Lubricating oil recovery system

Abstract

The invention provides a lubricating oil recovery system, and relates to the field of lubricating oil recovery treatment. The lubricating oil recovery system comprises a pretreatment unit, a primary purification unit, an intermediate treatment unit and a deep refining unit, and the pretreatment unit, the primary purification unit, the intermediate treatment unit and the deep refining unit are sequentially connected; the pretreatment unit is used for preheating and screening lubricating oil and monitoring oil quality parameters; the primary purification unit comprises a centrifugal machine, a two-stage filtering module, an activated carbon adsorption tower and a three-way valve which are sequentially connected, a pipeline is connected between the activated carbon adsorption tower and the three-way valve, an online quality feedback module is arranged on the pipeline, and one end of the three-way valve is connected with a return pipe connected with the centrifugal machine; the intermediate treatment unit comprises a pickling reaction kettle, a carclazyte adsorption tower and a neutralizing tank which are connected in sequence; a lime powder inlet pipe is arranged at the top of the pickling reaction kettle. After heating detection of the pretreatment unit, the intermediate treatment unit and the deep refining unit integrate waste heat recovery, and efficient grading regeneration of waste oil is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating oil recovery and processing, in particular to a lubricating oil recovery system. Background Art

[0002] Lubricating oil is an essential component of modern machinery, primarily reducing friction, minimizing wear, and extending mechanical life. However, lubricating oil gradually loses its performance over time, not only failing to meet the requirements of the equipment but also potentially causing serious environmental pollution.

[0003] As the concept of sustainable development becomes increasingly popular, the waste oil recycling lubricant industry is gradually becoming a cutting-edge industry, becoming a focus of environmental protection and efficient resource utilization. Waste oil production has shown a year-on-year increase, providing a rich source of raw materials for the waste oil recycling lubricant base oil industry. For example, in Xinjiang, the production of HW08 waste mineral oil and mineral oil-containing waste reached 1.7376 million tons in 2024, accounting for nearly 30% of the region's total hazardous waste production, a significant increase from the previous year. This trend is also reflected in other regions of China. If such a large amount of waste oil can be properly recycled and efficiently utilized, it will undoubtedly provide broad development opportunities for the waste oil recycling lubricant base oil industry.

[0004] Current lubricant oil recovery systems have significant technical limitations: Traditional systems generally employ a single, standardized treatment model, applying the same process to lubricants of varying degrees of deterioration (mild, moderate, or severe). This one-size-fits-all approach forces even mildly deteriorated lubricants, such as those containing only small amounts of water and trace metal particles, to undergo advanced processing steps, including pickling and vacuum distillation. This lack of tiered processing capabilities not only wastes energy and increases processing costs, but also prolongs the processing cycle and compromises the efficiency of the regenerated oil. Therefore, the present invention provides a lubricant oil recovery system. Summary of the Invention

[0005] (1) Technical problems solved

[0006] In view of the deficiencies of the prior art, the present invention provides a lubricating oil recovery system, which solves the problems raised by the above-mentioned background technology.

[0007] (2) Technical solution

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: a lubricating oil recovery system, comprising a pretreatment unit, a primary purification unit, an intermediate treatment unit and a deep refining unit, wherein the pretreatment unit, the primary purification unit, the intermediate treatment unit and the deep refining unit are sequentially connected;

[0009] The pretreatment unit is used to preheat and screen the lubricating oil and monitor oil quality parameters;

[0010] The primary purification unit includes a centrifuge, a two-stage filtration module, an activated carbon adsorption tower and a three-way valve connected in sequence, a pipeline is connected between the activated carbon adsorption tower and the three-way valve, an online quality feedback module is provided on the pipeline, and one end of the three-way valve is connected to a reflux pipe connected to the centrifuge;

[0011] The intermediate treatment unit includes a pickling reactor, a clay adsorption tower and a neutralization tank connected in sequence, and a lime powder inlet pipe is provided on the top of the pickling reactor;

[0012] The deep refining unit comprises a distillation tower, a solvent extraction tower and a hydrogenation reactor which are connected in sequence, and a waste heat utilization unit is provided between the distillation tower and the pretreatment unit.

