A resin regeneration wastewater neutralization system

Abstract

This application provides a resin regeneration wastewater neutralization system, relating to the field of ion-exchange membrane caustic soda production technology. It includes: a desorption unit, comprising a liquid phase outlet and a gas phase outlet, for desorption of acetylene from the waste alkali solution from the acetylene purification and neutralization tower; a regeneration wastewater pretreatment tank, the inlet of which is connected to the liquid phase outlet of the desorption unit and a resin regeneration wastewater pipeline, the resin regeneration wastewater pipeline being used to transport the regeneration wastewater generated during resin regeneration; and a mixing device, the inlet of which is connected to the outlet of the regeneration wastewater pretreatment tank and a neutralization alkali consumption conveying pipeline, the neutralization alkali consumption conveying pipeline being used to transport neutralization alkali. The waste alkali solution is used to adjust the pH of the regeneration wastewater to ≤4; the neutralization alkali is used to adjust the pH of the regeneration wastewater to 7-8. Utilizing waste alkali solution to neutralize the regeneration wastewater reduces neutralization costs. Before sending the waste alkali solution to the regeneration wastewater pretreatment tank, the desorption unit first removes acetylene from the waste alkali solution to ensure system safety.

Description

Technical Field

[0001] This utility model relates to the field of ion-exchange membrane caustic soda production technology, and in particular to a resin regeneration wastewater neutralization system. Background Technology

[0002] The primary brine refining process in the ion-exchange membrane caustic soda electrolysis mainly involves pretreating the crude brine to remove impurities, yielding primary refined brine (which, after secondary refining, becomes secondary refined brine), providing qualified raw materials for subsequent electrolysis processes. The primary brine refining process in the ion-exchange membrane caustic soda electrolysis process includes: dissolving raw salt in water and adding barium chloride to remove sulfate ions, forming crude brine; while the crude brine passes through a pre-processor and membrane filter, refining agents such as sodium hydroxide are added, and the brine is neutralized with hydrochloric acid through a dry salt saturation system to become primary refined brine. The primary refined brine then undergoes secondary refining through a chelating resin tower to further remove residual calcium and magnesium ions, meeting the anti-clogging requirements of the electrolytic cell's ion-exchange membrane.

[0003] The resin in the aforementioned resin tower is typically regenerated every 48 hours, producing regeneration wastewater with a hydrochloric acid concentration of approximately 5 g / L (acidic), and a single regeneration volume of approximately 171 m³. 3 The regenerated wastewater needs to be neutralized to a pH of 7-8 before it can enter subsequent wastewater treatment facilities or be reused. The neutralization of resin regeneration wastewater consumes a large amount of alkali; each regeneration of the resin tower consumes approximately 0.8-1 ton of 100% alkali, resulting in high neutralization costs.

[0004] In other equipment within the company, acetylene purification and neutralization towers are used. The waste alkaline solution produced in these towers has an alkali content of ≤7% and a sodium carbonate content of 4-7%. This waste alkaline solution is typically added directly to the water generation system for use as generated water. However, due to the high sodium carbonate content, sodium carbonate crystals easily form, causing blockage of the tower packing. Therefore, when the alkali content is high, it is discharged from the acetylene purification and neutralization tower as acetylene generated water, resulting in ineffective utilization of the alkali and a waste of resources.

[0005] The purpose of this application is to use the waste alkaline solution generated by the acetylene purification and neutralization tower to neutralize the regeneration acidic wastewater of the resin tower, so as to reduce the neutralization cost of the resin regeneration wastewater. Utility Model Content

[0006] In view of the above situation, this utility model provides a resin regeneration wastewater neutralization system, which aims to use the waste alkaline solution generated by the acetylene purification and neutralization tower to neutralize the regeneration acidic wastewater of the resin tower, so as to reduce the neutralization cost of resin regeneration wastewater.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] This utility model provides a resin regeneration wastewater neutralization system, comprising:

[0009] The desorption unit, including a liquid phase outlet and a gas phase outlet, is used to desorb acetylene from the waste alkaline solution from the acetylene purification and neutralization tower.

[0010] The inlet of the regenerated wastewater pretreatment tank is connected to the liquid phase outlet of the desorption unit and the resin regeneration wastewater pipeline. The resin regeneration wastewater pipeline is used to transport the regeneration wastewater generated during resin regeneration.

