Temperature and pressure reduction device for supercritical liquid and temperature and pressure reduction method thereof

Abstract

The present invention relates to a supercritical liquid temperature reduction and pressure reduction device and a supercritical liquid temperature reduction and pressure reduction method. The supercritical liquid temperature reduction and pressure reduction device is composed of a first-stage temperature reduction and high-pressure device formed by a venturi tube mixer, a second-stage temperature reduction and medium-pressure device connected and connected to each other through a first connecting member and formed by an expansion temperature reduction and pressure reduction tank, and a third-stage temperature reduction and pressure reduction device connected and connected to each other through a second connecting member and formed by a water immersion tank; the first-stage temperature reduction and high-pressure device reduces the supercritical fluid from high temperature and high pressure to medium temperature and medium pressure through a first-stage temperature reduction and pressure reduction device, then reduces the supercritical fluid to low temperature and low pressure through a second-stage temperature reduction and pressure reduction device, and then reduces the pressure through a third-stage temperature reduction device, thereby reducing the temperature and pressure of the supercritical fluid.

Description

Technical Field

[0001] The present invention belongs to the technical field of temperature reduction and pressure reduction of high-temperature and high-pressure fluids, and in particular relates to a temperature reduction and pressure reduction device for supercritical liquids and a temperature reduction and pressure reduction method thereof. Background Art

[0002] The so-called supercritical refers to a special state of fluid matter. When the temperature and pressure of a fluid in vapor-liquid equilibrium are increased, thermal expansion causes the liquid density to decrease, and the increase in pressure causes the interface between the vapor and liquid phases to disappear, becoming a homogeneous system, which is the critical point. When the temperature and pressure of the fluid are higher than the critical temperature and critical pressure respectively, it is called a supercritical state. Supercritical fluids have good fluidity similar to that of gases, but their density is much greater than that of gases, so they have many unique physical and chemical properties.

[0003] Taking water as an example of supercritical working conditions, the critical point of water is 374.3℃ and 22.064MPa. Supercritical fluid working conditions are usually high-temperature and high-pressure fluid working conditions. It has always been a difficult problem to reduce the temperature and pressure of high-temperature and high-pressure fluids in the process. The valve core of the traditional pressure reducing valve is easily damaged, the seal is not tight, and it is easy to generate noise and cavitation, which poses a great safety risk. The high-temperature and high-pressure heat exchanger used for heat exchange and cooling has problems such as high investment. Summary of the invention

[0004] The purpose of the present invention is to provide a method for directly and fully mixing high and low temperature fluids for heat exchange and cooling, expanding and reducing pressure by using a venturi tube mixer, and realizing first-stage cooling and pressure reduction; then, reducing pressure by using an expander and pressure reducer and a spray cooler for cooling to achieve second-stage cooling and pressure reduction; and finally, reducing pressure and muffler by using small hole pressure reduction and water immersion heat exchange to achieve third-stage cooling and pressure reduction, and the method is used for cooling and pressure reduction of supercritical fluids.

[0005] The technical solution of the present invention is a supercritical liquid cooling and decompression device, which is special in that the cooling and decompression device is composed of a first-stage cooling and high-pressure device composed of a venturi tube mixer, a second-stage cooling and medium-pressure device interconnected and connected via a first connecting member and composed of an expanded cooling and decompression tank, and a third-stage cooling and decompression device interconnected and connected via a second connecting member and composed of a water immersion box; the first-stage cooling and low-pressure device reduces the supercritical fluid from high temperature and high pressure to medium temperature and medium pressure through a first-stage cooling and decompression device, then to low temperature and low pressure through a second-stage cooling and decompression device, and then to decompression through a third-stage cooling and decompression device, thereby realizing the cooling and decompression of the supercritical fluid.

[0006] Preferably: the first-stage cooling low-pressure equipment Venturi tube mixer is composed of a third connecting member connected through a contraction neck section, a mixing cooling section, and a fourth connecting member connected through a diffusion acceleration section; the contraction neck section is composed of a high-speed jet of a central diffusion hole tube formed by a contraction pipe in a cavity, so as to form sufficient negative pressure of suction cooling water at the cooling water inlet of the next mixing cooling section for direct mixing and heat exchange; the mixing cooling section is composed of a throat between the contraction neck section and the diffusion acceleration section, and at least one cooling water interface that penetrates the throat at an inclined angle from the outside; the diffusion acceleration section is composed of a trumpet-shaped central diffusion hole tube.

