Fly ash washing treatment system

Abstract

The utility model relates to a fly ash washing treatment system. The fly ash washing treatment system comprises a washing unit and a separating unit, the washing unit is used for stirring and mixing fly ash and water into fly ash slurry; the separation unit is connected with the washing unit to separate the fly ash slurry to obtain washing fly ash and washing liquid, the separation unit is provided with a washing fly ash outlet and a washing liquid outlet, and the washing fly ash outlet is connected with a washing fly ash treatment unit used for treating dioxin and solidified heavy metal in the washing fly ash; and the water washing liquid outlet is connected with a water washing liquid treatment unit for treating heavy metals, organic matters, sodium chloride and potassium chloride in the water washing liquid. When the fly ash washing treatment system disclosed by the utility model is used, harmless treatment and resource utilization of fly ash washing products are synchronously realized.

Description

Technical Field

[0001] The utility model relates to the technical field of fly ash treatment, in particular to a fly ash water washing disposal system. Background Art

[0002] With the continuous improvement of people's living standards and environmental awareness, the amount of urban domestic waste is increasing day by day, and the pollution caused by the incineration of domestic waste has attracted widespread attention from the society. As a hazardous waste, the harmless disposal and resource utilization of fly ash produced by the incineration of domestic waste has become a research hotspot.

[0003] The harmless and resource-based disposal methods of fly ash include solidification and stabilization, water washing, heat treatment, etc. Among them, water washing is widely used because it can extract soluble salts in fly ash for the preparation of industrial salt and realize the resource utilization of fly ash. However, pollutants such as dioxins and heavy metals in the washed fly ash and washing liquid still need to be further removed to achieve the harmless disposal of fly ash treatment products. Most of the current fly ash disposal technologies are limited to the removal of pollutants in the washed fly ash or washing liquid, such as thermal desorption to remove dioxins, adding agents to the washing liquid to solidify heavy metals, etc., but the existing technology cannot remove pollutants in the washed fly ash and washing liquid. Utility Model Content

[0004] The utility model provides a fly ash water washing disposal system to solve the technical problem in the prior art that pollutants in the fly ash and the washing liquid after water washing are difficult to be removed synchronously, thus reducing the efficiency.

[0005] In order to solve the above problems, the utility model provides a fly ash washing disposal system adopting the following technical solutions:

[0006] A fly ash water washing disposal system comprises a water washing unit and a separation unit;

[0007] The water washing unit is used to stir and mix fly ash and water into fly ash slurry; the separation unit is connected to the water washing unit to separate the fly ash slurry to obtain washed fly ash and washing liquid, the separation unit has a washed fly ash outlet and a washing liquid outlet, the washed fly ash outlet is connected to a washed fly ash treatment unit for treating dioxins and solidified heavy metals in the washed fly ash; the washing liquid outlet is connected to a washing liquid treatment unit for treating heavy metals, organic matter, sodium chloride and potassium chloride in the washing liquid.

[0008] The beneficial effect is as follows: when the fly ash washing disposal system of the utility model is used, firstly, fly ash is added into the washing unit to obtain fly ash slurry, the fly ash slurry enters the separation unit to separate into washed fly ash and washing liquid, the washed fly ash enters the washed fly ash disposal unit for treatment; the washing liquid enters the washing liquid treatment unit for treatment. When the fly ash washing disposal system of the utility model is used, firstly, the fly ash slurry is separated into washed fly ash and washing liquid by the separation unit, and then the washed fly ash treatment unit and the washing liquid treatment unit are made to work simultaneously to treat the washed fly ash and the washing liquid respectively.

[0009] Furthermore, the washed fly ash disposal unit includes a hydrothermal degradation unit connected to the washed fly ash outlet and a solid-liquid separator connected to the hydrothermal degradation unit, wherein the hydrothermal degradation unit is used to mix the washed fly ash, inorganic alkali and hydrogen peroxide and heat and pressurize them to remove dioxins and solidified heavy metals in the washed fly ash; the solid-liquid separator is used to separate the washed fly ash into tailings and filtrate.

