Static degumming purification process for internal mixer sealing ring lubricating oil based on electrostatic coalescence technology

Abstract

The invention provides a cascade degumming and purifying process for internal mixer sealing ring lubricating oil based on an electrostatic coalescence technology, and belongs to the technical field of industrial lubricating oil deep purification, the cascade degumming and purifying process for the internal mixer sealing ring lubricating oil based on the electrostatic coalescence technology comprises the following steps: collecting internal mixer sealing ring waste lubricating oil, and carrying out coarse filtration; heating the oil subjected to coarse filtration by a heater, feeding the heated oil into a vacuum vaporizing chamber, and carrying out negative pressure distillation dehydration; the temperature of the heater and the vacuum degree of the vacuum vaporizing chamber are optimized, and the oxidative deterioration speed of oil liquid is reduced as much as possible while rapid distillation separation of water is achieved; centrifugally separating the dewatered oil by utilizing the difference between the density of impurities and the density of lubricating oil; residual dissolved rubber impurities in the lubricating oil after centrifugal separation are removed through an electrostatic coalescence technology; and the requirement of cyclic utilization can be met, the hazardous waste output of enterprises can be reduced, the purchase cost of the lubricating oil can be reduced, and the aims of saving energy and reducing consumption are achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of deep purification of industrial lubricating oil, and particularly relates to a step-by-step degumming and purification process for a mixer seal ring lubricating oil based on electrocoalescence technology. BACKGROUND

[0002] With the increasing downward pressure on the global economy, weak consumer demand, and increasingly fierce market competition, especially the traditional manufacturing industry is facing unprecedented survival pressure, so enterprises are not only increasing the competitiveness of products but also trying to find ways to reduce costs and increase efficiency in the production process.

[0003] In recent years, the purification and recycling of industrial lubricating oil have been rapidly promoted in enterprises where lubricating oil is widely used. However, the use of general vacuum oil filters, oil filter trolleys and other oil filtering equipment has great limitations, especially for the purification and filtration of tire industry mixer seal ring lubricating oil. Due to the particularity of the structure of the mixer equipment, a large amount of carbon black, small material and rubber will leak from the rotor mechanical seal ring during normal production, polluting the seal ring lubricating oil and causing the impurity content in the seal ring lubricating oil to be severely over-standard, which cannot meet the requirements of recycling and can only be disposed of as hazardous waste (HW-08) at a cost, increasing the environmental pressure on enterprises and production costs. Traditional filter cartridges are easily clogged, high-cost, low-efficiency, and the mixed rubber has a certain degree of compatibility with the lubricating oil, which is difficult to remove by filtration, and the residual rubber impurities can easily block the oil conveying pipeline, plunger pump, distributor and other equipment, affecting the normal operation of the equipment, so rubber tire enterprises urgently need a purification process and degumming method that can effectively separate and remove the gelatinous suspended matter and dissolved rubber formed after the lubricating oil is swelled and softened, to ensure that the purified lubricating oil meets the use requirements and does not block the plunger pump, distributor, pipeline and other lubricating oil conveying equipment, thereby reducing hazardous waste emissions and reducing the procurement cost of lubricating oil.

[0004] Research has found that the rubber mixed in the waste lubricating oil from the mixer seal ring can be divided into three forms, namely, sedimentation, suspension and dissolution. How to completely separate and remove the three forms of rubber contaminants is the key to the purification of the seal ring waste lubricating oil. The application solves the problems in the purification process of the mixer seal ring lubricating oil. SUMMARY

[0005] Therefore, the application provides a step-by-step degumming and purification process for a mixer seal ring lubricating oil based on electrocoalescence technology, which can meet the requirements of recycling, reduce the amount of hazardous waste generated by enterprises, reduce the procurement cost of lubricating oil, and achieve the goal of energy saving and consumption reduction.

