Jet flow impact type incineration fly ash ultrafast washing device and method

Abstract

The invention provides a jet flow impact type incineration fly ash ultrafast washing device and method. The device comprises a flue gas pressure pump, a first ejector, a second ejector, an impact tank, a gas-liquid separator and a dehydration unit. Flue gas is pressurized by a pressure pump and then enters a first ejector, carbon dioxide is injected through negative pressure of a throat part of the first ejector, the flue gas is mixed and then enters a throat part of a second ejector, fly ash slurry in a pre-slurrying tank is sucked through negative pressure of the throat part of the second ejector, and gas-liquid high-speed mixed jet flow is formed; the mixed jet flow directly impacts the liquid level through a jet flow outlet extending into the impact tank liquid, and turbulence disturbance is enhanced; and the separated flue gas returns to the incineration system, and the liquid circulates back to the impact tank through the inclined material returning pipe. The problems of ash deposition hardening and low dechlorination efficiency in a traditional water washing process are solved through the cooperation of carbon dioxide and jet flow and the negative pressure-impact coupling effect, and the device has the advantages of being short in water washing time, small in occupied area, low in energy consumption and the like and is suitable for incineration fly ash resourceful treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and specifically designs a jet impact type incineration fly ash ultra-fast water washing device and method, which can be used for the resource treatment of incineration fly ash. Background Art

[0002] Fly ash is the fine particle residue generated during the garbage incineration process, usually containing relatively high concentrations of heavy metals, dioxins and soluble chlorides, and is listed as hazardous waste by many countries. If a large amount of fly ash is not properly treated, it will pose a serious threat to the environment.

[0003] The current treatment methods mainly include landfill treatment after stabilization treatment. However, landfill has problems such as occupying land and poor long-term stability. The emerging treatment method is the co-disposal of fly ash in cement kilns. Although the resource utilization of fly ash is realized, fly ash contains a large amount of chloride ions and heavy metals. Directly putting it into the cement kiln will affect the cement quality and production process, easily reduce the quality of clinker and cause problems such as cement kiln crusting, resulting in a low blending ratio of incineration fly ash. Therefore, pretreatment such as water washing and desalting is required before the resource utilization of fly ash to reduce the chlorine content. The chlorine content of the fly ash after water washing needs to be reduced to less than 1% to meet the requirements of co-disposal in cement kilns.

[0004] The traditional fly ash water washing method uses a large stirring tank, which occupies a large area. The traditional water washing tank relies on a paddle / frame type stirrer, which can only generate laminar flow or weak turbulence and cannot effectively break agglomerates, resulting in the internal chlorides being wrapped, and the washing effect is limited. To meet the dechlorination rate requirement, 2-3 stirring tanks need to be connected in series, with a residence time of 30-60 minutes for each stage, and the total time-consuming is 1.5-3 hours, resulting in more time required to achieve effective removal.

[0005] The energy consumption of mechanical stirring is mainly used to overcome the fluid viscosity, rather than effectively breaking particles, and the energy conversion rate is low. During the multi-stage water washing process, the material needs to be transported by a pump between each layer of water washing tanks. The fly ash washing liquid usually contains a relatively high concentration of solid particles and suspended substances, increasing the fluid viscosity and causing energy loss during the pumping process. Conventional water washing is difficult to remove Friedel salts in fly ash, and the chlorine in them is difficult to dissolve out, resulting in low chlorine removal efficiency.

[0006] In the existing stirring tank, fly ash particles are easy to deposit at the bottom of the tank body, forming a hardened layer during long-term operation, and it is necessary to frequently stop the machine for cleaning, and the equipment utilization rate is insufficient.

[0007] In summary, the existing water washing technology cannot balance the requirements of high-efficiency dechlorination, anti-deposition operation and low-energy consumption compactness, seriously restricting the fly ash resource utilization process. Summary of the Invention

[0008] In view of the above technical deficiencies, the present invention provides a jet impact type ultra-fast water washing device and method. By using this device and method, it is possible to take into account efficient dechlorination while greatly shortening the washing time, and has the technical effects of eliminating tank bottom hardening and low energy consumption and compactness.