[0010] Beneficial effects: The structure is simple and the tailings can be easily collected and reused.

[0011] Furthermore, the water washing liquid disposal unit includes a precipitation regulating unit, an electrochemical deep purification unit and an evaporation crystallization salt separation unit which are connected in sequence, wherein the precipitation regulating unit is used to precipitate and separate calcium, magnesium and heavy metal ions in the water washing liquid; the electrochemical deep purification unit is used to reduce heavy metals into heavy metal elements and oxidize organic matter into carbon dioxide and water; the evaporation crystallization salt separation unit is used to separate sodium chloride crystals and potassium chloride crystals in the water washing liquid.

[0012] Beneficial effects: The structure is simple, and it is convenient for separating sodium chloride crystals and potassium chloride crystals, as well as for harmless disposal and resource utilization of fly ash washing liquid.

[0013] Furthermore, the precipitation adjustment unit is connected to the hydrothermal degradation unit to transport the generated precipitation into the hydrothermal degradation unit.

[0014] Beneficial effects: Improve the fly ash treatment rate and achieve harmless disposal and resource utilization of fly ash water washing liquid.

[0015] Furthermore, the water washing unit is a multi-stage water washing unit.

[0016] Beneficial effects: Improve the water washing quality, make the soluble salts in the fly ash fully dissolved in water and completely separated from the fly ash.

[0017] Furthermore, the water washing unit includes a primary water washing unit, a secondary water washing unit and a tertiary water washing unit, and the discharge ends of the primary water washing unit, the secondary water washing unit and the tertiary water washing unit are all connected with a separation unit, the separation unit at the discharge end of the secondary water washing unit is connected to the primary water washing unit through a first return water pipe to transport the filtrate precipitated by the separation unit at the discharge end of the secondary water washing unit to the primary water washing unit; the separation unit connected to the discharge end of the tertiary water washing unit is connected to the secondary water washing unit through a second return water pipe to transport the filtrate precipitated by the separation unit at the discharge end of the tertiary water washing unit to the secondary water washing unit.

[0018] Beneficial effects: Multi-stage water washing can completely extract the soluble salts in the fly ash, and the cascade utilization of the washing liquid can effectively save the water consumption for fly ash washing.

[0019] Furthermore, the solid-liquid separator is connected to the tertiary water washing unit to transport the separated filtrate to the tertiary water washing unit.

[0020] Beneficial effect: Improve the utilization rate of water resources.

[0021] Furthermore, the evaporation crystallization salt separation unit is connected to the tertiary water washing unit to transport the condensed water after crystallization in the evaporation crystallization salt separation unit to the tertiary water washing unit.

[0022] Beneficial effect: Improve the utilization rate of water resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present invention will become easy to understand. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0024] Figure 1 This is a flow chart of a fly ash water washing disposal system of the utility model;

[0025] Figure 2 It is a structural schematic diagram of the water washing unit of the utility model.

[0026] Description of reference numerals:

[0027] 1. Water washing unit; 2. Separation unit; 3. Hydrothermal degradation unit; 4. Solid-liquid separator; 5. Sedimentation adjustment unit; 6. Electrochemical deep purification unit; 7. Evaporation crystallization salt separation unit; 8. First return water pipe; 9. Second return water pipe. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Those skilled in the art should know that the embodiments described below are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0029] Any number of elements in the drawings is for illustration and not limitation, and any naming is for distinction only and does not have any limiting meaning.

[0030] The principle and spirit of the present invention are explained in detail below with reference to several representative embodiments of the present invention.

[0031] Embodiment 1 of a fly ash water washing disposal system provided by the utility model:

[0032] like Figure 1 As shown, a fly ash water washing disposal system of the utility model includes a water washing unit 1 and a separation unit 2.

