A low naphthalene oil production system

Abstract

The application belongs to the technical field of positioning tooling, and discloses a low naphthalene washing oil production system, which comprises a filler tower and an inclined hole tower. The gas outlet of the filler tower is connected with the feed inlet of the inclined hole tower in communication, and the gas outlet of the inclined hole tower is connected with the gas inlet of the filler tower. The inclined hole tower is connected with a compressor set, and the compressor set can keep the inclined hole tower in a negative pressure state. By maintaining the inclined hole tower in a negative pressure environment, the boiling point of the material is significantly reduced. The inclined hole tower forms a turbulent flow through horizontal jet gas flow, accelerates gas-liquid contact, and makes the heat-sensitive material rapidly vaporize at low temperature, thereby avoiding decomposition or polymerization caused by high temperature. The inclined hole tower plate maintains a low liquid layer thickness under negative pressure, reduces the liquid residence time, further reduces the heating risk of the heat-sensitive material, and reduces the thermal decomposition rate of the inclined hole tower. By entering the positive pressure filler tower first and then entering the negative pressure inclined hole tower, the problem that the difference between the boiling points of naphthalene and washing oil is not fully utilized during production, resulting in high energy consumption, limited separation precision and low separation efficiency, is solved.

Description

Technical Field

[0001] This utility model belongs to the field of coal tar deep processing technology, specifically relating to a low-naphthalene washing oil production system. Background Technology

[0002] Currently, the denaphthalene removal process for wash oil in coal tar mostly employs a single pressure distillation column or a series multi-column separation technology. For example, Chinese invention patent application number CN201110199830.8 discloses a method for extracting low-naphthalene wash oil through three-column continuous distillation. Specifically, the method discloses that the raw material coking wash oil is sequentially passed through three continuous distillation columns, each with a side feed outlet, which can extract in one step a naphthalene fraction containing more than 80% naphthalene, a β-methylnaphthalene fraction containing more than 70% β-methylnaphthalene, an α-methylnaphthalene fraction containing more than 60% α-methylnaphthalene, medium wash oil, a acenaphthene fraction containing more than 60% acenaphthene, an oxygen fluorene fraction containing more than 55% oxygen fluorene, and a fluorene fraction containing more than 50% fluorene. This process is simple to operate, requires little equipment investment, and produces a variety of product fractions. It greatly facilitates the further processing of industrial-grade naphthalene, β-methylnaphthalene, α-methylnaphthalene, acenaphthene, fluorene, etc., and is particularly suitable for the deep processing of wash oil fractions in coal tar processing enterprises with a scale of 150,000 to 300,000 tons / year.

[0003] However, when using the above method for production, the difference in boiling points between naphthalene and wash oil is not fully utilized, resulting in high energy consumption and limited separation accuracy, thus leading to low separation efficiency. Summary of the Invention

[0004] Based on this, this application provides a low-naphthalene wash oil production system to solve the problem that the difference in boiling points between naphthalene and wash oil is not fully utilized during production, resulting in high energy consumption and limited separation accuracy, thus causing low separation efficiency.

[0005] The technical solution to the above-mentioned technical problems in this application is as follows: A low-naphthalene wash oil production system, comprising: The system includes a packed tower and an inclined hole tower, wherein the outlet of the packed tower is connected to the inlet of the inclined hole tower, and the outlet of the inclined hole tower is connected to the inlet of the packed tower; the inclined hole tower is connected to a compressor unit, which can keep the inclined hole tower under negative pressure.

[0006] Preferably, the packed tower is filled with inclined hole corrugated packing with a pore size of 10 mm to 15 mm and a porosity of not less than 85%.

[0007] Preferably, the surface of the oblique-hole corrugated packing is coated with a ceramic-polytetrafluoroethylene composite coating.

[0008] Preferably, the outlet of the inclined hole tower is connected to the inlet of the packed tower through a first heat exchanger, which is used for waste heat recovery.

[0009] Preferably, the outlet of the packed tower is connected to the inlet of the inclined hole tower through a second heat exchanger.

[0010] Preferably, the system further includes a byproduct recovery unit connected to the side stream of the inclined-hole tower for extracting β-methylnaphthalene and acenaphthene, and converting them into benzene intermediates through a hydrogenation refining process.

