Coal to olefin production water deep treatment coupling photocatalytic hydrogen production device and method

Abstract

The application provides a coal-to-olefin production water deep treatment coupled photocatalytic hydrogen production device and method, and relates to the field of industrial wastewater treatment. The method removes volatile substances from production water through stripping, and purifies water to preheat catalyst slurry. After preheating, the catalyst is mixed with a refluxed thick slurry, and is sent into a vertical multi-tube cyclone separator with an embedded photocatalytic module. Under the cooperation of cyclone shearing, light radiation and negative pressure, photocatalytic degradation and hydrogen production are simultaneously performed. After separation, the liquid phase is post-treated, and the catalyst thick slurry is circulated. The application realizes efficient mineralization of wastewater and in-situ hydrogen production, solves the problems of heat loss, low light quantum efficiency and catalyst deactivation, and cooperatively treats wastewater and produces hydrogen.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater treatment, and more particularly to a device and method for deep treatment of coal-to-olefins production water coupled with photocatalytic hydrogen production. Background Technology

[0002] Coal chemical industry is the process of using coal as raw material and chemically processing it into gaseous, liquid, and solid energy sources and chemicals. Among them, coal-to-olefins technology, as the core route of new coal chemical industry, synthesizes methanol through coal gasification, and then produces low-carbon olefins such as ethylene and propylene through methanol-to-olefins reaction, effectively alleviating dependence on petroleum resources.

[0003] Coal-to-olefins projects consume enormous amounts of water, with water consumption reaching 27-30 tons per ton of olefins produced. The wastewater generated by its quench tower and washing system is characterized by high temperature, high chemical oxygen demand (COD), high suspended solids, and complex composition, making it difficult to treat. Currently, the industry's conventional treatment method for this type of wastewater often involves using a stripping tower to remove light components, then cooling the high-temperature purified wastewater through a waste heat exchanger before sending it to the final biochemical treatment unit. However, this approach has significant drawbacks: First, energy utilization efficiency is low; the high-grade heat energy carried by the wastewater is devalued only through physical heat exchange and fails to be converted into high-value chemical energy. Second, resource loss is severe; trace amounts of organic matter in the wastewater create COD load pressure, and fine catalyst powder is difficult to recover efficiently through gravity sedimentation, leading to the continuous loss of valuable catalysts. Third, system operational stability is poor; solid particles easily accumulate in equipment dead zones, restricting the long-term operation of the unit.

[0004] In coal-to-olefins and similar processes, the treatment of waste alkaline solutions and wastewater is a crucial step. Patent CN117985906B proposes a hydrogen production, storage, and cogeneration system for a wastewater treatment plant. By integrating anaerobic digestion, biogas reforming for hydrogen production, and waste heat recovery, it achieves carbon reduction and energy regeneration; however, the system is complex and highly dependent on biogas purity. Patent CN117142681A describes a desulfurization biochemical treatment process for coal-to-olefins waste alkaline solutions, employing multi-stage oxidation and biological pretreatment to reduce sulfide content; however, the process chain is long and its adaptability to high-salinity wastewater is limited. Patent CN112546865B developed a system for reusing purified water from methanol-to-olefins processes, utilizing membrane filtration technology to remove suspended solids and oils, achieving water recycling; however, membrane fouling issues are not completely resolved. Patent CN109896692B discloses a coupled coal-to-olefins and wastewater treatment process, using the co-treatment of waste residue and waste alkaline solutions to treat waste with waste; however, the resource utilization of byproducts is insufficient. Patent CN205933522U provides a treatment device for alkaline wastewater from coal-to-olefins production, which combines oil removal, evaporation, and organic matter decomposition units, simplifying the process, but energy consumption control remains a challenge. Authorized patent CN113292191B designs a device for the catalytic thermal cracking of residual oil and the resource utilization of alkaline wastewater from coal-to-olefins production. It achieves mixed salt recovery by separating sodium thiosulfate and sodium hydroxide through causticization and salting out, but solvent recovery costs are high.

[0005] Catalyst efficiency and wastewater treatment in the methanol-to-olefins (MTO) process directly affect economic viability. Patent CN111423302B proposes a method and apparatus for MTO, employing a fully regenerated catalyst to react with byproducts to improve olefin yield; however, the catalyst pretreatment requirements are stringent. Patent CN218846969U relates to a methanol-steam heat exchange system in a coal-to-olefins plant, improving energy efficiency through multi-stage heat exchange; however, the waste heat utilization scenarios are limited.

[0006] Gas-liquid separation efficiency is crucial to the stability of chemical processes. Authorized patent CN102489101B discloses a gas-liquid separator that uses a combination of cyclone separation and a defoaming screen to improve separation accuracy; however, the equipment is large and suitable for high-pressure conditions. Publicated patent CN117504773A proposes a photocatalytic hydrogen production device that produces hydrogen by decomposing water through ultraviolet light irradiation and catalyst action. It is suitable for small-scale experiments, but for large-scale applications, photon utilization is low and the reaction rate is temperature-dependent.

[0007] Existing photocatalytic hydrogen production technologies mostly rely on a single light field, resulting in low photon utilization and failure to utilize waste heat resources. Catalysts are mostly added only once and are not adapted to the high-salt characteristics of wastewater, making them prone to agglomeration, deactivation, and severe loss, which makes it difficult to meet the requirements of long-term industrial operation. Summary of the Invention

[0008] In view of this, the purpose of this invention is to overcome the shortcomings of the prior art and provide a device and method for deep treatment of coal-to-olefins production water coupled with photocatalytic hydrogen production. Through the cascade utilization of high-temperature wastewater waste heat, the combination of multi-physical field synergistic photocatalytic reaction, the swirling enhanced mass transfer and the dynamic closed-loop circulation regeneration mechanism of the catalyst, the invention achieves efficient mineralization of recalcitrant organic matter in wastewater and in-situ production of green hydrogen. At the same time, it solves the problems of large heat loss, low photon efficiency, easy deactivation and loss of catalyst and poor system operation stability in coal-to-olefins wastewater treatment, and realizes the synergy of wastewater treatment, hydrogen resource enhancement and multi-resource recovery.

