Novel LNG vaporizer assembly

Abstract

The invention relates to a novel LNG vaporizer assembly which comprises a composition analyzer, a refrigerant buffer tank and an LNG vaporizer set. The LNG vaporizer group is connected with an LNG feeding pipeline; an LNG feeding valve is arranged on the LNG feeding pipeline; a sampling point of the composition analyzer is positioned at the front end of the LNG feeding valve; a liquid-phase refrigerant outlet of the LNG vaporizer group is connected with the refrigerant user group; the refrigerant user group is connected with the refrigerant buffer tank, and the refrigerant buffer tank is connected with a gas-phase refrigerant inlet of the LNG vaporizer group. The LNG vaporizer assembly is simple in structure, small in investment, suitable for LNG raw materials of various components and safe and stable in operation. A special working medium propylene or ethylene is selected as a working medium for recycling LNG cold energy, a large amount of high-grade and multi-grade cooling capacity can be provided for other devices after a large amount of LNG cold energy is recycled, the energy consumption of the device is greatly reduced, and recycling of resources is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of petrochemical industry, and in particular relates to a novel LNG vaporizer assembly for a special working fluid, and specifically relates to a novel LNG vaporizer assembly, which realizes the recovery and utilization of cold energy of LNG while realizing the vaporization of LNG. Background Art

[0002] LNG vaporizer is a heat exchanger specially used for liquefied natural gas gasification. It is mainly used in large coastal LNG receiving stations, LNG liquefaction plants, LNG gasification stations, LNG filling stations, etc. It is a key equipment to realize the gasification function. According to the properties and components of LNG, LNG vaporizers need to have different structural designs. Common LNG vaporizers mainly include open rack vaporizers (ORV), submerged combustion vaporizers (SCV), intermediate fluid vaporizers (IFV), air temperature vaporizers, forced ventilation vaporizers, hot air heating vaporizers, vacuum steam vaporizers (VSV), intermediate medium air temperature vaporizers, hot water bath vaporizers, etc. The structures of these vaporizers are relatively complex. Some are aluminum alloy heat transfer tubes, and the heat transfer tubes have star-shaped sections and spiral rods inside and fins outside. Some are spirally wound heat exchangers, so the manufacturing structure is complex and the equipment cost is high. In addition, none of these vaporizers can be applied to all LNG raw materials. High-efficiency vaporizers.

[0003] On the other hand, LNG vaporizers are classified according to the different heat media for LNG vaporization. Common heat media for LNG vaporization include air, river water or seawater, natural gas combustion, electric heating, factory waste heat, etc. These heat media are only used to vaporize LNG, but the cold energy of LNG is not recycled and reused, and all this cold energy is wasted. When low-temperature LNG is vaporized, a large amount of cold energy is released, about 850KJ / Kg. This part of cold energy should be fully recycled to achieve the purpose of saving energy and improving economic benefits.

[0004] In traditional petroleum and chemical plants, ethylene compressors are often used when olefin separation units are involved. The cold energy provided by the propylene compressor is used to pre-cool the raw materials of the separation system or to condense the materials at the top of the tower. Generally, propylene circulating refrigeration compressors can provide refrigerants at four temperatures of 5°C, -8°C, -25°C, and -40°C for different systems. Depending on the composition of the separated substances, some devices may also require ethylene refrigeration compressors at lower temperatures to provide separation energy for the device. The compressor system is the key equipment for the stable operation of the olefin separation unit. It is also the core equipment in the entire unit with a relatively large investment, a long production cycle, and high safety level requirements. It is the top priority in the entire process design; but its equipment is complex and the investment cost is high.

