Double-throat gas-assisted superfine atomizing nozzle

Abstract

A double-throat gas-assisted superfine atomizing nozzle comprises a central gas channel, an annular liquid channel, a first throat, a turbulence mixing chamber and a second throat which are coaxially arranged. The first throat and the second throat are designed to be Laval nozzles; an outlet of the central gas channel is hermetically communicated with a contraction pipe of a first throat, an expansion pipe of the first throat is hermetically communicated with an inlet of the turbulence mixing chamber, and at least one fluid mixing inlet is formed in the pipe wall of the expansion pipe of the first throat; the central airflow primarily crushes the fluid in the first throat to obtain an unstable thin liquid film, and enters the turbulent flow mixing chamber at the same time; the unstable thin liquid film is further crushed into small-particle-size liquid drops with SMD smaller than or equal to 60 micrometers through the second throat and then discharged. According to the utility model, the structure is innovative, and a double crushing mechanism is realized through the high-speed-difference shearing action of central gas and liquid and the'gas-in-liquid 'structural design of annular input of a peripheral liquid film in combination with the two-stage Laval nozzle.

Description

Technical Field

[0001] This utility model belongs to the field of fluid atomization technology, and in particular relates to a dual-throat gas-assisted ultrafine atomizing nozzle. Background Technology

[0002] With the continuous advancement of technology, in heavy industrial fields, such as petrochemical catalytic cracking feedstock oil atomization and high-temperature flue gas rapid cooling, traditional atomizing nozzles generally face the following technical bottlenecks:

[0003] Single atomization limit: Conventional gas-liquid mixing nozzles achieve atomization only through a single pneumatic shear (such as traditional air atomizing nozzles) or mechanical centrifugation (such as centrifugal nozzles), and the droplet size is generally greater than 150μm, resulting in insufficient contact area between feedstock and catalyst in catalytic cracking reactions.

[0004] Low energy utilization efficiency: the kinetic energy of the gas cannot be released in layers. For example, an air atomizing nozzle needs to consume 2 to 3 times the high-pressure gas flow rate of the liquid.

[0005] Poor structural adaptability: Existing "gas-liquid" type nozzles (such as the design of annular gas channels wrapping the central liquid flow) only form a single shear surface and cannot achieve multi-stage crushing. Utility Model Content

[0006] The purpose of this invention is to provide an ultrafine atomizing nozzle that can achieve multiple shearing and crushing effects and produce small particle sizes.

[0007] To achieve the above objectives, a specific method is provided: a dual-throat gas-assisted ultrafine atomizing nozzle, comprising a central gas channel, an annular liquid channel, a first throat, a turbulent mixing chamber, and a second throat arranged coaxially; the first and second throats are designed as Laval nozzles, each comprising a converging tube, a throat, and an expanding tube arranged sequentially; the outlet of the central gas channel is sealed and connected to the converging tube of the first throat, and the expanding tube of the first throat is sealed and connected to the inlet of the turbulent mixing chamber; the wall of the expanding tube of the first throat is provided with at least one fluid mixing inlet; the annular liquid channel has at both ends... A sealing ring is disposed on the outer ring including the first throat and at least part of the central gas channel, and one end of the annular liquid channel is sealed at the outer end of the expansion tube of the first throat. The annular liquid channel has at least one fluid inlet on its outer wall. The fluid entering the fluid inlet enters the expansion tube of the first throat due to the pressure difference along at least one fluid mixing inlet, so that the central airflow entering the central gas channel can accelerate the fluid to subsonic or supersonic speed in the first throat, achieving primary crushing. The outlet of the turbulent mixing chamber is sealed and connected to the contraction tube of the second throat, and the intensity of turbulent pulsation is increased through the second throat, further crushing the fluid.

[0008] Furthermore, at least one fluid inlet of the annular liquid channel is designed to be angled toward the expansion tube of the first throat, with an angle of 30° to 45° between it and the outer wall of the annular liquid channel, which facilitates the fluid to enter the fluid mixing inlet smoothly.

[0009] Furthermore, the conical angle of the expansion tube of the second throat is 10° to 60°.

[0010] Furthermore, the expansion tube wall of the first throat is provided with multiple fluid mixing inlets evenly distributed.

[0011] Furthermore, the turbulent mixing chamber is further provided with swirl blades, the number of which is 6 to 8.

[0012] A further intelligent control module is provided, specifically an integrated PID adjustment module. The intelligent control module dynamically adjusts the flow ratio of the central airflow to the incoming fluid to 0.7 to 1.5 based on the infrared temperature measurement signal of the flue.

[0013] Furthermore, the ratio of the larynx diameter of the first larynx to that of the second larynx is 0.7 to 1.5.

