Noise reduction device for carbon dioxide fracturing operations

Abstract

The application provides a noise reduction device for carbon dioxide fracturing construction, which comprises a cylinder body, the axial two ends of the cylinder body are an inlet end and an outlet end respectively, and a pressure reduction nozzle and a sound attenuation array are arranged in the cylinder body along the axial direction; wherein the pressure reduction nozzle is located at the inlet end, the pressure reduction nozzle is used for being connected with a carbon dioxide discharge pipeline, and a pressure reduction cavity is formed between the pressure reduction nozzle and the inner wall of the cylinder body; the sound attenuation array is located at the middle section of the cylinder body, and a sound attenuation cavity is formed between the sound attenuation array and the inner wall of the cylinder body. The beneficial effects of the application include: the pressure of carbon dioxide is reduced through the pressure reduction nozzle, and then the vibration, friction and surge generated in the discharge process are reduced through the sound attenuation array, so as to reduce the noise pollution in the carbon dioxide discharge process.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, and in particular to a noise reduction device for carbon dioxide fracturing operations. Background Technology

[0002] Ensuring energy security and effectively controlling carbon emissions has always been a top priority for the energy industry. Years of research and practice have shown that carbon dioxide fracturing, oil and gas displacement, and geological sequestration can not only effectively improve oil recovery but also achieve in-situ geological sequestration of carbon dioxide in reservoirs.

[0003] In the petroleum industry, hydraulic fracturing refers to a method of creating fractures in oil and gas reservoirs using hydraulic force during oil or gas extraction; it is also known as hydraulic fracturing. For reservoirs with relatively poor physical properties, relatively dense reservoir fluids, relatively viscous underground crude oil, and insufficient reservoir pressure, carbon dioxide fracturing can be used. Carbon dioxide fracturing can capture, utilize, and store greenhouse gases such as carbon dioxide that cannot be reduced. It is a key technology supporting the achievement of zero-carbon or even negative-carbon goals on the path to green and low-carbon development, an important supporting technology for the clean utilization of fossil energy, and a key technology for building energy systems that are both resilient and flexible.

[0004] On the one hand, carbon dioxide fracturing can increase the driving force of fluid flow in the formation, reduce the viscosity of crude oil, increase the fluidity of crude oil in the formation, and improve the production capacity after fracturing. On the other hand, carbon dioxide fracturing uses carbon dioxide to expand the volume, increase the complexity of the fractures to replenish the reservoir energy, increase the driving force of fluid flow in the formation, improve the flowback efficiency, and improve the single-well recovery rate.

[0005] Regarding existing carbon dioxide fracturing technology, the applicant has identified the following drawbacks during the carbon dioxide injection process: During carbon dioxide injection, vibration, internal medium friction, collisions, and disturbances during pipeline flow, especially during the pressure release phase due to heat exchange, cause significant and frequent pressure changes within the pipeline. The high-speed injection generates significant noise pollution from both the jet and valves, posing a hazard to humans and animals. However, no devices or methods have been found in the existing technology to eliminate or reduce noise and its impact during carbon dioxide fracturing operations.

[0006] Therefore, it is necessary to study a noise reduction device for carbon dioxide fracturing operations to solve the above problems or mitigate their impact. Summary of the Invention

[0007] This invention provides a noise reduction device for carbon dioxide fracturing operations. It reduces the pressure of carbon dioxide through a pressure-reducing nozzle and reduces vibration, friction, and surge generated during the release process through a silencing array, thereby reducing noise pollution during the carbon dioxide release process and effectively solving or mitigating the above problems.

[0008] The noise reduction device for carbon dioxide fracturing operations of the present invention may include a cylinder, the two ends of which are an inlet end and an outlet end, and a pressure reducing nozzle and a silencing array are provided in the cylinder along its axial direction.

[0009] The pressure-reducing nozzle is located at the inlet end and is used to connect to the carbon dioxide emission pipeline. A pressure-reducing cavity is formed between the pressure-reducing nozzle and the inner wall of the cylinder. The silencing array is located in the middle section of the cylinder and a silencing cavity is formed between the silencing array and the inner wall of the cylinder.

[0010] In one embodiment, the pressure-reducing nozzle has a plurality of pressure-reducing nozzle holes on its wall, and the diameter of the pressure-reducing nozzle holes increases sequentially from the inlet end to the outlet end.