[0005] Therefore, it is of great significance to develop a new LNG vaporizer assembly with strong adaptability to LNG raw materials and low equipment investment cost. Summary of the invention

[0006] In view of this, the present invention aims to propose a novel LNG vaporizer assembly, which adopts a special working fluid, such as ethylene or propylene, to solve at least one problem in the above-mentioned background technology.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] A new type of LNG vaporizer assembly, including a composition analyzer, a refrigerant buffer tank, and an LNG vaporizer group;

[0009] The LNG vaporizer group is connected to an LNG feed pipeline; an LNG feed valve is provided on the LNG feed pipeline; the sampling point of the composition analyzer is located at the front end of the LNG feed valve;

[0010] The liquid-phase refrigerant outlet of the LNG vaporizer group is connected to the refrigerant user group; the refrigerant user group is connected to the refrigerant buffer tank, and the refrigerant buffer tank is connected to the gas-phase refrigerant inlet of the LNG vaporizer group.

[0011] Preferably, the LNG vaporizer group includes a heavy LNG vaporizer and a light LNG vaporizer;

[0012] The heavy LNG inlet of the heavy LNG vaporizer and the light LNG inlet of the light LNG vaporizer are connected with an LNG feed pipeline;

[0013] The LNG feed valve is respectively connected to the heavy LNG inlet of the heavy LNG vaporizer or the light LNG inlet of the light LNG vaporizer;

[0014] The first liquid-phase refrigerant outlet located at the light LNG vaporizer and the second liquid-phase refrigerant outlet located at the heavy LNG vaporizer are respectively connected to the refrigerant user groups;

[0015] The refrigerant buffer tank is respectively connected to a first gas-phase refrigerant inlet located on the light LNG vaporizer and a second gas-phase refrigerant inlet located on the heavy LNG vaporizer.

[0016] The LNG vaporizer assembly of the present invention has a simple structure and low investment. The LNG vaporizer assembly can be applied to LNG raw materials of various components and has safe and stable operation. Special working fluids such as propylene or ethylene are selected as working fluids for recovering LNG cold energy. After recovering a large amount of LNG cold energy, a large amount of high-grade and multi-grade cold energy can be provided for other devices, which greatly reduces the energy consumption of the device and realizes the recycling of resources.

[0017] Preferably, the LNG vaporizer assembly further comprises an LNG separation tank;

[0018] The liquid phase outlet of the LNG separation tank is connected to the LNG feed pipeline; the liquid phase outlet of the LNG separation tank is provided with an LNG pump;

[0019] The top of the LNG separation tank is provided with an LNG gas delivery pipe;

[0020] The LNG separation tank is connected to the light LNG outlet of the light LNG vaporizer and the heavy LNG outlet of the heavy LNG vaporizer respectively.

[0021] Preferably, the LNG vaporizer assembly further comprises a refrigerant storage tank, which is respectively connected to a first liquid-phase refrigerant outlet located at the light LNG vaporizer, a second liquid-phase refrigerant outlet located at the heavy LNG vaporizer, and a refrigerant user group.

[0022] Preferably, the detection signal of the composition analyzer is used to control the opening and closing state of the LNG feed valve.

[0023] Furthermore, a refrigerant pump is provided between the refrigerant storage tank and the refrigerant user group; a start-up refrigerant inlet is provided on the refrigerant storage tank for connecting the start-up refrigerant pipeline;

[0024] The refrigerant pump is connected to the refrigerant user group through a circulating liquid-phase refrigerant pipe, and the refrigerant user group is connected to the refrigerant buffer tank through a circulating gas-phase refrigerant pipe;

[0025] And / or, it also includes a start-up vaporizer, one end of the start-up vaporizer is connected to the refrigerant pump, and the other end of the start-up vaporizer is connected to the refrigerant buffer tank;

[0026] The refrigerant user group is connected in parallel with the start-up vaporizer;

[0027] And / or, the refrigerant buffer tank is connected to the light LNG vaporizer and the heavy LNG vaporizer respectively through a refrigerant valve;

[0028] And / or, the detection signal of the component analyzer is used to control the opening and closing state of the refrigerant valve.

