Carbon dioxide safety relief device and process
The carbon dioxide safety release device, which combines an air introduction system and a vortex tube, uses a venturi tube and a vortex tube to change the phase change temperature of CO2 and forms a low-pressure zone through a baffle tube to accelerate emission. This solves the problem of safe release of CO2 in the pipeline, achieves high-speed and safe release of CO2, and avoids the formation of dry ice and the accumulation of heavy gas.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-12-19
- Publication Date
- 2026-06-23
AI Technical Summary
Existing technologies lack safe release equipment for large-scale CO2 transport pipelines, which makes it easy for CO2 to form dry ice during the release process, damaging pipelines and auxiliary equipment. Furthermore, heavy gas tends to accumulate in low-lying areas, endangering human safety.
A carbon dioxide safety release device that combines an air introduction system with a vortex tube changes the CO2 phase change temperature through the Venturi tube and vortex tube structure, and utilizes pressure energy to convert it into internal energy. Combined with the baffle tube, it forms a low-pressure zone to accelerate emission, avoiding the formation of dry ice and the accumulation of heavy gas.
This method enables high-speed and safe CO2 release, avoids dry ice formation and heavy gas accumulation, reduces pipeline damage, and improves the safety of the release process.
Smart Images
Figure CN122258301A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of carbon dioxide safe release technology, specifically relating to a carbon dioxide safe release device and process. Background Technology
[0002] Carbon capture, utilization, and storage (CCUS) technology is an effective way to achieve global carbon dioxide emission reduction. CO2 pipeline transportation is an important part of CCUS technology. Studies have shown that supercritical transport is the most economical method. To prevent overpressure accidents in pipelines, CO2 pipelines usually need to be artificially vented.
[0003] CO2 has a high Joule-Thomson coefficient. During CO2 venting, the pipeline and venting device are prone to significant temperature drops and dry ice blockage due to the throttling expansion effect, which may lead to brittle fracture of the venting pipeline. The low-temperature CO2 with heavy gas characteristics released during the venting process can easily form high-concentration areas in low-lying areas, causing asphyxiation, coma, or even death to humans.
[0004] Currently, there is a lack of research and development on safe venting equipment for large-scale CO2 transport pipelines. There is an urgent need to develop a safe and efficient carbon dioxide venting process and device to reduce the formation of dry ice during the CO2 venting process, reduce damage to pipelines and auxiliary equipment, release CO2 to a higher area, and reduce the accumulation of heavy gas. Summary of the Invention
[0005] (a) Technical problems to be solved
[0006] The purpose of this invention is to provide a carbon dioxide safe release process and apparatus for achieving high-speed and safe release of carbon dioxide. By utilizing high-pressure carbon dioxide throttling to create a low-pressure zone to introduce air, and by using a vortex tube to heat the released carbon dioxide, the formation of dry ice is effectively suppressed. Furthermore, the high-speed release system achieves rapid carbon dioxide release, reducing the accumulation of heavy gas and achieving the goal of safe release.
[0007] (II) Technical Solution
[0008] To achieve the above objectives, according to a first aspect of the present invention, a carbon dioxide safety release device is provided. In this invention, the phase transition temperature of the released gas is changed by introducing air, and the pressure of the released gas is fully utilized to convert a portion of the pressure energy into internal energy, thereby increasing the temperature of the released gas.
[0009] The carbon dioxide safety release device of the present invention includes:
[0010] The air introduction system, which is a venturi tube structure, is used to introduce air into the CO2 released in the first part to form a CO2 / N2 mixture, thereby reducing the phase change temperature of the mixture (compared to pure CO2 gas).
[0011] The first-stage heating system is a vortex tube, which is used to receive the CO2 / N2 mixture discharged from the air introduction system and convert the pressure energy of the first part of the high-pressure CO2 into internal energy to increase the temperature of the CO2 / N2 mixture.
[0012] The second-stage heating system, which is a venturi tube structure, is used to mix the CO2 released in the second part with the heated CO2 / N2 mixture to increase the temperature of the CO2 released in the second part.