[0006] The application is implemented as follows: The application provides a step-by-step degumming purification process for sealing ring lubricating oil of a banbury mixer based on electrostatic coalescence technology, and the specific steps include the following. S10: Collecting waste sealing ring lubricating oil of the banbury mixer and performing rough filtration; S20: After the rough filtration, the oil is heated by a heater and then enters a vacuum gasification chamber to perform negative pressure distillation and dehydration; S30: Optimizing the temperature of the heater and the vacuum degree of the vacuum gasification chamber to realize rapid distillation and separation of water and reduce the oxidation and deterioration speed of the oil as much as possible; S40: Using the density difference between impurities and lubricating oil to perform centrifugal separation on the dehydrated oil; S50: Through electrostatic coalescence technology, using the charge characteristics of rubber, carbon black and rubber additives, the charged colloidal impurities are made to flow directionally by electric field force to remove the residual dissolved rubber impurities in the lubricating oil after centrifugal separation; S60: Further filtering the oil after electrostatic coalescence separation by a fiber filter bag to filter and remove the suspended rubber micelles that have not completely settled after coalescence; S70: Detecting the lubricating oil after step-by-step degumming and purification.

[0007] The step-by-step degumming purification process for sealing ring lubricating oil of a banbury mixer based on electrostatic coalescence technology has the following technical effects: through rough filtration, large-particle impurities (such as rubber particles and deposited rubber) are removed to ensure that the subsequent process will not affect the normal operation of the equipment or block the pipeline due to the presence of these larger particles. After filtration, the remaining impurities in the oil have smaller particle sizes, reducing the burden in the subsequent steps.

[0008] Through heating and negative pressure distillation, the water in the lubricating oil is removed. The heater moderately heats the oil to promote the evaporation of water and extract it to the vacuum gasification chamber, thereby effectively removing the water and preventing it from remaining in the oil, ensuring the purity and performance of the oil.

[0009] By optimizing the temperature and vacuum degree, the water can be quickly evaporated, and the lubricating oil can be prevented from deteriorating due to high-temperature oxidation. By setting the oil temperature at 70-75 DEG C and the vacuum degree at -0.08 MPa, the efficiency of the distillation process is ensured, and the oxidation risk of the oil is reduced, protecting the original performance of the lubricating oil.

[0010] Through centrifugal separation, the density difference between the oil and impurities (such as rubber particles and carbon black) is used to separate most of the suspended impurities. Centrifugal separation not only improves the purification efficiency but also avoids the influence of impurities on the quality of the lubricating oil in the subsequent treatment process. The control of temperature and speed ensures the effectiveness and efficiency of the separation process.

[0011] The electrostatic coalescence technology makes the charged colloidal impurities (such as dissolved rubber, carbon black, etc.) in the lubricating oil flow directionally and coalesce into clusters through the action of electric field force, and then removes these fine impurities remaining in the lubricating oil. The electrostatic coalescence technology makes the impurities more easily separated by changing the charge distribution, thereby improving the cleanliness of the oil.

[0012] The oil after electrostatic coalescence is further filtered by the fiber filter bag to remove the micelles that have not completely settled during the coalescence process from the oil. In this way, there are almost no suspended micelle impurities in the oil, ensuring the purity of the lubricating oil and further improving the quality of the oil.

[0013] The lubricating oil after the step-by-step degumming purification is subjected to strict quality detection, including kinematic viscosity, moisture content, and mechanical impurities, etc. to ensure that the lubricating oil meets the use standard. This step can confirm the effectiveness of the purification process and ensure that the final product has excellent performance and stability.

[0014] On the basis of the above technical solutions, the step-by-step degumming purification process for the sealing ring lubricating oil of the internal mixer based on the electrostatic coalescence technology can be further improved as follows: Among them, the electrostatic coalescence electrode adopts an interdigital array electrode plate, and a collection plate is arranged between two adjacent electrode plates; the rubber, carbon black and rubber additives are adhered to the collection plate of the electrostatic coalescence electrode by the electric field force, and the colloids on the collection plate continuously coalesce to form micelles, which are separated and removed from the lubricating oil under the action of gravity.

[0015] The beneficial effects of the above improvement scheme are that the design of the interdigital array electrode plate and the collection plate makes the colloidal impurities more efficiently coalesce to form micelles and settle, thereby improving the efficiency and precision of the electrostatic coalescence process.

[0016] Further, the temperature of the material entering the electrostatic coalescence process is 70-80℃, and the electrostatic coalescence voltage is a direct current voltage, which reduces the influence of viscous force and avoids the oxidation of the lubricating oil.

[0017] The beneficial effects of the above improvement scheme are that controlling the temperature and voltage helps to reduce the viscous force of the oil, avoids the oxidation of the lubricating oil caused by high temperature, and ensures the best electrostatic coalescence effect, avoiding damage to the performance of the oil.

[0018] Further, the electric field strength condition for electrostatic coalescence is selected as 600-1000V / mm to ensure the best electrostatic coalescence effect.