[0009] This invention provides the following technical solution: In a first aspect, embodiments of this application provide a coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production apparatus for the method described in the above embodiments, comprising: The stripping tower is equipped with a purified water outlet; The buffer tank is connected to the purified water outlet of the stripping tower via an insulated pipeline. The buffer tank is equipped with a fresh catalyst inlet and a reflux catalyst inlet, and is equipped with a stirrer and a concentration monitoring sensor inside the tank. A vertical multi-tube hydrocyclone separator is provided. The outlet of the buffer tank is connected to the inlet of the vertical multi-tube hydrocyclone separator via a pressurized pump and a pressurized delivery pipeline. The vertical multi-tube hydrocyclone separator includes a hydrocyclone tank and multiple first hydrocyclone tubes arranged in parallel within the hydrocyclone tank. The hydrocyclone tank is divided into a first liquid inlet chamber, a first overflow chamber, a first liquid collection chamber, and a first underflow chamber from top to bottom. The liquid inlet of each first hydrocyclone tube is connected to the first liquid collection chamber, the overflow port of each first hydrocyclone tube is connected to the first overflow chamber, and the underflow port of each first hydrocyclone tube is connected to the first underflow chamber. The vertical multi-tube hydrocyclone separator has a gas outlet at the top and a first liquid-solid mixed phase outlet at the bottom. The inlet of the vertical multi-tube hydrocyclone separator is connected to the first liquid inlet chamber, the gas outlet of the vertical multi-tube hydrocyclone separator is connected to the first overflow chamber, the first liquid-solid mixed phase outlet of the vertical multi-tube hydrocyclone separator is connected to the first underflow chamber, and the first liquid inlet chamber is connected to the first liquid collection chamber. A photocatalytic module, comprising an optical fiber column and a light source optically connected to the optical fiber column, wherein the end of the optical fiber column away from the light source is located within the first liquid collection cavity; A liquid-solid hydrocyclone includes a separation tank and a plurality of second hydrocyclones arranged in parallel within the separation tank. The separation tank is divided from top to bottom into a second overflow chamber, a second liquid collection chamber, and a second underflow chamber. The second liquid collection chamber is connected to the outlet of the first liquid-solid mixed phase. The overflow port of the second hydrocyclone is connected to the second overflow chamber, the liquid inlet of the second hydrocyclone is connected to the second liquid collection chamber, and the underflow port of the second hydrocyclone is connected to the second underflow chamber. The separation tank is provided with a clear liquid outlet and a second liquid-solid mixed phase outlet. The clear liquid outlet is connected to the second overflow chamber, and the second liquid-solid mixed phase outlet is connected to the reflux catalyst inlet of the buffer tank. The gas outlet is connected to a hydrogen purification unit.

[0010] In some embodiments of the first aspect, the first inlet chamber is connected to the first collection chamber via a plurality of transfer pipes; each of the transfer pipes is spaced apart along the circumference of the cyclone tank.

[0011] In some embodiments of the first aspect, the stripping tower, buffer tank, vertical multi-tube hydrocyclone and liquid-solid hydrocyclone are connected in series via insulated pipelines, so that the purified water exchanges heat with the fresh catalyst slurry in the insulated pipelines.

[0012] In some embodiments of the first aspect, the surface of the optical fiber pillar is sequentially provided with a wear-resistant ceramic substrate, a photocatalytic catalyst layer, and... An erosion-resistant protective layer; wherein the thickness of the wear-resistant ceramic substrate is 0.2 mm to 0.4 mm, and the thickness of the photocatalytic catalyst layer is 0.05 mm to 0.1 mm. The thickness of the erosion-resistant protective layer is 0.02 mm to 0.05 mm.

[0013] In some embodiments of the first aspect, the light source is an artificial light source or sunlight, the optical fiber post is arranged at the center of the first liquid collection cavity, and the depth of the optical fiber post extending into the first liquid collection cavity is 60% to 90% of the height of the first cyclone tube.

[0014] In some embodiments of the first aspect, the photocatalyst layer is A piezoelectric-photonic bifunctional catalyst layer composed of lead zirconate titanate in a mass ratio of (6.5-7.5):(3.5-2.5).

[0015] In some embodiments of the first aspect, the second liquid-solid mixed phase outlet of the liquid-solid cyclone separator is provided with a pulse backflushing mechanism; the second liquid-solid mixed phase outlet of the liquid-solid cyclone separator is connected to the reflux catalyst inlet of the buffer tank and the catalyst regeneration system respectively via a diversion pipe, and a control valve is provided on the diversion pipe.

[0016] In some embodiments of the first aspect, the stripping tower is a packed tower, the packed tower is filled with stainless steel ring saddle packing, the bottom of the packed tower is equipped with a steam coil heating system, and the top of the packed tower is equipped with an exhaust port, which is connected to the feed end of the waste oil recycling system through a pipeline.

[0017] In some embodiments of the first aspect, the buffer tank is equipped with a turbine agitator and an online catalyst concentration monitoring sensor. The online catalyst concentration monitoring sensor and the fresh catalyst dosing pump are electrically connected to a controller. The controller controls the fresh catalyst dosing pump to adjust the amount of fresh catalyst added based on the real-time concentration signal sent by the online catalyst concentration monitoring sensor.

[0018] Secondly, embodiments of this application provide a method for deep water treatment coupled with photocatalytic hydrogen production in coal-to-olefins production, comprising the following steps: S100: Water from coal-to-olefins production is fed into a stripping tower and heated and / or depressurized at 80°C to 120°C to remove light hydrocarbons and volatile pollutants; the resulting purified water is transported through an insulated pipeline and exchanged with a fresh catalyst slurry to preheat the fresh catalyst slurry to 60°C to 80°C. S200: The preheated fresh catalyst slurry is mixed with the reflux catalyst concentrate from the liquid-solid hydrocyclone separator in a buffer tank. The catalyst concentration in the mixture is adjusted to 50 mg / L to 200 mg / L. The mixed fluid is pressurized and sent to a vertical multi-tube hydrocyclone separator. The vertical multi-tube hydrocyclone separator is equipped with a photocatalytic module. Through the synergistic effect of the cyclone shear field, the light radiation field and the central negative pressure field, photocatalytic degradation of organic pollutants and hydrogen production are carried out simultaneously with gas-liquid-solid three-phase separation. The hydrogen-rich gas obtained after separation is purified and then output. S300: The liquid-solid mixture after hydrocyclone separation enters the liquid-solid hydrocyclone separator. The separated liquid phase is sent to the post-processing unit. The concentrated slurry containing the catalyst is returned to the buffer tank for recycling. A portion of the deactivated catalyst is periodically discharged to maintain the catalytic activity of the system.

[0019] In some embodiments of the second aspect, the vertical multi-tube cyclone separator operates at a flow rate of 4.0 m / s to 5.5 m / s, the photocatalytic module has a light intensity density of 50 mW / cm² to 100 mW / cm², and the separator has a central negative pressure of -0.05 MPa to -0.10 MPa.

[0020] The embodiments of the present invention have the following advantages: This invention fully utilizes the high-temperature characteristics of water produced in coal-to-olefins production. Purified water, treated at 80°C to 120°C in the stripping tower, is transported via insulated pipelines and preheated to 60°C to 80°C by exchanging heat with fresh catalyst slurry. This directly utilizes previously wasteful low-grade heat energy to raise the starting temperature of the photocatalytic hydrogen production reaction, converting heat energy into high-value chemical energy (hydrogen). This achieves a transformation from degraded to upgraded energy utilization, significantly improving the overall system's energy efficiency.

[0021] This invention integrates a photocatalytic module within a vertical multi-tube cyclone separator. Through the synergistic effect of the cyclone shear field, the light radiation field, and the central negative pressure field, it simultaneously performs photocatalytic degradation of organic pollutants and in-situ hydrogen production while achieving efficient gas-liquid-solid three-phase separation. The intense turbulence generated by the cyclone shear field enhances the solid-liquid mass transfer process between the catalyst and organic pollutants in the wastewater, while the central negative pressure field enables rapid separation and extraction of hydrogen-rich gas, effectively suppressing the recombination of photogenerated electrons and holes. Compared with existing photocatalytic technologies using a single light field, this invention significantly improves photon utilization and reaction rate through multi-physics field coupling, achieving efficient mineralization of recalcitrant organic matter in wastewater and in-situ production of green hydrogen.

