A coalescence-enhanced cyclone separator and separation method for oil droplet removal from gas

Abstract

This invention relates to a coalescing-enhanced cyclone separation device and method for removing oil droplets from gas. The device includes a cylindrical body divided into an inlet cylindrical section with a tangential inlet. Below the inlet cylindrical section are sequentially coaxially connected primary cyclone section, secondary cyclone section, and bottom oil storage section. Above the inlet cylindrical section is a top filter section coaxially connected to it. Coalescing components are attached to the inner walls of the inlet cylindrical section, primary cyclone section, and secondary cyclone section. A bottom coalescing triangle is located at the center of the bottom surface of the bottom oil storage section. The top filter components are coaxially disposed within the top filter section. This invention combines cyclone separation and coalescing separation technologies, utilizing centrifugal force and the adhesive effect of coalescing fibers to capture and coalesce fine oil droplets into larger droplets, which ultimately flow into the bottom oil storage section, achieving gas purification and effectively separating small-scale, wide-range oily droplets from the gas. It has advantages such as high separation accuracy, high efficiency, compact structure, and convenient maintenance.

Description

Technical Field

[0001] This invention relates to the field of oil and gas separation technology, specifically to a coalescence-enhanced cyclone separation device and method for removing oil droplets from gas. Background Technology

[0002] Supercritical CO2 turbine power generation systems are small, fast-response, and highly efficient power generation systems with broad application prospects in power, military, and aerospace fields. As a closed-loop system operating at high temperature, high pressure, and high speed, supercritical CO2 turbine power generation systems require zero external leakage and no need for gas replenishment. The carbon dioxide working fluid in the turbine and compressor flows through a dry gas seal to the low-pressure gearbox. Leaked carbon dioxide needs to be recovered and reintroduced into the main circulation loop. However, since carbon dioxide entering the low-pressure gearbox mixes with volatile lubricating oil vapor, and the loop system cannot accept lubricating oil particles carried by the carbon dioxide flow, oil-gas separation is required before carbon dioxide is reinjected into the main circulation loop. The technical challenge in achieving this goal lies in the small size and wide particle size range of the lubricating oil particles in carbon dioxide. Traditional oil-gas separation methods are insufficient to meet the purification requirements of carbon dioxide and cannot guarantee the safe operation of the main circulation loop.

[0003] Cyclone separation is a field separation method based on the density difference between two phases, utilizing the centrifugal force generated by high-speed rotation to separate the two phases. It belongs to the physical separation technology in the field of oil and gas separation and is commonly used for separating fine oil droplets. It has a series of advantages such as large processing capacity, compact structure, and simple operation. A hydrocyclone is a highly efficient unit device that uses cyclone separation technology to separate two-phase systems. However, due to limitations imposed by turbulent diffusion and the influence of fluid phase differences, conventional hydrocyclones can only handle oil droplets with a particle size greater than 10 μm. In practical industrial applications, it is often coupled with other oil and gas separation technologies to achieve high-precision oil and gas separation.

[0004] Coalescing separation utilizes coalescing fibers as a medium to allow finely dispersed oil droplets to coalesce and grow through adhesion to the medium's surface, thus achieving rapid separation of fine oil droplets in a gas-liquid system. It offers advantages such as continuous operation, high efficiency, small size, simple maintenance, and self-cleaning properties. Coalescing fibers can capture fine oil droplets in the gas and merge small droplets into larger ones. The essential process of fiber coalescing separation involves the capture, coalescence, and growth of fine oil droplets through wetting coalescence on the material surface and collisional coalescence within microchannels. The fiber material surface serves as both the medium for the coalescence and growth of captured oil droplets and the bridge for transport and transfer of the coalesced droplets within the fiber. The coalesced large oil droplets, under the influence of the drag force of the continuous phase and their own gravity, undergo deformation and transfer (between-fiber transfer) until they detach from the fiber surface, completing the separation of the two phases. Furthermore, coalescing fibers can effectively reduce splashing and rebound of oil droplets against the wall in the cyclone inlet area and annular channel, reduce the formation of fine oil droplets from droplet breakage, and enhance the coalescence and capture effect of the liquid film on the wall. Therefore, fiber coalescence separation technology has great potential in the field of high-precision gas purification to achieve the separation of fine oil droplets.

[0005] Chinese invention patent (CN111156089A) discloses a pre-gas-liquid separator and method for a gas turbine air filtration system. This invention reduces liquid particles in the gas before it enters the air filtration system through swirling separation using a multi-stage volute, a conical cylinder, and guide vanes, and a one-way metal filter screen, thereby extending the service life of the filtration system and reducing its operation and maintenance costs. However, the device has low separation accuracy and cannot separate tiny-scale lubricating oil particles from the carbon dioxide working fluid.