[0019] The beneficial effects of the above improvement scheme are that this electric field strength condition ensures the efficiency of the electrostatic coalescence process, which can effectively separate the colloidal impurities in the lubricating oil and improve the final purification effect.

[0020] Further, the collection of internal mixer sealing ring waste lubricating oil is coarsely filtered, the selected screen mesh is 60-100 meshes, which is used for filtering large particle rubber impurities and deposited rubber, and preventing the process pipeline from being blocked.

[0021] The beneficial effects of the above improvement scheme are that: selecting appropriate filter screen mesh and heater heating load helps to prevent large particle impurities from blocking the pipeline, while avoiding excessive oxidation of the lubricating oil, thereby improving the stability and effect of the entire purification process.

[0022] Further, the oil after coarse filtration is heated by the heater and then enters the vacuum gasification chamber for negative pressure distillation dehydration process, and the surface heating load of the heater is ≤2.5 W / cm2, which is used to ensure that the lubricating oil will not be excessively oxidized and deteriorated due to local high temperature during the heating process.

[0023] Further, the heater temperature and the vacuum degree of the vacuum gasification chamber are optimized to realize rapid distillation separation of water and reduce the oxidation and deterioration speed of the oil as much as possible. According to the water vapor-liquid equilibrium curve, the oil temperature entering the vacuum gasification chamber is set to 70-75°C, and the vacuum degree of the gasification chamber is -0.08 MPa, so as to realize rapid distillation separation of water.

[0024] Further, by utilizing the difference in density between impurities and lubricating oil, the oil after dehydration is subjected to centrifugal separation process at a temperature of 50-60°C, which can ensure the centrifugal separation effect without causing excessive oxidation of the lubricating oil.

[0025] Further, the centrifuge speed during the centrifugal separation process is 15000 r / min, and the separation factor reaches 15580 R.C.F, which is used to separate and remove most of the suspended rubber particles and carbon black impurities mixed in the lubricating oil.

[0026] Further, the detection of the lubricating oil after the step-by-step degumming and purification includes 40°C kinematic viscosity detection, water content detection and mechanical impurity detection.

[0027] Compared with the prior art, the step-by-step degumming and purification process for internal mixer sealing ring lubricating oil based on electrostatic coalescence technology provided by the present application has the following beneficial effects: 1. The combination process technology method of coarse filtration, vacuum gasification dehydration, centrifugal separation, electrostatic coalescence and precision filtration realizes step-by-step separation and purification of rubber impurities in different forms such as deposition, suspension and dissolution, and can effectively restore the viscosity index of the lubricating oil; 2. The centrifugal separation technology effectively solves the separation problem of suspended rubber impurities in high-viscosity gear oil; 3. The electrostatic coalescence technology can realize the coalescence separation of the dissolved rubber impurities in the lubricating oil, completely solve the rubber residue problem in the sealing ring waste lubricating oil of the internal mixer, and eliminate the lubricating oil road blockage phenomenon; The application provides a stepwise degumming and purification process for sealing ring waste lubricating oil of an internal mixer based on electrostatic coalescence technology, which can realize stepwise separation and removal of rubber impurities in different forms such as deposition, suspension and dissolution in the sealing ring waste lubricating oil of the internal mixer, eliminate the rubber deposition and blockage problem in the sealing ring waste lubricating oil purification and recycling process, and realize deep purification and recycling of the sealing ring waste lubricating oil of the internal mixer, thereby helping rubber tire enterprises to save energy, reduce emissions and reduce costs and increase benefits. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is an operation flow chart of a stepwise degumming and purification process for sealing ring lubricating oil of an internal mixer based on electrostatic coalescence technology; Figure 2 It is a process schematic diagram of a stepwise degumming and purification process for sealing ring lubricating oil of an internal mixer based on electrostatic coalescence technology; Figure 3 It is a comparison chart of mechanical impurity content of oil after filtration by different precision filter screens; Figure 4 It is a comparison chart of viscosity of oil after filtration by different precision filter screens; Figure 5 It is a comparison chart of oil flow after filtration by different precision filter screens; Figure 6 It is a gas-liquid equilibrium curve of water; Figure 7 It is a comparison chart of dehydration efficiency of a heater at different temperatures; Figure 8 It is a comparison chart of viscosity of oil after centrifugation at different temperatures; Figure 9 It is a comparison chart of mechanical impurity content of oil after centrifugation at different temperatures; Figure 10 It is a side view structure diagram of an interdigital array electrode plate; Figure 11 It is a three-dimensional structure diagram of an interdigital array electrode plate; Figure 12 It is a comparison chart of viscosity of oil after electrostatic coalescence at different electric field strengths; Figure 13 It is a comparison chart of mechanical impurity content of oil after electrostatic coalescence at different electric field strengths; Figure 14 It is a comparison chart of viscosity at different purification stages; Figure 15 It is a comparison chart of water content at different purification stages; Figure 16 It is a comparison chart of mechanical impurity content at different purification stages. DETAILED DESCRIPTION

