An industrial design and optimization method applied to gas-liquid distributor of packed bed

Abstract

The application provides an industrial design and optimization method applied to a gas-liquid distributor of a packed bed. The method combines empirical engineering calculation and computational fluid dynamics method, and is based on engineering design of the gas-liquid distributor. The method increases closed-loop optimization design of a single gas-liquid distributor and the whole packed bed, and obtains the gas-liquid distributor center tube diameter and the number of the gas-liquid distributor which meet the engineering design requirements. The optimization adjustment period is short, and the design cost is low.

Description

Technical Field

[0001] This invention relates to the field of multiphase packed bed reactor design technology, and in particular to an industrial design and optimization method for a gas-liquid distributor applied to a packed bed. Background Technology

[0002] The gas-liquid distributor is an important internal component in a packed bed gas-liquid-solid three-phase reactor. It ensures that the liquid can be evenly distributed throughout the entire reactor cross-section, thereby ensuring that the packed catalyst particles can uniformly contact the reactants and achieve the designed reaction performance.

[0003] Currently, the design methods for gas-liquid distributors largely rely on engineering calculations using empirical parameters and formulas from design manuals and relevant specifications. The accuracy of gas-liquid distributor engineering designs heavily depends on empirical correlations. These empirical parameters and formulas are derived from extensive engineering practice and offer advantages such as simple and convenient calculation processes. However, if certain parameter selections lack strong justification, or if empirical correlations are not applicable to gas-liquid-solid three-phase systems with unique characteristics such as high viscosity, high gas-liquid ratio, or the presence of contaminating particles, the uniform gas-liquid distribution process of the gas-liquid distributor cannot be guaranteed. Furthermore, experimental methods for designing gas-liquid distributors can provide a direct view of the gas-liquid distribution near the distributor. However, due to limitations in experimental setup and measuring instruments, experimental studies of gas-liquid distributors can only obtain gas-liquid distribution data near the outlets of one or several distributors. Moreover, the accuracy of gas-liquid distribution data for each cross-section is not high due to limitations in experimental measurement methods. For multivariate design processes, the operating and time costs of experiments are relatively high, resulting in long design cycles and high costs. Neither of the above methods can achieve the gas-liquid distribution effect of the gas-liquid distributor on the packed bed reactor where it is installed. Therefore, the flow and gas-liquid distribution inside the packed bed reactor are rarely considered in the design.

[0004] In packed bed reactors and their gas-liquid distributors, gas and liquid are the main carriers of matter and energy transfer. The dynamic characteristics of the reactor and its gas-liquid distributor directly affect the gas-liquid mixing and distribution process at the outlet of the gas-liquid distributor and within the reactor, thus restricting the gas-liquid distribution effect of the gas-liquid distributor.

[0005] Therefore, it is of great significance to develop an industrial design and optimization method for gas-liquid distributors applied to packed beds that can accurately and efficiently simulate the flow field and liquid distribution inside the gas-liquid distributor. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides an industrial design and optimization method for gas-liquid distributors applied to packed beds. It combines experience-based engineering calculations and computational fluid dynamics (CFD) methods, and optimizes the design from both the individual gas-liquid distributor and the entire packed bed. This results in a gas-liquid distributor with a central cylinder diameter and number that meet the engineering design requirements. The industrial design and optimization method has the advantages of short optimization design cycle and low cost.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides an industrial design and optimization method for a gas-liquid distributor applied to a packed bed, the industrial design and optimization method comprising the following steps:

[0009] (1) Assuming the minimum diameter and number of the gas-liquid distributor's central cylinder, the opening ratio of the distribution plate, gas-liquid velocity, gas-liquid Re number and pressure drop are obtained through engineering design calculations based on the industrial packed bed diameter and gas-liquid flow rate.

[0010] Determine whether the assumed minimum diameter and number of the gas-liquid distributor's central cylinders meet the range of distribution plate opening ratio, gas-liquid velocity, gas-liquid Reynolds number, and pressure drop in industrial design; if not, repeat this step; if yes, proceed to the next step.

[0011] (2) Based on the minimum diameter of the gas-liquid distributor center cylinder and the geometric dimensions of a single gas-liquid distributor described in step (1), the gas-liquid distribution of a single gas-liquid distributor is simulated and calculated using computational fluid dynamics. The spray area of ​​a single gas-liquid distributor and the number of gas-liquid distributors described in step (1) are used to verify whether the spray area of ​​the gas-liquid distributor covers the entire cross-section of the packed bed.

[0012] Determine whether the spray area of ​​the gas-liquid distributor can cover the entire cross-section of the packed bed. If not, repeat this step; if yes, proceed to the next step.

[0013] (3) Simplify a single gas-liquid distributor into a circular hole, use computational fluid dynamics to simulate and calculate the gas-liquid distribution of the packed bed, and determine whether the pressure drop of the packed bed and the uniformity of the gas-liquid distribution meet the industrial design requirements; if not, repeat steps (1) to (3); if yes, the industrial design optimization ends, and the diameter and number of gas-liquid distributor center cylinders are obtained.