[0006] Chinese invention patent (CN116020222A) discloses a combined coalescing cyclone separator for natural gas purification, and Chinese utility model patent (CN215842291U) authorizes a high-precision gas-liquid separator. Both patents use a combination of multiple separation methods such as cyclone tubes and coalescing cores to achieve high-precision separation of small droplets. However, both devices are simple series superposition of different separation technologies, resulting in large equipment size and high production costs.

[0007] Chinese invention patent (CN115212668) discloses a coalescing filter element and a coalescing filter. This invention allows gas to pass through the filter element from the outside and then into the supporting inner frame. The filter element then filters the gas, removing particulate matter and purifying it. This invention improves the separation accuracy of the coalescing filter element and avoids secondary entrainment. However, when dealing with lubricating oil particles with a wide range of particle sizes, the presence of large-diameter oil droplets can significantly shorten the lifespan of the coalescing filter element, making operation and maintenance inconvenient. Summary of the Invention

[0008] The purpose of this invention is to address the problems of low separation accuracy, large footprint, low separation efficiency, severe oil droplet entrainment, and difficult operation and maintenance of existing oil-gas separation systems. This invention provides a novel coalescence-enhanced cyclone separation device and method for gas oil droplet removal. This device has the advantages of high separation accuracy, compact structure, high separation efficiency, convenient maintenance, no need for additional power input, and no need to add any chemical reagents.

[0009] Inventive Idea

[0010] The present invention aims to achieve efficient and high-precision oil-gas separation by multi-dimensional coupling of cyclone separation and coalescence separation technologies for gases containing small, wide-range lubricating oil particles. The specific approach is as follows:

[0011] 1. Gas containing oil droplets enters the inlet cylindrical section through a tangential inlet. The cylindrical structure and the helical blades of the cylindrical section force the gas-liquid two-phase fluid to generate strong rotational motion. Due to differences in size and density, the gas and liquid phases exhibit different dynamic characteristics under the coupling effect of the swirling flow field and the gravitational field. In the inlet and annular regions, oil droplets are thrown against the device wall, where they rebound, splash, break up, coalesce, and are captured by the oil film on the wall. The secondary small oil droplets generated by the splashing and breaking up of oil droplets further reduce the average particle size of the oil droplets, increasing the difficulty of high-precision oil-gas separation. Therefore, it is necessary to avoid the rebound and splashing and breaking up of oil droplets and increase the probability of oil droplets being coalesced and captured by the oil film on the wall. The cylindrical coalescing assembly on the inner wall of the inlet cylindrical section enhances the wettability and surface tension of the wall surface through its structure and special materials, consisting of a surface layer of loosely coalesced fibers, a middle layer of densely coalesced fibers, and a bottom layer of circumferentially hollow guiding fibers. The microchannels on the surface of the coalescing fiber can promote the coalescence and growth of oil droplets, increasing the probability of droplets being captured by the oil film on the wall. The flexibility of the coalescing material and the large surface tension within the coalescing assembly further prevent the rebound, splashing, and breakage of oil droplets, enhancing the swirling separation of the device and achieving coarse separation of oil and gas.

[0012] 2. The inverted conical structure of the primary and secondary swirl sections further increases the rotational speed of the gas, enhancing the centrifugal force of the oil droplets. This causes smaller oil droplets to move to the surface of the coalescing components in the primary and secondary swirl sections, where they are captured by the oil film on the surface. These coalescing components consist of a surface layer of loosely coalesced fibers, a middle layer of densely coalesced fibers, and a bottom layer of radially hollow guiding fibers. After the fine oil droplets coalesce and grow on the surface of the coalesced fibers and within the micropores, under the drag of the continuous phase fluid and their own gravity, they undergo deformation, transfer, and inter-fiber transmission. They move from the loosely coalesced fibers and through the densely coalesced fibers to the radially hollow guiding fibers, and then along the device wall through the underflow port into the bottom oil storage section, thus achieving the separation of small oil droplets.

