A high-gravity rotating bed employing a gas-liquid split-flow liquid distributor

Abstract

This invention provides a high-gravity rotating bed employing a gas-liquid split-flow liquid distributor, comprising a shell and a rotating shaft. The shell has an air outlet at its upper end, an air inlet at its side end, and a liquid outlet at its lower end. The rotating shaft passes through the center of the lower end of the shell and is sealed to the shell via a shaft seal. A rotor is fixed on the rotating shaft, and a dynamic seal is provided between the upper end of the rotor and the shell. A gas-liquid split-flow liquid distributor is arranged on the inner edge of the rotor, with its lower end fixed to the rotor chassis and a feed pipe installed at the center of its upper end. The liquid distributor consists of a cylinder and a liquid-blocking ring at the top of the cylinder. An air intake pipe, a liquid distribution hole, and a pressure-reducing platform are fixed on the cylinder wall. The gas-liquid split-flow liquid distributor used in this invention enables the liquid to achieve a uniform initial distribution in both the axial and circumferential directions, thereby improving the gas-liquid mass transfer efficiency. Furthermore, the liquid distributor of this invention has a simple structure, small size, and is easy to install and use indoors.

Description

Technical Field

[0001] This invention relates to the field of centrifugal rotating bed distillation in separation engineering, and more particularly to a centrifugal rotating bed employing a gas-liquid split-flow liquid distributor. Background Technology

[0002] Separation engineering is an engineering discipline that studies the separation and purification of substances in process industries, involving important process industries such as chemical engineering, oil refining, pharmaceuticals, food, energy, metallurgy, and materials. With economic and social development, chemical separation technology faces new challenges in the face of new separation requirements, such as the preparation of high-purity substances, the separation and purification of biopharmaceuticals, the deep processing of various chemical products, the comprehensive utilization of resources, and the implementation of new environmental governance standards. Developing advanced chemical separation methods and energy-saving, consumption-reducing, environmentally friendly, and intensive separation devices has become a development trend and a hot topic. Supergravity separation technology is a new type of separation technology that has gradually developed in this context and is increasingly attracting widespread attention.

[0003] In 1979, Imperial Chemical Industries (ICI) of the UK pioneered the idea of ​​filling the rotor of rotating equipment with high specific surface area fillers such as glass beads or wire mesh to promote mass transfer, and published the first patent related to hypergravity. In the following years, several more related patents were published. These patents sparked great interest in hypergravity technology in academia and industry, and related basic and applied research followed. In the 1990s, research on hypergravity technology gradually moved from the laboratory to industrial applications. Since the beginning of the 21st century, the application areas of hypergravity technology have further expanded.

[0004] In traditional separation equipment, gas-liquid countercurrent contact devices that rely on the Earth's gravitational field are limited by low flooding point and small effective contact area per unit volume. Factors such as low fluid turbulence intensity, limited flow velocity, and small interphase interface result in low interphase transfer rates, leading to large equipment size, high investment and operating costs. In contrast, in hypergravity separation equipment, the liquid passes through high-speed rotating packing material, forming micro-liquid states such as droplets, filaments, and mists with extremely large specific surface areas under hypergravity. These micro-liquid states rapidly form within the rotating packing material, are collided with and quickly coalesce, and circulate repeatedly. This results in a large interphase mass transfer area and rapid renewal rate, with a continuously large specific surface area, significantly improving the interphase mass transfer rate. Utilizing the hypergravity environment, the liquid surface renewal rate is greatly increased, and gas-liquid mass transfer is greatly enhanced. In engineering applications, a hypergravity machine of approximately 2 meters can replace traditional chemical tower equipment tens of meters high.

[0005] The concentric ring counter-current high-gravity rotating bed device invented by Chinese patent CN101254356A features low pressure drop and high throughput of gas passing through the rotor, reduces the risk of liquid flooding, and effectively improves mass transfer efficiency. However, this type of rotating bed has high requirements for initial liquid distribution, as the quality of initial liquid distribution is closely related to the mass transfer performance of the equipment. While layer-by-layer and stepped distributors of this type can achieve initial liquid distribution, they are not uniformly distributed axially, and the fabrication and installation of the liquid distributors are complex.