[0014] The industrial design and optimization method for gas-liquid distributors applied to packed beds described in this invention first assumes a minimum diameter of the central cylinder and the number of gas-liquid distributors. Then, combining this with the diameter of the industrial packed bed and the gas-liquid flow rate, engineering design calculations are performed to obtain the distribution plate opening ratio, gas-liquid velocity, gas-liquid Reynolds number (Re) number, and pressure drop. It then determines whether the assumed minimum diameter and number of the central cylinder of the gas-liquid distributor meet the ranges for distribution plate opening ratio, gas-liquid velocity, gas-liquid Reynolds number, and pressure drop in industrial design. Optimization design is then performed to obtain a minimum diameter and number of the central cylinder of the gas-liquid distributor that meet the conditions. Finally, based on the optimized minimum diameter of the central cylinder of the gas-liquid distributor and the geometric dimensions of a single gas-liquid distributor, the following method is adopted: Computational fluid dynamics (CFD) methods are used to simulate and calculate the gas-liquid distribution of a single gas-liquid distributor. Then, it is determined whether the spray area and number of distributors can cover the entire cross-section of the packed bed, thus deriving the diameter of the central cylinder of the gas-liquid distributor that conforms to the internal gas-liquid distribution of the single distributor. Finally, by simplifying the single gas-liquid distributor to a circular orifice, CFD methods are used to simulate and calculate the gas-liquid distribution of the packed bed, determining whether the bed pressure drop and gas-liquid distribution uniformity meet industrial design requirements. This leads to the determination of the diameter and number of central cylinders of the gas-liquid distributors that conform to the overall gas-liquid distribution of the packed bed. This achieves multi-scale, multi-angle evaluation and optimization of the gas-liquid distributor, making it suitable for engineering applications. The industrial design and optimization method described in this invention combines the advantages of engineering design and CFD simulation, forming a closed-loop optimization design. This results in a short optimization adjustment cycle and low design cost, with broad prospects for large-scale application.

[0015] In this invention, the evaluation criteria for the range of distribution plate opening ratio, gas-liquid velocity, gas-liquid Re number and pressure drop in the industrial design described in step (1), whether the spray area of ​​the gas-liquid distributor in step (2) can cover the entire cross-section of the packed bed, and whether the bed pressure drop and gas-liquid distribution uniformity of the packed bed in step (3) meet the industrial design requirements can be customized according to the properties of the gas and liquid, the properties of the packing material in the packed bed, the power system requirements, energy consumption requirements, radial and axial temperature distribution requirements, etc., to meet the needs of actual engineering applications.

[0016] Preferably, the formula for calculating the opening ratio of the central cylinder distribution plate in step (1) is:

[0017]

[0018] Where: n - the number of gas-liquid distributors;

[0019] d0 - Minimum diameter of the central cylinder of the gas-liquid distributor, in mm;

[0020] D - Diameter of the packed bed, in meters;

[0021] Preferably, the gas-liquid velocity includes both gas velocity and liquid velocity.

[0022] Preferably, the formula for calculating the gas velocity is:

[0023]

[0024] Where: q gas -Gas flow rate, m 3 / h.

[0025] Preferably, the formula for calculating the liquid velocity is:

[0026]

[0027] Where: q oil - Liquid flow rate, m 3 / h.

[0028] Preferably, the gas-liquid Re number includes the gas Re number and the liquid Re number.

[0029] Preferably, the formula for calculating the Reynolds number of the gas is:

[0030]

[0031] Where: ρ gas - Density of the gas, kg / m³ 3 ;ν gas It is the gas viscosity, mPa·s.

[0032] Preferably, the formula for calculating the Re number of the liquid is:

[0033]

[0034] Where: ρ oil - The density of the liquid, kg / m³ 3 ;ν oil It is the viscosity of the liquid, in mPa·s.

[0035] Preferably, the gas-liquid distributor includes a bubble-type gas-liquid distributor, an overflow-type gas-liquid distributor, a jet-type distributor, a venturi-type gas-liquid distributor, and a gas-liquid distributor with a liquid-breaking plate.

[0036] Preferably, the pressure drop calculation formula for the blister-type gas-liquid distributor is as follows:

[0037] lg(Δp')=1.509q oil -0.088 +0.035U gas ;

[0038] Δp dist =9.807×10 3 Δp';

[0039] Where: Δp dist - Pressure drop of the gas-liquid distributor.

[0040] Preferably, the pressure drop calculation formula for the overflow-type gas-liquid distributor is:

[0041]

[0042]

[0043] Where: ξ - pressure drop resistance coefficient of the gas-liquid distributor.

[0044] Preferably, the pressure drop calculation formula for the jet-type distributor is:

[0045] lg(Δp')=1.0485U gas 0.366 +2.6483U oil 0.549 ;

[0046] Δp dist =1.3332×10 2 Δp';

[0047] Preferably, the pressure drop calculation formula for the Venturi-type gas-liquid distributor is as follows:

[0048] Δp dist =1.706×10 -7 Re oil 0.9623 Re gas 1.467 .

[0049] Preferably, the pressure drop calculation formula for the gas-liquid distributor with liquid-breaking plate is:

[0050]

[0051] A typical single gas-liquid distributor consists of a central cylinder (of equal or varying diameter), a bubble cap, and slots on the bubble cap. Gas and liquid premix in the upper part to the lower part of the upper head. Gas enters the distributor through the bottom of the bubble cap and the bubble cap slots. Some liquid is entrained to the top of the distributor along with the gas, deflected into the central cylinder, and then exits at the central cylinder outlet to enter the reactor bed. Some liquid that fails to follow the gas forms a stagnant liquid layer at the bottom of the distribution plate.

[0052] Preferably, the geometric dimensions of the single gas-liquid distributor in step (2) include the diameter d0 of the central cylinder, the first height h1 of the central cylinder, the second height h3 of the central cylinder, the diameter d1 of the bubble cap, the height h4 of the bubble cap, the distance h2 between the top of the bubble cap and the top of the central cylinder, the number of slits in the bubble cap, the height h5 of the circumferential slits around the bubble cap, and the static liquid level height h6.

[0053] The geometric dimensions of the single gas-liquid distributor described in this invention are given based on the type of gas-liquid distributor and engineering experience, wherein the types of gas-liquid distributors include suction-type gas-liquid distributors, overflow-type gas-liquid distributors and mixing-type gas-liquid distributors.

