided with a fifth electric butterfly valve 43, a standby limestone slurry pump A 21 and a sixth electric butterfly valve 44, and the other pipeline is sequentially provided with a seventh electric butterfly valve 45, a standby limestone slurry pump B 22 and an eighth electric butterfly valve 46. The standby limestone slurry tank 18 is connected to the water supply system through a pipeline, and the pipeline is provided with an eleventh manual butterfly valve 57; industrial water flows into the standby limestone slurry tank 18 through the eleventh manual butterfly valve 57 to adjust the density of the calcium-containing sludge in the limestone slurry tank 18.

[0043] In one embodiment, the system for recycling and reusing power plant water to purify calcium-containing sludge further comprises a centrifugal dehydrator 4, the inlet of the centrifugal dehydrator 4 is connected to the outlet of the sludge thickening tank 1 through a pipeline. Figure 1 , Figure 2 As shown, the inlet of the centrifugal dehydrator 4 and the outlet of the second sludge delivery pump 3 are connected through a pipeline, and a sixth manual ball valve 33 is arranged on the pipeline.

[0044] In another embodiment, the inlet of the sludge thickening tank 1 and the outlet of the second sludge delivery pump 3 are connected by a pipeline, and a seventh manual ball valve 34 is arranged on the pipeline.

[0045] The system for recycling power plant water purification containing calcium sludge provided by the present invention can be used to recycle power plant water purification containing calcium sludge. The method for recycling power plant water purification containing calcium sludge provided by the present invention adopts the above-mentioned system for recycling power plant water purification containing calcium sludge, and comprises the following steps:

[0046] Determine the density of the calcium-containing sludge in the sludge thickening tank. If the density of the calcium-containing sludge is greater than the preset density, the calcium-containing sludge is transported to the desulfurizer slurry supply unit; if the density of the calcium-containing sludge is less than or equal to the preset density, the calcium-containing sludge is transported to the mill recirculation box;

[0047] In the mill recirculation box, the calcium-containing sludge is mixed with the limestone slurry ground by the limestone wet ball mill and sent to the cyclone separator for separation; the mixed slurry with qualified particle size flowing out of the top outlet of the cyclone separator enters the desulfurizer slurry supply unit, and the mixed slurry with unqualified particle size flowing out of the bottom outlet of the separator enters the limestone wet ball mill; the limestone and calcium-containing sludge mixture ground in the limestone wet ball mill is sent to the mill recirculation box again to complete the cycle;

[0048] The mixed slurry of calcium-containing sludge and limestone in the desulfurizer slurry supply unit is sent to the desulfurization system for desulfurization.

[0049] Next, combine Figure 1 The system for recycling and utilizing calcium-containing sludge from power plant water purification shown in the figure describes in detail the method for recycling and utilizing calcium-containing sludge from power plant water purification.

[0050] Step 1: After the calcium-containing sludge is naturally settled in the sludge thickening tank 1, the density of the calcium-containing sludge in the sludge thickening tank 1 is measured, and the measured density is compared with the preset density to determine whether the calcium-containing sludge is transported to the desulfurizer grinding unit or the desulfurizer slurry supply unit.

[0051] The calcium-containing sludge comes from the clarifier of the power plant water purification. The sewage from the sludge pump of the clarifier and the drainage from the drug storage area flow into the sludge concentration tank 1 through the first pneumatic ball valve 24 and the first manual butterfly valve 47 respectively, and flow out through the first manual ball valve 28 and the second pneumatic ball valve 25 after natural sedimentation in the sludge concentration tank 1, and then enter the desulfurizer grinding unit or the desulfurizer slurry supply unit after the first sludge delivery pump 2 or the second sludge delivery pump 3 boosts the pressure to provide power.

[0052] In the above steps, if the density of the calcium-containing sludge is higher than the preset density, it can be directly used in the spare limestone slurry tank 18 of the desulfurizer slurry supply unit, then the fourth pneumatic ball valve 27 is opened and the third pneumatic ball valve 26 is closed; if the density of the calcium-containing sludge is lower than or equal to the preset density, the calcium-containing sludge cannot be directly used in the desulfurizer slurry supply unit, then the third pneumatic ball valve 26 is opened and the fourth pneumatic ball valve 27 is closed, so that the calcium-containing sludge enters the desulfurizer grinding unit. In this embodiment, the preferred preset density is 1080kg / m 3 .

