Method for recycling oxidized residual liquid in hydrogen peroxide production

Abstract

The application provides a recycling method for oxidation residual liquid in hydrogen peroxide production, and belongs to the technical field of hydrogen peroxide production, which comprises the following steps: 1) collecting the oxidation residual liquid of the upper tower of an oxidation tower into an upper residual liquid storage tank, and regularly returning the oxidation residual liquid into the lower tower of the oxidation tower to participate in the oxidation reaction of hydrogenated liquid; 2) collecting the oxidation residual liquid of the lower tower of the oxidation tower into a lower residual liquid storage tank, regularly sampling and detecting, and classifying and recycling according to the detection results; if the sample indexes meet the recycling standards, the oxidation residual liquid is discharged into an oxidation liquid tank; if the sample indexes do not meet the recycling standards, the oxidation residual liquid is discharged into an acidic sewage tank. In the application, the oxidation residual liquid of the upper tower and the lower tower of the oxidation tower is classified and recycled, the pollution discharge amount of the oxidation residual liquid is reduced, the efficiency and safety performance of the oxidation residual liquid recycling are improved, the recycling cost is reduced, the sewage treatment difficulty and cost are reduced, the yield and output of the hydrogen peroxide product are improved, and the production cost of the hydrogen peroxide is saved.

Description

Technical Field

[0001] This invention relates to the field of hydrogen peroxide production technology, and in particular to a method for recycling and utilizing oxidation residues in hydrogen peroxide production. Background Technology

[0002] Currently, most hydrogen peroxide manufacturers use the anthraquinone process to produce hydrogen peroxide. The anthraquinone process uses 2-ethylanthraquinone as a working carrier, which is mixed with heavy aromatics, phosphate esters, and acetate esters in a specific ratio to form a working solution. During hydrogen peroxide production, the working solution and hydrogen gas enter a hydrogenation tower containing a palladium catalyst for a hydrogenation reaction, generating a corresponding 2-ethylanthraquinone solution (referred to as the hydrogenated solution). The hydrogenated solution is then pumped into an oxidation tower where it is automatically oxidized by air. The hydrogen anthraquinone in the working solution is converted back to the original 2-ethylanthraquinone, and hydrogen peroxide is generated simultaneously (the working solution at this point is referred to as the oxidation solution). The oxidation solution is pumped from the oxidation solution tank into an extraction tower. Utilizing the difference in solubility and density of hydrogen peroxide in pure water and the working solution, pure water is used to extract the hydrogen peroxide-containing working solution, yielding an aqueous solution of hydrogen peroxide with a certain concentration (commonly known as hydrogen peroxide). After the hydrogen peroxide is further processed by heavy aromatics to absorb organic impurities, a qualified industrial-grade hydrogen peroxide product is obtained.

[0003] Because the oxidation reaction must be carried out under acidic conditions to prevent side reactions, the acidity is adjusted by injecting phosphoric acid into the hydrogenation liquid before it enters the oxidation tower. The phosphoric acid solution enters the oxidation tower along with the hydrogenation liquid via a hydrogenation liquid pump to undergo a chemical reaction. During this oxidation process in the oxidation tower, moisture carried by the air, moisture in the phosphoric acid, moisture in the hydrogenation liquid itself, and trace amounts of water produced by the decomposition of hydrogen peroxide extract the generated hydrogen peroxide into a highly concentrated hydrogen peroxide aqueous solution. Since this hydrogen peroxide aqueous solution has a higher density than the working liquid, it cannot enter the extraction tower with the large amount of oxidation liquid, and this solution remains at the bottom of both the upper and lower sections of the oxidation tower. We call this aqueous solution containing hydrogen peroxide and other impurities accumulated at the bottom of the oxidation tower the oxidation residue. The more water, the larger the amount of residue. In short, the oxidation residue is hydrogen peroxide with a high concentration of organic impurities, free acid, and low stability, extracted by water in the oxidation tower.