[0054] Preferably, step (2) of simulating the gas-liquid distribution of a single gas-liquid distributor using computational fluid dynamics includes:

[0055] (A) Based on the geometric dimensions of the individual gas-liquid distributor, a three-dimensional geometric model of the individual gas-liquid distributor is established using Solidworks;

[0056] (B) Perform topological analysis on the three-dimensional geometric model of the single gas-liquid distributor, and use a hybrid meshing scheme that combines structured and unstructured meshes to mesh the computational domain of the single gas-liquid distributor.

[0057] (C) Define the computational domain boundary for a single gas-liquid distributor, select a 3D implicit solver and an Euler-Euler multiphase model, and couple the population equilibrium model;

[0058] (D) Initialize the computational domain of a single gas-liquid distributor, perform iterative calculations, and stop the loop when the residuals meet the calculation requirements;

[0059] (E) Export the numerical simulation results of the flow of a single gas-liquid distributor, obtain the coefficient of variation of the liquid velocity at the outlet of the computational domain of a single gas-liquid distributor, and calculate the equivalent spray radius.

[0060] Preferably, the geometric dimensions of the single gas-liquid distributor in step (A) include:

[0061] d1=(1.1~5)d0, h1=(2~20)d0, h2=(0.1~5)d0, h3=(0.1~5)d0, h4=(2~20)d0,

[0062] h5=(0.1~5)d0, h6=(0.1~10)d0.

[0063] The present invention (B) imports the three-dimensional geometric model of a single gas-liquid distributor into the ICEMCFD software for topology analysis.

[0064] Preferably, during the mesh generation process described in step (B), mesh densification and irrelevance verification are performed on the wall surface, openings, and other locations of a single gas-liquid distributor.

[0065] The mesh refinement and independence verification described in this invention can be performed using methods well-known to those skilled in the art. Refining the mesh at locations such as the wall and openings of a single gas-liquid distributor ensures the stability and computational accuracy of the simulation.

[0066] Preferably, in step (C), the inlet of the computational domain in the computational domain boundary of the single gas-liquid distributor is a given gas-liquid flow rate: q gas,1 =q gas / n, q oil,1 =q oil / n; the circumferential direction is the wall, and the outlet is the outflow boundary with zero static pressure.

[0067] Preferably, the formula for calculating the coefficient of variation (CV) of the outlet liquid velocity in the computational domain of the single gas-liquid distributor in step (E) is as follows:

[0068]

[0069] Where: N - number of grid cells at the exit section;

[0070] U oil - Local liquid velocity at grid points, m / s;

[0071] - Average liquid velocity at the outlet section, m / s;

[0072] Preferably, the equivalent spray radius R in step (E) c The calculation formula is:

[0073]

[0074] Wherein: S c -Spraying area, m 2 .

[0075] Preferably, the geometry of a single gas-liquid distributor is evaluated and optimized based on the liquid velocity variation coefficient and the static liquid level height.

[0076] Since the geometric dimensions of the single gas-liquid distributor described in this invention are given based on the type of gas-liquid distributor and engineering experience, optimization and adjustment are required in this step.

[0077] Preferably, step (3) involves using computational fluid dynamics to simulate and calculate the gas-liquid distribution of the entire packed bed, including:

[0078] (A') Based on the minimum diameter and number of the central cylinder of a single gas-liquid distributor and the diameter of the packed bed, a three-dimensional geometric model of the entire packed bed and its gas-liquid distributor is established using Solidworks, wherein the particle gradation in the packed bed is divided into m regions.

[0079] (B') An unstructured meshing scheme is adopted to mesh the entire computational domain of the filled bed;

[0080] (C') Set the computational domain boundary for the entire packed bed and select the Euler-Euler multiphase model within the porous medium;

[0081] (D') Initialize the computational domain of the entire packed bed, perform iterative calculations, and stop the loop when the residuals meet the calculation requirements;

[0082] (E') Export the numerical simulation results of gas-liquid flow in the entire packed bed and analyze its radial and axial gas-liquid distribution and its uniformity.

[0083] The present invention does not limit the method of dividing the particle gradation in the packed bed into m regions in step (A'), and those skilled in the art can divide it according to the actual engineering needs.

[0084] In step (B') of this invention, the three-dimensional geometric model of the entire packed bed and its gas-liquid distributor is imported into the ICEMCFD software, and an unstructured mesh generation scheme is used to generate a mesh within the computational domain of the entire packed bed reactor.

[0085] Preferably, in step (C'), the n orifice inlets in the computational domain boundary of the entire packed bed are given gas-liquid flow rates: q gas,1 =q gas / n, q oil,1 =q oil / n; the circumferential direction is the wall, and the outlet is the outflow boundary with zero static pressure.

[0086] As a preferred technical solution of the present invention, the industrial design and optimization method includes the following steps:

[0087] (1) Assuming the minimum diameter and number of the gas-liquid distributor's central cylinder, the opening ratio of the distribution plate, gas-liquid velocity, gas-liquid Re number and pressure drop are obtained through engineering design calculations based on the industrial packed bed diameter and gas-liquid flow rate.

[0088] The formula for calculating the opening ratio of the central cylinder distribution plate is:

[0089]

[0090] Where: n - the number of gas-liquid distributors;

[0091] d0 - Minimum diameter of the central cylinder of the gas-liquid distributor, in mm;

[0092] D - Diameter of the packed bed, in meters;

[0093] The gas-liquid velocity includes both gas velocity and liquid velocity;

[0094] The formula for calculating the gas velocity is:

[0095]

[0096] Where: q gas -Gas flow rate, m 3 / h;

[0097] The formula for calculating the liquid velocity is:

[0098]

[0099] Where: q oil - Liquid flow rate, m 3 / h;

[0100] The gas-liquid Re number includes the gas Re number and the liquid Re number;

[0101] The formula for calculating the Reynolds number of the gas is:

[0102]

[0103] Where: ρ gas - Density of the gas, kg / m³ 3 ;

[0104] ν gas -Gas viscosity, mPa·s;

[0105] The formula for calculating the Re number of the liquid is:

[0106]

[0107] Where: ρ oil - The density of the liquid, kg / m³ 3 ;

[0108] ν oil - is the liquid viscosity, mPa·s;

[0109] The gas-liquid distributor includes a bubble-type gas-liquid distributor, an overflow-type gas-liquid distributor, a jet-type distributor, a venturi-type gas-liquid distributor, and a gas-liquid distributor with a liquid-breaking plate.

