Industrial boiler desulfurization wastewater recovery device

Abstract

The invention relates to the technical field of sewage treatment, and discloses an industrial boiler desulfurization wastewater recovery device which comprises a triple box, a heating tank, a vacuum pump, a first-effect crystallization assembly and a mixing box, the vacuum pump is communicated with the heating tank through a pipeline, and the vacuum pump is used for pumping boiler wastewater into the heating tank and boiling the boiler wastewater; the heating tank is used for providing a steam heat source for the first-effect crystallization assembly, the first-effect crystallization assembly is used for evaporating and concentrating desulfurization wastewater to separate out sodium sulfate crystals, and the mixing box is used for introducing boiler wastewater. The boiler waste water is used for providing heat for sodium sulfate evaporative crystallization of the desulfurization waste water, calcium and magnesium ions in the boiler waste water are removed through sodium sulfate obtained through evaporative crystallization of the desulfurization waste water, and therefore the heat of the boiler waste water is reasonably utilized, and a sodium sulfate product obtained through evaporation of the desulfurization waste water is reasonably utilized; the cost of treating the boiler wastewater by using chemicals is reduced, and meanwhile, energy and resources are saved.

Description

Technical Field

[0001] The present application relates to the field of sewage treatment technology, and in particular to an industrial boiler desulfurization wastewater recovery device. Background Art

[0002] Coal-fired power plants will produce a large amount of sulfur dioxide emissions during operation. In order to reduce the emission of this harmful gas, flue gas desulfurization technology is usually used. Common flue gas desulfurization methods include wet, dry and semi-dry methods. Among them, wet desulfurization is one of the most widely used technologies. Its principle is to use lime slurry to atomize and spray in the desulfurization tower, and react with sulfur dioxide in the flue gas to generate calcium sulfite or calcium sulfate, thereby achieving the purpose of removing sulfur dioxide. However, during the desulfurization process, the harmful substances in the desulfurization tower will continue to accumulate and the concentration will continue to increase. In order to reduce the concentration of accumulation, reduce corrosion and blockage of the equipment, and discharge the fly ash accumulated in the flue gas, the desulfurization equipment will regularly discharge a certain amount of desulfurization wastewater.

[0003] Therefore, desulfurization wastewater has the following characteristics: 1. High suspended solids content. Desulfurization wastewater contains a lot of fly ash, so there are more suspended solids in the wastewater; 2. High inorganic salt content. The main salt ions in desulfurization wastewater are calcium ions, magnesium ions, sodium ions, chloride ions, sulfate ions and sulfite ions; 3. Water quality is easy to scale. The content of calcium ions, magnesium ions and sulfate ions in desulfurization wastewater is relatively high, and calcium sulfate is often in an oversaturated state, which is very easy to scale; 4. The content of multiple heavy metals exceeds the standard.

[0004] In the related art, a Chinese utility model patent with the authorization publication number CN212403716U discloses a desulfurization wastewater recovery and treatment system, which includes a boiler wastewater drainer, a desulfurization wastewater pool, a dosing pool and a softening water processor. The desulfurization wastewater pool is used to store desulfurization wastewater, and the boiler wastewater drainer is used to discharge boiler wastewater into the desulfurization wastewater pool, and the calcium and magnesium ions in the boiler wastewater react with the sulfites and sulfates in the desulfurization wastewater, thereby removing the sulfites and sulfates in the desulfurization wastewater pool. The dosing pool is used to store alkaline solutions, such as calcium hydroxide, sodium hydroxide, etc., which can be transported to the desulfurization wastewater pool to reduce the heavy metal ions in the desulfurization wastewater to produce corresponding hydroxide precipitates. The softening water processor is used to remove hardness ions in the desulfurization wastewater, mainly calcium and magnesium ions, to achieve the purpose of reducing the scaling tendency of the wastewater. Commonly used softening treatment agents include sodium hydroxide plus sodium carbonate or slaked lime plus sodium carbonate. The hydroxide ions and carbonate ions in the agents can react with calcium and magnesium ions to form magnesium hydroxide and calcium carbonate precipitates.

[0005] In view of the above-mentioned related technologies, the inventors found that there are some problems with the scheme: 1. The scheme uses a softening water processor to remove the calcium and magnesium ions originally contained in the desulfurization wastewater, and then uses the calcium and magnesium ions in the boiler wastewater to react with the sulfites and sulfates in the desulfurization wastewater to remove the sulfites and sulfates in the desulfurization wastewater pool. Although it saves the boiler wastewater recovery and treatment equipment, it will cause the content of calcium and magnesium ions in the desulfurization wastewater to increase greatly, and the consumption of softening treatment agents put into the softening water processor and the alkaline solution transported from the medicine pool will increase greatly. Compared with only treating the calcium and magnesium ions in the desulfurization wastewater, the effect is not improved, but the cost is greatly increased; 2. The scheme does not remove other pollutants contained in the boiler wastewater, but makes the pollutant composition in the desulfurization wastewater more complicated, and the recovery and treatment of the desulfurization wastewater is more troublesome; 3. Before the boiler wastewater and the desulfurization wastewater react, the scheme needs to cool the boiler wastewater first, and this part of the heat is wasted. Summary of the invention

[0006] In order to solve the above problems, the present application provides an industrial boiler desulfurization wastewater recovery device.