[0022] This invention utilizes a liquid-solid cyclone separator to recycle the catalyst-rich concentrated slurry back to a buffer tank, while periodically discharging a portion of deactivated catalyst to maintain system catalytic activity. This dynamic closed-loop management mechanism effectively solves the industry problems of efficient recovery of fine catalyst powder via gravity settling and continuous loss of valuable catalysts in existing technologies. The recycling of catalyst within the system not only significantly reduces catalyst usage costs but, more importantly, avoids reaction efficiency degradation due to catalyst loss, ensuring the stability and economy of the equipment during long-term industrial operation.

[0023] This invention integrates multiple unit operations, including stripping pretreatment, waste heat recovery, photocatalytic reaction, gas-liquid separation, and catalyst recycling, into a single system. Through highly integrated process design, it achieves in-situ production of green hydrogen and multi-stage catalyst recovery while deeply treating high-temperature, high-COD, and high-suspended-solids wastewater from coal-to-olefins production, resulting in significant environmental and economic benefits.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This paper presents a schematic diagram of the structure of the coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device of this application; Figure 2 This paper shows a schematic diagram of the vertical multi-tube cyclone separator according to one view. Figure 3 A schematic diagram of the photocatalytic module in this application is shown; Figure 4 A schematic diagram of the liquid-solid cyclone separator in this application is shown; Figure 5 A schematic flow diagram of the coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production method of this application is shown.

[0027] Explanation of key component symbols: 1-Stripping tower; 2-Buffer tank; 3-Vertical multi-tube hydrocyclone separator; 4-Liquid-solid hydrocyclone separator; 5-Photocatalytic module; 31-Swirl tank; 32-First liquid inlet chamber; 33-First overflow chamber; 34-First liquid collection chamber; 35-First underflow chamber; 36-Transfer pipe; 37-First swirl tube; 38-First liquid-solid mixed phase outlet; 39-Gas outlet; 41-Separation tank; 42-Second overflow chamber; 43-Second collection chamber; 44-Second underflow chamber; 45-Clear liquid outlet; 46-Second liquid-solid mixed phase outlet; 51-Fiber optic column; 52-Light source; 53-Concentrating device. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0029] It should be noted that when an element is said to be "fixed" to another element, it can be directly on the other element or there may be an intervening element. When an element is said to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element. Conversely, when an element is said to be "directly" on another element, there is no intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0030] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] 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 template description is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] like Figures 1 to 5 As shown, in order to solve the above-mentioned technical problems, this application provides a method for deep water treatment coupled with photocatalytic hydrogen production in coal-to-olefins production, including the following steps: S100: Water from coal-to-olefins production is fed into stripping tower 1 and heated and / or depressurized at 80°C to 120°C to remove light hydrocarbons and volatile pollutants; the resulting purified water is transported through an insulated pipeline and exchanged with fresh catalyst slurry to preheat the fresh catalyst slurry to 60°C to 80°C.

[0034] In these embodiments, the production wastewater discharged from the quench tower of the coal-to-olefins unit is pumped into stripping tower 1 (operating pressure 0.05 MPaG, bottom temperature 110°C) for removal. Light hydrocarbons and volatile organic compounds. After stripping, the purified water temperature is maintained at 105°C and transported to the catalyst preheating heat exchanger through insulated stainless steel pipelines (covered with an aluminum silicate fiber insulation layer). Here, the purified water undergoes indirect heat exchange with the freshly prepared composite photocatalyst slurry, preheating the catalyst slurry from room temperature to 70°C while the purified water is cooled to 65°C before entering the subsequent treatment unit.

[0035] S200: The preheated fresh catalyst slurry is mixed with the reflux catalyst concentrate from the liquid-solid hydrocyclone separator in the buffer tank 2. The catalyst concentration in the mixture is adjusted to 50 mg / L to 200 mg / L. The mixed fluid is pressurized and sent to the vertical multi-tube hydrocyclone separator 3. The vertical multi-tube hydrocyclone separator 3 is equipped with a photocatalytic module 5. Through the synergistic effect of the cyclone shear field, the light radiation field and the central negative pressure field, the organic pollutants are photocatalytically degraded and hydrogen is produced during the gas-liquid-solid three-phase separation. The hydrogen-rich gas obtained by separation is purified and then output.

[0036] The preheated catalyst slurry is mixed with the reflux concentrate from the liquid-solid hydrocyclone separator in buffer tank 2. The catalyst concentration in the mixture is adjusted to 120 mg / L by a combination of an online turbidity meter and a metering pump. The mixed fluid is pressurized to 0.8 MPa by a high-pressure diaphragm pump and sent to a vertical multi-tube hydrocyclone separator 3. This separator consists of six parallel first hydrocyclone tubes 37, each with a hollow quartz fiber column 51 at its center and an internal ultraviolet LED light source 52, forming a photocatalytic module 5.

[0037] Inside the first cyclone tube 37, the fluid is driven by the tangential inlet to form a high-speed rotating flow field, generating strong centrifugal force and a central negative pressure zone. Simultaneously, ultraviolet light radiates radially along the fiber column 51, activating catalyst particles near the tube wall. The central negative pressure zone promotes the precipitation and aggregation of dissolved hydrogen into bubbles. Thus, under the synergistic effect of the cyclone shear field, the light radiation field, and the central negative pressure field, recalcitrant organic matter (such as benzene compounds, aldehydes, and ketones) in the wastewater is efficiently mineralized by ·OH free radicals, and water reduction reactions occur simultaneously to generate… Hydrogen-rich gas is discharged from the top of the first cyclone tube 37, and after condensation, dehumidification, and palladium membrane purification, high-purity hydrogen is obtained.

[0038] S300: The liquid-solid mixture after hydrocyclone separation enters the liquid-solid hydrocyclone separator. The separated liquid phase is sent to the post-processing unit. The concentrated slurry containing the catalyst is returned to the buffer tank 2 for recycling. A portion of the deactivated catalyst is periodically discharged to maintain the catalytic activity of the system.

[0039] The liquid-solid mixture after hydrocyclone separation flows out from the bottom of the first hydrocyclone tube 37 and enters a horizontal screw centrifuge (liquid-solid hydrocyclone separator), where solid-liquid separation is achieved at a set speed. The separated clarified liquid is sent to the subsequent biochemical treatment unit for further discharge or reuse after meeting standards. Most of the concentrated slurry is recycled back to the buffer tank 2 for reuse, while the remainder is discharged into the regeneration tank as deactivated catalyst. After ultrasonic cleaning and low-temperature calcination to restore its activity, it is re-formulated into the slurry replenishment system to maintain the overall catalytic activity stability.

[0040] In some embodiments, the vertical multi-tube cyclone separator 3 operates at a flow rate of 4.0 m / s to 5.5 m / s, the photocatalytic module 5 has a light intensity density of 50 mW / cm² to 100 mW / cm², and the separator center negative pressure is -0.05 MPa to -0.10 MPa.

[0041] In these embodiments, the operating parameters of the vertical multi-tube cyclone separator 3 are systematically controlled to achieve an optimal balance between photocatalytic efficiency, three-phase separation effect and energy consumption.

[0042] By adjusting the outlet pressure of the high-pressure diaphragm pump, the linear velocity of the mixed fluid entering each first cyclone tube 37 is maintained within the range of 4.0 m / s to 5.5 m / s. When the flow velocity is below 4.0 m / s, the cyclone shear force is insufficient, the solid particles settle inadequately, leading to increased catalyst entrainment loss. When the flow velocity exceeds 5.5 m / s, the residence time is too short, the photocatalytic reaction is incomplete, and the equipment vibration intensifies.