[0110] The pressure drop calculation formula for the bubble-type gas-liquid distributor is as follows:

[0111] lg(Δp')=1.509q oil -0.088 +0.035U gas ;

[0112] Δp dist =9.807×10 3 Δp';

[0113] Where: Δp dist - Pressure drop of the gas-liquid distributor;

[0114] The pressure drop calculation formula for the overflow-type gas-liquid distributor is as follows:

[0115]

[0116]

[0117] Where: ξ - resistance coefficient of the gas-liquid distributor;

[0118] The pressure drop calculation formula for the jet-type distributor is as follows:

[0119] lg(Δp')=1.0485U gas 0.366 +2.6483U oil 0.549 ;

[0120] Δp dist =1.3332×10 2 Δp';

[0121] The pressure drop calculation formula for the Venturi-type gas-liquid distributor is as follows:

[0122] Δp dist =1.706×10 -7 Re oil 0.9623 Re gas 1.467 ;

[0123] The pressure drop calculation formula for the gas-liquid distributor with liquid breaking plate is as follows:

[0124]

[0125] Determine whether the assumed minimum diameter and number of the gas-liquid distributor's central cylinders meet the range of distribution plate opening ratio, gas-liquid velocity, gas-liquid Reynolds number, and pressure drop in industrial design; if not, repeat this step; if yes, proceed to the next step.

[0126] (2) Based on the minimum diameter of the gas-liquid distributor center cylinder and the geometric dimensions of a single gas-liquid distributor described in step (1), the gas-liquid distribution of a single gas-liquid distributor is simulated and calculated using computational fluid dynamics. The spray area of ​​a single gas-liquid distributor and the number of gas-liquid distributors described in step (1) are used to verify whether the spray area of ​​the gas-liquid distributor covers the entire cross-section of the packed bed.

[0127] The steps for simulating the gas-liquid distribution of a single gas-liquid distributor using computational fluid dynamics methods include:

[0128] (A) Based on the geometric dimensions of the individual gas-liquid distributor, a three-dimensional geometric model of the individual gas-liquid distributor is established using Solidworks;

[0129] The geometric dimensions of a single gas-liquid distributor include the central cylinder diameter d0, the first central cylinder height h1, the second central cylinder height h3, the bubble cap diameter d1, the bubble cap height h4, the distance between the top of the bubble cap and the top of the central cylinder h2, the number of bubble cap slots, the height of the circumferential slots around the bubble cap h5, and the static liquid level height h6; the geometric dimension relationships of a single gas-liquid distributor include: d1 = (1.1~5)d0, h1 = (2~20)d0, h2 = (0.1~5)d0, h3 = (0.1~5)d0, h4 = (2~20)d0, h5 = (0.1~5)d0, h6 = (0.1~10)d0;

[0130] (B) Perform topological analysis on the three-dimensional geometric model of the single gas-liquid distributor, and use a hybrid mesh generation scheme that combines structured and unstructured meshes to generate a mesh within the computational domain of the single gas-liquid distributor; during the mesh generation process, perform mesh refinement and independence verification at locations such as the wall surface and openings of the single gas-liquid distributor.

[0131] (C) Define the computational domain boundary for a single gas-liquid distributor, select a 3D implicit solver and an Euler-Euler multiphase model, and couple a population equilibrium model; the inlet of the computational domain boundary for the single gas-liquid distributor is a given gas-liquid flow rate: q gas,1 =q gas / n, q oil,1 =q oil / n; The circumferential direction is the wall, and the outlet is the outflow boundary with zero static pressure;

[0132] (D) Initialize the computational domain of a single gas-liquid distributor, perform iterative calculations, and stop the loop when the residuals meet the calculation requirements;

[0133] (E) Export the numerical simulation results of the flow of a single gas-liquid distributor, obtain the coefficient of variation of the liquid velocity at the outlet of the computational domain of a single gas-liquid distributor, and calculate the equivalent spray radius;

[0134] The formula for calculating the coefficient of variation (CV) of the outlet liquid velocity in the computational domain of a single gas-liquid distributor is as follows:

[0135]

[0136] Where: N - number of grid cells at the exit section;

[0137] U oil - Local liquid velocity at grid points, m / s;

[0138] - Average liquid velocity at the outlet section, m / s.

[0139] The equivalent spray radius R in step (E) c The calculation formula is:

[0140]

[0141] Wherein: S c -Spray area (m) 2 ;

[0142] Determine whether the spray area of ​​the gas-liquid distributor can cover the entire cross-section of the packed bed. If not, repeat this step; if yes, proceed to the next step.

[0143] (3) Simplify a single gas-liquid distributor into a circular hole, use computational fluid dynamics to simulate and calculate the gas-liquid distribution of the packed bed, and determine whether the pressure drop of the packed bed and the uniformity of the gas-liquid distribution meet the industrial design requirements; if not, repeat steps (1) to (3); if yes, the industrial design optimization ends, and the diameter and number of the gas-liquid distributor center cylinder are obtained.

[0144] The steps of simulating the gas-liquid distribution of the entire packed bed using computational fluid dynamics include:

[0145] (A') Based on the minimum diameter and number of the central cylinder of a single gas-liquid distributor and the diameter of the packed bed, a three-dimensional geometric model of the entire packed bed and its gas-liquid distributor is established using Solidworks, wherein the particle gradation in the packed bed is divided into m regions.

