Integrated device and method for efficiently reducing hardness of fly ash washing liquid

Abstract

The invention discloses an integrated device and method for efficiently reducing the hardness of fly ash water washing liquid. The integrated device comprises a box body, a pH detection unit, a dosing unit and an aeration unit, a top cover is arranged above the box body, and the box body comprises a reaction chamber, a first water producing chamber and a second water producing chamber; the two sides of the reaction chamber are provided with a weir plate mechanism and an overflowing channel, an overflowing opening is reserved between the top of the two side walls of the reaction chamber and the top cover, the reaction chamber is communicated with the first water production chamber and the second water production chamber through the overflowing opening and the overflowing channel respectively, and the weir plate mechanism realizes disconnection and communication of the overflowing channel through lifting of an adjustable weir plate; a water inlet and a dosing port are formed in the side surface of the reaction chamber, a water outlet is formed in the bottom, and a three-phase mixer is arranged in the reaction chamber; the first water producing chamber and the second water producing chamber are provided with produced water outlets, and sludge openings are formed in the bottoms of the first water producing chamber and the second water producing chamber; pH detection units are arranged in produced water outlets of the first produced water chamber and the second produced water chamber and the overflowing channel. The device is easy to operate and convenient to maintain, and the hardness of the fly ash washing liquid can be efficiently reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and more specifically, to an integrated device and method for efficiently reducing the hardness of fly ash washing liquid. Background Art

[0002] With the continuous improvement of economic development and living standards, urban waste treatment faces great challenges. Incineration is one of the important means of waste treatment at present. However, a large amount of fly ash is generated during the incineration process. The fly ash contains organic pollutants such as benzo[a]pyrene, benzo[a]anthracene, and dioxins, as well as heavy metals such as Cr, Cd, Hg, Pb, and Cu, Ni. It is a highly dangerous solid waste with a large output. In recent years, the disposal problem of fly ash has received extensive attention. At present, it is mainly to prepare building materials by high-temperature sintering of fly ash. However, due to the large amount of soluble chlorides in fly ash, which affects the product quality, the washing method is mostly used to reduce the chlorine element content in fly ash.

[0003] Fly ash washing liquid is a strong alkaline solution with relatively high concentrations of heavy metals and salts. Direct discharge not only seriously pollutes the environment but also causes waste of resources. At present, the industrial method mainly adopts evaporation crystallization to recover a large amount of potassium salts and sodium salts in the solution. In order to make the salt products have higher purity, it is necessary to separate calcium from the fly ash washing liquid first. The current mainstream method for separating calcium ions in fly ash washing liquid is the sodium carbonate chemical precipitation method. However, this method has problems such as large storage area for sodium carbonate, complex reagent preparation, long reaction time required for powder addition, and the need for stirring equipment, which affects the reaction efficiency.

[0004] Chinese Patent Application No. 201510001918.2 discloses a device for removing hardness and lowering the pH value of fly ash washing liquid from waste incineration. By means of devices such as a stirring tank, a centrifuge, and a bubbling reactor, an alkali solution is added to generate calcium hydroxide precipitation, and carbon dioxide is introduced into the supernatant after centrifugation to achieve the purpose of reducing the hardness of fly ash washing liquid. This technology requires more operation units and complex operations, and has a relatively high upfront investment.

[0005] Chinese Patent Application No. 202111253789.8 discloses a process for coupling CO2 with alkali metal hydroxides to reduce the hardness of fly ash washing liquid. The purified CO2 is used to react with the alkali metal solution through the contact mode of aeration and spraying to generate carbonate ions, so as to achieve the purpose of reducing the hardness of fly ash washing liquid. Although this method uses CO2 aeration, the hardness of the washing liquid can only reach below 200 mg / L (calculated as CaO) after secondary treatment, which increases the equipment complexity and operating cost. Summary of the Invention

[0006] Aiming at the defects existing in the prior art, the purpose of the present invention is to provide an integrated device and method for efficiently reducing the hardness of fly ash washing liquid, which is simple to operate, convenient to maintain, has a small footprint and low operating energy consumption, and can efficiently remove the hardness of fly ash washing liquid.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect of the present invention, there is provided an integrated device for efficiently reducing the hardness of fly ash washing liquid, including a box body, a pH detection unit arranged in the box body, and a medicine adding unit and an aeration unit connected to the box body;

[0009] A top cover is provided above the box body, and an aeration connection port connected to the aeration unit is arranged on the top cover; the box body includes a reaction chamber, and a first water production chamber and a second water production chamber respectively arranged on both sides of the reaction chamber;

[0010] Weir plate mechanisms and overflow channels are arranged on both sides of the reaction chamber. There are overflow ports left between the top of the two side walls of the reaction chamber and the top cover. The reaction chamber is communicated with the first water production chamber and the second water production chamber respectively through the overflow ports and overflow channels on its two sides. The weir plate mechanism realizes the disconnection and connection of the overflow channel through the lifting of the adjustable weir plate; a water inlet connected to the fly ash washing liquid and a medicine adding port connected to the medicine adding unit are arranged on the side of the reaction chamber, and a drain port is arranged at the bottom of the reaction chamber. A three-phase mixer connected to the aeration unit is arranged in the reaction chamber;

[0011] Water production outlets are arranged on the sides of the first water production chamber and the second water production chamber, and sludge ports are arranged at the bottoms;

[0012] The pH detection unit is arranged in the water production outlets of the first water production chamber and the second water production chamber and in the overflow channel.