[0013] 3. The airflow moving upward through the overflow pipe to the top filter section with the internal swirling flow is evenly dispersed on the surface of the pre-filter layer of the top filter assembly under the action of the top gas distributor. Under the action of gas driving force, the gas passes through the coalescing filter layer made of multiple coalescing fibers, and the gas is finally purified and discharged through the purified gas outlet. A very small number of fine oil droplets coalesce and grow between the coalescing fibers in the coalescing filter layer. When the size exceeds the critical slippage size, they are discharged through the drain layer to the oil guide groove. Under the action of the oil guide groove, they flow to the positioning contact groove of the first-stage swirling section, and through the guiding fibers at the bottom of the coalescing assembly of the first and second-stage swirling sections, they flow to the bottom oil storage section.

[0014] 4. The bottom coalescing triangle of the bottom oil storage section can enhance the internal swirling flow of gas and effectively backmix the lubricating oil at the bottom of the wall. The stored lubricating oil is discharged and recovered through the oil drain after the device has been running for a certain period of time.

[0015] In summary, the coalescence-enhanced cyclone separation device and method for oil droplet removal from gas of the present invention can achieve high-precision separation of small-scale, wide-range oily particles in gas.

[0016] This invention is achieved through the following technical solution:

[0017] A coalescence-enhanced cyclone separation device for oil droplet removal from gas is characterized in that the separation device comprises: a cylindrical body, the body of which is divided into an inlet cylindrical section with a tangential inlet; the lower part of the inlet cylindrical section consists of a primary cyclone section, a secondary cyclone section, and a bottom oil storage section that are coaxially connected to each other; the upper part of the inlet cylindrical section is a top filter section that is coaxially connected to the inlet cylindrical section; a cylindrical section coalescence assembly, a primary cyclone section coalescence assembly, and a secondary cyclone section coalescence assembly are respectively attached to the inner walls of the inlet cylindrical section, the primary cyclone section, and the secondary cyclone section; a bottom coalescence triangle is provided at the center of the bottom surface of the bottom oil storage section; and the top filter assembly is coaxially arranged in the top filter section.

[0018] The top filter section has a purified gas outlet at the top and an oil guide groove at the bottom. The top filter assembly is equipped with a cone-shaped top gas distributor filled with round holes.

[0019] An overflow pipe with vertical connection is provided at the center of the inlet cylindrical section, and a cylindrical section spiral blade is located between the inlet cylindrical section body and the overflow pipe. The overflow pipe contains the overflow pipe spiral blade, and an oil guide groove is also provided in the inner wall of the inlet cylindrical section body. The upper and lower ends of the oil guide groove are connected to the oil guide groove and the positioning contact groove of the first-stage vortex section, respectively.

[0020] The primary swirl section coalescing assembly and the secondary swirl section coalescing assembly are attached to the inner wall of the cylinder through the positioning contact groove of the primary swirl section and the positioning contact groove of the secondary swirl section, respectively, and gradually thicken, so that the primary swirl section and the secondary swirl section become a gradually narrowing inverted cone structure, and are connected to the bottom oil storage section through the underflow port;

[0021] The bottom oil storage section is equipped with an oil drain port, and the central bottom coalescing triangle extends through the underflow port to the bottom of the secondary swirl section.

[0022] The length-to-diameter ratio L1 / D1 of the inlet cylindrical section is 2-5, the overflow pipe diameter D4 is 1 / 4-1 / 3 of the cylindrical section diameter D1, the spacing N1 between the spiral blades of adjacent cylindrical sections is 1 / 10-1 / 4 of the cylindrical section length L1, the spacing N2 between the spiral blades of adjacent overflow pipes is 1 / 10-1 / 5 of the cylindrical section length L1, the overflow pipe length L11 is 1 / 2-3 / 4 of the cylindrical section length L1, the oil guide groove diameter D11 is 1 / 200-1 / 100 of the cylindrical section diameter D1, and the number is 2-6.

[0023] The diameter D2 of the first-stage swirl section is 1 / 2 to 3 / 4 of the diameter D1 of the cylindrical section, and the cone angle a1 is 40-80°. The diameter D3 of the second-stage swirl section is 1 / 6 to 1 / 2 of the diameter D1 of the cylindrical section, and the cone angle a1 is 10-30°. The thickness t2 of the coalescing component in the first-stage swirl section is equal to the thickness t3 of the coalescing component in the second-stage swirl section.

[0024] The aspect ratio L2 / D5 of the top filter section is 1-3, and the opening ratio Φ of the top gas distributor is 30-70%.