[0029] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application.

[0030] As Figures 1-2 shown is an embodiment of a step-by-step degreasing and purifying process of a mixer sealing ring lubricating oil based on an electrostatic coalescence technology provided by the present application. In the embodiment, the specific steps include: S10: removing sedimentary rubber impurities: collecting mixer sealing ring waste lubricating oil in a rubber tire factory, and coarsely filtering the collected barrel waste lubricating oil. The coarsely filtering process uses a 80-100 mesh metal screen, which mainly filters out sedimentary rubber, oil sludge and large particle impurities to prevent pipeline blockage; S20: heating: after the coarsely filtered oil is heated by a heater, it enters a vacuum gasification chamber to perform negative pressure distillation dehydration. The heater uses an electric heating method, and the surface heat load of the heating tube in contact with the material is ≤2.5 W / cm2. Since the viscosity of the lubricating oil is large, if the surface heat load is too large, the lubricating oil is prone to oxidation and coking. A temperature detection point and a flow switch are arranged at the outlet of the heater to control the start and stop of the heater to prevent safety problems caused by excessively high heating oil temperature and empty burning of the heater; S30: vacuum gasification dehydration: optimizing the temperature of the heater and the vacuum degree of the vacuum gasification chamber can reduce the oxidation and deterioration speed of the oil as much as possible while realizing the rapid distillation separation of water. As can be seen from the gas-liquid equilibrium curve of water, the higher the vacuum degree, the lower the boiling point of water, i.e. the gasification temperature. Under the condition of meeting the suction stroke of the vacuum oil pump, the vacuum degree of the gasification chamber is as high as possible, so that a larger operating temperature interval can be obtained, which not only improves the dehydration efficiency but also reduces the oxidation of the oil; S40: removing suspended rubber impurities: the main impurities in the sealing ring waste lubricating oil are rubber and carbon black mixed therein. The density of the tire rubber is 1.0-1.9 g / cm 3 , the density of the carbon black is 1.0-2.0 g / cm 3 , and the density of the lubricating oil is 0.85-0.89 g / cm 3 . The dehydrated oil is centrifuged by taking advantage of the different densities of the rubber, carbon black and other impurities and the lubricating oil. The centrifugal force improves the separation speed of the rubber, carbon black and other impurities and the lubricating oil. In particular, when the centrifuge speed reaches 15000 r / min, the separation factor can reach 15580 R.C.F. This process can effectively remove the suspended rubber impurities and micelles in the lubricating oil. S50: removing dissolved rubber impurities: after centrifugal separation, part of the dissolved rubber impurities still remains in the lubricating oil. According to the principle of similar dissolves similar, the rubber has a certain solubility in the lubricating oil. The part of the rubber as a solute, the lubricating oil as a solvent, the rubber is uniformly dissolved in the oil in the form of molecules. This part of the dissolved rubber is difficult to separate by filtration or centrifugation. The part of the impurities can be removed by electrostatic coagulation technology. The rubber, carbon black and rubber additives have their own charge characteristics. By applying electrostatic field force, the charged colloidal impurities flow along the direction of the electric field and continuously coagulate and agglomerate on the collection plate between the positive and negative plates, and finally form larger colloidal particles. Because the density of the colloidal particles is larger, when the colloidal particles grow to a certain state, they will fall off from the surface of the collection plate and gradually deposit at the bottom of the electrostatic coagulation separator under the action of gravity, thereby realizing the removal of the residual dissolved rubber impurities in the lubricating oil after centrifugal separation. S60: supplementary filtration: after electrostatic coagulation, the larger colloidal particles can overcome the viscous force of the lubricating oil to realize sedimentation separation, and the smaller colloidal particles can be carried away by the flowing lubricating oil. Therefore, it is necessary to intercept and remove the smaller colloidal particles. The oil after electrostatic coagulation is further filtered by a fiber filter bag to remove the suspended colloidal particles that have not completely settled after electrostatic coagulation. The filter bag has a filtering precision of 0.5 microns. S70: detecting the lubricating oil after the step-by-step degreasing purification.

