CN103277370B - Device for adjusting fluid distribution in pipeline and method thereof - Google Patents

Abstract

The invention discloses a device and a method for adjusting fluid distribution in a pipeline. When the gas-liquid mixed fluid flows through the spiral baffle, the liquid on the pipe wall on the side with more liquid distribution moves to the side with less liquid content along the rotation direction of the spiral baffle, and the spiral baffle can make the gas The flow velocity of the liquid mixed fluid increases to promote the mixing of gas and liquid. When the flow velocity of the mixed fluid is less than 20m/s, the helix angle of the spiral baffle is greater than 45°. When the flow velocity of the mixed fluid is greater than 20m/s, the spiral baffle The helix angle is less than 45°, and the number of turns n=L/(tanα?D)-2. α is the helix angle of the spiral baffle, and D is the pipe diameter. The invention has good rectification effect on fluid, is suitable for rectification of various fluids, does not cause blockage, and prolongs the service life of various components and reactors behind the bent pipe. The pressure drop is small, reducing the loss of transmission energy. At the same time, its structure is simple, easy to install and disassemble.

Description

A device and method for adjusting fluid distribution in a pipeline

technical field

The invention relates to a device for adjusting fluid distribution, in particular to a device and method for adjusting fluid distribution in a pipeline.

Background technique

In the chemical industry, elbows are often used to change the flow direction of the fluid to complete the delivery of the fluid. However, due to the centrifugal action of the bent pipe, the components of different densities in the mixed fluid will be separated, and the flow pattern of the fluid will change greatly, forming an unstable flow. When the fluid flows through the elbow, the inner side of the elbow has a higher speed and lower pressure, while the outer side has a lower speed and higher pressure. After entering the straight pipe section, the pressure on the inside of the bend gradually increases, and the pressure on the outside gradually decreases. After passing through the elbow, the fluid needs to pass through a long section of straight pipe to restore a stable flow state. If an unstable fluid enters the reactor, it will have a great impact on the reaction. For example, in the condensed state operation of polyethylene, gas-liquid separation occurs when the gas-liquid mixture passes through the elbow connected to the inlet of the fluidized bed reactor. After entering the reactor, it will cause local liquid content to be low and form hot spots, which will eventually lead to polymer agglomeration. phenomenon occurs. At the same time, the unsteady flow of fluid repeatedly washes the reactor asymmetrically, which seriously affects the life of the reactor. However, due to space constraints in actual production, it is impossible to increase the length of the straight pipe section without limit to restore the fluid to a steady flow state, so it is necessary to invent a device that can well adjust the fluid flow pattern to reduce the length of the straight pipe section and avoid Effects of unstable fluids on products and reactors.

Patent CN 102155477 A proposes a rectifier for adjusting the flow velocity distribution of an elbow. The main structure of the rectifier is a circular plate and holes arranged along its radial direction. The holes are distributed asymmetrically, that is, the diameter close to the outside of the matching elbow is smaller than the diameter close to the inside of the matching elbow. This kind of rectifier designs the hole size distribution according to the distribution of the fluid through the elbow, which can play a certain rectification effect. However, since there are many openings, this will cause a large pressure drop and increase the energy consumption of fluid transportation.

Patent CN 102435253 A proposes a flow regulator for fluid transmission pipelines. The invention adopts "guide vane assembly + rectifier body + guide vane assembly", and the main body of the rectifier is composed of porous medium material. This kind of adjuster has a complex structure and is not suitable for the situation where a small amount of solid particles are entrained in the fluid, and it is easy to cause blockage.

The fluid mixing rectifier proposed in the patent US 2011/0174408 A1 is composed of a deflector with openings. Although the rectifier has a good rectification effect on gas, it also has a large pressure drop, which is not conducive to fluid transportation.

In order to make the gas-liquid mixture quickly develop into a steady flow after the bend and shorten the necessary straight pipe length, it is necessary to invent a device that can effectively adjust the flow pattern of the gas-liquid, so that the gas-liquid mixture can be evenly distributed after entering the subsequent reactor . Reduces asymmetric flushing of reactors by unstable fluids without causing large pressure drops and solid plugging.