[0006] Chinese Patent CN101898047A discloses a high-gravity rotary bed with a coil-type rotating liquid distributor. This distributor utilizes the centrifugal force generated by rotation to distribute liquid. The coil-type liquid distributor offers uniform initial liquid distribution, high operational flexibility, a simple and compact structure, and ease of installation and fabrication, and is widely used in actual production processes. However, when the liquid inlet volume is small, the higher the rotation speed, the worse the uniformity of the liquid flow distribution from the distributor's distribution holes becomes. Fouling affects the distributor's distribution performance, causing some distribution holes to become blocked, resulting in a significant increase in the distribution coefficient.

[0007] The high-gravity rotating bed with a multi-layer cylindrical rotating liquid distributor, as invented in Chinese patent CN101890250A, has few liquid distribution holes on the inner side of the distributor. Due to its height, it tends to accumulate liquid when processing small flow rates. When processing large flow rates, the limited number of distribution holes prevents the liquid from transferring to the next layer in time, also leading to accumulation. Furthermore, its operating range is small.

[0008] The concentric counter-current rotating bed disclosed in Chinese Patent CN101254355 has advantages such as high mass transfer efficiency, easy intermediate feeding, and convenient multi-layer installation. However, this type of rotating bed has high requirements for the initial distribution of the liquid, and the uniformity of the liquid distribution directly affects the mass transfer performance of the equipment. The layer-by-layer partitioned distributor and stepped distributor used in this type of device can achieve the initial distribution of the liquid, but the liquid is not evenly distributed in the axial direction of the moving disk, the porosity of the distributor is low, and it is easy to form a bottleneck in the gas channel inside the tower. The fabrication and installation of the distributor are also relatively complicated. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the purpose of this invention is to provide a high-gravity rotating bed employing a gas-liquid split-flow liquid distributor.

[0010] The objective of this invention is achieved through the following technical solution: a high-gravity rotating bed employing a gas-liquid split-flow liquid distributor, comprising a shell and a rotating shaft; the upper end of the shell is provided with an air outlet, the side end with an air inlet, and the lower end with a liquid outlet;

[0011] The rotating shaft passes through the housing from the center of the lower end of the housing and is sealed to the housing by a shaft seal; a rotor is fixed on the rotating shaft, a dynamic seal is provided between the upper end of the rotor and the housing, and packing is placed inside the rotor;

[0012] The inner edge of the rotor is provided with a gas-liquid split-flow liquid distributor. The lower end of the gas-liquid split-flow liquid distributor is fixed to the rotor chassis. A feed pipe is installed at the center of the upper end of the gas-liquid split-flow liquid distributor. The gas-liquid split-flow liquid distributor consists of a cylinder and a liquid-blocking ring at the top of the cylinder. An air intake pipe, a liquid distribution hole, and a pressure reducing platform are fixed on the cylinder wall.

[0013] Furthermore, a liquid-blocking ring is provided at the top of the gas-liquid split-flow liquid distributor.

[0014] Furthermore, the width of the liquid-blocking ring is 0.04-0.4 times the diameter of the cylinder.

[0015] Furthermore, the rotor is either a single layer or multiple layers arranged concentrically and vertically in series via a rotating shaft.

[0016] Furthermore, the gas-liquid split-flow liquid distributor includes 5-40 air intake pipes and 10-400 liquid distribution holes; the air intake pipes and liquid distribution holes are evenly arranged circumferentially.

[0017] Furthermore, the air intake tube extends into the cylinder, and the air intake tube is a round tube, a square tube, or a conical tube.

[0018] Furthermore, the liquid distribution holes are circular, rectangular, or triangular in shape.

[0019] Furthermore, the pressure reducing platform and the air intake pipe are concentrically installed on the outside of the cylinder, and the diameter of the pressure reducing platform is radially increased.

