Separation device and method for waste plastic pyrolysis oil gas

Abstract

The invention discloses a separation device and method for waste plastic pyrolysis oil gas, and relates to the field of waste plastic resource utilization. The separation device for the waste plastic pyrolysis oil gas comprises a fractionating tower, wherein the fractionating tower comprises a tower kettle and a fractionating main body which are sequentially arranged from bottom to top; the multiple layers of tower plates are sequentially arranged in the fractionation main body from bottom to top, and side line extraction openings are formed in the tower plates; and the solvent oil extraction assembly comprises a solvent oil extraction pipeline, and a plurality of side line extraction ports positioned on different tower plates are alternatively connected with the solvent oil extraction pipeline. According to the invention, through mass transfer and heat transfer of the tower plate, the solvent oil with larger average molecular weight is left on the tower plate, and the higher the tower plate is, the larger the average molecular weight of the solvent oil on the tower plate is, so that when the solvent oil with different average molecular weights needs to be extracted, the extraction efficiency is greatly improved. And the solvent oil extraction pipeline of the solvent oil extraction assembly is only required to be connected with the side line extraction ports on different tower plates, so that the separation device for the waste plastic pyrolysis oil gas can extract products with specific average molecular weight.

Description

Technical Field

[0001] The present invention relates to the field of waste plastic resource utilization, and particularly to a separation device and method for waste plastic pyrolysis oil and gas. Background Art

[0002] Waste plastics are chemically stable and difficult to degrade naturally. After being landfilled, waste plastics will gradually decompose into micron- or even nanoscale particles, which will enter the food chain through soil, groundwater systems, or marine ecosystems, etc., and will ultimately endanger human health through the enrichment effect of the food chain. Incineration of waste plastics is an alternative to landfilling. Toxic substances such as furans, dioxins, and nitrogen oxides are released or generated during the incineration of waste plastics, and a large amount of plastic particles are produced. These harmful substances and plastic particles will disrupt the balance of the ecosystem.

[0003] Pyrolysis (thermal pyrolysis or catalytic pyrolysis) of waste plastics to produce plastic oil is a promising energy-saving and environmentally friendly waste plastic resource utilization method, which can effectively replace the landfilling and incineration of waste plastics. However, the pyrolysis products of waste plastics are a complex mixture (mainly hydrocarbons), and the efficient separation of this mixture is an important factor affecting the economy of waste plastic pyrolysis recovery.

[0004] Some separation methods for waste plastic pyrolysis products already exist in the prior art. For example, the invention patent with the publication number: CN103980938A discloses a method for producing clean fuel from chlorine-containing plastic oil, belonging to the fields of environmental protection and energy technology. Its characteristics are that the chlorine-containing plastic oil is injected into a catalytic distillation column equipped with a molecular sieve / aluminum oxide catalyst for reaction and rectification; after catalytic cracking, the chlorine-containing plastic oil enters a low-pressure liquid-phase hydrogenation column through heat exchange for hydrogenation dechlorination, and the catalyst used is a supported metal catalyst; the fraction oil after liquid-phase hydrogenation enters a water washing tower, the lower water phase at the bottom of the tower is circulated, and the upper fraction oil phase after water washing enters a hydrofining column under pressure. The catalyst used for hydrofining is a sulfide catalyst. Through the hydrogenation saturation reaction of monoolefins, monoolefin compounds are removed, and sulfur, nitrogen, and gum are removed to produce odorless and high-quality gasoline and diesel mixed oil, which is then distilled to obtain gasoline and diesel fraction oils, and the heavy oil at the bottom of the tower is mixed with the raw material chlorine-containing plastic oil for re-reaction. The present invention has the advantages of simple process, high catalyst activity and selectivity, and good economic benefits and industrial application prospects.

[0005] However, the products obtained after the separation of existing waste plastic pyrolysis oil and gas are of a single type and cannot be effectively controlled, and it is impossible to extract products with a specific average molecular weight according to actual needs (the average molecular weight of a solvent oil refers to the weighted average of the molecular weights of all components in its composition. Since a solvent oil is a mixture composed of various hydrocarbons, such as alkanes, cycloalkanes, aromatics, etc., and the molecular weights of each component are different, it is necessary to use the average molecular weight to characterize its overall properties). Summary of the invention

[0006] In view of the defects in the prior art, the technical problem solved by the present invention is: how to extract a product with a specific average molecular weight.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a separation device for waste plastic pyrolysis oil and gas, comprising: The fractionation tower comprises a tower kettle and a fractionation body arranged in sequence from bottom to top; A particle removal assembly is disposed inside the tower kettle; Multiple layers of trays are sequentially arranged inside the fractionation body from bottom to top, and each tray is provided with a side line extraction port; The solvent oil extraction component comprises a solvent oil extraction pipeline, and a plurality of side line extraction ports located on different tower plates are selectively connected to the solvent oil extraction pipeline.