[0009] To achieve the above technical objectives, the present invention adopts the following technical means: To achieve the above object, the present invention provides the following technical solution: A jet impact type ultra-fast water washing device for incineration fly ash, comprising: A flue gas pressurizing unit, which is provided with a flue gas inlet and a pressurized flue gas outlet; A first ejector, the first ejector inlet thereof is connected to the pressurized flue gas outlet of the flue gas pressurizing unit, and the throat of the first ejector is connected to a carbon dioxide delivery pipe; A second ejector, the second ejector inlet thereof is connected to the outlet of the first ejector, and the throat of the second ejector is connected to the discharge port of a prefabricated slurry tank through a feed pipe. A fly ash slurry is prefabricated in the prefabricated slurry tank; An impact tank, which is arranged below the second ejector. The inside of the impact tank is provided with washing liquid. The outlet of the second ejector extends above the liquid level of the washing liquid inside the impact tank. The top of the impact tank is provided with an impact tank flue gas outlet. The impact tank flue gas outlet is connected to the inlet of a gas-liquid separator through a first flue gas pipe. The gas-liquid separator is provided with a gas-liquid separator flue gas outlet. The gas-liquid separator flue gas outlet returns to the incineration furnace through a second flue gas pipe; a drain port is provided at the bottom of the gas-liquid separator. The drain port is connected to a refeed inlet on one side of the impact tank through a return pipe. The refeed inlet is located below the liquid level of the washing liquid inside the impact tank; a slurry outlet is provided at the bottom of the impact tank; A dehydration unit, which performs solid-liquid separation on the washed slurry discharged from the slurry outlet at the bottom of the impact tank. The separated filtrate is discharged for external treatment, and the dehydrated ash residue is output for resource utilization.

[0010] Beneficial effects: The present invention solves the problems of ash residue deposition and hardening and low dechlorination efficiency in the traditional water washing process through the synergistic jet of carbon dioxide and the coupling effect of negative pressure-impact. It has the advantages of short water washing time, small floor area, low energy consumption, etc., and is suitable for the resource treatment of incineration fly ash. Specifically: The present invention increases the flue gas flow rate through the flue gas pressurization unit, thereby increasing the flow rate and negative pressure value at the throats of the first ejector and the second ejector, strengthening the mixing of gas-liquid-solid three phases, and inducing cavitation. The high-speed gas and flue gas at the throat of the second ejector entrain the liquid-solid two phases to form a high-intensity shear field, and the particles are torn by the shear force at the gas-liquid interface; the negative pressure area at the throat of the ejector induces cavitation bubbles, and the bubbles enter the mixing section with the fluid. As the pressure increases and the external pressure is much higher than the internal pressure, the bubbles collapse instantaneously, releasing energy, destroying the chloride salt coating structure. The superposition of shear and cavitation can greatly improve the dissolution efficiency of chloride salts.

[0011] In the impact tank of the present invention, the jet flow at the outlet of the second ejector directly impacts the liquid surface to generate large vortices, promoting the global movement of particles, accelerating the stripping of surface chloride salts, and increasing the dissolution rate of chlorine.

[0012] In an optional embodiment, the prefabricated slurry tank is further provided with an ash inlet and a water inlet, and a stirrer is arranged inside the prefabricated slurry tank.

[0013] Beneficial effects: The present invention sets an ash inlet and a water inlet on the prefabricated slurry tank, and a stirrer is arranged inside the prefabricated slurry tank, which can realize the continuous supply of fly ash slurry.

[0014] In an optional embodiment, the ratio of the throat diameter of the first ejector to the inlet diameter of the first ejector is 1:2 - 1:4.

[0015] Beneficial effects: The ratio of the throat diameter of the first ejector to the inlet diameter of the first ejector in the present invention is 1:2 - 1:4, which can maintain an appropriate pressure difference without sacrificing the flow rate, thereby providing sufficient kinetic energy to enter the second ejector.

[0016] In an optional embodiment, the ratio of the throat diameter of the second ejector to the inlet diameter of the second ejector is 1:2 - 1:4, and the partial length from the throat of the second ejector to before the outlet of the second ejector is 5 - 8 times the inlet diameter of the second ejector.

[0017] Beneficial effects: The ratio of the throat diameter of the second ejector to the inlet diameter of the second ejector in the present invention is 1:2 - 1:4. The moderate throat diameter can effectively maintain the high-speed jet of the fluid, while avoiding too fast flow rate caused by too small diameter or too slow flow rate caused by too large diameter, which helps to enhance the turbulence degree of the fluid and promote the efficient mixing between the flue gas and the fly ash slurry.

[0018] In an optional embodiment, the feeding pipe and the return pipe are inclined, and the angle with the horizontal direction is not less than 30°.