[0004] The hydrogen peroxide content in this portion of the aqueous solution ranges from 23% to 50%, and sometimes even higher. However, due to its generally low stability (40-70%), it is prone to decomposition and safety accidents, making it unsuitable for sale as a product. To avoid excessive residual oxidation liquid affecting the safe operation of the oxidation tower, the residual oxidation liquid from both the upper and lower towers must be discharged from the system regularly and at designated points along with the wastewater discharge from the upper and lower towers. As product capacity increases, the discharge volume and hydrogen peroxide concentration of the oxidation tower residual oxidation liquid also increase. However, residual oxidation liquid is unavoidable in the hydrogen peroxide production process; the more residual liquid, the greater the waste and the higher the production cost. Traditional treatment methods involve direct discharge to wastewater treatment plants, which increases the difficulty of wastewater treatment, pollutes the environment, and wastes products. Alternatively, the residual oxidation liquid can be layered, filtered, purified, and stabilized with added stabilizers for recycling. For example, the recycled residual oxidation liquid can be sold at a low price to users with lower hydrogen peroxide standards or used for wastewater treatment, but this increases treatment costs and complicates the process. Since the oxidation tower produces a large amount of oxidation residue every day, in order to better and more rationally recycle and utilize the oxidation residue, turn waste into treasure, and reduce costs and energy consumption, it is necessary to study a new recycling method to recover the oxidation residue in hydrogen peroxide production. Summary of the Invention

[0005] This invention provides a method for recycling oxidation residue in hydrogen peroxide production, which has high recycling efficiency, significantly reduces wastewater discharge, and increases the yield of hydrogen peroxide and the utilization rate of working fluid. It solves the problems of difficult wastewater treatment, resource waste, and environmental pollution caused by the direct discharge of oxidation residue in existing hydrogen peroxide production, as well as the problems of high treatment cost and cumbersome process in traditional oxidation residue recycling.

[0006] To achieve the above objectives, the present invention provides a method for recycling oxidation residue in hydrogen peroxide production, comprising: 1) Collect the oxidation residue from the upper column of the oxidation tower into the upper column residue storage tank, and periodically return it to the lower column of the oxidation tower to participate in the oxidation reaction of the hydrogenated liquid; 2) Collect the oxidation residue from the bottom of the oxidation tower into the bottom residue storage tank, take samples for testing regularly, and classify and recycle it according to the test results.

[0007] In this invention, the oxidation residue from the upper and lower sections of the oxidation tower is graded and classified for recycling according to its characteristics. This reduces the amount of wastewater discharged from the oxidation residue, which is beneficial to improving the efficiency and safety of the oxidation residue recycling, reducing its recycling cost, and avoiding direct discharge of the oxidation residue into wastewater treatment, thus reducing the difficulty and cost of wastewater treatment. Compared with the centralized recycling, fixed-point storage and centralized treatment methods in the same industry, this method has a lower risk factor, less labor intensity, and is easier to operate. It also timely recovers hydrogen peroxide and working fluid from the oxidation residue, which is beneficial to improving the yield of hydrogen peroxide products. Overall, it significantly improves the production of hydrogen peroxide and the utilization rate of the working fluid, and also saves on the production cost of hydrogen peroxide.

[0008] According to the present invention, in step 1), the frequency of returning the oxidation residue to the lower part of the oxidation tower is 2-3 times per day.

[0009] According to the present invention, in step 2), the sampling and testing frequency is 2-3 days / time. The amount of oxidation residue is relatively small compared to the production volume of hydrogen peroxide, so it can be recycled and treated regularly according to the frequency, avoiding the continuous accumulation of high concentrations of hydrogen peroxide and organic impurities in the oxidation residue. This not only solves the problem of hazardous waste treatment but also achieves safe production.

[0010] According to the present invention, in step 2), the specific steps of classification and recycling are as follows: if the sample indicators meet the recycling standards, the oxidation residue is discharged into the oxidation tank; if the sample indicators do not meet the recycling standards, the oxidation residue is discharged into the acidic wastewater tank. The composition content of the oxidation residue generated during production may fluctuate. In order to ensure the safe and stable operation of hydrogen peroxide production, there are certain standard requirements for the recycled oxidation residue. This ensures both the efficiency and effectiveness of oxidation residue recycling and the quality and stable output of hydrogen peroxide products, achieving a dynamic balance between oxidation residue recycling and hydrogen peroxide production. Oxidation residue that does not meet the recycling standards due to fluctuations in raw materials, etc., is directly discharged into the acidic wastewater tank for purification treatment according to traditional methods.

