A system and method for treating heat treatment wastewater containing PAG quenching liquid

Abstract

The present invention proposes a heat treatment wastewater treatment system and method containing PAG quenching liquid, including: an evaporation tank for containing heat treatment wastewater; a separation mechanism, including a lifting device and a sprayer, wherein the lifting device is used to lift the tempered high-temperature forgings to the top of the evaporation tank, and the sprayer is used to repeatedly spray the heat treatment wastewater in the evaporation tank onto the surface of the high-temperature forgings for water vapor evaporation separation; a collection tank, which is connected to the evaporation tank, is used to collect the concentrated PAG quenching liquid in the evaporation tank. Compared with the heat treatment wastewater treatment process in the prior art, the present invention does not require the use of complex equipment, and directly evaporates and concentrates the heat treatment wastewater with the tempered forgings on the existing heat treatment production line. The high-concentration PAG quenching liquid after evaporation and concentration can also be reused. Compared with the traditional wastewater chemical treatment method, it has the advantages of no need to add chemicals, low operating cost, simple system, and energy reduction and emission reduction.

Description

Technical Field

[0001] The invention relates to the field of heat treatment wastewater treatment, and in particular to a heat treatment wastewater treatment system and method containing PAG quenching liquid. Background Art

[0002] With the formal promulgation and implementation of the new "Water Pollution Prevention and Control Law", industrial enterprises are facing more stringent wastewater discharge standards. PAG quenching liquid is a water-based quenching medium. It is the most common and best-used water-based quenching medium currently used at home and abroad. At present, most companies' heat treatment production lines use double-liquid (PAG and water) single-tank equipment process design. In particular, in the process of switching PAG quenching liquid to clean water quenching liquid, a certain amount of PAG quenching liquid will remain in the equipment pipeline and quenching tank. This will cause the quenching liquid to switch to produce heat treatment wastewater containing PAG water-based quenching medium. The COD pollutant concentration is generally as high as 5000mg / L, which is 5 to 8 times the COD of the inlet water designed by the chemical oxidation wastewater treatment system commonly used by enterprises. Direct discharge cannot completely digest and degrade organic matter, and will cause pollution to water resources and soil, threatening the environment and human health. Therefore, heat treatment wastewater is usually separated and treated, that is, as much PAG water-based quenching medium as possible is separated from the wastewater to make the wastewater meet the discharge standards.

[0003] In some prior arts, such as the Chinese patent with publication number CN206940484U, a quenching and cooling wastewater separation device is disclosed, which separates water and oil by specific gravity. However, after the workpiece is quenched and cooled, the temperature of the aqueous solution of the quenching liquid containing the PAG water-based quenching medium is usually close to room temperature. At this time, the PAG water-based quenching medium is mainly composed of PAG polymer. After the quenching liquid is cooled down, the PAG polymer quickly dissolves back into the quenching liquid, making it impossible to separate the PAG water-based quenching medium and water.

[0004] In addition, in the prior art, Chinese patent CN104496082A discloses a separation and treatment device for heat treatment wastewater and a wastewater treatment method, which separates the oily substances in the wastewater through precipitation, demulsification, adsorption, ultrafiltration and nanofiltration, extracts, removes impurities and reuses them, and filters and purifies the non-oily substances in the water. Finally, the treated water can be recycled or directly discharged. The above scheme requires a large amount of chemical agents to be put into the separation treatment, which is complicated in process, long in treatment cycle and high in cost. At the same time, the separation treatment of the above patent is aimed at oily substances, and is not suitable for the treatment of wastewater containing PAG water-based quenching medium. Summary of the invention

[0005] In view of this, the present invention proposes a system and method for treating heat treatment wastewater containing PAG quenching liquid to solve the problem that the heat treatment wastewater treatment system in the prior art cannot perform simple, effective, energy-saving and emission-reducing recycling treatment on wastewater containing PAG quenching liquid.

[0006] The technical solution of the present invention is achieved in this way:

[0007] The present invention provides a heat treatment wastewater treatment system containing PAG quenching liquid, comprising:

[0008] Evaporation tanks, used to hold thermal treatment wastewater;

[0009] The separation mechanism includes a lifting device and a sprayer, wherein the lifting device is used to lift the tempered high-temperature forgings to the top of the evaporation tank, and the sprayer is used to repeatedly spray the heat treatment wastewater in the evaporation tank onto the surface of the high-temperature forgings to evaporate and separate water and gas;

[0010] The collecting tank is connected to the evaporating tank and is used for collecting the concentrated PAG quenching liquid in the evaporating tank.