[0007] The industrial boiler desulfurization wastewater recovery device provided in this application adopts the following technical solution: An industrial boiler desulfurization wastewater recovery device comprises a triple box, a heating tank, a vacuum pump, a first-effect crystallization component and a mixing box, wherein the triple box is used to precipitate calcium and magnesium ions, heavy metal ions and suspended matter in the desulfurization wastewater, the vacuum pump and the heating tank are connected by a pipeline, the vacuum pump is used to extract boiler wastewater into the heating tank and boil it, the heating tank is used to provide a steam heat source to the first-effect crystallization component, the first-effect crystallization component is used to evaporate and concentrate the desulfurization wastewater to precipitate sodium sulfate crystals, and the mixing box is used to pass boiler wastewater.

[0008] By adopting the above technical solution, after the desulfurization wastewater is passed into the triple box, a reagent is added thereto to cause the calcium and magnesium ions, heavy metal ions and suspended matter in the desulfurization wastewater to flocculate and precipitate, and the upper liquid of the clarified desulfurization wastewater enters the first-effect crystallization component for evaporation and crystallization; The vacuum pump is used to extract the air in the heating tank, making the heating tank in a negative pressure state, so as to extract the boiler waste water into the heating tank. Since the boiler waste water itself is in a high temperature state, the vacuum pump continuously extracts the air in the heating tank to reduce the pressure in the heating tank. The boiler waste water can reach a boiling state under a low pressure state, thus generating steam, which can provide a steam heat source for the first-effect evaporator, recycle the heat of the boiler waste water, avoid the waste of this part of heat, and save energy; Desulfurization wastewater can obtain sodium sulfate crystals through evaporation and crystallization in a single-effect crystallization component. At this time, the sodium sulfate crystals are put into a mixing box, and boiler wastewater is passed into the mixing box. The sodium sulfate crystals are dissolved in the boiler wastewater, and sulfate ions react with calcium ions and magnesium ions in the boiler wastewater to generate calcium sulfate and magnesium sulfate precipitates, thereby removing calcium and magnesium ions in the boiler wastewater. At the same time, the sodium sulfate product separated from the desulfurization wastewater is reasonably utilized, avoiding waste of resources and reducing the cost of treating calcium and magnesium ions in boiler wastewater.

[0009] Optionally, a preheating tank is further provided between the triple box and the first-effect crystallization assembly, the preheating tank comprising an inner preheating tank and an outer preheating tank, the inner preheating tank and the triple box are connected by a pipeline, and the outer preheating tank is used to introduce boiler waste water.

[0010] By adopting the above technical scheme, the upper clear liquid flowing out of the triple box first enters the preheating inner tank, and the boiler waste water enters the preheating outer tank, so that the heat of the boiler waste water is used to preheat the desulfurization waste water first, and then the subsequent evaporation and crystallization operation is carried out. On the one hand, the temperature of the desulfurization waste water before entering the first-effect crystallization component is increased, making it easier to reach the evaporation temperature, accelerating the evaporation and concentration process, and improving the crystallization efficiency; on the other hand, the heat of the boiler waste water can be reused for a second time, avoiding the waste of heat of the boiler waste water and saving energy.

[0011] Optionally, the first-effect crystallization component includes a first-effect evaporator, a first-effect separator, a first-effect forced circulation pump and a first centrifuge. The preheating inner tank and the shell side of the first-effect evaporator are connected by a pipeline, and a material pump is provided on the pipeline. The bottom of the first-effect evaporator and the first-effect separator are connected by a pipeline. The first-effect forced circulation pump is used to transport the material liquid in the first-effect separator to the first-effect evaporator. The first centrifuge is connected to the bottom of the first-effect separator through a pipeline, and the discharge port of the first centrifuge is connected to the feed port of the mixing box.

[0012] By adopting the above technical scheme, the steam in the heating tank is transported to the shell side of the first-effect evaporator through a pipeline, the desulfurization wastewater in the preheating tank is transported to the first-effect evaporator through a material pump after being preheated, the first-effect evaporator evaporates and concentrates the desulfurization wastewater, and the gas-liquid mixed desulfurization wastewater is transported to the first-effect separator through a pipeline for gas-liquid separation. The first-effect forced circulation pump sends the liquid separated by the first-effect separator to the first-effect evaporator again for evaporation and concentration, and the desulfurization wastewater is continuously crystallized in this way, and finally a feed liquid containing a large amount of sodium sulfate crystals is obtained at the bottom of the first-effect separator, and the feed liquid is transported to the first centrifuge for separation of the feed liquid and the sodium sulfate crystals, thereby separating the sodium sulfate crystals, and putting them into a mixing box to react with the boiler wastewater, so as to precipitate the calcium and magnesium ions in the boiler wastewater, thereby reducing the use of reagents in the boiler wastewater treatment and reducing the cost; at the same time, the sodium sulfate product separated from the desulfurization wastewater is reasonably utilized, avoiding waste of resources.