[0007] Preferably: the contraction neck section can be contracted in one, two or more sections, so that sufficient negative pressure is formed at the cooling water inlet of the mixed cooling section to inhale cooling water and achieve an ideal mixed cooling effect; the diffusion acceleration section can be accelerated in one, two or more sections, so that the cold and hot fluids are fully mixed for heat exchange and cooling, and diffusion and pressure reduction are achieved; the connecting components can be flanged, threaded, clamped or welded; the central diffusion hole tube can be made into a cylindrical, annular or cross-branch shape, and circular holes or slots can be opened on it to achieve the purpose of uniform distribution and small hole throttling and pressure reduction.

[0008] Preferably, the expansion cooling and decompression tank of the two-stage cooling and low-pressure equipment is composed of a container formed by an outer shell, an inner chamber formed by the container and separated from the outer shell, a central diffusion hole tube penetrating the container along the axis, and a spray cooler arranged between the outer shell and the inner shell; one end of the outer shell is provided with a pipe opening for the central diffusion hole tube to enter from the outside to the inside, and the other end of the outer shell is provided with a reducing cone connected to the second connecting member; the small-hole silencer shell arranged on the tube wall of the inner shell is provided with small holes for uniformly distributing heat flow and silencer, and the small-hole silencer shell is manufactured into a cylindrical, conical or spherical shape.

[0009] Preferably, the spray cooler is composed of a cooling water inlet radially penetrating the outer shell, a cooler collecting pipe communicating with the cooling water inlet, and nozzles evenly arranged on the cooler collecting pipe and facing the inner shell; the spray cooler can be manufactured into a straight tube shape for horizontal containers, a circular ring shape for vertical containers, and a cross tree branch shape for vertical containers. Circular holes, slots, or high-efficiency nozzles are opened on the spray cooler. The spray cooler sprays the cooler evenly and fully mixes with the heat medium for heat exchange, so as to achieve a better uniform distribution effect.

[0010] Preferably, the water immersion tank of the three-stage temperature reduction and pressure reduction equipment is composed of an open immersion water tank, a diffusion hole tube that penetrates axially from the outside to the inside at one end of the open immersion water tank, circular holes and slots opened on the wall of the immersion diffusion hole tube, and a cooling water outlet pipeline and a cooling water inlet pipeline that are axially opened at the top and bottom of the diffusion hole tube at the other end of the open immersion water tank; the immersion diffusion hole tube can be manufactured into a straight cylinder, an annular ring, or a cross tree branch shape; the open immersion water tank is cylindrical or rectangular, and is an open atmospheric pressure storage tank; the three-stage temperature reduction and pressure reduction equipment evenly distributes and silences the secondary temperature reduction and pressure reduction fluid through the immersion diffusion hole tube, and mixes and exchanges heat with the cooling water in the water immersion tank to achieve three-stage temperature reduction and pressure reduction.

[0011] Another technical solution of the present invention is a method for reducing temperature and pressure of a supercritical liquid reducing temperature and pressure device, which is special in that it comprises the following steps:

[0012] (1) The supercritical fluid that needs to be cooled and decompressed is contracted through the contraction neck section of the Venturi tube mixer to form a high-speed jet, and sufficient negative pressure is formed at the cooling water inlet of the mixing cooling section to inhale the cooling water. After sufficient mixing and cooling, it is decompressed through the diffusion acceleration section to achieve first-level cooling and decompression;

[0013] (2) The medium-temperature and medium-pressure fluid of the first-stage cooling and pressure reduction enters the central diffusion hole tube for diffusion and uniform distribution, enters the inner shell for expansion and pressure reduction, flows out through the small holes on the inner shell and mixes with the cooling water sprayed by the nozzle for heat exchange to reduce the temperature, thus achieving the second-stage cooling and pressure reduction;