[0014] This utility model has the following beneficial effects:

[0015] This utility model features an innovative structure that utilizes a "liquid-encased gas" design—a combination of a central gas-liquid high-velocity differential shearing action and an outer liquid film annular input—to achieve a dual fragmentation mechanism through a two-stage Laval nozzle.

[0016] Thermal shock resistant design: The nozzle head is coated with CoCrAlY (0.8mm thick, coefficient of thermal expansion 9.6×10⁻). 6 ( / ℃), withstands thermal shock at 1000℃;

[0017] Three-dimensional atomization optimization: The second throat outlet is set with a diffusion cone angle of up to 60°, and the atomization coverage angle reaches 120°, forming a three-dimensional cooling barrier;

[0018] Intelligent control: The integrated PID control module dynamically adjusts the gas-liquid ratio based on the infrared temperature measurement signal from the flue, achieving a better degree of gas-liquid mixing and further ensuring the effect of dual crushing.

[0019] Engineering data: Actual cooling rate ≥200℃ / s, droplet evaporation rate ≥99%, water saving ≥40% compared to traditional fan-shaped spray nozzles, gas energy consumption reduced by more than 50%, achieving excellent high efficiency and energy saving technical effects.

[0020] This patent reduces the atomization particle size to below 60μm, making it particularly suitable for applications such as efficient atomization of feedstock oil in catalytic cracking units or rapid cooling of high-temperature flues. Attached Figure Description

[0021] Figure 1 This is an exploded view of Embodiment 1 of the present invention;

[0022] Figure 2 , 3 This is an assembly diagram of Embodiment 1 of the present utility model;

[0023] Figure 4 This is a cross-sectional schematic diagram of Embodiment 1 of the present utility model. Detailed Implementation Example 1

[0024] like Figures 1-4 As shown, a dual-throat gas-assisted ultrafine atomizing nozzle 10 includes a central gas channel 1, an annular liquid channel 2, a first throat, a turbulent mixing chamber 4, and a second throat arranged coaxially. Both the first and second throats are designed as Laval nozzles, each comprising a converging tube, a throat, and an expanding tube arranged sequentially, referred to herein as the first Laval nozzle 3 and the second Laval nozzle 5. The outlet of the central gas channel 1 is sealed and connected to the converging tube 31 of the first Laval nozzle (first throat), and the expanding tube 32 (first expanding tube) of the first Laval nozzle is sealed and connected to the inlet of the turbulent mixing chamber 4. In this embodiment, four fluid mixing inlets 321 are evenly distributed on the wall of the expanding tube 32 of the first Laval nozzle.

[0025] The annular liquid channel 2 is sealed at both ends with sealing rings on the outer ring of the first Laval nozzle and at least part of the central gas channel 1, and one end of the annular liquid channel 2 is sealed at the outer end of the expansion tube 32 of the first Laval nozzle, such as... Figure 4 As shown, the central gas channel 1 extends from the outside into the annular liquid channel 2 and further extends to the constriction tube 31 of the first Laval nozzle for sealing and conduction;

[0026] The annular liquid channel 2 has a fluid inlet 21 on its outer wall. In this embodiment, the fluid inlet 21 is designed to be angled towards the expansion tube 32 of the first Laval nozzle 3, with an angle α between it and the outer wall of the annular liquid channel 2 being 45°. Figure 4 As shown, the fluid enters the expansion tube 32 of the first Laval nozzle 3 from the fluid mixing inlet 321 by means of pressure difference and siphon principle.

[0027] The fluid entering the fluid inlet 21 enters the expansion tube 32 of the first Laval nozzle 3 through at least one fluid mixing inlet 321 due to the pressure difference, so that the central airflow of the central gas passage 1 can accelerate the fluid to subsonic or supersonic speeds, approximately 200 m / s to 800 m / s, in the first Laval nozzle 3, thereby achieving primary fragmentation to obtain an unstable thin liquid film, and simultaneously entering the turbulent mixing chamber 4;

[0028] The turbulent mixing chamber 4 is designed as a tube, and its outlet is sealed and connected to the contraction tube 51 of the second Laval nozzle (second throat). The second Laval nozzle 5 increases the intensity of turbulent pulsation, further breaking the unstable thin liquid film into small droplets with a diameter (SMD) ≤ 60 μm, which are then discharged. In this embodiment, the conical angle of the expansion tube 53 (second expansion tube) of the second Laval nozzle is 10° to 60°. In this embodiment, the outlet of the second throat forms a "gas-liquid-gas" dual shear interface with an external shear Reynolds number Re ≥ 5000.

[0029] As shown in the figure, a ring-shaped protective sleeve 6 is fixed to the outside of the second Laval nozzle 5.