[0020] The beneficial effects of this invention are that it provides a gas-liquid split-flow liquid distributor that utilizes centrifugal force generated by rotation to achieve axial uniformity and stability in the initial distribution of liquid; it eliminates the mixing phenomenon of gas and liquid in the conventional distributor cavity of traditional gravity distributors, replacing it with a gas-liquid split-flow design where gas passes through an air intake pipe and liquid passes through a liquid distribution hole, thus reducing flooding. The equipment has a simple structure, is easy to replace, and is convenient to install and debug, making it suitable for indoor use. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0022] Figure 2 This is a schematic diagram of the main structure of the gas-liquid split-flow liquid distributor in this embodiment;

[0023] Figure 3 This is a top view of the gas-liquid split-flow liquid distributor in this embodiment;

[0024] Figure 4 This is a three-dimensional schematic diagram of the gas-liquid split-flow liquid distributor of this embodiment;

[0025] Figure 5 This is a graph showing the relationship between the constant plate height HETP and the gas phase kinetic energy factor F at different rotational speeds.

[0026] Figure 6 This is a graph showing the relationship between the theoretical number of trays and rotational speed when the width of the liquid-holding ring is a multiple of the cylinder diameter;

[0027] Figure 7 This is a graph showing the relationship between the distribution coefficient α and the number of liquid distribution holes under different return flow rates;

[0028] Figure 8 This is a graph showing the relationship between the distribution coefficient α and the number of air tubes under different return flow rates;

[0029] Reference numerals: 1. Shaft; 2. Housing; 3. Air inlet; 4. Air outlet; 5. Feed pipe; 6. Liquid outlet; 7. Gas-liquid split liquid distributor; 8. Rotor; 9. Packing; 10. Shaft seal; 11. Dynamic seal; 12. Cylinder; 13. Air duct; 14. Liquid distribution hole; 15. Liquid retaining ring; 16. Pressure reducing platform. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0031] Example 1:

[0032] Reference Figure 1 , 2 3, 4, A high-gravity rotating bed device using a gas-liquid split-flow liquid distributor, comprising a housing 2 and a rotating shaft 1; the housing 2 is provided with an air outlet 4 at the upper end, an air inlet 3 at the side end, and a liquid outlet 6 at the lower end;

[0033] The rotating shaft 1 passes through the housing 2 from the lower center position and is sealed to the housing 2 by a shaft seal 10; a rotor 8 is fixed on the rotating shaft 1, a dynamic seal 11 is provided between the upper end of the rotor 8 and the housing 2, and a packing 9 is placed inside the rotor 8;

[0034] The inner edge of the rotor 8 is provided with a gas-liquid split-flow liquid distributor 7. The lower end of the gas-liquid split-flow liquid distributor 7 is fixed to the chassis of the rotor 8. The upper center of the gas-liquid split-flow liquid distributor 7 is equipped with a feed pipe 5. The gas-liquid split-flow liquid distributor 7 is composed of a cylinder 12 and a liquid-blocking ring 15 at the top of the cylinder. An air intake pipe 13, a liquid distribution hole 14 and a pressure reducing platform 16 are fixed on the wall of the cylinder 12.

[0035] The top of the gas-liquid split liquid distributor 7 is provided with a liquid-blocking ring 15.

[0036] The rotor 8 is either a single layer or multiple layers arranged concentrically and vertically in series via a rotating shaft.

[0037] The air intake tube 13 extends into the cylinder 12, and the air intake tube 13 can be a round tube, a square tube, or a conical tube.

[0038] The liquid distribution hole 14 is circular, rectangular or triangular in shape.

[0039] The pressure reducing platform 16 and the air intake pipe 13 are concentrically installed on the outside of the cylinder 12, and the diameter of the pressure reducing platform 16 increases radially.

[0040] Gas-liquid flow path within the device: The gas phase enters the high-gravity rotating bed through the inlet 3. Under pressure, the gas phase passes through the packing 9 in the rotor 8 to reach the inner edge of the rotor 8, and then exits the high-gravity rotating bed through the pressure reducing platform 16 and the air intake pipe 13 of the gas-liquid split-flow liquid distributor 7, exiting through the outlet 4. The liquid enters the liquid distributor through the feed pipe 5 and forms a liquid layer on the inner wall of the distributor's cylinder. Under centrifugal force, the liquid flows out from the distribution hole 14, reaches the inner edge of the rotor 8, then passes through the packing 9 inside the rotor 8 to reach the outer edge of the rotor 8, and finally collects at the bottom of the rotating bed, exiting the device through the outlet 6.

