Two-phase flow atomization desulfurization wastewater zero discharge drying system

Abstract

The utility model discloses a two -phase flow atomization desulfurization wastewater zero emission drying system belongs to desulfurization wastewater zero emission technical field, including desulfurization tower, and desulfurization tower is linked with boiler through air preheater, pretreatment mechanism, pretreatment mechanism links with desulfurization tower, solid -liquid separator, solid -liquid separator links with pretreatment mechanism, drying tower, drying tower links with solid -liquid separator, atomization mechanism, atomization mechanism sets up in drying tower, cyclone separator, cyclone separator sets up on drying tower, the utility model discloses a pretreatment mechanism is set up to the desulfurization wastewater pretreatment, and the desulfurization wastewater after processing is dried in drying tower again through atomization mechanism and carries out full atomization again, thereby make the moisture in the desulfurization wastewater can evaporate fully in shorter time, solved the low atomization efficiency of desulfurization wastewater and the high system energy consumption in the prior art, realized the technical effect of improving the efficiency of desulfurization wastewater drying evaporation, reduces the energy consumption.

Description

Technical Field

[0001] This utility model relates to the field of zero discharge of desulfurization wastewater, and in particular to a two-phase flow atomization desulfurization wastewater zero discharge drying system. Background Technology

[0002] Coal-fired power plants commonly employ limestone-gypsum wet desulfurization (FD) processes to control sulfur dioxide emissions from flue gas, generating a certain amount of FD wastewater. This wastewater primarily originates from the discharge of circulating slurry from the absorption tower, used to control the concentration balance of chloride ions and impurities in the slurry. This type of wastewater contains high concentrations of soluble salts (such as chlorides and sulfates), residual suspended solids, and trace amounts of heavy metals and harmful elements; direct discharge would cause serious environmental pollution. Traditional FD wastewater treatment methods have several shortcomings: high energy consumption, easy scaling of equipment, high treatment costs, and potential secondary pollution risks. In recent years, to achieve "zero discharge" of FD wastewater, spray drying technology has begun to be applied in the field of FD wastewater treatment. However, existing drying systems use atomization methods such as two-fluid atomizers and rotary centrifugal atomizers. Compared to two-fluid atomizers, rotary centrifugal atomizers have disadvantages such as poor atomization effect, high energy consumption, and insufficient adaptability, making it difficult to widely apply rotary atomization drying technology in the field of zero discharge of FD wastewater. Utility Model Content

[0003] The purpose of this invention is to address the shortcomings of existing technologies, such as low atomization efficiency and low thermal energy utilization efficiency for desulfurization wastewater, and to propose a two-phase flow atomization desulfurization wastewater zero-discharge drying system.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A two-phase flow atomized desulfurization wastewater zero-discharge drying system includes a desulfurization tower, which is connected to a boiler via an air preheater, and a dust collector is also connected to one end of the desulfurization tower.

[0006] A pretreatment unit, which is connected to the desulfurization tower, is used for pretreatment of desulfurization wastewater.

[0007] A solid-liquid separator, which is connected to the pretreatment mechanism;

[0008] A drying tower, which is connected to the solid-liquid separator, is used to evaporate and dry the solution flowing into the drying tower.

[0009] An atomizing mechanism is disposed inside the drying tower and is connected to the solid-liquid separator;

[0010] A cyclone separator is installed on the drying tower and connected to the pretreatment mechanism. The cyclone separator is used to separate solid particulate matter from the flue gas.

[0011] Furthermore, the pretreatment mechanism includes:

[0012] The three interconnected tanks are connected to the desulfurization tower, and the three interconnected tanks include a neutralization tank, a settling tank, and a flocculation tank.

[0013] A clarification tank is connected to the flocculation box, and the treated desulfurization wastewater is introduced into the clarification tank for sedimentation.

[0014] An evaporator, one end of which is connected to the clarification tank and the other end of which is connected to the solid-liquid separator;

[0015] A transfer pump is provided between the clarification tank and the evaporator, with both ends of the transfer pump connected to the clarification tank and the evaporator respectively. The inlet pipe of the transfer pump is located in the middle or top of one side of the clarification tank.

[0016] Furthermore, the evaporator is also connected to a cyclone separator, and the evaporator adopts a direct heating structure.

[0017] Furthermore, the atomizing mechanism includes:

[0018] A plurality of spray guns are disposed inside the drying tower for spraying concentrated wastewater;

[0019] A compressed air tank, which is connected to the gas phase inlet channel of the spray gun, is used to provide a stable air source for spraying by the spray gun.

[0020] The spray gun is a dual-fluid atomizing spray gun.

[0021] Furthermore, the drying tower is also connected to a boiler.

[0022] Furthermore, a recovery chamber is provided at the bottom of the drying tower, and the recovery chamber is connected to the drying tower.

