Waste oil distillation regeneration system based on internal heating and internal circulation

Abstract

The utility model discloses a kind of waste oil distillation regeneration systems based on internal heating and internal circulation, belong to waste oil regeneration processing technical field.The system includes distiller, vacuum system, condensing collection system, electromagnetic heating device and double stirring device.Electromagnetic heating device is directly heated distiller tank body by inductive heating, and heat efficiency reaches 90%-98%;Double stirring device is formed by outer low-speed stirrer and inner high-speed stirrer, forms forced internal circulation flow field, strengthens heat transfer, prevents coking, ensures raw oil temperature uniform, and overall temperature gradient is controlled within ±0.5 ℃.Through vacuum decompression, electromagnetic heating and internal circulation collaborative operation, realize efficient distillation, significantly improve base oil yield, reduce energy consumption and operating cost.System structure simplification, cancel traditional boiler and external pipeline, stability and safety greatly improve, equipment occupies small, maintenance cost is low, and it has environmental protection and economic benefit.

Description

Technical Field

[0001] This utility model relates to the field of waste oil regeneration technology, and to a waste oil distillation regeneration system based on internal heating and internal circulation. Background Technology

[0002] With rapid industrialization, the production of waste mineral oils (such as waste engine oil and waste lubricating oil) has been increasing year by year. If these waste oils are discharged indiscriminately without treatment, they will cause serious environmental pollution. At the same time, waste oils contain a large amount of valuable base oil components. Through appropriate technical means, regeneration can not only turn waste into treasure and achieve resource recycling, but also bring considerable economic benefits. Vacuum distillation is currently the most core and widely used technology in the field of waste oil regeneration. Its principle is to lower the boiling point of the oil under negative pressure, thereby separating components with different boiling ranges at a lower temperature to extract high-value-added base oils, while avoiding cracking and coking of the oil at high temperatures.

[0003] In existing vacuum distillation processes, the heating method of the feed oil inside the still is a crucial factor determining the efficiency, stability, cost, and safety of the entire system. Currently, the mainstream heating technology is external heating, with thermal oil boiler heating being the most representative. This method uses a coal-fired, gas-fired, or oil-fired boiler to heat dedicated thermal oil to a high temperature, and then a circulating pump transports the high-temperature thermal oil to the jacket outside the still or the built-in heat exchange coils, indirectly transferring heat to the feed oil through heat conduction. However, this traditional external heating method has revealed a series of insurmountable technical defects in long-term practice, severely restricting the efficiency and economy of waste oil regeneration.

[0004] First, energy utilization efficiency is low and operating costs are high. Traditional boilers have an inherent upper limit to their combustion thermal efficiency; coal-fired boilers typically achieve 60%-80%, and gas-fired boilers only 80%-90%. More importantly, the heat transfer chain is excessively long, leading to multiple energy losses. Heat transfer from fuel combustion involves the following steps: 1) chemical energy is converted into thermal energy, accompanied by losses such as light energy; 2) heat is transferred to the air and chambers within the boiler; 3) the chambers heat the heat transfer oil; 4) the high-temperature heat transfer oil is transported through long external pipelines; 5) heat exchange occurs through the jacket or coils of the distiller. In this long chain, heat loss from boiler flue gas, heat loss from pipelines to the environment (which cannot be avoided even with insulation), and heat transfer temperature difference losses during multiple heat exchange processes all contribute to a significant reduction in the effective energy used to heat the feedstock oil, resulting in often lower overall energy utilization efficiency. This directly translates into high fuel costs and carbon emissions.

[0005] Secondly, the system response is sluggish, and temperature control accuracy is poor. Thermal oil boiler systems have significant thermal inertia; from startup to reaching the set operating temperature, gas-fired boilers require 15-30 minutes, while coal-fired boilers take as long as 30-120 minutes. This lengthy preheating and standby time not only wastes energy but also greatly reduces production flexibility. During the process, due to the lag in heat transfer, it is difficult to achieve rapid and precise adjustment of distillation temperature, which is detrimental to the fine-grained control of product fraction quality.

[0006] Third, the system structure is complex, and its stability and safety are poor. The external heating system relies on a complete set of external circulation equipment, including a boiler, a high-temperature oil pump, complex pipelines, valves, filters, etc. Failure in any component, such as a damaged oil pump, pipeline leak, or valve malfunction, will cause the entire production line to shut down. More seriously, the raw oil's fluidity decreases at high temperatures, making it highly susceptible to coking and blockage in external pipelines or heat exchangers with low heat exchange efficiency, making cleaning and maintenance extremely difficult. Furthermore, the high-temperature heat transfer oil itself poses a flammable and explosive risk; leaks can easily lead to fires and other safety accidents.