[0043] The photocatalytic module 5 incorporates a high-power ultraviolet LED array, and a constant current drive circuit precisely controls the light intensity density between 50 mW / cm² and 100 mW / cm². Below 50 mW / cm², the generation rate of photogenerated electron-hole pairs is limited, resulting in insufficient yield; above 100 mW / cm², local overheating occurs, accelerating the formation of lattice defects in the catalyst. 75 mW / cm² is preferred, as this condition yields the highest hydrogen production per unit of energy consumption.

[0044] The gas outlet 39 at the top of the first cyclone tube 37 is connected to a vacuum ejector, and the central negative pressure is stabilized between -0.05 MPa and -0.10 MPa by adjusting the back pressure valve. This negative pressure zone not only promotes... Bubbles rapidly desorb from the liquid phase, preventing gas film from covering the catalyst surface and enhancing turbulent mixing in the swirling core region.

[0045] In some embodiments, this application also provides a coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device for the method described in the above embodiments, comprising: Stripping tower 1 is equipped with a purified water outlet; Buffer tank 2 is connected to the purified water outlet of stripping tower 1 through an insulated pipeline. Buffer tank 2 is provided with a fresh catalyst inlet and a reflux catalyst inlet. A stirrer and a concentration monitoring sensor are provided inside the tank. A vertical multi-tube hydrocyclone separator 3 is provided. The outlet of the buffer tank 2 is connected to the inlet of the vertical multi-tube hydrocyclone separator 3 via a pressurization pump and a pressurization pipeline. The vertical multi-tube hydrocyclone separator 3 includes a hydrocyclone tank 31 and a plurality of first hydrocyclone tubes 37 arranged in parallel within the hydrocyclone tank 31. The hydrocyclone tank 31 is divided into a first liquid inlet chamber 32, a first overflow chamber 33, a first liquid collection chamber 34, and a first underflow chamber 35 from top to bottom. The liquid inlet of each first hydrocyclone tube 37 is connected to the first liquid collection chamber 34, and the overflow port of each first hydrocyclone tube 37 is connected to the first overflow chamber. The vertical multi-tube cyclone separator 3 is connected to the first underflow chamber 35, and the upper part of the vertical multi-tube cyclone separator 3 is provided with a gas outlet 39 and the lower part is provided with a first liquid-solid mixed phase outlet 38. The feed inlet of the vertical multi-tube cyclone separator 3 is connected to the first liquid inlet chamber 32. The gas outlet 39 of the vertical multi-tube cyclone separator 3 is connected to the first overflow chamber 33. The first liquid-solid mixed phase outlet 38 of the vertical multi-tube cyclone separator 3 is connected to the first underflow chamber 35. The first liquid inlet chamber 32 is connected to the first liquid collection chamber 34. Photocatalytic module 5, the photocatalytic module 5 includes an optical fiber post 51 and a light source 52 that is optically connected to the optical fiber post 51, the end of the optical fiber post 51 away from the light source 52 is located in the first liquid collection cavity 34; A liquid-solid hydrocyclone includes a separation tank 41 and a plurality of second hydrocyclones arranged in parallel within the separation tank 41. The separation tank 41 is divided from top to bottom into a second overflow chamber 42, a second liquid collection chamber 43, and a second underflow chamber 44. The second liquid collection chamber 43 is connected to the first liquid-solid mixed phase outlet 38. The overflow port of the second hydrocyclone is connected to the second overflow chamber 42. The liquid inlet of the second hydrocyclone is connected to the second liquid collection chamber 43. The underflow port of the second hydrocyclone is connected to the second underflow chamber 44. The separation tank 41 is provided with a clear liquid outlet 45 and a second liquid-solid mixed phase outlet 46. The clear liquid outlet 45 is connected to the second overflow chamber 42. The second liquid-solid mixed phase outlet 46 is connected to the reflux catalyst inlet of the buffer tank 2. The gas outlet 39 is connected to a hydrogen purification unit.

[0046] In these embodiments, this embodiment provides a coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device for implementing the above method, the structure of which is as follows: Stripping tower 1 is a packed tower or a plate tower, with a light component gas outlet 39 at the top and a purified water outlet at the bottom. This outlet is connected to a stainless steel pipe via a flange and has an external aluminum silicate fiber insulation layer to ensure low heat loss during transport. Stripping tower 1 operates at a temperature of 80-120℃ and a pressure of 0-0.1 MPaG, and is used to remove wastewater... Volatile pollutants such as hydrocarbons, methanol, and acetone.

[0047] The buffer tank 2 is a vertical cylindrical pressure vessel. Its top is connected to the purified water outlet of the stripping tower 1 through the insulated pipeline. It is used to receive preheated purified water and serve as a mixing and temporary storage unit for the catalyst slurry.

[0048] A fresh catalyst inlet is located on the upper side wall of the tank, which connects to the catalyst preparation tank; The lower part is provided with a reflux catalyst inlet, which is connected to the second liquid-solid mixed phase outlet 46 of the liquid-solid cyclone separator; A variable frequency speed-regulating stirrer (e.g., a three-bladed swept-back impeller) is installed inside the tank to ensure uniform dispersion of the catalyst. Configure an online concentration monitoring sensor (such as a laser turbidity meter or microwave solids meter) to provide real-time feedback of catalyst concentration signals to the PLC control system, and adjust the amount of fresh catalyst added and the return flow rate in conjunction to keep the concentration of the mixed slurry stable at 50-200 mg / L.

[0049] The bottom outlet of the buffer tank 2 is connected to the feed inlet of the vertical multi-tube cyclone separator 3 via a pressurization pump (e.g., a high-pressure diaphragm pump) and a pressurization delivery pipeline.

[0050] The separator integrates multiple parallel first cyclone tubes 37 inside the cyclone tank 31, arranged in an array to save space.

[0051] The upper part is provided with a gas outlet 39, which collects the hydrogen-rich gas escaping from the top of each first cyclone tube 37; The lower part is provided with a first liquid-solid mixed phase outlet 38, which is connected to the liquid-solid cyclone separator. An optical fiber column 51 is installed in the center of the liquid collection chamber of the cyclone tube, and one end is connected to an external light source 52 through a quartz optical fiber bundle for optical transmission.

[0052] The optical fiber post 51 extends to the liquid collection cavity where the first cyclone tube 37 is located. Its outer surface is a porous quartz structure, allowing the reaction liquid to permeate and contact the light-illuminated area, thus forming the photocatalytic module 5. For example, a focusing device 53 is provided between the optical fiber post 51 and the light source 52 to focus the light source 52 and guide it into the optical fiber post 51.

[0053] The inlet of the liquid-solid hydrocyclone 4 is connected to the outlet 38 of the first liquid-solid mixed phase. The clear liquid outlet 45 discharges the treated liquid phase and sends it to the downstream biochemical unit; the outlet 46 of the second liquid-solid mixed phase outputs high-concentration catalyst slurry, most of which is returned to the reflux catalyst inlet of the buffer tank 2 via the reflux pipeline, and the remainder can be switched to the regeneration system.

[0054] Gas outlet 39 is connected to a hydrogen purification unit via a stainless steel pipeline. This unit includes a condenser, a desulfurization adsorption tower, a palladium-silver alloy membrane separator, a hydrogen storage tank, or is directly connected to the plant's hydrogen pipeline network.

