Method for separating organic matters in pentaerythritol mother liquor by utilizing air flotation equipment

Abstract

The invention relates to the technical field of recovery and comprehensive utilization of byproduct mother liquor in industrial production of pentaerythritol, and discloses a method for separating organic matters in pentaerythritol mother liquor by using air flotation equipment, which comprises the step of removing the organic matters in the pentaerythritol mother liquor by using the air flotation equipment to obtain impurity-removed mother liquor. According to the scheme, the oily impurities in the pentaerythritol mother liquor can be removed by adopting the air flotation equipment and utilizing the adsorption and mixing effects of tiny bubbles on the oily impurities, the impurity removal effect achieved by an existing extraction method is achieved, however, the air flotation equipment is adopted to separate organic matters in the pentaerythritol mother liquor, an extracting agent and a flocculating agent are not needed, and the cost is low. The energy consumption required for recovering the extracting agent is effectively reduced, and the impurity removal energy consumption and cost of the pentaerythritol mother liquor are effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of recovery and comprehensive utilization of by-product mother liquor of pentaerythritol in industrial production, and in particular to a method for separating organic matter in pentaerythritol mother liquor by utilizing air flotation equipment. Background Art

[0002] In industry, pentaerythritol is produced by condensation of formaldehyde and acetaldehyde as raw materials in the presence of an alkaline catalyst. A mother liquor containing pentaerythritol, dipentaerythritol, tripentaerythritol and sodium formate is produced as by-products. The pentaerythritol mother liquor needs to be separated to obtain pentaerythritol and sodium formate products.

[0003] At present, the extraction agent is conventionally used to extract pentaerythritol and other organic substances in the mother liquor, and the sodium formate is left in the water phase. The water phase is evaporated and crystallized to recover the sodium formate, and the extraction agent in the extract is recovered by distillation and recycled, and the remaining organic substances are incinerated for harmless treatment. The applicant recovers effective components such as pentaerythritol and sodium formate from the mother liquor by improving the control system of the extraction device. However, the prior art has the following technical problems:

[0004] (1) Since the extraction effect is affected by factors such as the concentration, temperature and flow rate of the extractant, in order to ensure the extraction effect, additional adjustment systems such as temperature and flow rate are added to the process, which invisibly increases the difficulty of monitoring by process personnel.

[0005] (2) At the same time, during the extraction process, although an extractant in which pentaerythritol and sodium formate are insoluble is selected, during the process production, a small amount of pentaerythritol and sodium formate will still be dissolved in the extractant and taken out of the system, resulting in the loss of effective components and reducing the yield of pentaerythritol product and sodium formate;

[0006] (3) After extraction, the extract phase consumes too much steam when regenerating the extractant using the sieve plate tower, increasing the energy consumption of the system;

[0007] (4) During the regeneration process, the extracted organic matter will be released due to the distillation and evaporation of the extractant, forming organic scaling. The scaling will gradually grow and become hardened, blocking the sieve holes of the sieve plate, causing the extraction regeneration tower to block liquid;

[0008] (5) When the liquid blocking is serious, small scale particles are carried out by the gas phase and enter the rear system, which will block the spray holes of the subsequent process equipment, making the process very difficult to handle. The only way to deal with the liquid blocking failure is to stop the corresponding process and replace the sieve plate of the extractant regeneration sieve plate tower passively. In addition, the degree of sieve plate blockage is uncontrollable, and the time point of the liquid blocking failure is uncontrollable, which increases the difficulty of process handling and the workload of inspection and maintenance.

[0009] In view of this, developing an efficient and low-cost method for separating organic matter in pentaerythritol mother liquor can not only effectively make up for the deficiencies of the existing technology, but also effectively separate and obtain the effective components in the pentaerythritol mother liquor, which is of great significance to improving the recovery and utilization effect of organic matter in the pentaerythritol mother liquor. Summary of the invention

[0010] The present invention aims to provide a method for separating organic matter in pentaerythritol mother liquor by using air flotation equipment, so as to solve the technical problem of excessive energy consumption in the prior art when extracting, recovering and separating organic matter in pentaerythritol mother liquor.

[0011] To achieve the above object, the present invention adopts the following technical scheme: a method for separating organic matter in pentaerythritol mother liquor by using flotation equipment, comprising removing organic matter in pentaerythritol mother liquor by using flotation equipment to obtain impurity-removed mother liquor.