[0013] Preferably, the pretreatment unit includes a heater, a detection module and a vibration screening module connected in sequence.

[0014] Preferably, the waste heat utilization unit includes a heat exchanger connected to the heater and a delivery pipe connected to the distillation tower, and the delivery pipe is connected to the heat exchanger.

[0015] Preferably, the detection module includes a first vibration viscometer, a first dielectric constant sensor, a metal wear particle sensor, a pH sensor and a moisture sensor.

[0016] Preferably, the online quality feedback module includes a second vibration viscometer and a second dielectric constant sensor provided on the pipeline.

[0017] Preferably, the vibration screening module includes a multi-layer screen and a magnetic adsorption plate arranged at the bottom of the screen, the screen aperture decreases from top to bottom, and the magnetic adsorption plate is set to a conical structure and an electromagnet structure.

[0018] Preferably, the pickling reactor is provided with a pH value online control system, which includes an acid-base filling pump and a pH probe provided on the inner wall of the reactor, and the acid-base filling pump is connected to the pH probe signal through a PID controller.

[0019] Preferably, the hydrogenation reactor adopts a segmented temperature control structure, comprising:

[0020] The upper reaction zone is provided with a first catalyst layer and a first temperature control unit;

[0021] The lower reaction zone is provided with a second catalyst layer and a second temperature control unit;

[0022] The first temperature control unit and the second temperature control unit operate independently, and both adopt a composite temperature control structure of surround electric heating and circulating water cooling.

[0023] Preferably, the two-stage filtration module includes a ceramic filter element filter and a polyimide polymer membrane filter, and the deep refining unit also includes a molecular sieve adsorption layer connected to the hydrogenation reactor.

[0024] (3) Beneficial effects

[0025] The present invention provides a lubricating oil recovery system, which has the following beneficial effects:

[0026] 1. In the present invention, waste oil undergoes heating and testing in a pretreatment unit to determine its degree of deterioration (mild, moderate, or severe). After vibratory screening and impurity removal, it enters a primary purification unit where it undergoes centrifugation, precision filtration, and activated carbon adsorption. Unqualified oil is then returned for further processing. Moderately deteriorated oil undergoes acid washing and clay refining in a secondary treatment unit. Severely deteriorated oil undergoes vacuum distillation, solvent extraction, hydrorefining, and molecular sieve adsorption in a deep refining unit. The system integrates waste heat recovery to achieve efficient, graded regeneration of waste oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the system structure of the present invention;

[0028] Figure 2 Schematic diagram of the detection module structure of the present invention;

[0029] Figure 3 It is a structural schematic diagram of the vibration screening module of the present invention.

[0030] Among them, 1. Pretreatment unit; 11. Heater; 12. Detection module; 121. First vibration viscometer; 122. First dielectric constant sensor; 123. Metal abrasive sensor; 124. pH sensor; 125. Moisture sensor; 13. Vibration screening module; 131. Screen; 132. Magnetic adsorption plate; 2. Primary purification unit; 21. Centrifuge; 22. Ceramic filter element filter; 23. Polyimide polymer membrane filter; 24. Activated carbon adsorption tower; 25. Second vibration viscometer; 26. Second dielectric constant sensor; 27. Three-way valve; 28. Reflux pipe; 3. Intermediate treatment unit; 31. Pickling reactor; 32. Lime powder inlet pipe; 33. White clay adsorption tower; 34. Neutralization tank; 4. Deep refining unit; 41. Distillation tower; 42. Solvent extraction tower; 43. Hydrogenation reactor; 44. Molecular sieve adsorption layer; 5. Transport pipe; 6. Heat exchanger. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0032] Example:

[0033] like Figure 1-3 As shown, an embodiment of the present invention provides a lubricating oil recovery system, including a pretreatment unit 1, a primary purification unit 2, an intermediate treatment unit 3 and a deep refining unit 4. The pretreatment unit 1, the primary purification unit 2, the intermediate treatment unit 3 and the deep refining unit 4 are connected in sequence. The pretreatment unit 1 is used to preheat and screen the lubricating oil and monitor oil quality parameters. The pretreatment unit 1 includes a heater 11, a detection module 12 and a vibration screening module 13 connected in sequence. The detection module 12 includes a first vibration viscometer 121, a first dielectric constant sensor 122, a metal abrasive sensor 123, a pH sensor 124 and a moisture sensor 125.