[0013] Preferably, the upper parts of the reaction chamber, the first water production chamber and the second water production chamber are of rectangular cylinder structures, and the lower parts are of frustum cylinder structures.

[0014] Preferably, the weir plate mechanism includes an adjustable weir plate and a lifting mechanism connected to the adjustable weir plate. The adjustable weir plate performs a lifting action along the side wall of the reaction chamber under the action of the lifting mechanism.

[0015] Preferably, a cleaning spray device is arranged at the top position of the overflow channel, and the cleaning spray device is connected to a flushing water bypass.

[0016] Preferably, the gas inlet of the three-phase mixer is connected to the aeration unit;

[0017] The three-phase mixer is provided with a nozzle and a plurality of mushroom heads with a hydraulic shearing function, and the material of the mushroom heads is selected from modified PP, ABS or PTFE.

[0018] Preferably, the three-phase mixer is arranged at the middle position of the bottom of the rectangular cylinder structure at the upper part of the reaction chamber, and the installation heights of the water inlet and the chemical dosing port are close to the installation height of the outlet of the three-phase mixer.

[0019] The second aspect of the present invention provides a method for efficiently reducing the hardness of fly ash washing liquid, which uses the integrated device for efficiently reducing the hardness of fly ash washing liquid as described in the first aspect of the present invention to perform the following steps:

[0020] S1. According to the water quality data of the fly ash washing liquid, the fly ash washing liquid and the alkali solution are simultaneously added into the reaction chamber, and then CO2 is introduced through the three-phase mixer for sufficient mixing reaction to obtain a suspension;

[0021] S2. Adjust the weir plate mechanism on one side of the reaction chamber, and the suspension in the reaction chamber overflows to the first water production chamber through the overflow channel on one side. When the volume of the suspension in the first water production chamber reaches the set liquid level, close the corresponding overflow channel, adjust the weir plate mechanism on the other side of the reaction chamber, and the suspension in the reaction chamber overflows into the second water production chamber until the volume of the suspension in the second water production chamber reaches the set liquid level;

[0022] S3. After the volumes of the suspensions in the first water production chamber and the second water production chamber reach the set liquid levels, let them stand. After solid-liquid separation, the upper-layer produced water is transported to the water production tank, and the lower-layer solid phase is discharged through the sludge outlet.

[0023] Preferably, in the step S1:

[0024] The pH of the fly ash washing liquid is 9-13, the calcium ion content is 5-20 g / L, and the magnesium ion content is 0.1-0.5 g / L;

[0025] The CO2 is selected from CO2 in the cement kiln tail gas, CO2 in the waste flue gas or industrial carbon dioxide, and its volume fraction ≥5%;

[0026] The mixing reaction time is 10-30 min.

[0027] Preferably, in the step S1, the alkali solution is selected as a sodium hydroxide solution;

[0028] When the pH of the fly ash washing liquid > 11.5, no alkali solution is introduced into the reaction chamber;

[0029] When the pH of the fly ash washing liquid ≤ 11.5, the addition amount of the alkali solution is as follows:

[0030]

[0031] Wherein, m NaOH is the mass of the lye, in g;

[0032] V is the volume of the fly ash washing liquid, in L;

[0033] pH 目标 is the target pH of the fly ash washing liquid, and its range is 11.5 to 12;

[0034] pH 初始 is the initial pH of the fly ash washing liquid;

[0035] [Mg 2+ is the concentration of Mg 2+ , in g / L;

[0036] [Ca 2+ is the concentration of Ca 2+ , in g / L.

[0037] Preferably, in the step S1, the introduction amount of the CO2 is as follows:

[0038]

[0039] Wherein, is the mass of the CO2, in g;

[0040] [Ca 2+ is the concentration of Ca 2+ , in g / L;

[0041] pH 反应前 is the pH of the fly ash washing liquid before reaction, and its range is 11.5 to 13;

[0042] pH 终点 is the pH at the end point of the produced water, and its range is 9.5 to 10.5;

[0043] V is the volume of the fly ash washing liquid, in L;

[0044] Preferably, in the step S3:

[0045] the standing time is 10 to 30 min;

[0046] in the step S3, the pH of the produced water is 9.5 to 10.5, the calcium ion content ≤ 45 mg / L, and the magnesium ion content ≤ 5 mg / L.