[0008] By adopting the above technical scheme, the oil and gas that have been desuperheated and washed with solid particles by the particle removal component enter the distillation body, pass through layer by layer of tower plates, and through mass transfer and heat transfer of the tower plates, the solvent oil with a larger average molecular weight is retained on the tower plates because the larger the average molecular weight of the solvent oil is, the higher its boiling point is. The higher the tower plate is, the larger the average molecular weight of the solvent oil on it is. Therefore, when it is necessary to extract solvent oils of different average molecular weights, it is only necessary to connect the solvent oil extraction pipeline of the solvent oil extraction component to the side line extraction outlets on different tower plates. Therefore, the waste plastic cracking oil and gas separation device can extract products with specific average molecular weights.

[0009] In combination with the first aspect, in one embodiment, the particle removal component includes bottom liquid, a herringbone plate, a liquid distributor and a bottom liquid extraction component, the bottom liquid, the herringbone plate and the liquid distributor are arranged in sequence inside the bottom of the tower from bottom to top, and the bottom liquid is located at the bottom of the tower bottom, the liquid distributor is located at the top of the tower bottom, the bottom liquid extraction pipeline of the bottom liquid extraction component is connected to the extraction port of the bottom liquid, and the bottom liquid reflux pipeline of the bottom liquid extraction component is connected to the liquid distributor, so that the liquid distributor can spray the bottom liquid onto the herringbone plate.

[0010] By adopting the above technical solution, on the one hand, the rising oil and gas can be desuperheated by means of mass transfer and heat transfer, and on the other hand, the solid particles entrained by the rising oil and gas can be washed away.

[0011] In one embodiment, the solvent oil extraction component also includes a solvent oil extraction pump, a solvent oil cooler, a solvent oil alkali washing tank, a solvent oil temporary storage tank, a solvent oil delivery pump and a solvent oil storage tank which are sequentially connected through pipelines. The solvent oil extraction pump is connected to the side line extraction outlet through the solvent oil extraction pipeline, and the solvent oil storage tank is connected to the first tank truck through the solvent oil output pump to realize the delivery of the solvent oil on the tower plate to the first tank truck.

[0012] By adopting the above technical solution, the solvent oil extracted from the tower plate is deacidified to form a product, which is then sent to the first tank truck, and the product is transported to a designated location by the first tank truck.

[0013] In a second aspect, the present invention provides a method for separating oil and gas from waste plastic pyrolysis, which comprises the following steps: Providing a separation device for waste plastic cracking oil and gas; The gasoline mixture obtained by the pyrolysis reaction of the waste plastic is input into the interior of the tower kettle; The rising oil and gas are desuperheated and the solid particles entrained in the oil and gas are washed by the particle removal component; Mass and heat transfer is carried out through the trays, wherein the average molecular weight of the solvent oil on the trays on the upper layer is smaller than that on the trays on the lower layer; Multiple side line extraction ports located on different tower plates are selectively connected to the solvent oil extraction pipeline to extract solvent oils with different average molecular weights.

[0014] By adopting the above technical scheme, the oil and gas that have been desuperheated and washed with solid particles by the particle removal component enter the distillation body, pass through layer by layer of tower plates, and through mass transfer and heat transfer of the tower plates, the solvent oil with a larger average molecular weight is retained on the tower plates because the larger the average molecular weight of the solvent oil is, the higher its boiling point is. The higher the tower plate is, the larger the average molecular weight of the solvent oil on it is. Therefore, when it is necessary to extract solvent oils of different average molecular weights, it is only necessary to connect the solvent oil extraction pipeline of the solvent oil extraction component to the side line extraction outlets on different tower plates. Therefore, the waste plastic cracking oil and gas separation device can extract products with specific average molecular weights.

[0015] In conjunction with the second aspect, in one embodiment, the separation method further comprises: The light hydrocarbons and water at the top of the fractionation body are separated from the top of the tower and enter the top condenser; Condensation is performed through the top condenser to separate light hydrocarbons and water into an uncondensed gas phase and a condensed liquid phase; The uncondensed gas phase enters the subsequent processing section; The condensed liquid phase enters the light solvent oil condensate tank, and phase separation is performed to obtain light solvent oil and waste water; Discharge wastewater into wastewater storage tanks; The light solvent oil is put into the light solvent oil alkali washing tank and subjected to deacidification treatment; The deacidified light solvent oil is put into the light solvent oil temporary storage tank; The light solvent oil in the light solvent oil temporary storage tank is pressurized by a light solvent oil delivery pump and delivered to the light solvent oil storage tank; The light solvent oil in the light solvent oil storage tank is pressurized by the light solvent oil output pump and output to the second tank truck.

[0016] By adopting the above technical solution, light hydrocarbons and moisture are condensed to obtain uncondensed gas phase and condensed liquid phase. The uncondensed gas phase can be subjected to subsequent treatment, and the condensed liquid phase can be separated into solvent oil with a relatively small molecular weight and subjected to deacidification treatment to form another product, which is sent to the second tanker. The product is transported to the designated location by the second tanker. Therefore, the separation device for waste plastic pyrolysis oil and gas can produce products with different average molecular weights simultaneously.