[0025] The cylindrical coalescing assembly consists of three layers: loosely coalesced fibers on the surface, densely coalesced fibers in the middle, and circumferentially hollow guiding fibers at the bottom. The first-stage swirl coalescing assembly and the second-stage swirl coalescing assembly both consist of three layers: loosely coalesced fibers on the surface, densely coalesced fibers in the middle, and radially hollow guiding fibers at the bottom. The bottom coalescing triangle is formed by rolling three layers: loosely coalesced fibers, densely coalesced fibers, and radially hollow guiding fibers. The loosely coalesced fibers are coalesced fibers with a porosity greater than or equal to 50%, the densely coalesced fibers are coalesced fibers with a porosity less than 50%, the circumferentially hollow guiding fibers are coalesced fibers with a hollow conduit structure aligned with the circumferential direction of the device, and the radially hollow guiding fibers are coalesced fibers with a hollow conduit structure aligned with the axial direction of the device.

[0026] The top filter assembly consists of a pre-filter layer, a coalesced filter layer, and a drainage layer made of coalesced fibers. The pre-filter layer is made of coalesced fibers with a porosity of less than 50% arranged in a ring. The coalesced filter layer is made of coalesced fibers with a porosity of less than 40% arranged in a spiral and interlaced manner. The drainage layer is made of coalesced fibers with a porosity of less than 30% arranged in a ring.

[0027] The coalesced fibers are preferably one or more of polytetrafluoroethylene, polyacrylonitrile, and glass fiber.

[0028] This invention also provides a coalescence-enhanced cyclone separation method for gas de-oiling droplets, characterized in that the method includes the following steps:

[0029] a1. The oil-containing gas enters the cylindrical section through the tangential inlet. Under the action of the swirl blades in the cylindrical section, it rotates at high speed. The oil droplets in the gas are thrown to the surface of the coalescing component in the cylindrical section by centrifugal force. They flow along the circumferential hollow guide fiber, through the positioning contact groove wall of the first-stage swirl section and the positioning contact groove wall of the second-stage swirl section, to the bottom oil storage section.

[0030] a2. After the gas undergoes initial cyclone separation, it enters the first-stage and second-stage cyclone sections and is further accelerated. Under the centrifugal force generated by the further high-speed rotation, smaller oil droplets are thrown onto the surface of the coalescing components in the first and second-stage cyclone sections, captured by the coalescing fibers, and transported through the radial hollow guiding fibers to the bottom oil storage section via the positioning contact groove and underflow port in the second-stage cyclone section.

[0031] a3. When the gas separated by the swirling flow reaches the bottom outlet, it is supported by the coalescing triangle at the bottom and migrates to the negative pressure zone in the central area of ​​the separation device. It then moves upward with the internal swirling flow through the overflow pipe to the top filter section. The coalescing triangle can effectively prevent the lubricating oil in the bottom oil storage section from back-mixing and affecting the oil-gas separation effect.

[0032] a4. The gas entering the top filtration section through the overflow pipe is further accelerated by the spiral blades of the overflow pipe and evenly distributed on the surface of the pre-filter layer of the top filter assembly through the top gas distributor. Under the action of the gas driving force, the multi-layer coalescing filter layer filters the gas containing fine oil droplets. The coalesced fine oil droplets pass through the drain layer, oil guide groove, oil guide trough, first-stage swirl section positioning contact groove, and second-stage swirl section positioning contact groove, and are discharged to the bottom oil storage section along the guiding fibers on the wall. The purified gas is discharged through the purified gas outlet.

[0033] Beneficial effects

[0034] This invention utilizes organically coupled coalescence separation and cyclone separation technologies to achieve highly efficient and deep separation of small-scale, wide-range lubricating oil particles in a gas within a confined space. This is achieved by leveraging the characteristics of cyclone fluid motion, the collision, breakup, and coalescence of oil droplets, and the capture, transport, and separation properties of coalesced fibers. The device boasts high separation precision, high efficiency, compact structure, and convenient maintenance. It requires no additional power input and no chemical reagents. Multiple cyclone stages can be added to enhance separation precision. It can be directly installed before the main circulation loop for gas purification. Compared to existing technologies, this invention significantly reduces equipment size, improves separation precision, extends device lifespan, ensures the safety of the main circulation loop, and offers considerable economic benefits. Attached Figure Description

[0035] The accompanying drawings are provided to further illustrate the invention and constitute only a part of this specification to further explain the invention, and do not constitute a limitation thereof.

[0036] The parts in the attached drawings are not necessarily drawn to scale.

[0037] Figure 1 This is a schematic diagram of the principle of the device of the present invention.

[0038] Figure 2 This is a schematic diagram illustrating the enhanced cyclone separation principle of the coalescing component in the device of the present invention.

[0039] Figure 3 This is a half-section assembly diagram of the device of the present invention.

[0040] Figure 4 This is a three-dimensional structural diagram of the device of the present invention.