[0013] Optionally, the first-effect crystallization component also includes a cooling tank, a condenser and a second centrifuge. A material pump is arranged between the cooling tank and the first centrifuge. The cooling tank includes an inner cooling tank and an outer cooling tank. The condenser is used to introduce condensed water into the outer cooling tank. The discharge port of the inner cooling tank is connected to the feed port of the second centrifuge through a pipeline, and the discharge port of the second centrifuge is also connected to the feed port of the mixing box.

[0014] By adopting the above technical scheme, the mother liquor separated by the first centrifuge is sent to the cooling tank through the material pump, and the cooling tank is cooled to 35 degrees by the cooling water provided by the condenser. The sodium sulfate in the mother liquor is frozen and crystallized to obtain a feed liquid containing a small amount of sodium sulfate crystals, so that the sodium sulfate in the desulfurization wastewater is fully crystallized and precipitated. The feed liquid after crystallization in the cooling tank enters the second centrifuge, and the sodium sulfate crystals obtained by centrifugation are then transported to the mixing box. After cooling and crystallization, more sulfate ions are separated from the desulfurization wastewater, and the precipitation of calcium and magnesium ions in the boiler wastewater is also more sufficient, which effectively reduces the cost of softening the boiler wastewater.

[0015] Optionally, a second-effect crystallization component is also included, which includes a second-effect evaporator, a second-effect separator and a second-effect forced circulation pump. The steam inlet of the shell side of the second-effect evaporator is connected to the steam outlet of the first-effect separator through a pipeline, and the bottom of the second-effect evaporator and the second-effect separator are connected through a pipeline. The second-effect forced circulation pump is used to transport the liquid in the second-effect separator to the second-effect evaporator.

[0016] By adopting the above technical scheme, the mother liquor separated by the second centrifuge is transported to the second-effect evaporator through the material pump for further evaporation and crystallization, and the steam separated by the first-effect separator is transported to the second-effect evaporator as an evaporation heat source, so that the steam discharged from the first-effect separator is fully utilized, saving energy; the gas-liquid mixed mother liquor in the second-effect evaporator enters the second-effect separator for gas-liquid separation, and the second-effect forced circulation pump sends the liquid separated by the second-effect separator into the second-effect evaporator again for evaporation and concentration, and the cycle is repeated, the desulfurization wastewater is continuously crystallized, and finally sodium chloride crystals are obtained at the bottom of the second-effect separator, completing the salt separation operation of the desulfurization wastewater.

[0017] Optionally, the steam outlet of the second-effect separator is connected to the steam inlet of the condenser, the condenser is configured as an air-type condenser, and the liquid outlet of the condenser is connected to the water inlet of the cooling outer tank through a pipeline.

[0018] By adopting the above technical solution, the steam discharged from the second-effect separator is transported to the condenser through a pipeline for cooling. After cooling, the steam becomes liquid and is discharged from the water outlet of the condenser into the cooling tank, providing cooling water for the cooling tank, so that this part of the water source can be reused, and there is no need to provide a separate cooling water source for the cooling tank, thereby saving water resources.

[0019] Optionally, the first-effect crystallization assembly further includes a water collecting tank, the water inlet of the water collecting tank is connected to the shell-side condensed water outlet of the first-effect evaporator and the second-effect evaporator through a pipeline, and the water outlet of the water collecting tank is connected to the preheating outer tank through a pipeline.

[0020] By adopting the above technical solution, during the evaporation process, after the steam in the first-effect evaporator and the second-effect evaporator is condensed into condensed water, its temperature is still relatively high. In order to avoid wasting this part of heat, this part of condensed water can be transported to the water collecting tank and then to the preheating outer tank, providing a heat source for preheating the desulfurization wastewater and saving energy.

[0021] Optionally, the reagent put into the triple box includes sodium hypochlorite solution.

[0022] By adopting the above technical scheme, sodium hypochlorite solution is added into the triple box, so that the sulfite ions in the desulfurization wastewater can be oxidized into sulfate ions, thereby obtaining more sodium sulfate crystals, increasing the number of sulfate ions reacting with boiler wastewater, and more fully settling the calcium and magnesium ions in the boiler wastewater, effectively reducing the cost of softening the boiler wastewater; at the same time, the sulfite ions in the desulfurization wastewater are also removed and reasonably utilized.