[0017] In one embodiment, the entry of the uncondensed gas phase into the subsequent treatment section specifically includes: The uncondensed gas phase enters the liquid ring compressor from the top condenser and is compressed to form a gas phase and a liquid phase; The gas phase and the liquid phase are separated by a gas-liquid separator; The gas phase is made into fuel; The liquid phase is subjected to condensate stratification to form an oil phase and waste water; The oil phase is sent to the light solvent oil condensate tank, and the waste water is sent to the waste water storage tank.

[0018] By adopting the above technical solution, the oil phase can be separated from the uncondensed gas phase and transported to the second tanker together with the light solvent oil; at the same time, the gas phase that cannot be condensed all the time can be made into fuel.

[0019] In one embodiment, the making of the gas phase into fuel specifically includes: The gas phase enters the non-condensable gas caustic scrubber; Through the non-condensable gas caustic scrubber, deacidification treatment is carried out to form fuel.

[0020] By adopting the above technical solution, the gas phase that cannot be condensed all the time can be made into fuel and put into the lava furnace to improve the waste utilization rate.

[0021] In one embodiment, the entry of the uncondensed gas phase into the subsequent treatment section further includes: A working fluid cooler is arranged between the liquid ring compressor and the gas-liquid separator; The working fluid entering the liquid ring compressor is cooled by the working fluid cooler.

[0022] By adopting the above technical solution, the temperature of the working fluid entering the liquid ring compressor can be adjusted to be within a reasonable range, so as to improve the working efficiency of the liquid ring compressor.

[0023] In one embodiment, the separation method further includes: Select two different trays, which are respectively recorded as the upper tray and the lower tray; Extract the hydrocarbon mixture from the lower tray; Pressurize the hydrocarbon mixture through a circulation pump and send it to a circulation cooler; Cool the hydrocarbon mixture through the circulation cooler; Return the cooled hydrocarbon mixture to the upper tray.

[0024] By adopting the above technical solution, an intermediate cooler can be provided for the fractionating tower, the refrigerant can be utilized in stages, and steam of different specifications can be by-produced, thereby saving the energy consumption of the separation device for waste plastic pyrolysis oil and gas.

[0025] In one embodiment, after entraining the solid particles in the washing oil and gas, it further includes: The solid particles precipitate to the bottom of the tower kettle to form recycled oil; Withdraw the recycled oil from the bottom of the tower kettle; Pressurize the recycled oil through a recycled oil transfer pump and send it to the waste plastic pyrolysis equipment; Perform secondary pyrolysis on the recycled oil through the waste plastic pyrolysis equipment to form fuel.

[0026] By adopting the above technical solution, the recycled oil can be made into fuel and put into the lava furnace, further improving the waste utilization rate.

[0027] In summary, the present invention includes at least one of the following beneficial technical effects: 1. The oil and gas that is de-superheated and washes the solid particles through the particle removal component enters the fractionation main body, passes through layer upon layer of trays. Through the mass transfer and heat transfer of the trays, since the higher the average molecular weight of the solvent oil, the higher its boiling point, the solvent oil with a larger average molecular weight is left on the tray. The higher the tray, the larger the average molecular weight of the solvent oil on it. Therefore, when it is necessary to withdraw solvent oils with different average molecular weights, only need to connect the solvent oil withdrawal pipeline of the solvent oil withdrawal component to the side line withdrawal ports on different trays. Therefore, the separation device for waste plastic pyrolysis oil and gas can withdraw products with a specific average molecular weight; 2. Through the design of the particle removal component, on the one hand, it functions to de-superheat the rising oil and gas through mass transfer and heat transfer, and on the other hand, it functions to wash away the solid particles entrained in the rising oil and gas; 3. Through the design of the pipeline, not only can more light solvent oil be separated, but also the gas phase that cannot be condensed all the time and the recycled oil can be utilized as waste, improving the waste utilization rate of the separation device for waste plastic pyrolysis oil and gas. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of the separation device for waste plastic pyrolysis oil and gas according to an embodiment of the present invention; Figure 2 It is a flowchart of the separation method for waste plastic pyrolysis oil and gas according to an embodiment of the present invention.

[0029] In the figure: 1 - fractionating tower, 101 - tower kettle, 102 - fractionating main body, 103 - herringbone plate, 104 - tray, 105 - side draw outlet, 106 - liquid distributor, 2 - tower kettle liquid extraction assembly, 201 - tower kettle liquid extraction pump, 202 - tower kettle liquid cooler, 203 - tower kettle liquid reflux pipeline, 3 - solvent oil extraction assembly, 301 - solvent oil extraction pipeline, 302 - solvent oil extraction pump, 303 - solvent oil cooler, 304 - solvent oil caustic scrubbing tank, 305 - solvent oil temporary storage tank, 306 - solvent oil transfer pump, 307 - solvent oil storage tank, 308 - solvent oil output pump, 309 - first tanker, 4 - overhead condenser, 5 - solvent oil condensate tank, 6 - light solvent oil caustic scrubbing tank, 7 - light solvent oil temporary storage tank, 8 - light solvent oil transfer pump, 9 - light solvent oil storage tank, 10 - light solvent oil output pump, 11 - second tanker, 12 - liquid ring compressor, 13 - gas-liquid separator, 14 - non-condensable gas caustic scrubbing tower, 15 - caustic scrubbing tower pump, 16 - caustic scrubbing tower cooler, 17 - wastewater treatment device, 18 - working fluid cooler, 19 - gas phase equilibrium pipe, 20 - wastewater storage tank, 21 - wastewater output pump, 22 - pyrolysis reactor, 23 - recycle oil transfer pump, 24 - tower kettle liquid temporary storage tank, 25 - circulation pump, 26 - circulation cooler. Specific embodiments