[0013] Furthermore, the carbon dioxide safety release device of the present invention also includes: a CO2 gas exhaust system, which is a tubular structure connected to a high-pressure CO2 pipeline, used to release high-pressure CO2 gas from the high-pressure CO2 pipeline and divide the high-pressure CO2 gas into two paths.
[0014] Furthermore, in the above technical solution, the air introduction system is a Venturi tube structure. The first portion of the released CO2 enters through the first inlet of the air introduction system. As the cross-section gradually decreases, the CO2 pressure decreases and the flow velocity increases, creating a vacuum within the throat. This draws surrounding air into the second inlet of the air introduction system. The air and CO2 mix at the throat and flow together into the diffusion chamber. Then, the cross-section continuously expands, the flow velocity decreases, and the pressure increases. This is primarily due to the unique properties of CO2, which readily undergoes a phase change. After mixing with air, the mixture consists of CO2 and N2, lowering the temperature at which the phase change occurs and facilitating the subsequent conversion of the pressure energy of the mixture into internal energy, thus preventing the phase change of the cold fluid.
[0015] Furthermore, in the above technical solution, the vortex tube of the first-stage heating system is a structure well-known to those skilled in the art. A typical vortex tube includes: a heat pipe, a vortex chamber, a spiral orifice plate, a spiral guide groove, a control valve, a cold pipe, and a high-pressure gas inlet. The CO2 / N2 mixed gas discharged from the air intake system outlet enters the heat pipe through the spiral guide groove of the spiral orifice plate in the vortex chamber. The mixed gas generates vortices within the heat pipe. During high-speed rotation, after vortex transformation, it separates into two airflows of unequal temperatures. The airflow in the central part has a lower temperature, while the airflow in the outer part has a higher temperature. The hotter mixed gas flows to the outer circle, while the colder mixed gas flows to the inner circle. At the same time, there is a control valve at the end of the heat pipe to prevent this, so only hot gas is ejected from the heat pipe outlet. The remaining cold gas is blocked and bounces back in the opposite direction, flowing towards the cold pipe outlet. Moreover, the greater the input gas pressure, the greater the temperature difference between the hot and cold gas.
[0016] Furthermore, in the above technical solution, the vortex chamber has a spiral perforated plate installed inside and is connected to a high-pressure gas inlet, allowing the mixed gas to enter the heat pipe tangentially through the spiral perforated plate.
[0017] Furthermore, in the above technical solution, the control valve is installed at the tail end of the heat pipe and is mainly used to separate the hot and cold gases. Since the hot gas moves in a spiral motion on the heat pipe wall and the cold fluid moves in a spiral motion in the center of the heat pipe, the control valve can prevent the cold gas from flowing out of the heat pipe outlet and change its direction of movement so that it flows out of the cold pipe outlet.
[0018] Furthermore, in the above technical solution, the second-stage heating system is a Venturi tube. Another portion of the released CO2 enters from the first inlet of the second-stage heating system. As the cross-section gradually decreases, the pressure of the CO2 fluid decreases and the flow velocity increases. At this time, a vacuum is generated in the throat, which draws the hot gas discharged from the heat pipe of the first-stage heating system into the throat of the second-stage heating system through the second inlet. As this portion of CO2 and hot gas flow into the diffusion cavity together, the cross-section continuously expands, the flow velocity decreases, and the pressure increases.
[0019] Furthermore, the above technical solution also includes a carbon dioxide accelerated emission unit, which includes:
[0020] The intake unit is used to introduce the CO2 gas discharged from the second-stage heating system into the acceleration baffle tube. It is a pipe (which can be circular) and its inlet is connected to the diffusion chamber of the second-stage heating system.
[0021] The buffer zone has an opening at its bottom that connects to the outlet of the aforementioned air intake unit; it also has an opening at its top for using the CO2 discharged from the second-stage heating system to heat the CO2 fluid at the bottom of the second-stage baffle tube.