[0047] The effects of the present invention are as follows:

[0048] 1. The present invention can make full use of the carbon dioxide in the cement kiln tail gas and the waste flue gas, which can not only achieve the purpose of energy conservation and emission reduction, but also greatly reduce the treatment cost of the fly ash washing liquid;

[0049] 2. The operation of the present invention is simple, the maintenance is convenient, it can run continuously for a long time, and the time required for cleaning and maintenance due to equipment scaling is reduced;

[0050] 3. By utilizing the intense mixing of the three-phase mixer in the aeration unit of the integrated device, the gas containing CO2 is dispersed into nanoscale microbubbles in the fly ash washing liquid, increasing the gas-liquid contact area. The carbon dioxide absorption efficiency can reach more than 90%. The equipment occupies a small area and has low operating energy consumption, which can reduce the system investment and operating energy consumption. Moreover, it has good hardness removal effect and high efficiency, and can remove 99% of calcium ions in the fly ash washing liquid. A cleaning spray device is provided in the integrated device, which can effectively prevent fouling caused by a large amount of sludge generated during the fly ash hardness removal process, is convenient for maintenance and has low cost. Alkali liquid and CO2 can completely replace sodium carbonate, greatly reducing the cost of removing hardness from the fly ash washing liquid. Brief Description of the Drawings

[0051] Figure 1 It is a schematic structural diagram of the integrated device for efficiently reducing the hardness of fly ash washing liquid of the present invention;

[0052] Figure 2 It is a bottom view of the integrated device for efficiently reducing the hardness of fly ash washing liquid of the present invention;

[0053] In the figure, 1. Box body; 2. Reaction chamber; 3. First water production chamber; 4. Second water production chamber; 5. Water outlet of the first water production chamber; 6. Water outlet of the second water production chamber; 7. Three-phase mixer; 8. Chemical addition port; 9. Water inlet; 10. Cleaning spray device; 11. Weir plate mechanism; 12. Sludge outlet of the first water production chamber; 13. Drainage port; 14. Sludge outlet of the second water production chamber; 15. Aeration connection port. Detailed Embodiments

[0054] In order to better understand the above technical solutions of the present invention, the technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0055] Combined with Figure 1 、 Figure 2As shown in the figure, an integrated device for efficiently reducing the hardness of fly ash washing liquid provided by the present invention includes a box body 1, a pH detection unit arranged in the box body 1, a dosing unit and an aeration unit connected to the box body 1. A top cover is provided above the box body 1, and an aeration connection port 15 connected to the aeration unit is provided on the top cover; the box body 1 includes a reaction chamber 2, a first water production chamber 3 and a second water production chamber 4 respectively arranged on both sides of the reaction chamber. Weir plate mechanisms 11 and overflow channels are arranged on both sides of the reaction chamber 2. An overflow port is left between the top of the two side walls of the reaction chamber 2 and the top cover. The reaction chamber 2 is communicated with the first water production chamber 3 and the second water production chamber 4 respectively through the overflow ports and overflow channels on both sides thereof. The weir plate mechanism 11 realizes the disconnection and connection of the overflow channel by the lifting of the adjustable weir plate; a water inlet 9 connected to the fly ash washing liquid and a dosing port 8 connected to the dosing unit are arranged on the side surface of the reaction chamber 2. A drain port 13 is arranged at the bottom of the reaction chamber 2. A three-phase mixer 7 connected to the aeration unit is arranged in the reaction chamber 2. Water production outlets 5 and 6 are arranged on the side surfaces of the first water production chamber 3 and the second water production chamber 4 respectively, and sludge ports 12 and 14 are arranged at the bottoms. pH detection units are arranged in the water production outlets of the first water production chamber 3 and the second water production chamber 4 and in the overflow channels.

[0056] As shown in the structural schematic diagram, the upper parts of the reaction chamber 2, the first water production chamber 3 and the second water production chamber 4 are rectangular cylinder structures, and the lower parts are frustum cylinder structures. A water inlet pump is arranged on the water inlet pipe between the water inlet 9 of the reaction chamber 2 and the fly ash washing liquid, and a metering pump is arranged on the dosing pipe of the dosing port 8 and the dosing unit. The water production outlets of the first water production chamber 3 and the second water production chamber 4 are connected to a water production tank or other buffer devices or subsequent treatment devices through water production pipes, and a water production pump is arranged on the water production pipes. The sludge ports of the first water production chamber 3 and the second water production chamber 4 discharge sludge through sludge pipes, and a sludge pump is arranged on the sludge pipes.

[0057] Combined with Figure 1 As shown in the figure, the weir plate mechanism 11 includes an adjustable weir plate and a lifting mechanism connected to the adjustable weir plate. The adjustable weir plate performs a lifting action along the side wall of the reaction chamber under the action of the lifting mechanism. When the adjustable weir plate rises to the top cover under the action of the lifting mechanism, the overflow channel is disconnected, and the reaction chamber 2 is separated from the first water production chamber 3 or the second water production chamber 4; when the adjustable weir plate descends, the reaction chamber 2 is communicated with the first water production chamber 3 or the second water production chamber 4 through the overflow port and the overflow channel.

[0058] Combined with Figure 1 As shown in the figure, a cleaning spray device 10 is arranged at the top position of the overflow channel, and the cleaning spray device is connected to a flushing water bypass. In this way, a large flow of flushing water can be used to discharge the sludge remaining in the overflow channel, effectively preventing blockage caused by a large amount of sludge generated during the fly ash hardness removal process.

[0059] As shown in Figure 1, the gas inlet of the three-phase mixer 7 is connected to the aeration unit; a nozzle and multiple mushroom heads with hydraulic shearing function are provided inside the three-phase mixer 7, and the material of the mushroom heads is selected from modified PP, ABS or PTFE. In a specific embodiment, the three-phase mixer 7 is arranged at the middle position of the bottom of the upper rectangular cylinder structure of the reaction chamber 2, and the installation heights of the water inlet 9 and the chemical dosing port 8 are close to the installation height of the outlet of the three-phase mixer 7.