[0033] like Figure 2 As shown, the water washing unit 1 is a multi-stage water washing unit 1 and includes a primary water washing unit 1, a secondary water washing unit 1 and a tertiary water washing unit 1, and the discharge ends of the primary water washing unit 1, the secondary water washing unit 1 and the tertiary water washing unit 1 are all connected with a separation unit, and the primary water washing unit 1, the secondary water washing unit 1 and the tertiary water washing unit 1 are all water washing tanks, and a stirrer is provided in the water washing tank to stir and mix the fly ash and water added to the water washing tank to obtain fly ash slurry. The discharge port of the separation unit 2 connected to the discharge end of the primary water washing unit 1 is connected to the secondary water washing unit 1, and the separation unit 2 connected to the discharge end of the secondary water washing unit 1 is connected to the tertiary water washing unit 1.

[0034] The separation unit at the discharge end of the secondary water washing unit 1 is connected to the primary water washing unit 1 through a first return pipe 8 to transport the filtrate precipitated by the separation unit at the discharge end of the secondary water washing unit 1 to the primary water washing unit 1; the separation unit connected to the discharge end of the tertiary water washing unit 1 is connected to the secondary water washing unit 1 through a second return pipe 9 to transport the filtrate precipitated by the separation unit at the discharge end of the tertiary water washing unit 1 to the secondary water washing unit 1.

[0035] The separation unit 2 connected to the tertiary water washing unit 1 is used to separate the fly ash slurry to obtain washed fly ash and water washing liquid. The discharge end of the separation unit 2 connected to the tertiary water washing unit 1 is also connected to the hydrothermal degradation unit 3; the discharge end of the separation unit 2 connected to the primary water washing unit 1 is also connected to the precipitation adjustment unit 5.

[0036] In this embodiment, the separation unit 2 is a filter press.

[0037] The washed fly ash enters the hydrothermal degradation unit 3 after coming out of the separation unit 2 connected to the tertiary washing unit 1. The hydrothermal degradation unit 3 removes dioxins and solidified heavy metals in the washed fly ash by hydrothermal degradation. When in use, firstly, inorganic alkali and hydrogen peroxide and other additives are added to the hydrothermal degradation unit 3, and then the dioxins and solidified heavy metals in the fly ash are removed under supercritical high temperature and high pressure conditions at a hydrothermal degradation temperature of 220°C and a hydrothermal degradation time of 2h. The discharge end of the hydrothermal degradation unit 3 is also connected to a solid-liquid separator 4.

[0038] The solid-liquid separator 4 is a filter press. The washed fly ash from which dioxins and solidified heavy metals are removed by the hydrothermal degradation unit 3 enters the solid-liquid separator 4 to separate tailings and filtrate for brick making. The discharge port of the filtrate on the solid-liquid separator 4 is connected to the tertiary water washing unit 1 to achieve the reuse of the filtrate, protect the environment and reduce the consumption of water resources.

[0039] The washing liquid separated from the discharge end of the separation unit 2 connected to the above-mentioned primary washing unit 1 enters the sedimentation adjustment unit 5, and the sedimentation adjustment unit includes a sedimentation tank. After the washing liquid enters the sedimentation tank, sodium carbonate reagent is added to the sedimentation tank. Sodium carbonate forms a precipitate with calcium, magnesium and heavy metal ions in the washing liquid. The precipitate produced after filtration is transported to the hydrothermal degradation unit 3.

[0040] After the precipitate is discharged, hydrochloric acid is introduced into the sedimentation tank to adjust the pH to 7.5 and filter. The discharge end of the sedimentation tank is also connected to an electrochemical deep purification unit 6.