[0011] The mixing equipment has its inlet connected to the outlet of the primary conditioning tank for regenerated wastewater and the neutralization alkali conveying pipeline, which is used to convey neutralization alkali.

[0012] Among them, the waste alkali solution is used to adjust the pH of the regenerated wastewater to ≤4; the neutralization alkali is used to adjust the pH of the regenerated wastewater to 7~8.

[0013] In some embodiments of this utility model, the desorption mechanism includes a desorption tower, the upper part of which has a packing section and a waste gas outlet, and the lower part has a desorption tank;

[0014] The exhaust gas outlet is located above the packing section;

[0015] The packing section is filled with packing material for removing acetylene from the waste alkaline solution, and the packing section has a waste alkaline solution inlet;

[0016] The outlet of the desorption tank is connected to the inlet of the primary conditioning tank for reclaimed wastewater.

[0017] In some embodiments of this utility model, the desorption tank is provided with a first aeration pipe.

[0018] In some embodiments of this utility model, the first aeration pipe is connected to a nitrogen delivery pipe.

[0019] In some embodiments of this invention, the outlet of the desorption tank is connected to the inlet of the waste alkali solution.

[0020] In some embodiments of this utility model, the initial conditioning tank for regenerated wastewater is equipped with a second aeration pipe.

[0021] In some embodiments of this invention, the gas phase outlet of the desorption mechanism is connected to a negative pressure suction pipe.

[0022] In some embodiments of this invention, the mixing device includes a pipeline mixer.

[0023] In some embodiments of this utility model, a pH meter is installed at the outlet of the pipeline mixer, and an alkali replenishment valve is installed on the neutralization alkali delivery pipeline, which is associated with the pH meter.

[0024] In some embodiments of this invention, the outlet of the pipe mixer is connected to a neutral wastewater tank.

[0025] The embodiments of this utility model have at least the following advantages or beneficial effects:

[0026] 1. Neutralizing regeneration wastewater with waste alkali solution reduces neutralization costs. In this embodiment, the regeneration wastewater generated during resin regeneration is first neutralized to pH ≤ 4 in the initial conditioning tank using waste alkali solution (alkali content ≤ 7%, sodium carbonate content 4~7%) from the acetylene purification and neutralization tower. This ensures that no calcium carbonate precipitation occurs while effectively discharging the carbon dioxide generated by the reaction of sodium carbonate in the waste alkali solution with the acidic regeneration wastewater. Subsequently, the regeneration wastewater is sent to a mixing device to be neutralized to pH 7~8 by neutralizing alkali, resulting in neutral wastewater that can be used in subsequent processes.

[0027] 2. Before sending the waste alkaline solution to the primary conditioning tank for regenerated wastewater, acetylene is first removed from the waste alkaline solution through a separation mechanism to ensure the safety of the system.

[0028] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the resin regeneration wastewater neutralization system.

[0031] icon:

[0032] 1-Desorption tower, 11-Packing section, 111-Waste alkali inlet, 12-Waste gas outlet, 121-Negative pressure suction pipe, 13-Desorption tank, 131-Desorption tank outlet, 132-Waste alkali pump, 133-First aeration pipe

[0033] 2- Initial conditioning tank for reclaimed wastewater, 21- Second aeration pipe,

[0034] 3-Pipeline mixer, 31-pH meter, 32-Alkali replenishment valve,

[0035] 4- Waste alkali solution conveying pipeline,

[0036] 5- Resin regeneration wastewater pipeline,

[0037] 6- Neutralization and alkali-consuming transport pipeline,

[0038] 7-Nitrogen delivery pipeline, 71-Flow meter, 72-Flow regulating valve

[0039] 8- Compressed air delivery pipeline,

[0040] 9- Neutral wastewater tank. Detailed Implementation

[0041] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the present invention.

[0042] In the description of the embodiments of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0043] In this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention according to the specific circumstances.

[0044] The embodiments of this utility model will be described in detail below.

[0045] Example 1

[0046] See Figure 1 This embodiment provides a resin regeneration wastewater neutralization system, including a desorption mechanism, a regeneration wastewater pretreatment tank 2, and a mixing device.

[0047] The removal mechanism is used to remove acetylene from the waste alkaline solution from the acetylene purification and neutralization tower. The removal mechanism includes a liquid phase outlet and a gas phase outlet; the gas phase outlet is used to discharge acetylene, and the liquid phase outlet is used to discharge the waste alkaline solution. The removal mechanism will be illustrated in Example 2 below.