[0007] Fourth, distillation efficiency and base oil yield are limited. Traditional heating methods rely on passive heat conduction through the vessel walls, while feedstock oils (especially residue oil from later stages of processing) are typically high-viscosity fluids with poor thermal conductivity. Without efficient forced agitation, the oil adhering closely to the heat exchanger walls will form an overheated stagnant layer, prone to coking, while the oil in the central region far from the walls will be too cold to evaporate effectively. This results in extremely uneven temperature distribution within the vessel, low overall heat transfer efficiency, prolonged distillation time, and reduced base oil extraction rate.

[0008] Therefore, how to overcome the technical difficulties of high energy consumption, slow response, system instability and low distillation efficiency caused by traditional external heating methods, and develop a new type of waste oil distillation heating technology that is efficient, energy-saving, safe and stable, is an urgent technical problem to be solved in this field. Utility Model Content

[0009] In view of this, the purpose of this utility model is to solve the above problems and propose a waste oil distillation and regeneration system based on internal heating and internal circulation.

[0010] To achieve the above objectives, this utility model provides the following technical solution:

[0011] A waste oil distillation regeneration system based on internal heating and internal circulation includes a distiller, a vacuum system, and a condensation collection system. The system also includes:

[0012] An electromagnetic heating device is installed on the outer wall of the distiller tank, and is used to directly heat the distiller tank by induction heating.

[0013] A dual stirring device is installed inside the still, comprising an outer stirring unit and an inner stirring unit coaxially arranged. The outer stirring unit acts on the region adjacent to the inner wall of the still, while the inner stirring unit acts on the central region of the still. The outer and inner stirring units are configured to work synergistically to drive the feed oil to form a forced internal circulation flow field within the still, transporting the feed oil from the central region to the inner wall of the tank heated by the electromagnetic heating device for heat exchange.

[0014] Furthermore, the outer agitator is an anchor agitator or a frame agitator.

[0015] Furthermore, the outer agitator blades are equipped with scrapers for scraping the inner wall of the distiller to prevent material from coking and to enhance boundary layer heat transfer.

[0016] Furthermore, the inner agitator is a blade agitator, a propeller agitator, or a turbine agitator, used to generate the main body axial flow or radial flow.

[0017] Furthermore, the design speed of the outer agitator is lower than that of the inner agitator.

[0018] Furthermore, the outer agitator has a rotational speed range of 30–500 rpm, and the inner agitator has a rotational speed range of 200–3000 rpm.

[0019] The beneficial effects of this utility model are as follows:

[0020] Compared with the prior art, the present invention has the following significant advantages:

[0021] 1. Extremely high energy efficiency: Utilizing electromagnetic induction heating, electrical energy is directly converted into heat energy acting on the distiller tank itself. The heat transfer chain is shortened to only one step (from the tank wall to the oil), achieving a thermal efficiency of 90%-98%. This eliminates significant heat losses from boiler combustion, flue gas emissions, and long-distance pipeline transportation, resulting in significant overall energy savings and a substantial reduction in operating costs.

[0022] 2. Rapid Response and Precise Temperature Control: Electromagnetic heating has no thermal inertia, enabling instantaneous start and stop, flexible power adjustment, and extremely fast response. Combined with efficient internal circulation, it allows for rapid and precise control of feedstock oil temperature, which is beneficial for optimizing process parameters and improving product quality and yield.

[0023] 3. Simplified System, Significantly Improved Stability and Safety: The system eliminates a complex and vulnerable set of external equipment, including boilers, high-temperature oil pumps, and external circulation pipelines, greatly simplifying the system structure. Heating and circulation are both completed inside the distiller, shielding it from external environmental interference and fundamentally eliminating safety hazards caused by external pipeline blockages, leaks, and high-temperature heat transfer oil. This significantly reduces equipment failure rates and ensures extremely stable and reliable operation.

[0024] 4. Significantly Improved Distillation Efficiency and Yield: Electromagnetic heating provides the heat source, while the dual stirring device constructs a highly efficient "internal circulation heat exchange system." The outer scraper-type stirrer breaks up the stagnant layer on the wall, preventing coking and enhancing boundary heat transfer; the inner high-speed stirrer ensures rapid macroscopic mixing and temperature uniformity throughout the tank. The synergistic effect of these two components results in a heat transfer efficiency far exceeding that of traditional passive heat conduction, significantly shortening distillation time, ensuring uniform heating of the feedstock oil, and thus effectively improving the extraction rate of the base oil.