[0146] (B') An unstructured meshing scheme is adopted to mesh the entire computational domain of the filled bed;

[0147] (C') Define the computational domain boundary for the entire packed bed, and select the Euler-Euler multiphase model within the porous medium; the n inlet holes in the computational domain boundary of the entire packed bed represent a given gas-liquid flow rate: q gas,1 =q gas / n, q oil,1 =q oil / n; The circumferential direction is the wall, and the outlet is the outflow boundary with zero static pressure;

[0148] (D') Initialize the computational domain of the entire packed bed, perform iterative calculations, and stop the loop when the residuals meet the calculation requirements;

[0149] (E') Export the numerical simulation results of gas-liquid flow in the entire packed bed and analyze its radial and axial gas-liquid distribution and its uniformity.

[0150] Compared with the prior art, the present invention has at least the following beneficial effects:

[0151] (1) The present invention provides an industrial design and optimization method for a gas-liquid distributor applied to a packed bed. It combines the geometric optimization of a single gas-liquid distributor with the engineering design requirements of the entire packed bed to evaluate the gas-liquid distributor from multiple scales and angles, making its design more accurate and comprehensive.

[0152] (2) The present invention provides an industrial design and optimization method for a gas-liquid distributor applied to a packed bed, which utilizes engineering design and computational fluid dynamics simulation to form a closed-loop optimization design, with a short optimization adjustment cycle and low design cost. Attached Figure Description

[0153] Figure 1 This is a flowchart illustrating an industrial design and optimization method for a gas-liquid distributor applied to a packed bed, provided by the present invention.

[0154] Figure 2 This is a schematic diagram showing the positions of the packed bed and the gas-liquid distributor in a specific embodiment of the present invention.

[0155] Figure 3 This is a schematic diagram of the composition of a single gas-liquid distributor in a specific embodiment of the present invention.

[0156] Figure 4 This is a schematic diagram of a three-dimensional geometric model of a single gas-liquid distributor in a specific embodiment of the present invention.

[0157] Figure 5 This is a schematic diagram of the geometric dimensions and computational domain of a single gas-liquid distributor in a specific embodiment of the present invention.

[0158] Figure 6 This is a graph showing the result of calculating the coefficient of variation of the outlet liquid velocity of a single gas-liquid distributor in a specific embodiment of the present invention.

[0159] Figure 7 This is a diagram showing the equivalent spray radius of a single gas-liquid distributor in a specific embodiment of the present invention.

[0160] Figure 8 This is a graph showing the pressure drop of a single gas-liquid distributor in a specific embodiment of the present invention.

[0161] Figure 9 This is a schematic diagram of the structure of the filling bed in a specific embodiment of the present invention.

[0162] Figure 10 This is a schematic diagram of a three-dimensional geometric model of the filling bed in a specific embodiment of the present invention.

[0163] Figure 11 This is a front view of the geometry and computational domain of the entire packed bed in a specific embodiment of the present invention.

[0164] Figure 12 This is a top view of the geometry and computational domain of the entire packed bed in a specific embodiment of the present invention.

[0165] Figure 13 This is a diagram showing the result of grid division of the entire filling bed computational domain in a specific embodiment of the present invention.

[0166] Figure 14 This is a diagram showing the pressure drop of the packed bed in a specific embodiment of the present invention.

[0167] Figure 15 This is a cross-sectional liquid content diagram of the packed bed in a specific embodiment of the present invention. Detailed Implementation

[0168] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0169] This invention provides an industrial design and optimization method for a gas-liquid distributor applied to a packed bed, the process flow diagram of which is shown below. Figure 1 As shown, the industrial design and optimization method includes the following steps:

[0170] (1) Assuming the minimum diameter and number of the gas-liquid distributor's central cylinder, the opening ratio of the distribution plate, gas-liquid velocity, gas-liquid Re number and pressure drop are obtained through engineering design calculations based on the industrial packed bed diameter and gas-liquid flow rate.

[0171] Determine whether the assumed minimum diameter and number of the gas-liquid distributor's central cylinders meet the range of distribution plate opening ratio, gas-liquid velocity, gas-liquid Reynolds number, and pressure drop in industrial design; if not, repeat this step; if yes, proceed to the next step.

[0172] (2) Based on the minimum diameter of the gas-liquid distributor center cylinder and the geometric dimensions of a single gas-liquid distributor described in step (1), the gas-liquid distribution of a single gas-liquid distributor is simulated and calculated using computational fluid dynamics. The spray area of ​​a single gas-liquid distributor and the number of gas-liquid distributors described in step (1) are used to verify whether the spray area of ​​the gas-liquid distributor covers the entire cross-section of the packed bed.

[0173] Determine whether the spray area of ​​the gas-liquid distributor can cover the entire cross-section of the packed bed. If not, repeat this step; if yes, proceed to the next step.

[0174] (3) Simplify a single gas-liquid distributor into a circular hole, use computational fluid dynamics to simulate and calculate the gas-liquid distribution of the packed bed, and determine whether the pressure drop of the packed bed and the uniformity of the gas-liquid distribution meet the industrial design requirements; if not, repeat steps (1) to (3); if yes, the industrial design optimization ends, and the diameter and number of gas-liquid distributor center cylinders are obtained.