[0034] A vibration viscometer is an instrument used to measure the viscosity of a liquid. It determines the viscosity by introducing vibrations into the liquid and measuring the liquid's response to the vibrations. A lubricating oil dielectric constant sensor is a device used to monitor the dielectric constant of lubricating oil in real time. The dielectric constant is a physical quantity that measures the ability of a material to store charge in an electric field. For lubricating oil, changes in its dielectric constant can reflect the health status, aging, and contamination of the oil. A moisture sensor is a measurement technology based on dielectric constant, which is mainly implemented through the principle of capacitance. The oil metal particle sensor (GTI-FCS400) uses the disturbance generated by ferromagnetic metal particles in the machine oil when they pass through the sensor's magnetic field area to be tested, causing the magnetic lines of force or magnetic flux related to the number of abrasive particles in the detection area to change, and calibrates the detection to detect the number of abrasive particles.

[0035] Preprocessing stage:

[0036] The waste oil is preheated by the heater 11 and then enters the detection module 12 after the viscosity is reduced. The real-time monitoring and display includes: kinematic viscosity, dielectric constant, Fe content, acidity value and water content.

[0037] Automatically determine the degree of oil deterioration based on NAS contamination levels and AI models:

[0038] Mild deterioration (NAS 6-8): moisture <3%, acid value <1.5mgKOH / g, metal particle concentration <100ppm;

[0039] Moderately deteriorated (NAS 9-11): Contains oily sludge / varnish, acid value 1.5-3.5 mgKOH / g, moisture 3-10%;

[0040] Severe deterioration (NAS grade 12 and above): oxidized polymer > 15%, acid value > 3.5mgKOH / g, moisture > 10%.

[0041] Mildly deteriorated lubricating oil is recycled after primary purification, moderately deteriorated lubricating oil is recycled after primary purification and intermediate treatment units, and severely deteriorated lubricating oil is recycled after primary purification, intermediate treatment and deep refining.

[0042] The vibration screening module 13 includes a multi-layer screen 131 and a magnetic adsorption plate 132 provided at the bottom of the screen 131. The aperture of the screen 131 decreases from top to bottom. The magnetic adsorption plate 132 is a conical structure and an electromagnet structure.

[0043] The vibrating screening module 13 performs graded filtration: the multi-layer stainless steel filter screen performs gradient filtration to remove debris, and the conical magnetic adsorption plate 132 at the bottom layer further captures ferromagnetic particles.

[0044] The primary purification unit 2 includes a centrifuge 21, a two-stage filtration module, an activated carbon adsorption tower 24 and a three-way valve 27 connected in sequence. A pipeline is connected between the activated carbon adsorption tower 24 and the three-way valve 27. An online quality feedback module is provided on the pipeline. The online quality feedback module includes a second vibration viscometer 25 and a second dielectric constant sensor 26 provided on the pipeline. One end of the three-way valve 27 is connected to a reflux pipe 28 connected to the centrifuge 21. The two-stage filtration module includes a ceramic filter element filter 22 and a polyimide polymer membrane filter 23.

[0045] Primary purification stage:

[0046] Centrifuge 21 separates free water and suspended solids, producing oil that enters a two-stage filtration module. Ceramic element filter 22 in the filtration module retains micron-sized particles, while polyimide polymer membrane filter 23 removes colloids. The filtered oil then flows through activated carbon adsorption tower 24 to remove colloid and oxide residues. A viscosity-dielectric sensor is deployed at the outlet. If a second vibration viscometer 25 and second dielectric constant sensor 26 detect viscosity fluctuations or a high dielectric constant, the oil is recirculated to centrifuge 21 for secondary treatment. Once the oil meets the required standards, it passes through three-way valve 27 and enters intermediate treatment unit 3.