[0030] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] For the waste plastic pyrolysis oil-gas separation device in the embodiments of the present invention, as shown in Figure 1 the figure, the waste plastic pyrolysis oil-gas separation device includes a fractionating tower 1, which includes a tower kettle 101 and a fractionating main body 102 arranged in sequence from bottom to top; a particle removal assembly is arranged inside the tower kettle 101; a plurality of trays 104 are arranged in sequence from bottom to top inside the fractionating main body 102, and side draw outlets 105 are arranged on each tray 104. One side draw outlet 105 can be arranged on one tray 104, or multiple side draw outlets 105 can be arranged; the solvent oil extraction assembly 3 includes a solvent oil extraction pipeline 301, and the side draw outlets 105 located on different trays 104 are selectively connected to the solvent oil extraction pipeline 301.

[0032] It can be seen from this that the oil-gas mixture coming out of the waste plastic pyrolysis reactor 22 in the present invention enters the interior of the tower kettle 101. This oil-gas mixture can be superheated oil-gas, thus avoiding the cooling medium or energy consumed when the pyrolysis oil-gas needs to be condensed first and then fed. At the same time, the superheated gaseous feeding method enables the tower kettle 101 not to be provided with a reboiler. During the rising process of the oil-gas in the tower kettle 101, the solid particles such as ash entrained in the oil-gas are first washed off by the particle removal component, and the washed oil-gas enters the fractionation main body 102. Mass transfer and heat transfer are carried out between the oil-gas and the descending liquid phase through the layers of trays 104 in the fractionation main body 102, and a side line draw-off port 105 is reserved on the tray 104. According to actual requirements, the side line draw-off ports 105 located on different trays 104 are selectively connected to the solvent oil draw-off pipeline 301 of the solvent oil draw-off component 3 to draw off the solvent oil on this tray 104. Since the higher the average molecular weight of the solvent oil, the higher its boiling point, the solvent oil with a larger average molecular weight is left on the tray 104. The higher the tray 104, the larger the average molecular weight of the solvent oil on it. Therefore, when it is necessary to draw off solvent oils with different average molecular weights, only the solvent oil draw-off pipeline 301 of the solvent oil draw-off component 3 needs to be connected to the side line draw-off ports 105 on different trays 104. Therefore, the separation device for waste plastic pyrolysis oil-gas can draw off products with a specific average molecular weight.

[0033] Preferably, a specific structure of the particle removal component is provided: The particle removal component includes the tower kettle liquid 101, the herringbone plate 103, the liquid distributor 106 and the tower kettle liquid draw-off component 2. The tower kettle liquid 101, the herringbone plate 103 and the liquid distributor 106 are sequentially arranged inside the tower kettle 101 from bottom to top. The tower kettle liquid 101 is located at the bottom of the tower kettle 101, and the liquid distributor 106 is located at the top of the tower kettle 101. The tower kettle liquid draw-off pipeline of the tower kettle liquid draw-off component 2 is connected to the draw-off port of the tower kettle liquid 101, and the tower kettle liquid return pipeline 203 of the tower kettle liquid draw-off component 2 is connected to the liquid distributor 106 to enable the liquid distributor 106 to spray the tower kettle liquid 101 onto the herringbone plate 103; The tower kettle liquid draw-off component 2 includes a tower kettle liquid draw-off pipeline, a tower kettle liquid draw-off pump 201, a tower kettle liquid cooler 202 and a tower kettle liquid return pipeline 203 connected in sequence.

[0034] Specifically, a draw-off port near the bottom of the reboiler 101 is connected to the reboiler 101 liquid draw-off pipeline, and a stream of reboiler 101 liquid is drawn out, pressurized by the reboiler liquid draw-off pump 201 and sent to the reboiler liquid cooler 202. The cooled reboiler 101 liquid returns to the reboiler 101 in two paths: one path returns to the reboiler 101 above the liquid level of the reboiler 101; the other path enters the reboiler 101 through the pipe orifice above the chevron plate 103 and enters the liquid distributor 106, and is evenly sprayed on the chevron plate 103 through the liquid distributor 106. During the process that the refluxed reboiler 101 liquid falls into the reboiler 101 through multiple chevron plates 103, it comes into contact with the rising superheated oil and gas. Therefore, the structural design of the particle removal component serves two purposes: on the one hand, it de-superheats the rising oil and gas through mass transfer and heat transfer, and on the other hand, it washes away the solid particles entrained in the rising oil and gas.