[0022] The system consists of several stages of baffles, which are generally arranged vertically. The lower opening of the first-stage baffle is connected to the outlet of the buffer zone (i.e., the upper opening), and the upper outlet of the first-stage baffle is connected to the upper inlet of the second-stage baffle. The lower outlet of the second-stage baffle is connected to the upper outlet of the third-stage baffle. The outlet of the third-stage baffle is connected to the atmosphere or a downstream device.
[0023] Furthermore, the gas discharged from the second-stage heating system is deflected and accelerated by the acceleration baffle tube before being discharged into the atmosphere.
[0024] Furthermore, in the above technical solution, the CO2 discharged from the second-stage heating system needs to pass through the buffer zone before entering the first-stage baffle tube.
[0025] Furthermore, in the above technical solution, the length of the buffer zone is approximately three times the diameter of the circular pipe of the air intake unit, the width is equivalent to the diameter of the circular pipe of the air intake unit, and the height is equivalent to the diameter of the circular pipe of the air intake unit.
[0026] Furthermore, the accelerating baffles are parallel pipes of the same diameter, roughly equivalent to the diameter of the circular pipe in the intake unit. They are typically arranged in three stages, with a height approximately 3 to 5 times the diameter of the circular pipe in the intake unit. The first-stage baffle is connected to the opening at the upper right of the buffer zone. When hot CO2 enters the accelerating emission unit, it passes through the buffer zone and enters the first-stage baffle. Upon reaching the top of the first baffle, its movement is obstructed, causing it to accumulate and gradually increase in pressure, exceeding the pressure at the bottom. Driven by this pressure difference, the CO2 accelerates to the top of the first-stage baffle, which is connected to the second-stage baffle. The CO2 continues to move to the bottom of the second-stage baffle. Upon reaching this point, the CO2 exchanges heat with the hot CO2 that just entered the accelerating emission unit in the buffer zone, causing its temperature to rise and its density to decrease, forming a new low-pressure zone. This creates a pressure difference with the high-pressure zone at the top of the first-stage baffle, allowing CO2 to flow rapidly from the top of the first-stage baffle to the bottom of the second-stage baffle. This also allows CO2 to reach the bottom of the second-stage baffle tube at a greater velocity, thus enabling CO2 to be discharged quickly from the third-stage baffle tube.
[0027] According to a second aspect of the invention, the invention also provides a method for the safe release of carbon dioxide, wherein the aforementioned safe release device is used.
[0028] Compared with the prior art, the present invention has the following beneficial effects:
[0029] 1) The carbon dioxide safety release device of this invention, to avoid the problem of pure CO2 easily freezing at low temperatures, introduces air through a Venturi tube, thereby forming a CO2 / N2 mixture, solving the problems of pure CO2 easily undergoing phase change and large temperature drop. The mixture enters the vortex tube at high speed, and then tangentially enters the heat pipe through a spiral orifice plate inside the vortex tube. The hot fluid is separated by a control valve to heat the remaining CO2. The pressure energy of CO2 itself is used to achieve the introduction of air and the heating of the gas itself, avoiding the formation of dry ice during the release process.
[0030] 2) In the CO2 accelerated emission unit, the present invention controls the temperature of the mixed gas by setting a baffle tube to form a relatively low-pressure zone and a high-pressure zone, thereby forming an accelerated emission channel, which accelerates the emission of CO2 and avoids the CO2 heavy gas effect.
[0031] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description
[0032] Figure 1 This is a schematic diagram of the carbon dioxide safety release device of the present invention.
[0033] Figure 2 This is a schematic diagram of the first-stage heating system of the present invention.
[0034] Figure 3 This is a cross-sectional view (AA) of the first-stage heating system of the present invention.
[0035] Figure 4 This is a schematic diagram and a schematic diagram of the CO2 accelerated emission unit of the present invention.
[0036] Figure 5 This is a top view of the CO2 accelerated emission unit of the present invention.