[0047] The intermediate processing unit 3 includes a pickling reactor 31, a clay adsorption tower 33 and a neutralization tank 34 connected in sequence. A lime powder inlet pipe 32 is provided on the top of the pickling reactor 31. The pickling reactor 31 is provided with a pH value online control system. The pH value online control system includes an acid and alkali filling pump and a pH probe provided on the inner wall of the reactor. The acid and alkali filling pump is connected to the pH probe signal through a PID controller.

[0048] The white clay adsorption tower is a treatment equipment that uses white clay as an adsorbent. It is filled with a large number of white clay particles. When the oil entering the tower flows through the white clay particles, the pollutants will be adsorbed onto the surface of the white clay, thereby achieving the purpose of purification.

[0049] Intermediate processing stage:

[0050] Hydrochloric acid is injected into the pickling reactor 31. Feedback from the pH probe allows a PID controller to dynamically adjust the acid and alkali injection pumps to maintain the pH. Excess acid is neutralized through lime powder inlet pipe 32, which not only helps settle the acid residue but also further improves the quality of the regenerated lubricating oil. Subsequently, the acid residue is removed and supplemented with activated clay for refining. After passing through the clay adsorption tower 33, the pH is adjusted using sodium hydroxide solution in the neutralization tank 34.

[0051] The deep refining unit 4 includes a distillation tower 41, a solvent extraction tower 42, a hydrogenation reactor 43 and a molecular sieve adsorption layer 44 connected in sequence. A waste heat utilization unit is provided between the distillation tower 41 and the pretreatment unit 1. The waste heat utilization unit includes a heat exchanger 6 connected to the heater 11 and a conveying pipe 5 connected to the distillation tower 41, and the conveying pipe 5 is connected to the heat exchanger 6.

[0052] Deep refining stage:

[0053] The distillation tower 41 operates at a temperature of 200-300°C and a vacuum of <10 kPa to separate the base oil fraction. Asphaltene and colloidal substances 5 are removed via a solvent extraction tower 42 (propane to oil volume ratio 4:1). The hydrogenation reactor 43 performs hydrogen catalytic reduction of oxidized components, and finally a molecular sieve adsorption layer 44 (type 5A) performs deep decolorization.

[0054] The heat exchanger 6 recovers the waste heat from the distillation tower 41 and uses it to preheat the crude oil, thus achieving waste heat utilization and environmentally friendly treatment.

[0055] The hydrogenation reactor 43 adopts a segmented temperature control structure, including an upper reaction zone and a lower reaction zone. The upper reaction zone is provided with a first catalyst layer and a first temperature control unit, and the lower reaction zone is provided with a second catalyst layer and a second temperature control unit. The first temperature control unit and the second temperature control unit operate independently, and both adopt a surround-type electric heating and circulating water cooling composite temperature control structure.

[0056] The hydrogenation reactor 43 has segmented temperature control: the upper reaction zone is set at 300-350°C and filled with a W-Ni catalyst (WO3 loading 30%) to complete demetallization and preliminary hydrogenation; the lower reaction zone is set at 380-400°C and filled with a nickel-molybdenum catalyst (NiO loading 6%) to achieve deep desulfurization and aromatics saturation, and the reaction rate is synergistically controlled with a composite temperature control structure.

[0057] Working principle:

[0058] Waste oil first enters pretreatment unit 1. After being preheated by heater 11, multi-parameter sensors in detection module 12 monitor key indicators such as kinematic viscosity, dielectric constant, metal content, acid value, and water content in real time. Combining the NAS contamination level with an AI model, the oil's degree of deterioration (mild, moderate, or severe) is automatically determined. After the vibration screening module 13 removes solid impurities through gradient filtration and electromagnetic adsorption, the oil enters primary purification unit 2. Dehydration and impurity removal are achieved in a centrifuge 21, followed by two stages of precision filtration (ceramic filter element and polymer membrane), and purification in an activated carbon adsorption tower 24. An online quality feedback module monitors purification results in real time, and unqualified oil is returned through a three-way valve 27 for further processing. For moderately deteriorated oil, secondary treatment unit 3 uses an online pH control system in the pickling reactor 31 for precise acid treatment. Chemical refining is then completed in conjunction with a clay adsorption tower 33 and a neutralization tank 34. Severely deteriorated oil enters the deep refining unit 4, where it undergoes fraction separation in the vacuum distillation tower 41, deasphalting in the solvent extraction tower 42, catalytic reduction in the hydrogenation reactor 43, and deep refining in the molecular sieve adsorption layer 44, ultimately producing recycled base oil. The system utilizes a waste heat recovery unit to efficiently recycle waste oil of varying degrees of deterioration.