[0012] Preferably, as an improvement, the method comprises the following steps:

[0013] Step 1: Preparation stage: prepare the flotation equipment and ensure that the flotation equipment operates normally;

[0014] Step 2: During the flotation equipment debugging phase, add desalted water to the flotation tank to the height of the slag collecting bucket, start the dissolved air pump, pre-adjust the dissolved air pressure, ventilate the dissolved air pump, and adjust the dissolved air pressure until uniform fine bubbles are generated;

[0015] Step 3, during the flotation and impurity removal stage, the pentaerythritol mother liquor is passed into the flotation tank, and the organic matter in the mother liquor is removed by flotation with fine bubbles. Part of the impurity-removed mother liquor obtained by the scraper is discharged from the drainage bucket, and part of the impurity-removed mother liquor is returned to the dissolved air pump, and after forming dissolved air water with air, it re-enters the flotation tank to remove the organic matter in the mother liquor by flotation.

[0016] Preferably, as an improvement, in step 2, the dissolved gas pressure is 0.35-0.50 MPa.

[0017] Preferably, as an improvement, in step 2, the water inlet pressure of the air dissolving pump is further adjusted, and the water inlet pressure is -0.01 to -0.03 MPa.

[0018] Preferably, as an improvement, in step 2, pre-adjusting the dissolved air pressure also includes debugging the water outlet state of the dissolved air pump, the steps are as follows: close the air inlet valve before starting the dissolved air pump, open the front water inlet valve and the rear water outlet valve of the dissolved air pump, and observe the water outlet for 1 to 2 minutes after starting the dissolved air pump until the water outlet is uniform.

[0019] Preferably, as an improvement, in step 2, the steps for pre-adjusting the dissolved air pressure are as follows: adjust the water outlet valve behind the pump to the pressure gauge display range of 0.35 to 0.50 MPa, then gradually adjust the water inlet valve before the pump to the vacuum gauge pressure of -0.01 to -0.03 MPa, then open the air inlet valve, and observe the appearance of milky white bubbles in the middle of the flotation tank to complete the pre-adjustment of the dissolved air pressure.

[0020] Preferably, as an improvement, in step 2, the particle size of the microbubbles is 20 to 40 um.

[0021] Preferably, as an improvement, in step three, the flow rate of the mother liquor entering the flotation tank is 5 to 8 t / h.

[0022] The principle of this scheme is:

[0023] The air dissolving pump of this scheme compresses the air and dissolves it into the solution. After the formed air-dissolved water enters the air flotation tank, the air dissolved in the solution is released from the mother liquor to form tiny bubbles. The tiny bubbles combine with the oily substances in the pentaerythritol mother liquor. Some tiny bubbles grow directly in the oily substances, making the specific gravity of the oily substances in the mother liquor smaller, until they float on the surface of the mother liquor and are scraped to the slag collecting hopper by the scraper, completing the removal of organic matter (such as oily impurities) in the pentaerythritol mother liquor. The impurity-removed mother liquor at the bottom of the air flotation tank is collected in the discharge hopper through the water collecting pipe and enters the next level of processing (such as distillation, rectification, etc.), so as to achieve the separation and recovery of the effective components in the pentaerythritol mother liquor.

[0024] The advantages of this solution are:

[0025] 1. Compared with the prior art which uses extraction technology to separate organic matter from pentaerythritol mother liquor, which consumes a lot of energy, this solution uses air flotation equipment to utilize the adsorption and miscibility effects of tiny bubbles on oily impurities, so as to achieve the removal of oily impurities from pentaerythritol mother liquor, and effectively reduce the energy consumption and cost of impurity removal of pentaerythritol mother liquor. The applicant found through long-term experiments that the organic impurity index of the impurity-removed mother liquor obtained by the treatment of this solution is equivalent to that of the impurity-removed mother liquor obtained by the treatment of the existing extraction technology, and the quality of the sodium formate product obtained by separation and purification of the impurity-removed mother liquor obtained by this solution is stable, and the quality of the sodium formate product is not reduced. It can be seen that the use of this solution to replace the extraction process greatly reduces the energy consumption of the extraction process, as well as the loss of pentaerythritol and sodium formate materials, improves the yield of pentaerythritol products, and helps to increase market competitiveness.

