Pretreatment system for waste acid and waste alkali

Abstract

The utility model relates to the technical field of waste liquid treatment, and particularly discloses a waste acid and waste alkali pretreatment system, which comprises a collection container, a waste acid storage tank, a waste alkali storage tank and a waste alkali storage tank, the preparation container is used for adjusting the pH value of the wastewater and comprises a sulfuric acid preparation tank and a liquid caustic soda preparation tank; the neutralization reaction tank is used for pretreating waste acid and waste alkali; the filter pressing device is used for filtering the neutralized waste acid and waste alkali; the intermediate tank is used for storing the waste liquid treated by the filter pressing device; the ion exchange device is used for removing heavy metal ions in the waste liquid; the second-effect concentration evaporator is used for concentrating the waste liquid; the crystallization device is used for crystallizing the concentrated waste liquid, and the filter pressing device, the intermediate tank, the ion exchange device and the second-effect concentration evaporator are sequentially connected with the crystallization device. The utility model provides a waste acid and waste alkali pretreatment system for pretreating waste packing barrel cleaning wastewater.

Description

Technical Field

[0001] The utility model relates to the technical field of waste liquid treatment, in particular to a pretreatment system for waste acid and waste alkali. Background Art

[0002] The generation of waste acids and alkalis is inevitable in industrial production processes. If these waste acids and alkalis are discharged directly without proper treatment, they will not only cause serious environmental pollution, but may also have long-term adverse effects on water bodies, soil and ecosystems.

[0003] The wastewater from the cleaning of waste packaging barrels in existing projects directly enters the biochemical treatment system for treatment. Since the waste packaging barrels are cleaned with alkaline solution, directly entering the biochemical treatment system may cause an impact on the biochemical treatment system and cause wastewater treatment agents to be wasted. Therefore, a waste acid and waste alkali pretreatment system is required to pretreat the wastewater from the cleaning of waste packaging barrels in existing projects before discharging it into the biochemical treatment system. Utility Model Content

[0004] In order to solve the problem that the waste water from cleaning waste packaging barrels in the existing project directly enters the biochemical treatment system for treatment, which will cause impact on the biochemical treatment system, the utility model provides a pretreatment system for waste acid and waste alkali.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions:

[0006] The embodiment of the present invention provides a pretreatment system for waste acid and waste alkali, comprising:

[0007] A collecting container for collecting waste acid and waste alkali, the collecting container comprising a waste acid storage tank and a waste alkali storage tank;

[0008] Preparation container, used for adjusting the pH value of wastewater, said preparation container comprises a sulfuric acid preparation tank and a liquid caustic soda preparation tank;

[0009] A neutralization reaction tank is used to pre-treat waste acid and waste alkali, and the neutralization reaction tank includes a first input end and a first output end, wherein the first input end is respectively connected to the waste acid storage tank, the waste alkali storage tank, the sulfuric acid preparation tank and the liquid alkali preparation tank;

[0010] a filter press device connected to the first output end, for filtering the neutralized waste acid and waste alkali;

[0011] an intermediate tank for storing waste liquid treated by the filter press;

[0012] Ion exchange device, used to remove heavy metal ions from wastewater;

[0013] The second-effect concentrating evaporator is used to concentrate the waste liquid;

[0014] The crystallization device is used to perform crystallization treatment on the concentrated waste liquid. The filter press device, the intermediate tank, the ion exchange device, the second-effect concentrating evaporator and the crystallization device are connected in sequence.

[0015] According to some embodiments of the present invention, a heat exchanger is further provided between the ion exchange device and the second-effect concentrating evaporator, and the heat exchanger is used to preheat the wastewater treated by the ion exchange device.

[0016] According to some embodiments of the present invention, a waste gas utilization device is further included, and the waste gas utilization device includes a condenser. The condenser includes a cold water end, a hot water end, a steam inlet end and a drainage end. The cold water end and the hot water end are respectively connected to the heat exchanger, and the two-effect concentrating evaporator includes an exhaust end connected to the steam inlet end.