[0011] On the basis of the above technical solution, preferably, it also includes a sedimentation storage tank, wherein the sedimentation storage tank is used to collect heat treatment wastewater, and the sedimentation storage tank is connected to the evaporation tank through a flow control valve.

[0012] Furthermore, preferably, a desolventizing tank is also included, which is respectively connected to the evaporation tank and the collection tank, and is used to heat the aqueous solution transported to the desolventizing tank to desolvent the PAG quenching liquid and water in the aqueous solution.

[0013] On the basis of the above technical solution, preferably, the separation mechanism further comprises an evaporation chamber, the evaporation chamber is movably arranged just above the evaporation tank, and an operating space for a lifting device to enter is provided between the evaporation chamber and the evaporation tank.

[0014] Further, preferably, the separation mechanism further comprises an exhaust device installed on the evaporation chamber, and the exhaust device is used to discharge water vapor evaporated from the high-temperature forgings from the evaporation chamber.

[0015] On the basis of the above technical solution, preferably, a first concentration sensor is provided inside the evaporation tank, and the first concentration sensor is used to detect the concentration of the PAG quenching liquid in the aqueous solution in the evaporation tank.

[0016] Further, preferably, a temperature sensor and a second concentration sensor are provided inside the desolventizing tank, the temperature sensor is used to detect the temperature of the aqueous solution inside the desolventizing tank, and the second concentration sensor is used to detect the concentration of the PAG quenching liquid in the aqueous solution in the desolventizing tank.

[0017] The present invention also discloses a method for treating heat treatment wastewater containing PAG quenching liquid, using the above-mentioned heat treatment wastewater treatment system containing PAG quenching liquid, and the steps are:

[0018] S1, passing the heat treatment wastewater generated by switching the quenching liquid into the evaporation tank;

[0019] S2. The tempered high-temperature forgings are hoisted above the evaporation tank, and the heat treatment wastewater in the evaporation tank is continuously sprayed onto the surface of the high-temperature forgings, and the water vapor in the wastewater is repeatedly evaporated by the high-temperature forgings;

[0020] S3, when the concentration of the PAG quenching liquid in the heat treatment wastewater in the evaporation tank reaches a first predetermined value, the aqueous solution containing the PAG quenching liquid is pumped into the desolventizing tank for concentration;

[0021] S4, using a high temperature forging to repeatedly heat and evaporate the aqueous solution in the desolventizing tank, and desolventize the PAG quenching liquid and water in the aqueous solution;

[0022] S5. When the concentration of the PAG quenching liquid in the aqueous solution in the desolventizing tank reaches a second predetermined value, the PAG quenching liquid at the bottom of the desolventizing tank is recovered through the collecting tank for reuse.

[0023] Based on the above technical solution, preferably, the high-temperature forging first evaporates the water vapor in the evaporation tank, and then uses the waste heat of the high-temperature forging to heat the aqueous solution in the desolventizing tank to desolventize the PAG quenching liquid and water in the aqueous solution.

[0024] Based on the above technical solution, preferably, in step S2, after the high-temperature forgings evaporate water vapor above the evaporation tank for a certain period of time, they can be immersed in the evaporation tank through a lifting device to dissolve the PAG quenching liquid attached to the high-temperature forgings back into the aqueous solution.

[0025] Further, preferably, in step S2, heat-treated wastewater may be gradually added to the evaporation tank.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The heat treatment wastewater treatment system containing PAG quenching liquid disclosed in the present invention provides an evaporation tank and a collection tank that are interconnected, and the heat treatment wastewater generated by switching the quenching liquid is introduced into the evaporation tank. A separation mechanism is provided on the evaporation tank, and a high-temperature forging that has been tempered is lifted to the evaporation tank by a lifting device. The heat treatment wastewater in the evaporation tank can be repeatedly sprayed onto the surface of the high-temperature forging by a sprayer. In the wastewater sprayed onto the surface of the high-temperature forging, a portion of the water vapor in the wastewater evaporates and separates under high temperature conditions, and the unevaporated wastewater falls into the evaporation tank and is cyclically evaporated under the action of the evaporator, thereby gradually evaporating and separating the water in the aqueous solution in the evaporation tank, thereby increasing the concentration of the PAG quenching liquid in the aqueous solution. When the PAG quenching liquid in the aqueous solution reaches a recoverable concentration, it is collected through a collection tank, so that it can be reused when the forgings need the PAG quenching liquid for quenching. Compared with the heat treatment wastewater treatment process in the prior art, the present invention does not require the use of complex equipment, and directly uses the forgings tempered on the existing heat treatment production line to evaporate and concentrate the heat treatment wastewater. The high-concentration PAG quenching liquid after evaporation and concentration can also be reused. Compared with the traditional wastewater chemical treatment method, it has the advantages of no need to add chemicals, low operating cost, simple system, and energy reduction and emission reduction;