[0019] Beneficial effects: The feeding pipe and the return pipe are inclined, ensuring the smooth transportation of the fly ash slurry and the liquid after gas-liquid separation.

[0020] In an alternative embodiment, the flue gas pressurizing unit is an air pump.

[0021] Advantageous effects: In the present invention, the flue gas pressurizing unit is an air pump, which can provide a constant gas flow rate and pressure, avoiding the problem of unstable jet flow caused by pressure fluctuations in traditional fans.

[0022] The present invention further discloses a method for ultra-fast washing of incineration fly ash based on jet impingement, comprising the following steps: S1. Using the flue gas pressurizing unit to pressurize the flue gas to 0.3 - 0.8 MPa and then injecting it into the first ejector. The throat of the first ejector sucks in carbon dioxide and mixes it with the flue gas. In the mixed flue gas, the carbon dioxide concentration is ≥ 20%; S2. The mixed flue gas ejected by the first ejector is mixed with the fly ash slurry in the prefabricated slurry tank at the throat of the second ejector to form a high-speed gas-liquid two-phase mixed jet; S3. The gas-liquid two-phase mixed jet ejected by the second ejector impacts into the impact tank from above the liquid level of the impact tank to achieve enhanced turbulence, further crushing the fly ash particles in the fly ash slurry; S4. The flue gas in the impact tank returns to the incineration system after gas-liquid separation, and the liquid returns to the impact tank through the return pipe; S5. The washed slurry is subjected to dehydration treatment, the fly ash is recycled, and the filtrate is discharged for reprocessing.

[0023] Advantageous effects: The air pump in the present invention pressurizes the flue gas to 0.3 - 0.8 MPa, significantly increasing the flow velocity and negative pressure value at the throats of the first ejector and the second ejector, thereby strengthening the mixing of gas-liquid-solid three phases and inducing cavitation.

[0024] The high-speed gas flue gas at the throat of the second ejector entrains the liquid-solid two phases, forming a high-intensity shear field, tearing the particles through the shear force at the gas-liquid interface; the negative pressure zone at the throat of the ejector induces cavitation bubbles. The bubbles enter the mixing section with the fluid, the pressure increases, and the external pressure is much higher than the internal pressure. The bubbles collapse instantaneously, releasing energy, destroying the chloride salt coating structure. The superposition of shear and cavitation greatly improves the dissolution efficiency of chloride salts.

[0025] By introducing carbon dioxide through the first ejector, the carbon dioxide content in the flue gas is increased to more than 20%, which is beneficial for subsequent regulation of the pH of the slurry, thereby dissolving insoluble Friedel's salt and increasing the dissolution rate of insoluble chlorine.

[0026] In the impact tank, the jet flow at the outlet of the second ejector directly impacts the liquid surface, generating strong turbulent disturbances. Micro-bubbles are injected into the slurry, enhancing the gas-liquid-solid three-phase synergistic disturbance effect, promoting the global movement of particles, and accelerating the stripping of surface chloride salts.

[0027] In addition, the gas (CO 2 / flue gas) below the liquid surface is impacted to form an upward bubble flow, which prevents particle settlement; the feed pipe / return pipe is inclined to maintain the solid phase suspension and prevent pipeline blockage. The liquid in the whole system circulates at a high speed, which can effectively eliminate the tank bottom hardening and greatly shorten the water washing time.

[0028] By using the carbon dioxide in the flue gas and the introduced carbon dioxide, the removal rate of Friedel's salt in fly ash can be increased from 51% to 95%, and the dissolution rate of insoluble chlorine in conventional water washing can be significantly increased.

[0029] In an optional embodiment, the gas-liquid volume ratio of the mixed flue gas to the fly ash slurry in the step S2 is 1:5 - 1:10, and the pH value of the slurry after mixing is less than 7.