[0053] In the above steps, if the first sludge delivery pump 2 is running, the second manual ball valve 29 and the third manual ball valve 30 are opened, and the calcium-containing sludge is delivered to the desulfurizer grinding unit or the desulfurizer slurry supply unit through the first sludge delivery pump 2. At this time, the fourth manual ball valve 31 is closed, and the second sludge delivery pump 3 is in a standby state. If the sludge delivery pump 2 is in an overhaul or standby state, the fourth manual ball valve 31 and the fifth manual ball valve 32 are opened, the second manual ball valve 29 and the third manual ball valve 30 are closed, and the calcium-containing sludge is delivered to the desulfurizer grinding unit or the desulfurizer slurry supply unit through the second sludge delivery pump 3.

[0054] If the desulfurization system cannot completely consume all the calcium-containing sludge, a part of the calcium-containing sludge is sent to the centrifugal dewatering machine 4 and the sludge thickening tank 1 respectively through the second sludge delivery pump 3. The calcium-containing sludge entering the centrifugal dewatering machine 4 is mixed with polyacrylamide through the dosing device to achieve dehydration. The dehydrated sludge is dried and sent to the boiler for mixed combustion. At this time, the fourth manual ball valve 31, the sixth manual ball valve 33, and the seventh manual ball valve 34 are opened, and the fifth manual ball valve 32 is closed.

[0055] Furthermore, in order to prevent the pipeline from being blocked, industrial water flows into the outlet of the sludge concentration tank 1 through the second manual butterfly valve 48 to flush the pipeline of the water purification calcium-containing sludge conveying device.

[0056] Step 2: In the desulfurizer grinding unit, the mixed slurry of the calcium-containing sludge in the mill recirculation box 5 and the limestone ground by the limestone wet ball mill is sent to the cyclone feed box 8, and the mixed slurry entering the cyclone feed box 8 is respectively sent to the first cyclone separator 9, the second cyclone separator 10 and the third cyclone separator 11. After separation by the cyclone separator, the mixed slurry with qualified particle size overflows from the top outlet of the separator into the overflow collecting box 12. A part of the mixed slurry in the overflow collecting box 12 directly flows into the limestone slurry box 17 of the desulfurizer slurry supply unit for use as a desulfurizer, and the other part flows back into the mill recycling box 5 to complete the cycle; the unqualified mixed slurry flows out from the bottom of the separator into the underflow collecting box 13, and the mixed slurry in the underflow collecting box 13 is sent to the inlet of the limestone wet ball mill 15, and is ground in the limestone wet ball mill 15 together with the material from the limestone feeding device 14. The ball mill 15 can add balls through the ball adding bucket 16 to meet the grinding requirements. The limestone and calcium-containing sludge mixture ground in the limestone wet ball mill 15 is sent to the mill recycling box 5 again to complete the cycle to meet the desulfurizer requirements.

[0057] In the above steps, the calcium-containing sludge flowing out of the mill recirculation box 5 and the limestone mixed slurry after the limestone wet ball mill is ground can be sent to the cyclone feed box 8 through the first recirculation pump 6 or the second recirculation pump 7. If the first recirculation pump 6 is running, the second recirculation pump 7 is in a standby or overhaul state, at this time, the eighth manual ball valve 35 and the ninth manual ball valve 36 are opened, and the tenth manual ball valve 37 and the eleventh manual ball valve 38 are closed. If the second recirculation pump 7 is running, the first recirculation pump 6 is in a standby or overhaul state, at this time, the tenth manual ball valve 37 and the eleventh manual ball valve 38 are opened, and the eighth manual ball valve 35 and the ninth manual ball valve 36 are closed.

[0058] The mixed slurry entering the cyclone feed box 8 can enter the first cyclone separator 9, the second cyclone separator 10, and the third cyclone separator 11 through the third manual butterfly valve 49, the fourth manual butterfly valve 50, and the fifth manual butterfly valve 51 respectively.

[0059] A portion of the mixed slurry in the overflow collection box 12 flows directly into the limestone slurry tank 17 of the desulfurizer slurry supply device through the sixth manual butterfly valve 52 ; the other portion flows back into the mill recirculation tank 5 through the seventh manual butterfly valve 53 .

[0060] Furthermore, in order to flush the equipment and pipelines, industrial water flows into the mill recirculation box 5 and the limestone wet ball mill 15 through the eighth manual butterfly valve 54 and the ninth manual butterfly valve 55 respectively.

