Medium-temperature supercritical carbon dioxide anti-freezing and anti-blocking safety valve

Abstract

The application provides a medium-temperature supercritical carbon dioxide anti-freezing and anti-blocking safety valve, which comprises an inner valve body, an outer valve body, a flow guide plate, a support ring, a guide rod, a spring, a valve core, a valve seat and a connecting pipe. In the application, the valve core is pressed and matched with the sealing surface of the valve seat under the combined action of the self weight and the top spring force, so that the leakage of gas flow is prevented. The outer circular surface of the valve core is provided with a spiral groove, and the outer circular surface of the valve core is matched and installed with the inner hole of the inner valve body. The surface of the inner hole of the inner valve body is provided with a limiting step and a circumferential flow storage groove, and the flow storage groove is provided with uniformly distributed tangential through holes, which are connected with the inner valve body and the outer valve body. The outer wall of the outer valve body is circumferentially provided with the flow guide plate and the support ring. The outer surface of the safety valve device is provided with a heat preservation coating, which prevents the heat exchange between the valve and the external environment. The spiral groove on the outer circular surface of the valve core, the flow storage groove and the tangential through holes of the inner valve body, the flow guide plate of the outer valve body and the outer heat preservation coating of the valve body are designed to reduce or avoid the deposition and blocking of the solid phase medium in the pressure relief process of the medium-temperature supercritical carbon dioxide gas, so as to ensure the safe operation of the container.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engineering machinery, and relates to a medium-temperature supercritical carbon dioxide anti-freezing and anti-blocking safety valve. BACKGROUND

[0002] Supercritical carbon dioxide gas with a temperature of 150-200 DEG C and a pressure of 7-20 MPa is widely applied in the industrial field. However, due to the significant pressure reduction refrigeration effect of supercritical CO2 gas, a safety valve used for the safety protection of a supercritical CO2 gas container is prone to be frozen and blocked during pressure relief, and the container cannot be safely relieved. At present, a combined device of a rupture disc and a valve is generally used to protect the safety relief of the container. However, the combined device needs to be replaced with a new rupture disc in time after the rupture disc is ruptured, which brings great inconvenience to the application due to the frequent disassembly and assembly of the rupture disc. Therefore, it is of great engineering significance to design a supercritical CO2 safety valve which is simple in structure, safe and reliable, and convenient to operate. SUMMARY

[0003] The embodiment of the present application provides a medium-temperature supercritical CO2 anti-freezing and anti-blocking safety valve, which can protect the safety relief of a supercritical CO2 container.

[0004] The medium-temperature supercritical CO2 anti-freezing and anti-blocking safety valve device provided by the embodiment of the present application comprises a valve seat, a valve core, a spring, a guide rod, an inner valve body, an outer valve body, a sealing element, a fastener and a connecting pipe, wherein,

[0005] One end flange of the valve seat is fixedly connected with the supercritical CO2 container, and the other end flange is fixedly connected with the flange of the inner valve body. A through hole is formed in the center of the valve seat, which is a gas flow channel for pressure relief of the supercritical CO2 container. A sealing surface matched with the lower end of the valve core is processed on the upper part of the through hole.

[0006] The valve core is installed in cooperation with the inner valve body. A helical groove is processed on the outer circular surface of the valve core, and a sealing surface is processed on the lower part of the valve core to cooperate with the valve seat. The upper end surface of the valve core is fixedly connected with the guide rod. The spring is installed on the guide rod. One end of the spring is in contact with the spring seat on the guide rod, and the other end is in contact with the top end surface of the inner valve body.

[0007] A circumferential flow storage groove is processed on the inner hole surface of the inner valve body. A plurality of tangential through holes are uniformly distributed in the flow storage groove. The direction of the tangential through holes is consistent with the rotation direction of the helical groove on the surface of the valve core. A limiting step is processed on the inner hole surface of the inner valve body to limit the lift of the valve core.