[0026] 2. This plan uses flotation equipment to remove impurities from the pentaerythritol mother liquor and disables the regeneration system of the extractant. On the one hand, it reduces steam consumption, lowers the production cost of pentaerythritol products, and saves energy and reduces consumption; on the other hand, no regeneration waste liquid is generated, reducing the discharge of wastewater and waste liquid from the system, and achieving green and high-quality development of the pentaerythritol plant; and the flotation device has fewer equipment and is easy to operate and maintain, reducing the labor intensity of on-site operations and the workload of inspection and maintenance.

[0027] 3. Compared with the existing flotation equipment that needs to add flocculants when treating sewage, this solution can achieve the removal of organic matter in pentaerythritol mother liquor without adding flocculants, further reducing the cost of flocculants, and can also avoid the use of flocculants to introduce new impurities into the pentaerythritol mother liquor, avoiding new impurity pollution, and thus more conducive to improving the purity of pentaerythritol and sodium formate separated from the subsequent pentaerythritol mother liquor. The inventor analyzed that the reason is that the organic impurities in this solution are mainly oily impurities, and this solution uses the mother liquor to return water to the dissolved air pump to form dissolved air water with air. During the process, the trace amount of oily impurities remaining in the mother liquor can fully contact and combine with the air, so that after the dissolved air water is released in the flotation tank, the bubbles and oily impurities can double-combine with the oily impurities in the mother liquor, thereby further improving the adhesion effect of the bubbles on the oily impurities, thereby effectively improving the impurity removal efficiency and impurity removal effect.

[0028] 4. This solution returns part of the pentaerythritol mother liquor treated by the flotation device to the dissolved air pump. The high-speed rotating pump impeller in the dissolved air pump mixes and stirs the liquid with the air. By limiting the dissolved air pressure, it is convenient to improve the dissolution efficiency between the air and the mother liquor, thereby effectively improving the removal effect of dissolved air water on the oily impurities in the pentaerythritol mother liquor. Specifically, the applicant found through long-term experiments that when the mother liquor and air are mixed under a dissolved air pressure of 0.35 to 0.5 MPa, the gas and the mother liquor can be fully dissolved, and the dissolution efficiency can reach 80 to 100%. After passing through the dissolved air release tube, the dissolved air water pressure is reduced to zero, and the air dissolved in the pentaerythritol mother liquor is released from the mother liquor to form tiny bubbles, which gather around the oily impurities, causing them to float and be removed, effectively improving the removal effect of the oily impurities in the pentaerythritol mother liquor. The applicant also tried other dissolved gas pressures and found that if the dissolved gas pressure is too low, the dissolution efficiency will be reduced, thereby reducing the removal effect of oily impurities; if the dissolved gas pressure is too high, not only will the dissolution efficiency not be further improved, but it will increase equipment requirements, increase energy consumption, and reduce economic benefits.

[0029] 5. In the equipment debugging stage, this solution first adjusts the water outlet state of the dissolved air pump, and then adjusts the dissolved air pressure until the bubbles meet the requirements, which effectively improves the equipment debugging efficiency and allows the equipment to enter the operating state as soon as possible. Specifically, the equipment debugging stage in this solution takes about 3 to 5 minutes, and the equipment startup waiting time is short, which is convenient for quickly starting the impurity removal of pentaerythritol mother liquor and improving the impurity removal efficiency of pentaerythritol mother liquor. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the front structural view of the air flotation device in an embodiment of the present invention.

[0031] Figure 2 Schematic diagram of the top view of the air flotation device in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following examples and experimental examples are conventional means well known to those skilled in the art, and the materials, reagents, etc. used can be obtained from commercial sources.

[0033] The figure marks in the drawings of the specification include: flotation tank 1, water inlet pipe 11, mother liquor feed valve 111, outer tank drain pipe 14, flotation liquid outlet valve 141, contact chamber 2, water collecting pipe 3, drainage bucket 4, water outlet pipe 41, return pipe 42, scraper 5, scraper blade 51, slag collecting bucket 6, slag outlet pipe 61, dissolved air pump 7, air inlet valve 71, pump front water valve 72, pump rear water outlet valve 73, gas-liquid separation tank 8.