[0011] In one embodiment, the silencing array includes multiple silencing plates distributed along the axial direction of the cylinder, with the surface of each silencing plate perpendicular to the axial direction of the cylinder, and the multiple silencing plates working together with the inner wall of the cylinder to form the silencing cavity.

[0012] In one embodiment, the silencing plate has a plurality of through-holes evenly distributed, and the plurality of silencing holes are distributed in a mesh pattern on the surface of the silencing plate.

[0013] In one embodiment, the area of ​​the silencing hole gradually increases along the direction of carbon dioxide flow.

[0014] In one embodiment, the silencing plate is fixed to the inner wall of the cylinder, and a notch is left on one side of it. The two notches of adjacent silencing plates are alternately distributed on both sides of the cylinder.

[0015] In one embodiment, the area of ​​the notch is 1 / 4 to 1 / 2 of the area of ​​the sound-absorbing plate.

[0016] In one embodiment, the noise reduction device further includes a fan located at the outlet end of the cylinder, the fan being used to control the outward flow rate of the carbon dioxide.

[0017] In one embodiment, the noise reduction device further includes a dry ice recovery mechanism located outside the cylinder, the dry ice recovery mechanism being connected to the outlet end via a pipe.

[0018] In one embodiment, the dry ice recovery mechanism includes a separation component and an adsorption component, wherein the separation component is used to separate gaseous carbon dioxide from dry ice, and the adsorption component is used to collect the dry ice separated by the separation component.

[0019] The noise reduction device for carbon dioxide fracturing operations provided by this invention has at least the following advantages compared with the prior art:

[0020] The noise reduction device for carbon dioxide fracturing operations of this invention reduces the pressure of carbon dioxide through a pressure-reducing nozzle, and further reduces vibration, friction, and surge generated during the release process through a silencing array, thereby reducing noise pollution during carbon dioxide release. When applied to carbon dioxide fracturing operations, this noise reduction device can significantly reduce the noise emitted during carbon dioxide discharge, greatly minimizing harm to on-site personnel, nearby residents, and animals. It enables 24-hour operation, avoids disturbance to residents, and extends the available operating time. Attached Figure Description

[0021] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the noise reduction device according to an embodiment of the present invention;

[0023] Figure 2 This is a three-dimensional structural schematic diagram of the noise reduction device according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of a pressure-reducing nozzle according to an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the structure of a sound-absorbing plate according to an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the structure of the sidewall of the sound-absorbing hole according to an embodiment of the present invention;

[0027] Figure 6 yes Figure 2 An enlarged structural diagram of part A in the middle.

[0028] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not drawn to scale.

[0029] Figure label:

[0030] 1-Cylinder body, 11-Inlet end, 12-Outlet end, 13-Fixed support leg, 2-Pressure-reducing nozzle, 21-Pressure-reducing cavity, 22-Pressure-reducing nozzle, 3-Silencer array, 31-Silencer cavity, 32-Silencer plate, 33-Silencer hole, 34-Notch

[0031] 4- Fan, 5- Dry ice recovery mechanism, 6- Discharge pipeline, 7- Ladder. Detailed Implementation

[0032] The invention will now be further described with reference to the accompanying drawings.

[0033] Example 1

[0034] like Figure 1 and Figure 2 As shown, the noise reduction device for carbon dioxide fracturing construction of the present invention may include a cylinder 1, with an inlet end 11 and an outlet end 12 at its two axial ends, and a pressure reducing nozzle 2 and a noise reduction array 3 are provided inside the cylinder 1 along its axial direction.

[0035] The pressure-reducing nozzle 2 is located at the inlet end 11 and is used to connect with the carbon dioxide release pipeline 6. A pressure-reducing cavity 21 is formed between the pressure-reducing nozzle 2 and the inner wall of the cylinder 1. The silencer array 3 is located in the middle section of the cylinder 1 and a silencer cavity 31 is formed between the silencer array 3 and the inner wall of the cylinder 1.

[0036] Specifically, the cylinder 1 serves as the overall outer shell of the noise reduction device. Inside, a specially designed pressure-reducing nozzle 2 and a silencer array 3 reduce noise from the carbon dioxide emission. Its axial ends serve as the carbon dioxide inlet 11 and outlet 12, respectively. The pressure-reducing nozzle 2 is located at the inlet 11 of the cylinder 1, connecting to the carbon dioxide emission pipeline 6. High-pressure carbon dioxide from the emission pipeline 6 enters the pressure-reducing nozzle 2 and then flows at a lower pressure into the pressure-reducing cavity 21 between the nozzle 2 and the inner wall of the cylinder 1. Under the influence of the pressure difference, the carbon dioxide flows towards the silencer array 3. The silencer array 3 is located in the middle section of the cylinder 1, forming a silencer cavity 31 with the inner wall of the cylinder 1. The flow of carbon dioxide within the silencer cavity 31 reduces vibration, friction, and surge, thereby reducing noise pollution during the carbon dioxide emission process. The carbon dioxide, after passing through the silencer array 3, is discharged from the outlet 12 of the cylinder 1.

