A waste plastic cracking light and heavy oil separation device and separation method

Abstract

The application discloses a waste plastic cracking light-heavy oil separation device, and relates to the technical field of light-heavy oil separation, which comprises a filter, wherein the filter is a sedimentation filter, the inlet of the sedimentation filter is located at the lower part, the outlet is located at the top, the outlet is connected with a vertical gas connecting pipe, the vertical gas connecting pipe is connected with a circulating cooling pump, the circulating cooling medium inlet is arranged at the lower part of the vertical gas connecting pipe, the circulating cooling medium outlet is arranged at the upper part of the vertical gas connecting pipe, the top of the vertical gas connecting pipe is further connected with an inclined straight-through pipe, the lower part of the other end of the inclined straight-through pipe is connected with a cooler, one end connected with the cooler is higher than the other end connected with the vertical gas connecting pipe, the outlet below the cooler is connected with a light oil intermediate tank, the lower end of the inclined straight-through pipe is provided with a temperature sensor one, and the higher end is provided with a temperature sensor two. The light-heavy plastic oil is completely separated, the pipeline and the cooler are prevented from being blocked, the pipeline blockage causes the shutdown and maintenance, the continuous production is realized, and the system safety is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of light and heavy oil separation, and in particular to a light and heavy oil separation device and a separation method for waste plastic cracking. Background Art

[0002] Waste plastic pollution has become an urgent environmental issue. Recycling waste plastics has the potential to save energy, reduce carbon emissions, and boost the economy. Currently, physical and chemical recycling are the primary methods for treating waste plastics. Chemical recycling is particularly suitable for processing low-value, low-purity mixed waste plastics.

[0003] Chemical recycling methods mainly include depolymerization and thermal cracking. Waste plastic cracking oil production technology has been gradually improved with the continuous implementation of policies. On May 31, 2022, the Ministry of Ecology and Environment issued the "Technical Specifications for Waste Plastic Pollution Control" HJ364-2022, which allows waste plastics to be treated by thermal cracking and requires that waste plastic recycling cracking should be continuous production. However, in existing waste plastic cracking oil production technology, incomplete oil separation will cause system pipeline blockage, making it impossible to operate continuously and affecting the safety of the system. Waste plastic oil is of poor quality and has low economic value, resulting in limited industrial applications.

[0004] The Chinese patent with application number CN202011591486.2 adopts ordinary filters for oil and gas separation in waste plastic cracking. Its advantage is that it can realize the filtering function, but its disadvantage is that the filtration is incomplete. There is a risk that ash and heavy oil will enter the subsequent pipelines and equipment along with the oil and gas, clogging the pipelines and equipment, thus causing the problem of inability to produce continuously. Summary of the Invention

[0005] The present invention aims to solve the above-mentioned technical problems and overcome the shortcomings of the prior art, and provides a waste plastic cracking light and heavy oil separation device, comprising a filter, which is a sedimentation filter. The inlet of the sedimentation filter is located at the bottom and the outlet is located at the top. The outlet is connected to a vertical gas connecting pipe, which is connected to a circulating cooling pump. The inlet of the circulating cooling medium is arranged at the bottom of the vertical gas connecting pipe, and the outlet of the circulating cooling medium is arranged at the top of the vertical gas connecting pipe. The top of the vertical gas connecting pipe is also connected to an inclined straight-through pipe, and a cooler is connected below the other end of the inclined straight-through pipe, and the end connected to the cooler is higher than the end connected to the vertical gas connecting pipe. The outlet below the cooler is connected to a light oil intermediate tank, and the lower end of the inclined straight-through pipe is provided with a temperature sensor 1, and the higher end is provided with a temperature sensor 2.

[0006] The technical solution further defined in the present invention is:

[0007] In the aforementioned waste plastic cracking and light and heavy oil separation device, the inner wall of the sedimentation filter is provided with a downwardly inclined baffle plate 1, and the baffle plates 1 are alternately arranged left and right along the height direction.

[0008] In the aforementioned waste plastic cracking and light and heavy oil separation device, the inner wall of the vertical connecting pipe is provided with a second baffle plate inclined downward, and the second baffle plate is alternately arranged left and right along the height direction.