[0011] According to the present invention, the sample indicators that meet the recycling standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥65%. With the continuous improvement of palladium catalysts, acid washing and other technologies in the industry, the concentration and stability of oxidation residues are also constantly improving. The hydrogen peroxide concentration of the oxidation residue in the lower tower is generally 45-50%, and the stability is not less than 70%. Directly recycling this part of the oxidation residue, since the amount of oxidation residue is smaller than that of the oxidation liquid, will not cause safety problems such as decomposition and temperature rise due to a slight decrease in stability of the oxidation liquid. On the contrary, it can increase the yield of hydrogen peroxide products and save its production costs.

[0012] According to the present invention, the volume ratio of the residual oxidation liquid to the oxidizing liquid in the oxidation tank is 1:(50-500). The residual oxidation liquid is typically fed into the oxidation tank from the top to facilitate uniform mixing with the oxidizing liquid present therein. This residual oxidation liquid dissolves into the oxidizing liquid and, together with the oxidizing liquid, proceeds in the subsequent existing hydrogen peroxide production process. After extraction and purification, a qualified hydrogen peroxide product is produced, thus completing the recycling and reuse of the residual oxidation liquid. This process relies on existing hydrogen peroxide production processes and equipment, without the need for additional purification equipment, significantly saving recycling costs and increasing production revenue.

[0013] According to the present invention, the recycling method further includes: 3) before the oxidation residue in the upper column residual liquid storage tank is returned to the lower column of the oxidation tower, sampling and testing are performed. If the sample indicators meet the recycling standards, the oxidation residue is sent to the lower column residual liquid storage tank, and then sampling, testing and classification recycling are performed according to 2). Different recycling paths are provided for the oxidation residue in the upper column according to the concentration of the oxidation residue. Oxidation residue containing high concentration of hydrogen peroxide follows the high recovery rate path, prioritizing the recovery of hydrogen peroxide and working fluid. Oxidation residue containing low concentration of hydrogen peroxide follows the continued oxidation path. The two paths can significantly improve the recycling efficiency under different operating conditions, avoid the problem of poor adaptability of a single path, and make the whole recycling process more comprehensive and stable, ensuring that the oxidation residue can be controlled and disposed of at all times.

[0014] According to the present invention, in step 3), the sample indicators that meet the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥60%. The hydrogen peroxide concentration in the oxidation residue at the top of the oxidation tower is generally 23-35%. The portion of this oxidation residue with a lower hydrogen peroxide concentration can be selectively sent back to the bottom of the oxidation tower for further oxidation, allowing the unreacted anthraquinone in the low-concentration oxidation residue to continue its oxidation reaction in the bottom tower, reducing the ineffective loss of working fluid and hydrogen peroxide, and improving the overall product yield. Alternatively, the portion with a higher hydrogen peroxide concentration can be mixed with the oxidation residue at the bottom tower with an even higher hydrogen peroxide concentration. By blending the two oxidation residues and then testing and classifying them for recovery, a qualified hydrogen peroxide product can also be obtained.

[0015] According to the present invention, in step 3), the volume ratio of the oxidation residue from the upper column residual liquid storage tank that meets the recycling standards to the oxidation residue in the lower column residual liquid storage tank is 1:(1-20). After the oxidation residue from the upper column and the oxidation residue from the lower column are mixed in proportion, the stability of the mixed oxidation residue can be guaranteed to be ≥65%, which effectively ensures the concentration and stability of the oxidation residue and realizes the safe recycling and reuse of the oxidation residue.