[0059] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A lubricating oil recovery system comprising a pre-treatment unit (1), a primary purification unit (2), an intermediate treatment unit (3) and a deep refining unit (4), characterized in that: The pretreatment unit (1), the primary purification unit (2), the intermediate treatment unit (3) and the deep refining unit (4) are sequentially connected; The pretreatment unit (1) is used for preheating and screening lubricating oil and monitoring oil quality parameters; The primary purification unit (2) comprises a centrifuge (21), a two-stage filtration module, an activated carbon adsorption tower (24) and a three-way valve (27) connected in sequence, a pipeline is connected between the activated carbon adsorption tower (24) and the three-way valve (27), an online quality feedback module is provided on the pipeline, and one end of the three-way valve (27) is connected to a reflux pipe (28) connected to the centrifuge (21); The intermediate treatment unit (3) comprises a pickling reactor (31), a clay adsorption tower (33) and a neutralization tank (34) connected in sequence, and a lime powder inlet pipe (32) is provided on the top of the pickling reactor (31); The deep refining unit (4) comprises a distillation tower (41), a solvent extraction tower (42) and a hydrogenation reactor (43) connected in sequence, and a waste heat utilization unit is provided between the distillation tower (41) and the pretreatment unit (1).

2. A lubricating oil recovery system according to claim 1, characterized in that: The pretreatment unit (1) comprises a heater (11), a detection module (12) and a vibration screening module (13) which are connected in sequence.

3. A lubricating oil recovery system according to claim 2, characterized in that: The waste heat utilization unit comprises a heat exchanger (6) connected to the heater (11) and a delivery pipe (5) connected to the distillation tower (41), wherein the delivery pipe (5) is connected to the heat exchanger (6).

4. The lubricating oil recovery system according to claim 2, characterized in that: The detection module (12) comprises a first vibration viscometer (121), a first dielectric constant sensor (122), a metal abrasive particle sensor (123), a pH sensor (124), and a moisture sensor (125).

5. The lubricating oil recovery system according to claim 1, characterized in that: The online quality feedback module comprises a second vibration viscometer (25) and a second dielectric constant sensor (26) arranged on the pipeline.

6. The lubricating oil recovery system according to claim 2, characterized in that: The vibration screening module (13) comprises a multi-layered screen (131) and a magnetic adsorption plate (132) arranged at the bottom of the screen (131). The aperture of the screen (131) decreases from top to bottom. The magnetic adsorption plate (132) is configured as a conical structure and an electromagnet structure.

7. The lubricating oil recovery system according to claim 6, characterized in that: The pickling reactor (31) is provided with a pH value online control system, which includes an acid-base injection pump and a pH probe provided on the inner wall of the reactor, and the acid-base injection pump is connected to the pH probe signal through a PID controller.

8. The lubricating oil recovery system according to claim 1, characterized in that: The hydrogenation reactor (43) adopts a segmented temperature control structure, including: The upper reaction zone is provided with a first catalyst layer and a first temperature control unit; The lower reaction zone is provided with a second catalyst layer and a second temperature control unit; The first temperature control unit and the second temperature control unit operate independently, and both adopt a composite temperature control structure of surround electric heating and circulating water cooling.

9. The lubricating oil recovery system according to claim 1, characterized in that: The two-stage filtration module includes a ceramic filter element filter (22) and a polyimide polymer membrane filter (23), and the deep refining unit (4) also includes a molecular sieve adsorption layer (44) connected to the hydrogenation reactor (43).

Images