[0037] The noise reduction device can be applied to carbon dioxide fracturing operations to greatly reduce the noise generated when carbon dioxide is discharged, significantly reduce the harm to on-site construction personnel, nearby residents and animals, enable 24-hour construction, avoid disturbing the public, extend the available construction time, and improve the construction progress.

[0038] Furthermore, such as Figure 1 and Figure 2As shown, the cylinder 1 is vertically oriented, with its inlet end at the bottom and its outlet end 12 at the top. This allows carbon dioxide to flow upwards under pressure difference, overcoming its own weight to reduce flow velocity. Multiple evenly distributed fixed supports 13 are provided at the bottom of the cylinder 1, providing stable support for the entire noise reduction device. The bottoms of the multiple fixed supports 13 can also be connected to form a fixed bracket to further improve stability. It should be noted that the following embodiments are all illustrated using the vertical orientation of the cylinder 1 as an example.

[0039] In one example, such as Figures 1 to 3 As shown, the tube wall of the pressure-reducing nozzle 2 is provided with multiple pressure-reducing nozzle holes 22, and the diameter of the pressure-reducing nozzle holes 22 increases sequentially from the inlet end 11 to the outlet end 12.

[0040] Specifically, the pressure-reducing nozzles 22 on the circumferential side of the pressure-reducing nozzle 2 have the same diameter, and the diameters of the pressure-reducing nozzles 22 on the axial side of the pressure-reducing nozzle 2 increase sequentially from bottom to top. The lower end of the pressure-reducing nozzle 2 is connected to the discharge line 6, and a pressure-reducing nozzle 22 with an inner diameter of 5mm can also be provided at the top of the upper end of the pressure-reducing nozzle 2. In this way, after the high-pressure carbon dioxide enters the pressure-reducing nozzle 2 from the discharge line 6, it is discharged into the pressure-reducing cavity 21 through the gradually increasing pressure-reducing nozzles 22 from bottom to top of the pressure-reducing nozzle 2, so as to achieve the effect of progressively distributed pressure reduction.

[0041] It should be noted that the diameter of the pressure-reducing nozzle 2 is larger than that of the discharge line 6, so carbon dioxide undergoes a first pressure reduction when entering the pressure-reducing nozzle 2 from the discharge line 6. The inner diameter of the cylinder 1 is much larger than that of the pressure-reducing nozzle 2, so carbon dioxide undergoes a second pressure reduction when entering the pressure-reducing cavity 21 formed between the pressure-reducing nozzle 2 and the cylinder 1 through the pressure-reducing nozzle orifice 22 of the pressure-reducing nozzle 2. The pressure reduction effect varies depending on the orifice diameter of the pressure-reducing nozzle 22, and gradually increases from bottom to top. After entering the pressure-reducing cavity 21, carbon dioxide flows from bottom to top towards the silencer array 3 under the influence of the pressure difference.

[0042] Furthermore, the cylinder 1 has a cylindrical structure with an axial length of 5m and an inner diameter of 2.5m; the pressure-reducing nozzle 2 has an axial length of 1m, an inner diameter of 36.4mm, and an outer diameter of 50.4mm; the pressure-reducing nozzle 22 has an inner diameter of 5-10mm. The pressure-reducing nozzle 2 should be made of a temperature- and corrosion-resistant material, such as Q235 stainless steel.

[0043] In one example, such as Figure 1 and Figure 2 As shown, the silencing array 3 includes multiple silencing plates 32 distributed along the axial direction of the cylinder 1. The surface of each silencing plate 32 is perpendicular to the axial direction of the cylinder 1. The multiple silencing plates 32 cooperate with the inner wall of the cylinder 1 to form a silencing cavity 31.