[0035] Preferably, a specific structure of the solvent oil draw-off component 3 is provided: The solvent oil draw-off component 3 further includes a solvent oil draw-off pump 302, a solvent oil cooler 303, a solvent oil caustic scrubber 304, a solvent oil temporary storage tank 305, a solvent oil transfer pump 306 and a solvent oil storage tank 307 connected in sequence through pipelines. The solvent oil draw-off pump 302 is connected to the side draw-off port 105 through the solvent oil draw-off pipeline 301. The solvent oil storage tank 307 is connected to the first tanker 309 through the solvent oil output pump 308 to realize the transportation of the solvent oil on the tray 104 to the first tanker 309.

[0036] Specifically, one end of the solvent oil draw-off pipeline 301 is connected to the side draw-off port 105, and the other end is connected to the input end of the solvent oil draw-off pump 302. The drawn solvent oil is pressurized by the solvent oil draw-off pump 302 and sent to the solvent oil cooler 303 for cooling. A reflux pipeline is arranged on the pipeline between the solvent oil draw-off pump 302 and the solvent oil cooler 303, and the other end of this reflux pipeline is connected to the side draw-off port 105 of another tray 104, so as to adjust the amount of solvent oil sent to the solvent oil cooler 303; the cooled solvent oil enters the solvent oil caustic scrubber 304 for deacidification treatment to form a product, and the wastewater generated during this process is discharged into the wastewater storage tank 20; the deacidified solvent oil enters the solvent oil temporary storage tank 305 for temporary storage, and a gas-phase balance pipe 19 is arranged between the solvent oil caustic scrubber 304 and the solvent oil temporary storage tank 305; the solvent oil in the solvent oil temporary storage tank 305 is pressurized by the solvent oil transfer pump 306 and sent to the solvent oil storage tank 307; finally, the solvent oil in the solvent oil storage tank 307 is pressurized by the solvent oil output pump 308 and sent to the first tanker 309, and is transported to the designated location through the first tanker 309.

[0037] The method for separating waste plastic pyrolysis oil and gas in the embodiments of the present invention, refer to Figure 1 、 2 As shown, it includes the following steps: Provide a separation device for cracked oil and gas from waste plastics; Input the gasoline mixture obtained from the pyrolysis reaction of waste plastics into the interior of the column kettle 101; Remove superheat from the ascending oil and gas through the particle removal component, and wash the solid particles entrained in the oil and gas; Perform mass transfer and heat transfer through the tray 104, wherein the average molecular weight of the solvent oil on the relatively upper tray 104 is smaller than that on the relatively lower tray 104; Selectively connect the side draw outlets 105 on multiple different trays 104 to the solvent oil extraction pipeline 301 of the solvent oil extraction component 3 to extract solvent oils with different average molecular weights.

[0038] It can be seen therefrom that in the present invention, the oil and gas mixture coming out of the waste plastic pyrolysis reactor 22 enters the interior of the column kettle 101, and this oil and gas mixture can be superheated oil and gas, thus avoiding the cooling medium or energy consumed by the need to first condense the pyrolysis oil and gas and then feed it. At the same time, the superheated gaseous feed method enables the column kettle 101 not to be provided with a reboiler; during the upward movement of the oil and gas in the column kettle 101, first, the solid particles such as ash entrained in the oil and gas are washed away through the particle removal component, and the washed oil and gas enter the fractionation main body 102; mass transfer and heat transfer are carried out between the trays 104 layer by layer in the fractionation main body 102 and the descending liquid phase, and side draw outlets 105 are reserved on the trays 104; according to actual requirements, the side draw outlets 105 on multiple different trays 104 are selectively connected to the solvent oil extraction pipeline 301 of the solvent oil extraction component 3 to extract the solvent oil on this tray 104; because the higher the average molecular weight of the solvent oil, the higher its boiling point, the solvent oil with a larger average molecular weight is left on the tray 104, and the higher the tray 104, the larger the average molecular weight of the solvent oil on it. Therefore, when it is necessary to extract solvent oils with different average molecular weights, only the solvent oil extraction pipeline 301 of the solvent oil extraction component 3 needs to be connected to the side draw outlets 105 on different trays 104. Therefore, the separation device for cracked oil and gas from waste plastics can extract products with a specific average molecular weight.

[0039] Preferably, the separation method further includes: Separate the light hydrocarbons and water at the top of the fractionation main body 102 from the top of the tower and enter the top condenser 4; Condense through the top condenser 4 to divide the light hydrocarbons and water into uncondensed gas phase and condensed liquid phase; Feed the uncondensed gas phase into the subsequent treatment section; Feed the condensed liquid phase into the light solvent oil condensate tank 5 to perform phase separation to obtain light solvent oil and wastewater; Discharge the wastewater into the wastewater storage tank 20; Feed the light solvent oil into the light solvent oil caustic washing tank 6 and perform deacidification treatment; The light solvent oil after deacidification enters the light solvent oil temporary storage tank 7; The light solvent oil in the light solvent oil temporary storage tank 7 is pressurized by the light solvent oil transfer pump 8 and transported to the light solvent oil storage tank 9; The light solvent oil in the light solvent oil storage tank 9 is pressurized by the light solvent oil output pump 10 and output to the second tanker 11.