Contents of the invention

The object of the present invention is to provide a device and method for adjusting fluid distribution in the pipeline in order to overcome the shortcomings of the current gas-liquid rectifier.

The device for adjusting the gas-liquid distribution in the pipeline is: a section of spiral baffle is arranged on the inner wall of the pipeline, the starting point of the spiral baffle is located on the tube wall on the side with high liquid content, and the end point is located on the tube wall on the side with low liquid content; The helix angle α of the spiral baffle is 1°～90°, the width W of the spiral baffle is 0.01D～0.5D, where D is the diameter of the pipeline, and the number of helical turns of the spiral baffle is 0.1～100 circles. The included angle between the spiral baffle and the pipe wall is 1°-90°.

The helix angle α of the spiral baffle is preferably 5°-85°. The width W of the spiral baffle is preferably 0.05D to 0.3D. The number of helical turns of the helical baffle is preferably 0.5 to 3 turns. The angle between the spiral baffle and the pipe wall is preferably 30°-60°.

The method of adjusting the gas-liquid distribution in the pipeline is: when the gas-liquid mixed fluid flows through the spiral baffle, the liquid on the side of the pipe wall with more liquid distribution moves to the side with less liquid content along the direction of rotation of the spiral baffle At the same time, the spiral baffle can increase the flow velocity of the gas-liquid mixed fluid and promote the mixing of gas and liquid. When the flow velocity of the mixed fluid is less than 20m/s, the helix angle of the spiral baffle is greater than 45°. When the flow velocity of the mixed fluid is greater than At 20m/s, the helix angle of the helical baffle is less than 45°, the number of turns n=L/(tanα·D)-2, α is the helix angle of the helical baffle, and D is the pipe diameter. When the liquid mole fraction is less than 10%, the angle between the spiral baffle and the tube wall is greater than 30°; when the liquid mole fraction is greater than 10%, the angle between the spiral baffle and the tube wall is less than 30° °.

The invention has a simple structure, is easy to install and disassemble, is suitable for rectification of various gas-liquid mixed fluids, and will not cause blockage. After experimental tests, the spiral plate rectifier has a good rectification effect on the fluid, and the pressure drop generated by the fluid passing through the device is small, thereby reducing the loss of transmission energy. In addition, it can also improve the life of various components and reactors behind the pipeline.

Description of drawings

Fig. 1 is a structural schematic diagram of a device for adjusting fluid distribution in a horizontal pipeline, and the arrows indicate the flow direction of the fluid;

Fig. 2 is a structural schematic diagram of a device for adjusting fluid distribution in a vertical pipeline, and the arrow indicates the flow direction of the fluid;

Fig. 3 is a structural schematic diagram of the device for adjusting fluid distribution in the elbow, and the arrows indicate the flow direction of the fluid.

Detailed ways

The device for adjusting the gas-liquid distribution in the pipeline is: a section of spiral baffle 2 is arranged on the inner wall of the pipeline 1, the starting point of the spiral baffle is located on the tube wall on the side with high liquid content, and the end point is located on the tube wall on the side with low liquid content; The helix angle α of the spiral baffle is 1° to 90°, the width W of the spiral baffle is 0.01D to 0.5D, wherein D is the diameter of the pipeline, and the number of helical turns of the spiral baffle is 0.1 to 100 The angle between the spiral baffle and the pipe wall is 1°～90°.

The helix angle α of the spiral baffle 2 is preferably 5°-85°. The width W of the spiral baffle 2 is preferably 0.05D˜0.3D. The number of helical turns of the helical baffle plate 2 is preferably 0.5-3 turns. The angle between the spiral baffle 2 and the pipe wall is preferably 30°-60°.