[0009] In the aforementioned waste plastic cracking and light and heavy oil separation device, the inclination angle of the inclined straight-through pipe is 5°-30°.

[0010] In the aforementioned waste plastic cracking and light and heavy oil separation device, the circulating cooling system pipeline can be selected as a straight-through type, a baffle type or a coil type.

[0011] Another object of the present invention is to provide a method for separating light and heavy oils from waste plastic cracking, specifically:

[0012] S1. The mixed oil and gas containing solid particles and dust enters the sedimentation filter from the bottom. The solid particles and dust in the mixed gas are filtered out by the baffle structure inside the sedimentation filter. The remaining oil and gas enter the vertical gas connecting pipe from the top of the sedimentation filter.

[0013] S2. The baffle structure of the vertical gas connecting pipe allows sufficient heat exchange between the gas and the circulating cooling medium. The circulating cooling medium of the circulating cooling pump enters the cooling pipe from the bottom and flows out from the top. The cracked oil and gas are separated into light plastic oil and heavy plastic oil under the action of the circulating cooling system. The condensed heavy plastic oil cleans some of the particulate matter and dust solids in the mixed oil and gas, further purifying the mixed gas.

[0014] S3. Interlocking the temperature of temperature sensor 1 with the amount of cooling medium in the circulating cooling pump, the circulating cooling medium is used to control the oil and gas temperature at the outlet of the vertical gas connecting pipe, condensing the heavy plastic oil, which is then refluxed into the sedimentation filter and rectified in the sedimentation filter, while the light plastic oil and non-condensable cracked gas enter the inclined straight-through pipe;

[0015] S4. The inclined straight pipe connecting to the cooler has an inclination and is equipped with a second temperature sensor on the upper part, so that the very small amount of heavy plastic oil contained in the light plastic oil gas can flow back into the sedimentation filter to avoid blockage of the cooler.

[0016] S5, the plastic cracking oil and gas enters the cooler from the sedimentation filter through the vertical gas connecting pipe and the inclined straight-through pipe for cooling and collection. The oil and gas components entering the cooler are light plastic oil and gas components, of which organic matter C1-C4 is a non-condensable component;

[0017] S6. The condensed light plastic oil enters the light oil intermediate tank, and the non-condensable gas is processed and returned to the cracking gas unit for reuse, providing the system with the heat required for cracking.

[0018] In the aforementioned method for separating light and heavy oils by cracking waste plastics, when the temperature of temperature sensor 1 is higher than 210° C., the amount of circulating cooling medium is increased.

[0019] In the aforementioned method for separating light and heavy oils by cracking waste plastics, when the temperature of the second temperature sensor is higher than 180° C., the amount of circulating cooling medium is increased.

[0020] The beneficial effects of the present invention are:

[0021] (1) This invention controls the oil and gas temperature and uses angled reflux technology to completely separate the light and heavy plastic oils before they enter the pipeline, based on their different solidification points and pour points. This avoids clogging of pipelines and equipment, allowing continuous production. This perfectly solves the problem of separating light and heavy oils from waste plastic cracking, improves system safety and continuous production levels, ensures the quality of light oil, and increases the economic value of the product.

[0022] (2) The vertical gas connecting pipe of the present invention is provided with a gas baffle structure and a circulating cooling device, and the amount of circulating cooling medium is adjusted according to the outlet oil and gas temperature, so that the oil and gas temperature can be controlled;

[0023] (3) The present invention connects the cooler with an inclined straight pipe with an inclination angle of 5°-30° to ensure that the heavy plastic oil can flow back into the filter and does not condense at the bottom of the straight pipe to block the pipeline;

[0024] (4) In the present invention, a temperature sensor 2 is provided at the top of the inclined straight-through pipe, and the amount of cooling medium can be circulated according to the temperature condition of the temperature sensor 2 to ensure that heavy plastic oil does not enter the cooler. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of a waste plastic cracking light and heavy oil separation device;

[0026] Among them: 1. Circulating cooling pump; 2. Circulating cooling medium inlet; 3. Circulating cooling medium outlet; 4. Sedimentation filter; 5. Vertical gas connecting pipe; 6. Inclined straight-through pipe; 7. Cooler; 8. Temperature sensor 1; 9. Temperature sensor 2; 10. Light oil intermediate tank. DETAILED DESCRIPTION