[0034] Example 1

[0035] This scheme provides a method for separating organic matter from pentaerythritol mother liquor using an air flotation device, comprising: Figure 1 , Figure 2 The flotation equipment shown removes organic matter from the pentaerythritol mother liquor to obtain a decontaminated mother liquor. Specifically, the following steps are included:

[0036] Step 1: Preparation stage: prepare the flotation equipment and ensure that the flotation equipment operates normally;

[0037] As a reference, before using the air flotation device, check whether all parts of the equipment are well connected. Ensure that the mother liquid feed / discharge pipeline, slag discharge pipeline and auxiliary equipment (dissolved air pump 7, gas-liquid separation tank 8, dissolved air release pipe, scraper 5, etc.) are debugged and operate normally.

[0038] Step 2: During the flotation equipment debugging phase, add desalted water to the flotation tank 1 to the height of the slag collecting bucket 6, start the dissolved air pump 7, pre-adjust the dissolved air pressure, ventilate the dissolved air pump 7, and adjust the dissolved air pressure until uniform fine bubbles are generated;

[0039] The applicant discovered through long-term experiments that if tap water is used to replace desalted water, chloride ions and other metal ions will enter the system, causing new impurities to appear in the pentaerythritol and sodium formate products, while corroding stainless steel equipment and reducing the equipment life cycle; if pentaerythritol mother liquor is directly introduced, the mother liquor will be colored and the bubble formation cannot be observed, resulting in a deteriorated flotation effect and incomplete separation of oily impurities.

[0040] As a reference, the specific steps of the debugging stage are as follows: add desalted water to the flotation tank 1 to the height of the slag collecting bucket 6, close the air inlet valve 71, open the front water inlet valve 72 and the rear water outlet valve 73 of the dissolved air pump 7, start the dissolved air pump 7 and observe the water output for 1 to 2 minutes until the water output is uniform.

[0041] Subsequently, the outlet valve 73 after the pump is adjusted to a pressure gauge display range of 0.35 to 0.50 MPa (i.e., the dissolved gas pressure is 0.35 to 0.50 MPa). During the process, the pressure is increased and the flow rate is reduced if the adjustment is reduced. Then the inlet valve 72 before the pump is gradually adjusted to a vacuum gauge pressure of -0.01 to -0.03 MPa (i.e., the water inlet pressure is -0.01 to -0.03 MPa). During the process, the negative pressure is increased if the adjustment is reduced. The greater the negative pressure, the greater the steam-water ratio. Then, the inlet valve 71 is opened to observe the state of bubbles in the middle of the flotation tank 1, and the outlet valve 73 after the pump is adjusted to a pressure gauge display range of 0.35 to 0.50 MPa, and the inlet valve 72 before the pump is adjusted to a vacuum gauge pressure of -0.01 to -0.03 MPa, until milky white bubbles appear uniformly, and the dissolved gas pressure is pre-adjusted. As a reference, in this embodiment, the vacuum gauge is controlled to be -0.01 MPa and the dissolved gas pressure is 0.45 MPa. At this time, the milky white bubbles are fine bubbles with a particle size of 20 to 40 um.

[0042] Step 3, during the flotation and impurity removal stage, the pentaerythritol mother liquor is introduced into the flotation tank 1, and the organic matter in the mother liquor is removed by flotation with fine bubbles. Part of the impurity-removed mother liquor obtained by the scraper 5 is discharged from the drainage bucket 4, and part of the impurity-removed mother liquor is returned to the air dissolving pump 7, and after forming dissolved air water with air, it re-enters the flotation tank 1 to remove the organic matter in the mother liquor by flotation.

[0043] As a reference, the specific steps of the flotation impurity removal stage are as follows: after the water pressure of the dissolved air pump 7 is stable, open the mother liquid feed valve 111, the mother liquid enters the flotation tank 1 from the water inlet pipe 11, adjust the mother liquid flow rate to 5-8 t / h, the mother liquid and the dissolved air water contact in the contact chamber 2, the fine bubbles released by the dissolved air water adhere to the surface and inside of the oily impurities, forming "floating oil" floating to the liquid surface, and observe the flotation blooming at the same time. During normal operation, the operation of the flotation tank 1 should be checked frequently. When the floating oil (i.e., the oily impurities that rise due to air flotation) in the flotation tank 1 reaches a certain thickness, adjust the flotation liquid discharge valve 141 to reduce the flow rate of the liquid in the flotation tank 1 discharged from the outer tank drain pipe 14, so that the liquid level in the flotation tank 1 rises to the level of the slag collecting bucket 6, open the scraper 5 to scrape the oil, collect the floating oil in the slag collecting bucket 6, and then discharge it through the slag discharge pipe 61.