[0048] The inlet of the regenerated wastewater preconditioning tank 2 is connected to the liquid phase outlet of the desorption unit and the resin regeneration wastewater pipeline 5. The resin regeneration wastewater pipeline 5 is used to transport the regeneration wastewater generated during resin regeneration to the regeneration wastewater preconditioning tank 2. The waste alkali solution is used to adjust the pH of the regeneration wastewater to ≤4.

[0049] The inlet of the mixing equipment is connected to the outlet of the primary conditioning tank 2 for regenerated wastewater and the neutralization alkali conveying pipeline 6. The neutralization alkali conveying pipeline 6 is used to transport neutralization alkali, which is used to adjust the pH of the regenerated wastewater to 7-8. The desorption mechanism will be illustrated in Example 3 below.

[0050] This embodiment utilizes waste alkali solution to neutralize regeneration wastewater, reducing neutralization costs. First, in the initial conditioning tank 2, waste alkali solution (alkali content ≤7%, sodium carbonate content 4~7%) from the acetylene purification and neutralization tower is used to neutralize the regeneration wastewater generated during resin regeneration to pH ≤4. This ensures that no calcium carbonate precipitation occurs while effectively discharging the carbon dioxide generated by the reaction of sodium carbonate in the waste alkali solution with the acidic regeneration wastewater. Subsequently, the regeneration wastewater is sent to a mixing device to be neutralized to pH 7~8 by neutralizing alkali, resulting in neutral wastewater that can be used in subsequent processes.

[0051] In addition, considering that the acetylene dissolved in the waste alkali solution is prone to accumulation when transported to other equipment, and that acetylene is a flammable and explosive substance posing a safety risk, the acetylene is first removed from the waste alkali solution by a desorption mechanism before being sent to the primary conditioning tank 2 for regenerated wastewater to ensure the safety of the system.

[0052] Example 2

[0053] This embodiment is a specific implementation of the desorption / resorption mechanism.

[0054] See Figure 1 The desorption unit includes a desorption tower 1. The upper part of the desorption tower 1 has a packing section 11 and a waste gas outlet 12, and the lower part has a desorption tank 13. The waste gas outlet 12 is located above the packing section 11. The packing section 11 is filled with packing material for desorption of acetylene from the waste alkali solution. The packing section 11 has a waste alkali solution inlet 111. The waste alkali solution inlet 111 is connected to the waste alkali solution outlet of the acetylene purification and neutralization tower through a waste alkali solution conveying pipe 4. The waste alkali solution conveying pipe 4 is used to convey the waste alkali solution to the desorption tower 1.

[0055] The gas phase outlet of the desorption unit is the waste gas outlet 12; the liquid phase outlet of the desorption unit is the outlet 131 of the desorption tank, and the outlet 131 of the desorption tank is connected to the inlet of the regenerated wastewater primary conditioning tank 2 through the waste alkali pump 132.

[0056] After entering the desorption tower 1 through the waste alkali inlet 111, the waste alkali solution falls into the desorption tank 13 through the packing section 11, causing acetylene to be desorbed from the waste alkali solution. The acetylene is discharged from the waste gas outlet 12. After the acetylene is desorbed, the waste alkali solution enters the regeneration wastewater pretreatment tank 2.

[0057] The lower part of the desorption tank 13 is provided with a first aeration pipe 133, which is connected to a nitrogen delivery pipe 7. The nitrogen delivery pipe 7 is equipped with a flow meter 71 and a flow regulating valve 72 to control the nitrogen flow rate, so that the waste alkaline liquid in the desorption tank 13 is aerated to further desorb acetylene. At the same time, the introduction of nitrogen can also reduce the content of gaseous oxygen and acetylene in the desorption tank 13, which helps to ensure the safety of the system.

[0058] Furthermore, the outlet 131 of the desorption tank is connected to the waste alkali inlet 111 via a waste alkali pump 132, so that the waste alkali that has undergone one desorption is returned to the desorption tower 1 for another desorption of acetylene. In this way, after the waste alkali has circulated in the desorption tower 1 for a period of time and the acetylene content dissolved in the waste alkali has reached a safe value, the waste alkali can be sent to the regenerated wastewater pretreatment tank 2, which is safer.