[0017] According to some embodiments of the present invention, a waste gas spraying device for treating waste gas in the neutralization reaction tank and the filter press device is also included.

[0018] According to some embodiments of the present invention, the exhaust gas spray device includes a spray tower, a spray pump and a water collection tank, the neutralization reaction tank includes a first exhaust gas output end, the filter press device includes a second exhaust gas output end, and the first exhaust gas output end and the second exhaust gas output end are respectively connected to the spray tower.

[0019] According to some embodiments of the present invention, a demisting device is further included for separating droplets carried by the clean gas after treatment.

[0020] According to some embodiments of the present invention, two spray towers are provided.

[0021] According to some embodiments of the present invention, a stirring device is provided in the neutralization reaction tank.

[0022] The utility model has at least the following beneficial effects:

[0023] The utility model can effectively recycle and treat waste acid and waste alkali generated in industrial production through the pretreatment system of waste acid and waste alkali, thereby reducing pollution to the environment. The system collects waste acid and waste alkali respectively through a collection container, and then adjusts the pH value of the waste water through a preparation container to ensure the efficient conduct of the neutralization reaction. The neutralization reaction tank pre-treats the waste acid and waste alkali, and filters the neutralized waste acid and waste alkali through a filter press device to ensure the purity of the waste liquid. The intermediate tank stores the waste liquid treated by the filter press device, providing convenience for subsequent treatment. The ion exchange device removes heavy metal ions in the waste liquid, thereby increasing the recovery value of the waste liquid. The two-effect concentrating evaporator concentrates the waste liquid, reduces the volume of the waste liquid, and reduces the processing cost. The crystallization device performs crystallization treatment on the concentrated waste liquid to achieve effective recovery and resource utilization of waste acid and waste alkali. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a structural schematic diagram of a waste acid and waste alkali pretreatment system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following description of the present invention, with reference to the accompanying drawings, is provided to facilitate a more comprehensive understanding of the various embodiments of the present invention as defined in the claims and their equivalents. The description includes various specific details to assist understanding, but these details should be construed as merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present invention.

[0026] In the description of the present invention, descriptions of directions, such as up, down, front, back, left, right, etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as a limitation on the present invention.

[0027] It will be understood that when one element (e.g., a first element) is “connected” to another element (e.g., a second element), the element may be directly connected to the other element or an intervening element (e.g., a third element) may be present between the element and the other element.

[0028] The embodiment of the present invention provides a pretreatment system for waste acid and waste alkali, such as Figure 1 Shown, including:

[0029] The collecting container 10 is used to collect waste acid and waste alkali. The collecting container 10 includes a waste acid storage tank 11 and a waste alkali storage tank 12;

[0030] Preparation container 13, used for adjusting the pH value of wastewater, preparation container 13 includes sulfuric acid preparation tank 14 and liquid caustic soda preparation tank 15;

[0031] The neutralization reaction tank 100 is used to pre-treat the waste acid and waste alkali. The neutralization reaction tank 100 includes a first input end 110 and a first output end 120. The first input end 110 is connected to the waste acid storage tank 11, the waste alkali storage tank 12, the sulfuric acid preparation tank 14 and the liquid alkali preparation tank 15 respectively.

[0032] The filter press device 200 is connected to the first output end 120 and is used to filter the neutralized waste acid and waste alkali;

[0033] The intermediate tank 300 is used to store the waste liquid processed by the filter press device 200;

[0034] Ion exchange device 400, used to remove heavy metal ions from wastewater;

[0035] The second-effect concentrating evaporator 500 is used to concentrate the waste liquid;

[0036] The crystallization device 600 is used to perform crystallization treatment on the concentrated waste liquid. The filter press device 200, the intermediate tank 300, the ion exchange device 400, the second-effect concentrating evaporator 500 and the crystallization device 600 are connected in sequence.