[0044] Part of the impurity removal mother liquor in the flotation tank 1 flows into the drainage bucket 4 along the water collecting pipe 3, and then flows into the air dissolving pump 7 along the return pipe 42, and returns to the flotation tank 1 after forming dissolved air water with air; and part of the impurity removal mother liquor in the drainage bucket 4 is discharged along the outlet pipe 41. The remaining impurity removal mother liquor in the flotation tank 1 is discharged along the outer tank drainage pipe 14 at the bottom.

[0045] Step 4: When stopping operation, the mother liquid feed valve 111 should be closed first, the air dissolving pump 7 and the scraper 5 should be operated for more than 10 minutes, and then the whole set of flotation equipment should be stopped.

[0046] Examples 2 to 3 and Comparative Examples 1 to 6 are basically the same as Example 1, except that the parameters of each stage are controlled differently. The differences in the parameters of each stage in Examples 1 to 3 and Comparative Examples 1 to 6 are detailed in Table 1.

[0047] Table 1 Differences in parameters at each stage in Examples 1 to 3 and Comparative Examples 1 to 6

[0048] Example Dissolved gas pressure / MPa Inlet water pressure / MPa Mother liquor inlet flow / t / h Example 1 0.45 -0.01 5 Example 2 0.35 -0.02 6 Example 3 0.5 -0.03 8 Comparative Example 1 0.3 -0.02 6 Comparative Example 2 0.6 -0.02 6 Comparative Example 3 0.45 -0.005 6 Comparative Example 4 0.45 -0.05 6 Comparative Example 5 0.45 -0.02 4 Comparative Example 6 0.45 -0.02 9

[0049] Comparative Example 7

[0050] The organic matter in the pentaerythritol mother liquor is removed by the existing extraction method. The current pentaerythritol mother liquor extractant is isobutyl alcohol, and the extraction ratio is controlled at 1 to 4. The steps are as follows:

[0051] First, prepare 80% to 90% isobutanol solution. After heating, the temperature of the extractant and mother liquor is raised to 80℃ to 90℃. They enter the extraction tank from both ends. After countercurrent mixing and clarification, the impurities in the pentaerythritol mother liquor are dissolved by the extractant. After the extract is regenerated in the regeneration tower, the isobutanol solution is returned to the system for recycling. The impurities dissolved by the extractant are taken out of the system through the waste liquid of the regeneration tower. The pentaerythritol mother liquor extraction system operates continuously to ensure the stability of the extraction effect.

[0052] The organic components in the pentaerythritol mother liquor before and after treatment in Examples 1 to 3 and Comparative Examples 1 to 7 of this scheme are shown in Table 2.

[0053] Table 2 Comparison of organic components in pentaerythritol mother liquor before and after treatment in Examples 1 to 3 and Comparative Examples 1 to 7

[0054]

[0055] Experimental data show that this scheme can remove oily impurities in pentaerythritol mother liquor by using flotation equipment and utilizing the adsorption and miscibility effects of tiny bubbles on oily impurities, thereby achieving the impurity removal effect achieved by extraction in Comparative Example 7. However, this scheme uses flotation equipment to separate organic matter in pentaerythritol mother liquor, which not only does not require an extractant, but also does not require a flocculant, effectively reducing the energy consumption required for recovering the extractant, and effectively reducing the energy consumption and cost of impurity removal of pentaerythritol mother liquor.