[0030] In some embodiments, the turbulent mixing chamber 4 may be further provided with swirl blades, the number of which is 6 to 8 and the number of swirl blades Sn = 0.6 to 0.8, thereby increasing the intensity of turbulent pulsation and achieving a better droplet breaking effect.

[0031] An intelligent control module can be further configured, specifically an integrated PID adjustment module. The intelligent control module dynamically adjusts the flow ratio of the central airflow to the incoming fluid to 0.7 to 1.5 based on the infrared temperature measurement signal of the flue.

[0032] In application, the throat diameter ratio D1:D2 of the first throat and the second throat is 0.7 to 1.5. This ratio increases with the increase of the mass ratio of the auxiliary atomizing gas and decreases with the increase of the atomizing liquid working fluid.

[0033] The central airflow inlet directs the flow, and the fluid enters the Laval nozzle through the circumferential fluid mixing inlet 321. This design mechanism naturally forces the fluid (liquid) against the wall of the expansion tube 32 to form an annular structure. During the mixing process, the structure gradually transitions from a "liquid-encased gas" state to full mixing.

[0034] Further, using standard testing techniques, the technical parameters of this patented product are compared with those of traditional air atomizing nozzles, as shown in Table 1 below:

[0035] index Traditional air atomizing nozzles This utility model features a double-throat double-shear nozzle. Average droplet size (SMD) ≥150μm ≤50μm Assist gas mass flow rate ≥10% ≤5% Atomization energy conversion efficiency Low high Anti-clogging performance Easy to clog Circular channel, less prone to blockage

[0036] The conventional air atomizing nozzle is a CS nozzle.

[0037] Detection equipment: Phase Doppler interferometer (PDA), which measures droplet velocity and particle size through the Doppler effect and calculates particle size by combining the phase difference. Example 2

[0038] The dual-throat gas-assisted ultrafine atomizing nozzle described in Example 1 was applied to the efficient atomization of feedstock oil in a catalytic cracking unit, specifically under the following implementation environment:

[0039] Application operating parameters:

[0040] Feed rate of crude oil: 146 t / h;

[0041] Auxiliary atomizing steam mass flow rate: 5%

[0042] Number of nozzles: 6

[0043] Crude oil specific gravity (d420): 0.9400

[0044] Crude oil viscosity (mm² / s): 4.11 @ 100℃

[0045] Nozzle structural parameters:

[0046] First throat design: throat diameter D1=26mm, expansion tube cone angle 15.3°;

[0047] Turbulent mixing chamber: length L=650mm, equipped with turbulence enhancers (swirl blades), number of 6 swirl blades, tilt angle 45°), to achieve gas-liquid mixing uniformity ≥95%;

[0048] Second throat design: throat diameter D2 = 28.9 mm, expansion tube cone angle 19.8°.

[0049] Effect verification:

[0050] The feedstock oil enters the central gas channel 1 of each nozzle during feeding, and simultaneously, auxiliary atomizing steam is introduced through the fluid inlet 21 on the side wall of the annular liquid channel 2. After a certain period of atomization, the atomization effect is detected; the SMD is 58μm as measured by a Doppler laser particle size analyzer. This reduces the catalyst coking rate by 37% compared to traditional nozzles. Example 3

[0051] The aforementioned dual-throat gas-assisted ultrafine atomizing nozzle is used for rapid cooling of high-temperature flues, as described in the following implementation environment:

[0052] Application operating parameters:

[0053] Flue gas inlet temperature: 670℃

[0054] Flue gas outlet temperature: 300℃

[0055] Flue gas inlet pressure: 0.01 MPa

[0056] Flue gas outlet pressure: 0.008 MPa

[0057] Flue gas flow rate: 200,000 Nm 3 / h

[0058] Desuperheating water temperature: room temperature

[0059] Desuperheating water pressure: 0.4 MPa

[0060] Desuperheating water flow rate: approximately 50 t / h

[0061] Auxiliary atomizing non-purified air pressure: 0.6~0.8 MPa

[0062] Auxiliary atomizing non-purified air temperature: 40℃

[0063] Assisted atomization non-purification airflow: 1,345 Nm 3 / h

[0064] Number of nozzles: 8

[0065] Nozzle structural parameters:

[0066] First throat design: throat diameter D1=26mm, expansion tube cone angle 15.3°;

[0067] Turbulent mixing chamber: length L=650mm, equipped with turbulence enhancers (swirl blades), number of 6 swirl blades, tilt angle 45°), to achieve gas-liquid mixing uniformity ≥95%;

[0068] Second throat design: throat diameter D2 = 28.9 mm, extension tube cone angle 19.8°. Nozzle head uses CoCrAlY coating (thickness 0.8 mm, coefficient of thermal expansion 9.6 × 10⁻⁻). 6 ( / ℃), withstands thermal shock at 1000℃;

[0069] Intelligent control module: integrates a PID adjustment module, which dynamically adjusts the ratio of central airflow to incoming fluid (0.7~1.5) based on the infrared temperature measurement signal of the flue.