[0028] (2) By setting up a precipitation storage tank and connecting the precipitation storage tank with the evaporation tank through a flow control valve, the heat treatment wastewater can be added to the evaporation tank in time during the evaporation and concentration process of the evaporation tank, so as to avoid the evaporator being blocked when the concentration of the PAG quenching liquid is too high when the fixed volume of the aqueous solution in the evaporation tank is evaporated and concentrated. On the one hand, the aqueous solution cannot be effectively sprayed on the surface of the forging, and on the other hand, the PAG polymer in the sprayed PAG quenching liquid will accumulate too much on the surface of the forging, reducing the concentration of the PAG quenching liquid in the evaporation tank;

[0029] (3) By setting a desolventizing tank connected to the evaporation tank, the aqueous solution containing a certain concentration of PAG quenching liquid after evaporation and concentration in the evaporation tank can be pumped into the desolventizing tank, and the aqueous solution can be heated. On the one hand, the heated aqueous solution can be concentrated again to increase the concentration of the PAG quenching liquid in the aqueous solution, and the evaporation tank can be used for concentration to improve the concentration efficiency of the PAG quenching liquid in the aqueous solution; on the other hand, the PAG quenching liquid and water in the aqueous solution can be desolventized, so that the high-concentration PAG can be easily collected by the collection tank;

[0030] (4) By setting an evaporation chamber just above the evaporation tank, the high-temperature forgings can be kept in a heat-insulating environment in the operating space between the evaporation chamber and the evaporation tank, thereby preventing the high-temperature forgings from being affected by the external environment and accelerating their own cooling, thereby improving the efficiency of using the residual heat of the forgings after tempering;

[0031] (5) By installing an exhaust device on the evaporation chamber, the steam in the evaporation chamber can be discharged in time to prevent the steam from accumulating in the evaporation chamber and falling into the evaporation tank, thereby reducing the concentration of PAG quenching liquid in the aqueous solution;

[0032] (6) By arranging a first concentration sensor inside the evaporation tank, the concentration of the PAG quenching liquid in the aqueous solution in the evaporation tank can be detected in real time. When the concentration of the PAG quenching liquid in the aqueous solution reaches a certain value, the aqueous solution containing a certain concentration of the PAG quenching liquid after evaporation and concentration in the evaporation tank can be pumped into the desolventizing tank in time through the desolventizing tank, and the aqueous solution can be heated to avoid the evaporation operation being blocked due to excessive concentration in the evaporation tank;

[0033] (7) By arranging a temperature sensor and a second concentration sensor inside the desolventizing tank, the temperature of the aqueous solution in the desolventizing tank and the concentration of the PAG quenching liquid in the aqueous solution can be detected in real time, so that after the PAG quenching liquid is desolventized, when its concentration reaches a level that can be recovered and reused, it can be recovered in time by the collection tank.

[0034] (8) By allowing the high-temperature forgings to evaporate the waste water in the evaporation tank first, and then using the waste heat of the high-temperature forgings to heat the aqueous solution in the desolventizing tank to achieve the desolventizing of PAG polymer and water in the PAG quenching liquid, the waste heat of the high-temperature forgings after tempering on the heat treatment production line can be fully and reasonably utilized, thereby improving the concentration and desolventizing efficiency of the PAG quenching liquid in the aqueous solution;

[0035] (9) After the high-temperature forgings have been exposed to water vapor evaporation for a certain period of time above the evaporation tank, the high-temperature forgings are immersed in the evaporation tank through a lifting device. The PAG polymer attached to the high-temperature forgings can be dissolved back into the aqueous solution to avoid excessive accumulation of PAG polymer on the surface of the forgings, thereby reducing the concentration of PAG quenching liquid in the evaporation tank.