[0175] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0176] As a specific embodiment of the present invention, an industrial design and optimization method for a gas-liquid distributor applied to a packed bed is provided, the industrial design and optimization method comprising the following steps:

[0177] (1) Assuming the minimum diameter of the gas-liquid distributor's central cylinder is d0 = 36 mm, the number of distributors is n = 270, and they are arranged in an equilateral triangle, the schematic diagram of the position of the packed bed and the gas-liquid distributor is as follows: Figure 2 As shown;

[0178] Based on an industrial packed bed diameter D = 1.6m and a gas flow rate q gas =961.1(m) 3 / h) and liquid flow rate q oil =15.03(m) 3 / h), through engineering design calculations, the distribution plate opening ratio, gas-liquid velocity, gas-liquid Re number and pressure drop are obtained;

[0179] The formula for calculating the opening ratio of the central cylinder distribution plate is:

[0180]

[0181] Where: n - the number of gas-liquid distributors;

[0182] d0 - Minimum diameter of the central cylinder of the gas-liquid distributor, in mm;

[0183] D - Diameter of the packed bed, in meters;

[0184] The gas-liquid velocity includes both gas velocity and liquid velocity;

[0185] The formula for calculating the gas velocity is:

[0186]

[0187] Where: q gas -Gas flow rate, m 3 / h;

[0188] The formula for calculating the liquid velocity is:

[0189]

[0190] Where: q oil - Liquid flow rate, m 3 / h;

[0191] The gas-liquid Re number includes the gas Re number and the liquid Re number;

[0192] The formula for calculating the Reynolds number of the gas is:

[0193]

[0194] Where: ρ gas - is the density of the gas, kg / m³ 3 ;

[0195] ν gas - is the gas viscosity, mPa·s;

[0196] The formula for calculating the Re number of the liquid is:

[0197]

[0198] Where: ρ oil - is the density of the liquid, kg / m³ 3 ;

[0199] ν oil - is the viscosity of the liquid, in mPa·s.

[0200] The gas-liquid distributor is a bubble-type gas-liquid distributor with a liquid-breaking plate.

[0201] Distributor voltage drop: Δp dist =2050.6 Pa;

[0202] The pressure drop calculation formula for the bubble-type gas-liquid distributor is as follows:

[0203] lg(Δp')=1.509q oil -0.088 +0.035U gas ;

[0204] Δp dist =9.807×10 3 Δp';

[0205] Where: Δp dist - Pressure drop of the gas-liquid distributor;

[0206] It was determined that the minimum diameter and number of central cylinders of the hypothetical gas-liquid distributor meet the requirement of a distribution plate opening ratio of 5% < ε in industrial design. plat < e 20%, gas velocity 0.1 < U gas <3. Liquid velocity 0.1 < U oil <1, 1 < Re gas <10000, 1<Re oil <10000, and pressure drop 200 < Δp dist If the value is less than 4000, proceed to the next step.

[0207] (2) Based on the minimum diameter of the gas-liquid distributor center cylinder and the geometric dimensions of a single gas-liquid distributor described in step (1), the gas-liquid distribution of a single gas-liquid distributor is simulated and calculated using computational fluid dynamics. The spray area of ​​a single gas-liquid distributor and the number of gas-liquid distributors described in step (1) are used to verify whether the spray area of ​​the gas-liquid distributor covers the entire cross-section of the packed bed.

[0208] A schematic diagram of the composition of the single gas-liquid distributor is shown below. Figure 3 As shown;

[0209] The steps for simulating the gas-liquid distribution of a single gas-liquid distributor using computational fluid dynamics methods include:

[0210] (A) Based on the geometric dimensions of the individual gas-liquid distributor, a three-dimensional geometric model of the individual gas-liquid distributor is created using Solidworks, as shown in the schematic diagram below. Figure 4 As shown; the geometric dimensions of the single gas-liquid distributor include the central cylinder diameter d0, the first central cylinder height h1, the second central cylinder height h3, the bubble cap diameter d1, the bubble cap height h4, the distance between the top of the bubble cap and the top of the central cylinder h2, the number of bubble cap slots, the height h5, and the static liquid level height h6; the geometric dimensional relationships of the single gas-liquid distributor include: d1 = (1.1~5)d0 = 50mm, h1 = (2~20)d0 = 67mm, h2 = (0.1~5)d0 = 11mm, h3 = (0.1~5)d0 = 20mm, h4 = (2~20)d0 = 63mm, h5 = (0.1~5)d0 = 16mm, h6 = (0.1~10)d0 = 10mm;

[0211] The geometric dimensions and computational domain diagram of the single gas-liquid distributor are shown below. Figure 5 As shown;

[0212] (B) Perform topological analysis on the three-dimensional geometric model of the single gas-liquid distributor, and use a hybrid meshing scheme that combines structured and unstructured meshes to mesh the computational domain of the single gas-liquid distributor.

[0213] A high-quality hexahedral structured mesh was used for the entire outer area of ​​the downcomer, while a hybrid mesh scheme combining hexahedral structured mesh and pentahedral prism unstructured mesh was used for the downcomer area. In the end, a high-quality mesh that meets the actual needs of the project was established.

[0214] During the mesh generation process, mesh densification and irrelevance verification are performed on the wall surface, openings, and other locations of a single gas-liquid distributor.

[0215] (C) Define the computational domain boundary for a single gas-liquid distributor, select a 3D implicit solver and an Euler-Euler multiphase model, and couple a population equilibrium model; the inlet of the computational domain boundary for the single gas-liquid distributor is a given gas-liquid flow rate: q gas,1 =q gas / n=2.75(m 3 / h), q oil,1 =q oil / n=0.04(m 3 / h); the circumferential direction is the wall, and the outlet is the outflow boundary with zero static pressure;

[0216] (D) Initialize the computational domain of a single gas-liquid distributor, perform iterative calculations, and stop the loop when the residuals meet the calculation requirements;

[0217] (E) Export the numerical simulation results of the flow of a single gas-liquid distributor, obtain the coefficient of variation of the liquid velocity at the outlet of the computational domain of a single gas-liquid distributor, and calculate the equivalent spray radius;

[0218] The formula for calculating the coefficient of variation (CV) of the outlet liquid velocity in the computational domain of a single gas-liquid distributor is as follows:

[0219]

[0220] Where: N - number of grid cells at the exit section;

[0221] U oil - Local liquid velocity at grid points, m / s;

[0222] - Average liquid velocity at the outlet section, m / s.