[0008] The outer valve body is fixedly connected with the inner valve body, and the end is sealed by the sealing element; the split annular flow guide plate is fixedly installed on the inner hole wall surface of the outer valve body; the inner diameter of the first annular flow guide plate is in contact sealing with the outer circular wall surface of the inner valve body, and the outer diameter is kept a certain radial gap with the inner hole wall surface of the outer valve body; the lower part of the flow guide plate is provided with a flow guide slot on the support ring; the inner diameter of the second annular flow guide plate is kept a certain radial gap with the outer circular wall surface of the inner valve body, and the outer diameter is in contact sealing with the inner hole wall surface of the outer valve body; the rest of the flow guide plates are installed according to the requirements of the first and second flow guide plates.

[0009] The surfaces of the valve seat, the inner valve body, the outer valve body, the connecting pipe and the fixing element which are in contact with the external environment are coated with a heat preservation coating.

[0010] The lower sealing surface of the valve core cooperates with the sealing surface of the valve seat to seal, and the safety valve is in a closed state without exhaust; when the valve core is lifted by the supercritical CO2 gas, the central through hole of the valve seat and the outer circular surface screw groove of the valve core are communicated to form an exhaust passage for the supercritical CO2 gas; after the supercritical CO2 leaves the screw groove of the valve core, it enters the annular flow storage groove of the inner valve body, flows out from the tangential through hole in the flow storage groove, and enters the outer valve body; the supercritical CO2 gas in the outer valve body is folded back and rises along the flow guide plate, and finally flows out from the top connecting pipe of the outer valve body.

[0011] Optionally, the first and third flow guide plates of the outer valve body are provided with flow guide slots on the support rings.

[0012] Optionally, the top of the outer valve body is fixedly connected with the end cover through bolts.

[0013] Optionally, the lower flange of the valve seat is sealed with the supercritical CO2 container through an O-ring, the upper flange end face of the valve seat is sealed with the inner valve body through a sealing ring, the connecting end part of the outer valve body and the inner valve body is sealed through a sealing gasket, and the connecting part of the top of the outer valve body and the connecting pipe is sealed through a sealing gasket.

[0014] Optionally, the inner hole wall surface of the inner valve body has at least two annular flow storage grooves, and at least three tangential through holes are uniformly distributed in the flow storage grooves; the diameter of the tangential through hole is not greater than the width of the flow storage groove.

[0015] Optionally, at least two split annular flow guide plates are installed on the inner hole wall surface of the outer valve body; the split annular flow guide plate is composed of at least three fan-shaped ring plates.

[0016] It can be seen that the application adopts a small lead screw groove channel to prolong the leakage channel of CO2 gas flow, and the supercritical CO2 gas flow pressure energy is converted into friction heat in the rotating shear flow, effectively reducing the cooling effect of the supercritical CO2 pressure reduction process, preventing the flow channel from being blocked due to "icing"; secondly, the screw groove and the circumferential tangential through hole design enhances the outflow ability of the gas flow and the possible small solid-liquid phase particles contained in the gas flow by the centrifugal force generated by the gas flow rotation, preventing the solid-liquid particles from being retained in the gas channel; the valve body is coated with a heat preservation coating on the outside to prevent heat dissipation and cooling to the environment during the gas flow leakage process, further reducing the "icing" blocking effect of the supercritical CO2 gas. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The drawings are not intended to be restrictive in any way. In the drawings:

[0018] Figure 1 A medium-temperature supercritical carbon dioxide anti-freezing and anti-blocking safety valve structure provided by the embodiment of the application is shown in the figure.

[0019] Figure 2 A valve body limiting step, flow storage groove and tangential through hole arrangement provided by the embodiment of the application is shown in the figure.

[0020] Figure 3 A valve core outer circular surface screw groove flow channel and lower end sealing surface provided by the embodiment of the application is shown in the figure. DETAILED DESCRIPTION

[0021] Figure 1 A medium-temperature supercritical carbon dioxide anti-freezing and anti-blocking safety valve structure provided by the embodiment of the application is shown in the figure, which includes an outer valve body 1, a fixing piece 2, a connecting pipe 3, an inner valve body 4, a spring 5, a guide rod 6, a valve core 7, a sealing ring 8 and a valve seat 9.