[0037] The waste acid storage tank 11 and the waste alkali storage tank 12 are used to collect waste acid and waste alkali generated during industrial production. To adjust the pH of the wastewater, a sulfuric acid preparation tank 14 and a liquid alkali preparation tank 15 are used to prepare corresponding solutions. The waste acid and alkali are then fed into a neutralization reaction tank 100 in a certain proportion to neutralize some of the waste acid, maintaining the pH of the wastewater at 3. Sulfuric acid is used to adjust the pH of the waste alkali. The neutralization reaction tank 100 has a first input end 110 and a first output end 120. The first input end 110 connects to the waste acid storage tank 11, the waste alkali storage tank 12, the sulfuric acid preparation tank 14, and the liquid alkali preparation tank 15 to achieve acid-base neutralization. The waste acid and waste alkali enter the neutralization reaction tank 100 through the first input end 110. In the neutralization reaction tank 100, the waste acid and waste alkali undergo a neutralization reaction to produce neutral substances. The filter press device 200 is connected to the first output end 120 of the neutralization reaction tank 100 and is used to filter the neutralized waste acid and waste alkali to remove solid impurities.

[0038] The intermediate tank 300 is used to store the waste liquid processed by the filter press device 200. The filtered waste liquid is stored in the intermediate tank 300 and waits for further processing.

[0039] Ion exchange device 400 is used to remove heavy metal ions from wastewater, further improving wastewater treatment efficiency. The core component of ion exchange device 400 is ion exchange resin, a polymer material with fixed ion exchange capabilities. Its surface carries numerous functional groups that selectively adsorb heavy metal ions from wastewater. Wastewater first passes through the ion exchange resin, where the heavy metal ions in the resin exchange with ions on the resin, becoming adsorbed on the resin. Clean wastewater then flows out of the resin bed. When the resin has absorbed enough heavy metal ions, its exchange capacity decreases, requiring regeneration. Before regeneration, the resin is eluted with a 5% hydrochloric acid solution to displace the adsorbed heavy metal ions and restore the resin's exchange capacity. During this step, the heavy metal ions exchange with the hydrogen ions in the hydrochloric acid, forming the corresponding metal chlorides that enter the solution. Wastewater containing heavy metal ions generated during the elution process needs to be returned to the reaction tank for further treatment. This wastewater may need to pass through ion exchange device 400 again, or other methods such as chemical precipitation may be used to remove the heavy metal ions. The resin is rinsed with a 5% sodium hydroxide solution, a step called regeneration. The hydroxide ions in the sodium hydroxide solution react with the hydrogen ions on the resin to produce water and soluble metal hydroxides, restoring the resin to its original state and making it usable again. The regenerated resin regains its exchange capacity and can be reused to adsorb heavy metal ions from wastewater.

[0040] A second-effect evaporator is used to further reduce the salt content in wastewater. Evaporation reduces the volume of the wastewater, but increases the concentration of pollutants. It consists of two evaporation stages, referred to as the first and second effects. In the first-effect evaporation stage, the wastewater is heated to 116°C and a pressure of 0.1 MPa (megapascals). Raw steam (unused fresh steam) is used to preheat the wastewater. Raw steam here refers to steam generated directly from the boiler and used to provide heat. The steam (feed steam) generated during the first-effect evaporation process is used as the heat source for the second-effect evaporation process. This means that the steam generated during the first-effect evaporation process is used to heat the wastewater in the second-effect evaporation process, thereby recovering energy. In the second-effect evaporation stage, the wastewater is heated to 108°C and a pressure of -0.02 MPa (negative pressure), which is lower than the temperature and pressure of the first-effect evaporation process. This design helps further evaporate the water in the wastewater while reducing energy consumption. After the second-effect evaporation, the solid waste (waste residue) in the wastewater is separated and treated as hazardous waste.