[0041] Figure 5 This is a schematic diagram of the structural dimensions of the device of the present invention.

[0042] Figure 6(a) is a cross-sectional schematic diagram of the inlet cylindrical section and the cylindrical section coalescing assembly of the device of the present invention, and Figure 6(b) is a schematic diagram of the structural dimensions of the inlet cylindrical section and the cylindrical section coalescing assembly of the device of the present invention.

[0043] Figure 7(a) is a cross-sectional structural diagram of the first-stage swirl section, the second-stage swirl section, the first-stage swirl section coalescing component, and the second-stage swirl section coalescing component of the device of the present invention. Figure 7(b) is a structural dimension diagram of the first-stage swirl section, the second-stage swirl section, the first-stage swirl section coalescing component, and the second-stage swirl section coalescing component of the device of the present invention.

[0044] Figure 8(a) is a schematic diagram of the bottom oil storage section and the bottom coalescing triangular cross-sectional structure of the device of the present invention, and Figure 8(b) is a schematic diagram of the dimensions of the bottom oil storage section and the bottom coalescing triangular structure of the device of the present invention.

[0045] Figure 9(a) is a cross-sectional view of the top filter section and the top membrane module of the device of the present invention, and Figure 9(b) is a dimensional view of the top filter section and the top membrane module of the device of the present invention.

[0046] Figure 10(a) is a three-dimensional structural schematic diagram of the top filter assembly of the device of the present invention, and Figure 10(b) is a cross-sectional schematic diagram of the top filter assembly of the device of the present invention.

[0047] Figure 11(a) is a schematic diagram of the ring arrangement of coalesced fibers in the pre-filtration layer and the drainage layer of the device of the present invention, and Figure 11(b) is a schematic diagram of the spiral staggered arrangement of coalesced fibers in the coalesced filter layer of the device of the present invention.

[0048] In the attached figures, the reference numerals represent the following components and devices: 1: Inlet cylindrical section; 2: Primary swirl section; 3: Secondary swirl section; 4: Bottom oil storage section; 5: Top filter section; 6: Cylindrical section coalescing assembly; 7: Primary swirl section coalescing assembly; 8: Secondary swirl section coalescing assembly; 9: Bottom coalescing triangle; 10: Top filter assembly; 11: Tangential inlet; 12: Cylindrical section helical blade; 13: Overflow pipe; 14: Overflow pipe helical blade; 15: Oil guide groove; 21: Primary swirl section positioning contact groove; 22: Secondary swirl section positioning contact groove; 41: Underflow port; 42: Oil outlet; 51: Top gas distributor; 52: Oil guide groove; 53: Purified gas outlet; 101: Pre-filter layer; 102: Coalescing filter layer; 103: Drainage layer. Detailed Implementation

[0049] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should be understood that these embodiments are for illustrative purposes only and do not constitute a limitation on the scope of the invention. Test methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise stated, all percentages and parts are by weight.

[0050] Example 1:

[0051] In a laboratory setting, an ultrasonic fume generator was used, with deionized water instead of lubricating oil, to simulate oil-droplet-containing gas requiring purification. The device of this invention was then used to treat the gas, with a total gas flow rate of 10 m³ / s. 3 / h, the deionized water flow rate was set up in groups of 2ml / min from 0 to 10ml / min for the experiment, and the coalescing fiber used in the coalescing component was preferably polytetrafluoroethylene fiber.

[0052] Design parameters: Assemble the device of the present invention as shown in the figure, wherein the length-to-diameter ratio L1 / D1 of the inlet cylindrical section is 3, the overflow pipe diameter D4 is 1 / 4 of the cylindrical section diameter D1, the spacing N1 between adjacent cylindrical section spiral blades is 1 / 6 of the cylindrical section length L1, the spacing N2 between adjacent overflow pipe spiral blades is 1 / 6 of the cylindrical section length L1, the overflow pipe length L11 is 1 / 2 of the cylindrical section length L1, and the oil guide groove diameter D11 is 1 / 2 of the cylindrical section diameter D1. There are 4 units in total. The diameter D2 of the first-stage swirl section is half the diameter D1 of the cylindrical section, and the cone angle a1 is 40°. The diameter D3 of the second-stage swirl section is 1 / 6 the diameter D1 of the cylindrical section, and the cone angle a1 is 20°. The thicknesses t1, t2, and t3 of the coalescing components in the cylindrical section, the first-stage swirl section, and the second-stage swirl section are equal. The length-to-diameter ratio L2 / D5 of the top filter section is 2, and the opening ratio Φ of the top gas distributor is 50%.