[0041] The principle of supergravity distillation: The liquid in the rotor packing 9 is torn apart by centrifugal force to form liquid film, liquid filament and liquid droplet, generating a rapidly renewed phase interface, which greatly increases the flow rate of the gas and liquid phase and the effective specific surface area of ​​the packing. Under the conditions of uniform dispersion, high mixing and rapid interface renewal, the liquid and gas come into countercurrent contact in the curved channel at a very high relative velocity, so that the gas and liquid phase can carry out efficient mass transfer when passing through each layer of packing, and the mixture can be separated and purified in a short time.

[0042] Example 2:

[0043] Reference Figure 1 , 2 3, 4. A high-gravity rotating bed employing a gas-liquid split-flow liquid distributor is used in total reflux distillation for thermal model experiments. The working process and principle are as described in Example 1. The rotor 8 is fitted with concentric corrugated packing. The rotor 8 has an inner diameter of 80 mm, an outer diameter of 260 mm, and a height of 100 mm. The gas-liquid split-flow liquid distributor 7 has a diameter of 83.5 mm, a height of 101 mm, and a liquid-blocking ring width of 18 mm. The gas inlet pipe 13 has a length of 12 mm and a diameter of 21 mm, arranged in two rows, with a total of 12 evenly distributed. The liquid distribution holes 14 have a diameter of 2 mm, and 18 liquid distribution holes 14 are evenly distributed on the gas-liquid split-flow liquid distributor 7. Figure 5As shown, the experiment used this apparatus to test the relationship between the constant plate height (HETP) and the gas phase kinetic energy factor (F) at rotational speeds of 900, 1200, and 1500 r / min. A mixed solution of ethanol and water was used as the experimental system. The theoretical plate height (HETP) was calculated using a plate-by-plate method based on the mole fractions of the samples at the top and bottom of the column. The difference between the inner and outer diameters was then divided by the theoretical plate height to obtain the HETP.

[0044] from Figure 5 It can be seen that the height of the plate (HETP) decreases with increasing rotational speed, and first decreases and then increases with increasing F factor, indicating that the experimental equipment has excellent mass transfer effect and high operational flexibility.

[0045] Example 3:

[0046] The principle is the same as in Example 1, and the structure is the same as in Example 2. This device was applied in total reflux distillation for hot model experiments. The reflux rate was limited to Q = 150 L / h, and the values ​​of different diameter multiples of the gas-liquid split liquid distributor 7 were used as the width of the liquid-holding ring 15 for the experiment. The theoretical plate number was monitored at different rotation speeds to obtain... Figure 6 .like Figure 6 The theoretical plate number shown increases with increasing rotational speed. At the same rotational speed, a larger width of the baffle ring 15 results in a larger theoretical plate number, demonstrating superior distributor performance. For the same theoretical plate number, a smaller baffle ring 15 requires a higher rotational speed to achieve the set theoretical plate number. Gas flows upwards through the vent pipe 13; a too-small baffle ring 15 width can cause flooding, which is detrimental to liquid distribution in the gas-liquid split-flow liquid distributor 7. When the width of the baffle ring 15 is 0.32 times and 0.4 times the cylinder diameter, the theoretical plate numbers are similar, indicating that further increasing the width of the baffle ring 15 does not have a significant effect on the hypergravity bed. A width of 0.04-0.4 times the cylinder diameter for the baffle ring 15 is more reasonable.