[0025] 5. Small footprint and low maintenance cost: Due to the simplified system structure, a large number of peripheral devices are reduced, effectively saving space. At the same time, the maintenance workload is simplified from maintaining the entire external circulation system to maintaining the stirring and electromagnetic heating devices, reducing maintenance costs and difficulty.

[0026] Other advantages, objectives, and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination and study, or may be learned from practice of this invention. The objectives and other advantages of this invention can be realized and obtained through the following description. Attached Figure Description

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings, wherein:

[0028] Figure 1 This is a schematic diagram of the waste oil distillation and regeneration system based on internal heating and internal circulation according to this utility model.

[0029] Figure 2 This is a schematic diagram of the dual stirring device in this utility model.

[0030] Reference numerals: 1-Distiller; 2-Cooler; 3-Spray tank; 4-Intermediate converter; 5-Vacuum converter; 6-Vacuum unit; 7-Tail gas collector; 8-Base oil collector; 9-Mixer; 10-Induced draft fan; 11-Scrubber tank; 12-Tail gas preheater; 13-T0 furnace; 101-Outer agitator; 102-Inner agitator. Detailed Implementation

[0031] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this utility model. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0032] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the present invention. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0033] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0034] Example 1

[0035] like Figure 1 As shown in the figure, this embodiment provides a waste oil distillation and regeneration system based on internal heating and internal circulation. Its core process mainly includes a distiller 1, an electromagnetic heating device, a dual stirring device, a cooler 2, an intermediate converter 4, and a base oil collector 8. The auxiliary parts of the system mainly include a vacuum system for maintaining a negative pressure environment and a tail gas treatment system for treating non-condensable gases.

[0036] An electromagnetic heating device (not shown separately) is installed on the outer wall of the distiller tank for directly heating the distiller tank by induction heating.

[0037] like Figure 2As shown, a dual stirring device is installed inside the still 1. The dual stirring device includes an outer stirring unit 101 and an inner stirring unit 102 arranged coaxially. The outer stirring unit 101 acts on the area adjacent to the inner wall of the still, while the inner stirring unit 102 acts on the central area of ​​the still. The outer stirring unit 101 and the inner stirring unit 102 are configured to work together to drive the feed oil to form a forced internal circulation flow field within the still 1, and transport the feed oil in the central area to the inner wall of the tank heated by the electromagnetic heating device for heat exchange.

[0038] The outer agitator 101 can be an anchor agitator or a frame agitator. The blades of the outer agitator 101 are equipped with scrapers to scrape the inner wall of the still, preventing material coking and enhancing boundary layer heat transfer. The inner agitator 102 can be an inclined blade agitator, a propeller agitator, or a turbine agitator, used to generate axial or radial flow in the main body. The rotational speed range of the outer agitator 101 is 30–500 rpm, and the rotational speed range of the inner agitator 102 is 200–3000 rpm.

[0039] The vacuum system mainly consists of a vacuum converter 5 and a vacuum unit 6.

[0040] The exhaust gas treatment system is a more complete treatment chain, mainly including exhaust gas collector 7, mixer 9, induced draft fan 10, scrubbing tank 11, spray tank 3, exhaust gas preheater 12, and T0 furnace 13 for final incineration treatment.

[0041] The following details a complete workflow of the system:

[0042] 1. System Startup and Preparation Phase

[0043] Before starting the feeding process, system preparation is performed. T0 furnace 13 is started for preheating. The cooling water inlet valve of cooler 2 is opened, and the cooling water pump is started to ensure smooth circulation of cooling water within cooler 2.

[0044] Subsequently, vacuum unit 6 is started to evacuate the entire process system. The airflow path is: distiller 1 → cooler 2 → intermediate converter 4 → vacuum converter 5 → vacuum unit 6. Vacuum converter 5 plays a role in buffering and stabilizing the vacuum level during this process. Once the preset process vacuum level (e.g., -0.095 MPa) is reached within the system, this state is maintained.

[0045] At the same time, the exhaust gas treatment system is activated to prepare for the treatment of continuously generated exhaust gases.

[0046] 2. Feeding and Core Distillation Stage

[0047] The pretreated feed oil is pumped into distiller 1 via a feed pump (not shown). Feeding is stopped when the liquid level reaches the set height.

[0048] At this point, the core distillation operation begins: the electromagnetic heating device installed on the outer wall of distiller 1 and the dual stirring device installed inside the distiller are activated simultaneously.