[0037] Figure 1-4 Explanation of the numerical markings in the text:
[0038] 1-High-pressure CO2 pipeline, 2-Second-stage heating system, 3-CO2 accelerated emission unit, 4-Air introduction system, 5-Second inlet of air introduction system, 6-First-stage heating system, 7-Second inlet of second-stage heating system, 8-Diffuser chamber, 9-First inlet of air introduction system, 10-Throat, 11-First inlet of second-stage heating system, 12-Throat, 13-Diffuser chamber, 31-First-stage baffle tube, 32-Second-stage baffle tube, 33-Third-stage baffle tube, 34-CO2 accelerated emission unit discharge port, 35-Inlet unit, 36-Buffer zone, 61-Control valve, 62-High-pressure gas inlet, 63-Vortex chamber, 64-Helical orifice plate, 65-Heat pipe, 66-Cold pipe, 67-Helical guide groove. Detailed Implementation
[0039] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.
[0040] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.
[0041] In this document, for ease of description, spatial relative terms such as “lower left,” “upper right,” “lower,” “above,” “upper,” “up,” “lower,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as being “lower left” to another element or feature would be oriented “lower right” to that element or feature. Thus, the exemplary term “lower left” can encompass both lower left and lower right orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.
[0042] In this document, the terms "first," "second," "third," etc., are used to distinguish several different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," "third," etc., can also be used interchangeably.
[0043] Example 1
[0044] The carbon dioxide safety release device of the present invention changes the phase change temperature of the released gas by introducing air and makes full use of the pressure of the released gas to convert a portion of the pressure energy into internal energy, thereby increasing the temperature of the released gas.
[0045] Combined with appendix Figure 1-5 The carbon dioxide safety release device includes: an air introduction system 4, which is a Venturi tube structure, used to introduce air into the first part of the released CO2 to form a CO2 / N2 mixed gas, which greatly reduces the phase change temperature of the mixed gas compared to pure CO2 gas; a first-stage heating system 6, which adopts a vortex tube structure, used to convert the pressure energy of the first part of the released CO2 into internal energy, thereby increasing the temperature of the CO2 / N2 mixed gas; and a second-stage heating system 2, which is a Venturi tube structure, used to mix the first part of the released CO2 with the heated CO2 / N2 mixed gas, thereby increasing the temperature of the second part of the released CO2.
[0046] The air introduction system 4 is a venturi tube, including a first inlet 9, a second inlet 5, a throat 10, and a diffuser 8. The first portion of the released CO2 enters through the first inlet 9 of the air introduction system 4. As the cross-section gradually decreases, the CO2 pressure decreases and the flow velocity increases. This creates a vacuum within the throat 10, causing surrounding air to be drawn into the second inlet 5. The air and CO2 mix at the throat 10 and then flow together into the diffuser 8. The cross-section then expands, the flow velocity decreases, and the pressure increases. This is primarily due to the unique properties of CO2, which readily undergoes a phase change. After mixing with air, the gas mixture is CO2 / N2, thus lowering the temperature at which the phase change occurs and facilitating the subsequent conversion of the pressure energy of the mixture into internal energy, preventing a cold fluid phase change.