[0029] And / or, when the composition analyzer detects that the C1 content of the LNG feedstock is greater than 95%, the LNG feed valve is connected to the light LNG inlet connected to the shell side of the light LNG vaporizer, and at the same time, the refrigerant valve is connected to the first gas phase refrigerant inlet connected to the tube side of the light LNG vaporizer;

[0030] When the composition analyzer detects that the C1 content of the LNG raw material is less than or equal to 95%, the LNG feed valve is connected to the heavy LNG inlet connected to the heavy LNG vaporizer tube side, and at the same time, the refrigerant valve is connected to the second gas phase refrigerant inlet connected to the heavy LNG vaporizer shell side;

[0031] And / or, if the processing amount of LNG raw material increases, the light LNG vaporizer and the heavy LNG vaporizer are operated simultaneously.

[0032] Furthermore, the light LNG vaporizer includes a light LNG shell and a light LNG tube bundle. A plurality of U-shaped heat exchange tube bundles are arranged in the light LNG shell. The heat exchange tubes are transversely arranged in the light LNG shell. A light LNG outlet connected to the shell side of the light LNG vaporizer is provided on the top of the light LNG shell. The LNG raw material exchanges heat with the gas-phase refrigerant located in the tube side in the shell side of the light LNG vaporizer.

[0033] Furthermore, a first gas-phase refrigerant inlet is provided at the upper portion of the pipe box of the light LNG vaporizer, and a first liquid-phase refrigerant outlet is provided at the lower portion of the pipe box of the light LNG vaporizer, and the first gas-phase refrigerant inlet is connected to the first liquid-phase refrigerant outlet through the pipe box, the tube sheet and the U-shaped heat exchange tube bundle;

[0034] The light LNG shell of the light LNG vaporizer includes a first-stage shell, a transition-stage shell and a second-stage shell, wherein the first-stage shell and the second-stage shell are connected via the transition-stage shell; the diameter of the first-stage shell is smaller than the diameter of the second-stage shell; the lowermost end of the first-stage shell is flush with the lowermost end of the second-stage shell;

[0035] The inlet end of the U-shaped heat exchange tube is located on one side of the first shell; the U-shaped end of the U-shaped heat exchange tube is located in the second shell;

[0036] A plurality of staggered single-bow baffles and a first support plate are arranged between the light LNG tube bundle and the light LNG shell. In addition, an overflow weir is also arranged in the light LNG shell, and the overflow weir is arranged on the side close to the outer end of the U-bend.

[0037] Furthermore, a light LNG inlet is provided at the bottom of the light LNG shell of the light LNG vaporizer, a light LNG outlet is provided at the top of the light LNG shell, and a light LNG heavy component liquid phase outlet is also provided at the bottom of the light LNG shell; the light LNG inlet is arranged on a side close to the gas phase refrigerant inlet and outlet, and the light LNG gas phase outlet is arranged on a side away from the refrigerant inlet and outlet;

[0038] The light LNG inlet is located on a side of the overflow weir close to the pipe box, and the light LNG heavy component liquid phase outlet is located on a side of the overflow weir away from the pipe box;

[0039] The light LNG outlet is located at the top of the second-stage shell; the first gas-phase refrigerant inlet of the light LNG vaporizer is connected to the refrigerant buffer tank, the first liquid-phase refrigerant outlet of the light LNG vaporizer is connected to the refrigerant storage tank, the refrigerant storage tank is connected to the refrigerant pump, and after the refrigerant pump sends the liquid-phase refrigerant to the user of the petrochemical separation device for use, the gas-phase refrigerant returns to the refrigerant buffer tank for recycling again.

[0040] Further, the heavy LNG vaporizer includes a heavy LNG shell and a heavy LNG tube bundle;

[0041] A plurality of U-shaped heat exchange tube bundles are arranged in the heavy LNG shell, and the U-shaped heat exchange tubes are arranged transversely in the heavy LNG shell;

[0042] The gas phase refrigerant exchanges heat with the LNG raw material located in the tube side of the heavy LNG vaporizer in the shell side of the heavy LNG shell.