[0055] In some embodiments, the first liquid inlet chamber 32 is connected to the first liquid collection chamber 34 through multiple transfer pipes 36; each transfer pipe 36 is arranged at intervals along the circumference of the cyclone tank 31 to homogenize the feed.

[0056] In some embodiments, the stripping tower 1, buffer tank 2, vertical multi-tube hydrocyclone 3, and liquid-solid hydrocyclone 4 are connected in series via insulated pipelines, so that the purified water exchanges heat with the fresh catalyst slurry in the insulated pipelines.

[0057] In this embodiment, the stripping tower 1, buffer tank 2, vertical multi-tube hydrocyclone 3, and liquid-solid hydrocyclone are not isolated units, but are connected by an insulated pipeline system to achieve efficient and coordinated heat and material transfer. The heat exchange process between purified water and fresh catalyst slurry is cleverly integrated into the connecting pipelines between the equipment, avoiding the need for separate heat exchangers, simplifying the process, and reducing heat loss.

[0058] The purified water outlet of stripping tower 1 is connected to the inlet of buffer tank 2 via a first-section double-insulated pipeline; the outlet of buffer tank 2 is connected to vertical multi-tube hydrocyclone 3 via a booster pump and a second-section insulated pipeline; the first liquid-solid mixed phase outlet 38 of the hydrocyclone is then connected to the liquid-solid hydrocyclone via a third-section insulated pipeline. All pipelines use stainless steel inner tubes with aluminum silicate fiber insulation layers.

[0059] For example, the first section of the insulated pipeline is designed as a coaxial sleeve heat exchange structure. Its inner tube is used to transport purified water from stripping tower 1, while the annular gap of the outer tube is used to pass fresh catalyst slurry from the catalyst preparation system. The two flow in opposite directions and exchange heat indirectly through the inner tube wall.

[0060] After passing through the heat exchange section, the purified water is cooled to 65-75℃ and enters the buffer tank 2, while the fresh catalyst slurry is preheated to 60-80℃, which just meets the optimal starting temperature window for the photocatalytic reaction.

[0061] This design eliminates the need for plate or shell-and-tube heat exchangers in traditional processes, reducing equipment investment and floor space. Furthermore, because the heat exchange process is completed within a closed, insulated pipeline, it avoids secondary pollution or heat loss caused by exposure to high-temperature wastewater. More importantly, the preheated catalyst slurry exhibits reduced viscosity and improved dispersibility, making it easier to form a uniform suspension after entering the first cyclone tube 37, significantly enhancing photocatalytic efficiency.

[0062] In some embodiments, the surface of the optical fiber post 51 is sequentially provided with a wear-resistant ceramic substrate, a photocatalytic catalyst layer, and... An erosion-resistant protective layer; wherein the thickness of the wear-resistant ceramic substrate is 0.2 mm to 0.4 mm, and the thickness of the photocatalytic catalyst layer is 0.05 mm to 0.1 mm. The thickness of the erosion-resistant protective layer is 0.02 mm to 0.05 mm.

[0063] In this embodiment, the optical fiber post 51 is not a bare quartz optical fiber, but rather has three functionalized coatings sequentially constructed on its outer surface, forming a "wear-resistant ceramic underlayer, a photocatalytic catalyst layer, and..." The composite structure of the "erosion-resistant protective layer" effectively solves industrial problems such as easy loss of traditional suspended catalysts, easy wear of immobilized carriers, and strong corrosiveness of high-salt wastewater.

[0064] The wear-resistant ceramic underlayer, made of alumina-zirconia composite ceramic, is directly coated onto the surface of the quartz optical fiber substrate using a plasma spraying process, with a thickness controlled between 0.2 mm and 0.4 mm. This layer provides high hardness and excellent thermal matching, preventing mechanical damage to the optical fiber body from high-speed swirling liquid flow, while also serving as a robust adhesion substrate for the catalyst layer.

[0065] The photocatalyst layer is coated on the wear-resistant ceramic substrate, and is composed of... The heterojunction nanocomposite material was prepared by sol-gel loading with a thickness of 0.05 mm to 0.1 mm. This thickness ensures sufficient active site density while avoiding insufficient photon penetration depth or internal stress cracking due to excessive thickness.

[0066] The erosion-resistant protective layer consists of an outermost dense amorphous silica film, coated using a chemical vapor deposition process, with a thickness ranging from 0.02 mm to 0.05 mm. This layer exhibits high chemical inertness, effectively preventing the erosion of the catalyst layer by high-salt, high-pH wastewater; simultaneously, its smooth surface significantly reduces fluid shear resistance, minimizing catalyst detachment. It is worth noting that... It has high transmittance in the ultraviolet region and does not affect the light flux required for photocatalytic reactions.

[0067] In some embodiments, the light source 52 is an artificial light source 52 or sunlight, the optical fiber post 51 is arranged along the axial direction of the first liquid collection cavity 34, and the depth of the optical fiber post 51 extending into the first liquid collection cavity 34 is 60% to 90% of the height of the first cyclone tube 37.

[0068] In this embodiment, the photocatalytic module 5 has high flexibility and engineering adaptability in the selection and spatial arrangement of the light source 52, specifically reflected in the following two aspects: Artificial Light Source Mode 52: The light source 52 is a high-power ultraviolet LED array, suitable for nighttime, rainy days, or conditions requiring high stability of hydrogen production rates. In this mode, the system can operate continuously for 24 hours, with precise controllable light intensity and density, making it suitable for industrial deployment.

[0069] Solar Light Mode: In areas with abundant solar resources (such as the Northwest Coal Chemical Base), the light source 52 can be replaced with a concentrating solar thermal collector-splitter system. This system collects sunlight through Fresnel lenses or parabolic reflectors, and separates the 300-420 nm ultraviolet-near-ultraviolet wavelengths through filters before coupling them to the fiber optic column 51. This mode requires no external power, significantly reducing operating costs and enabling zero-carbon hydrogen production.

[0070] The two light sources 52 can be switched via a quick-connect interface, and the device has the ability to adapt to different light sources 52.

[0071] The fiber optic post 51 is positioned at the center of the cyclone tank 31, with its lower end (the end furthest from the light source 52) extending into the first liquid collection chamber 34 to a depth of 60% to 90% of the total height of the first cyclone tube 37. For example, when the height of the first cyclone tube 37 is 1.2m, the fiber optic post 51 is inserted into the first liquid collection chamber 34 to a depth of 0.72m to 1.08m.

[0072] This design is based on the results of joint simulation of flow field and light field: if the insertion depth is less than 60%, the high-concentration catalyst region at the bottom (enriched by centrifugal sedimentation) cannot be effectively irradiated, resulting in a reaction dead zone. If the insertion depth is greater than 90%, the low-solids region near the outlet is over-illuminated, causing photon waste and making it susceptible to light transmission stability affected by bubble disturbance.

[0073] In addition, the axial arrangement avoids flow channel blockage or local eddies caused by sidewall installation, ensuring the stability of three-phase flow.

[0074] In some embodiments, the photocatalyst layer is A piezoelectric-photonic bifunctional catalyst layer composed of lead zirconate titanate in a mass ratio of (6.5-7.5):(3.5-2.5).

[0075] In this embodiment, the photocatalyst layer is not a single photocatalyst, but is composed of titanium dioxide. The piezoelectric-photonic bifunctional catalytic layer formed by combining lead zirconate titanate (PZT) in a specific mass ratio is designed to fully utilize the dual excitation of dynamic mechanical stress generated by the swirling shear field and ultraviolet radiation in this device to achieve synergistic mechanical-photonic catalysis.