[0014] ⑶ The secondary temperature and pressure reduction fluid is evenly distributed and silenced through the immersed diffusion hole tube, and mixed with the cooling water in the immersed water tank for heat exchange to achieve three-stage temperature and pressure reduction.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] ⑴ The present invention reduces temperature and pressure for many times, and the supercritical fluid is reduced from high temperature and high pressure to medium temperature and medium pressure through the first stage of temperature reduction and pressure reduction, and then to low temperature and low pressure through the second stage of temperature reduction and pressure reduction, and then to the third stage of temperature reduction and pressure reduction, so as to achieve the process purpose of reducing temperature and pressure of supercritical fluid. The high-risk part (high temperature and high pressure) of the temperature reduction and pressure reduction device accounts for a small proportion, the structure is simple and compact, the floor space is small, the installation and operation are convenient, the design and use flexibility are large, and the temperature reduction and pressure reduction effect is remarkable.

[0017] (2) The high-temperature and high-pressure supercritical fluid of the present invention adopts a Venturi tube for mixing to reduce temperature in the first stage, expands the volume and reduces pressure, and then sprays, mixes, heats and exchanges for reducing temperature and pressure in the second stage, is discharged through a small hole for silencer, and enters an open immersion water tank for reducing temperature and pressure in the third stage. The graded cooling and pressure reduction runs smoothly, safely and reliably.

[0018] ⑶ The present invention uses the contraction of the contraction neck section of the Venturi tube mixer (resistance pressure reduction) to form a high-speed jet, so that sufficient negative pressure is formed at the cooling water inlet of the mixing cooling section (throat) to inhale cooling water for direct mixing and heat exchange (temperature reduction), thereby achieving an ideal temperature reduction and pressure reduction effect.

[0019] (4) The high-temperature and high-pressure supercritical fluid of the present invention adopts a Venturi tube mixer, which forms a high-speed jet through the contraction of the contraction neck section (resistance pressure reduction), fully mixes and cools in the mixing and cooling section (throat), and pressure is reduced in the diffusion acceleration section. The structure is coherent and compact, which greatly reduces the proportion of high-temperature and high-pressure containers, and is conducive to the safe and reliable operation of the device.

[0020] ⑸ The present invention solves the problems that the valve core is easily damaged when a traditional pressure reducing valve is used to reduce the pressure of high-temperature and high-pressure fluids; the pressure difference before and after the valve is large, the seal is not tight, and noise and cavitation are easily generated; multi-stage pressure reduction is required for high pressure, the structure is complex, the reliability is poor, and there are safety issues.

[0021] (6) The present invention adopts an expansion cooling and pressure reduction tank, and the medium-temperature and medium-pressure fluid of the first-stage cooling and pressure reduction enters the central diffusion hole tube for diffusion and uniform distribution, enters the inner shell for expansion and pressure reduction, and flows out through the small holes on the inner shell to mix with the cooling water sprayed by the nozzle for heat exchange for cooling, thereby quickly achieving the effects of secondary cooling and pressure reduction, small hole silencing, etc.

[0022] ⑺The present invention adopts an open submerged water tank, and immerses all the submerged diffusion hole tubes in water for heat exchange and temperature reduction. The cooling is reliable. The open submerged water tank (without a tank cover) is used, and the operation is at normal pressure, which is safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is an assembly diagram of a supercritical liquid temperature and pressure reduction device of the present invention;

[0024] Figure 2 It is a simplified structural diagram of the venturi mixer of the present invention;

[0025] Figure 3 This is a simplified structural diagram of the capacity expansion and temperature reduction and pressure reduction tank of the present invention;

[0026] Figure 4 It is a schematic diagram of the structure of the open submerged water tank of the present invention.