[0011] Preferably, the inclined hole tower is provided with a support grid and a tower plate, the support grid is connected to the inner wall of the inclined hole tower, and the tower plate is disposed on the support grid.

[0012] Preferably, a vibration monitoring element is provided on the support grid, and the vibration monitoring element is used to monitor the vibration frequency of the support grid.

[0013] Preferably, the bottom residual oil outlet of the inclined hole tower is connected to a wash oil regeneration system, and the regenerated wash oil is circulated to the benzene washing tower via a pressurized pump.

[0014] The technical solution adopted in this application can achieve the following beneficial effects: 1. By maintaining the inclined-hole column under negative pressure, the boiling point of the material is significantly reduced. The inclined-hole column creates turbulence through horizontal jetting airflow, accelerating gas-liquid contact and enabling heat-sensitive substances to vaporize rapidly at low temperatures, avoiding decomposition or polymerization caused by high temperatures.

[0015] 2. The inclined hole tray maintains a low liquid layer thickness under negative pressure, reducing the liquid residence time and further reducing the risk of heat-sensitive substances being heated, while also reducing the thermal decomposition rate of the inclined hole tray.

[0016] 3. By first introducing the naphthalene into a positive pressure packed tower and then into a negative pressure inclined hole tower, the problem of insufficient utilization of the boiling point difference between naphthalene and wash oil during production is solved, which leads to high energy consumption and limited separation accuracy, resulting in low separation efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall production system for the low-naphthalene washing oil of this application.

[0018] Figure 2 This is a schematic diagram showing the overall breakdown of the low-naphthalene wash oil production system of this application. Figure 1 .

[0019] In the diagram: packed tower 100, inclined hole corrugated packing 110, inclined hole tower 200, compressor unit 210, support grid 220, tower plate 230, first heat exchanger 240, second heat exchanger 250, wash oil regeneration system 300, by-product recovery unit 400. Detailed Implementation

[0020] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0021] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," "top," "bottom," "end," "top," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] Please see Figures 1 to 2 This application provides a low-naphthalene wash oil production system, including: a packed tower 100 and an inclined hole tower 200, wherein the outlet of the packed tower 100 is connected to the inlet of the inclined hole tower 200, and the outlet of the inclined hole tower 200 is connected to the inlet of the packed tower 100; the inclined hole tower 200 is connected to a compressor unit 210, which can keep the inclined hole tower 200 under negative pressure.

[0024] Specifically, the packed tower 100 is equipped with an air inlet, an air outlet, a feed inlet, and a discharge outlet. A liquid distributor is installed at the top of the packed tower 100, and another liquid distributor is installed in the middle of the packed tower 100. A packing support plate is installed inside the packed tower 100, and the packed tower 100 is filled with packing material (the specific structure of the packed tower 100 is not described in detail, as it is the same as existing patents and market products). The inclined hole tower 200 is a new type of distillation tower equipment, characterized by inclined channels. This design can increase the contact area between the gas and liquid phases, thereby improving mass transfer efficiency. A compressor unit 210 is installed inside the inclined hole tower 200, and a vacuum system is installed and connected to the compressor unit 210 via steam evacuation. The inclined hole tower 200 is under a negative pressure of -0.08MPa to -0.1MPa, while the packed tower 100 is under a positive pressure of 0.2MPa to 0.5MPa.

[0025] Furthermore, the packed tower 100 is under positive pressure. Liquid is uniformly sprayed from the top of the packed tower 100 onto the surface of the packing layer through a liquid distributor. Under the action of gravity, a liquid film forms on the surface of the packing and flows downward. Gas flows counter-currently from the bottom of the packed tower 100 through the gaps in the packing layer and comes into full contact with the liquid film. Molecular diffusion and energy exchange occur between the gas and liquid phases on the surface of the packing. The component concentration and temperature change continuously along the height of the tower, forming a differential contact process. Then, the gas enters the feed inlet of the inclined hole tower 200 from the outlet of the packed tower 100. The inclined hole tower 200 is under negative pressure. Inside the inclined hole tower 200, the gas is sprayed out at an angle from the inclined holes, pushing the liquid to flow along the surface of the tray 230, forming a low and uniform liquid layer. The flow direction of the liquid on the tray 230 inside the inclined hole tower 200 is perpendicular to the jet direction of the inclined holes. The boiling point difference is reduced by operating under negative pressure.