[0022] The specific implementation of the safety valve of the application will be described below in combination with Figure 1 , Figure 2 and Figure 3 .

[0023] The cylindrical surface of the valve core 7 is processed with a screw groove 701, and the lower end sealing surface 702 of the valve core 7 cooperates with the upper end sealing surface of the central through hole of the valve seat 9 to seal and prevent the gas in the container from leaking. The outer circle of the valve core 7 cooperates with the inner hole of the inner valve body 4, and the cooperation gap is not more than 0.2 mm. The upper end of the valve core 7 is fixedly connected with the guide rod 6, and the other end of the guide rod 6 cooperates with the guide hole 403 at the top of the inner valve body 4 to slide. The connection length of the guide rod 6 and the valve core 7 can be adjusted, and then the compression amount of the spring 5 installed on the guide rod can be adjusted. The number, rotation direction and geometric size of the screw groove 701 on the outer circular wall surface of the valve core are not limited in the application.

[0024] The inner valve body 4 is fixedly connected with the valve seat 9, and the inner hole surface of the inner valve body 4 is limited by a limiting step 401, which limits the height of the valve core 7 rising therein. A flow storage groove 404 is formed on the inner hole surface of the inner valve body 4, and a plurality of tangential through holes 402 are formed in the flow storage groove. The direction of the tangential through holes 402 is consistent with the rotation direction of the screw groove 701 on the surface of the valve core 7. The number of the flow storage grooves 404 on the inner cylindrical surface of the inner valve body 4 is not less than 2, and the number of the tangential through holes in the flow storage grooves is not less than 3. The size of the flow storage grooves and the tangential through holes is not limited.

[0025] The outer valve body 1 is composed of an outer valve body cover 101, a flow guide plate 102 and a support ring 103. The flow guide plate 102 is composed of a plurality of ring petals. From the bottom of the outer valve body 1, the first and third flow guide plates have a certain gap between the outer diameter and the inner hole wall surface of the outer valve body 1, and the inner diameter is in close contact with the outer cylindrical wall surface of the inner valve body. The second flow guide plate is in close contact with the inner cylindrical wall surface of the outer valve body 1, and a certain gap is reserved between the inner diameter and the outer cylindrical wall surface of the inner valve body. The support ring 103 under the first and third flow guide plates 102 is provided with a flow guide slit, so that the gas flow at the lower part of the flow guide plate can rise to the upper part of the flow guide plate. The radial gap size between the flow guide plate and the inner and outer valve bodies and the size of the flow guide slit of the support ring at the lower part of the flow guide plate are not limited.

[0026] The surfaces of the valve seat 9, the inner valve body 4, the outer valve body 1 and the connecting pipe 3, which are in contact with the external environment, are uniformly coated with a heat preservation coating to prevent heat exchange between the gas flow and the external environment.

[0027] The working principle of the medium temperature supercritical carbon dioxide anti-freezing and anti-blocking safety valve provided by the embodiment of the present application is as follows.

[0028] When the supercritical CO2 gas with a temperature of 150-200℃ and a pressure of 7-20MPa in the container exceeds the safety pressure of the container, the gas flow overcomes the spring force acting on the valve core 7 and the gravity of the valve core 7, and lifts the valve core 7. The valve core 7 rises, and the lower end sealing surface 702 of the valve core and the sealing surface of the valve seat form a gas flow channel. The gas flow passes through the sealing gap from the through hole of the valve seat, and spirally flows upward in the screw groove 701 on the surface of the valve core. The strong gas flow rotation sharply rubs against the wall surface of the screw groove, generating heat, which alleviates the cooling effect of the gas flow pressure reduction and expansion, and prevents the gas flow from “icing” and blocking the gas passage. The rising gas flow leaves the screw groove, enters the flow storage groove 404, and flows into the outer valve body 1 through the tangential through holes 402 in the flow storage groove. The gas flow entering the outer valve body flows along the flow guide plate 102, continues to convert the kinetic energy of the gas flow into heat energy, and finally flows to the outside through the connecting pipe 3 at the top of the outer valve body. When the gas pressure in the CO2 container decreases, the gas flow pressure cannot support the valve core 7, and the valve core 7 falls down. The sealing surfaces of the valve core 7 and the valve seat 9 are in close contact with each other, which blocks the outward flow of the gas flow in the container.