[0053] Application Results: After processing by the device described in this invention, the gas-liquid separation efficiency of each experimental group was higher than 99.9%, and the final purified gas had a water concentration of less than 0.1 mg / m³. 3 .

[0054] Example 2:

[0055] A scale-up experiment was conducted in the laboratory, using an oil fume generator to simulate gas containing lubricating oil particles and treating the gas using the device of this invention. The total gas flow rate was 40 m³ / s. 3 / h, the oil inlet flow rate of the fume generator was set up in groups of 1ml / min from 0 to 5ml / min for the experiment, and the smoke emission temperature of the fume generator was set up in groups of 50℃ from 150 to 300℃ for the experiment. The coalescing fiber used in the coalescing component was a mixture of stainless steel wire and preferred polytetrafluoroethylene fiber. The oil content in the gas was measured using an aerosol photometer.

[0056] Design parameters: Assemble the device of this invention as shown in the figure, wherein the length-to-diameter ratio L1 / D1 of the inlet cylindrical section is 4, the overflow pipe diameter D4 is 1 / 4 of the cylindrical section diameter D1, the spacing N1 between adjacent cylindrical section spiral blades is 1 / 8 of the cylindrical section length L1, the spacing N2 between adjacent overflow pipe spiral blades is 1 / 6 of the cylindrical section length L1, the overflow pipe length L11 is 3 / 4 of the cylindrical section length L1, and the oil guide groove diameter D11 is 1 / 2 of the cylindrical section diameter D1. There are 4 units in total. The diameter D2 of the first-stage swirl section is half the diameter D1 of the cylindrical section, and the cone angle a1 is 40°. The diameter D3 of the second-stage swirl section is 1 / 6 the diameter D1 of the cylindrical section, and the cone angle a1 is 10°. The thicknesses t1, t2, and t3 of the coalescing components in the cylindrical section, the first-stage swirl section, and the second-stage swirl section are equal. The length-to-diameter ratio L2 / D5 of the top filter section is 1, and the opening ratio Φ of the top gas distributor is 40%.

[0057] Application Results: After processing by the device described in this invention, the oil-gas separation efficiency in each experimental group was higher than 99.8%, and the final purified gas contained less than 0.2 mg / m³ of lubricating oil. 3 .

[0058] Example 3:

[0059] To simulate actual conditions, a pilot-scale experimental setup was constructed. An oil fume generator and compressed air were used to simulate gas containing lubricating oil particles, and the device of this invention was used to treat the gas. The total oil and gas flow rate was set to 72 m³ / s. 3 / h、90m 3 / h、126m 3The experiment was conducted with three gradients of oil flow rate (1 ml / min, 2 ml / min, and 3 ml / min), an outlet pressure of 0.1 MPa, and a pipeline temperature controlled between 50 and 60°C. The oil inlet flow rate of the fume generator was set at 300°C. The coalescing component was composed of a mixture of stainless steel wire, glass fiber, and polytetrafluoroethylene fiber. An aerosol photometer was used to measure the oil content in the gas, and a laser dust particle technology device was used to count oil droplets of different sizes.

[0060] Design parameters: Assemble the device of the present invention as shown in the figure, wherein the length-to-diameter ratio L1 / D1 of the inlet cylindrical section is 4, the overflow pipe diameter D4 is 1 / 4 of the cylindrical section diameter D1, the spacing N1 between adjacent cylindrical section spiral blades is 1 / 10 of the cylindrical section length L1, the spacing N2 between adjacent overflow pipe spiral blades is 1 / 10 of the cylindrical section length L1, the overflow pipe length L11 is 3 / 4 of the cylindrical section length L1, and the oil guide groove diameter D11 is 1 / 4 of the cylindrical section diameter D1. 200, with a quantity of 6. The diameter D2 of the first-stage swirl section is 1 / 2 of the diameter D1 of the cylindrical section, and the cone angle a1 is 40°. The diameter D3 of the second-stage swirl section is 1 / 6 of the diameter D1 of the cylindrical section, and the cone angle a1 is 10°. The thicknesses t1, t2, and t3 of the coalescing components in the cylindrical section, the first-stage swirl section, and the second-stage swirl section are equal. The length-to-diameter ratio L2 / D5 of the top filter section is 1, and the opening ratio Φ of the top gas distributor is 40%.

[0061] Application effect: After being processed by the device described in this invention, the pressure drop of the device under each group of gas flow rates is shown in Table 1.