[0027] This embodiment provides a waste plastic cracking light and heavy oil separation device, the structure of which is as follows Figure 1As shown, it includes a filter, which is a sedimentation filter 4. The inner wall of the sedimentation filter 4 is provided with a baffle 1 inclined downward, and the baffle 1 is arranged alternately left and right along the height direction. The inlet of the sedimentation filter 4 is located at the bottom and the outlet is located at the top. Its outlet is connected to a vertical gas connecting pipe 5. The inner wall of the vertical connecting pipe is provided with a baffle 2 inclined downward, and the baffle 2 is arranged alternately left and right along the height direction. The vertical gas connecting pipe 5 is connected to a circulating cooling pump 1, the circulating cooling medium inlet 2 is located at the bottom of the vertical gas connecting pipe 5, and the circulating cooling medium outlet 3 is located at the top of the vertical gas connecting pipe 5. The circulating cooling system pipeline can be selected from a straight-through type, a baffle type or a coil type. The top of the vertical gas connecting pipe 5 is also connected to an inclined straight-through pipe 6, and the other end of the inclined straight-through pipe 6 is connected to a cooler 7 below, and the end connected to the cooler 7 is higher than the end connected to the vertical gas connecting pipe 5, with an inclination angle of 5°-30°. The lower outlet of the cooler 7 is connected to a light oil intermediate tank 10, and the lower end of the inclined straight pipe 6 is provided with a temperature sensor 1 8, and the upper end is provided with a temperature sensor 2 9.

[0028] The above device is used to separate light and heavy oils from waste plastic cracking:

[0029] The mixed oil and gas containing solid particles and dust enters the sedimentation filter 4 from the bottom of the sedimentation filter 4. The sedimentation filter 4 is provided with a baffle structure to filter out the solid particles and dust in the mixed gas. The remaining oil and gas enters the vertical gas connecting pipe 5 from the top of the sedimentation filter 4.

[0030] The vertical gas connecting pipe 5 is equipped with a baffle structure to ensure efficient heat exchange between the gas and the circulating cooling medium. The cracked oil and gas are separated into light plastic oil and heavy plastic oil by the circulating cooling system. The condensed heavy plastic oil removes some solid matter, such as particulate matter and dust, from the mixed oil and gas, further purifying the mixed gas. The circulating cooling medium enters the cooling pipe from the bottom and exits from the top using the circulating cooling pump 1. The circulating cooling system piping can be selected from straight-through, baffled, and coil types.

[0031] Based on the temperature of temperature sensor 8 at the top of vertical gas connecting pipe 5, the temperature of temperature sensor 8 is interlocked with the amount of cooling medium output from circulating cooling pump 1. When the temperature exceeds 210°C, the cooling medium supply is increased to ensure effective cooling. The circulating cooling medium controls the temperature of the oil and gas at the outlet of vertical gas connecting pipe 5, condensing the heavy plastic oil. The oil then flows back into sedimentation filter 4, where it undergoes distillation, improving its quality. Light plastic oil and non-condensable cracked gas enter inclined straight pipe 6.

[0032] The inclined straight pipe 6 connecting to the cooler 7 is angled and has a temperature sensor 9 installed at its top. The displayed temperature is required to be below 180°C. If it exceeds 180°C, the circulating cooling medium volume is increased to ensure separation efficiency. This allows the small amount of heavy plastic oil entrained in the light plastic oil vapor to flow back into the sedimentation filter 4, preventing clogging of the cooler 7.

[0033] The plastic cracking oil and gas enters the cooler 7 from the sedimentation filter 4 through the vertical gas connecting pipe 5 and the inclined straight pipe 6 for cooling and collection. The oil and gas components entering the cooler 7 are light plastic oil and gas components, among which organic matter C1-C4 are non-condensable components.

[0034] The condensed light plastic oil enters the light oil intermediate tank 10, and the non-condensable gas is recycled to the cracking gas unit after treatment to provide the system with the heat required for cracking.

[0035] In addition to the above embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection required by the present invention.