[0041] The concentrated waste liquid enters the crystallization device 600 for crystallization treatment. In the waste water after the second-effect evaporation, solid waste (waste residue) is separated out. These waste residues usually contain high concentrations of salt and other non-volatile solutes. At this stage, the purpose of the waste residue entering the crystallization system is to convert the soluble salts in the waste residue into solid crystalline form through further evaporation and crystallization processes. The main purpose of treating waste water by crystallization is to separate and recycle useful substances. Through evaporation concentration or cooling, the concentration of solutes with crystallization properties in the waste water exceeds its solubility product to reach an oversaturated state, thereby crystallizing the excess solute. In this way, the salt in the waste water can be evaporated and crystallized, and then the mother liquor can be refluxed to the second-effect concentration evaporator 500.

[0042] The working principle of this utility model is as follows:

[0043] Waste acid and waste alkali are collected in the waste acid storage tank 11 and the waste alkali storage tank 12, respectively. These tanks serve as preliminary storage facilities for the centralized processing of these hazardous chemicals. The pH of the waste acid and waste alkali can be adjusted using the sulfuric acid preparation tank 14 and the liquid alkali preparation tank 15. Sulfuric acid and liquid alkali act as neutralizing agents, adjusting the pH of the waste liquid to facilitate the subsequent neutralization reaction. The neutralization reaction tank 100 receives liquid from the waste acid storage tank 11, the waste alkali storage tank 12, the sulfuric acid preparation tank 14, and the liquid alkali preparation tank 15. Here, the waste acid and waste alkali are neutralized through a neutralization reaction, producing a neutral or nearly neutral solution. During this process, the acidic and alkaline substances react to produce water and salt, thereby reducing the corrosiveness and hazardousness of the waste liquid. The neutralized reaction product is filtered through a filter press 200 to remove insoluble solid impurities. This step ensures that solid particles will not interfere with subsequent processing and also improves the purity of the waste liquid. The filtered waste liquid is stored in an intermediate tank 300 in preparation for subsequent processing steps. An ion exchange device 400 is used to remove heavy metal ions from the waste liquid. Through ion exchange, heavy metal ions can be separated from the waste liquid, reducing their impact on the environment. A secondary concentrating evaporator 500 is used to concentrate the waste liquid and reduce its volume. The concentrated waste liquid enters a crystallization device 600 for crystallization. This step can convert certain components in the waste liquid into solid crystalline form, facilitating further recovery or safe disposal.

[0044] In some embodiments, a heat exchanger 700 is further provided between the ion exchange device 400 and the second-effect concentrating evaporator 500 . The heat exchanger 700 is used to preheat the wastewater treated by the ion exchange device 400 .

[0045] The heat exchanger 700 can use the hot liquid steam (i.e., the steam that has been used) from the second-effect evaporator to preheat the wastewater that has undergone ion exchange treatment. In this way, the wastewater is heated before entering the evaporator, reducing the additional heat that the evaporator needs to provide, thereby saving energy. During the second-effect evaporation process, the steam generated by the first-effect evaporation is used as the heat source for the second effect. The heat exchanger 700 can further recover the heat of this steam and transfer it to the wastewater, which can reduce the use of raw steam and improve the energy efficiency of the entire system. Through preheating by the heat exchanger 700, the evaporator's demand for raw steam can be reduced. Raw steam usually requires a higher energy cost to produce, so reducing its use can reduce overall operating costs. The heat exchanger 700 can accurately control the temperature of the wastewater to ensure that it reaches the optimal temperature before entering the evaporator, which is very important for improving evaporation efficiency and preventing equipment overheating.

[0046] Furthermore, the pretreatment system for waste acid and waste alkali also includes a waste gas utilization device 800, which includes a condenser 810. The condenser 810 includes a cold water end 820, a hot water end 830, a steam inlet end 840 and a drainage end 850. The cold water end 820 and the hot water end 830 are respectively connected to the heat exchanger 700, and the second-effect concentrating evaporator 500 includes an exhaust end 510 connected to the steam inlet end 840.