[0023] In summary, the present application includes at least one of the following beneficial technical effects: 1. Desulfurization wastewater can be evaporated and crystallized in a single-effect crystallization component to obtain sodium sulfate crystals. At this time, the sodium sulfate crystals are put into a mixing box, and boiler wastewater is passed into the mixing box. The sodium sulfate crystals are dissolved in the boiler wastewater, and the sulfate ions react with the calcium ions and magnesium ions in the boiler wastewater to generate calcium sulfate and magnesium sulfate precipitation, thereby removing the calcium and magnesium ions in the boiler wastewater. At the same time, the sodium sulfate product separated from the desulfurization wastewater is reasonably utilized, avoiding waste of resources and reducing the cost of treating calcium and magnesium ions in boiler wastewater; 2. The mother liquor separated by the first centrifuge is pumped into the cooling tank through the material pump, and the cooling tank is cooled to 35 degrees by the cooling water provided by the condenser. The sodium sulfate in the mother liquor is frozen and crystallized to obtain a feed liquid containing a small amount of sodium sulfate crystals, so that the sodium sulfate in the desulfurization wastewater is fully crystallized and precipitated. The feed liquid after crystallization in the cooling tank enters the second centrifuge, and the sodium sulfate crystals obtained by centrifugation are then transported to the mixing box. After cooling and crystallization, more sulfate ions are separated from the desulfurization wastewater, and the precipitation of calcium and magnesium ions in the boiler wastewater is also more sufficient, which effectively reduces the cost of softening the boiler wastewater; 3. The steam discharged from the second-effect separator is transported to the condenser through a pipeline for cooling. After cooling, the steam becomes liquid and is discharged from the water outlet of the condenser into the cooling tank, providing cooling water for the cooling tank, so that this part of the water source can be reused, and there is no need to provide cooling water for the cooling tank separately, thereby saving water resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the embodiment of the present application; Figure 2 yes Figure 1 A partial enlarged view of the cross-sectional view of part A, mainly used to show the liquid level sensor.

[0025] Explanation of the reference numerals: 1. triple box; 11. neutralization box; 12. reaction box; 13. flocculation box; 2. heat recovery component; 21. heating tank; 22. vacuum pump; 23. water inlet electric control valve; 24. liquid level sensor; 25. preheating tank; 251. preheating inner tank; 252. preheating outer tank; 26. material pump; 27. water outlet valve; 3. first effect crystallization component; 31. first effect evaporator; 32. first effect separator; 33. first effect forced circulation pump; 34. first centrifuge; 35. cooling tank; 351. cooling inner tank; 352. cooling outer tank; 36. second centrifuge; 37. water collecting tank; 38. condenser; 4. mixing box; 5. second effect crystallization component; 51. second effect evaporator; 52. second effect separator; 53. second effect forced circulation pump. DETAILED DESCRIPTION

[0026] The following combination Figure 1 and Figure 2This application is described in further detail.

[0027] The embodiment of the present application discloses an industrial boiler desulfurization wastewater recovery device.

[0028] Reference Figure 1 , an industrial boiler desulfurization wastewater recovery device includes a triple box 1, a heat recovery component 2, a first-effect crystallization component 3, a mixing box 4 and a second-effect crystallization component 5. The desulfurization wastewater first enters the triple box 1 for pretreatment, and the calcium ions, magnesium ions and heavy metal ions in the desulfurization wastewater are generated and precipitated by adding reagents. The clarified desulfurization wastewater then enters the first-effect crystallization component 3, and the heat recovery component 2 is used to recover the heat of the boiler wastewater and supply the first-effect crystallization component 3, so that the desulfurization wastewater can be crystallized and separated in the first-effect crystallization component 3, thereby obtaining sodium sulfate crystals and mother liquor, and on the other hand, cooling the boiler wastewater. The sodium sulfate crystals are sent to the mixing box 4, and the boiler wastewater after cooling is also sent to the mixing box 4. At this time, the sodium sulfate crystals are dissolved in the boiler wastewater, and the sulfate ions react with the calcium ions and magnesium ions in the boiler wastewater to form precipitation, thereby removing the calcium ions and magnesium ions in the boiler wastewater. The mother liquor continues to enter the second-effect crystallization component 5, and the second-effect crystallization component 5 continues to evaporate and crystallize the mother liquor, at which time sodium chloride crystals can be obtained, completing the salt separation process.