[0031] In the above technical solution, the electrostatic coagulation electrode adopts an interdigital array electrode plate, and a collection plate is arranged between two adjacent electrode plates. The collection plate can be made of polyethylene, polypropylene, polytetrafluoroethylene, ceramic or other insulating materials. The charged impurities such as rubber, carbon black and rubber additives flow in a direction by the action of electric field force and adhere to the collection plate between the electrostatic coagulation electrode plates. The colloidal particles continuously coagulate and agglomerate on the collection plate to form colloidal particles, which fall off and settle under the action of gravity, thereby realizing the separation and removal of the residual dissolved colloidal particles in the lubricating oil.

[0032] Further, in the above technical solution, the temperature of the material entering the electrostatic coagulation process is 70-80℃, and the electrostatic coagulation voltage is a direct current voltage. At this temperature, the influence of the viscous force of the lubricating oil can be reduced (when the temperature is 40℃, the kinematic viscosity is 325.16 mm 2 / s, and when the temperature is 100℃, the kinematic viscosity is only 25.31 mm 2 / s, that is, the higher the temperature, the lower the viscosity of the lubricating oil, and the smaller the viscous force), and the oxidation of the lubricating oil is avoided.

[0033] Further, in the above technical solution, the electric field strength condition for electrostatic coagulation is 600-1000V / mm to ensure the best electrostatic coagulation effect.

[0034] Comparative experiments such as Figures 10-13 As shown, the effect of electric field strength on electrostatic coalescence was studied. Seven sets of electric field strengths (400V / mm, 500V / mm, 600V / mm, 700V / mm, 800V / mm, 900V / mm, and 1000V / mm) were selected as variable conditions for parallel experiments, namely Examples 1 to 7. The waste lubricating oil after centrifugation was subjected to static electrostatic coalescence treatment within the same time period. The separation effect of electrostatic coalescence on dissolved rubber was characterized by detecting the viscosity and mechanical impurity index of the treated waste lubricating oil. The experimental results are shown in Table 1. Table 1. Effect of different electric field strengths on electrostatic coalescence.

[0035] The experimental results show that with the increase of electric field strength, the viscosity and mechanical impurities of waste lubricating oil decrease significantly. When the electric field strength reaches a certain level, the decrease is no longer significant. Moreover, when the field strength is too high, the viscosity and mechanical impurities tend to increase. The reason may be that the field strength is too high, causing excessive disturbance to the oil, which affects the coalescence and agglomeration process of rubber. Therefore, the electric field strength condition for electrostatic coalescence is selected as 600V / mm-1000V / mm to ensure the best electrostatic coalescence effect.

[0036] A certain amount of viscous substance can be discharged from the bottom of the electrostatic coalescence separation equipment. Testing showed that the kinematic viscosity of this viscous substance at 40°C is generally around 1000 mmHg. 2 The viscosity is above 1000 m / s, and when the temperature drops to room temperature of 20°C, the viscous substance becomes semi-solid, which indicates that it is mainly a sediment of aggregated and separated impurities such as rubber.

[0037] Furthermore, in the above technical solution, the waste lubricating oil of the internal mixer sealing ring is collected and coarsely filtered using a stainless steel wire mesh with a filter precision of 60-100 mesh. This is used to filter large rubber particles and deposited rubber to prevent clogging of process pipelines. If the filter mesh pore size is too large, larger particles will not be intercepted, resulting in poor coarse filtration. If the filter mesh pore size is too small, the filtration efficiency will be affected.