[0223] The equivalent spray radius R in step (E) c The calculation formula is:

[0224]

[0225] Wherein: S c -Spray area (m) 2 A single-variable operating condition simulation was performed with parameters d1 = 50 mm, h1 = 67 mm, h2 = 11 mm, h3 = 20 mm, h4 = 63 mm, h5 = 16 mm, and h6 = 10 mm. Other variables remained constant, with bubble cap diameters d1 = 50, 53, and 56 mm. The resulting graph of the coefficient of variation of the outlet liquid velocity in the calculation domain of a single gas-liquid distributor is shown below. Figure 6 As shown; the result diagram of the equivalent spray radius is as follows. Figure 7 As shown; the pressure drop result of a single gas-liquid distributor is shown in the figure. Figure 8As shown; a smaller bubble diameter results in a larger coefficient of variation for liquid velocity, a smaller spray radius, and a larger pressure drop; through single-factor analysis and orthogonal experiments, the optimal structural dimensions of a single gas-liquid distributor were obtained: d1 = 56 mm, h1 = 57 mm, h2 = 10 mm, h3 = 19 mm, h4 = 65 mm, h5 = 17 mm.

[0226] If the spray area of ​​the gas-liquid distributor covers less than 99% of the cross-sectional area of ​​the entire packed bed, or the coefficient of variation of the liquid velocity CV is less than 1, then proceed to the next step.

[0227] (3) Simplify a single gas-liquid distributor into a circular hole, and use computational fluid dynamics to simulate and calculate the gas-liquid distribution of the packed bed, and determine whether the pressure drop and gas-liquid distribution uniformity of the packed bed meet the industrial design requirements, including energy consumption requirements, power system requirements and temperature distribution requirements;

[0228] If not, repeat steps (1) to (3); if yes, the industrial design optimization ends, and the diameter and number of the gas-liquid distributor center cylinder are obtained.

[0229] In this specific embodiment, the packed bed is a trickle bed, and its structural schematic diagram is shown below. Figure 9 As shown, its three-dimensional geometric model is as follows: Figure 10 As shown;

[0230] The steps of simulating the gas-liquid distribution of the entire packed bed using computational fluid dynamics include:

[0231] (A') Based on the minimum diameter and number of the central cylinder of a single gas-liquid distributor and the diameter of the packed bed, a three-dimensional geometric model of the entire packed bed and its gas-liquid distributor is established using Solidworks, wherein the particle gradation in the packed bed is divided into m regions.

[0232] (B') An unstructured meshing scheme is adopted to mesh the entire computational domain of the filled bed;

[0233] The main view of the geometry and computational domain of the entire packed bed is as follows: Figure 11 As shown, the top view is as follows Figure 12 As shown; the result of the mesh generation of the entire packed bed computational domain is as follows. Figure 13 As shown;

[0234] (C') Define the computational domain boundary for the entire packed bed, and select the Euler-Euler multiphase model within the porous medium; the n inlet holes in the computational domain boundary of the entire packed bed represent a given gas-liquid flow rate: q gas,1 =q gas / n=2.75(m 3 / h), q oil,1 =q oil / n=0.04(m3 / h); the circumferential direction is the wall, and the outlet is the outflow boundary with zero static pressure;

[0235] (D') Initialize the computational domain of the entire packed bed, perform iterative calculations, and stop the loop when the residuals meet the calculation requirements;

[0236] (E') Export the numerical simulation results of gas-liquid flow throughout the packed bed, showing that the pressure drop of the packed bed is reasonable and the liquid distribution is uniform across the cross-section; the pressure drop results of the packed bed are as follows: Figure 14 As shown; the liquid content in the cross-section of the packed bed is as follows: Figure 15 As shown.

[0237] In this specific embodiment, the final geometric dimensions of the gas-liquid distributor are d0 = 30mm, d1 = 50mm, h1 = 67mm, h2 = 11mm, h3 = 20mm, h4 = 63mm, h5 = 16mm, h6 = 10mm, arranged in an equilateral triangle, with a central cylinder diameter of 75mm and a number of 270.

[0238] In summary, the industrial design and optimization method for gas-liquid distributors applied to packed beds provided by this invention achieves multi-scale and multi-angle optimization design of the gas-liquid distributor, with a short optimization and adjustment cycle and low design cost. The resulting gas-liquid distributor has a central cylinder diameter and number that better meet the needs of practical engineering applications.