[0027] Main component symbols:

[0028] Venturi mixer 1 Expansion pressure reduction and temperature reduction tank 2 Spray cooler 3 Small hole silencer shell 4 Water immersion box 5 High pressure flange 6 Contraction neck section 7 Cooling water interface 8 Mixing cooling section (throat) 9 Diffusion acceleration stage 10 First medium pressure flange 11 Second medium pressure flange 12 Outer shell 13 Inner housing 14 Central diffusion hole tube 15 Nozzle 16 Cooler header 17 Cooling water inlet 18 Variable diameter cone 19 First low pressure flange 20 Second low pressure flange 21 Open immersion tank 22 Immersed diffusion hole tube 23 Cooling water outlet pipeline 24 Cooling water inlet pipeline 25 DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings:

[0030] See also Figure 1As shown, the supercritical liquid temperature reduction and pressure reduction device is composed of a first-stage temperature reduction and high-pressure device formed by a venturi tube mixer 1, a second-stage temperature reduction and medium-pressure device interconnected and connected via a first medium-pressure flange 11 and composed of an expanded temperature reduction and pressure reduction tank 2, and a third-stage temperature reduction and pressure reduction device interconnected and connected via a first low-pressure flange 20 and composed of a water immersion box 5; the first-stage temperature reduction and low-pressure device reduces the supercritical fluid from high temperature and high pressure to medium temperature and medium pressure through a first-stage temperature reduction and pressure reduction device, then reduces it to low temperature and low pressure through a second-stage temperature reduction and pressure reduction device, and then reduces it through a third-stage temperature reduction device, thereby achieving the temperature reduction and pressure reduction of the supercritical fluid.

[0031] See also Figure 2 As shown, the first-stage cooling low-pressure equipment Venturi tube mixer 1 is composed of a contraction neck section 7 connected through a high-pressure flange 6, a mixing cooling section 9, and a first medium-pressure flange 11 connected through a diffusion acceleration section 10; the contraction neck section 7 is a high-speed jet formed by a contraction pipe in the cavity to form a central diffusion hole tube 15, which forms sufficient suction cooling water negative pressure for direct mixing and heat exchange at the cooling water inlet 8 of the next mixing cooling section 9; the mixing cooling section 9 is composed of a throat between the contraction neck section 9 and the diffusion acceleration section 10, and at least one cooling water interface 8 that penetrates the throat at an inclined angle from the outside; the diffusion acceleration section 10 is composed of a trumpet-shaped central diffusion hole tube 15.

[0032] In this embodiment, the contraction neck section 7 can be contracted in one, two or more sections, so that sufficient negative pressure is formed at the cooling water inlet 8 of the mixing cooling section 9 to inhale cooling water, thereby achieving an ideal mixing cooling effect; the diffusion acceleration section 10 can be accelerated in one, two or more sections, so that the cold and hot fluids are fully mixed for heat exchange and cooling, and diffusion and pressure reduction are achieved; the connecting components can be connected by flange, threaded, clamping ring or welding; the central diffusion hole tube 15 can be made into a cylindrical, annular or cross-branch shape, and circular holes or slots can be opened on it to achieve the purpose of uniform distribution and small hole throttling and pressure reduction.

[0033] See also Figure 3 As shown, the expansion cooling and decompression tank 2 of the two-stage cooling and low-pressure equipment is composed of a container formed by an outer shell 13, an inner shell 14 formed in the container and separated from the outer shell 1, a central diffusion hole tube 15 penetrating the container along the axis, and a spray cooler 3 arranged between the outer shell 13 and the inner shell 14; one end of the outer shell 1 is provided with a pipe opening for the central diffusion hole tube 15 to enter from the outside to the inside, and the other end of the outer shell 13 is provided with a reducing cone 19 connected to the first low-pressure flange 20; the small hole silencer shell 4 arranged on the tube wall of the inner shell 14 is provided with small holes for uniformly distributing heat flow and silencing, and the small hole silencer shell 4 is manufactured into a cylindrical, conical or spherical shape.

[0034] The spray cooler 3 is composed of a cooling water inlet 8 radially penetrating the outer shell 13, a cooler collecting pipe 17 communicating with the cooling water inlet 8, and nozzles 16 evenly arranged on the cooler collecting pipe 17 and facing the inner shell 14; the spray cooler 3 can be manufactured into a straight tube shape for horizontal containers, a ring shape for vertical containers, and a cross tree branch shape for vertical containers. Circular holes, slots, or high-efficiency nozzles are opened on the spray cooler. The spray cooler 3 evenly distributes the spray on the cooler and fully mixes with the heat medium for heat exchange, so as to achieve a better uniform distribution effect.