[0040] It should be noted that the solvent oil is divided into light solvent oil and heavy solvent oil according to the average molecular weight. The light solvent oil has a lower boiling point, usually between 30°C and 200°C, and is volatile; the heavy solvent oil has a higher boiling point, usually between 200°C and 400°C, and has lower volatility.

[0041] Specifically, the light hydrocarbons and water after removing the heavy components (with a larger average molecular weight) are discharged from the top of the tower and enter the top condenser 4 through a pipeline. Condensation is carried out through the top condenser 4. Due to different distillation ranges, an uncondensed gas phase and a condensed liquid phase will be formed. The uncondensed gas phase first passes through the light solvent oil condensate tank 5 and then enters the subsequent treatment section; the condensed liquid phase enters the light solvent oil condensate tank 5, and light solvent oil and wastewater are obtained through phase separation. The wastewater is discharged into the wastewater storage tank 20 through a pipeline, and the wastewater is sent into the wastewater treatment device 17 by the wastewater output pump 21; the light solvent oil obtained through phase separation enters the light solvent oil caustic scrubbing tank 6 and undergoes deacidification treatment. The light solvent oil after deacidification in the light solvent oil caustic scrubbing tank 6 enters the light solvent oil temporary storage tank 7; Gas phase balance pipes 19 are provided between the light solvent oil condensate tank 5, the light solvent oil caustic scrubbing tank 6, the light solvent oil temporary storage tank 7 and the wastewater storage tank 20 to avoid unbalanced air pressure from affecting normal operation; the light solvent oil in the light solvent oil temporary storage tank 7 is pressurized by the light solvent oil transfer pump 8 and transported to the light solvent oil storage tank 9; the light solvent oil in the light solvent oil storage tank 9 is pressurized by the light solvent oil output pump 10 and output to the second tanker 11, and the product is transported to the designated location through the second tanker 11. Therefore, the separation device for waste plastic pyrolysis oil and gas can simultaneously produce products with different average molecular weights.

[0042] Similarly, multiple different trays 104 can be selected on the fractionation main body 102, and solvent oil extraction components 3 are provided at the side line extraction outlets 105 of the selected trays 104 to further produce products with different average molecular weights.

[0043] Furthermore, the uncondensed gas phase enters the subsequent treatment section, specifically including: The uncondensed gas phase enters the liquid ring compressor 12 from the top condenser 4 and is compressed to form a gas phase and a liquid phase; The gas phase and the liquid phase are separated by the gas-liquid separator 13; The gas phase is made into fuel; The liquid phase is subjected to condensate stratification to form an oil phase and wastewater; The oil phase is sent to the light solvent oil condensate tank 5, and the wastewater is sent to the wastewater storage tank 20.

[0044] Specifically, the uncondensed gas phase enters the liquid ring compressor 12 from the top condenser 4 and is compressed to form a gas phase and a liquid phase. Then it enters the gas-liquid separator 13, where the gas phase and the liquid phase are separated. The gas phase is discharged into the subsequent treatment device to make fuel; the liquid phase is subjected to condensate stratification in the gas-liquid separator 13 to form an oil phase and wastewater. The wastewater is discharged into the wastewater storage tank 20, and the oil phase is sent to the light solvent oil condensate tank 5 through a pipeline. The uncondensed gas phase can be separated from the oil phase and transported to the second tanker 11 together with the light solvent oil; at the same time, the gas phase that can never be condensed can be made into fuel.

[0045] Further, the uncondensed gas phase entering the subsequent treatment section further includes: A working fluid cooler 18 is provided between the liquid ring compressor 12 and the gas-liquid separator 13; The working fluid entering the liquid ring compressor 12 is cooled by the working fluid cooler 18.

[0046] Specifically, the input end of the working fluid cooler 18 is connected to the gas-liquid separator 13, and the output end of the working fluid cooler 18 is connected to the liquid ring compressor 12. After the working fluid is cooled by the working fluid cooler 18, it enters the liquid ring compressor 12 to adjust the temperature of the working fluid entering the liquid ring compressor 12 to make its temperature within a reasonable range, thereby improving the working efficiency of the liquid ring compressor 12.

[0047] Preferably, making the gas phase into fuel specifically includes: The gas phase enters the non-condensable gas caustic scrubber 14; The acid removal treatment is carried out through the non-condensable gas caustic scrubber 14 to form fuel.

[0048] Specifically, the gas phase in the gas-liquid separator 13 is discharged into the bottom of the non-condensable gas caustic scrubber 14, and the acid removal treatment is carried out through the non-condensable gas caustic scrubber 14. At the same time, a cooling device is also provided on the non-condensable gas caustic scrubber 14. The cooling device includes a caustic scrubber pump 15 and a caustic scrubber cooler 16. The gas phase after the acid removal treatment is discharged from the top of the non-condensable gas caustic scrubber 14 and put into the lava furnace to improve the waste utilization rate.