[0023] Furthermore, the cyclone separator is also connected to the drying tower, and the cyclone separator is also connected to the recovery bin.

[0024] The beneficial effects of this utility model are as follows:

[0025] This application pre-treats desulfurization wastewater by setting up a pre-treatment mechanism. The treated desulfurization wastewater is then fully atomized in a drying tower by an atomization mechanism, so that the water in the desulfurization wastewater can be fully evaporated in a shorter time. This solves the problems of low atomization efficiency and high system energy consumption of desulfurization wastewater in the prior art, and achieves the technical effect of improving the drying and evaporation efficiency of desulfurization wastewater and reducing energy consumption. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a two-phase flow atomized desulfurization wastewater zero-discharge drying system provided in an embodiment of the present invention;

[0027] The markings in the diagram are as follows:

[0028] 1. Desulfurization tower; 11. Dust collector;

[0029] 2. Pretreatment unit; 21. Three-tank unit; 211. Neutralization tank; 212. Settling tank; 213. Flocculation tank; 22. Clarifying tank; 23. Evaporator; 24. Transfer pump;

[0030] 3. Solid-liquid separator;

[0031] 4. Drying tower; 41; Recovery bin;

[0032] 5. Atomizing mechanism; 51. Spray gun; 52. Compressed air tank;

[0033] 6. Cyclone separator;

[0034] 7. Boiler; 71. Air preheater. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0036] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0037] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0038] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0039] Reference Figure 1 As shown, a two-phase flow atomized desulfurization wastewater zero-discharge drying system, in practical applications, is used to improve the evaporation efficiency of desulfurization wastewater and make the desulfurization wastewater dry more thoroughly. It includes a desulfurization tower 1, a pretreatment mechanism 2 connected to the desulfurization tower 1, a solid-liquid separator 3 connected to the pretreatment mechanism 2, a drying tower 4 connected to the solid-liquid separator 3, an atomizing mechanism 5 disposed in the drying tower 4, and a cyclone separator 6 connected to the drying tower 4.

[0040] Specifically, the desulfurization tower 1 is connected to the boiler 7 via an air preheater 71, allowing the flue gas from the boiler 7 to flow into the desulfurization tower 1 and react with the desulfurization wastewater. It is important to understand that the boiler 7 is the source of the flue gas. When fuel (such as coal, natural gas, biomass, etc.) is burned in the furnace of the boiler 7, high-temperature flue gas is generated. The air preheater 71 can recover the heat from the flue gas, improving the combustion efficiency of the boiler 7 while reducing the flue gas temperature. Furthermore, a dust collector 11 is connected to the flue gas inlet end of the desulfurization tower 1. The dust collector 11 is used to remove dust from the flue gas flowing into the desulfurization tower 1, preventing dust from adversely affecting subsequent processes (such as abrasion of equipment, reduced absorbent activity, and contamination of the desulfurization byproduct gypsum). The pretreatment mechanism 2 is connected to the desulfurization wastewater outlet of the desulfurization tower 1. After the desulfurization wastewater flows into the pretreatment mechanism 2, it is used for pretreatment operations such as pre-concentration to obtain concentrated brine (containing a high concentration of soluble salts and a small amount of solid crystals). The solid-liquid separator 3 is connected to the pretreatment unit 2. The concentrated brine obtained after pretreatment of the desulfurization wastewater flows into the solid-liquid separator 3. The separator separates the precipitated solid particles, such as crystalline salts, from the solution. For example, the solid-liquid separator 3 is a compression separator, with its core components being a screw shaft, a double-layer filter screen, and a hydraulic sealing system. The concentrated brine is propelled and compressed by the screw, with the liquid passing through the filter screen and being discharged, while the crystalline salts are squeezed out from the discharge port of the solid-liquid separator 3. The drying tower 4 is connected to the solid-liquid separator 3 and is used to evaporate and dry the solution flowing into the drying tower 4. That is, the concentrated brine separated from the solid-liquid separator 3 can be dried through the drying tower 4. The atomizing mechanism 5 is located inside the drying tower 4 and is connected to the solid-liquid separator 3. When the concentrated brine separated from the solid-liquid separator 3 flows into the drying tower 4, the atomizing mechanism 5 atomizes the concentrated brine to improve the drying rate of the solution. The cyclone separator 6 is installed on the flue gas duct at the outlet of the drying tower 4 and is connected to the pretreatment mechanism 2, so that the solid particles in the flue gas in the drying tower 4 are separated by the centrifugal force generated by the high-speed rotation of the cyclone separator 6. The flue gas after the solid particles are separated can flow into the pretreatment mechanism 2 through the outlet of the cyclone separator 6.