[0035] See also Figure 4 As shown, the water immersion tank 5 of the three-stage temperature reduction and pressure reduction equipment is composed of an open immersion water tank 22, a diffusion hole tube that penetrates axially from the outside to the inside at one end of the open immersion water tank 22, a circular hole and a slot hole opened on the immersion diffusion hole tube 23, and a cooling water outlet pipeline 24 and a cooling water inlet pipeline 25 that are axially opened at the top and bottom of the diffusion hole tube at the other end of the open immersion water tank 22; the immersion diffusion hole tube 23 can be manufactured into a straight cylinder, an annular ring, or a cross tree branch shape, and the open immersion water tank 22 is cylindrical or rectangular, forming an open atmospheric pressure storage tank; the three-stage temperature reduction and pressure reduction equipment evenly distributes and silences the secondary temperature reduction and pressure reduction fluid through the immersion diffusion hole tube 23, and mixes and exchanges heat with the cooling water in the open immersion water tank 22 to achieve three-stage temperature reduction and pressure reduction.

[0036] See also Figure 1 to Figure 4 As shown, the method for reducing temperature and pressure in a supercritical liquid reducing temperature and pressure device comprises the following steps:

[0037] (1) The supercritical fluid that needs to be cooled and decompressed is contracted by the contraction neck section 7 of the Venturi tube mixer 1 to form a high-speed jet, and sufficient negative pressure is formed at the cooling water interface 8 of the mixing cooling section 9 to inhale cooling water. After sufficient mixing and cooling, it is decompressed by the diffusion acceleration section 10 to achieve first-level cooling and decompression;

[0038] (2) The medium-temperature and medium-pressure fluid of the first-stage cooling and pressure reduction enters the central diffusion hole tube 15 for diffusion and uniform distribution, enters the inner shell 14 for expansion and pressure reduction, flows out through the small holes on the inner shell 14 and mixes with the cooling water sprayed by the nozzle 16 for heat exchange to reduce the temperature, thereby achieving the second-stage cooling and pressure reduction;

[0039] (3) The secondary temperature and pressure reduction fluid is evenly distributed and silenced through the immersed diffusion hole tube 23, and mixed with the cooling water in the open immersed water tank 22 for heat exchange, so as to achieve the third stage temperature and pressure reduction.

[0040] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A supercritical liquid temperature and pressure reduction device, characterized in that: The temperature reduction and pressure reduction device is composed of a first-stage temperature reduction and high-pressure equipment composed of a venturi tube mixer, a second-stage temperature reduction and medium-pressure equipment which is interconnected and connected via a first connecting member and is composed of an expanded temperature reduction and pressure reduction tank, and a third-stage temperature reduction and pressure reduction equipment which is interconnected and connected via a second connecting member and is composed of a water immersion box; the first-stage temperature reduction and high-pressure equipment reduces the supercritical fluid from high temperature and high pressure to medium temperature and medium pressure through a first-stage temperature reduction and pressure reduction device, then reduces it to low temperature and low pressure through a second-stage temperature reduction and pressure reduction device, and then reduces it through a third-stage temperature reduction device, thereby achieving the purpose of the supercritical fluid temperature reduction and pressure reduction process.

2. The supercritical liquid temperature and pressure reduction device according to claim 1, characterized in that: The Venturi tube mixer of the first-stage cooling and low-pressure equipment is composed of a contraction neck section connected and penetrated by a third connecting member, a mixing cooling section, and a fourth connecting member connected and penetrated by a diffusion acceleration section; the contraction neck section is composed of a high-speed jet of a central diffusion hole tube formed after the contraction pipe in the cavity, which forms a negative pressure sufficient to inhale cooling water at the cooling water inlet of the mixing cooling section for direct mixing and heat exchange; the mixing cooling section is composed of a throat between the contraction neck section and the diffusion acceleration section, and at least one cooling water interface that penetrates the throat at an inclined angle from the outside; the diffusion acceleration section is composed of a trumpet-shaped central diffusion hole tube.