[0041] The washing liquid after pH adjustment by hydrochloric acid enters the electrochemical deep purification unit 6, which includes an electrochemical cell, and a cathode current is passed through the electrochemical cell, so that under the electrochemical action, the heavy metals in the washing liquid are reduced at the cathode to generate heavy metal elements, and the organic matter in the washing liquid is oxidized to carbon dioxide and water, so as to achieve deep purification of residual heavy metals and organic matter in the washing liquid. The discharge end of the electrochemical deep purification unit 6 is connected to the evaporation crystallization salt separation unit 7.

[0042] The evaporation crystallization salt separation unit 7 includes an MVR evaporator. The MVR evaporator utilizes the difference in solubility of sodium chloride and potassium chloride with temperature to obtain sodium chloride crystalline salt by first evaporating the water washing liquid, and then cools the separated water washing liquid to obtain potassium chloride crystalline salt. The condensed water collected during the cooling process is reused in the above-mentioned three-stage water washing unit 1.

[0043] The utility model discloses a fly ash washing treatment system. When in use, firstly, fly ash is added into a washing tank of a washing unit 1 and stirred to obtain fly ash slurry. The fly ash slurry enters a separation unit 2 and is separated by a filter press to obtain washed fly ash and washing liquid. The washed fly ash enters a hydrothermal degradation unit 3. The washed fly ash is mixed with an inorganic alkali and hydrogen peroxide and heated and pressurized to remove dioxins and solidified heavy metals in the washed fly ash. The washed fly ash then enters a solid-liquid separator 4. The separated tailings can be used for brick making, pottery making or cement mixed materials. The washing liquid simultaneously enters a precipitation adjustment unit 5. Sodium carbonate, sodium phosphate or sulfuric acid is added into the precipitation tank to obtain the washed fly ash and washing liquid. Sodium, sodium carbonate or sodium phosphate or sodium sulfate forms a precipitate with calcium, magnesium and heavy metal ions in the washing liquid. After filtering and adjusting the pH, the washing liquid continues to enter the electrochemical cell in the electrochemical deep purification unit 6. The electrochemical cell reduces the heavy metals in the washing liquid at the cathode to generate heavy metal elements through electrochemical action, and the organic matter in the washing liquid is oxidized into carbon dioxide and water, thereby deeply purifying the residual heavy metals and organic matter in the washing liquid; the purified washing liquid enters the evaporator, first evaporates the washing liquid to obtain sodium chloride crystalline salt, and then cools the separated washing liquid to obtain potassium chloride crystalline salt, and the sodium chloride and potassium chloride can be used in industry.

[0044] When the utility model is used, the fly ash washing treatment system first removes dioxins and solidifies heavy metals in the washed fly ash through the hydrothermal degradation unit, and the separated tailings can also be used for brick making, pottery making or cement mixed materials; at the same time, the calcium, magnesium and heavy metal ions in the washing liquid are precipitated through the precipitation adjustment unit, and then the heavy metals and ions in the washing liquid are separated through the electrochemical deep purification unit, and finally the sodium chloride and potassium chloride in the washing liquid are separated through the evaporation crystallization salt separation unit for use in other industries. The harmless disposal and resource utilization of the fly ash washing products are realized simultaneously.

[0045] Embodiment 2 of a fly ash water washing disposal system provided by the utility model:

[0046] The main difference between it and Example 1 is that in Example 1, the separation unit is a filter press.

[0047] In this embodiment, the separation unit is a horizontal screw centrifuge or a vertical centrifuge.

[0048] Embodiment 3 of a fly ash water washing disposal system provided by the utility model:

[0049] The main difference between it and Example 1 is that in Example 1, the hydrothermal degradation temperature is 220° C., the hydrothermal degradation time is 2 h, and the separated tailings are used for brick making.

[0050] In this embodiment, the hydrothermal degradation temperature is 250° C., the hydrothermal degradation time is 3 hours, and the separated tailings are used as cement admixture.