[0029] Reference Figure 1 The triple box 1 includes a neutralization box 11, a reaction box 12 and a flocculation box 13. The desulfurized wastewater first enters the neutralization box 11. Alkaline substances such as lime milk are added to the neutralization box 11 to adjust the pH value of the desulfurized wastewater to above 9.0. In an alkaline environment, calcium ions, magnesium ions and most heavy metals form slightly soluble hydroxides and precipitate from the wastewater. In addition, in order to facilitate subsequent crystallization treatment, sodium hypochlorite solution can be added to the neutralization box 11 to oxidize sulfite ions into sulfate ions. The upper liquid separated from the neutralization box 11 flows into the reaction box 12, and organic sulfur is added to the reaction box 12 to remove the residual heavy metals that cannot be precipitated in the form of hydroxides in the form of sulfide precipitation. At the same time, a coagulant is added to accelerate the sedimentation of the suspended compound particles to form a solid flocculation structure. The upper layer of liquid separated from the reaction box 12 then flows into the flocculation box 13, where a coagulant is added to carry out a flocculation reaction under low-speed stirring to promote the solid flocculation structure to form a larger flocculation state. Under the action of gravity, the flocculants are deposited at the bottom and concentrated into sludge by gravity for subsequent treatment, and the clarified wastewater at the top is transported to the first-effect crystallization component 3 for crystallization.

[0030] Reference Figure 1 and Figure 2The heat recovery component 2 includes a heating tank 21. A pipe is connected to the bottom feed port of the heating tank 21 for extracting boiler waste water. A water inlet electric control valve 23 is installed on the pipe. A vacuum pump 22 is connected to the air outlet at the top of the heating tank 21 through a pipe, which is used to extract air in the heating tank 21, so that the heating tank 21 is in a negative pressure state, thereby extracting boiler waste water into the heating tank 21. A liquid level sensor 24 is installed in the heating tank 21. The liquid level sensor 24 is electrically connected to the water inlet electric control valve 23. The liquid level sensor 24 is used to monitor the liquid level in the heating tank 21 and control the opening and closing of the water inlet electric control valve 23. When the liquid level in the heating tank 21 reaches a specified position, the liquid level sensor 24 controls the water inlet electric control valve 23 to close. At this time, the air in the heating tank 21 continues to be extracted. Since the boiler wastewater itself is in a high temperature state, when the pressure in the heating tank 21 is reduced, the boiler wastewater can reach a boiling state under a low pressure state, thereby generating steam. The air outlet at the top of the heating tank 21 is connected to the first-effect crystallization component 3 through a pipeline, which is used to transport the steam to the first-effect crystallization component 3 to provide a heat source for it, thereby recycling the heat of the boiler wastewater, avoiding the waste of this part of heat, and saving energy.

[0031] Reference Figure 1 The heat recovery component 2 also includes a preheating tank 25, which includes a preheating inner tank 251 and a preheating outer tank 252. A material pump 26 is provided between the flocculation box 13 and the preheating tank 25. The water outlet at the top of the flocculation box 13 is connected to the water inlet of the material pump 26 through a pipeline. The water inlet at the top of the preheating inner tank 251 is connected to the water outlet of the material pump 26 through a pipeline. The supernatant in the flocculation box 13 is pumped into the preheating tank 25 through the material pump 26. The water inlet at the top of the preheating outer tank 252 is connected to a pipeline for extracting boiler waste water. The boiler waste water enters between the preheating outer tank 252 and the preheating inner tank 251 to preheat the desulfurization waste water in the preheating inner tank 251. At the same time, the bottom of the heating tank 21 is also connected to the water inlet at the top of the preheating outer tank 252 through a pipe, and a water outlet valve 27 is installed on the pipe. When the water outlet valve 27 is opened, the remaining boiler waste water in the heating tank 21 also enters the preheating outer tank 252 to preheat the desulfurization wastewater.

[0032] Reference Figure 1The first-effect crystallization assembly 3 includes a first-effect evaporator 31, a first-effect separator 32, a first centrifuge 34, a cooling tank 35 and a second centrifuge 36. A material pump 26 is also provided between the preheating tank 25 and the first-effect evaporator 31. The bottom discharge port of the preheating inner tank 251 is connected to the water inlet of the material pump 26. The top liquid inlet of the first-effect evaporator 31 is connected to the water outlet of the material pump 26 through a pipeline. The desulfurized wastewater is pumped into the heat exchange tube of the first-effect evaporator 31 through the material pump 26. The steam outlet provided at the top of the heating tank 21 is connected to the steam inlet of the shell side of the first-effect evaporator 31 through a pipeline. The steam enters the shell side of the first-effect evaporator 31, heats the desulfurized wastewater in the first-effect evaporator 31, and turns it into a steam state. After the desulfurized wastewater is partially evaporated, the liquid wastewater flows into the bottom of the first-effect evaporator 31. The discharge port at the bottom of the first-effect evaporator 31 is connected to the feed port at the bottom of the first-effect separator 32 through a pipeline, and the gas-liquid mixed desulfurization wastewater enters the first-effect separator 32 for gas-liquid separation. A first-effect forced circulation pump 33 is arranged between the first-effect separator 32 and the first-effect evaporator 31, and the feed port of the first-effect forced circulation pump 33 and the bottom liquid outlet of the first-effect separator 32 are connected through a pipeline, and the discharge port of the first-effect forced circulation pump 33 and the feed liquid inlet at the top of the first-effect evaporator 31 are connected through a pipeline, so that the liquid separated by the first-effect separator 32 is sent to the first-effect evaporator 31 again for evaporation and concentration, and the desulfurization wastewater is continuously crystallized in this way, and finally a feed liquid containing a large amount of sodium sulfate crystals is obtained at the bottom of the first-effect separator 32, and the feed liquid is sent to the first centrifuge 34 through the material pump 26 for separation of the feed liquid and the sodium sulfate crystals.