[0059] Example 3

[0060] See Figure 1 This embodiment is a further improvement on embodiment 1 or 2.

[0061] A second aeration pipe 21 is installed at the bottom of the primary conditioning tank 2 for regenerated wastewater. The second aeration pipe 21 is connected to a compressed air delivery pipe 8. The flow rate in the compressed air delivery pipe 8 is adjustable, which can improve the mixing effect of waste alkali solution and regenerated wastewater in the primary conditioning tank 2 for regenerated wastewater.

[0062] The gas phase outlet (exhaust gas outlet 12) of the desorption unit is connected to a negative pressure suction pipe 121 so that the desorbed acetylene is discharged in a timely manner.

[0063] The mixing equipment includes a pipeline mixer 3. The inlet of the pipeline mixer 3 is connected to the outlet of the regenerated wastewater pretreatment tank 2 and the neutralization alkali-consuming conveying pipeline 6 to neutralize the regenerated wastewater to pH 7-8. A pH meter 31 is installed at the outlet of the pipeline mixer 3, and an alkali replenishment valve 32 is installed on the neutralization alkali-consuming conveying pipeline 6. The alkali replenishment valve 32 is associated with the pH meter 31 to appropriately increase or decrease the amount of alkali added, ensuring that the regenerated wastewater is neutralized to pH 7-8. A neutral wastewater tank 9 is connected to the outlet of the pipeline mixer 3 for storing the aforementioned neutral wastewater.

[0064] Finally, it should be noted that the above are merely preferred embodiments of this application and are not intended to limit this application. For those skilled in the art, this application can have various modifications and variations. Without conflict, the embodiments and features described in the embodiments of this application can be arbitrarily combined with each other. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A resin regeneration wastewater neutralization system characterized by comprising: include: The desorption unit, including a liquid phase outlet and a gas phase outlet, is used to desorb acetylene from the waste alkaline solution from the acetylene purification and neutralization tower. The inlet of the regenerated wastewater pretreatment tank is connected to the liquid phase outlet of the desorption mechanism and the resin regeneration wastewater pipeline, which is used to transport the regeneration wastewater generated during resin regeneration. A mixing device, the inlet of which is connected to the outlet of the primary conditioning tank for the regenerated wastewater and the neutralization alkali conveying pipeline, the neutralization alkali conveying pipeline being used to convey neutralization alkali; The waste alkaline solution is used to adjust the pH of the regenerated wastewater to ≤4; the neutralization alkali is used to adjust the pH of the regenerated wastewater to 7~8.

2. The resin regeneration waste water neutralization system according to claim 1, characterized by, The desorption mechanism includes a desorption tower, the upper part of which has a packing section and a waste gas outlet, and the lower part has a desorption tank; The exhaust gas outlet is located above the packing section; The packing section is filled with packing material for removing acetylene from the waste alkaline solution, and the packing section has a waste alkaline solution inlet; The outlet of the desorption tank is connected to the inlet of the primary conditioning tank for regenerated wastewater.

3. The resin regeneration wastewater neutralization system according to claim 2, characterized by, The desorption tank is equipped with a first aeration pipe.

4. The resin regeneration wastewater neutralization system according to claim 3, characterized by, The first aeration pipe is connected to a nitrogen delivery pipe.

5. The resin regeneration wastewater neutralization system according to claim 2, characterized in that, The outlet of the desorption tank is connected to the inlet of the waste alkali solution.

6. The resin regeneration wastewater neutralization system according to claim 1, characterized in that, The primary conditioning tank for the reclaimed wastewater is equipped with a second aeration pipe.

7. The resin regeneration wastewater neutralization system according to claim 1, characterized in that, The gas phase outlet of the desorption unit is connected to a negative pressure suction pipe.

8. The resin regeneration wastewater neutralization system according to any one of claims 1 to 7, characterized in that, The mixing equipment includes a pipeline mixer.

9. The resin regeneration wastewater neutralization system according to claim 8, characterized in that, A pH meter is installed at the outlet of the pipeline mixer, and an alkali replenishment valve is installed on the neutralization alkali delivery pipeline, which is associated with the pH meter.

10. The resin regeneration wastewater neutralization system according to claim 8, characterized in that, The outlet of the pipeline mixer is connected to a neutral wastewater tank.

Images