[0076] In composite catalysts, The mass ratio of PZT to PZT is (6.5–7.5): (3.5–2.5), with an example of 7:3. Anatase nanoparticles provide excellent photocatalytic activity; PZT is a perovskite-structured piezoelectric ceramic powder that can generate a built-in electric field under mechanical disturbance.

[0077] When the PZT ratio is less than 25%, the piezoelectric effect is weak and the synergistic gain is not obvious; when the PZT ratio is greater than 35%, the overall photocatalytic efficiency is reduced and the environmental risk is increased because PZT itself has weak photoresponse and contains lead. A 7:3 ratio achieves the best balance between COD degradation rate, hydrogen production and material stability.

[0078] During the operation of the vertical multi-tube cyclone separator 3: ultraviolet light irradiation. This generates electrons and holes. The high-speed swirling liquid flow produces periodic shear forces and pressure fluctuations on the surface of the fiber pillar 51, causing deformation of the PZT lattice and generating positive and negative piezoelectric charges on the surface; the piezoelectric field generated by PZT effectively drives... Photogenerated electrons migrate from the electron pool to PZT, significantly suppressing electron-hole recombination and prolonging carrier lifetime. Simultaneously, piezoelectric polarization enhances interfacial charge transfer, promoting… Restore to and the oxidation of organic matter into .

[0079] In some embodiments, the second liquid-solid mixed phase outlet 46 of the liquid-solid cyclone separator is provided with a pulse backflushing mechanism; the second liquid-solid mixed phase outlet 46 of the liquid-solid cyclone separator is connected to the reflux catalyst inlet of the buffer tank 2 and the catalyst regeneration system respectively via a diversion pipe, and a control valve is provided on the diversion pipe.

[0080] In this embodiment, the liquid-solid cyclone separator has two key improvements at the discharge end and the outlet pipeline: the second liquid-solid mixed phase outlet 46 is equipped with a pulse backflushing mechanism, and the second liquid-solid mixed phase outlet 46 is equipped with a diversion pipeline with a control valve, which are used to prevent equipment blockage and realize closed-loop-regeneration synergistic management of the catalyst, respectively.

[0081] The inner wall of the second liquid-solid mixed phase outlet 46 of the liquid-solid cyclone separator is circumferentially arranged with multiple compressed air nozzles, which are connected to a pulse solenoid valve and a clean instrument air source.

[0082] For example, the control system automatically triggers backflushing based on the running time or the differential pressure sensor signal (monitoring the pressure drop before and after the second liquid-solid mixture outlet 46): every 2 hours of operation, or when the differential pressure exceeds the set threshold, the pulse solenoid valve opens, releasing high-pressure airflow to impact the inner wall of the second liquid-solid mixture outlet 46.

[0083] The pulse backflushing mechanism effectively removes catalyst agglomerates or inorganic scale adhering to the outlet 46 of the second liquid-solid mixed phase, preventing poor discharge or complete blockage caused by long-term deposition of high-solids slurry. Pilot operation shows that the addition of this mechanism extends the continuous trouble-free operation cycle of the liquid-solid cyclone separator.

[0084] The second liquid-solid mixed phase outlet 46 is not a single reflux path, but is divided into two paths through a three-way diversion pipe: the first branch is connected to the reflux catalyst inlet of the buffer tank 2 for the main circulation; the second branch is connected to the catalyst regeneration system (including ultrasonic cleaning tank, low temperature roasting furnace, etc., not shown in detail in the figure) for the online recovery of deactivated catalyst.

[0085] The diversion pipeline is equipped with an electric proportional control valve (such as a pneumatic V-type ball valve or an intelligent regulating valve), which is adjusted by the PLC system according to the catalyst activity monitoring signal (from the sensor in the buffer tank 2) to regulate the flow distribution between the two channels.

[0086] This design avoids the catalyst waste caused by traditional periodic evacuation, while ensuring the overall stability of the system's activity. Total catalyst consumption is reduced, leading to a decrease in the cost per ton of water treated.

[0087] In some embodiments, the stripping tower 1 is a packed tower, the packed tower is filled with stainless steel ring saddle packing, the bottom of the packed tower is equipped with a steam coil heating system, and the top of the packed tower is equipped with an exhaust port, which is connected to the feed end of the waste oil recycling system through a pipeline.

[0088] In this embodiment, the stripping tower 1 adopts a packed tower structure and integrates high-efficiency packing, a tower bottom heating system, and a light component recovery pipeline to achieve efficient removal and resource utilization of volatile organic compounds in the water of coal-to-olefins production.

[0089] The stripping tower 1 is a vertical cylindrical pressure vessel filled with stainless steel annular saddle packing. This packing combines the high throughput of annular packing with the excellent wettability of saddle packing, providing a sufficient gas-liquid contact interface under low pressure drop conditions, and significantly improving the removal efficiency of pollutants such as light hydrocarbons, methanol, and acetone.

[0090] The bottom of the reboiler is equipped with a steam coil heating system, consisting of multiple turns of stainless steel coils, through which saturated steam is introduced as the heat source. By adjusting the steam flow rate, the reboiler temperature can be precisely controlled between 80℃ and 120℃, eliminating the need for an additional reboiler and simplifying the equipment structure. This design utilizes waste heat from low-pressure steam in the plant area, reducing energy consumption.

[0091] An exhaust port is located at the top of the tower, and the main components of the discharged gas are: , , Acetone and water vapor. The exhaust port is directly connected to the feed end of the plant's waste oil recycling system (such as the quench oil system or the pyrolysis furnace fuel system) via an insulated stainless steel pipe.

[0092] The olefins and oxygen-containing compounds in the light components have high calorific value and can be recycled as supplementary fuel or raw materials, realizing the transformation of waste into energy.

[0093] In some embodiments, the buffer tank 2 is equipped with a turbine agitator and an online catalyst concentration monitoring sensor. The online catalyst concentration monitoring sensor and the fresh catalyst dosing pump are electrically connected to a controller. The controller controls the fresh catalyst dosing pump to adjust the amount of fresh catalyst added based on the real-time concentration signal sent by the online catalyst concentration monitoring sensor.

[0094] In this embodiment, the buffer tank 2 is equipped with a turbine agitator and an online catalyst concentration monitoring sensor, and an automatic adjustment loop consisting of a controller and a fresh catalyst addition pump is constructed to realize real-time sensing and dynamic replenishment of catalyst concentration, ensuring that the slurry concentration entering the vertical multi-tube cyclone separator 3 is always stable in the optimal range of 50-200 mg / L.

[0095] The turbine agitator is installed on the central axis of the buffer tank 2, and the impeller is a three-bladed straight turbine driven by a variable frequency motor. Compared with traditional anchor or paddle agitators, the turbine structure can generate strong radial flow at low speeds, effectively preventing catalyst particles from settling and agglomerating, while avoiding the breakage of nano-catalysts caused by high shear, thus ensuring the uniformity and stability of the slurry.

[0096] A catalyst concentration online monitoring sensor is installed in the middle of the side wall of buffer tank 2. It can be a laser turbidity-scattering composite sensor or a microwave solid content analyzer, which can output the catalyst mass concentration signal in the slurry in real time.

[0097] The sensor is electrically connected to the controller via a signal line; the fresh catalyst addition pump is also electrically connected to the controller and is used to add fresh slurry from the catalyst preparation tank to the buffer tank 2.