[0033] Reference Figure 1 , the separated sodium sulfate crystals are sent to the mixing box 4, and the separated mother liquor is sent to the cooling tank 35 through the material pump 26. The cooling tank 35 includes a cooling inner tank 351 and a cooling outer tank 352. The cooling outer tank 352 cools the mother liquor to 35 degrees, so that the sodium sulfate in the mother liquor is frozen and crystallized to obtain a feed liquid containing a small amount of sodium sulfate crystals. The bottom discharge port of the cooling tank 35 and the top feed port of the second centrifuge 36 are connected by a pipeline. The feed liquid crystallized by the cooling tank 35 enters the second centrifuge 36, and the obtained sodium sulfate crystals are transported to the mixing box 4. The mother liquor separated by the second centrifuge 36 enters the second effect crystallization component 5 for further evaporation and crystallization.

[0034] Reference Figure 1The sodium sulfate crystals separated from the first centrifuge 34 and the second centrifuge 36 are transported to the mixing box 4, and the boiler waste water heated by the preheating tank 25 is also transported to the mixing box 4 through the material pump 26. At this time, the heat in the boiler waste water has been absorbed by the desulfurization waste water, the temperature of the boiler waste water drops, the sodium sulfate crystals are dissolved in the boiler waste water, and the sulfate ions react with the calcium ions and magnesium ions in the boiler waste water to generate calcium sulfate and magnesium sulfate precipitation, thereby removing the calcium and magnesium ions in the boiler waste water. At the same time, the sodium sulfate product separated from the desulfurization waste water is reasonably utilized, avoiding waste of resources and reducing the cost of treating calcium and magnesium ions in the boiler waste water.

[0035] Reference Figure 1 The second-effect crystallization assembly 5 includes a second-effect evaporator 51 and a second-effect separator 52. The steam outlet of the heating tank 21 is connected to the steam inlet of the shell side of the second-effect evaporator 51 through a pipeline. The steam outlet at the top of the first-effect separator 32 is also connected to the steam inlet of the shell side of the second-effect evaporator 51 through a pipeline. The heating tank 21 and the first-effect separator 32 both provide steam for the second-effect evaporator 51. The mother liquor separated from the second centrifuge 36 enters the second-effect evaporator 51 through the material pump 26, and the second-effect evaporator 51 continues to evaporate and concentrate the mother liquor. The bottom discharge port of the second-effect evaporator 51 is connected to the bottom feed port of the second-effect separator 52 through a pipeline, and the gas-liquid mixed mother liquor enters the second-effect separator 52 for gas-liquid separation. A second-effect forced circulation pump 53 is arranged between the second-effect separator 52 and the second-effect evaporator 51, and the feed port of the second-effect forced circulation pump 53 and the bottom liquid outlet of the second-effect separator 52 are connected through a pipeline, and the discharge port of the second-effect forced circulation pump 53 and the top liquid inlet of the second-effect evaporator 51 are connected through a pipeline, so that the liquid separated by the second-effect separator 52 is sent to the second-effect evaporator 51 again for evaporation and concentration, and the cycle is repeated, the desulfurization wastewater is continuously crystallized, and finally sodium chloride crystals are obtained at the bottom of the second-effect separator 52.

[0036] Reference Figure 1 The first-effect crystallization component 3 also includes a water collecting tank 37. During the evaporation process, after the steam in the first-effect evaporator 31 and the second-effect evaporator 51 is condensed into condensed water, its temperature is still relatively high. In order to avoid wasting this part of heat, the condensed water outlet at the bottom of the shell of the first-effect evaporator 31 and the second-effect evaporator 51 and the water inlet at the top of the water collecting tank 37 are connected by pipes, and the water outlet at the bottom of the water collecting tank 37 and the water inlet of the preheating outer tank 252 are also connected by pipes. The condensed water collected in the water collecting tank 37 is transported to the preheating outer tank 252 through the material pump 26 to provide a heat source for preheating the desulfurization wastewater.