[0016] According to the present invention, the recycling method further includes: 4) the oxidation residue is mixed evenly with the oxidation liquid in the oxidation tank, and then pumped into the extraction tower for extraction. The extract is then sent to the purification tower for purification, and finally, qualified industrial-grade hydrogen peroxide product is obtained. The oxidation tank, extraction tower, and purification tower are all conventional equipment in existing hydrogen peroxide production systems. After the oxidation residue and oxidation liquid are mixed, they are uniformly fed into the extraction tower, where they are countercurrently extracted with pure water to obtain crude hydrogen peroxide solution and raffinate. The crude hydrogen peroxide solution is then purified in the purification tower for heavy aromatics to remove impurities such as non-volatile matter, free acid, and organic degradation products, and to obtain hydrogen peroxide product that meets the GB / T1616-2014 standard. The operation process and process parameters of the oxidation tank, extraction tower, and purification tower are consistent with those in conventional hydrogen peroxide production and are not affected by the oxidation residue recovery process. Through this recycling process, the oxidation residue is recovered, the yield and output of hydrogen peroxide are improved, and the safety of the oxidation residue recycling process is also improved.

[0017] The method for recycling oxidation residue in hydrogen peroxide production provided by this invention has at least the following advantages and beneficial effects: 1) The oxidation residue from the upper and lower sections of the oxidation tower is classified and recycled according to its characteristics. The recycling efficiency of the oxidation residue is high. In the process of merging the oxidation residue and the oxidation liquid, there are requirements for the concentration and stability of the recycled oxidation residue. This ensures both the efficiency and effect of the oxidation residue recycling and the quality and stable output of hydrogen peroxide products. A dynamic balance is achieved between the recycling of oxidation residue and hydrogen peroxide production, thereby realizing the safe recycling and reuse of oxidation residue.

[0018] 2) This process provides different recovery paths based on the concentration of the oxidation residue, which greatly improves the recovery efficiency under different working conditions and avoids the problem of poor adaptability of a single path. The entire recovery process relies on the existing hydrogen peroxide production process and equipment, without the need to add additional purification equipment, which significantly saves recovery costs. It also recovers hydrogen peroxide and working fluid in the oxidation residue in a timely manner, which is conducive to improving the yield of hydrogen peroxide products. Overall, it significantly improves the output of hydrogen peroxide and the utilization rate of working fluid, saves the production cost of hydrogen peroxide, and increases production revenue.

[0019] 3) The recycling of oxidation residue can avoid direct discharge of oxidation residue into sewage treatment, reducing the amount of oxidation residue discharged, especially reducing the amount of acidic sewage discharged from the production system and the COD content of the discharged sewage, reducing the operating load and operating cost of sewage treatment. Compared with the centralized recycling, fixed-point storage and centralized treatment method in the same industry, it has a lower risk factor, less labor intensity and is easier to operate. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of the present invention.

[0021] The following examples use conventional instruments and equipment in the art. Unless otherwise specified, the experimental materials and reagents used in the following examples are commercially available and conform to conventional specifications in the art. Any techniques or conditions not specifically described in the following examples can be performed according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0022] It should be noted that, in this invention and the following embodiments, unless otherwise specified, concentration, ratio, etc. are all weight concentration, weight ratio, etc., "%" all represent weight percentage, and "parts" all represent weight parts. These are common writing habits used by those skilled in the art, and therefore will not be repeated in this invention.

[0023] As a preferred embodiment, the method for recycling oxidation residue in hydrogen peroxide production provided by the present invention includes the following specific steps: 1) Collect the oxidation residue from the upper column of the oxidation tower into the upper column residue storage tank, and return it to the lower column of the oxidation tower every 2-3 days to participate in the oxidation reaction of the hydrogenated liquid.

[0024] 2) Collect the oxidation residue from the bottom of the oxidation tower into a bottom residue storage tank. Take samples every 2-3 days for testing and classify them for recovery based on the test results. If the sample indicators meet the recovery standards, discharge the oxidation residue into the oxidation liquid tank. The volume ratio of oxidation residue to oxidation liquid in the oxidation liquid tank should be 1:(50-500). If the sample indicators do not meet the recovery standards, discharge the oxidation residue into the acidic wastewater tank. The sample indicators that meet the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥65%.

[0025] 3) Before the residual oxidation liquid in the upper column's residual liquid storage tank is returned to the lower column of the oxidation tower, it is sampled and tested. If the sample indicators meet the recovery standards, the residual oxidation liquid is sent to the lower column's residual liquid storage tank, and then sampled, tested, and classified for recovery as in step 2). The sample indicators that meet the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥60%. The volume ratio of the residual oxidation liquid from the upper column's residual liquid storage tank that meets the recovery standards to the residual oxidation liquid in the lower column's residual liquid storage tank is 1:(1-20).