[0061] Step 3: The calcium-containing sludge and limestone mixed slurry in the desulfurizer slurry supply unit is sent to the top of the absorption tower 23 of the desulfurization system. The calcium-containing sludge and limestone mixed slurry is sprayed from top to bottom in the absorption tower 23 to form alkaline slurry droplets, which are countercurrently contacted with the flue gas entering the absorption tower 23. The slurry absorbs SO2 in the flue gas and reacts to generate CaSO3, which is oxidized and crystallized to generate CaSO4·2H2O, and gypsum is generated after dehydration to achieve desulfurization.

[0062] In the desulfurizer slurry supply unit, the standby limestone slurry tank 18 is used to store the calcium-containing sludge from the sludge thickening tank 1, and the limestone slurry tank 17 is used to store the calcium-containing sludge and limestone mixed slurry from the overflow collection tank 12. The mixed slurry in the limestone slurry tank 17 is sent to the absorption tower 23 through the first limestone slurry pump 19 or the second limestone slurry pump 20; if the first limestone slurry pump 19 is running, the second limestone slurry pump 20 is in a standby or overhaul state, at this time, the first electric ball valve 39 and the second electric ball valve 40 are opened, and the third electric ball valve 41 and the fourth electric ball valve 42 are closed; if the second limestone slurry pump 20 is running, the first limestone slurry pump 19 is in a standby or overhaul state, at this time, the third electric ball valve 41 and the fourth electric ball valve 42 are opened; the first electric ball valve 39 and the second electric ball valve 40 are closed. The calcium-containing sludge in the standby limestone slurry tank 18 is sent to the absorption tower 23 through the standby limestone slurry pump A 21 or the standby limestone slurry pump B 22; if the standby limestone slurry pump A 21 is running and the standby limestone slurry pump B 22 is in a standby or maintenance state, the fifth electric ball valve 43 and the sixth electric ball valve 44 are opened, and the seventh electric ball valve 45 and the eighth electric ball valve 46 are closed; if the standby limestone slurry pump B 22 is running and the standby limestone slurry pump A 21 is in a standby or maintenance state, the seventh electric ball valve 45 and the eighth electric ball valve 46 are opened, and the fifth electric ball valve 43 and the sixth electric ball valve 44 are closed.

[0063] Finally, it should be noted that the above implementation modes and examples are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above implementation modes and examples, those skilled in the art should understand that they can still modify the technical solutions described in the above implementation modes or examples, or replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the implementation modes or examples of the present invention.

Claims

1. A system for recycling calcium-containing sludge from power plant water purification, characterized in that: It includes a sludge thickening tank, a desulfurizer grinding unit and a desulfurizer slurry supply unit; The sludge thickening tank is used to store calcium-containing sludge from the clarification tank of the power plant, and the outlet of the sludge thickening tank is connected to the desulfurization agent grinding unit and the desulfurization agent slurry supply unit through pipelines respectively; The desulfurizing agent grinding unit comprises a mill recycling box, a cyclone separation mechanism and a limestone wet ball mill; wherein the inlet of the mill recycling box is connected to the outlet of the sludge thickening tank and the outlet of the limestone wet ball mill through pipelines, respectively, and the outlet of the mill recycling box is connected to the inlet of the cyclone separation mechanism through a pipeline; the cyclone separation mechanism comprises a cyclone separator, the top outlet of the cyclone separator is connected to the inlet of the desulfurizing agent slurry supply unit through a pipeline, and the bottom outlet of the cyclone separator is connected to the inlet of the limestone wet ball mill through a pipeline; The desulfurizer slurry supply unit is used to store calcium-containing sludge from the sludge concentration tank and the desulfurizer grinding unit, and the outlet of the desulfurizer slurry supply unit is connected to the desulfurization system through a pipeline; The desulfurizer grinding unit also includes an underflow collection box and an overflow collection box, the inlet of the underflow collection box is connected to the bottom outlet of the cyclone separator through a pipeline, and the outlet of the underflow collection box is connected to the inlet of the limestone wet ball mill through a pipeline; the inlet of the overflow collection box is connected to the top outlet of the cyclone separator through a pipeline, and the outlet of the overflow collection box is respectively connected to the inlet of the mill recirculation box and the inlet of the desulfurizer slurry supply unit through pipelines; The outlet pipe of the sludge thickening tank is provided with a first manual ball valve and a second pneumatic ball valve in sequence, and two parallel delivery pipelines are connected to the downstream of the outlet pipe, wherein the second manual ball valve, the first sludge delivery pump and the third manual ball valve are provided in sequence on one delivery pipeline, and the fourth manual ball valve, the second sludge delivery pump and the fifth manual ball valve are provided in sequence on the other delivery pipeline; The system further comprises a centrifugal dehydrator, the inlet of the centrifugal dehydrator is connected to the outlet of the second sludge delivery pump via a pipeline, and a sixth manual ball valve is arranged on the pipeline; The desulfurizer slurry supply unit includes a limestone slurry tank and a standby limestone slurry tank, wherein the limestone slurry tank is used to store the calcium-containing sludge and limestone mixed slurry from the overflow collection tank, the inlet of which is connected to the outlet of the overflow collection tank through a pipeline, and the outlet of which is connected to the inlet of the absorption tower in the desulfurization system through two parallel pipelines; The standby limestone slurry tank is used to store calcium-containing sludge from the sludge thickening tank. The outlet of the third manual ball valve and the outlet of the fifth manual ball valve are connected to the inlet of the standby limestone slurry tank through a common pipeline. A fourth pneumatic ball valve is provided on the common pipeline. The outlet of the standby limestone slurry tank is connected to the inlet of the absorption tower in the desulfurization system through two parallel pipelines.