[0049] Further, another pipeline is connected between the liquid ring compressor 12 and the gas-liquid separator 13 to adjust the rate at which the gas phase in the gas-liquid separator 13 is discharged into the non-condensable gas caustic scrubber 14.

[0050] Preferably, the separation method further includes: Select two trays 104 of different layers, denoted as the upper tray 104 and the lower tray 104 respectively; Withdraw the hydrocarbon mixture from the lower tray 104; Pressurize the hydrocarbon mixture by the circulating pump 25 and send it to the circulating cooler 26; Cool the hydrocarbon mixture through the circulating cooler 26; Return the cooled hydrocarbon mixture to the upper tray 104.

[0051] Specifically, the above design is denoted as a circulating cooling device. Multiple circulating cooling devices can be designed on the fractionation main body 102, preferably two. Among them, the higher the position of the circulating cooling device on the fractionation main body 102, the lower the temperature of the withdrawn hydrocarbon mixture. Therefore, the refrigerant can be utilized in stages, and steam of different specifications can be by-produced, thereby saving the energy consumption of the separation device for waste plastic pyrolysis oil and gas.

[0052] Preferably, after washing the solid particles entrained in the oil and gas, it further includes: The solid particles precipitate to the bottom of the column still 101 to form recycled oil; Withdraw the recycled oil from the bottom of the column still 101; Pressurize the recycled oil by the recycled oil transfer pump 23 and send it to the waste plastic pyrolysis equipment; Perform secondary pyrolysis on the recycled oil through the waste plastic pyrolysis equipment to form fuel.

[0053] Specifically, the solid particles precipitate to the bottom of the column still 101 and combine with the solvent oil with a relatively high average molecular weight (already in the oil phase in the column still 101) to form recycled oil. The recycled oil is withdrawn from the bottom of the column still 101, pressurized by the recycled oil transfer pump 23, and sent to the recycled oil storage tank; a column still liquid storage tank 24 is provided on the recycled oil transfer pump 23 to collect the column still 101 liquid withdrawn together with the recycled oil; the recycled oil in the recycled oil storage tank is sent to the waste plastic pyrolysis equipment, and the recycled oil is subjected to secondary pyrolysis through the waste plastic pyrolysis equipment to form fuel, and this fuel liquid can be used as the fuel of the lava furnace to further improve the waste utilization rate.

[0054] This embodiment provides experiments conducted through the separation device and method for waste plastic pyrolysis oil and gas: After putting the membrane-like PE waste plastic into the pyrolysis reactor, the obtained pyrolysis oil and gas are condensed to obtain an oil phase and non-condensable gas (the gas phase that never condenses). Samples of the oil phase and non-condensable gas are taken and analyzed respectively. The obtained analysis results are shown in Tables 1 and 2. Among them, the density before the fractionation point test is 0.775 g / cm 3 , and the density after the fractionation point test is 0.800 g / cm 3 : Table 1 Analysis data of the temperature and volume fractionation points of pyrolysis oil Table 2 Analysis Results of the Composition of Pyrolysis Non-Condensable Gas The whole components of the oil-gas mixture obtained by pyrolyzing the above-mentioned film-like PE waste plastics are transported to the fractionating tower of the present invention for separation. The pressure at the top of the tower is controlled to be -0.009 MPa(G). The gas phase at the top of the tower is condensed and then washed with alkali to obtain light solvent oil. The oil phase drawn from the side line is cooled and washed with alkali to obtain solvent oil. The analysis results of the two products are shown in Tables 3 and 4: Table 3 Analysis and Test Results of Light Solvent Oil Table 4 Analysis and Test Results of Solvent Oil The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A separation device for waste plastic pyrolysis oil and gas, characterized in that, It includes: A fractionating tower (1), which includes a reboiler (101) and a fractionating main body (102) arranged in sequence from bottom to top; A particle removal component, which is arranged inside the reboiler (101); Multiple trays (104), which are arranged inside the fractionating main body (102) in sequence from bottom to top, and side line draw-off ports (105) are arranged on each tray (104); A solvent oil extraction component (3), which includes a solvent oil extraction pipeline (301), and the side line draw-off ports (105) located on different trays (104) are selectively connected to the solvent oil extraction pipeline (301).

2. The separation device for waste plastic pyrolysis oil and gas according to claim 1, wherein: The particle removal component includes reboiler (101) liquid, chevron plates (103), a liquid distributor (106) and a reboiler liquid extraction component (2). The reboiler (101) liquid, chevron plates (103) and liquid distributor (106) are arranged inside the reboiler (101) in sequence from bottom to top, and the reboiler (101) liquid is located at the bottom of the reboiler (101), and the liquid distributor (106) is located at the top of the reboiler (101). The reboiler liquid extraction pipeline of the reboiler liquid extraction component (2) is connected to the draw-off port of the reboiler (101) liquid, and the reboiler liquid return pipeline (203) of the reboiler liquid extraction component (2) is connected to the liquid distributor (106) to enable the liquid distributor (106) to spray the reboiler (101) liquid onto the chevron plates (103).