[0038] Comparative experiments such as Figures 3-5 As shown, in order to determine the optimal coarse filtration accuracy, metal wire meshes with the same filtration area were selected, and the filtration accuracy was a variable condition. In the experiment, parallel comparative coarse filtration experiments were conducted using filter meshes with the same filtration area of ​​40 mesh, 60 mesh, 80 mesh, 100 mesh, 120 mesh, 150 mesh and 180 mesh, respectively, which are Example 1 to Example 7. The mechanical impurity content and kinematic viscosity at 40℃ were used to characterize the coarse filtration degumming effect, and the flow rate was used to characterize the filtration efficiency. The experimental results are shown in Table 2 below. Table 2 Comparison of the effects of different precision filter screens on coarse filtration

[0039] As can be seen from the experimental results, with the increase of the filtering precision of the filter screen, the content of mechanical impurities and the kinematic viscosity decrease. When the filtering precision reaches a certain value, with the continuous increase of the filtering precision, the decrease of the mechanical impurities and the kinematic viscosity is no longer obvious, which indicates that at this time, the main factors affecting the viscosity and mechanical impurities of the lubricating oil are the micron-sized rubber micelles in the suspended state and the dissolved rubber. However, with the increase of the filtering precision, the filtering flow rate shows a downward trend, and especially when the precision exceeds 100 meshes, the flow rate decreases obviously, and the filtering efficiency is greatly affected.

[0040] Further, in the above technical solution, the oil material after coarse filtration is heated by the heater and then enters the vacuum gasification chamber, and the surface heating load of the heater is ≤2.5 W / cm2 during the negative pressure distillation dehydration process, which is used to ensure that the lubricating oil will not be excessively oxidized and deteriorated due to local high temperature during the heating process.

[0041] Further, in the above technical solution, the heater temperature and the vacuum degree of the vacuum gasification chamber are optimized to realize the rapid distillation separation of water and as far as possible to reduce the oxidation and deterioration speed of the oil. According to the water vapor-liquid equilibrium curve, the circulating dehydration experiment is adopted to determine that the oil material temperature entering the vacuum gasification chamber is set to 70-75℃, and the vacuum degree of the gasification chamber is-0.08 Mpa, so as to realize the rapid distillation separation of water. If the temperature is too high, it will accelerate the oxidation and deterioration process of the oil, and especially when the temperature exceeds 80℃, the oxidation speed of the lubricating oil will show exponential growth. If the temperature is too low, it will affect the gasification dehydration efficiency.

[0042] As shown in the comparative experiment, Figures 6-7 In order to determine the optimal dehydration temperature, the vacuum degree of the vacuum gasification chamber is unchanged, and the material temperature is a variable condition. The water content in the oil after dehydration is required to be ≤300PPm to ensure that the voltage is stable during the electrostatic coalescence process and no breakdown discharge phenomenon occurs. Due to the high water content of the waste lubricating oil, the circulating dehydration experiment is adopted during the experiment, and when the water content is ≤0.03%, it is considered that the dehydration is completed. Six groups of experiments, i.e. Example 1-Example 6, are selected for parallel experiment comparison, and the experimental vacuum degree is-0.08 Mpa. The dehydration time is used to represent the dehydration rate under different temperatures, as shown in Table 3 below. Table 3 Water removal efficiency under different temperatures

[0043] Experiments show that higher temperatures result in higher dehydration efficiency, but once a certain temperature is reached, the improvement in dehydration efficiency with increasing temperature is minimal. Considering the impact of temperature on lubricating oil oxidation, the dehydration temperature should be controlled within a reasonable range to ensure both dehydration efficiency and prevent lubricating oil oxidation.

[0044] Furthermore, in the above technical solution, the difference in density between impurities and lubricating oil is utilized (where the density of tire rubber is 1.0-1.9 g / cm³). 3 The density of carbon black is 1.0-2.0 g / cm³. 3 The density of lubricating oil is 0.85-0.89 g / cm³. 3 During the centrifugal separation process of dehydrated oil, viscosity can hinder the centrifugal separation and affect the separation effect. Therefore, the material needs to be at a certain temperature to reduce viscosity. The temperature should be selected between 50℃ and 60℃ to ensure the centrifugal separation effect without causing excessive oxidation of the lubricating oil.

[0045] Comparative experiments such as Figures 8-9 As shown, six temperature conditions (20℃, 30℃, 40℃, 50℃, 60℃, and 70℃) were selected for parallel comparative centrifugal separation experiments, namely Example 1 to Example 6. The separation effect of centrifugal separation on suspended rubber was characterized by detecting the viscosity and mechanical impurities of the separated lubricating oil. The experimental results are shown in Table 4. Table 4 Comparison of degumming effects of centrifugation at different temperatures

[0046] Experiments show that the higher the operating temperature and the lower the viscosity of the lubricating oil, the lower the viscosity of the separated oil and the lower the content of mechanical impurities, which means the separation and degumming effect is better. However, when a certain temperature is reached, the separation effect does not improve significantly with further increases in temperature, meaning that the effect of viscosity on the separation effect is no longer significant. Therefore, the centrifugal separation operating temperature should be selected at 50℃-60℃ to ensure the centrifugal separation effect without causing excessive oxidation of the lubricating oil.