[0041] More specifically, the pretreatment mechanism 2 includes a three-tank 21, a clarification tank 22 connected to the three-tank 21, an evaporator 23 connected to the clarification tank 22, and a transfer pump 24 disposed between the clarification tank 22 and the evaporator 23.

[0042] In this embodiment, the three-tank system 21 is connected to the desulfurization tower 1. The three-tank system 21 includes a neutralization tank 211, a settling tank 212, and a flocculation tank 213. The neutralization tank 211 is connected to the desulfurization tower 1. The discharged desulfurization wastewater first enters the neutralization tank 211, where an alkaline reagent is added to adjust the pH of the wastewater to neutralize free acid and preliminarily precipitate metal ions to form insoluble hydroxides. Then, it enters the settling tank 212, where an organic sulfide reagent is added to further remove heavy metal ions from the wastewater. Finally, it flows into the flocculation tank 213, where a flocculant is added to aggregate suspended particles in the wastewater. The clarification tank 22 is connected to the flocculation tank 213. The treated desulfurization wastewater is introduced into the clarification tank 22 for settling. Under gravity, the solid sludge produced by flocculation separates from the desulfurization wastewater and settles at the bottom of the clarification tank 22, while the liquid in the desulfurization wastewater floats to the top of the clarification tank 22. One end of the evaporator 23 is connected to the clarification tank 22 so that the desulfurization wastewater flows into the evaporator 23 for pre-concentration treatment. The other end is connected to the solid-liquid separator 3. After the concentrated brine enters the solid-liquid separator 3 from the evaporator 23, the crystalline salt and solid particles that have precipitated in the concentrated brine are separated. The transfer pump 24 is located between the clarification tank 22 and the evaporator 23, and both ends of the transfer pump 24 are connected to the clarification tank 22 and the evaporator 23, respectively. The transfer pump 24 is used to draw the desulfurization wastewater from the clarification tank 22 into the evaporator 23. For example, the transfer pump 24 is a centrifugal pump, which is composed of impeller, pump shaft, suction chamber and other components. The centrifugal pump does work based on centrifugal force and realizes liquid transportation through impeller rotation. The inlet pipe of the transfer pump 24 is located in the middle or top of one side of the clarification tank 22 to prevent the intake of solid sludge deposited at the bottom of the clarification tank 22.

[0043] The evaporator 23 is also connected to the cyclone separator 6. The flue gas flowing out of the cyclone separator 6 can flow into the evaporator 23 for heat exchange. The evaporator 23 adopts a direct heating structure to accelerate the heating efficiency of the desulfurization wastewater in the evaporator 23. For example, the evaporator 23 is a spray tower evaporator, which consists of a cylindrical tower body, flue gas guide, spray system and demister. The flue gas flowing out of the cyclone separator 6 can heat the desulfurization wastewater in the evaporator 23, so that some of the liquid water in the desulfurization wastewater is converted into water vapor and discharged from the air outlet at the top of the evaporator 23 into the flue between the air preheater 71 and the dust collector 11, thereby concentrating the desulfurization wastewater. After being treated by the evaporator 23, the volume and water content of the desulfurization wastewater are greatly reduced, thus forming concentrated brine.

[0044] In this embodiment, the drying tower 4 is connected to the solid-liquid separator 3, and the concentrated liquid separated by the solid-liquid separator 3 can flow into the drying tower 4 for further drying. One end of the atomizing mechanism 5 is disposed in the drying tower 4, and the other end is connected to the solid-liquid separator 3. The concentrated wastewater flowing into the drying tower 4 from the solid-liquid separator 3 is atomized by the atomizing mechanism 5 to make the concentrated wastewater dry more thoroughly. Specifically, the atomizing mechanism 5 includes several spray guns 51 and a compressed air tank 52. Several spray guns 51 are disposed in the drying tower 4 for spraying concentrated wastewater. Preferably, the spray guns 51 are dual-fluid atomizing spray guns 51, which are coaxially composed of core components such as a gas channel, a liquid channel, a mixing chamber, and an atomizing nozzle. The spray angle is between 45° and 90°. Furthermore, the dual-fluid atomizing spray gun 51 can adjust the gas-liquid ratio and droplets according to the operating conditions by using replaceable flow-limiting bushings or swirl vanes. The compressed air tank 52 is connected to the gas phase inlet channel of the spray gun 51 to provide a stable air source for spraying the spray gun 51. For example, when the concentrated wastewater enters the spray gun 51 and meets the high-speed compressed air at the nozzle outlet, the two fluids, gas and liquid, undergo strong collision and shearing. The concentrated liquid is torn into fine droplets with a diameter of about 100 micrometers or less and sprayed into the drying tower 4, so that the concentrated liquid can be completely dried in the limited space and residence time of the drying tower 4.