[0030] Beneficial effects: The gas-liquid volume ratio of the mixed flue gas to the fly ash slurry in the present invention is 1:5 - 1:10, which can dynamically adjust the pH of the slurry, ensure that the pH value of the slurry is less than 7, and avoid the energy consumption waste caused by excessive liquid transportation. The insoluble Friedel's salt is removed, the dissolution rate of chlorides is increased, and the system energy consumption is reduced at the same time. Description of the Drawings

[0031] Figure 1 is a schematic diagram of the jet impact type incineration fly ash ultra-fast water washing device of the present invention; Among them, 1. Flue gas pressurization unit, 2. First ejector, 3. Second ejector, 4. Prefabricated slurry tank, 5. Stirrer, 6. Feed pipe, 7. Gas-liquid separator, 8. Impact tank, 9. Dewatering unit; 10. Return pipe; 1-1. Flue gas inlet, 1-2. Pressurized flue gas outlet, 2-1. First ejector inlet, 2-2. First ejector throat, 2-3 First ejector outlet, 3-1. Second ejector inlet, 3-2. Second ejector throat, 3-3. Second ejector outlet, 4-1. Ash inlet, 4-2. Water inlet, 4-3. Prefabricated slurry tank outlet, 7-1. Gas-liquid separator inlet, 7-2. Gas-liquid separator flue gas outlet, 7-3. Gas-liquid separator liquid outlet, 8-1. Impact tank inlet, 8-2. Impact tank flue gas outlet, 8-3. Impact tank return inlet, 8-4. Impact tank outlet, 9-1. Dewatering unit inlet, 9-2. Water washed ash outlet, 9-3. Filtrate outlet.

[0032] Figure 2 is a test device diagram of ordinary water washing; Figure 3 is a test device diagram of carbon dioxide bubbling water washing; Figure 4 is a test device diagram of jet impact water washing. Detailed Embodiments

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the specification and specific embodiments. Embodiment

[0034] The present invention discloses a jet impact type ultra-fast water washing device for incineration fly ash. As Figure 1 shown, it mainly includes a flue gas pressurizing unit 1, a first ejector 2, a second ejector 3, a prefabricated slurry tank 4, an impact tank 8, a gas-liquid separator, and a dehydration unit 9. Among them, The flue gas pressurizing unit 1 is provided with a flue gas inlet and a pressurized flue gas outlet; For the first ejector 2, the first ejector inlet thereof is connected to the pressurized flue gas outlet of the flue gas pressurizing unit, and the first ejector throat is connected to a carbon dioxide delivery pipe; For the second ejector 3, the second ejector inlet thereof is connected to the first ejector outlet, and the second ejector throat is connected to the discharge port of the prefabricated slurry tank 4 through a feeding pipe. Fly ash slurry is prefabricated in the prefabricated slurry tank; The impact tank 8 is arranged below the second ejector. The inside of the impact tank is provided with washing liquid. The outlet of the second ejector extends above the liquid level of the washing liquid inside the impact tank. The top of the impact tank is provided with an impact tank flue gas outlet. The impact tank flue gas outlet is connected to the air inlet of the gas-liquid separator 7 through a first flue gas pipe. The gas-liquid separator is provided with a gas-liquid separator flue gas outlet. The gas-liquid separator flue gas outlet returns to the incineration furnace through a second flue gas pipe; a liquid discharge port is provided at the bottom of the gas-liquid separator. The liquid discharge port is connected to the anti-feed inlet on one side of the impact tank through a return pipe. The anti-feed inlet is located below the liquid level of the washing liquid inside the impact tank; a slurry outlet is provided at the bottom of the impact tank; The dehydration unit performs solid-liquid separation on the washed slurry discharged from the slurry outlet at the bottom of the impact tank. The separated filtrate is discharged for external treatment, and the dehydrated ash residue is output for resource utilization.

[0035] The present invention solves the problems of ash residue deposition and caking and low dechlorination efficiency in the traditional water washing process through the synergistic jet of carbon dioxide and the coupling action of negative pressure-impact. It has the advantages of short water washing time, small floor area, low energy consumption, etc., and is suitable for the resource treatment of incineration fly ash. Specifically, the present invention improves the flue gas flow rate through the flue gas pressurizing unit, thereby increasing the flow rate and negative pressure value at the throats of the first ejector and the second ejector, strengthening the mixing of gas-liquid-solid three phases, and inducing cavitation. The high-speed gas flue gas at the throat of the second ejector entrains the liquid-solid two phases to form a high-intensity shear field, and tears the particles through the shear force at the gas-liquid interface; the negative pressure area at the throat of the ejector induces cavitation bubbles. The bubbles enter the mixing section with the fluid, the pressure increases, and the external pressure is much higher than the internal pressure. The bubbles collapse instantly, releasing energy, destroying the chlorine salt coating structure. The superposition of shear and cavitation can greatly improve the dissolution efficiency of chlorine salts.