[0026] 4) The residual oxidant from the lower tower residual liquid storage tank is mixed evenly with the oxidant in the oxidant tank, and then pumped into the extraction tower for extraction. The extract is then sent to the purification tower for purification, and finally qualified industrial-grade hydrogen peroxide products are obtained.

[0027] It should be noted that when discharging oxidation residue into the upper / lower tower residual liquid storage tank from the oxidation tower, the clear portion should be discharged into the upper / lower tower residual liquid storage tank only by using the interface of the stratified layers in the drain sight glass and the drain regulating valve. This prevents the heavy components with more impurities from being discharged into the upper / lower tower residual liquid storage tank. The heavy components should be discharged directly into the sewage treatment system through the existing drain pipeline.

[0028] The present invention will be further described in detail below with reference to embodiments. However, it should be understood that the embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0029] Example 1:

[0030] A method for recycling oxidation residue in hydrogen peroxide production includes the following steps: 1) Collect the oxidation residue from the upper column of the oxidation tower into the upper column residue storage tank, and return it to the lower column of the oxidation tower every 2 days to participate in the oxidation reaction of the hydrogenated liquid.

[0031] 2) Collect the oxidation residue from the bottom of the oxidation tower into a bottom residue storage tank. Take samples every two days for testing and classify them for recovery based on the test results. If the sample indicators meet the recovery standards, discharge the oxidation residue into the oxidation liquid tank at a volume ratio of 1:50. If the sample indicators do not meet the recovery standards, discharge the oxidation residue into the acidic wastewater tank. The sample indicators that meet the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥65%.

[0032] 3) The residual oxidant from the lower tower residual liquid storage tank is mixed evenly with the oxidant in the oxidant tank, and then pumped into the extraction tower for extraction. The extract is then sent to the purification tower for purification, and finally qualified industrial-grade hydrogen peroxide products are obtained.

[0033] Example 2:

[0034] A method for recycling oxidation residue in hydrogen peroxide production includes the following steps: 1) Collect the oxidation residue from the upper column of the oxidation tower into the upper column residue storage tank, and return it to the lower column of the oxidation tower every 3 days to participate in the oxidation reaction of the hydrogenated liquid.

[0035] 2) Collect the oxidation residue from the bottom of the oxidation tower into a residue storage tank. Take samples every 3 days for testing and classify the residue for recovery based on the test results. If the sample indicators meet the recovery standards, discharge the oxidation residue into the oxidation liquid tank at a volume ratio of 1:500. If the sample indicators do not meet the recovery standards, discharge the oxidation residue into the acidic wastewater tank. The sample indicators that meet the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥65%.

[0036] 3) The residual oxidant from the lower tower residual liquid storage tank is mixed evenly with the oxidant in the oxidant tank, and then pumped into the extraction tower for extraction. The extract is then sent to the purification tower for purification, and finally qualified industrial-grade hydrogen peroxide products are obtained.

[0037] Example 3:

[0038] A method for recycling oxidation residue in hydrogen peroxide production includes the following steps: 1) Collect the oxidation residue from the upper column of the oxidation tower into the upper column residue storage tank. Sampling and testing are performed every two days. If the sample indicators meet the recovery standards, the oxidation residue is sent to the lower column residue storage tank; if the sample indicators do not meet the recovery standards, it is returned to the lower column of the oxidation tower to participate in the oxidation reaction of the hydrogenated liquid. The sample indicators meeting the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥60%. The volume ratio of the oxidation residue from the upper column residue storage tank that meets the recovery standards to the oxidation residue in the lower column residue storage tank is 1:10.

[0039] 2) Collect the oxidation residue from the bottom of the oxidation tower into a residue storage tank. Take samples every 3 days for testing and classify the residue for recovery based on the test results. If the sample indicators meet the recovery standards, discharge the oxidation residue into the oxidation liquid tank at a volume ratio of 1:220. If the sample indicators do not meet the recovery standards, discharge the oxidation residue into the acidic wastewater tank. The sample indicators that meet the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥65%.