[0043] Furthermore, a heavy LNG inlet is provided at the bottom of the pipe box of the heavy LNG vaporizer, a heavy LNG outlet is provided at the top of the pipe box of the heavy LNG vaporizer, and the heavy LNG inlet and the heavy LNG outlet are connected through the pipe box, the tube sheet and the U-shaped heat exchange tube bundle;

[0044] An outer guide ring is provided on the shell side inlet of the heavy LNG vaporizer, and 2 to 3 air inlet grooves are evenly opened on the outer guide ring. The gas phase refrigerant is connected with the cavity between the shell side of the heavy LNG vaporizer through the air inlet grooves.

[0045] Further, a second liquid-phase refrigerant outlet is provided at the bottom of the shell of the heavy LNG vaporizer;

[0046] A plurality of single-bow or double-bow baffles are arranged in the heavy LNG shell of the heavy LNG vaporizer, and a plurality of through holes are arranged on the baffles to support the U-shaped heat exchange tube bundle;

[0047] The second gas-phase refrigerant inlet of the heavy LNG vaporizer is connected to the refrigerant buffer tank, and the second liquid-phase refrigerant outlet of the heavy LNG vaporizer is connected to the refrigerant storage tank.

[0048] After adopting the novel LNG vaporizer assembly of the present invention and using special working fluids such as ethylene or propylene as refrigerant, the power consumption during the operation of the device is significantly reduced, while the amount of circulating water is saved and the equipment investment cost is reduced;

[0049] By using the above device of the present invention, it can be concluded through design optimization calculation of the light hydrocarbon recovery device that the power consumption is reduced by 1598KWh and the circulating water consumption is saved by 905t / h. According to preliminary calculation, compared with the traditional refrigeration using propylene compressor, the equipment cost can be reduced by more than 20%.

[0050] Compared with the prior art, the novel LNG vaporizer assembly described in the present invention has the following advantages:

[0051] The process is simple, energy consumption is low, investment is low, and operation is stable. According to the optimization design results of the light hydrocarbon recovery device, after adopting the new LNG vaporizer assembly of the present invention, the power consumption of the device during operation is significantly reduced, while the amount of circulating water is saved and the equipment investment cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0053] Figure 1 This is an overall schematic diagram of a novel LNG vaporizer assembly according to Example 1 of the present invention;

[0054] Figure 2 This is a schematic diagram of the light LNG vaporizer described in Example 3 of the present invention;

[0055] Figure 3 This is a schematic diagram of a heavy LNG vaporizer according to Example 4 of the present invention;

[0056] Figure 4 This is a schematic diagram of the heavy LNG tube bundle described in Example 4 of the present invention.

[0057] Description of reference numerals:

[0058] 1. LNG separation tank; 2. LNG pump; 3. Composition analyzer; 4. LNG feed valve; 5. Heavy LNG vaporizer; 6. Light LNG vaporizer; 7. Refrigerant valve; 8. Refrigerant storage tank; 9. Refrigerant pump; 10. Refrigerant buffer tank; 11. Start-up vaporizer; 12. Refrigerant user group; 13. LNG raw material self-tank area; 14. LNG gas delivery pipe; 15. Start-up refrigerant pipeline; 16. Circulating liquid phase refrigerant pipe; 17. Circulating gas phase refrigerant pipe; 19. Light LNG tube bundle; 20. Light LNG shell; 21. A gas-phase refrigerant inlet; 22. A first liquid-phase refrigerant outlet; 23. A transition section shell; 24. A single-bow baffle; 25. A first support plate; 26. A light LNG inlet; 27. A light LNG outlet; 28. An overflow weir; 29. ​​A heavy component liquid-phase outlet; 30. A heavy LNG tube bundle; 31. A heavy LNG shell; 32. A heavy LNG inlet; 33. A heavy LNG outlet; 34. An outer guide collar; 35. An inlet groove; 36. A second gas-phase refrigerant inlet; 37. A second liquid-phase refrigerant outlet; 38. A baffle of a heavy LNG vaporizer. DETAILED DESCRIPTION