[0036] (10) By gradually adding heat treatment wastewater to the evaporation tank during the evaporation concentration process, the heat treatment wastewater can be treated continuously, thereby achieving efficient recovery of high-concentration PAG quenching liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 It is a schematic plan view of the structure of the heat treatment wastewater treatment system containing PAG quenching liquid disclosed in the present invention;

[0039] Figure 2 It is a schematic flow chart of the method for treating heat treatment wastewater containing PAG quenching liquid disclosed in the present invention;

[0040] Reference numerals:

[0041] 1. Evaporation tank; 2. Separation mechanism; 21. Lifting device; 22. Sprayer; 3. Collection tank; 4. Sedimentation storage tank; 41. Flow control valve; 5. Desolventizing tank; 23. Evaporation chamber; 24. Exhaust device; S. High-temperature forgings. DETAILED DESCRIPTION

[0042] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] As for the prior art, in the heat treatment production line, quenching liquid is usually selected as the quenching cooling medium. The quenching liquid is more commonly PAG quenching liquid or clean water. In some enterprises' heat treatment production lines, there is a design in which double quenching liquid pipelines share a quenching tank, that is, some forgings with higher requirements use PAG quenching liquid for quenching, and some forgings with lower requirements use clean water for quenching. In the process of switching the PAG quenching liquid to the clean water quenching liquid, a certain amount of PAG quenching liquid will remain in the equipment pipeline and the quenching tank, which will cause the quenching liquid to switch to produce heat treatment wastewater containing PAG water-based quenching medium. The COD pollutant concentration in this part of the heat treatment wastewater is relatively high and needs to be treated. Usually, the heat treatment wastewater is separated and treated, that is, as much PAG water-based quenching medium as possible is separated from the wastewater to make the wastewater meet the composite discharge standard.

[0044] However, the related art only discloses the separation process of quenching oil and water, and does not disclose the wastewater separation process containing PAG quenching liquid.

[0045] The present invention solves the problem that in the actual production process, when the PAG quenching liquid is switched to the clean water quenching liquid, heat treatment wastewater containing the PAG water-based quenching medium will be generated after the quenching liquid is switched. Therefore, the present invention proposes a heat treatment wastewater treatment system containing the PAG quenching liquid to solve the above problem.

[0046] like Figure 1 As shown, the heat treatment wastewater treatment system containing PAG quenching liquid disclosed in the embodiment of the present invention includes an evaporation tank 1, a separation mechanism 2 and a collection tank 3.

[0047] Among them, the evaporation tank 1 is arranged on the heat treatment production line to receive and contain the heat treatment wastewater. In this embodiment, the quenching liquid is switched on the heat treatment production line, and the heat treatment wastewater generated after quenching is completed can be transferred to the evaporation tank 1 after filtering.

[0048] The separation mechanism 2 includes a lifting device 21 and a sprayer 22. The lifting device 21 is used to lift the high-temperature forging S that has completed tempering to just above the evaporation tank 1. In this embodiment, the lifting device 21 can be an overhead crane, a crane, or other equipment used for lifting on the heat treatment production line. These equipment can be used to perform the forging heat treatment process simultaneously on the heat treatment production line.

[0049] The sprayer 22 is used to repeatedly spray the heat treatment wastewater in the evaporation tank 1 onto the surface of the high-temperature forging S for water vapor evaporation and separation. Specifically, in this embodiment, the sprayer 22 is composed of a spray pump and a spray pipe. The spray pump sucks the heat treatment wastewater in the evaporation tank 1 and sprays it through the spray head at the end of the spray pipe to spray the heat treatment wastewater onto the surface of the high-temperature forging S that has been tempered. In the high-temperature environment, part of the water vapor in the wastewater sprayed onto the surface of the high-temperature forging S evaporates and separates in the wastewater, and the unevaporated wastewater falls into the evaporation tank 1, and then circulates and evaporates under the action of the evaporator, thereby gradually evaporating and separating the water in the aqueous solution in the evaporation tank 1, thereby increasing the concentration of the PAG quenching liquid in the aqueous solution.

[0050] Because the PAG quenching liquid is composed of PAG polymer, the temperature of the high-temperature forging needs to meet the cloud point of the PAG polymer. When the temperature reaches above 74°, the PAG polymer will dissolve in the solution, thereby achieving the separation of the PAG polymer and the solution, thereby increasing the concentration of the PAG quenching liquid in the aqueous solution.

[0051] When the PAG quenching liquid in the aqueous solution reaches a recoverable concentration, it is collected by the collecting tank 3, so that it can be reused when the forging needs the PAG quenching liquid for quenching. In this embodiment, a suction pump can be connected between the collecting tank 3 and the evaporation tank 1.

[0052] It is worth noting that the temperature of high-temperature forgings S after tempering on the heat treatment production line is usually 400-500℃, and these high-temperature forgings S after tempering are usually cooled by air or oil. These production processes mean energy waste and are not in line with the concept of energy conservation and emission reduction.