[0040] 3) The residual oxidant from the lower tower residual liquid storage tank is mixed evenly with the oxidant in the oxidant tank, and then pumped into the extraction tower for extraction. The extract is then sent to the purification tower for purification, and finally qualified industrial-grade hydrogen peroxide products are obtained.

[0041] Example 4:

[0042] A method for recycling oxidation residue in hydrogen peroxide production includes the following steps: 1) Collect the oxidation residue from the upper column of the oxidation tower into the upper column residue storage tank. Sampling and testing are performed every 3 days. If the sample indicators meet the recovery standards, the oxidation residue is sent to the lower column residue storage tank; if the sample indicators do not meet the recovery standards, it is returned to the lower column of the oxidation tower to participate in the oxidation reaction of the hydrogenated liquid. The sample indicators meeting the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥60%. The volume ratio of the oxidation residue from the upper column residue storage tank that meets the recovery standards to the oxidation residue in the lower column residue storage tank is 1:15.

[0043] 2) Collect the oxidation residue from the bottom of the oxidation tower into a bottom residue storage tank. Take samples every 3 days for testing and classify them for recovery based on the test results. If the sample indicators meet the recovery standards, discharge the oxidation residue into the oxidation liquid tank at a volume ratio of 1:350. If the sample indicators do not meet the recovery standards, discharge the oxidation residue into the acidic wastewater tank. The sample indicators that meet the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥65%.

[0044] 3) The residual oxidant from the lower tower residual liquid storage tank is mixed evenly with the oxidant in the oxidant tank, and then pumped into the extraction tower for extraction. The extract is then sent to the purification tower for purification, and finally qualified industrial-grade hydrogen peroxide products are obtained.

[0045] Comparative Example 1: A method for recycling oxidation residue in hydrogen peroxide production includes the following steps: 1) Collect the oxidation residue from the upper column of the oxidation tower into the upper column residue storage tank. Sampling and testing are performed every 3 days. If the sample indicators meet the recovery standards, the oxidation residue is sent to the lower column residue storage tank; if the sample indicators do not meet the recovery standards, it is returned to the lower column of the oxidation tower to participate in the oxidation reaction of the hydrogenated liquid. The sample indicators meeting the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥60%. The volume ratio of the oxidation residue from the upper column residue storage tank that meets the recovery standards to the oxidation residue in the lower column residue storage tank is 1:15.

[0046] 2) Collect the oxidation residue from the bottom of the oxidation tower into the bottom residue storage tank, take samples for testing every 3 days, and discharge all the oxidation residue into the oxidation liquid tank without sorting and recycling. The volume ratio of oxidation residue to oxidation liquid in the oxidation liquid tank is 1:350.

[0047] 3) The residual oxidant from the lower tower residual liquid storage tank is mixed evenly with the oxidant in the oxidant tank, and then pumped into the extraction tower for extraction. The extract is then sent to the purification tower for purification, and finally hydrogen peroxide product is obtained.

[0048] Comparative Example 2: A method for recycling oxidation residue in hydrogen peroxide production includes the following steps: 1) Collect the oxidation residue from the upper column of the oxidation tower into the upper column residue storage tank. Sampling and testing are performed every 3 days. If the sample indicators meet the recovery standards, the oxidation residue is sent to the lower column residue storage tank; if the sample indicators do not meet the recovery standards, it is returned to the lower column of the oxidation tower to participate in the oxidation reaction of the hydrogenated liquid. The sample indicators meeting the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥60%. The volume ratio of the oxidation residue from the upper column residue storage tank that meets the recovery standards to the oxidation residue in the lower column residue storage tank is 1:15.

[0049] 2) Collect the oxidation residue from the bottom of the oxidation tower into the bottom residue storage tank. Take samples for testing every 3 days. Then, cool the oxidation residue to below 30°C using a cooler. Then, purify it through a resin tower and then filter it to remove phosphates, undissolved degradation products and organic impurities. Finally, send the purified oxidation residue into a mixing storage tank.

[0050] The oxidation residue discharged from the oxidation tower was recycled according to the methods of Examples 1-4 and Comparative Examples 1-2. Samples were taken from each test group at the same time and in the same quantity. The oxidation residue from the upper tower, the oxidation residue from the lower tower, and the final product were sampled and tested. The results are shown in Table 1 below. Each test group had 3 replicates, and the average value was taken.