[0051] Embodiment 4 of a fly ash water washing disposal system provided by the utility model:

[0052] The main difference between it and Example 1 is that in Example 1, hydrochloric acid is added to the water-heat thermal degradation unit to adjust the pH to 7.5, and an MVR evaporator is used to obtain sodium chloride crystal salt and potassium chloride crystal salt.

[0053] In this embodiment, hydrochloric acid is added to the water-heat thermal degradation unit to adjust the pH to 8, and a multiple-effect evaporator is used to obtain sodium chloride crystal salt and potassium chloride crystal salt.

[0054] Embodiment 5 of a fly ash water washing disposal system provided by the utility model:

[0055] The main difference between it and Example 1 is that in Example 1, the water washing unit is a water washing tank.

[0056] In this embodiment, the water washing unit is a water washing tank.

Claims

1. A fly ash washing treatment system, characterized in that: It includes a water washing unit and a separation unit; The water washing unit is used to stir and mix the fly ash and water into a fly ash slurry; the separation unit is connected to the water washing unit to separate the fly ash slurry to obtain washed fly ash and a washing liquid, the separation unit has a washed fly ash outlet and a washing liquid outlet, and the washed fly ash outlet is connected to a washed fly ash treatment unit for treating dioxins and solidified heavy metals in the washed fly ash; The washing liquid outlet is connected to a washing liquid treatment unit for treating heavy metals, organic matter, sodium chloride and potassium chloride in the washing liquid.

2. A fly ash washing disposal system according to claim 1, characterized in that: The washed fly ash disposal unit includes a hydrothermal degradation unit connected to the washed fly ash outlet and a solid-liquid separator connected to the hydrothermal degradation unit. The hydrothermal degradation unit is used to mix the washed fly ash, inorganic alkali and hydrogen peroxide and heat and pressurize them to remove dioxins and solidified heavy metals in the washed fly ash; the solid-liquid separator is used to separate the washed fly ash into tailings and filtrate.

3. A fly ash washing disposal system according to claim 2, characterized in that: The water washing liquid disposal unit includes a precipitation regulating unit, an electrochemical deep purification unit and an evaporation crystallization salt separation unit which are connected in sequence. The precipitation regulating unit is used to precipitate and separate calcium, magnesium and heavy metal ions in the water washing liquid; the electrochemical deep purification unit is used to reduce heavy metals into heavy metal elements and oxidize organic matter into carbon dioxide and water; the evaporation crystallization salt separation unit is used to separate sodium chloride crystals and potassium chloride crystals in the water washing liquid.

4. A fly ash washing disposal system according to claim 3, characterized in that: The precipitation adjustment unit is connected to the hydrothermal degradation unit to transport the generated precipitation into the hydrothermal degradation unit.

5. A fly ash washing disposal system according to claim 4, characterized in that: The water washing unit is a multi-stage water washing unit.

6. A fly ash washing disposal system according to claim 5, characterized in that: The water washing unit comprises a primary water washing unit, a secondary water washing unit and a tertiary water washing unit, and the discharge ends of the primary water washing unit, the secondary water washing unit and the tertiary water washing unit are all connected with a separation unit, and the separation unit at the discharge end of the secondary water washing unit is connected to the primary water washing unit through a first return pipe, so as to transport the filtrate precipitated by the separation unit at the discharge end of the secondary water washing unit to the primary water washing unit; The separation unit connected to the discharge end of the tertiary water washing unit is connected to the secondary water washing unit through a second return pipe to transport the filtrate precipitated from the separation unit at the discharge end of the tertiary water washing unit to the secondary water washing unit.

7. A fly ash washing disposal system according to claim 6, characterized in that: The solid-liquid separator is connected to the tertiary water washing unit to transport the separated filtrate to the tertiary water washing unit.

8. A fly ash washing disposal system according to claim 6, characterized in that: The evaporation crystallization salt separation unit is connected to the tertiary water washing unit to transport the condensed water after crystallization in the evaporation crystallization salt separation unit to the tertiary water washing unit.

Images