[0053] Based on this, the present invention directly uses the forgings that have been tempered on the existing heat treatment production line to evaporate and concentrate the heat treatment wastewater, fully utilizing the waste heat of the high-temperature forgings S after tempering to continue production operations, and the high-concentration PAG quenching liquid evaporated and concentrated from the high-temperature forgings S after tempering can also be reused. Compared with traditional wastewater chemical treatment methods, it has the advantages of no need to add chemicals, low operating costs, a simple system, and energy reduction and emission reduction.

[0054] Since the volume of the heat treatment wastewater in the evaporation tank 1 is fixed, the concentration of the PAG quenching liquid in the aqueous solution in the evaporation tank 1 gradually increases during the continuous evaporation and concentration process. The main component of the PAG quenching liquid is PAG polymer. When the concentration of the PAG quenching liquid is too high, the evaporator will be blocked, reducing the efficiency of spraying the aqueous solution onto the forging surface, and causing the evaporator to malfunction and be unable to continue to be used.

[0055] To this end, this embodiment sets a precipitation storage tank 4, and connects the precipitation storage tank 4 with the evaporation tank 1 through a flow control valve 41. During the evaporation and concentration process of the evaporation tank 1, the heat treatment wastewater can be replenished in the evaporation tank 1 in time to avoid the evaporator being blocked when the concentration of the PAG quenching liquid is too high when the fixed volume of the aqueous solution in the evaporation tank 1 is evaporated and concentrated. At the same time, it can also avoid excessive accumulation of PAG polymer sprayed into the PAG quenching liquid on the surface of the forging, thereby reducing the concentration of the PAG quenching liquid in the evaporation tank 1.

[0056] In this embodiment, the flow control valve 41 can be opened within a certain period of time to inject a certain volume of heat treatment wastewater into the evaporation tank 1 through the sedimentation storage tank 4. Of course, the flow control valve 41 can also be opened according to the concentration of the PAG quenching liquid in the aqueous solution in the evaporation tank 1. That is, when the concentration of the PAG quenching liquid in the aqueous solution is higher than a certain value and there is evaporator blockage, the flow control valve 41 can be opened to inject a certain volume of heat treatment wastewater into the evaporation tank 1.

[0057] In addition, it is worth noting that the sedimentation storage tank 4 in this embodiment can inject a large amount of heat treatment wastewater at one time. The sedimentation storage tank 4 can precipitate the oxide scale or impurities in the wastewater to the bottom of the tank during the static process, thereby reducing the impurity and oxide scale content in the heat treatment wastewater entering the evaporation tank 1, and preventing these substances from blocking the evaporator.

[0058] Although adding a sedimentation storage tank 4 upstream of the evaporation tank 1 can solve the problem of evaporator blockage caused by the increase in the concentration of PAG quenching liquid in the aqueous solution, new problems will arise. Specifically, when the concentration of PAG quenching liquid in the aqueous solution in the evaporation tank 1 increases, its concentration is not high. If the PAG quenching liquid is collected through the collection tank 3 at this time, it may not comply with the recycling principle. If the evaporation operation is continued in the evaporation tank 1, although the concentration can be increased, the evaporator blockage problem will be faced. Adding heat treatment wastewater to the evaporation tank 1 will reduce the concentration of the PAG quenching liquid.

[0059] To this end, in this embodiment, a desolventizing tank 5 connected to the evaporation tank 1 is provided, so that the aqueous solution containing a certain concentration of PAG quenching liquid after evaporation and concentration in the evaporation tank 1 can be pumped into the desolventizing tank 5, and the aqueous solution is heated. On the one hand, the heated aqueous solution can be concentrated again to increase the concentration of the PAG quenching liquid in the aqueous solution, and can cooperate with the evaporation tank 1 to concentrate and improve the concentration efficiency of the PAG quenching liquid in the aqueous solution; on the other hand, the PAG quenching liquid and water in the aqueous solution can be desolventized, so that the high-concentration PAG can be easily collected by the collection tank 3.

[0060] It is worth noting that when the aqueous solution in the evaporation tank 1 is concentrated and its PAG quenching liquid concentration reaches a certain value, the aqueous solution containing a certain concentration of PAG quenching liquid after evaporation and concentration in the evaporation tank 1 is pumped into the desolventizing tank 5 through a suction pump. At this time, the heat treatment wastewater can be supplemented into the evaporation tank 1 through the precipitation storage tank 4, so that the evaporation tank 1 can continue to perform evaporation and concentration operations to meet the continuity of wastewater treatment.