The method of adjusting the gas-liquid distribution in the pipeline is: when the gas-liquid mixed fluid flows through the spiral baffle 2, the liquid on the pipe wall on the side with more liquid distribution moves to the side with less liquid content along the rotation direction of the spiral baffle. At the same time, the spiral baffle can increase the flow velocity of the gas-liquid mixed fluid and promote the mixing of gas and liquid. When the flow velocity of the mixed fluid is less than 20m/s, the helix angle of the spiral baffle is greater than 45°. When the flow velocity of the mixed fluid When it is greater than 20m/s, the helix angle of the helical baffle is less than 45°, the number of turns n=L/(tanα•D)-2, α is the helix angle of the helical baffle, and D is the diameter of the pipe. When the liquid mole fraction is less than 10%, the angle between the spiral baffle and the tube wall is greater than 30°; when the liquid mole fraction is greater than 10%, the angle between the spiral baffle and the tube wall is less than 30° °.

The spiral plate proposed by the present invention can be manufactured using any known material, but it is necessary to select a matching material according to specific process conditions. In addition, the spiral plate can be connected to the pipeline by common fixing methods such as welding and riveting, and the preferred solution is to connect to the pipeline by welding. The rectifier provided by the present invention is suitable for flow pattern adjustment of gas-liquid two-phase flow and gas-liquid-solid three-phase flow with solids in horizontal pipes, vertical pipes and inclined pipes, and is especially suitable for the flow pattern adjustment in the pipeline after passing through the bent pipe. Flow pattern adjustment of gas-liquid two-phase flow and gas-liquid-solid three-phase flow with solids.

Example 1:

As shown in Figure 1, a spiral plate is installed in a horizontal pipeline to adjust the gas-liquid distribution in the pipeline. Among them, the diameter of the pipe is 882 mm and the length is 2000 mm; the starting point of the spiral plate is located at the lower part of the horizontal pipe where the liquid accumulates; the angle α between the line segment representing the spiral plate and the pipe diameter is 25°; the width W of the spiral plate is 50 mm , the angle θ between the surface where it is located and the tube wall surface is 45°; the spiral plate spirals forward counterclockwise relative to the fluid flow direction, and the number of rotations is 2.5. The experiment was carried out with air and water as the simulated medium, the gas flow rate was 12 m/s, and the mole fraction of water was 8%. When the spiral plate is not installed, the pressure drop between the inlet and outlet of the pipeline is 1060 Pa, and the variation coefficient of liquid content on the section of the pipeline outlet is 16.7%; after the spiral plate is installed, the pressure drop between the inlet and outlet of the pipeline is 1090 Pa, The coefficient of variation of the liquid content on the pipe outlet section is 5.8%. Among them, the coefficient of variation is defined as the ratio of the standard deviation of the liquid content on the outlet section to the average value, reflecting the degree of dispersion of the liquid content distribution on the section. The larger the coefficient of variation, the more uneven the distribution of liquid content on the section; the smaller the coefficient of variation, the more uniform the distribution of liquid content. The experimental results show that the spiral plate can greatly improve the uniformity of gas-liquid distribution in the pipeline while slightly increasing the pressure drop at the inlet and outlet of the horizontal pipeline.

Example 2:

As shown in Figure 2, a spiral plate is installed in the vertical pipeline to adjust the gas-liquid distribution in the pipeline. Among them, the diameter of the pipe is 882 mm, and the length is 2000 mm; the starting point of the spiral plate is located on the side of the pipe wall where the liquid accumulates; the angle α between the line segment representing the spiral plate and the pipe diameter is 30°; the width W of the spiral plate is 50 mm, the angle θ between the surface where it is located and the pipe wall surface is 60°; the spiral plate spirals forward clockwise relative to the direction of fluid flow, and the number of rotations is 1.5. The experiment was carried out with air and water as the simulated medium, the gas flow rate was 12 m/s, and the mole fraction of water was 8%. When the spiral plate is not installed, the pressure drop between the inlet and outlet of the pipeline is 1140 Pa, and the variation coefficient of liquid content on the section of the pipeline outlet is 16.3%; after the spiral plate is installed, the pressure drop between the inlet and outlet of the pipeline is 1165 Pa, The coefficient of variation of the liquid content on the pipe outlet section is 4.3%. The experimental results show that the spiral plate can greatly improve the uniformity of gas-liquid distribution in the pipeline while slightly increasing the pressure drop at the inlet and outlet of the vertical pipeline.