[0045] In some preferred embodiments, the drying tower 4 is also connected to the boiler 7. The reason for this is that the temperature of the high-temperature flue gas discharged from the boiler 7 is usually between 350 and 400°C. A portion of the high-temperature flue gas discharged from the boiler 7 can be drawn out into the drying tower 4 through the exhaust device. The flue gas then comes into contact with the atomized wastewater in parallel and co-current flow through the air inlet at the top of the drying tower 4. The droplets evaporate rapidly in the hot flue gas, and the water they carry is converted into water vapor and enters the flue gas. Meanwhile, the salts and suspended solids originally dissolved in the wastewater crystallize / dry to form solid particles. These solid particles settle to the bottom of the drying tower 4 under the action of gravity, accelerating the drying and separation of the concentrated wastewater.

[0046] In this embodiment, a recovery chamber 41 is also provided at the bottom of the drying tower 4. The recovery chamber 41 is connected to the drying tower 4 and is used to collect solid particles such as salt crystals deposited in the drying tower 4. For example, the recovery chamber 41 includes a chamber pump and a storage chamber. The chamber pump can suck the solid particles into the storage chamber for storage and transfer.

[0047] In some preferred embodiments, since the temperature of the flue gas flowing into the dryer from the boiler 7 decreases, it becomes medium-low temperature flue gas containing saturated water vapor. The flue gas discharged from the bottom of the drying tower 4 may carry trace amounts of fine particulate matter. In order to prevent subsequent equipment from being affected, the cyclone separator 6 is also connected to the drying tower 4 so that the solid particulate matter in the flue gas discharged from the drying tower 4 is separated by the cyclone separator 6. The cyclone separator 6 is also connected to the recovery bin 41. The solid particles separated by the cyclone separator 6 flow into the storage bin, while the separated flue gas flows into the pretreatment mechanism 2 through the outlet of the cyclone separator 6 for reuse.

[0048] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A two-phase flow atomized desulfurized wastewater zero discharge drying system, characterized in that, include: A desulfurization tower (1) is connected to a boiler (7) via an air preheater (71), and a dust collector (11) is also connected to one end of the desulfurization tower (1). A pretreatment unit (2) is connected to a desulfurization tower (1) and is used to pretreat desulfurization wastewater. Solid-liquid separator (3), which is connected to the pretreatment mechanism (2); Drying tower (4), which is connected to the solid-liquid separator (3), is used to evaporate and dry the solution flowing into the drying tower (4); Atomizing mechanism (5) is provided inside the drying tower (4) and is connected to the solid-liquid separator (3); Cyclone separator (6) is installed on the drying tower (4) and connected to the pretreatment mechanism (2). The cyclone separator (6) is used to separate solid particles in the flue gas.

2. The two-phase flow atomized desulfurization wastewater zero-discharge drying system according to claim 1, characterized in that, The pretreatment unit (2) includes: The three-compartment tank (21) is connected to the desulfurization tower (1). The three-compartment tank (21) includes a neutralization tank (211), a settling tank (212), and a flocculation tank (213). Clarification tank (22), which is connected to the flocculation box (213), is used to introduce the treated desulfurization wastewater into the clarification tank (22) for sedimentation; Evaporator (23), one end of which is connected to the clarification tank (22) and the other end of which is connected to the solid-liquid separator (3); A transfer pump (24) is provided between the clarifier (22) and the evaporator (23), and the two ends of the transfer pump (24) are respectively connected to the clarifier (22) and the evaporator (23). The liquid inlet pipe of the transfer pump (24) is provided in the middle or top of one side of the clarifier (22).

3. The two-phase flow atomized desulfurization wastewater zero-discharge drying system according to claim 2, characterized in that, The evaporator (23) is also connected to the cyclone separator (6), and the evaporator (23) adopts a direct heating structure.

4. The two-phase flow atomized desulfurization wastewater zero-discharge drying system according to claim 1, characterized in that, The atomizing mechanism (5) includes: A plurality of spray guns (51) are disposed inside the drying tower (4) for spraying concentrated wastewater; Compressed air tank (52), which is connected to the gas phase inlet channel of the spray gun (51) and is used to provide a stable air source for spraying the spray gun (51); The spray gun (51) is a dual-fluid atomizing spray gun (51).

5. The two-phase flow atomized desulfurization wastewater zero-discharge drying system according to claim 1, characterized in that, The drying tower (4) is also connected to the boiler (7).

6. The two-phase flow atomized desulfurization wastewater zero-discharge drying system according to claim 1, characterized in that, The bottom end of the drying tower (4) is also provided with a recovery chamber (41), which is connected to the drying tower (4).

7. A two-phase flow atomized desulfurization wastewater zero-discharge drying system according to claim 6, characterized in that, The cyclone separator (6) is also connected to the drying tower (4) and the cyclone separator (6) is connected to the recovery bin (41).

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