[0056] The applicant has found through long-term experiments that in the impurity removal process, the dissolved gas pressure, the water inlet pressure and the flow rate of the mother liquor into the flotation tank will significantly affect the impurity removal effect. Specifically, if the dissolved gas pressure is too low (such as in comparative example 1), bubbles cannot be formed due to the inability to discharge the dissolved gas, and the oily substance cannot float on the surface of the mother liquor through buoyancy, which reduces the impurity removal effect; and if the dissolved gas pressure is too high (such as in comparative example 2), the equipment will be damaged due to the excessive pressure on the dissolved gas pump; and the excessive pressure will also cause the uniformity of bubble release to decrease, thereby affecting the flotation effect of organic matter and reducing the impurity removal effect. If the water inlet pressure is too low (such as in comparative example 3), the oily substance will not be separated thoroughly due to the small flow rate, reducing the impurity removal effect; if the water inlet pressure is too high (such as in comparative example 4), the dissolved gas pump will be overloaded due to the excessive flow rate, damaging the equipment; and the excessive pressure will also cause the uniformity of bubble release to decrease, thereby affecting the flotation effect of organic matter and reducing the impurity removal effect. If the mother liquor inlet flow rate is too slow (such as in comparative example 5), the system liquid level will be unbalanced due to the reduced processing volume, thereby reducing the mother liquor processing efficiency; and if the mother liquor inlet flow rate is too fast (such as in comparative example 6), some organic matter will be discharged before being removed, thereby reducing the separation efficiency of organic matter in the mother liquor, thereby affecting the purity of the subsequently obtained pentaerythritol and sodium formate products.

[0057] In summary, this scheme uses flotation equipment to replace the extraction process to separate organic matter from pentaerythritol mother liquor, which not only greatly reduces the reagent cost, energy consumption and loss of pentaerythritol and sodium formate materials in the extraction process, but also improves the yield of pentaerythritol product and helps to increase market competitiveness.

[0058] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for separating organic matter from pentaerythritol mother liquor using an air flotation device, characterized in that: The method comprises adopting air flotation equipment to remove organic matter in pentaerythritol mother liquor to obtain impurity-removed mother liquor.

2. The method for separating organic matter from pentaerythritol mother liquor by using air flotation equipment according to claim 1, characterized in that: The steps include: Step 1: Preparation stage: prepare the flotation equipment and ensure that the flotation equipment operates normally; Step 2: During the flotation equipment debugging phase, add desalted water to the flotation tank to the height of the slag collecting bucket, start the dissolved air pump, pre-adjust the dissolved air pressure, ventilate the dissolved air pump, and adjust the dissolved air pressure until uniform fine bubbles are generated; Step 3, during the flotation and impurity removal stage, the pentaerythritol mother liquor is passed into the flotation tank, and the organic matter in the mother liquor is removed by flotation with fine bubbles. Part of the impurity-removed mother liquor obtained by the scraper is discharged from the drainage bucket, and part of the impurity-removed mother liquor is returned to the dissolved air pump, and after forming dissolved air water with air, it re-enters the flotation tank to remove the organic matter in the mother liquor by flotation.

3. A method for separating organic matter from pentaerythritol mother liquor using air flotation equipment according to claim 2, characterized in that: In step 2, the dissolved gas pressure is 0.35-0.50 MPa.

4. A method for separating organic matter from pentaerythritol mother liquor by using air flotation equipment according to claim 2, characterized in that: In step 2, the water inlet pressure of the air dissolving pump is also adjusted, and the water inlet pressure is -0.01 to -0.03 MPa.

5. The method for separating organic matter from pentaerythritol mother liquor by using air flotation equipment according to claim 2, characterized in that: In step 2, pre-adjusting the dissolved air pressure also includes debugging the water outlet state of the dissolved air pump, and the steps are as follows: close the air inlet valve before starting the dissolved air pump, open the front water inlet valve and the rear water outlet valve of the dissolved air pump, and observe the water outlet for 1 to 2 minutes after starting the dissolved air pump until the water outlet is uniform.

6. The method for separating organic matter from pentaerythritol mother liquor by using air flotation equipment according to claim 2, characterized in that: In step 2, the steps for pre-adjusting the dissolved air pressure are as follows: adjust the water outlet valve behind the pump to the pressure gauge display range of 0.35~0.50MPa, then gradually adjust the water inlet valve before the pump to the vacuum gauge pressure of -0.01~-0.03MPa, then open the air inlet valve, and observe the appearance of milky white bubbles in the middle of the flotation tank to complete the pre-adjustment of the dissolved air pressure.

7. The method for separating organic matter from pentaerythritol mother liquor by using air flotation equipment according to claim 2, characterized in that: In step 2, the particle size of the microbubbles is 20-40 um.

8. The method for separating organic matter from pentaerythritol mother liquor by using air flotation equipment according to claim 2, characterized in that: In step three, the flow rate of the mother liquor into the flotation tank is 5 to 8 t / h.

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