Example 3:

As shown in Figure 3, a spiral plate is installed in the vertical pipeline behind the elbow to adjust the gas-liquid distribution in the pipeline. Among them, the pipe diameter is 882 mm, the length of the horizontal pipe is 1000 mm, and the length of the vertical pipe is 2000 mm mm, the elbow is a standard 90° elbow. The starting point of the spiral plate is located outside the vertical pipe where the liquid gathers downstream of the elbow; the angle α between the line segment of the spiral plate and the pipe diameter is 45°; the width W of the spiral plate is 45 mm, and the distance between the surface where it is located and the pipe wall surface The included angle θ is 30°; the spiral plate spirals forward clockwise relative to the fluid flow direction, and the number of rotations is 1.5. The experiment was carried out with air and water as the simulated medium, the gas flow rate was 14 m/s, and the mole fraction of water was 10%. When the spiral plate is not installed, the pressure drop between the inlet and outlet of the pipeline is 1725 Pa, and the variation coefficient of liquid content on the section of the pipeline outlet is 16.5%; after the spiral plate is installed, the pressure drop between the inlet and outlet of the pipeline is 1760 Pa, The coefficient of variation of the liquid content on the pipe outlet section is 6.2%. The experimental results show that the spiral plate can greatly improve the uniformity of gas-liquid distribution in the vertical pipeline after the bend while slightly increasing the pressure drop at the inlet and outlet of the pipeline.

Claims (5)

1. gas-liquid location mode in an adjustment pipeline, it is characterized in that: when gas-liquid mixture fluid flows through spiral baffle (2) in the device of gas-liquid distribution in adjustment pipeline, the sense of rotation of the liquid runs down spiral baffle on the side tube wall that liquid distribution is many moves to the few side of content liquid, spiral baffle can make the flow velocity of gas-liquid mixture fluid increase simultaneously, promote the mixing of gas-liquid, when the flow velocity of fluid-mixing is less than 20m/s, the spiral angle of spiral baffle is greater than 45 °, when the flow velocity of fluid-mixing is greater than 20m/s, the spiral angle of spiral baffle is less than 45 °, number of turns n=L/(tan α D)-2, α is the helix angle of spiral baffle, D is pipe diameter, L is duct length, when liquid mole fraction content is less than 10%, angle between spiral baffle and tube wall face is greater than 30 °, when liquid mole fraction content is greater than 10%, angle between spiral baffle and tube wall face is less than 30 °, in described adjustment pipeline, the device of gas-liquid distribution is: on pipeline (1) inwall, arrange one section of spiral baffle (2), the starting point of spiral baffle is positioned at the high side tube wall of content liquid, and terminal is positioned at the low side tube wall of content liquid, the pitch angle alpha will of described spiral baffle is 1 ° ~ 90 °, and the width W of spiral baffle is 0.01D ~ 0.5D, and wherein D is the diameter of pipeline, and the spiral number of turns of spiral baffle is 0.1 ~ 100 circle, and the angle between spiral baffle and tube wall face is 1 ° ~ 90 °.

2. gas-liquid location mode in one adjustment pipeline according to claim 1, is characterized in that: the pitch angle alpha will of described spiral baffle (2) is 5 ° ~ 85 °.

3. gas-liquid location mode in one adjustment pipeline according to claim 1, is characterized in that: the width W of described spiral baffle (2) is 0.05D ~ 0.3D.

4. gas-liquid location mode in one adjustment pipeline according to claim 1, is characterized in that: the spiral number of turns of described spiral baffle (2) is 0.5 ~ 3 circle.

5. gas-liquid location mode in one adjustment pipeline according to claim 1, is characterized in that: the angle between described spiral baffle and tube wall face is 30 ° ~ 60 °.