3. The temperature and pressure reduction device for supercritical liquid according to claim 2, characterized in that: The contraction neck section can be contracted in one, two or more sections so that sufficient negative pressure is formed at the cooling water inlet of the mixed cooling section to inhale cooling water and achieve an ideal mixed cooling effect; the diffusion acceleration section can be accelerated in one, two or more sections so that the cold and hot fluids are fully mixed for heat exchange and temperature reduction, and diffusion and pressure reduction are achieved; the connecting components can be flanged, threaded, clamped or welded; the central diffusion hole tube can be made into a cylindrical, annular or cross-branch shape, and circular holes or slots can be opened on it to achieve the purpose of uniform distribution and small hole throttling and pressure reduction.

4. The temperature and pressure reduction device for supercritical liquid according to claim 1, characterized in that: The expansion cooling and decompression tank of the two-stage cooling and low-pressure equipment is composed of a container formed by an outer shell, an inner chamber formed by the container and separated from the outer shell, a central diffusion hole tube penetrating the container along the axis, and a spray cooler arranged between the outer shell and the inner shell; one end of the outer shell is provided with a pipe opening for the central diffusion hole tube to enter from the outside to the inside, and the other end of the outer shell is provided with a reducing cone connected to the second connecting member; the small-hole silencer shell arranged on the tube wall of the inner shell is provided with small holes for uniformly distributing heat flow and silencer, and the small-hole silencer shell is manufactured into a cylindrical, conical or spherical shape.

5. The temperature and pressure reduction device for supercritical liquid according to claim 4, characterized in that: The spray cooler is composed of a cooling water inlet radially penetrating the outer shell, a cooler collecting pipe communicating with the cooling water inlet, and nozzles evenly arranged on the cooler collecting pipe and facing the inner shell; the spray cooler can be manufactured into a straight tube shape for horizontal containers, a circular ring shape for vertical containers, and a cross tree branch shape for vertical containers. Circular holes, slots, or high-efficiency nozzles are opened on the spray cooler. The spray cooler sprays the cooler evenly and fully mixes with the heat medium for heat exchange, so as to achieve a better uniform distribution effect.

6. The temperature and pressure reduction device for supercritical liquid according to claim 1, characterized in that: The water immersion tank of the three-stage temperature reduction and pressure reduction equipment is composed of an open immersion water tank, an immersion diffusion hole tube that penetrates axially from the outside to the inside at one end of the open immersion water tank, circular holes and slot holes opened on the wall of the immersion diffusion hole tube, and a cooling water outlet pipeline and a cooling water inlet pipeline that are axially opened at the top and bottom of the diffusion hole tube at the other end of the open immersion water tank; the immersion diffusion hole tube can be manufactured into a straight cylinder, an annular ring, or a cross tree branch shape; the open immersion water tank is cylindrical or rectangular, and is an open atmospheric pressure storage tank; the three-stage temperature reduction and pressure reduction equipment evenly distributes and silences the secondary temperature reduction and pressure reduction fluid through the immersion diffusion hole tube, and mixes and exchanges heat with the cooling water in the water immersion tank to achieve three-stage temperature reduction and pressure reduction.

7. A method for cooling and decompressing a supercritical liquid cooling and decompressing device according to claim 1, characterized in that: Including the following steps: (1) The supercritical fluid that needs to be cooled and decompressed is contracted through the contraction neck section of the Venturi tube mixer to form a high-speed jet, and sufficient negative pressure is formed outside the cooling water inlet of the mixing cooling section to inhale cooling water. After sufficient mixing and cooling, it is decompressed through the diffusion acceleration section to achieve first-level cooling and decompression; (2) The medium-temperature and medium-pressure fluid of the first-stage cooling and pressure reduction enters the central diffusion hole tube for diffusion and uniform distribution, enters the inner shell for expansion and pressure reduction, flows out through the small holes on the inner shell and mixes with the cooling water sprayed by the nozzle for heat exchange to reduce the temperature, thus achieving the second-stage cooling and pressure reduction; ⑶ The secondary temperature and pressure reduction fluid is evenly distributed and silenced through the immersed diffusion hole tube, and mixed with the cooling water in the immersed water tank for heat exchange to achieve three-stage temperature and pressure reduction.

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