[0047] The condenser 810 in the waste gas utilization device 800 consists of four main components: a cold water end 820, a hot water end 830, a steam inlet end 840, and a drain end 850. These components work together to cool and condense the waste gas. The cold water end 820 and the hot water end 830 are each connected to the heat exchanger 700. The cold water end 820 receives the cooling medium (such as cold water), while the hot water end 830 discharges the heated medium. The steam inlet end 840 of the second-effect concentrating evaporator 500 is connected to the steam exhaust end 510 of the condenser 810. This connection allows the steam generated by the evaporator to enter the condenser 810 directly for condensation, thereby achieving efficient steam utilization and treatment. The waste gas enters the condenser 810 through the steam inlet end 840, gradually cools through the heat exchange process, and eventually condenses into a liquid inside the condenser 810. The condensed liquid is discharged through the drain end 850 for further processing or recycling.

[0048] In some embodiments, the pretreatment system for waste acid and waste alkali further includes a waste gas spraying device 900 for treating waste gas in the neutralization reaction tank 100 and the filter press device 200 .

[0049] The waste gas spraying device 900 typically includes one or more spraying layers composed of multiple nozzles for spraying an absorption liquid (such as an alkaline or acidic solution) into the waste gas stream. By combining the treatment of waste gases from two different sources, the waste gas spraying device 900 can more effectively manage waste gas emissions from the entire waste acid and waste alkali treatment system, reducing its impact on the environment.

[0050] Furthermore, the waste gas spraying device 900 includes a spray tower 930, a spray pump 940 and a water collecting tank 950, the neutralization reaction tank 100 includes a first waste gas output end 910, the filter press device 200 includes a second waste gas output end 920, and the first waste gas output end 910 and the second waste gas output end 920 are respectively connected to the spray tower 930.

[0051] The main structure of the spray tower 930, typically made of corrosion-resistant materials, houses the spray system and packing layer. The spray system comprises a network of distribution mains, branch pipes, and nozzles, atomizing the spray liquid for thorough contact with the exhaust gas. The demister 960, typically located above the last spray assembly at the top of the absorption tower, is used to separate droplets carried by the treated clean gas. The sump 950 collects the spray liquid, and its effective volume should be no less than twice the combined volume of the circulation pipeline and the packing liquid holding capacity. The filter press 200 may also generate some exhaust gas during the filter press process of the neutralized reactants. This exhaust gas is discharged through the second exhaust gas output port 920 and also transported to the exhaust gas spray device 900. The first and second exhaust gas output ports 910, 920, are connected to the exhaust gas spray device 900 via pipes or conduits to ensure smooth delivery of the exhaust gas to the spray device for treatment.

[0052] In some embodiments, the exhaust gas spraying device 900 further includes a demisting device 960 for separating liquid droplets carried by the treated clean gas.

[0053] The primary function of the demister 960 is to separate liquid droplets from the treated clean air. These droplets may contain incompletely neutralized acidic or alkaline substances, as well as other dissolved or suspended contaminants. By effectively removing these droplets, the demister 960 ensures that the exhaust gas reaches a higher level of cleanliness before discharge, reducing potential environmental impacts.

[0054] Furthermore, two spray towers 930 are provided.

[0055] In some embodiments, a stirring device 130 is provided in the neutralization reaction tank 100 .

[0056] The stirring device 130 ensures that the waste acid and waste alkali are fully mixed in the neutralization reaction tank 100, thereby improving the speed and efficiency of the neutralization reaction. By continuously stirring, the accumulation of precipitates generated during the reaction can be prevented, and the fluidity of the reaction tank and the continuity of the reaction can be maintained.

[0057] In some embodiments, the filter press device 200 includes a filter press 210 and a liquid pump 220 .

[0058] Filter press 210 applies pressure to force waste liquid through the filter medium, separating solid impurities from the liquid. Filtering can separate solid impurities from the waste liquid, reducing the amount of waste requiring further processing or disposal. Liquid pump 220 is used to transport waste liquid from collection container 10 to filter press 210, ensuring continuous flow of waste liquid into the filtration process. Liquid pump 220 provides the necessary pressure to overcome the resistance of the filter medium, maintaining the continuity and efficiency of the filtration process.