2. The system for recycling calcium-containing sludge from power plant water purification according to claim 1, characterized in that: The cyclone separation mechanism further comprises a cyclone feed box, the inlet of the cyclone feed box is connected to the outlet of the mill recirculation box through a pipeline, and the outlet of the cyclone feed box is connected to the inlet of the cyclone separator through a pipeline.

3. The system for recycling calcium-containing sludge from power plant water purification according to claim 1, characterized in that: A plurality of cyclone separators are provided, and the plurality of cyclone separators are connected in parallel.

4. The system for recycling calcium-containing sludge from power plant water purification according to claim 1, characterized in that: The desulfurizing agent grinding unit also includes a limestone feeding device for providing limestone to the limestone wet ball mill, and a discharge port of the limestone feeding device is connected to an inlet of the limestone wet ball mill through a pipeline.

5. The system for recycling calcium-containing sludge from power plant water purification according to any one of claims 1 to 4, characterized in that: A flushing component is provided at the outlet of the sludge thickening tank, and the flushing component is used for flushing the outlet pipe of the sludge thickening tank.

6. A method for recycling calcium-containing sludge from power plant water purification, characterized in that: The system according to any one of claims 1 to 5 is used to measure the density of the calcium-containing sludge in the sludge thickening tank. If the density of the calcium-containing sludge is greater than the preset density, the calcium-containing sludge is transported to the desulfurizer slurry supply unit; if the density of the calcium-containing sludge is less than or equal to the preset density, the calcium-containing sludge is transported to the mill recirculation box to be mixed with the limestone slurry ground by the limestone wet ball mill; The calcium-containing sludge and limestone mixed slurry in the mill recirculation box is sent to the cyclone separator for separation; the calcium-containing sludge and limestone mixed slurry flowing out of the top outlet of the cyclone separator enters the desulfurizer slurry supply unit, and the calcium-containing sludge and limestone mixed slurry flowing out of the bottom outlet of the separator enters the limestone wet ball mill; the limestone and calcium-containing sludge mixed material ground in the limestone wet ball mill is sent to the mill recirculation box again to complete the cycle; The mixed slurry of calcium-containing sludge and limestone in the desulfurizer slurry supply unit is sent to the desulfurization system for desulfurization; When the desulfurization system cannot consume enough calcium-containing sludge, the calcium-containing sludge in the sludge concentration tank is transported to a centrifugal dehydrator for dehydration treatment, and the dehydrated sludge is aired and then sent to the boiler for mixed combustion.

7. The method for recycling calcium-containing sludge from power plant water purification according to claim 6, characterized in that: The desulfurization system includes an absorption tower. The calcium-containing sludge and limestone mixed slurry in the desulfurizer slurry supply unit is sent to the top of the absorption tower. The calcium-containing sludge and limestone mixed slurry is sprayed from top to bottom in the absorption tower to form alkaline slurry droplets and countercurrently contacts with the flue gas entering the absorption tower. The slurry absorbs SO2 in the flue gas and reacts to generate CaSO3, which is oxidized and crystallized to generate CaSO4•2H2O, and gypsum is produced after dehydration to achieve desulfurization.

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