[0026] The technical solution of the low-naphthalene wash oil production system adopted in this application can achieve the following beneficial effects: 1. By maintaining the inclined-hole tower 200 under negative pressure, the boiling point of the material is significantly reduced. The inclined-hole tower 200 creates turbulence through horizontal jet airflow, accelerating gas-liquid contact and enabling heat-sensitive substances to vaporize rapidly at low temperatures, avoiding polymerization or decomposition caused by high temperatures.

[0027] 2. The inclined hole tower 200 plate maintains a low liquid layer thickness under negative pressure, reducing the liquid residence time, further reducing the risk of heat-sensitive materials being heated, and at the same time reducing the thermal decomposition rate of the inclined hole tower 200.

[0028] 3. By first introducing the naphthalene into the positive pressure packed tower 100 and then into the negative pressure inclined hole tower 200, the problem of insufficient utilization of the boiling point difference between naphthalene and wash oil during production is solved, which leads to high energy consumption and limited separation accuracy, resulting in low separation efficiency.

[0029] Based on the above scheme, the packed tower 100 is filled with oblique-hole corrugated packing 110, with a pore size of 10mm to 15mm and a porosity of not less than 85%. The oblique-hole design with a pore size of 10mm to 15mm, combined with high porosity (≥85%), ensures sufficient specific surface area while forming three-dimensional staggered flow channels, promoting turbulent mixing of the gas and liquid phases. For example, the corrugated structure disperses the liquid into a uniform liquid film, and the gas flows at high speed between the crests and troughs, resulting in a significant improvement in mass transfer efficiency compared to traditional packing. The high porosity significantly reduces fluid resistance, making it suitable for vacuum or high-flow-rate conditions. The horizontal jet airflow generated by the oblique-hole structure can scour the packing surface, effectively preventing tar or polymer deposition.

[0030] The design of the packed tower 100 filled with inclined hole corrugated packing 110 (pore size 10mm to 15mm, porosity ≥85%) can significantly improve separation efficiency and operational stability through the synergistic optimization of structural parameters and mass transfer performance.

[0031] In a preferred embodiment of this application, the surface of the oblique-hole corrugated packing 110 is coated with a ceramic-polytetrafluoroethylene composite coating.

[0032] The molecular structure of polytetrafluoroethylene (PTFE) results in extremely low surface energy (approximately 18-22 mN / m), giving it hydrophobic and oleophobic properties. Liquids (such as water and oil) can have contact angles exceeding 110° on its surface, exhibiting a "lotus effect," making it difficult for contaminants to adhere; they are easily washed away by water flow. The nano-ceramic particles in the composite coating generate electron-hole pairs under light, reacting with water molecules in the air to produce hydroxyl radicals, which can decompose organic matter and microorganisms. The ceramic particles (10-50 nm in diameter) embedded in the PTFE matrix form a rough micro-nano composite structure, further reducing surface energy and enhancing self-cleaning capabilities. The chemical inertness of PTFE combined with the density of ceramics resists corrosion from acids, alkalis, and organic solvents. The antibacterial properties of silver or copper nanoparticles inhibit microbial growth. The matching thermal expansion coefficients of ceramic and PTFE reduce the risk of coating cracking and increase its resistance to temperature shocks. Ceramic-polytetrafluoroethylene composite coatings (such as the nano-ceramic-polytetrafluoroethylene coating for centrifugal pumps and its preparation method disclosed in CN104650667B, which forms a ceramic-polytetrafluoroethylene composite coating by brushing) achieve comprehensive improvement in antifouling, corrosion resistance and mechanical properties through the synergistic effect of low surface energy, photocatalysis and micro-nano structure.

[0033] In another preferred embodiment of this application, the outlet of the inclined hole tower 200 is connected to the inlet of the packed tower 100 via a first heat exchanger 240, the first heat exchanger 240 being used for waste heat recovery. The outlet of the packed tower 100 is connected to the inlet of the inclined hole tower 200 via a second heat exchanger 250.