[0044] Specifically, after carbon dioxide flows into the silencing array 3, it is subjected to corresponding resistance under the action of the silencing plate 32, and the flow rate decreases. During the flow process, the impact on the cylinder 1 and the silencing plate 32 gradually decreases, and the surge generated is also greatly reduced. Moreover, the sound wave diffraction between multiple silencing plates 32 in the silencing array 3 can cancel out opposite noise sound waves, which can further reduce noise.

[0045] In one example, such as 1, Figure 2 and Figure 4 As shown, multiple through-holes 33 are evenly distributed on the silencing plate 32, and the multiple silencing holes 33 are distributed in a mesh pattern on the surface of the silencing plate 32.

[0046] Specifically, the silencing plate 32 has multiple evenly distributed silencing holes 33 forming a mesh structure. Carbon dioxide can pass through the silencing plate 32 from bottom to top through the silencing holes 33. The silencing holes 33 have sufficient gaps to reduce the radiation area of ​​noise. The mesh-arranged silencing holes 33 have a turbulence effect, which can effectively reduce the flow rate of carbon dioxide, release gas energy, and reduce the vibration, friction and surge of carbon dioxide during the flow process, thereby further reducing noise.

[0047] Furthermore, the sound-absorbing plate 32 can be welded from steel plates using specific welding angles and arrangements.

[0048] Furthermore, the sound-absorbing panel 32 can be covered with sound-absorbing material to further reduce noise.

[0049] In one example, such as Figure 5 As shown, the area of ​​the silencing hole 33 gradually increases along the direction of carbon dioxide flow. That is, the area of ​​the silencing hole 33 in the vertical plane gradually increases from bottom to top, and this design can further improve the silencing effect.

[0050] Furthermore, the silencing hole 33 can be a rhomboid cavity, that is, the opening of the silencing hole 33 in the horizontal plane is rhomboid, and the hole wall of the silencing hole 33 has an inverted trapezoidal structure.

[0051] The sound-absorbing plate 32 is a thin plate with a thickness of 1cm. The sound-absorbing hole 33 is located on the upper surface of the sound-absorbing plate 32 with a side length of 10cm. At this time, the sound-absorbing plate 32 has a better noise reduction effect.

[0052] In one example, such as Figure 1 and Figure 3 As shown, the silencing plate 32 is fixed to the inner wall of the cylinder 1, and a notch 34 is left on one side of it. The two notches 34 of the adjacent silencing plates 32 are alternately distributed on both sides of the cylinder 1.

[0053] Specifically, a notch 34 is provided on one side of the silencing plate 32 to allow carbon dioxide to flow. When carbon dioxide is released to relieve pressure, the carbon dioxide may form dry ice after passing through the silencing array 3 and adhere to the silencing plate 32, potentially causing blockage of the silencing hole 33 and posing a risk of pressure buildup inside the cylinder 1. The notch 34, designed to provide a flow channel for carbon dioxide, can prevent blockage. Furthermore, the two notches 34 of adjacent silencing plates 32 are alternately distributed on both sides of the cylinder 1, so that some of the carbon dioxide flowing through the previous notch 34 will flow along the transverse channel (i.e., the silencing cavity 31) between the two silencing plates 32 to the next notch 34. This can extend the flow path of carbon dioxide, reduce the flow velocity, further improve the noise reduction effect, and at the same time, wash away the dry ice on the silencing plate 32, reducing the probability of blockage of the silencing hole 33.

[0054] In one example, the area of ​​the notch 34 is 1 / 4 to 1 / 2 of the area of ​​the silencing plate 32.

[0055] Furthermore, the area of ​​the notch 34 is 1 / 3 of the area of ​​the silencing plate 32, that is, the area of ​​the notch 34 is 1 / 4 of the radial cross-sectional area of ​​the cylinder 1.

[0056] Furthermore, the silencing array 3 consists of five silencing plates 32 arranged from bottom to top. Each silencing plate 32 has an area of ​​3.7㎡, occupying 3 / 4 of the radial cross-sectional area of ​​the cylinder 1. The notches 34 on the five silencing plates 32 are not aligned and are arranged alternately from bottom to top. This is equivalent to creating a relatively tortuous main flow path for carbon dioxide, while ensuring that sufficient carbon dioxide gas is discharged through the silencing holes to the next silencing plate 32. The interval between adjacent silencing plates 32 is less than 0.5m, which achieves the best effect of gradually reducing noise.

[0057] In one example, such as Figure 1 , Figure 2 and Figure 6 As shown, the noise reduction device also includes a fan 4 located at the outlet end 12 of the cylinder 1, which is used to control the flow rate of carbon dioxide discharged outward.