[0047] Example 4:

[0048] This embodiment studies the distribution performance of a gas-liquid split-flow liquid distributor using a glycerol-water system. Based on its operating conditions and structure, a cold model experiment was conducted by directly measuring the liquid output from the upper and lower distribution holes 14 of the gas-liquid split-flow liquid distributor 7 to investigate the variation of the distribution coefficient of the gas-liquid split-flow liquid distributor 7 with operating conditions. The experimental process involves the liquid in the storage tank being pressurized by a centrifugal pump, metered in a rotor flowmeter 8, and then entering the rotating gas-liquid split-flow liquid distributor 7 along the liquid inlet pipe. Under centrifugal force, the liquid moves outwards and is subsequently ejected from the distributor. The ejected liquid is collected by the upper and lower collection tanks and flows into a measuring cylinder through a hose. The distribution coefficient is the ratio of the standard deviation to the mean of the liquid flow rate within the area. The distribution coefficient value is in the range of 0-1. The closer the distribution coefficient α is to 0, the more uniform the liquid distribution and the better the distribution quality of the liquid distributor. In this experiment, under the same rotation speed N = 1000 r / min, liquid viscosity, and different liquid inlet rates and conditions, the distribution coefficient of the gas-liquid split-flow liquid distributor 7 was measured under different numbers of air inlet tubes (13) and liquid distribution holes (14).

[0049] from Figure 7 It can be seen that the distribution coefficient α increases with the increase of the liquid inlet volume, and decreases rapidly with the increase of the number of distribution holes (14), then no longer changes significantly, indicating that the distribution quality is high when the number of distribution holes (14) is within the range of 10-400. Adding more distribution holes (14) increases the workload significantly, and the effect is not obvious. Figure 8 It can be seen that the distribution coefficient α increases with the increase of liquid volume, and then decreases rapidly with the increase of the amount of liquid, then no longer changes significantly, and finally increases again, indicating that the distribution quality of the 13 air tubes is high when the number of tubes is between 5 and 40.

Claims

1. A high gravity rotating bed using a gas-liquid split flow type liquid distributor, characterized by: It includes a housing (2) and a rotating shaft (1); the housing (2) has an air outlet (4) at the upper end, an air inlet (3) at the side end, and a liquid outlet (6) at the lower end. The rotating shaft (1) passes through the housing (2) from the center of the lower end of the housing (2). The rotating shaft (1) is sealed to the housing (2) through a shaft seal (10). A rotor (8) is fixed on the rotating shaft (1). A dynamic seal (11) is provided between the upper end of the rotor (8) and the housing (2). A packing (9) is placed inside the rotor (8). A gas-liquid split-flow liquid distributor (7) is provided on the inner edge of the rotor (8). The lower end of the gas-liquid split-flow liquid distributor (7) is fixed to the base of the rotor (8). A feed pipe (5) is installed at the center of the upper end of the gas-liquid split-flow liquid distributor (7). The gas-liquid split-flow liquid distributor (7) is composed of a cylinder (12) and a liquid-blocking ring (15) at the top of the cylinder. An air intake pipe (13), a liquid distribution hole (14), and a pressure reducing platform (16) are fixed on the wall of the cylinder (12). The pressure reducing platform (16) and the air intake pipe (13) are concentrically installed on the outside of the cylinder (12), and the diameter of the pressure reducing platform (16) increases radially. The air intake pipe (13) extends into the cylinder (12).

2. A high gravity rotating bed using a gas-liquid split flow type liquid distributor according to claim 1, wherein The top of the gas-liquid split liquid distributor (7) is provided with a liquid-blocking ring (15).

3. A high gravity rotating bed using a gas-liquid split flow type liquid distributor according to claim 2, wherein The width of the liquid-blocking ring (15) is 0.04-0.4 times the diameter of the cylinder (12).

4. A high gravity rotating bed using a gas-liquid split flow type liquid distributor according to claim 1, wherein The rotor (8) is either a single layer or multiple layers arranged concentrically and vertically in series through a rotating shaft.

5. A high gravity rotating bed with gas-liquid split flow liquid distributor according to claim 1, characterized in that, The gas-liquid split-flow liquid distributor (7) includes 5-40 air intake pipes (13) and 10-400 liquid distribution holes (14); the air intake pipes (13) and liquid distribution holes (14) are evenly arranged circumferentially.

6. A high gravity rotating bed with gas-liquid split flow liquid distributor according to claim 1, characterized in that, The air intake tube (13) is a round tube, a square tube, or a conical tube.

7. A high gravity rotating bed with gas-liquid split flow liquid distributor according to claim 1, characterized in that, The liquid distribution hole (14) is circular, rectangular or triangular in shape.

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