[0034] Both the first heat exchanger 240 and the second heat exchanger 250 utilize, but are not limited to, eddy current heat film heat exchangers, which have high heat transfer coefficients and low energy consumption. Through the synergistic effects of heat conduction, convection, and radiation, combined with structural optimization (such as oblique holes and eddy current design), the first heat exchanger 240 and the second heat exchanger 250 achieve efficient heat transfer, improve corrosion resistance, and reduce energy consumption. Simultaneously, by passing the gas from the packed tower 100 and the oblique hole tower 200 through the first heat exchanger 240 and the second heat exchanger 250 for temperature adjustment and mutual circulation, energy consumption is reduced, minimizing heat waste.

[0035] In another embodiment of this application, a byproduct recovery unit 400 is also included. The byproduct recovery unit 400 is connected to the side line of the inclined hole tower 200 and is used to extract β-methylnaphthalene and acenaphthene and convert them into benzene intermediates through a hydrogenation refining process.

[0036] β-methylnaphthalene and acenaphthene are converted into benzene intermediates by catalytic hydrogenation (such as Ni-Mo / Al2O3 catalyst). β-methylnaphthalene is hydrogenated to tetrahydronaphthalene or decahydronaphthalene; acenaphthene is hydrogenated to tetrahydroacenaphthene. The reaction conditions are typically 200℃ to 300℃ and 3MPa to 5MPa. The hydrogenation process simultaneously removes impurities such as sulfur and nitrogen (e.g., quinoline compounds). Combined with subsequent molecular distillation (vacuum 6MPa to 10MPa), the purity of benzene intermediates is improved. The byproduct recovery unit 400 utilizes existing technology and is a common chemical process; its structure will not be elaborated upon here. Side-stream extraction increases the recovery rate of β-methylnaphthalene and acenaphthene. Hydrogenation refining converts low-value-added byproducts into high-value benzene intermediates. The hydrogenation process replaces strong acid / base treatment, reducing sulfur-containing wastewater discharge. Simultaneously, the synergy between side-stream extraction from the inclined-hole tower 200 and hydrogenation refining achieves a closed loop of "efficient separation - targeted conversion - high-value utilization," enhancing resource value while reducing environmental impact.

[0037] Based on the above scheme, the inclined hole tower 200 is provided with a support grid 220 and a tower plate 230. The support grid 220 is connected to the inner wall of the inclined hole tower 200, and the tower plate 230 is disposed on the support grid 220.

[0038] The support grid 220 is made of metal or corrosion-resistant alloy (such as 316L stainless steel or titanium alloy) to form a mesh frame, which is fixed to the inner wall of the tower by welding or bolting. The grid spacing is usually 50mm to 100mm, which can withstand the load of the tray 230 while allowing the gas and liquid phases to pass freely. It provides a mounting base for the tray 230 to ensure that the levelness error of the tray 230 is less than 0.5mm / m, while dispersing the fluid impact force and reducing local pressure drop. The tray 230 has rectangular oblique holes (size: length 20mm to 35mm, width 10mm to 25mm), with the opening direction perpendicular to the liquid flow, and adjacent rows of holes are arranged in opposite directions and staggered. Fan-shaped oblique holes (opening angle 38°) are added to the edge area to enhance gas-liquid contact near the tower wall. Some trays 230 integrate guide float valve holes (such as patent CN31332756U). The float valve can automatically adjust the opening degree according to the gas flow, solving the problem of low gas flow leakage in the oblique hole tower 200, and improving operational flexibility.

[0039] Furthermore, when the gas passes through the oblique holes, the sudden change in direction generates a transverse vortex, breaking the laminar boundary layer and increasing the turbulence intensity; the airflow from adjacent reverse oblique holes counteracts each other, causing the droplets to break up and become finer, thereby increasing the mass transfer area; the gas is ejected parallel along the oblique holes, forming a tangential scouring force on the surface of the tray 230, reducing the deposition of inorganic salts (such as CaCO3), thereby improving the scale prevention capability.