[0062] Table 1 Pressure drop of the device at different gas flow rates

[0063]

[0064] Table 2 shows the oil-gas separation performance of the device under different gas flow rates at a smoke generation temperature of 308℃ and an oil inlet rate of 2ml / min. The oil-gas separation efficiency in each experimental group was higher than 99.9%, and the final purified gas contained less than 0.1mg / m³ of lubricating oil. 3 .

[0065] Table 2. Oil-gas separation performance of the device under different gas flow rates.

[0066]

[0067] The unit operates at a smoke emission temperature of 308℃ and an oil / gas flow rate of 126 m³ / h. 3 Table 3 shows the oil-gas separation performance under different oil inlet rates at a given rate of / h. The oil-gas separation efficiency for each experimental group was higher than 99.9%, and the final purified gas contained less than 0.1 mg / m³ of lubricating oil. 3 .

[0068] Table 3. Oil-gas separation performance of the device under different oil inlet rates.

[0069]

[0070] To further investigate the device's performance in separating fine oil droplets, a laser dust particle counter was used to measure the droplet size distribution at the inlet and outlet, studying the device's ability to separate small-diameter oil droplets. The system was tested at a smoke generation temperature of 308℃, an oil inlet flow rate of 2 ml / min, and an inlet flow rate of 126 m³ / min. 3 At a rate of / h, the number of oil droplets with different particle sizes at the device inlet and the device purified gas outlet was detected, and the results are shown in Table 4.

[0071] Table 4. Number of oil droplets of different sizes at the inlet and outlet of the device.

[0072]

[0073]

[0074] As can be seen from Table 4, compared with conventional hydrocyclones which can only handle oil droplets with a diameter of 10 μm or larger, the device of the present invention has a very good separation effect on oil droplets with a diameter of 1 μm, and can also achieve a separation efficiency of 98% for oil droplets with a diameter of less than 0.3 μm.

Claims

1. A coalescence-enhanced cyclone separator for oil droplet removal from gas, characterized in that, The separation The device includes: a cylindrical body, which is divided into an inlet cylindrical section with a tangential inlet; the lower part of the inlet cylindrical section consists of a primary swirl section, a secondary swirl section, and a bottom oil storage section that are coaxially connected to each other; the upper part of the inlet cylindrical section is a top filter section that is coaxially connected to the inlet cylindrical section; cylindrical section coalescing components, primary swirl section coalescing components, and secondary swirl section coalescing components are respectively attached to the inner walls of the inlet cylindrical section, the primary swirl section, and the secondary swirl section; a bottom coalescing triangle is provided at the center of the bottom surface of the bottom oil storage section; and the top filter components are coaxially arranged in the top filter section. The top filter section has a purified gas outlet at the top and an oil guide groove at the bottom. The top filter assembly is equipped with a cone-shaped top gas distributor filled with round holes. An overflow pipe with vertical connection is provided at the center of the inlet cylindrical section, and a cylindrical section spiral blade is located between the inlet cylindrical section body and the overflow pipe. The overflow pipe contains the overflow pipe spiral blade, and an oil guide groove is also provided in the inner wall of the inlet cylindrical section body. The upper and lower ends of the oil guide groove are connected to the oil guide groove and the positioning contact groove of the first-stage vortex section, respectively. The primary swirl section coalescing assembly and the secondary swirl section coalescing assembly are attached to the inner wall of the cylinder through the primary swirl section positioning contact groove and the secondary swirl section positioning contact groove, respectively, and gradually thicken, so that the primary swirl section and the secondary swirl section become a gradually narrowing inverted cone structure, and are connected to the bottom oil storage section through the underflow port; The bottom oil storage section is equipped with an oil drain port, and the central bottom coalescing triangle extends through the underflow port to the bottom of the secondary swirl section. The cylindrical coalescing assembly consists of three layers: loosely coalesced fibers on the surface, densely coalesced fibers in the middle, and circumferentially hollow guiding fibers at the bottom. The first-stage swirl coalescing assembly and the second-stage swirl coalescing assembly both consist of three layers: loosely coalesced fibers on the surface, densely coalesced fibers in the middle, and radially hollow guiding fibers at the bottom. The bottom coalescing triangle is formed by rolling three layers: loosely coalesced fibers, densely coalesced fibers, and radially hollow guiding fibers. The loosely coalesced fibers are coalesced fibers with a porosity greater than or equal to 50%, the densely coalesced fibers are coalesced fibers with a porosity less than 50%, the circumferentially hollow guiding fibers are coalesced fibers with a hollow conduit structure aligned with the circumferential direction of the device, and the radially hollow guiding fibers are coalesced fibers with a hollow conduit structure aligned with the axial direction of the device.