[0047] Furthermore, in the above technical solution, the centrifuge speed in the centrifugal separation process is 15000 r / min, and the separation factor reaches 15580R.CF, which is used to separate and remove most of the suspended rubber particles and carbon black impurities mixed in the lubricating oil.

[0048] Furthermore, in the above technical solution, the lubricating oil after staged degumming and purification is tested, including kinematic viscosity at 40℃, moisture content, and mechanical impurities. The test indicators are shown in Table 5. Table 5: Test Indicators of Lubricating Oil After Staged Degumming and Purification

[0049] From the above table, the viscosity of the lubricating oil after step-by-step degreasing has basically recovered to the viscosity index of new oil, indicating that there is little rubber residue in the lubricating oil after step-by-step degreasing.

[0050] After the four-stage degreasing process of coarse filtration, centrifugal separation, electrostatic coalescence and precision filtration, the separation and removal of four different forms of rubber pollutants in the lubricating oil, i.e. large particle rubber block, sedimentary rubber, suspended rubber particles and dissolved rubber impurities, are finally realized, the viscosity index of the lubricating oil is restored, and the lubricating oil conveying and distribution system such as plunger pump, distributor and pipeline is ensured not to be blocked by rubber deposits, the good lubrication state of the sealing ring is maintained, the goal of resource recycling is achieved, not only the amount of lubricating oil procurement is reduced, but also the energy saving and emission reduction benefits are significant.

[0051] The detection method of mechanical impurities in the experimental detection index adopts the difference method detection (GB / T511), that is, a certain amount of oil m0 is filtered by qualitative filter paper, the filter paper is dried after filtration, and the weight difference△m before and after filtration of the filter paper is measured, which is the total amount of mechanical impurities in the filtered oil. The ratio of the difference value to the filtered oil sample is the content of mechanical impurities, and the formula is shown in formula one; Mechanical impurities=(△m / m0)×100%; The detection method of 40℃ kinematic viscosity in the experimental detection index adopts the countercurrent method detection (GB / T11137), the time t of oil flowing through the capillary viscometer is measured, and the product of time t and the corresponding coefficient k of the viscometer is the kinematic viscosity of the oil at 40℃. The formula is shown in formula two; 40℃ kinematic viscosity=t×k; The detection method of water content in the experimental detection index adopts the distillation method detection (GB / T260), a certain amount of oil sample m0 is weighed, the oil sample is distilled, and the distilled water is collected in the water separator. The volume of the collected water is vwater, the density of water is pwater, and the ratio of the weight of water to the weight of oil sample is the water content of the oil sample, and the formula is shown in formula three; Water content=((vwater×pwater) / m0)×100%.

[0052] Specifically, the principle of the present application is: collecting the sealing ring waste lubricating oil of the internal mixer, performing rough filtration; the oil after rough filtration is heated by a heater and then enters a vacuum air chamber to perform negative pressure distillation dehydration; the heater temperature and the vacuum degree of the vacuum air chamber are optimized, so that the rapid distillation separation of water is realized, and the oxidation and deterioration speed of the oil is reduced as much as possible; the oil after dehydration is centrifuged by using the difference in density between impurities and lubricating oil; through electrostatic coagulation technology, the charge characteristics of rubber, carbon black and rubber additives are used, the charged colloidal impurities are made to flow directionally by electric field force, and the dissolved rubber impurities remaining in the lubricating oil after centrifugal separation are removed; the oil after electrostatic coagulation separation is further filtered by a fiber filter bag, and the suspended colloidal particles after coagulation and not completely settled are filtered and removed; the lubricating oil after the step-by-step degumming purification is detected.

[0053] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which shall be covered within the protection scope of the present application.