[0036] In the impact tank of the present invention, the jet flow at the outlet of the second ejector directly impacts the liquid surface to generate large vortices, promoting the global movement of particles, accelerating the stripping of surface chlorides, and increasing the dissolution rate of chlorine.

[0037] As a further preference for the technical solution of Embodiment 1 of the present invention, the prefabricated slurry tank is further provided with a dust inlet and a water inlet, and a stirrer is arranged inside the prefabricated slurry tank. By providing a dust inlet and a water inlet on the prefabricated slurry tank and arranging a stirrer inside the prefabricated slurry tank, the continuous supply of fly ash slurry can be realized.

[0038] As a further preference for the technical solution of Embodiment 1 of the present invention, the ratio of the throat diameter of the first ejector to the diameter of the first ejector inlet is 1:2 - 1:4. The ratio of the throat diameter of the first ejector to the diameter of the first ejector inlet being 1:2 - 1:4 can maintain an appropriate pressure difference without sacrificing the flow rate, thereby providing sufficient kinetic energy to enter the second ejector.

[0039] The ratio of the throat diameter of the second ejector to the diameter of the second ejector inlet is 1:2 - 1:4, and the partial length from after the throat of the second ejector until before the second ejector outlet is 5 - 8 times the diameter of the second ejector inlet.

[0040] The ratio of the throat diameter of the second ejector to the diameter of the second ejector inlet is 1:2 - 1:4. A moderate throat diameter can effectively maintain the high-speed jet of the fluid, while avoiding too fast a flow rate caused by too small a diameter or too slow a flow rate caused by too large a diameter, which helps to enhance the turbulence degree of the fluid and promote the efficient mixing between the flue gas and the fly ash slurry.

[0041] As a further preference for the technical solution of Embodiment 1 of the present invention, the feed pipe 6 and the return pipe 10 are inclined, and the angle with the horizontal direction is not less than 30°. The inclination of the feed pipe and the return pipe ensures the smooth transportation of the fly ash slurry and the liquid after gas-liquid separation.

[0042] As a further preference for the technical solution of Embodiment 1 of the present invention, the flue gas pressurization unit is an air pump. The flue gas pressurization unit being an air pump can provide a constant gas flow and pressure, avoiding the problem of unstable jet flow caused by pressure fluctuations in traditional fans.

[0043] The present invention further discloses a method for ultra-fast washing of incinerated fly ash based on jet impact, including the following steps: S1. Using the flue gas pressurization unit to pressurize the flue gas to 0.3 - 0.8 MPa and then injecting it into the first ejector. The throat of the first ejector sucks in carbon dioxide and mixes it with the flue gas. In the mixed flue gas, the carbon dioxide concentration ≥ 20%; S2. The mixed flue gas ejected by the first ejector is mixed with the fly ash slurry in the prefabricated slurry tank at the throat of the second ejector to form a high-speed gas-liquid two-phase mixed jet; S3. The gas-liquid two-phase mixed jet after being ejected by the second ejector impacts into the impact tank from above the liquid level of the impact tank, achieving turbulent intensification to further break the fly ash particles in the fly ash slurry; S4. The flue gas in the impact tank returns to the incineration system after gas-liquid separation, and the liquid returns to the impact tank through the return pipe; S5. The slurry after water washing is subjected to dehydration treatment, the fly ash is used for resource utilization, and the filtrate is discharged for reprocessing.

[0044] In the present invention, the air pump pressurizes the flue gas to 0.3 - 0.8 MPa, significantly increasing the throat flow velocity and negative pressure value of the first ejector and the second ejector, thereby strengthening the gas-liquid-solid three-phase mixing and inducing the cavitation effect.

[0045] The high-speed gas (flue gas) at the throat of the second ejector entrains the liquid-solid two-phase to form a high-intensity shear field, tearing the particles through the shear force at the gas-liquid interface; the negative pressure zone at the throat of the ejector induces cavitation bubbles, and the bubbles enter the mixing section with the fluid. As the pressure increases and the external pressure is much higher than the internal pressure, the bubbles collapse instantaneously, releasing energy, destroying the chloride salt coating structure. The superposition of the shear and cavitation effects greatly improves the dissolution efficiency of chloride salts.

[0046] By introducing carbon dioxide through the first ejector, the carbon dioxide content in the flue gas is increased to more than 20%, which is beneficial to subsequent regulation of the slurry pH, thereby dissolving the insoluble Friedel's salt and increasing the dissolution rate of insoluble chlorine.