3. The separation device for cracked oil and gas of waste plastics according to claim 1, wherein: The solvent oil extraction component (3) further includes a solvent oil extraction pump (302), a solvent oil cooler (303), a solvent oil caustic scrubber (304), a solvent oil temporary storage tank (305), a solvent oil transfer pump (306) and a solvent oil storage tank (307) connected in sequence through pipelines. The solvent oil extraction pump (302) is connected to the side line draw-off port (105) through the solvent oil extraction pipeline (301), and the solvent oil storage tank (307) is communicated with the first tanker (309) through a solvent oil output pump (308) to realize the transportation of the solvent oil on the tray (104) to the first tanker (309).

4. A method for separating pyrolysis oil and gas from waste plastics, characterized in that, It includes the following steps: Provide the separation device for waste plastic pyrolysis oil and gas as described in any one of claims 1 to 3; Input the gasoline mixture obtained from the waste plastic pyrolysis reaction into the inside of the reboiler (101); Carry out desuperheating on the rising oil and gas through the particle removal component, and wash the solid particles entrained in the oil and gas; Carry out mass transfer and heat transfer through the trays (104), wherein the average molecular weight of the solvent oil on the relatively upper tray (104) is smaller than that on the relatively lower tray (104); Selectively connect the side line draw-off ports (105) located on different trays (104) to the solvent oil extraction pipeline (301) to extract solvent oils with different average molecular weights.

5. The method for separating pyrolysis oil and gas from waste plastics according to claim 4, wherein The separation method further includes: Separate the light hydrocarbons and water at the top of the fractionating main body (102) from the top of the tower and enter the top condenser (4); Carry out condensation through the top condenser (4) to divide the light hydrocarbons and water into uncondensed gas phase and condensed liquid phase; Send the uncondensed gas phase to the subsequent treatment section; Send the condensed liquid phase to the light solvent oil condensate tank (5) to carry out phase separation to obtain light solvent oil and wastewater; Discharge the wastewater into the wastewater storage tank (20); Feed light solvent oil into the light solvent oil caustic scrubbing tank (6) and perform deacidification treatment; Feed the deacidified light solvent oil into the light solvent oil temporary storage tank (7); Pressurize the light solvent oil in the light solvent oil temporary storage tank (7) through the light solvent oil transfer pump (8) and transport it to the light solvent oil storage tank (9); Pressurize the light solvent oil in the light solvent oil storage tank (9) through the light solvent oil output pump (10) and output it to the second tanker (11).

6. The method for separating cracked oil and gas from waste plastics according to claim 5, characterized in that, The step of feeding the uncondensed gas phase into the subsequent treatment section specifically includes: Feed the uncondensed gas phase from the top condenser (4) into the liquid ring compressor (12) and compress it to form a gas phase and a liquid phase; Separate the gas phase and the liquid phase through the gas-liquid separator (13); Produce fuel from the gas phase; 19 Perform condensate stratification on the liquid phase to form an oil phase and wastewater; Send the oil phase to the light solvent oil condensate tank (5) and send the wastewater to the wastewater storage tank (20).

7. The method for separating pyrolysis oil and gas from waste plastics according to claim 6, characterized in that, The step of producing fuel from the gas phase specifically includes: Feed the gas phase into the non-condensable gas caustic scrubbing tower (14); Perform deacidification treatment through the non-condensable gas caustic scrubbing tower (14) to form fuel.

8. The method for separating pyrolysis oil and gas from waste plastics according to claim 6, characterized in that, The step of feeding the uncondensed gas phase into the subsequent treatment section further includes: Install a working fluid cooler (18) between the liquid ring compressor (12) and the gas-liquid separator (13); Cool the working fluid entering the liquid ring compressor (12) through the working fluid cooler (18).

9. The separation method of waste plastic pyrolysis oil and gas according to claim 4, characterized in that, The separation method further includes: Select two different trays (104), denoted as the upper tray (104) and the lower tray (104) respectively; Withdraw the hydrocarbon mixture from the lower tray (104); Pressurize the hydrocarbon mixture through the circulation pump (25) and send it to the circulation cooler (26); Cool the hydrocarbon mixture through the circulation cooler (26); Return the cooled hydrocarbon mixture to the upper tray (104).

10. The method for separating pyrolysis oil and gas from waste plastics according to claim 4, wherein, After washing the solid particles entrained in the washing oil gas, it further includes: The solid particles precipitate to the bottom of the column still (101) to form recycled oil; Withdraw the recycled oil from the bottom of the column still (101); Pressurize the recycled oil through the recycled oil transfer pump (23) and send it to the waste plastic pyrolysis equipment; Perform secondary pyrolysis on the recycled oil through the waste plastic pyrolysis equipment to form fuel.

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