[0239] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An industrial design and optimization method for a gas-liquid distributor applied to a packed bed, characterized in that, The industrial design and optimization method includes the following steps: (1) Assuming the minimum diameter and number of the gas-liquid distributor's central cylinder, the opening ratio of the distribution plate, gas-liquid velocity, gas-liquid Re number and pressure drop are obtained through engineering design calculations based on the industrial packed bed diameter and gas-liquid flow rate; Determine whether the minimum diameter and number of the central cylinder of the hypothesized gas-liquid distributor meet the range of distribution plate opening ratio, gas-liquid velocity, gas-liquid Re number and pressure drop in industrial design; if not, repeat this step. Yes, then proceed to the next step; (2) Based on the minimum diameter of the central cylinder of the gas-liquid distributor described in step (1) and the geometric dimensions of a single gas-liquid distributor, the gas-liquid distribution of a single gas-liquid distributor is simulated and calculated using computational fluid dynamics. The spray area of ​​a single gas-liquid distributor and the number of gas-liquid distributors described in step (1) are used to verify whether the spray area of ​​the gas-liquid distributor covers the entire cross-section of the packed bed. The steps for simulating the gas-liquid distribution of a single gas-liquid distributor using computational fluid dynamics methods include: (A) Based on the geometric dimensions of the individual gas-liquid distributor, a three-dimensional geometric model of the individual gas-liquid distributor is established using Solidworks; (B) Perform topological analysis on the three-dimensional geometric model of the single gas-liquid distributor, and use a hybrid meshing scheme that combines structured and unstructured meshes to mesh the computational domain of the single gas-liquid distributor; (C) Define the computational domain boundary for a single gas-liquid distributor, select a 3D implicit solver and an Euler-Euler multiphase model, and couple the population equilibrium model; (D) Initialize the computational domain of a single gas-liquid distributor, perform iterative calculations, and stop the loop when the residuals meet the calculation requirements; (E) Export the numerical simulation results of the flow of a single gas-liquid distributor, obtain the coefficient of variation of the liquid velocity at the outlet of the computational domain of a single gas-liquid distributor, and calculate the equivalent spray radius; Determine whether the spray area of ​​the gas-liquid distributor can cover the entire cross-section of the packed bed. If not, repeat this step; if yes, proceed to the next step. (3) Simplify a single gas-liquid distributor into a circular hole, use computational fluid dynamics to simulate and calculate the gas-liquid distribution of the packed bed, and determine whether the pressure drop of the packed bed and the uniformity of the gas-liquid distribution meet the industrial design requirements; if not, repeat steps (1) to (3); if yes, the industrial design optimization ends, and the diameter and number of the gas-liquid distributor center cylinder are obtained. The steps of simulating the gas-liquid distribution of the entire packed bed using computational fluid dynamics include: (A') Based on the minimum diameter and number of central cylinders of a single gas-liquid distributor and the diameter of the packed bed, a three-dimensional geometric model of the entire packed bed and its gas-liquid distributor is established using Solidworks, wherein the particle size distribution within the packed bed is divided into... m One region; (B') An unstructured meshing scheme is adopted to mesh the entire computational domain of the filled bed; (C') Set the computational domain boundary for the entire packed bed and select the Euler-Euler multiphase model within the porous medium; (D') Initialize the computational domain of the entire packed bed, perform iterative calculations, and stop the loop when the residuals meet the calculation requirements; (E') Export the numerical simulation results of gas-liquid flow in the entire packed bed and analyze its radial and axial gas-liquid distribution and its uniformity.

2. The industrial design and optimization method according to claim 1, characterized in that, The formula for calculating the opening ratio of the central cylinder distribution plate in step (1) is as follows: ； in: - The number of gas-liquid distributors; -Minimum diameter of the central cylinder of the gas-liquid distributor, mm; - The diameter of the packed bed, in meters; The gas-liquid velocity includes both gas velocity and liquid velocity; The formula for calculating the gas velocity is: ； in: -Gas flow rate, m 3 / h; The formula for calculating the liquid velocity is: in: - Liquid flow rate, m 3 / h; The gas-liquid Re number includes the gas Re number and the liquid Re number; The formula for calculating the Reynolds number of the gas is: ； in: - Density of the gas, kg / m³ 3 ; -Gas viscosity, mPa·s; The formula for calculating the Re number of the liquid is: ； in: - The density of the liquid, kg / m³ 3 ; - Liquid viscosity, mPa·s.

3. The industrial design and optimization method according to claim 2, characterized in that, The gas-liquid distributor includes a bubble-type gas-liquid distributor, an overflow-type gas-liquid distributor, a jet-type distributor, a venturi-type gas-liquid distributor, and a gas-liquid distributor with a liquid-breaking plate. The pressure drop calculation formula for the bubble-type gas-liquid distributor is as follows: ； ； in: - Pressure drop of the gas-liquid distributor; The pressure drop calculation formula for the overflow-type gas-liquid distributor is as follows: ； ； in: -Pressure drop resistance coefficient; The pressure drop calculation formula for the jet-type distributor is as follows: ； ； The pressure drop calculation formula for the Venturi-type gas-liquid distributor is as follows: ； The pressure drop calculation formula for the gas-liquid distributor with liquid breaking plate is as follows: 。 4. The industrial design and optimization method according to claim 1, characterized in that, The geometry of the single gas-liquid distributor in step (2) includes the diameter of the central cylinder. First height of the central tube Second height of the central tube , blister diameter , blister height Distance between the top of the blister pack and the top of the center tube The number of blister pack seams and the height of the circumferential seams around the blister pack. And the static liquid level height h6.

5. The industrial design and optimization method according to claim 4, characterized in that, The geometric dimensions of the single gas-liquid distributor in step (A) include: ， ， ， ， ， ， ； In step (B), during the mesh generation process, mesh refinement and irrelevance verification are performed on the wall surface and openings of a single gas-liquid distributor. In step (C), the inlet of the computational domain in the computational domain boundary of the single gas-liquid distributor is a given gas-liquid flow rate: , The circumferential direction is the wall surface, and the outlet is the outflow boundary with zero static pressure.

6. The industrial design and optimization method according to claim 1, characterized in that, Step (E) The coefficient of variation of the outlet liquid velocity in the computational domain of the single gas-liquid distributor The calculation formula is: ； Where: N - number of grid cells at the exit section; - Local liquid velocity at grid points, m / s; - Average liquid velocity at the outlet section, m / s; The equivalent spray radius in step (E) The calculation formula is: ； in: -Spraying area, m 2 .

7. The industrial design and optimization method according to claim 1, characterized in that, The geometry of a single gas-liquid distributor is evaluated and optimized based on the liquid velocity variation coefficient and the static liquid level height.

8. The industrial design and optimization method according to claim 2, characterized in that, In step (C'), the computational domain boundary of the entire packed bed n Each small inlet is for a given gas-liquid flow rate: , The circumferential direction is the wall surface, and the outlet is the outflow boundary with zero static pressure.

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