[0037] Reference Figure 1The first-effect crystallization assembly 3 also includes a condenser 38, which is set as an air-type condenser 38. The steam discharged from the second-effect separator 52 is transported to the condenser 38 through a pipeline for cooling. After the steam is cooled, it becomes liquid and is discharged from the water outlet of the condenser 38. The water outlet of the condenser 38 is connected to the water inlet of the cooling outer tank 352 through a pipeline to provide cooling water for the cooling tank 35, so that this part of the water source can be reused, and there is no need to provide a separate cooling water source for the cooling tank 35, thereby saving water resources. This part of the water source is a water source after pretreatment and evaporation, which meets the discharge standard. After the cooling tank 35 is used, it can be discharged from the drain at the bottom of the cooling tank 35 or provide water for the boiler equipment.

[0038] The implementation principle of the industrial boiler desulfurization wastewater recovery device in the embodiment of the present application is as follows: the desulfurization wastewater is first transported to the triple tank 1, and reagents are added to the triple tank 1 in sequence to cause the calcium and magnesium ions, heavy metal ions and suspended matter in the desulfurization wastewater to form flocculation precipitation, and sodium hypochlorite solution is added to oxidize the sulfite ions into sulfate ions for subsequent crystallization treatment. The clarified upper layer liquid of the triple tank 1 is transported to the preheating inner tank 251 through the material pump 26. A portion of the boiler wastewater is transported to the preheating outer tank 252 through a pipeline to preheat the desulfurization wastewater in the preheating tank 25.

[0039] The vacuum pump 22 is turned on to make the heating tank 21 in a negative pressure state, so that the boiler wastewater is pumped into the heating tank 21. When the specified liquid level is reached, the liquid level sensor 24 controls the water inlet electric control valve 23 to close. At this time, the air in the heating tank 21 continues to be pumped. Since the boiler wastewater itself is in a high temperature state, when the pressure in the heating tank 21 is reduced, the boiler wastewater can reach a boiling state under a low pressure state, thus generating steam. The remaining boiler wastewater in the heating tank 21 also enters the preheating outer tank 252 to preheat the desulfurization wastewater.

[0040] The steam is transported to the shell side of the first-effect evaporator 31 through a pipeline. The desulfurization wastewater in the preheating tank 25 is preheated and then transported to the first-effect evaporator 31 through a material pump 26. The first-effect evaporator 31 evaporates and concentrates the desulfurization wastewater. The gas-liquid mixed desulfurization wastewater is transported to the first-effect separator 32 through a pipeline for gas-liquid separation. The steam in the first-effect separator 32 enters the shell side of the second-effect evaporator 51 as a heat source for second-effect evaporation. The first-effect forced circulation pump 33 sends the liquid separated by the first-effect separator 32 back to the first-effect evaporator 31 for evaporation and concentration. This cycle is repeated, and the desulfurization wastewater is continuously crystallized. Finally, a feed liquid containing a large amount of sodium sulfate crystals is obtained at the bottom of the first-effect separator 32. The feed liquid is sent to the first centrifuge 34 through the material pump 26 to separate the feed liquid and the sodium sulfate crystals.

[0041] The sodium sulfate crystals separated by the first centrifuge 34 are sent to the mixing box 4, and the mother liquor obtained by separation is sent to the cooling tank 35 through the material pump 26. The cooling water provided by the condenser 38 cools the cooling tank 35 to 35 degrees, and the sodium sulfate in the mother liquor is frozen and crystallized to obtain a feed liquid containing a small amount of sodium sulfate crystals. The feed liquid crystallized by the cooling tank 35 enters the second centrifuge 36, and the sodium sulfate crystals obtained by centrifugation are transported to the mixing box 4. The boiler waste water in the preheating tank 25 provides heat and the temperature drops. At this time, it is transported to the mixing box 4 through the material pump 26. The sodium sulfate crystals are dissolved in the boiler waste water, and the sulfate ions react with the calcium ions and magnesium ions in the boiler waste water to generate calcium sulfate and magnesium sulfate precipitation, thereby removing the calcium and magnesium ions in the boiler waste water. At the same time, the sodium sulfate product separated from the desulfurization waste water is reasonably utilized, avoiding waste of resources and reducing the cost of treating calcium and magnesium ions in the boiler waste water.

[0042] The mother liquor separated by the second centrifuge 36 is transported to the second-effect evaporator 51 through the material pump 26 for further evaporation and crystallization, and the steam separated by the first-effect separator 32 is transported to the second-effect evaporator 51 as an evaporation heat source, and the heating tank 21 also provides steam for the second-effect evaporator 51. The gas-liquid mixed mother liquor in the second-effect evaporator 51 enters the second-effect separator 52 for gas-liquid separation, and the second-effect forced circulation pump 53 sends the liquid separated by the second-effect separator 52 to the second-effect evaporator 51 again for evaporation and concentration, and the cycle is repeated, the desulfurization wastewater is continuously crystallized, and finally sodium chloride crystals are obtained at the bottom of the second-effect separator 52.