[0061] It is worth noting that the heating of the aqueous solution in the desolventizing tank 5 is also achieved by the waste heat of the high-temperature forging S after tempering. The high-temperature forging S after tempering can be immersed in the desolventizing tank 5 for heating the aqueous solution through the lifting device 21. Once the liquid temperature around the high-temperature forging S rises above the turbidity point of the solution, the PAG polymer in the PAG quenching liquid is desolventized from the solution, suspended in the quenching liquid in the form of fine liquid droplets, and then slowly precipitated, thereby achieving the desolventization of the PAG polymer and water in the PAG quenching liquid.

[0062] In this embodiment, since the high-temperature forging S after tempering is lifted to the top of the evaporation tank 1 by the lifting device 21, the high-temperature forging S is in contact with the external environment during the evaporation process, and its own cooling will be accelerated, thereby reducing the utilization efficiency of the remaining heat.

[0063] To this end, in this embodiment, an evaporation chamber 23 is arranged directly above the evaporation tank 1, and an operating space is formed between the evaporation chamber 23 and the evaporation tank, so that the high-temperature forging S can be placed in a heat-insulating environment in the operating space between the evaporation chamber 23 and the evaporation tank 1, thereby preventing the high-temperature forging S from being affected by the external environment and accelerating its own cooling, thereby improving the efficiency of using the residual heat of the forging after tempering.

[0064] As some embodiments, the evaporation chamber 23 can be configured as two symmetrical covers, which are horizontally arranged on both sides of the evaporation tank 1, and can be relatively translated or relatively separated. When the lifting device 21 lifts the high-temperature forging S to the top of the evaporation tank 1, the two covers are closed together to form a complete evaporation chamber 23. The evaporation chamber 23 and the evaporation tank 1 are closed, so that the high-temperature forging S is placed in the operating space between the evaporation chamber 23 and the evaporation tank 1. The high-temperature forging S can reduce its own heat loss in the closed space.

[0065] To achieve the discharge of the steam in the above-mentioned operation space, in this embodiment, an exhaust device 24 is provided on the evaporation chamber 23, which can timely discharge the steam in the evaporation chamber 23, avoid the steam from accumulating in the evaporation chamber 23 and falling into the evaporation tank 1, and reduce the concentration of the PAG quenching liquid in the aqueous solution. In this embodiment, the exhaust device 24 includes an exhaust pipe and an air bleed fan, one end of the exhaust pipe is connected to the top of the evaporation chamber 23, and the other end extends outside the workshop, and the air bleed fan discharges the steam in the above-mentioned operation space.

[0066] As some preferred embodiments, by arranging a first concentration sensor (not shown in the figure) inside the evaporation tank 1, the concentration of the PAG quenching liquid in the aqueous solution in the evaporation tank 1 can be detected in real time. When the concentration of the PAG quenching liquid in the aqueous solution reaches a certain value, the aqueous solution containing a certain concentration of PAG quenching liquid after evaporation and concentration in the evaporation tank 1 can be promptly pumped into the desolventizing tank 5 through the desolventizing tank 5, and the aqueous solution can be heated to avoid obstruction of the evaporation operation caused by excessive concentration in the evaporation tank 1. In addition, it is worth noting that after the aqueous solution in the evaporation tank 1 is pumped into the desolventizing tank 5, the heat-treated wastewater in the sedimentation storage tank 4 can be injected into the evaporation tank 1 through the flow control valve 41 to a certain volume to meet the continuous evaporation and concentration operation of the evaporation tank 1.

[0067] As other embodiments, by providing a temperature sensor (not shown in the figure) and a second concentration sensor (not shown in the figure) inside the desolventizing tank 5, the temperature of the aqueous solution in the desolventizing tank 5 and the concentration of the PAG quenching liquid in the aqueous solution can be detected in real time, so that after the PAG quenching liquid is desolventized, when its concentration reaches a level that can be recycled and reused, it can be promptly recovered by the collecting tank 3. In this embodiment, when the temperature sensor detects that the temperature of the aqueous solution in the desolventizing tank is lower than 74°, it is necessary to drive the lifting device to lift new forgings again through signal feedback to ensure that the polymer in the PAG quenching liquid does not dissolve back into the aqueous solution.

[0068] See attached Figure 2 As shown, the present invention also discloses a method for treating heat treatment wastewater containing PAG quenching liquid, using the above-mentioned heat treatment wastewater treatment system containing PAG quenching liquid, and the steps are:

[0069] S1, passing the heat treatment wastewater generated by switching the quenching liquid into the evaporation tank 1;

[0070] In this embodiment, the temperature of the heat-treated wastewater introduced into the evaporation tank is close to room temperature.