[0058] Specifically, because the pressure and flow rate of carbon dioxide after passing through the silencing array 3 change significantly and become unstable, a corresponding fan 4 needs to be selected to stabilize the pressure and flow rate of the carbon dioxide after passing through the silencing cavity 31 before discharging it at a specific flow rate. This eliminates the noise caused by the pressure and flow rate changes and ensures that the carbon dioxide flows out to the outlet end 12 of the cylinder 1 at a constant speed and pressure. Furthermore, the fan 4 can control the flow direction of the carbon dioxide after passing through the silencing cavity 31 under the combined effect of pressure difference, directing it to flow out to the outlet end 12 of the cylinder 1, preventing the carbon dioxide from forming denser dry ice and sinking. A forced-flow fan can be used for the fan 4.

[0059] It should be noted that after the carbon dioxide passes through the pressure-reducing nozzle 2, the pressure drops significantly, causing the liquid carbon dioxide to vaporize and absorb less heat, accompanied by the formation of dry ice. Therefore, the silencing cavity 31 contains both gas and dry ice. To prevent dry ice from settling, a fan 4 should be used to quickly exhaust it.

[0060] In one example, such as Figure 1 and Figure 2 As shown, the noise reduction device also includes a dry ice recovery mechanism 5 located outside the cylinder 1, which is connected to the outlet end 12 via a pipe.

[0061] Specifically, the dry ice recovery mechanism 5 is connected to the outlet 12 to achieve the recovery and reuse of carbon dioxide. The dry ice recovery mechanism 5 can capture, recover, and reuse dry ice while allowing carbon dioxide to be discharged smoothly.

[0062] In one example, the dry ice recovery mechanism 5 includes a separation component and an adsorption component (not shown in the figure), the separation component is used to separate gaseous carbon dioxide from dry ice, and the adsorption component is used to collect the dry ice separated by the separation component.

[0063] Specifically, the dry ice recovery mechanism 5 includes a separation component, which can be composed of a dust collection bag connected by metal clips. This component enables the separation of gas and solid, effectively separating gaseous carbon dioxide and dry ice while retaining the solid, high-purity dry ice. The dry ice recovery mechanism 5 also includes an adsorption component, which can be a non-woven fabric made of polymer chips and short fibers. This component effectively collects dry ice and decomposes naturally after use, causing no environmental impact. The dry ice recovery mechanism 5 can be externally equipped with an insulated box to store and protect the dry ice, ensuring that it does not sublimate during storage.

[0064] In one example, such as Figure 1 and Figure 2 As shown, a ladder 7 is provided on the outer side of the cylinder 1 along the axial direction, which facilitates climbing during installation and maintenance.

[0065] Example 2

[0066] The on-site production enhancement technology utilizes carbon dioxide fracturing. This technology requires high-pressure injection of carbon dioxide into the formation, combined with hydraulic fracturing to induce fractures. The injection pressure typically reaches 40-50 MPa, meaning the pressure in the pipeline also reaches 40-50 MPa. Therefore, pressure relief and venting are necessary after the fracturing operation. Since the high-pressure carbon dioxide in the pipeline generates significant noise during this process, this invention designs a noise reduction device. This device, through the coordinated action of a pressure-reducing nozzle 2, a silencer array 3, a blower 4, and a dry ice recovery mechanism 5, reduces noise pollution during pressure relief and minimizes its impact on on-site construction. Simultaneously, it recycles and reuses the dry ice.

[0067] Specifically, after passing through the pressure-reducing nozzle 2, the carbon dioxide undergoes a phase transition, becoming a gas with a pressure of 3-4 MPa; then, the noise from the gas emission is reduced by the turbulence and energy dissipation of the silencer array 3; the gas is then drawn in by the fan 4 and discharged at 70,000 m... 3 The dry ice is discharged at a constant pressure at a rate of / h, while the dry ice recovery mechanism 5 captures and recovers the solid carbon dioxide formed due to pressure changes. This reduces noise pollution during the depressurization process and allows for the recycling and reuse of the dry ice.

[0068] According to comparative measurements from the on-site sound acquisition device, before the noise reduction device was installed, the noise level was approximately between 110 and 135 decibels. Prolonged exposure to this noise would cause prolonged tinnitus or temporary hearing loss. After the noise reduction device was installed, the noise level stabilized in the range of 60 to 70 decibels. Although some noise could still be heard, it no longer significantly affected the normal work of the workers or the rest of the nearby residents.