[0049] The electromagnetic heating device uses a high-frequency alternating magnetic field to rapidly induce heat in the metal tank of the distiller 1. The heat is transferred from the tank wall to the raw oil, achieving efficient "internal heating".

[0050] Meanwhile, the dual agitation devices inside distiller 1 operate at high speed. The outer, low-speed anchor or frame agitator scrapes against the tank wall, while the inner, high-speed inclined blade or propeller agitator drives the central oil to form a strong axial circulation. Working together, these two elements create a highly efficient forced "internal circulation" flow field within the tank, ensuring the feed oil is heated uniformly and rapidly, and effectively preventing coking on the tank walls. As the temperature continues to rise to the set value (e.g., 390°C), a large amount of the base oil components in the feed oil vaporize.

[0051] 3. Oil and gas condensation, separation and collection stage

[0052] The high-temperature oil vapor evaporated from the top of distiller 1 enters cooler 2 through pipes. Under the action of circulating cooling water, the oil vapor is rapidly condensed into a liquid state.

[0053] A mixture of liquid oil and a small amount of noncondensable gases flows into intermediate converter 4. In intermediate converter 4, gas-liquid separation is performed using gravity. The lower layer of liquid base oil flows through a pipeline into base oil collector 8 for temporary storage and further processing.

[0054] The non-condensable gas separated from the upper layer continues to be drawn away by the vacuum unit 6 via the vacuum converter 5 to ensure that the entire system maintains a stable decompression state throughout the process.

[0055] 4. Exhaust gas treatment stage

[0056] The non-condensable gas (exhaust gas) discharged from vacuum unit 6 first enters exhaust gas collector 7 for buffering and stabilization. Subsequently, under the action of induced draft fan 10, the exhaust gas is sent to the subsequent treatment unit. Depending on the complexity of the exhaust gas composition, it may pass sequentially through scrubbing tank 11 and spray tank 3, where it is scrubbed and sprayed with chemical agents (such as alkali) or water to remove acidic gases, dust, and other impurities. Before entering T0 furnace 13, the treated exhaust gas may first be mixed with air or combustion-supporting gas in mixer 9, and then preheated by exhaust gas preheater 12 to improve combustion efficiency and reduce energy consumption. Finally, the preheated exhaust gas is sent to the high-temperature T0 furnace 13 for complete oxidation and decomposition, generating harmless carbon dioxide and water, which are then discharged after meeting emission standards.

[0057] 5. Slag Removal Stage

[0058] Once the base oil in still 1 has been substantially distilled, stop the electromagnetic heating and stirring. Open the slag discharge valve at the bottom of still 1 to drain the remaining slag oil into the slag oil tank (not shown). This completes one distillation regeneration cycle.

[0059] As can be seen from the above embodiments, this utility model combines efficient internal heating with forced internal circulation and operates under the complete system architecture shown in the attached drawings. It not only solves the core problems of heating efficiency and uniformity, but also provides a complete solution for vacuum maintenance, product collection and exhaust gas treatment, forming a technologically advanced, complete, efficient and environmentally friendly waste oil regeneration system.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of this technical solution, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A waste oil distillation regeneration system based on internal heating and internal circulation, comprising a distiller, a vacuum system, and a condensation collection system, characterized in that, The system also includes: An electromagnetic heating device is installed on the outer wall of the still body and is used to directly heat the still body by induction heating. A dual stirring device is installed inside the still, comprising an outer stirring unit and an inner stirring unit coaxially arranged. The outer stirring unit acts on the region adjacent to the inner wall of the still, while the inner stirring unit acts on the central region of the still. The outer and inner stirring units are configured to work synergistically to drive the feed oil to form a forced internal circulation flow field within the still, transporting the feed oil from the central region to the inner wall of the tank heated by the electromagnetic heating device for heat exchange.

2. The system according to claim 1, characterized in that, The outer agitator is an anchor agitator or a frame agitator.

3. The system according to claim 2, characterized in that, The outer agitator has a scraper on its blades to scrape the inner wall of the distiller, preventing material from coking and enhancing boundary layer heat transfer.

4. The system according to claim 1, characterized in that, The inner agitator is a blade agitator, a propeller agitator, or a turbine agitator, used to generate the main axial flow or radial flow.

5. The system according to claim 1, characterized in that, The design speed of the outer agitator is lower than that of the inner agitator.

6. The system according to claim 5, characterized in that, The outer agitator has a rotational speed range of 30~500 rpm, and the inner agitator has a rotational speed range of 200~3000 rpm.

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