[0071] S2, hoisting the tempered high-temperature forging S above the evaporation tank 1, continuously spraying the heat treatment wastewater in the evaporation tank 1 onto the surface of the high-temperature forging S, and repeatedly evaporating the water vapor in the wastewater by using the high-temperature forging S;

[0072] In step S2, the incoming material temperature of the high-temperature forging S is 400-500°C. The heat treatment wastewater is continuously sprayed onto the high-temperature forging S to evaporate the water vapor in the heat treatment wastewater. During the evaporation process, the temperature of the high-temperature forging S will gradually decrease. When the temperature of the high-temperature forging S is lower than 74°C, it is necessary to replace it with a new high-temperature forging S, because the PAG polymer will dissolve from the aqueous solution at a temperature higher than 74°C, so that the water in the aqueous solution will evaporate under high temperature conditions, and the concentration of the PAG quenching liquid formed by the PAG polymer will increase. When the temperature of the high-temperature forging S is lower than 74°C, the cloud point of the PAG polymer cannot be reached. At this time, the PAG polymer will dissolve back into the aqueous solution.

[0073] S3, when the concentration of the PAG quenching liquid in the heat treatment wastewater in the evaporation tank 1 reaches a first predetermined value, the aqueous solution containing the PAG quenching liquid is pumped into the desolventizing tank 5 for concentration;

[0074] In this embodiment, the first predetermined value is the concentration ratio of the PAG quenching liquid in the aqueous solution. The first predetermined value is usually 2%-5%. This concentration value does not meet the conditions for recycling the PAG quenching liquid.

[0075] S4, using the high temperature forging S to repeatedly heat the aqueous solution in the desolventizing tank 5, and desolventizing the PAG quenching liquid and water in the aqueous solution;

[0076] In this embodiment, the aqueous solution is repeatedly heated by the tempered forgings, and the temperature of the high-temperature forgings needs to be higher than 74°C, preferably above 100°C, so that the PAG polymer can be effectively desolvated in the aqueous solution during the heating process. When the temperature in the desolvation tank is lower than 74°C, the high-temperature forgings need to be replaced to meet the desolvation conditions, and continuous heating can meet the concentration ratio of the PAG quenching liquid in the aqueous solution.

[0077] S5. When the concentration of the PAG quenching liquid in the aqueous solution in the desolventizing tank 5 reaches a second predetermined value, which is greater than the first predetermined value, the PAG quenching liquid at the bottom of the desolventizing tank 5 is recovered through the collecting tank 3 for reuse.

[0078] In this embodiment, the aqueous solution in the desolventizing tank is heated by the high-temperature forging S. On the one hand, desolventizing is satisfied, and on the other hand, the concentration ratio of the PAG quenching liquid in the aqueous solution can be increased. The concentration of the PAG quenching liquid in this embodiment reaches the second predetermined value. Specifically, the concentration of the PAG quenching liquid is required to reach more than 5%, which can meet the recycling standard. Of course, a higher concentration standard can be determined by actual production, which only requires controlling the heating time of the aqueous solution in the desolventizing tank.

[0079] As some preferred implementation methods, in order to fully and reasonably utilize the residual heat of the high-temperature forging S after tempering, this embodiment enables the high-temperature forging S to first evaporate the water vapor in the aqueous solution in the evaporation tank 1, and then use the residual heat of the high-temperature forging S to heat the aqueous solution in the desolventizing tank 5, so as to achieve the desolventizing of the PAG polymer and water in the PAG quenching liquid. According to this arrangement, the residual heat of the high-temperature forging S after tempering on the heat treatment production line can be fully and reasonably utilized, thereby improving the concentration and desolventizing efficiency of the PAG quenching liquid in the aqueous solution.

[0080] As some embodiments, during the evaporation and concentration stage, the high-temperature forging S can use its own 400-500°C to evaporate and concentrate the aqueous solution in the evaporation tank 1. When the temperature of the high-temperature forging S is reduced to 100-200°C, the high-temperature forging S can be directly lifted to the desolventizing tank 5 by the lifting device 21 for further heating, thereby rationally utilizing the high-temperature forging S that has been tempered on the production line to ensure orderly operation of the production line.

[0081] As some preferred embodiments, in step S2, after the high-temperature forging S evaporates water vapor for a certain period of time above the evaporation tank 1, it can be immersed in the evaporation tank 1 through the lifting device 21 to dissolve the PAG polymer attached to the high-temperature forging S back into the aqueous solution. This arrangement can avoid excessive accumulation of PAG polymer on the surface of the forging, thereby reducing the concentration of PAG quenching liquid in the evaporation tank 1.