2. The coalescence-enhanced cyclone separator for gas de-oiling as described in claim 1, characterized in that, The length-to-diameter ratio L1 / D1 of the inlet cylindrical section is 2-5, the overflow pipe diameter D4 is 1 / 4-1 / 3 of the cylindrical section diameter D1, the spacing N1 between the spiral blades of adjacent cylindrical sections is 1 / 10-1 / 4 of the cylindrical section length L1, the spacing N2 between the spiral blades of adjacent overflow pipes is 1 / 10-1 / 5 of the cylindrical section length L1, the overflow pipe length L11 is 1 / 2-3 / 4 of the cylindrical section length L1, the oil guide groove diameter D11 is 1 / 200-1 / 100 of the cylindrical section diameter D1, and the number is 2-6.

3. The coalescence-enhanced cyclone separator for gas de-oiling as described in claim 1, characterized in that, The diameter D2 of the first-stage swirl section is 1 / 2 to 3 / 4 of the diameter D1 of the cylindrical section, and the cone angle a1 is 40-80°. The diameter D3 of the second-stage swirl section is 1 / 6 to 1 / 2 of the diameter D1 of the cylindrical section, and the cone angle a1 is 10-30°. The thickness t2 of the coalescing component in the first-stage swirl section is equal to the thickness t3 of the coalescing component in the second-stage swirl section.

4. The coalescence-enhanced cyclone separator for gas de-oiling as described in claim 1, characterized in that, The aspect ratio L2 / D5 of the top filter section is 1-3, and the opening ratio Φ of the top gas distributor is 30-70%.

5. The coalescence-enhanced cyclone separator for gas de-oiling as described in claim 1, characterized in that, The top filter assembly consists of a pre-filter layer, a coalesced filter layer, and a drainage layer made of coalesced fibers. The pre-filter layer is made of coalesced fibers with a porosity of less than 50% arranged in a ring, the coalesced filter layer is made of coalesced fibers with a porosity of less than 40% arranged in a spiral and interlaced manner, and the drainage layer is made of coalesced fibers with a porosity of less than 30% arranged in a ring.

6. The coalescence-enhanced cyclone separator for gas de-oiling as described in claim 1 or 5, characterized in that, The coalesced fibers are selected from one or more of polytetrafluoroethylene, polyacrylonitrile, and glass fiber.

7. A method for coalescence-enhanced cyclone separation of oil droplets in gas, comprising using the coalescence-enhanced cyclone separation apparatus for oil droplet removal of gas as described in any one of claims 1-6, characterized in that, The method includes the following steps: a1. Gas containing oil droplets enters the cylindrical section through the tangential inlet. Under the action of the spiral blades in the cylindrical section, it rotates at high speed. The oil droplets in the gas are thrown to the surface of the coalescing component in the cylindrical section by centrifugal force. They flow along the circumferential hollow guide fiber, through the positioning contact groove wall of the first-stage swirl section and the positioning contact groove wall of the second-stage swirl section, to the bottom oil storage section. a2. After the gas undergoes initial cyclone separation, it enters the first-stage and second-stage cyclone sections and is further accelerated. Under the centrifugal force generated by the further high-speed rotation, smaller oil droplets are thrown onto the surface of the coalescing components in the first and second-stage cyclone sections, captured by the coalescing fibers, and transported through the radial hollow guiding fibers to the bottom oil storage section via the positioning contact groove and underflow port in the second-stage cyclone section. a3. When the gas separated by the swirling flow reaches the bottom outlet, it is supported by the coalescing triangle at the bottom and migrates to the negative pressure zone in the central area of ​​the separation device. It then moves upward with the internal swirling flow through the overflow pipe to the top filter section. The coalescing triangle can effectively prevent the lubricating oil in the bottom oil storage section from back-mixing and affecting the oil-gas separation effect. a4. The gas entering the top filtration section through the overflow pipe is further accelerated by the spiral blades of the overflow pipe and evenly distributed on the surface of the pre-filter layer of the top filter assembly through the top gas distributor. Under the action of the gas driving force, the multi-layer coalescing filter layer filters the gas containing fine oil droplets. The coalesced fine oil droplets pass through the drain layer, oil guide groove, oil guide trough, first-stage swirl section positioning contact groove, and second-stage swirl section positioning contact groove, and are discharged to the bottom oil storage section along the guiding fibers on the wall. The purified gas is discharged through the purified gas outlet.

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