[0051] Table 1

[0052] As shown in the table above, when the oxidation residue is recycled and reused according to the method in the examples, the impurities and stability of the oxidation residue in the upper and lower towers do not affect the quality of the final hydrogen peroxide product after extraction and purification operations in the extraction and purification towers. On the contrary, the recycling of the oxidation residue can increase the yield of hydrogen peroxide product. In Comparative Example 1, since the oxidation residue is not sorted and recycled, but is uniformly sent to the oxidation liquid for hydrogen peroxide production, the impurities will affect the stability and other indicators of the final hydrogen peroxide product, affecting the normal production of hydrogen peroxide. In the method of Comparative Example 2, the hydrogen peroxide concentration in the final product is low, which can only be used in low-demand scenarios. In addition, it requires the additional installation of equipment such as coolers, resin towers, and filters, which increases the recycling cost.

[0053] It should be noted that some detailed steps of the operation are not described in this invention, but are prior art known to those skilled in the art, and therefore will not be repeated here. Furthermore, in this invention, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible secondary ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0054] It should be noted that the detailed structure of some devices is not described in this invention, but is prior art known to those skilled in the art, and therefore will not be elaborated here. In this invention, structures and devices not specifically limited can be purchased commercially, and those skilled in the art only need to install and operate them according to the accompanying instruction manual, without requiring any creative effort from those skilled in the art.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. In this invention, not all possible combinations of the various technical features in each embodiment or implementation are described. As long as the combinations of these technical features do not contradict each other, the various technical features in each embodiment or implementation can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for recovering and utilizing oxidation residue in hydrogen peroxide production, characterized in that, include: 1) Collect the oxidation residue from the upper column of the oxidation tower into the upper column residue storage tank, and periodically return it to the lower column of the oxidation tower to participate in the oxidation reaction of the hydrogenated liquid; 2) Collect the oxidation residue from the bottom of the oxidation tower into the bottom residue storage tank, take samples for testing regularly, and classify and recycle it according to the test results; In step 2), the specific steps for classification and recycling are as follows: if the sample indicators meet the recycling standards, the oxidation residue is discharged into the oxidation tank; if the sample indicators do not meet the recycling standards, the oxidation residue is discharged into the acidic wastewater tank; the sample indicators that meet the recycling standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥65%; The recycling method further includes: 3) Before the oxidation residue in the upper column residual liquid storage tank is returned to the lower column of the oxidation tower, a sample is taken for testing. If the sample indicators meet the recycling standards, the oxidation residue is sent to the lower column residual liquid storage tank, and then sampling, testing and recycling are carried out in accordance with 2). In section 3), the sample indicators that meet the recovery standards are as follows: hydrogen peroxide concentration ≥30%, stability ≥60%.

2. The method for recovering and utilizing oxidation residue in hydrogen peroxide production according to claim 1, characterized in that, In step 1), the frequency of returning the oxidation residue to the bottom of the oxidation tower is 2-3 times per day.

3. The method for recovering and utilizing oxidation residue in hydrogen peroxide production according to claim 1, characterized in that, In step 2), the sampling and testing frequency is 2-3 days / time.

4. The method for recovering and utilizing oxidation residue in hydrogen peroxide production according to claim 1, characterized in that, The volume ratio of the residual oxidation liquid to the oxidation liquid in the oxidation tank is 1:(50-500).

5. The method for recovering and utilizing oxidation residue in hydrogen peroxide production according to claim 1, characterized in that, In step 3), the volume ratio of the oxidized residual liquid from the upper column residual liquid storage tank that meets the recycling standards to the oxidized residual liquid in the lower column residual liquid storage tank is 1:(1-20).

6. The method for recovering and utilizing oxidation residue in hydrogen peroxide production according to any one of claims 1-5, characterized in that, The recycling method further includes: 4) the oxidation residue is mixed evenly with the oxidation liquid in the oxidation liquid tank, and then pumped into the extraction tower for extraction. The extract is then sent into the purification tower for purification, and finally qualified industrial-grade hydrogen peroxide products are obtained.

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