[0047] In the impact tank, the jet at the outlet of the second ejector directly impacts the liquid surface, generating strong turbulent disturbances. Micro-bubbles are injected into the slurry, enhancing the gas-liquid-solid three-phase synergistic disturbance effect, promoting the global movement of particles, and accelerating the stripping of surface chloride salts.

[0048] In addition, the gas (CO 2 / flue gas) below the impact liquid surface forms an upward bubble flow to prevent particle settlement; the feed pipe / return pipe is inclined to maintain the suspension of the solid phase and prevent pipeline blockage. The liquid in the whole system circulates at a high speed, which can effectively eliminate the tank bottom hardening and greatly shorten the water washing time.

[0049] Using the carbon dioxide in the flue gas and the introduced carbon dioxide, the removal rate of Friedel's salt in the fly ash can be increased from 51% to 95%, greatly improving the dissolution rate of insoluble chlorine in conventional water washing.

[0050] As a further preference of the ultra-fast water washing method for incineration fly ash based on jet impingement in the present invention, in step S2, the gas-liquid volume ratio of the mixed flue gas to the fly ash slurry is 1:5 - 1:10, and the pH value of the slurry after mixing is less than 7. The gas-liquid volume ratio of the mixed flue gas to the fly ash slurry in the present invention is 1:5 - 1:10, which can dynamically adjust the pH of the slurry, ensure that the pH value of the slurry is less than 7, and avoid the energy consumption waste caused by excessive liquid transportation. It can remove insoluble Friedel's salt, improve the dissolution rate of chloride salts, and reduce the system energy consumption at the same time.

[0051] The following is a test comparison of three water washing methods: ordinary water washing method, carbon dioxide bubbling water washing method, and jet impingement ultra-fast water washing method: Ordinary water washing method: Take 30 g of fly ash by mass and place it in a beaker. Add deionized water according to the liquid-solid ratio of 3 mL / g, and add a rotor on a magnetic stirrer. Wash it at a stirring speed of 500 r / min for 30 min. The slurry is vacuum filtered and dehydrated at -0.1 MPa. Put the washed ash into an oven and bake it at 105 °C for 12 h. After drying, refer to the "Determination of Chloride Ions - (Automatic) Potentiometric Titration Method (Alternative Method)" in "Methods of Chemical Analysis of Cement" GBT176-2017 to determine the total chlorine in the washed ash.

[0052] Carbon dioxide bubbling water washing method: Take 30 g of fly ash by mass, add deionized water according to the liquid-solid ratio of 3 mL / g, and place it on a magnetic stirrer and add a rotor. Stir at a speed of 500 r / min, and carbon dioxide bubbles into the washing slurry at a flow rate of 60 ml / min. The washing time is 30 min. After washing, the slurry is vacuum filtered and dehydrated at -0.1 MPa. Put the washed ash into an oven and bake it at 105 °C for 12 h. After drying, refer to the "Determination of Chloride Ions - (Automatic) Potentiometric Titration Method (Alternative Method)" in "Methods of Chemical Analysis of Cement" GBT176-2017 to determine the total chlorine in the washed ash.

[0053] Jet impingement ultra-fast water washing: Take 30 g of fly ash by mass and place it in a prefabricated slurry tank. Add deionized water according to the liquid-solid ratio of 3 mL / g. The flue gas pressurizing pump pressurizes the flue gas to 0.6 MPa, mixes it with carbon dioxide through the first ejector. After mixing, the carbon dioxide concentration in the flue gas is 60%. The high-pressure flue gas enters the second ejector, forms a negative pressure at the throat of the second ejector to suck in the fly ash slurry, and enters the impact tank after mixing in the mixing section. After washing, the slurry is vacuum filtered and dehydrated at -0.1 MPa. Put the dehydrated washed ash into an oven and bake it at 105 °C for 12 h. After drying, refer to the "Determination of Chloride Ions - (Automatic) Potentiometric Titration Method (Alternative Method)" in "Methods of Chemical Analysis of Cement" GBT176-2017 to determine the total chlorine in the washed ash.