[0060] Combined with Figure 1 As shown, the aeration unit is arranged above the top cover, and the aeration unit is connected to the three-phase mixer 7 through an aeration pipe penetrating the top cover. The aeration unit transports the gas containing CO2 into the three-phase mixer through the aeration pipe.

[0061] The above device integrates a cleaning spray device 10, the sludge fouling rate is reduced by 80%, and the device occupies a small area, has low operating energy consumption, is simple to operate and convenient to maintain, and can reduce the investment and maintenance costs.

[0062] The present invention also provides a method for efficiently reducing the hardness of fly ash washing liquid. Through the nano-scale microbubble aeration technology of the three-phase mixer 7, the reaction of sodium hydroxide and CO2 is coupled to completely replace sodium carbonate. The calcium ion content in the fly ash washing liquid can be reduced to less than 45 mg / L and the magnesium ion content can be reduced to less than 5 mg / L in a single treatment, the calcium removal rate is ≥99%, and the CO2 absorption rate is ≥90%; the present invention can make full use of the carbon dioxide in the cement kiln tail gas and waste flue gas, which can not only achieve the purpose of energy conservation and emission reduction, but also greatly reduce the treatment cost of the fly ash washing liquid.

[0063] The following steps are performed using the above integrated device for efficiently reducing the hardness of fly ash washing liquid:

[0064] S1. According to the water quality data of the fly ash washing liquid, the fly ash washing liquid and the alkali solution are simultaneously added into the reaction chamber 2, and then CO2 is introduced through the three-phase mixer 7 for sufficient mixing reaction to obtain a suspension;

[0065] In this step, the pH of the fly ash washing liquid used is 9 - 13, the calcium ion content is 5 - 20 g / L, and the magnesium ion content is 0.1 - 0.5 g / L. CO2 can be selected from cement kiln tail gas, waste flue gas or industrial carbon dioxide, and the volume percentage of CO2 is ≥5%, such as 5 - 99.9%; if cement kiln tail gas or waste flue gas is selected, the volume percentage content of carbon dioxide in it is ≥5%, such as 5% - 30%; higher purity industrial carbon dioxide (its volume percentage can be 99.9%) can also be used. The alkali solution can be selected as sodium hydroxide solution.

[0066] In this step, according to the water quality data of the fly ash washing liquid, the fly ash washing liquid and the alkali solution are added to the reaction chamber 2 simultaneously. When the pH of the fly ash washing liquid > 11.5, no alkali solution is introduced into the reaction chamber 11; when the pH of the fly ash washing liquid ≤ 11.5, the addition amount of the alkali solution is as follows:

[0067]

[0068] where m NaOH is the mass of the alkali solution, in g;

[0069] V is the volume of the fly ash washing liquid, in L;

[0070] pH 目标 is the target pH of the fly ash washing liquid, with a range of 11.5 - 12;

[0071] pH 初始 is the initial pH of the fly ash washing liquid;

[0072] [Mg 2+ is the concentration of Mg 2+ , in g / L;

[0073] [Ca 2+ is the concentration of Ca 2+ , in g / L.

[0074] After that, CO2 is introduced through the three-phase mixer 7 for sufficient mixing reaction to obtain a suspension. The mixing reaction time is 10 - 30 min; at this time, using the negative pressure locally generated in the three-phase mixer 7, the fly ash washing liquid (i.e., the liquid-solid mixture) is sucked into the nozzle of the three-phase mixer 7 and then sprayed upward under pressure. During the upward movement, it collides with the mushroom head, mixes violently, generates fine nanoscale small bubbles, and fully mixes the gas-liquid-solid three phases. In this way, the three phases in the reaction chamber 2 are kept in a suspension state without sedimentation and stratification.

[0075] The introduction amount of the above-mentioned CO2 is as follows:

[0076]

[0077] where is the mass of CO2, in g;

[0078] [Ca 2+ is the concentration of Ca 2+ , in g / L;

[0079] pH 反应前 is the pH of the fly ash washing liquid before the reaction, that is, when the pH of the fly ash washing liquid ≤ 11.5, it is the target pH adjusted by adding the alkali solution, or when the pH of the fly ash washing liquid > 11.5, it is the initial pH, with a range of 11.5 - 13;

[0080] pH 终点 is the pH at the end of water production, and its range is 9.5 to 10.5;

[0081] V is the volume of the fly ash washing liquid, and the unit is L.

[0082] S2. Adjust the weir plate mechanism 11 on one side of the reaction chamber 2. The suspension in the reaction chamber 2 overflows to the first water production chamber 3 through the overflow channel on one side. When the volume of the suspension in the first water production chamber 3 reaches the set liquid level, close the corresponding overflow channel, and adjust the weir plate mechanism 11 on the other side of the reaction chamber 2. The suspension in the reaction chamber 2 overflows into the second water production chamber 4 until the volume of the suspension in the second water production chamber 4 reaches the set liquid level;

[0083] In this step, after the suspension is formed in the reaction chamber 2, first adjust the weir plate mechanism 11 on the side close to the first water production chamber 3 to lower the adjustable weir plate, so that the overflow channel on the side close to the first water production chamber 3 is connected. The suspension in the reaction chamber 2 overflows into the first water production chamber 3 through the overflow port and the overflow channel. When the volume of the suspension in the first water production chamber 3 reaches the set liquid level, close the corresponding overflow channel, and then adjust the weir plate mechanism 11 on the other side of the reaction chamber 2. The suspension in the reaction chamber 2 overflows into the second water production chamber 4 until the volume of the suspension in the second water production chamber 4 reaches the set liquid level;

[0084] S3. After the volumes of the suspensions in the first water production chamber 3 and the second water production chamber 4 reach the set liquid levels, let them stand. After solid-liquid separation, the upper layer of the produced water is transported to the water production tank, and the lower layer of the solid phase is discharged through the sludge outlet.