[0043] The steam discharged from the second-effect separator 52 is transported to the condenser 38 through a pipeline for cooling. After cooling, the steam becomes liquid and is discharged from the water outlet of the condenser 38 into the cooling tank 35, providing cooling water for the cooling tank 35, so that this part of the water source can be reused, and there is no need to provide a separate cooling water source for the cooling tank 35, thereby saving water resources.

[0044] During the evaporation process, after the steam in the first-effect evaporator 31 and the second-effect evaporator 51 is condensed into condensed water, its temperature is still relatively high. In order to avoid wasting this part of heat, this part of condensed water can be transported to the water collecting tank 37, and then transported to the preheating outer tank 252 through a water pump to provide a heat source for preheating the desulfurization wastewater.

[0045] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An industrial boiler desulfurization wastewater recovery device, characterized in that: The invention comprises a triple box (1), a heating tank (21), a vacuum pump (22), a first-effect crystallization component (3) and a mixing box (4). The triple box (1) is used to precipitate calcium and magnesium ions, heavy metal ions and suspended matter in desulfurization wastewater. The vacuum pump (22) and the heating tank (21) are connected via a pipeline. The vacuum pump (22) is used to extract boiler wastewater into the heating tank (21) and boil it. The heating tank (21) is used to provide a steam heat source to the first-effect crystallization component (3). The first-effect crystallization component (3) is used to evaporate and concentrate the desulfurization wastewater to precipitate sodium sulfate crystals. The mixing box (4) is used to introduce boiler wastewater.

2. The industrial boiler desulfurization wastewater recovery device according to claim 1 is characterized by: A preheating tank (25) is also provided between the triple header (1) and the first-effect crystallization assembly (3); the preheating tank (25) comprises an inner preheating tank (251) and an outer preheating tank (252); the inner preheating tank (251) and the triple header (1) are connected via a pipeline; the outer preheating tank (252) is used to introduce boiler waste water.

3. The industrial boiler desulfurization wastewater recovery device according to claim 2 is characterized in that: The first-effect crystallization assembly (3) comprises a first-effect evaporator (31), a first-effect separator (32), a first-effect forced circulation pump (33) and a first centrifuge (34); the preheating inner tank (251) and the shell side of the first-effect evaporator (31) are connected via a pipeline, and a material pump (26) is arranged on the pipeline; the bottom of the first-effect evaporator (31) and the first-effect separator (32) are connected via a pipeline; the first-effect forced circulation pump (33) is used to transport the liquid in the first-effect separator (32) to the first-effect evaporator (31); the first centrifuge (34) and the bottom of the first-effect separator (32) are connected via a pipeline; and the discharge port of the first centrifuge (34) is connected to the feed port of the mixing box (4).

4. The industrial boiler desulfurization wastewater recovery device according to claim 3 is characterized by: The first-effect crystallization assembly (3) further comprises a cooling tank (35), a condenser (38) and a second centrifuge (36); a material pump (26) is provided between the cooling tank (35) and the first centrifuge (34); the cooling tank (35) comprises an inner cooling tank (351) and an outer cooling tank (352); the condenser (38) is used to introduce condensed water into the outer cooling tank (352); the discharge port of the inner cooling tank (351) is connected to the feed port of the second centrifuge (36) via a pipeline; and the discharge port of the second centrifuge (36) is also connected to the feed port of the mixing box (4).

5. The industrial boiler desulfurization wastewater recovery device according to claim 4 is characterized in that: The invention also comprises a second-effect crystallization assembly (5), the second-effect crystallization assembly (5) comprising a second-effect evaporator (51), a second-effect separator (52) and a second-effect forced circulation pump (53), the steam inlet of the shell side of the second-effect evaporator (51) and the steam outlet of the first-effect separator (32) being connected via a pipeline, the bottom of the second-effect evaporator (51) and the second-effect separator (52) being connected via a pipeline, and the second-effect forced circulation pump (53) being used to transport the feed liquid in the second-effect separator (52) to the second-effect evaporator (51).

6. The industrial boiler desulfurization wastewater recovery device according to claim 5 is characterized by: The steam outlet of the second-effect separator (52) is connected to the steam inlet of the condenser (38), the condenser (38) is configured as an air-type condenser (38), and the liquid outlet of the condenser (38) is connected to the water inlet of the cooling outer tank (352) through a pipeline.

7. The industrial boiler desulfurization wastewater recovery device according to claim 5 is characterized by: The first-effect crystallization assembly (3) further comprises a water collecting tank (37), wherein a water inlet of the water collecting tank (37) is connected to shell-side condensed water outlets of the first-effect evaporator (31) and the second-effect evaporator (51) via a pipeline, and a water outlet of the water collecting tank (37) is connected to the preheating outer tank (252) via a pipeline.

8. The industrial boiler desulfurization wastewater recovery device according to claim 1 is characterized by: The reagent put into the triple box (1) includes a sodium hypochlorite solution.

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