[0070] Engineering data:

[0071] The flue gas outlet is sealed and connected to the central gas channel 1 of each nozzle. The flue gas to be cooled enters the central gas channel 1 of each nozzle. At the same time, auxiliary atomizing non-purified air and cooling water are introduced through the fluid inlet 21 on the side wall of the annular liquid channel 2. After a certain period of atomization and cooling, the atomization and cooling effect is tested. The actual measured cooling rate is ≥200℃ / s, the droplet evaporation rate is ≥99%, and the water saving is ≥40% compared with the traditional fan-shaped spray nozzle.

[0072] Three-dimensional atomization optimization: The application presents a cone angle of about 60° at the outlet diffusion of the second throat, and the atomization coverage angle reaches 120°, forming a three-dimensional cooling barrier, which further improves the cooling effect.

[0073] This patent employs a dual-shear surface synergistic atomization structure:

[0074] Liquid-gas fluid topology: It adopts a central gas channel + peripheral annular liquid channel design (opposite to the traditional "gas-liquid" structure), forming a "gas-liquid-gas" sandwich flow interface at the nozzle outlet;

[0075] Double shearing from both inside and outside:

[0076] Internal shear: The high-speed gas at the center and the surrounding liquid film generate the first shear layer;

[0077] External shear: The liquid film forms a second shear layer with the ambient gas (Reynolds number Re≥5000), achieving a dual fragmentation effect.

[0078] The above embodiments are for illustrative purposes only and are not intended to limit the present invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention and should be defined by the claims.

Claims

1. A dual-throat gas-assisted ultrafine atomizing nozzle, characterized in that: The system comprises a central gas channel, an annular liquid channel, a first throat, a turbulent mixing chamber, and a second throat, all coaxially arranged. The first and second throats are designed as Laval nozzles, each comprising a converging tube, a throat, and an expanding tube arranged sequentially. The outlet of the central gas channel is sealed and connected to the converging tube of the first throat, and the expanding tube of the first throat is sealed and connected to the inlet of the turbulent mixing chamber. The expanding tube of the first throat has at least one fluid mixing inlet on its wall. The annular liquid channel has sealing rings at both ends on the outer ring of the system, including the first throat and at least a portion of the central gas channel. One end of the annular liquid channel is sealed at the outer end of the expanding tube of the first throat. The annular liquid channel has at least one fluid inlet on its outer wall. Fluid entering the fluid inlet, due to pressure difference, flows through at least one fluid mixing inlet into the expanding tube of the first throat, allowing the central airflow entering the central gas channel to accelerate the fluid to subsonic or supersonic speeds in the first throat, achieving primary breakup. The outlet of the turbulent mixing chamber is sealed and connected to the converging tube of the second throat, further enhancing the turbulent pulsation intensity through the second throat, thus further breaking up the system.

2. The dual-throat gas-assisted ultrafine atomizing nozzle as described in claim 1, characterized in that: At least one fluid inlet of the annular liquid channel is designed to be angled toward the expansion tube of the first throat, with an angle of 30° to 45° between it and the outer wall of the annular liquid channel, which facilitates the fluid to enter the fluid mixing inlet smoothly.

3. The dual-throat gas-assisted ultrafine atomizing nozzle as described in claim 1, characterized in that: The conical angle of the expansion tube of the second throat is 10° to 60°.

4. The dual-throat gas-assisted ultrafine atomizing nozzle as described in claim 1, characterized in that: Multiple fluid mixing inlets are evenly distributed on the wall of the expansion tube of the first throat.

5. The dual-throat gas-assisted ultrafine atomizing nozzle as described in claim 1, characterized in that: The turbulent mixing chamber is further provided with swirl blades, the number of which is 6 to 8.

6. The dual-throat gas-assisted ultrafine atomizing nozzle as described in claim 1, characterized in that: A further intelligent control module is provided, specifically an integrated PID adjustment module. The intelligent control module dynamically adjusts the flow ratio of the central airflow to the incoming fluid to 0.7 to 1.5 based on the infrared temperature measurement signal of the flue.

7. The dual-throat gas-assisted ultrafine atomizing nozzle as described in claim 1, characterized in that: The ratio of the diameter of the first larynx to that of the second larynx is 0.7 to 1.5.

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