[0059] The terms and words used in the above description and claims are not limited to their literal meanings, but are merely used by the applicant to enable a clear and consistent understanding of the present invention. Therefore, it should be clear to those skilled in the art that the above description of various embodiments of the present invention is provided for illustration only and is not intended to limit the present invention as defined in the appended claims and their equivalents.

Claims

1. A pretreatment system for waste acid and waste alkali, characterized in that: include: A collecting container (10) is used to collect waste acid and waste alkali, wherein the collecting container (10) comprises a waste acid storage tank (11) and a waste alkali storage tank (12); A preparation container (13) is used to adjust the pH value of the wastewater, wherein the preparation container (13) includes a sulfuric acid preparation tank (14) and a liquid caustic soda preparation tank (15); A neutralization reaction tank (100) is used for pre-treating waste acid and waste alkali. The neutralization reaction tank (100) comprises a first input end (110) and a first output end (120). The first input end (110) is connected to the waste acid storage tank (11), the waste alkali storage tank (12), the sulfuric acid preparation tank (14), and the liquid alkali preparation tank (15), respectively. A filter press device (200), connected to the first output end (120), for filtering the neutralized waste acid and waste alkali; an intermediate tank (300) for storing waste liquid processed by the filter press device (200); an ion exchange device (400) for removing heavy metal ions from the waste liquid; A second-effect concentrating evaporator (500) is used to concentrate the waste liquid; The crystallization device (600) is used for performing crystallization treatment on the concentrated waste liquid. The filter press device (200), the intermediate tank (300), the ion exchange device (400), the second-effect concentrating evaporator (500) and the crystallization device (600) are connected in sequence.

2. The pretreatment system for waste acid and waste alkali according to claim 1, characterized in that: A heat exchanger (700) is further provided between the ion exchange device (400) and the second-effect concentrating evaporator (500), and the heat exchanger (700) is used to preheat the wastewater treated by the ion exchange device (400).

3. A pretreatment system for waste acid and waste alkali according to claim 2, characterized in that: The invention also includes a waste gas utilization device (800), wherein the waste gas utilization device (800) includes a condenser (810), and the condenser (810) includes a cold water end (820), a hot water end (830), a steam inlet end (840) and a drain end (850). The cold water end (820) and the hot water end (830) are respectively connected to the heat exchanger (700). The second-effect concentrating evaporator (500) includes a steam exhaust end (510) connected to the steam inlet end (840).

4. A pretreatment system for waste acid and waste alkali according to any one of claims 1 to 3, characterized in that: It also includes a waste gas spraying device (900) for treating waste gas in the neutralization reaction tank (100) and the filter press device (200).

5. The pretreatment system for waste acid and waste alkali according to claim 4, characterized in that: The waste gas spraying device (900) includes a spray tower (930), a spray pump (940) and a water collecting tank (950); the neutralization reaction tank (100) includes a first waste gas output end (910); the filter press device (200) includes a second waste gas output end (920); the first waste gas output end (910) and the second waste gas output end (920) are respectively connected to the spray tower (930).

6. The pretreatment system for waste acid and waste alkali according to claim 5, characterized in that: The waste gas spraying device (900) further comprises a demisting device (960) for separating liquid droplets carried by the clean gas after treatment.

7. The pretreatment system for waste acid and waste alkali according to claim 5, characterized in that: There are two spray towers (930).

8. A pretreatment system for waste acid and waste alkali according to any one of claims 1 to 3, characterized in that: A stirring device (130) is provided in the neutralization reaction tank (100).

9. A pretreatment system for waste acid and waste alkali according to any one of claims 1 to 3, characterized in that: The filter press device (200) comprises a filter press (210) and a liquid pump (220).

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