[0098] The control logic is as follows: The controller presets a target concentration value (e.g., 120 mg / L). When the sensor detects that the actual concentration is lower than the lower limit of the set value (e.g., 100 mg / L), the controller starts the dosing pump to add high-concentration fresh catalyst slurry proportionally; when the concentration rises back to the upper limit (e.g., 140 mg / L), the dosing stops.

[0099] Example: If the recirculated catalyst experiences a decrease in activity due to deactivation, the system will automatically increase the fresh catalyst replenishment rate to maintain a constant total catalytic activity.

[0100] In some embodiments, the liquid-solid hydrocyclone 4 includes a first-stage second hydrocyclone and a second-stage second hydrocyclone arranged in series; the large-diameter catalyst particles separated from the underflow port of the first-stage second hydrocyclone are directly returned to the buffer tank 2, and the overflow port of the first-stage second hydrocyclone is connected to the feed port of the second-stage second hydrocyclone; the underflow port of the second-stage second hydrocyclone concentrates the slurry containing small-diameter catalyst particles to a solid content of 20 wt% to 30 wt% and then returns it to the buffer tank 2; the overflow of the first-stage second hydrocyclone and / or the overflow of the second-stage second hydrocyclone is sent to the post-treatment unit as clarified liquid.

[0101] In this embodiment, the liquid-solid hydrocyclone separator 4 is a staged separation system composed of a first-stage second hydrocyclone tube and a second-stage second hydrocyclone tube connected in series. By utilizing the difference in separation particle size of different second hydrocyclone tubes, the catalyst particles can be graded and reused according to particle size and high-concentration slurry can be prepared, minimizing catalyst loss and optimizing reflux quality.

[0102] The first-stage second hydrocyclone is a large-diameter hydrocyclone, whose inlet receives the liquid-solid mixture from the vertical multi-tube hydrocyclone separator 3. Under centrifugal force, large-diameter catalyst particles are thrown against the wall of the separator and discharged from the underflow outlet, directly returning to the reflux catalyst inlet of the buffer tank 2. These particles are highly active and settle quickly, allowing them to immediately participate in subsequent reactions.

[0103] The overflow outlet discharges a low-solids stream containing fine particles and most of the clarified liquid, which connects to the feed inlet of the second-stage second cyclone separator. This second-stage second cyclone separator is a small-diameter, high-precision hydrocyclone specifically designed to capture fine catalyst particles. Its underflow outlet outputs a high-concentration slurry with a solids content of 20 wt% to 30 wt% (verified by an online density meter). This concentrated slurry is also returned to buffer tank 2 as a high-activity replenishment source. The overflow outlet produces clarified liquid, which is sent as clarified liquid to a post-treatment unit (such as a biological treatment tank or membrane system).

[0104] Large particles are quickly reused, while small particles are efficiently concentrated, avoiding activity loss or excessive reflux load caused by a one-size-fits-all approach. The second-stage underflow has a solids content of 20-30 wt%, significantly reducing reflux water volume and lowering the volume requirement of buffer tank 2 and agitation energy consumption. The two-stage structure disperses the solids load, and the single-stage second cyclone tube is less prone to clogging. Combined with the pulse backflushing mechanism, the system reliability is further improved.

[0105] Another example is provided below: In a large-scale coal-to-olefins process in China, the method of this invention is used to treat purified water by deep treatment coupled with hydrogen production, thereby realizing the recycling and discharge of catalyst. Small-scale and pilot-scale experiments have been completed.

[0106] 1. Material properties and related parameters Coal-to-olefins wastewater is a typical high-temperature liquid-solid two-phase mixture containing fine powder of deactivated catalyst lost from the MTO process, with a concentration of 0.3-0.7 g / L, a median particle size of 2.2 μm, an operating temperature of 95℃, and a COD concentration fluctuating between 1800-2200 mg / L. The main components are methanol, dimethyl ether, and a small amount of acetic acid.

[0107] 2. Vertical multi-tube hydrocyclone separator 3, buffer tank 2, and liquid-solid separation device The vertical multi-tube cyclone separator 3 has a diameter of 0.6 m and a height of approximately 2.8 m. It consists of an upper columnar reaction section and a lower conical separation section, and is composed of eight parallel first cyclone tubes 37. The operating flow rate is 4.5 m / s, and the central negative pressure zone is stabilized at -0.07 MPa. The photocatalytic module 5 integrates an ultraviolet LED light source 52 (light intensity density 80 mW / cm²) to achieve synergy between turbulent shearing and light radiation field. The asymmetric flow-dividing buffer tank 2 has a diameter of 2.40 m, a total height of 3.50 m, and an effective volume of approximately 12 m³. The liquid-solid cyclone separator 4 has a cylindrical section diameter of 0.30 m and an outlet diameter of 0.10 m. It has parallel dual interfaces: the underflow pipeline is connected through a Y-type symmetrical distributor, and the branch pipe diameter is 0.08 m.

[0108] 3. Implementation process Purified water from the bottom of stripping tower 1 is tangentially introduced into buffer tank 2 and instantaneously mixed with reflux slurry with a solid content of 25 wt%, ensuring uniform dispersion of the 5.0 mm supported piezoelectric catalyst. The mixed slurry is pumped into a vertical multi-tube hydrocyclone, where fluid shear drives particle deformation to generate electricity, degrade organic matter, and synergistically produce hydrogen. The negative pressure zone formed at the center of the reactor core attracts hydrogen bubbles to desorb towards the axis and discharges them through the first overflow chamber 33. The reacted slurry enters a hydrocyclone separator for retention and metabolic recycling.

[0109] 4. The experimental results are shown in Table 1 below.

[0110] The experimental data above show that, using the device and method of the present invention, under the same treatment scale (50 m³ / h), a breakthrough has been achieved compared with the traditional process that only treats wastewater: for the first time, in-situ production of hydrogen from coal-to-olefins wastewater has been realized, with an average yield of 24.5 mmol / g·L.

[0111] Meanwhile, through closed-loop catalyst circulation and anti-clogging design, the continuous operation cycle of the system is significantly increased from 820 hours in the traditional process to over 1500 hours, solving the long-standing industry problems of catalyst loss and equipment clogging. This verifies the technical feasibility and significant economic benefits of this invention, which, through the cascade utilization of waste heat and the synergistic effect of cyclone-light-negative pressure multi-field, achieves deep wastewater treatment while successfully converting pollutants into high-value-added hydrogen resources.

[0112] Furthermore, the inventor conducted the following comparative experiments: The experimental standard was based on Example 1 (flow rate 4.5 m / s, light intensity 80 mW / cm², negative pressure -0.07 MPa, three-layer composite coating). The results are shown in Table 2 below:

[0113] As shown in Table 2, when the central negative pressure field is missing (Comparative Example 1), hydrogen microbubbles cannot desorb in time and adhere to the catalyst surface, causing product inhibition and resulting in a 49.8% decrease in hydrogen production rate compared to the example. When the flow rate is too low (Comparative Example 2), the swirling shear force is insufficient to activate the catalyst. The piezoelectric effect of the PZT composite catalyst, relying solely on photocatalysis, resulted in a COD removal rate of only 65.4%. When the flow rate was too high (Comparative Example 3), although the reaction kinetics accelerated, the erosion and wear rate of the fiber optic coating increased dramatically, preventing the equipment from operating for extended periods. The above data demonstrates that the combination of 4.0-5.5 m / s and -0.05 to -0.10 MPa requires precise control and is not a conventional choice easily obtained by those skilled in the art through a limited number of experiments.