[0054] Table 1 Comparison of the effects of different water washing methods Index Ordinary water washing Carbon dioxide bubbling water washing Jet impact water washing Liquid-solid ratio (mL / g) 3 3 3 Carbon dioxide concentration (%) — 60 60 Washing time 30 min 30 min 10s Dechlorination rate (%) 92.7 95.1 96.7 。

Claims

1. A jet impact incineration fly ash ultra-fast water washing device, characterized in that: include: A smoke pressurizing unit (1), which is provided with a smoke inlet (1-1) and a pressurized smoke outlet (1-2); A first ejector (2), wherein the first ejector inlet (2-1) is connected to the pressurized smoke outlet (1-2) of the smoke pressurizing unit (1), and the first ejector throat (2-2) is connected to the carbon dioxide delivery pipe; A second ejector (3), wherein the second ejector inlet (3-1) is connected to the first ejector outlet (2-3), and the throat of the second ejector is connected to the discharge port (4-3) of the pre-slurry tank (4) via a feed pipe (6), wherein the pre-slurry tank (4) is provided with fly ash slurry; An impact tank (8) is arranged below the second ejector, a water wash liquid is arranged inside the impact tank, the outlet of the second ejector extends to above the liquid level of the water wash liquid inside the impact tank, a smoke outlet of the impact tank is arranged on the top of the impact tank, the smoke outlet of the impact tank is connected to the air inlet of the gas-liquid separator through a first smoke pipe, a gas-liquid separator smoke outlet (7-2) is arranged on the gas-liquid separator, and the smoke outlet of the gas-liquid separator is returned to the incineration furnace through a second smoke pipe; a liquid discharge port (7-3) is arranged at the bottom of the gas-liquid separator, the liquid discharge port is connected to a return material inlet (8-3) on one side of the impact tank through a return material pipe (10), and the return material inlet (8-3) is located below the liquid level of the water wash liquid inside the impact tank; a slurry outlet is arranged at the bottom of the impact tank; The dehydration unit (9) performs solid-liquid separation on the washed slurry discharged from the slurry outlet at the bottom of the impact tank, discharges the separated filtrate for external treatment, and outputs the dehydrated ash for resource utilization.

2. The jet impact incineration fly ash ultra-fast water washing device according to claim 1 is characterized in that: The pre-slurry tank (4) is also provided with an ash inlet (4-1) and a water inlet (4-2), and a stirrer (5) is provided inside the pre-slurry tank (4).

3. The jet impact incineration fly ash ultra-fast water washing device according to claim 1 is characterized in that: The ratio of the throat diameter of the first ejector (2) to the diameter of the first ejector inlet (2-1) is 1:2-1:

4.

4. The jet impact incineration fly ash ultra-fast water washing device according to claim 1 is characterized in that: The ratio of the throat diameter of the second ejector (3) to the diameter of the second ejector inlet (3-1) is 1:2-1:

4.

5. The jet impact incineration fly ash ultra-fast water washing device according to claim 1 is characterized in that: The feed pipe (6) and the return pipe (10) are arranged to be inclined, with an angle with the horizontal direction being not less than 30°.

6. The jet impact incineration fly ash ultra-fast water washing device according to claim 1 is characterized in that: The smoke pressurizing unit (1) is an air pump.

7. A water washing method based on the jet impact incineration fly ash ultra-fast water washing device according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. The flue gas is pressurized to 0.3-0.8 MPa by the flue gas pressurizing unit (1) and then injected into the first ejector (2). The negative pressure at the throat of the first ejector (2) inhales carbon dioxide and mixes it with the flue gas. The concentration of carbon dioxide in the mixed flue gas is ≥20%; S2. The mixed flue gas ejected by the first ejector enters the throat of the second ejector (3) through the inlet (3-1) of the second ejector, and the throat uses negative pressure to suck the fly ash slurry in the pre-slurry tank, and the fly ash slurry mixes with the mixed flue gas to form a high-speed gas-liquid two-phase mixed jet; S3. The gas-liquid two-phase mixed jet ejected by the second ejector impacts the impact tank (8) from above the liquid surface of the impact tank to achieve turbulence enhancement to further break up the fly ash particles in the fly ash slurry; S4. The flue gas in the impact tank returns to the incineration system after gas-liquid separation, and the liquid returns to the impact tank through the return pipe; S5. The slurry after washing is dehydrated, the fly ash is recycled, and the filtrate is discharged for reprocessing.

8. The water washing method of the jet impact incineration fly ash ultra-fast water washing device according to claim 7 is characterized in that: The gas-liquid volume ratio of the mixed flue gas to the fly ash slurry in step S2 is 1:5-1:10, and the pH value of the slurry after mixing is less than 7.

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