[0085] In this step, when the volume of the suspension in the first water production chamber 3 reaches the set liquid level, let it stand for 10 to 30 minutes. After solid-liquid separation, use a water production pump to transport the upper layer of the produced water in the first water production chamber 3 to the water production tank; similarly, when the volume of the suspension in the second water production chamber 4 reaches the set liquid level, let it stand for 10 to 30 minutes. After solid-liquid separation, use a water production pump to transport the upper layer of the produced water in the second water production chamber 4 to the water production tank. The solid phase in the lower layers of the first water production chamber 3 and the second water production chamber 4 is discharged through the bottom sludge outlets 12 and 14, and the sludge remaining in the overflow channel can be flushed by the cleaning spray device 10 to avoid sludge blockage of the overflow channel.

[0086] After the above treatment, the pH of the produced water is 9.5 to 10.5, the calcium ion content ≤ 45 mg / L, and the magnesium ion content ≤ 5 mg / L; by the above method, the calcium ion and magnesium ion contents in the produced water are effectively reduced, thereby reducing the hardness of the produced water.

[0087] Example 1

[0088] As shown in the reference structure diagram, this embodiment provides an integrated device for efficiently reducing the hardness of fly ash washing liquid, which includes a box body 1, a pH detection unit arranged in the box body 1, and a dosing unit and an aeration unit connected to the box body 1. A top cover is provided above the box body 1, and the box body 1 includes a reaction chamber 2, a first water production chamber 3 and a second water production chamber 4 respectively arranged on both sides of the reaction chamber 2. The upper parts of the reaction chamber 2, the first water production chamber 3 and the second water production chamber 4 are of rectangular cylinder structure, and the lower parts are of frustum cylinder structure.

[0089] Weir plate mechanisms 11 and overflow channels are arranged on both sides of the reaction chamber 2, and overflow ports are left between the tops of the two side walls of the reaction chamber 2 and the top cover; the reaction chamber 2 is communicated with the water production chambers 3 and 4 through the overflow ports and overflow channels on both sides. The weir plate mechanism 11 includes an adjustable weir plate and a lifting mechanism. The three-phase mixer 7 is arranged at the middle position of the bottom of the upper rectangular cylinder structure of the reaction chamber 2, and the three-phase mixer 7 is communicated with the air supply pipe of the aeration unit (which penetrates through the top cover and is connected to the air supply pipe), and a gas containing CO2 is introduced through the air supply pipe. A gas flow meter and a pressure gauge are provided at the inlet of the air supply pipe; a nozzle and a plurality of mushroom heads with hydraulic shearing function are arranged inside the three-phase mixer 7. An inlet 9 and a dosing port 8 are arranged on the side of the reaction chamber 2. The fly ash washing liquid is injected into the reaction chamber 2 through the inlet pipe and the inlet water pump via the inlet 9. A rotor flow meter and a pressure gauge are arranged on the inlet pipe; the sodium hydroxide solution is injected through the metering pump and the dosing pipe via the dosing port 8. The installation heights of the dosing port 9 and the inlet 8 are close to the outlet height of the three-phase mixer 7. A cleaning spray device 10 is connected to the top position of the overflow channel. The cleaning spray device 10 is connected to the flushing water bypass and can pass a large flow of flushing water to discharge the sludge remaining in the overflow channel.

[0090] Water production outlets 5 and 6 are arranged on the sides of the first water production chamber 3 and the second water production chamber 4 respectively. The produced water is transported to the water production tank or subsequent treatment device through the water production pump; sludge outlets 12 and 14 are arranged at the bottoms of the first water production chamber 3 and the second water production chamber 4 respectively. The sludge outlets are connected with pneumatic diaphragm pumps as sludge pumps to discharge the sludge.

[0091] The pH detection unit is respectively arranged at the middle position of the overflow channel and at the water production outlets of the first water production chamber 3 and the second water production chamber 4.

[0092] This embodiment utilizes Figure 1 、 Figure 2 The integrated device shown in the figure for efficiently reducing the hardness of fly ash washing liquid to treat the fly ash washing liquid, and the specific process is as follows:

[0093] (1) Initial water quality conditions: The pH of the fly ash washing liquid is 11.2, the calcium ion content is 14.5 g / L, and the magnesium ion content is 0.023 g / L; the alkali solution selects a sodium hydroxide solution with a mass fraction of 48%, and the CO2 selects industrial carbon dioxide with a purity of 99.9%.