Claims

1. A step-by-step degumming and purification process for lubricating oil in the sealing rings of a mixer based on electrostatic coalescence technology, characterized in that, The specific steps include: S10: Collect waste lubricating oil from the sealing ring of the internal mixer and perform coarse filtration; S20: After coarse filtration, the oil is heated by a heater and then enters a vacuum vaporization chamber for negative pressure distillation and dehydration; S30: Optimizes heater temperature and vacuum level in vacuum chamber to achieve rapid distillation and separation of water while minimizing the rate of oil oxidation and deterioration. S40: Utilizing the difference in density between impurities and lubricating oil, the dehydrated oil is separated by centrifugation; S50: Through electrostatic coalescence technology, the charge characteristics of rubber, carbon black and rubber additives are utilized to cause charged colloidal impurities to flow in a directional manner through electric field force, thereby removing dissolved rubber impurities remaining in the lubricating oil after centrifugal separation. S60: The oil after electrostatic coalescence separation is further filtered through fiber filter bags to remove suspended colloids that have not completely settled after coalescence; S70: Testing of lubricating oil after cascade degumming and purification.

2. The step-by-step degumming and purification process for internal mixer sealing ring lubricating oil based on electrostatic coalescence technology according to claim 1, characterized in that, The electrostatic coalescence electrode uses an interdigitated array of electrode plates, with a collection plate between two adjacent electrode plates; Rubber, carbon black, and rubber additives are adhered to the collection plate of the electrostatic coalescence electrode by electric field force. As the colloids on the collection plate continuously coalesce to form colloids, they fall off and settle under the action of gravity, thereby achieving the separation and removal of residual dissolved colloids in the lubricating oil.

3. The step-by-step degumming and purification process for internal mixer sealing ring lubricating oil based on electrostatic coalescence technology according to claim 2, characterized in that, The material temperature entering the electrostatic coalescence process is 70℃-80℃, and the electrostatic coalescence voltage is DC voltage, which reduces the influence of viscosity and avoids the oxidation of lubricating oil.

4. The step-by-step degumming and purification process for internal mixer sealing ring lubricating oil based on electrostatic coalescence technology according to claim 3, characterized in that, The electric field strength for electrostatic coalescence is selected to be 600V / mm-1000V / mm to ensure the best electrostatic coalescence effect.

5. The step-by-step degumming and purification process for internal mixer sealing ring lubricating oil based on electrostatic coalescence technology according to claim 4, characterized in that, The waste lubricating oil collected from the internal mixer sealing ring is coarsely filtered using a 60-100 mesh screen to filter out large particles of rubber impurities and deposited rubber, preventing blockage of process pipelines.

6. The step-by-step degumming and purification process for internal mixer sealing ring lubricating oil based on electrostatic coalescence technology according to claim 5, characterized in that, The oil, after being coarsely filtered, is heated by a heater and then enters a vacuum vaporization chamber for negative pressure distillation and dehydration. During this process, the heating load on the surface of the heater is ≤2.5W / cm2 to ensure that the lubricating oil does not undergo excessive oxidation and deterioration due to local high temperatures.

7. The step-by-step degumming and purification process for internal mixer sealing ring lubricating oil based on electrostatic coalescence technology according to claim 6, characterized in that, To achieve rapid distillation and separation of water while minimizing the rate of oil oxidation and deterioration, the heater temperature and vacuum degree of the vaporization chamber were optimized. Based on the gas-liquid equilibrium curve of water, a circulating dehydration experiment was conducted to determine that the oil temperature entering the vaporization chamber should be set at 70℃-75℃ and the vacuum degree of the vaporization chamber should be -0.08Mpa, so as to achieve rapid distillation and separation of water.

8. The step-by-step degumming and purification process for internal mixer sealing ring lubricating oil based on electrostatic coalescence technology according to claim 7, characterized in that, By taking advantage of the difference in density between impurities and lubricating oil, the temperature is selected at 50℃-60℃ during the centrifugal separation process of the dehydrated oil. This ensures the centrifugal separation effect without causing excessive oxidation of the lubricating oil.

9. The step-by-step degumming and purification process for internal mixer sealing ring lubricating oil based on electrostatic coalescence technology according to claim 8, characterized in that, The centrifuge speed during the centrifugation process is 15000 r / min, and the separation factor reaches 15580R.CF. It is used to separate and remove most of the suspended rubber particles and carbon black impurities mixed in the lubricating oil.

10. The step-by-step degumming and purification process for internal mixer sealing ring lubricating oil based on electrostatic coalescence technology according to claim 9, characterized in that, The testing of the lubricating oil after cascade degumming and purification includes kinematic viscosity testing at 40°C, moisture testing, and mechanical impurity testing.

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