[0114] When using a conventional single-layer impregnation coating (Comparative Example 4), due to the lack of a wear-resistant underlayer and erosion-resistant surface layer, the catalyst wear rate reached as high as 42.3% after 800 hours of operation in high-flow-rate slurry, and the activity decreased significantly due to the shedding of active components. This proves that the described three-layer composite protective structure is a non-obvious design for the high solids content and high flow rate conditions of coal-to-olefins wastewater.

[0115] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not as limitations; therefore, other examples of exemplary embodiments may have different values.

[0116] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0117] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device, characterized in that, include: The stripping tower is equipped with a purified water outlet; The buffer tank is connected to the purified water outlet of the stripping tower via an insulated pipeline. The buffer tank is equipped with a fresh catalyst inlet and a reflux catalyst inlet, and is equipped with a stirrer and a concentration monitoring sensor inside the tank. A vertical multi-tube hydrocyclone separator is provided. The outlet of the buffer tank is connected to the inlet of the vertical multi-tube hydrocyclone separator via a pressurized pump and a pressurized delivery pipeline. The vertical multi-tube hydrocyclone separator includes a hydrocyclone tank and multiple first hydrocyclone tubes arranged in parallel within the hydrocyclone tank. The hydrocyclone tank is divided into a first liquid inlet chamber, a first overflow chamber, a first liquid collection chamber, and a first underflow chamber from top to bottom. The liquid inlet of each first hydrocyclone tube is connected to the first liquid collection chamber, the overflow port of each first hydrocyclone tube is connected to the first overflow chamber, and the underflow port of each first hydrocyclone tube is connected to the first underflow chamber. The vertical multi-tube hydrocyclone separator has a gas outlet at the top and a first liquid-solid mixed phase outlet at the bottom. The inlet of the vertical multi-tube hydrocyclone separator is connected to the first liquid inlet chamber, the gas outlet of the vertical multi-tube hydrocyclone separator is connected to the first overflow chamber, the first liquid-solid mixed phase outlet of the vertical multi-tube hydrocyclone separator is connected to the first underflow chamber, and the first liquid inlet chamber is connected to the first liquid collection chamber. A photocatalytic module, comprising an optical fiber column and a light source optically connected to the optical fiber column, wherein the end of the optical fiber column away from the light source is located within the first liquid collection cavity; A liquid-solid hydrocyclone includes a separation tank and a plurality of second hydrocyclones arranged in parallel within the separation tank. The separation tank is divided from top to bottom into a second overflow chamber, a second liquid collection chamber, and a second underflow chamber. The second liquid collection chamber is connected to the outlet of the first liquid-solid mixed phase. The overflow port of the second hydrocyclone is connected to the second overflow chamber, the liquid inlet of the second hydrocyclone is connected to the second liquid collection chamber, and the underflow port of the second hydrocyclone is connected to the second underflow chamber. The separation tank is provided with a clear liquid outlet and a second liquid-solid mixed phase outlet. The clear liquid outlet is connected to the second overflow chamber, and the second liquid-solid mixed phase outlet is connected to the reflux catalyst inlet of the buffer tank. The gas outlet is connected to a hydrogen purification unit.

2. The coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device according to claim 1, characterized in that, The first liquid inlet chamber is connected to the first liquid collection chamber through multiple transfer pipes; each of the transfer pipes is spaced apart along the circumference of the cyclone tank.

3. The coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device according to claim 1, characterized in that, The stripping tower, buffer tank, vertical multi-tube hydrocyclone and liquid-solid hydrocyclone are connected in series through insulated pipelines, so that the purified water exchanges heat with the fresh catalyst slurry in the insulated pipelines.

4. The coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device according to claim 1, characterized in that, The surface of the optical fiber pillar is sequentially provided with a wear-resistant ceramic substrate, a photocatalytic catalyst layer, and... An erosion-resistant protective layer; wherein the thickness of the wear-resistant ceramic substrate is 0.2 mm to 0.4 mm, and the thickness of the photocatalytic catalyst layer is 0.05 mm to 0.1 mm. The thickness of the erosion-resistant protective layer is 0.02 mm to 0.05 mm.

5. The coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device according to claim 1, characterized in that, The light source is an artificial light source or sunlight. The optical fiber column is arranged along the center of the first liquid collection cavity. The depth of the optical fiber column extending into the first liquid collection cavity is 60% to 90% of the height of the first cyclone tube.

6. The coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device according to claim 4, characterized in that, The photocatalytic catalyst layer is A piezoelectric-photonic bifunctional catalyst layer composed of lead zirconate titanate in a mass ratio of (6.5-7.5):(3.5-2.5).

7. The coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device according to claim 1, characterized in that, The second liquid-solid mixed phase outlet of the liquid-solid cyclone separator is equipped with a pulse backflushing mechanism; the second liquid-solid mixed phase outlet of the liquid-solid cyclone separator is connected to the reflux catalyst inlet of the buffer tank and the catalyst regeneration system respectively via a diversion pipe, and a control valve is provided on the diversion pipe.

8. The coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device according to claim 1, characterized in that, The stripping tower is a packed tower, which is filled with stainless steel ring saddle packing. The bottom of the packed tower is equipped with a steam coil heating system, and the top of the packed tower is equipped with an exhaust port, which is connected to the feed end of the waste oil recycling system through a pipeline.

9. The coal-to-olefins production water deep treatment coupled with photocatalytic hydrogen production device according to claim 1, characterized in that, The buffer tank is equipped with a turbine agitator and an online catalyst concentration monitoring sensor. The online catalyst concentration monitoring sensor and the fresh catalyst dosing pump are electrically connected to the controller. The controller controls the fresh catalyst dosing pump to adjust the amount of fresh catalyst added based on the real-time concentration signal sent by the online catalyst concentration monitoring sensor.

10. A method for deep water treatment coupled with photocatalytic hydrogen production in coal-to-olefins production, applied to the apparatus as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S100: Water from coal-to-olefins production is fed into a stripping tower and heated and / or depressurized at 80°C to 120°C to remove light hydrocarbons and volatile pollutants; the resulting purified water is transported through an insulated pipeline and exchanged with a fresh catalyst slurry to preheat the fresh catalyst slurry to 60°C to 80°C. S200: The preheated fresh catalyst slurry is mixed with the reflux catalyst concentrate from the liquid-solid hydrocyclone separator in a buffer tank. The catalyst concentration in the mixture is adjusted to 50 mg / L to 200 mg / L. The mixed fluid is pressurized and sent to a vertical multi-tube hydrocyclone separator. The vertical multi-tube hydrocyclone separator is equipped with a photocatalytic module. Through the synergistic effect of the cyclone shear field, the light radiation field and the central negative pressure field, photocatalytic degradation of organic pollutants and hydrogen production are carried out simultaneously with gas-liquid-solid three-phase separation. The hydrogen-rich gas obtained after separation is purified and then output. S300: The liquid-solid mixture after hydrocyclone separation enters the liquid-solid hydrocyclone separator. The separated liquid phase is sent to the post-processing unit. The concentrated slurry containing the catalyst is returned to the buffer tank for recycling. A portion of the deactivated catalyst is periodically discharged to maintain the catalytic activity of the system.

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