[0094] (2) Calculated amount of lye addition: According to formula (a), the target pH of the fly ash washing liquid is controlled at 11.5, and the initial pH is 11.2. Substitute into the formula to calculate the amount of sodium hydroxide addition. The calculated amount is 29 kg of sodium hydroxide per cubic meter of fly ash washing liquid. Using a sodium hydroxide solution with a mass fraction of 48%, so 60.4 kg of 48% sodium hydroxide solution is required per cubic meter of fly ash washing liquid.

[0095] (3) CO2 addition calculation: The target pH of the produced water is 10.5. According to formula (b), the calculation result is that 15.95 kg of CO2 needs to be introduced per cubic meter of fly ash washing liquid. Using carbon dioxide with a volume fraction of ≥99.5%, so 16 kg of carbon dioxide is required per cubic meter of fly ash washing liquid.

[0096] (4) According to the water quality data of the fly ash washing liquid, add the fly ash washing liquid and lye into the reaction chamber simultaneously, and then introduce CO2 through a three-phase mixer. Utilize the local negative pressure generated in the three-phase separator to suck the liquid-solid mixture into the nozzle and then spray it upward under pressure. During the rising process, it collides with the mushroom head and mixes violently to generate fine nano-scale small bubbles, and fully mix and react the gas-liquid-solid three phases for 30 minutes, keeping the three phases in the reaction chamber in a suspension state without sedimentation and stratification to form a suspension.

[0097] (5) Adjust the weir plate mechanism near the first water production chamber side to make the suspension in the reaction chamber flow into the first water production chamber through the flow channel. When the volume of the suspension in the first water production chamber reaches the set liquid level, close the flow channel on the first water production chamber side. The suspension in the first water production chamber is allowed to stand for 30 minutes. After solid-liquid separation, use a water production pump to transport the produced water to the water production tank for storage.

[0098] (6) When the volume of the suspension in the first water production chamber reaches the set liquid level, adjust the weir plate mechanism near the second water production chamber side to make the suspension in the reaction chamber flow into the second water production chamber through the flow channel until the volume of the suspension inside reaches the set liquid level. The suspension in the second water production chamber is allowed to stand for 30 minutes. After solid-liquid separation, use a water production pump to transport the produced water to the water production tank for storage.

[0099] (5) The sludge at the bottom of the above-mentioned first water production chamber and second water production chamber is discharged from the sludge outlet. A cleaning spray device can be used to wash the residual sludge in the flow channel to avoid sludge blockage of the flow channel.

[0100] The pH of the produced water in this embodiment is 10.12, the calcium ion concentration is 32.5 mg / L, the magnesium ion content is 0.22 mg / L, the removal rate of calcium ions can reach 99.7%, and according to the water quality detection data, the carbon dioxide absorption efficiency is 91.12%.

[0101] Example 2

[0102] This embodiment adopts Figure 1 and Figure 2 the integrated device for efficiently reducing the hardness of fly ash washing liquid shown in the figure to treat the fly ash washing liquid. The specific process is as follows:

[0103] (1) Initial water quality conditions: The pH of the fly ash washing liquid is 10.8, the calcium ion content is 8.2 g / L, and the magnesium ion content is 0.3 g / L; the alkali solution is a sodium hydroxide solution with a mass fraction of 30%, and the cement kiln tail gas with a CO2 volume fraction of 30% is used.

[0104] (2) Calculated dosage of alkali solution addition: According to formula (a), control the target pH of the fly ash washing liquid to be 11.5 and the initial pH to be 10.8. Substitute into the formula to calculate the dosage of sodium hydroxide addition. The calculated dosage is 17.4 kg of sodium hydroxide per cubic meter of fly ash washing liquid. Since a sodium hydroxide solution with a mass fraction of 30% is used, 58 kg of 30% sodium hydroxide solution is required per cubic meter of fly ash washing liquid.

[0105] (3) CO2 addition calculation: The target pH of the produced water is 9.8. According to formula (b), the calculation result is that 9.02 kg of CO2 needs to be introduced per cubic meter of fly ash washing liquid. The CO2 concentration in the cement kiln tail gas is 30%, so 15.3 m 3 of cement kiln tail gas is required per cubic meter of fly ash washing liquid.

[0106] (4) According to the water quality data of the fly ash washing liquid, add the fly ash washing liquid and the alkali solution into the reaction chamber simultaneously. Then, introduce CO2 through the three-phase mixer. Utilize the local negative pressure generated in the three-phase separator to suck the liquid-solid mixture into the nozzle and spray it upward under pressure. During the upward movement, it collides with the mushroom head and mixes violently, generating fine nano-scale small bubbles, and fully mixing and reacting the gas-liquid-solid three phases for 30 minutes. Keep the three phases in the reaction chamber in a suspension state without sedimentation and stratification to form a suspension.

[0107] (5) Adjust the weir plate mechanism near the first water production chamber to make the suspension in the reaction chamber flow into the first water production chamber through the flow channel. When the volume of the suspension in the first water production chamber reaches the set liquid level, close the flow channel on the side of the first water production chamber. The suspension in the first water production chamber is allowed to stand for 20 minutes. After solid-liquid separation, use the water production pump to transport the produced water to the water production tank for storage.