[0040] Furthermore, a vibration monitoring device is installed on the support grid 220 to monitor the vibration frequency of the support grid 220. The vibration monitoring device may employ, but is not limited to, piezoelectric, eddy current, inductive, or capacitive vibration monitors. By observing the monitoring parameters of the vibration monitoring device, operators can adjust the vibration frequency of the support grid 220 and the tower plate 230 to determine the blockage rate, making the judgment simpler and more convenient. Simultaneously, based on the monitoring parameters, the operator can stop the machine, replace the support grid 220, or perform maintenance, further simplifying the operation.

[0041] In another embodiment of this application, the bottom residual oil outlet of the inclined hole tower 200 is connected to a wash oil regeneration system 300, and the regenerated wash oil is circulated to the benzene washing tower via a pressurized pump.

[0042] The bottom of the inclined hole tower 200 is equipped with a residual oil outlet to discharge residual oil containing high molecular polymers, impurities and incompletely separated components; The wash oil regeneration system 300 includes a regenerator, a residual oil tank, a filtration device (such as a multi-stage filtration layer), and a pressure pump; these are connected in sequence (using existing technology, the specific structure is not described in detail). The regenerator is typically equipped with a heater (such as a tubular furnace or reboiler) and a separation structure (such as an inclined hole sieve plate or a vacuum distillation device); the regenerator uses an inclined hole sieve plate or vacuum distillation technology to separate light and heavy components in the residual oil and remove impurities such as gums and asphaltenes; the filtration device uses a three-stage filtration layer (such as a metal filter screen and an activated carbon adsorption layer) to remove particulate matter and ensure the cleanliness of the regenerated wash oil; the pressure pump provides circulation power and optimizes the reuse ratio of the regenerated wash oil through flow control.

[0043] The regenerated wash oil is pumped to the top of the benzene washing tower via a pressurized pump, forming a closed-loop circulation system. This replaces the fresh wash oil, reducing raw material consumption. The oil vapor (such as benzene vapor) at the top of the regenerator is returned to the benzene removal tower as a heat source, reducing external steam demand. The integrated design of the inclined hole tower 200 and the wash oil regeneration system 300 achieves efficient resource utilization and environmental protection and energy saving through a closed-loop process of "separation-regeneration-circulation," while also playing a role in low consumption, high recovery rate, and green production.

[0044] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A low-naphthalene wash oil production system, characterized in that, include: The system includes a packed tower and an inclined hole tower, wherein the outlet of the packed tower is connected to the inlet of the inclined hole tower, and the outlet of the inclined hole tower is connected to the inlet of the packed tower; the inclined hole tower is connected to a compressor unit, which can keep the inclined hole tower under negative pressure.

2. The low-naphthalene wash oil production system as described in claim 1, characterized in that, The packed tower is filled with inclined hole corrugated packing with a pore size of 10 mm to 15 mm and a porosity of not less than 85%.

3. The low-naphthalene wash oil production system as described in claim 2, characterized in that, The surface of the oblique-hole corrugated packing is coated with a ceramic-polytetrafluoroethylene composite coating.

4. The low-naphthalene wash oil production system as described in claim 1, characterized in that, The outlet of the inclined hole tower is connected to the inlet of the packed tower through a first heat exchanger, which is used for waste heat recovery.

5. The low-naphthalene wash oil production system as described in claim 1, characterized in that, The outlet of the packed tower is connected to the inlet of the inclined hole tower through a second heat exchanger.

6. The low-naphthalene wash oil production system as described in claim 1, characterized in that, It also includes a byproduct recovery unit, which is connected to the side stream of the inclined-hole tower to extract β-methylnaphthalene and acenaphthene and convert them into benzene intermediates through a hydrogenation refining process.

7. The low-naphthalene wash oil production system as described in claim 1, characterized in that, The inclined hole tower is equipped with a support grid and a tower plate. The support grid is connected to the inner wall of the inclined hole tower, and the tower plate is disposed on the support grid.

8. The low-naphthalene wash oil production system as described in claim 7, characterized in that, A vibration monitoring device is installed on the support grid, and the vibration monitoring device is used to monitor the vibration frequency of the support grid.

9. The low-naphthalene wash oil production system as described in claim 1, characterized in that, The bottom residual oil outlet of the inclined hole tower is connected to a wash oil regeneration system, and the regenerated wash oil is circulated to the benzene washing tower via a pressurized pump.

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