[0047] like Figure 2 As shown, the first-stage heating system 6 adopts a vortex tube structure, specifically including: a heat pipe 65, a vortex chamber 63, a spiral perforated plate 64, a spiral guide groove 67, a control valve 61, a cold pipe 66, and a high-pressure gas inlet 62. The vortex tube has no moving parts and is a hollow tubular structure. The vortex chamber 63 is arranged inside, and a spiral perforated plate 64 is provided on the vortex chamber, with spiral guide grooves 67 arranged on the spiral perforated plate. The two ends are the heat pipe 65 and the cold pipe 66, respectively, with a control valve 61 at the end of the heat pipe 65. During operation, compressed gas enters the vortex tube 63 tangentially at a very high speed. When the airflow rotates at high speed inside the vortex tube, it is separated into two parts of airflow with unequal temperatures after vortex transformation; the airflow in the central part has a lower temperature, while the airflow in the outer part has a higher temperature. Specifically, the CO2 / N2 mixed gas enters the heat pipe 65 through the spiral guide groove 67 of the spiral perforated plate 64 of the vortex chamber 63. The mixed gas generates vortices within the heat pipe 65. During high-speed rotation, after vortex transformation, it separates into two gas streams of unequal temperatures: the gas stream in the center is colder, while the gas stream in the outer layer is hotter. The hotter mixed gas flows towards the outer ring, while the colder mixed gas flows towards the inner ring. Simultaneously, a control valve 61 at the end of the heat pipe 65 prevents this, so only hot gas exits from the outlet of the heat pipe 65. The remaining cold gas, after being blocked, bounces back in the opposite direction and flows towards the outlet of the cold pipe 66. Furthermore, the greater the input gas pressure, the greater the temperature difference between the hot and cold gas.
[0048] The vortex chamber 63 is equipped with a spiral perforated plate 64 and is connected to the high-pressure gas inlet 62. The spiral perforated plate 64 has a spiral guide groove 67, through which the mixed gas can enter the heat pipe 65 tangentially.
[0049] In the above technical solution, the control valve 61 is installed at the tail end of the heat pipe 65, mainly used to separate hot and cold gases. Since the hot gas moves in a spiral motion along the wall of the heat pipe 65, and the cold fluid moves in a spiral motion at the center of the heat pipe 65, the control valve 61 can prevent the cold gas from flowing out of the outlet of the heat pipe 65, changing its direction of motion and causing it to flow out from the outlet of the cold pipe 66. The control valve 61 is a common valve in the art, generally with a conical structure.
[0050] In the above technical solution, the second-stage heating system 2 is a venturi tube structure. The second part of the released CO2 enters from the first inlet 11 of the second-stage heating system 2. As the cross-section gradually decreases, the pressure of the CO2 fluid decreases and the flow rate increases. At this time, a vacuum is generated in the throat tube 12, which draws the hot gas discharged from the heat pipe 65 of the first-stage heating system 6 into the throat tube 12 of the second-stage heating system 2 through the second inlet 7 of the second heating system. This part of CO2 and hot gas flow into the diffusion cavity 13 together, where the cross-section continuously expands, the flow rate decreases, and the pressure increases.
[0051] Example 2
[0052] The carbon dioxide safe release device of the present invention preferably includes a CO2 accelerated emission unit 3.
[0053] Combination Figure 4 The CO2 acceleration emission unit includes an intake unit 35, which is supplied with gas through a second-stage heating system 2; a buffer zone 36, which uses the CO2 discharged from the second-stage heating system 2 to heat the CO2 fluid at the bottom of the second-stage baffle tube 32; and acceleration baffle tubes 31-33, which can deflect and accelerate the gas discharged from the second-stage heating system before discharging it into the atmosphere.
[0054] like Figure 4 As shown, the front view of buffer zone 36 is rectangular, with an opening in its lower left corner that connects to the outlet of the aforementioned air intake unit; and a circular opening in its upper right corner, used to heat the CO2 fluid at the bottom of the second-stage baffle tube using the CO2 discharged from the second-stage heating system.
[0055] The CO2 discharged from the second-stage heating system needs to pass through buffer zone 36 before entering the first-stage baffle tube 31. The acceleration baffle tubes 31-33 are parallel pipes of the same diameter.