[0108] (6) When the volume of the suspension in the first water production chamber reaches the set liquid level, adjust the weir plate mechanism near the second water production chamber to make the suspension in the reaction chamber flow into the second water production chamber through the flow channel until the volume of the suspension inside reaches the set liquid level. The suspension in the second water production chamber is allowed to stand for 20 minutes. After solid-liquid separation, use the water production pump to transport the produced water to the water production tank for storage.

[0109] (5) The sludge at the bottoms of the above-mentioned first water production chamber and second water production chamber is discharged from the sludge outlet, and a cleaning spray device can be used to wash the residual sludge in the flow-through channel to avoid sludge blockage of the flow-through channel.

[0110] In this embodiment, the pH of the produced water is 9.5, the calcium ion concentration is 35.6 mg / L, the magnesium ion content is 0.3 mg / L, the removal rate of calcium ions can reach 99.5%, and according to the water quality test data, the carbon dioxide absorption efficiency is 89.7%.

[0111] Example 3

[0112] This embodiment adopts Figure 1 、 Figure 2 the integrated device for efficiently reducing the hardness of fly ash washing liquid shown in the figure to treat the fly ash washing liquid, and the specific process is as follows:

[0113] (1) Initial water quality conditions: the pH of the fly ash washing liquid is 13, the calcium ion content is 4.5 g / L, and the magnesium ion content is 0.1 g / L; use carbon dioxide with a volume fraction of ≥99.5%.

[0114] (2) Calculated dosage of alkali solution: Since the pH of the fly ash washing liquid already meets the conditions, no alkali solution needs to be added;

[0115] (3) CO2 dosage calculation: The target pH of the produced water is 10.5. According to formula (b), the calculation result is that 4.95 kg of CO2 needs to be introduced into each cubic meter of fly ash washing liquid. The volume fraction of carbon dioxide is greater than 99.5%, so 5 kg of industrial carbon dioxide is needed for each cubic meter of fly ash washing liquid.

[0116] (4) According to the water quality data of the fly ash washing liquid, the fly ash washing liquid and the alkali solution are simultaneously added to the reaction chamber, and then CO2 is introduced through a three-phase mixer. Using the local negative pressure generated in the three-phase separator, the liquid-solid mixture is sucked into the nozzle and then sprayed upward under pressure. During the rising process, it collides with the mushroom head and is violently mixed to generate fine nanoscale small bubbles, and the gas-liquid-solid three phases are fully mixed and reacted for 30 minutes. The nanoscale bubbles enable CO2 to react quickly with the high-pH fly ash washing liquid to form a suspension.

[0117] (5) Adjust the weir plate mechanism on the side close to the first water production chamber to make the suspension in the reaction chamber flow into the first water production chamber through the flow-through channel. When the volume of the suspension in the first water production chamber reaches the set liquid level, close the flow-through channel on the side of the first water production chamber. The suspension in the first water production chamber is allowed to stand for 30 minutes. After solid-liquid separation, a water production pump is used to transport the produced water to the water production tank for storage.

[0118] When the volume of the suspension in the first water production chamber reaches the set liquid level, adjust the weir plate mechanism on the side close to the second water production chamber to make the suspension in the reaction chamber flow into the second water production chamber through the flow channel until the volume of the internal suspension reaches the set liquid level. Let the suspension in the second water production chamber stand for 30 minutes. After solid-liquid separation, use a water production pump to transport the produced water to the water production tank for storage.

[0119] (5) The high-density sludge at the bottoms of the above-mentioned first water production chamber and second water production chamber is discharged from the sludge outlet. The flow channel can be rinsed once a day using a cleaning spray device to ensure that there is no residue in the flow channel.

[0120] The pH of the produced water in this embodiment is 10.3, the calcium ion concentration is 38 mg / L, the magnesium ion content is 0.21 mg / L, the removal rate of calcium ions can reach 99.1%, and according to the water quality test data, the carbon dioxide absorption efficiency is 90.2%.

[0121] In summary, through the integrated device for efficiently reducing the hardness of fly ash washing liquid, the present invention directly reduces the calcium ion content in the fly ash washing liquid to below 45 mg / L and the magnesium ion content to below 5 mg / L, effectively reducing the hardness of the produced water. It does not require continuous treatment by multiple operating units, has simple operation, low equipment investment and maintenance costs, and high treatment efficiency; the carbon dioxide absorption efficiency can reach more than 90%, which can quantitatively absorb waste flue gas containing CO2 and the tail gas of cement kilns to remove hardness, saving sodium carbonate reagents while reducing carbon emissions and treatment costs.

[0122] Those of ordinary skill in the art in this technical field should recognize that the above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. As long as it is within the scope of the spirit of the present invention, changes and modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. An integrated device for efficiently reducing the hardness of fly ash washing liquid, characterized in that, It includes a box body, a pH detection unit arranged inside the box body, a chemical dosing unit and an aeration unit connected to the box body; A top cover is arranged above the box body, and an aeration connection port connected to the aeration unit is arranged on the top cover; the box body includes a reaction chamber, a first water production chamber and a second water production chamber respectively arranged on both sides of the reaction chamber; Weir plate mechanisms and overflow channels are arranged on both sides of the reaction chamber. There are overflow ports left between the top of the two side walls of the reaction chamber and the top cover. The reaction chamber is communicated with the first water production chamber and the second water production chamber respectively through the overflow ports and overflow channels on both sides thereof. The weir plate mechanism realizes the disconnection and connection of the overflow channel through the lifting of the adjustable weir plate; an inlet for connecting with fly ash washing liquid and a chemical dosing port connected to the chemical dosing unit are arranged on the side surface of the reaction chamber, and a drain port is arranged at the bottom of the reaction chamber. A three-phase mixer connected to the aeration unit is arranged inside the reaction chamber; Water production outlets are arranged on the side surfaces of the first water production chamber and the second water production chamber, and sludge ports are opened at the bottoms; The pH detection unit is arranged in the water production outlets of the first water production chamber and the second water production chamber and in the overflow channel.