Claims

1. A waste plastic cracking light and heavy oil separation device, comprising a filter, characterized in that: The filter is a sedimentation filter (4), the inlet of the sedimentation filter (4) is located at the bottom and the outlet is located at the top, the outlet is connected to a vertical gas connecting pipe (5), the vertical gas connecting pipe (5) is connected to a circulating cooling pump (1), the circulating cooling medium inlet (2) is located at the bottom of the vertical gas connecting pipe (5), the circulating cooling medium outlet (3) is located at the top of the vertical gas connecting pipe (5), the top of the vertical gas connecting pipe (5) is further connected to an inclined straight pipe (6), the other end of the inclined straight pipe (6) is connected to a cooler (7) below, and the end connected to the cooler (7) is higher than the end connected to the vertical gas connecting pipe (5), the outlet below the cooler (7) is connected to a light oil intermediate tank (10), the lower end of the inclined straight pipe (6) is provided with a temperature sensor 1 (8), and the upper end is provided with a temperature sensor 2 (9).

2. The waste plastic cracking and light and heavy oil separation device according to claim 1, characterized in that: The inner wall of the sedimentation filter (4) is provided with a baffle plate 1 inclined downward, and the baffle plate 1 is alternately arranged left and right along the height direction.

3. A waste plastic cracking and light and heavy oil separation device according to claim 1 or 2, characterized in that: The inner wall of the vertical connecting pipe is provided with a second baffle plate inclined downward, and the second baffle plate is alternately arranged left and right along the height direction.

4. The waste plastic cracking and light and heavy oil separation device according to claim 1, characterized in that: The inclination angle of the inclined straight-through pipe (6) is 5°-30°.

5. The waste plastic cracking and light and heavy oil separation device according to claim 1, characterized in that: The circulating cooling system pipeline can be selected as straight-through type, baffle type or coil type.

6. A method for separating light and heavy oils by cracking waste plastics, characterized by: The separation device according to any one of claims 1 to 5 is applied, specifically: S1, the mixed oil and gas containing solid particles and dust enters the interior from the lower part of the sedimentation filter (4), and the solid particles and dust in the mixed gas are filtered out by the baffle structure in the sedimentation filter (4), and the remaining oil and gas enters the vertical gas connecting pipe (5) from the top of the sedimentation filter (4); S2, the baffle structure of the vertical gas connecting pipe (5) allows the gas and the circulating cooling medium to fully exchange heat. The circulating cooling medium of the circulating cooling pump (1) enters from the lower part of the cooling pipe and flows out from the upper part. The cracked oil and gas are separated into light plastic oil and heavy plastic oil under the action of the circulating cooling system. The condensed heavy plastic oil cleans part of the particulate matter and dust solid part in the mixed oil and gas, further purifying the mixed gas. S3, interlocking the temperature of the temperature sensor 1 (8) and the amount of cooling medium of the circulating cooling pump (1), controlling the oil and gas temperature at the outlet of the vertical gas connecting pipe (5) with the circulating cooling medium, condensing the heavy plastic oil, returning it to the sedimentation filter (4) and performing rectification in the sedimentation filter (4), and the light plastic oil and the non-condensable cracked gas entering the inclined straight pipe (6); S4, the inclined straight pipe (6) connected to the cooler (7) has an inclination angle and is provided with a second temperature sensor (9) at the top, so that a small amount of heavy plastic oil entrained in the light plastic oil gas flows back into the sedimentation filter (4), thereby avoiding clogging of the cooler (7); S5, the plastic cracking oil and gas enters the cooler (7) from the sedimentation filter (4) through the vertical gas connecting pipe (5) and the inclined straight pipe (6) for cooling and collection. The oil and gas components entering the cooler (7) are light plastic oil and gas components, of which organic matter C1-C4 are non-condensable components; S6. The condensed light plastic oil enters the light oil intermediate tank (10), and the non-condensable gas is processed and then returned to the cracking gas unit for reuse, providing the system with the heat required for cracking.

7. The method for separating light and heavy oils by cracking waste plastics according to claim 6, wherein: When the temperature of temperature sensor 1 (8) is higher than 210°C, increase the amount of circulating cooling medium.

8. The method for separating light and heavy oils by cracking waste plastics according to claim 6 or 7, characterized in that: When the temperature of temperature sensor 2 (9) is higher than 180°C, increase the amount of circulating cooling medium.

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