[0029] It should be noted that the above embodiments are used to explain the present application, but are not limiting.

Claims

1. A medium-temperature supercritical carbon dioxide antifreeze and anti-clogging safety valve, wherein the medium-temperature supercritical carbon dioxide antifreeze and anti-clogging safety valve comprises an outer valve body, a guide plate, a support ring, an inner valve body, a guide rod, a spring, a valve core, a valve seat, a seal, and a connecting pipe, wherein, The valve seat bottom flange is fixedly connected to the container. A through hole is opened in the center of the valve seat, and a sealing surface is machined at the upper end of the through hole. The inner valve body is fixedly connected to the upper flange of the valve seat. A flow storage groove is machined on the inner circular surface of the inner valve body, and several tangential through holes are present in the flow storage groove along the thickness direction of the inner valve body. The outer circle of the valve core mates with the inner hole of the inner valve body, allowing the valve core to move up and down along the axis of the inner valve body. A sealing surface is machined at the lower end of the valve core, mates with the sealing surface of the valve seat end face, and provides a seal. A spiral groove is machined on the cylindrical surface of the valve core, and the upper end face of the cylinder is connected to the guide rod. The other end of the guide rod is placed in the inner hole at the top of the inner valve body. A spring is mounted on the guide rod, and one end of the spring is connected to the spring on the guide rod. The valve seat is connected to the inner valve body, and the other end is connected to the top end face of the inner valve body. The outer valve body is threaded to the inner valve body, and the connection end is sealed. The outer valve body is threaded to the connecting pipe and is fastened and sealed. The outer surfaces of the valve seat, the inner valve body, the outer valve body, and the connecting pipe are all coated with heat insulation coating. The air inlet hole in the middle of the valve seat is connected to the container. When the gas pressure in the container exceeds the safe pressure of the container, the valve core is pushed open by the gas in the container. The gas flows spirally upward along the spiral groove on the outer circumference of the valve core, enters the storage tank of the inner valve body, flows out from the tangential through hole of the storage tank of the inner valve body, enters the outer valve body, continues to flow along the guide plate of the outer valve body, and is discharged from the connecting pipe at the top of the outer valve body.

2. The intermediate-temperature supercritical carbon dioxide antifreeze and anti-clogging safety valve according to claim 1, characterized in that, The outer circle of the valve core is fitted with the inner hole of the inner valve body to ensure that the valve core remains coaxial with the inner hole of the inner valve body when it moves up and down along the axis; a number of spiral grooves are machined on the cylindrical surface of the valve core, and the cross-sectional shape of the spiral grooves is triangular, rectangular or trapezoidal.

3. The intermediate-temperature supercritical carbon dioxide antifreeze and anti-clogging safety valve according to claim 1, characterized in that, An annular flow storage groove is machined on the inner surface of the valve body. The annular flow storage groove has several tangential through holes evenly distributed inside. The direction of the tangential through holes is consistent with the direction of the spiral groove on the valve core surface.

4. The intermediate-temperature supercritical carbon dioxide antifreeze and anti-clogging safety valve according to claim 1, characterized in that, After the valve core is assembled with the valve seat and the inner valve body, a limiting step is machined into the inner hole of the inner valve body 2-3mm away from the upper end face of the valve core cylinder to limit the lift of the valve core.

5. The intermediate-temperature supercritical carbon dioxide antifreeze and anti-clogging safety valve according to claim 1, characterized in that, At least three annular guide plates are installed on the inner wall of the outer valve body. Each annular guide plate consists of 3-4 fan-shaped ring plates. Starting from the bottom of the outer valve body, the inner diameter of the first and third annular guide plates is in contact with the outer circular wall of the inner valve body, and a certain gap is maintained between the outer diameter and the inner wall of the outer valve body. The outer diameter of the second annular guide plate is in contact with the inner wall of the outer valve body, and a certain gap is maintained between the inner diameter and the outer circular wall of the inner valve body.

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