[0069] In summary, the beneficial effects of the noise reduction device for carbon dioxide fracturing operations of the present invention include at least the following:

[0070] In practical applications, the carbon dioxide fracturing pipeline can be connected to a noise reduction device used for carbon dioxide fracturing operations via a high-pressure venting pipeline. During venting, high-pressure carbon dioxide flows from the venting pipeline into the depressurization nozzle. The pressure of the carbon dioxide is gradually reduced through the depressurization nozzles, whose diameters gradually increase from bottom to top. The lower-pressure carbon dioxide flows towards the silencer array in the depressurization cavity due to the pressure difference and the action of the fan. As the carbon dioxide passes through the silencer array, it releases energy through the layered turbulence caused by multiple specially structured silencer plates, reducing flow velocity and minimizing gas friction, vibration, and surge. Simultaneously, the sound wave diffraction between different silencer plates cancels out noise waves with opposite phases, thus achieving noise reduction. Afterwards, the flow is stabilized by a fan, maintaining the upward flow of carbon dioxide and dry ice, which is then discharged through the outlet. Finally, it flows through a dry ice recovery mechanism to collect and process the dry ice generated by the temperature change of the carbon dioxide.

[0071] Compared to the direct release of carbon dioxide, this invention uses a noise reduction device to greatly reduce the noise emitted when carbon dioxide is discharged from the pipeline, significantly reducing harm to on-site construction workers, nearby residents, and animals. It enables 24-hour construction, avoids disturbing residents, and expands the available construction time and the utilization rate of dry ice.

[0072] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A noise reduction device for carbon dioxide fracturing operations, characterized in that, The noise reduction device includes a cylinder, with an inlet end and an outlet end at the two ends of the cylinder along its axial direction, and a pressure reducing nozzle and a silencer array are provided inside the cylinder along its axial direction. The pressure-reducing nozzle is located at the inlet end and is used to connect to the carbon dioxide emission pipeline. A pressure-reducing cavity is formed between the pressure-reducing nozzle and the inner wall of the cylinder. The silencing array is located in the middle section of the cylinder and a silencing cavity is formed between the silencing array and the inner wall of the cylinder.

2. The noise reduction device for carbon dioxide fracturing operations according to claim 1, characterized in that, The pressure-reducing nozzle has multiple pressure-reducing nozzle holes on its wall, and the diameter of the pressure-reducing nozzle holes increases sequentially from the inlet end to the outlet end.

3. The noise reduction device for carbon dioxide fracturing operations according to claim 1, characterized in that, The silencing array includes multiple silencing plates distributed along the axial direction of the cylinder. The surface of each silencing plate is perpendicular to the axial direction of the cylinder, and the multiple silencing plates cooperate with the inner wall of the cylinder to form the silencing cavity.

4. The noise reduction device for carbon dioxide fracturing operations according to claim 3, characterized in that, The silencing plate has a plurality of through-holes evenly distributed, and the plurality of silencing holes are distributed in a mesh pattern on the surface of the silencing plate.

5. The noise reduction device for carbon dioxide fracturing operations according to claim 4, characterized in that, The area of ​​the silencing hole gradually increases along the direction of carbon dioxide flow.

6. The noise reduction device for carbon dioxide fracturing operations according to claim 3, characterized in that, The sound-absorbing plate is fixed to the inner wall of the cylinder, and a notch is left on one side of it. The two notches of the adjacent sound-absorbing plates are alternately distributed on both sides of the cylinder.

7. The noise reduction device for carbon dioxide fracturing operations according to claim 6, characterized in that, The area of ​​the notch is 1 / 4 to 1 / 2 of the area of ​​the sound-absorbing plate.

8. The noise reduction device for carbon dioxide fracturing operations according to any one of claims 1 to 7, characterized in that, The noise reduction device also includes a fan located at the outlet end of the cylinder, the fan being used to control the outward flow rate of the carbon dioxide.

9. The noise reduction device for carbon dioxide fracturing operations according to claim 8, characterized in that, The noise reduction device also includes a dry ice recovery mechanism located outside the cylinder, which is connected to the outlet end via a pipe.

10. The noise reduction device for carbon dioxide fracturing operations according to claim 9, characterized in that, The dry ice recovery mechanism includes a separation component and an adsorption component. The separation component is used to separate gaseous carbon dioxide from dry ice, and the adsorption component is used to collect the dry ice separated by the separation component.

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