[0056] When hot CO2 enters the accelerated emission unit 3, it flows through the buffer zone 36 and into the first-stage baffle tube 31. Upon reaching the top of the first baffle tube 31, its movement is obstructed, causing it to accumulate and gradually increase in pressure, exceeding the pressure at the bottom. Driven by this pressure difference, the CO2 accelerates to the top of the first-stage baffle tube 31. The CO2 continues to the bottom of the second-stage baffle tube 32. Upon reaching this point, the CO2 exchanges heat with the hot CO2 that just entered the accelerated emission unit 3 in the buffer zone 36, increasing its temperature and decreasing its density, forming a new low-pressure zone. This low-pressure zone at the bottom of the second-stage baffle tube 32 and the high-pressure zone at the top of the first-stage baffle tube 31 create a pressure difference, allowing CO2 to flow rapidly from the top of the first-stage baffle tube 31 to the bottom of the second-stage baffle tube 32. This also gives the CO2 a greater velocity at the bottom of the second-stage baffle tube 32, enabling it to be quickly discharged from the third-stage baffle tube 33, achieving safe carbon dioxide release.
Claims
1. A carbon dioxide safety release device, characterized in that, include: The air introduction system, which is a venturi tube structure, is used to introduce air into the CO2 released in the first part to form a CO2 / N2 mixed gas, thereby reducing the phase change temperature of the mixed gas. The first-stage heating system is a vortex tube, which is used to receive the CO2 / N2 mixture discharged from the air introduction system and convert the pressure energy of the first part of the high-pressure CO2 into internal energy to increase the temperature of the CO2 / N2 mixture. The second-stage heating system, which is a venturi tube structure, is used to mix the CO2 released in the second part with the heated CO2 / N2 mixture to increase the temperature of the CO2 released in the second part.
2. The carbon dioxide safety release device according to claim 1, characterized in that, Also includes: The CO2 gas extraction system is a tubular structure connected to a high-pressure CO2 pipeline, used to release high-pressure CO2 gas from the high-pressure CO2 pipeline and to divide the high-pressure CO2 gas into two paths.
3. The carbon dioxide safety release device according to claim 1, characterized in that, The air introduction system includes a contraction chamber, i.e., a first inlet of the air introduction system, a throat, and a diffusion chamber, and a second inlet of the air introduction system is connected to the throat.
4. The carbon dioxide safety release device according to claim 1, characterized in that, The vortex tube includes a heat pipe, a vortex chamber, a spiral orifice plate, a spiral guide groove, a control valve, a cold pipe, and a high-pressure gas inlet.
5. The carbon dioxide safety release device according to claim 4, characterized in that, The vortex chamber is equipped with a spiral perforated plate and is connected to a high-pressure gas inlet. The mixed gas enters the heat pipe tangentially through the spiral perforated plate.
6. The carbon dioxide safety release device according to claim 4, characterized in that, It also includes a carbon dioxide accelerated emission unit, which comprises: The intake unit is used to introduce the CO2 gas discharged from the second-stage heating system into the acceleration baffle tube. It is a pipe with its inlet connected to the diffusion chamber of the second-stage heating system. The buffer zone has an opening at its bottom that connects to the outlet of the aforementioned air intake unit; it also has an opening at its top for using the CO2 discharged from the second-stage heating system to heat the CO2 fluid at the bottom of the second-stage baffle tube. The system comprises several stages of baffle tubes, which are arranged vertically. The lower opening of the first-stage baffle tube is connected to the outlet of the buffer zone, and the upper outlet of the first-stage baffle tube is connected to the upper inlet of the second-stage baffle tube. The lower outlet of the second-stage baffle tube is connected to the upper outlet of the third-stage baffle tube. The outlet of the third-stage baffle tube is connected to the atmosphere or a downstream device.
7. The carbon dioxide safety release device according to claim 6, characterized in that, The acceleration baffles are parallel pipes of the same diameter.
8. The carbon dioxide safety release device according to claim 6, characterized in that, The buffer zone is three times the diameter of the circular intake pipe, and its width and height are equivalent to the diameter of the circular intake pipe.
9. The carbon dioxide safety release device according to claim 7, characterized in that, The diameter of the acceleration baffle is similar to the diameter of the circular pipe of the intake unit, and the height of the acceleration baffle is approximately 3 to 5 times the diameter of the intake unit pipe.
10. The present invention also provides a method for the safe release of carbon dioxide, characterized in that, The safety relief device according to any one of claims 1-9 is applied.