2. The integrated device for efficiently reducing the hardness of fly ash washing liquid according to claim 1, characterized in that, The upper parts of the reaction chamber, the first water production chamber and the second water production chamber are of rectangular cylinder structures, and the lower parts are of frustum cylinder structures.

3. The integrated device for efficiently reducing the hardness of fly ash washing liquid according to claim 1, characterized in that, The weir plate mechanism includes an adjustable weir plate and a lifting mechanism connected to the adjustable weir plate. The adjustable weir plate performs a lifting action along the side wall of the reaction chamber under the action of the lifting mechanism.

4. The integrated device for efficiently reducing the hardness of fly ash washing liquid according to claim 1, characterized in that: A cleaning spray device is arranged at the top position of the overflow channel, and the cleaning spray device is connected to a flushing water bypass.

5. The integrated device for efficiently reducing the hardness of fly ash washing liquid according to claim 1, characterized in that: The gas inlet of the three-phase mixer is connected to the aeration unit; Nozzles and a plurality of mushroom heads with a hydraulic shearing function are arranged inside the three-phase mixer, and the material of the mushroom heads is selected from modified PP, ABS or PTFE.

6. The integrated device for efficiently reducing the hardness of fly ash washing liquid according to claim 1, characterized in that: The three-phase mixer is arranged at the middle position of the bottom of the upper rectangular cylinder structure of the reaction chamber, and the installation heights of the inlet and the chemical dosing port are close to the installation height of the outlet of the three-phase mixer.

7. A method for efficiently reducing the hardness of fly ash washing liquid, characterized in that: Use the integrated device for efficiently reducing the hardness of fly ash washing liquid as described in any one of claims 1 to 6 to perform the following steps: S1. According to the water quality data of the fly ash washing liquid, add the fly ash washing liquid and alkali liquor into the reaction chamber at the same time, and then pass CO2 through the three-phase mixer for sufficient mixing reaction to obtain a suspension; S2. Adjust the weir plate mechanism on one side of the reaction chamber. The suspension in the reaction chamber overflows to the first water production chamber through the overflow channel on one side. When the volume of the suspension in the first water production chamber reaches the set liquid level, close the corresponding overflow channel, adjust the weir plate mechanism on the other side of the reaction chamber, and the suspension in the reaction chamber overflows into the second water production chamber until the volume of the suspension in the second water production chamber reaches the set liquid level; S3. After the volumes of the suspensions in the first water production chamber and the second water production chamber reach the set liquid levels, let them stand. After solid-liquid separation, the upper water production is transported to a water production tank, and the lower solid phase is discharged through the sludge port.

8. The method for efficiently reducing the hardness of fly ash washing liquid according to claim 7, characterized in that: In step S1: The pH of the fly ash washing liquid is 9 to 13, the calcium ion content is 5 to 20 g / L, and the magnesium ion content is 0.1 to 0.5 g / L; The CO2 is selected from CO2 in cement kiln tail gas, CO2 in waste flue gas or industrial carbon dioxide, and its volume fraction is ≥ 5%; The mixing reaction time is 10 to 30 minutes.

9. The method for efficiently reducing the hardness of fly ash washing liquid according to claim 8, characterized in that: In the step S1, the alkali solution is selected as sodium hydroxide solution; When the pH of the fly ash washing liquid > 11.5, no alkali solution is introduced into the reaction chamber; When the pH of the fly ash washing liquid ≤ 11.5, the addition amount of the alkali solution is as follows: where m NaOH is the mass of the lye, in g; V is the volume of the fly ash washing liquid, in liters; pH 目标 is the target pH of the fly ash washing liquid, and its range is 11.5 to 12; pH 初始 is the initial pH of the fly ash washing liquid; [Mg 2+ is the concentration of Mg 2+ , with the unit of g / L; [Ca 2+ is the concentration of Ca 2+ , with the unit of g / L.

10. The method for efficiently reducing the hardness of fly ash washing liquid according to claim 9, characterized in that: In the step S1, the introduction amount of the CO2 is as follows: wherein, is the mass of CO2, in g; [Ca 2+ is the concentration of Ca 2+ , with the unit of g / L; pH 反应前 is the pH of the fly ash washing liquid before reaction, and its range is 11.5 to 13; pH 终点 is the pH at the end of water production, and its range is 9.5 to 10.5; V is the volume of the fly ash washing liquid, in liters.

11. The method for efficiently reducing the hardness of fly ash washing liquid according to claim 7, characterized in that: In the step S3: The standing time is 10 to 30 minutes; In the step S3, the pH of the produced water is 9.5 to 10.5, the calcium ion content ≤ 45 mg / L, and the magnesium ion content ≤ 5 mg / L.

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