[0082] By gradually adding heat treatment wastewater to the evaporation tank 1 during the evaporation concentration process, the heat treatment wastewater can be treated continuously, thereby achieving efficient recovery of high-concentration PAG quenching liquid.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for treating heat treatment wastewater containing PAG quenching liquid, characterized in that: The steps include: S1, passing the heat treatment wastewater generated by switching the quenching liquid into the evaporation tank (1); S2, lifting the tempered high-temperature forging (S) to the top of the evaporation tank (1), continuously spraying the heat treatment wastewater in the evaporation tank (1) onto the surface of the high-temperature forging (S), and repeatedly evaporating the water vapor in the heat treatment wastewater by using the high-temperature forging (S); S3, when the concentration of the PAG quenching liquid in the heat treatment wastewater in the evaporation tank (1) reaches a first predetermined value, the first predetermined value is the concentration ratio of the PAG quenching liquid in the heat treatment wastewater, and the first predetermined value is 2%-5%, the heat treatment wastewater containing the PAG quenching liquid is pumped into the desolventizing tank (5) for concentration; S4, using a high temperature forging (S) to repeatedly heat and evaporate the heat treatment wastewater in the desolventizing tank (5), and desolventize the PAG quenching liquid and water in the heat treatment wastewater; S5, when the concentration of the PAG quenching liquid in the heat treatment wastewater in the desolventizing tank (5) reaches a second predetermined value, the second predetermined value is the concentration ratio of the PAG quenching liquid in the heat treatment wastewater, and the second predetermined value is greater than 5%, the PAG quenching liquid at the bottom of the desolventizing tank (5) is recovered through the collecting tank (3) for reuse; The high temperature forging (S) first evaporates the water vapor of the heat treatment wastewater in the evaporation tank (1), and then uses the residual heat of the high temperature forging (S) to heat the heat treatment wastewater in the desolventizing tank (5) to desolventize the PAG quenching liquid and water in the heat treatment wastewater; In step S2, after the high-temperature forging (S) evaporates water vapor above the evaporation tank (1) for a certain period of time, it is immersed in the evaporation tank (1) through the lifting device (21) to dissolve the PAG quenching liquid attached to the high-temperature forging (S) back into the heat treatment wastewater; The method for treating heat treatment wastewater containing PAG quenching liquid uses a heat treatment wastewater treatment system containing PAG quenching liquid, and the heat treatment wastewater treatment system containing PAG quenching liquid includes: An evaporation tank (1) for containing heat-treated wastewater; The separation mechanism (2) comprises a lifting device (21) and a sprayer (22), wherein the lifting device (21) is used to lift the tempered high-temperature forging (S) to the top of the evaporation tank (1), and the sprayer (22) is used to repeatedly spray the heat treatment waste water in the evaporation tank (1) onto the surface of the high-temperature forging (S) to perform water vapor evaporation separation; A collecting tank (3) is connected to the evaporation tank (1) and is used to collect the concentrated PAG quenching liquid in the evaporation tank (1); and further includes a precipitation storage tank (4), the precipitation storage tank (4) is used to collect heat treatment wastewater, and the precipitation storage tank (4) is connected to the evaporation tank (1) via a flow control valve (41); It also includes a desolventizing tank (5), which is connected to the evaporating tank (1) and the collecting tank (3) respectively, and is used to heat the heat treatment wastewater transported to the desolventizing tank (5) to desolventize the PAG quenching liquid and water in the heat treatment wastewater; The separation mechanism (2) further comprises an evaporation chamber (23), wherein the evaporation chamber (23) is movably arranged directly above the evaporation tank (1), and an operating space is provided between the evaporation chamber (23) and the evaporation tank (1) for the lifting device (21) to enter; The separation mechanism (2) further comprises an exhaust device (24) installed on the evaporation chamber (23), wherein the exhaust device (24) is used to exhaust water vapor evaporated from the high-temperature forging (S) from the evaporation chamber (23).

2. The method for treating heat treatment wastewater containing PAG quenching liquid according to claim 1, characterized in that: A first concentration sensor is arranged inside the evaporation tank (1), and the first concentration sensor is used to detect the concentration of the PAG quenching liquid in the heat treatment wastewater in the evaporation tank (1).

3. The method for treating heat treatment wastewater containing PAG quenching liquid according to claim 2, characterized in that: A temperature sensor and a second concentration sensor are arranged inside the desolventizing tank (5), wherein the temperature sensor is used to detect the temperature of the heat treatment wastewater inside the desolventizing tank (5), and the second concentration sensor is used to detect the concentration of the PAG quenching liquid in the heat treatment wastewater inside the evaporation tank (1).

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