[0059] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0060] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0061] Example 1

[0062] like Figure 1 This embodiment provides a novel LNG vaporizer assembly, including a composition analyzer 3, a refrigerant buffer tank 10, a heavy LNG vaporizer 5 and a light LNG vaporizer 6;

[0063] The heavy LNG inlet 32 ​​of the heavy LNG vaporizer 5 and the light LNG inlet 26 of the light LNG vaporizer 6 are connected with LNG feed pipelines;

[0064] The LNG feed pipeline is provided with LNG feed valves 4, and the LNG feed valves 4 are respectively connected to the heavy LNG inlet 32 ​​of the heavy LNG vaporizer 5 or the light LNG inlet 26 of the light LNG vaporizer 6;

[0065] The sampling point of the composition analyzer 3 is located at the front end of the LNG feed valve 4;

[0066] The first liquid-phase refrigerant outlet 22 located at the light LNG vaporizer 6 and the second liquid-phase refrigerant outlet 37 located at the heavy LNG vaporizer 5 are respectively connected to the refrigerant user group 12;

[0067] The refrigerant user group 12 is connected to the refrigerant buffer tank 10 , and the refrigerant buffer tank 10 is respectively connected to the first gas-phase refrigerant inlet 21 located on the light LNG vaporizer 6 and the second gas-phase refrigerant inlet 36 located on the heavy LNG vaporizer 5 .

[0068] The LNG raw materials from the boundary area are connected to the tube side of the heavy LNG vaporizer 55 or the shell side of the light LNG vaporizer 66 through the LNG feed pipeline; the composition analyzer 3 is located on the LNG feed pipeline to detect the composition of the LNG raw materials, and the detection signal is used to control the opening and closing state of the LNG feed valve 4 to feed the light LNG vaporizer 6 or the heavy LNG vaporizer 5 respectively; the LNG feed valve 4 can be a three-way valve. After the gas phase refrigerant exchanges heat with the LNG raw materials in the heavy LNG vaporizer 5 or the light LNG vaporizer 6, a liquid phase refrigerant is obtained, and the refrigerant uses special working fluids such as propylene or ethylene; after the liquid phase refrigerant provides cooling for the refrigerant user group 12, it enters the refrigerant buffer tank 10, and then re-enters the light LNG vaporizer 6 or the heavy LNG vaporizer 5.

[0069] Example 2

[0070] In this embodiment, based on the embodiment 1, the novel LNG vaporizer assembly further includes an LNG separation tank 1;

[0071] The liquid phase outlet of the LNG separation tank 1 is connected to the LNG feed pipeline; the liquid phase outlet of the LNG separation tank 1 is provided with an LNG pump 2;

[0072] The top of the LNG separation tank 1 is provided with an LNG gas delivery pipe 14;

[0073] The LNG separation tank 1 is connected to the light LNG outlet 27 of the light LNG vaporizer 6 and the heavy LNG outlet 33 of the heavy LNG vaporizer 5 respectively.

[0074] The LNG raw material is vaporized by the light LNG vaporizer or the heavy LNG vaporizer and then sent to the LNG separation tank 1. After being separated in the LNG separation tank 1, the gaseous LNG is sent out as a product, and the liquid LNG is pressurized by the LNG pump 2 and then merged into the LNG raw material main pipe for recycling. At the same time, the liquid start-up refrigerant from the boundary area, which is propylene or ethylene, is loaded into the refrigerant storage tank 8 at one time. During the start-up stage, it is sent to the start-up vaporizer 11 through the refrigerant pump 9. The vaporized refrigerant is sent to the shell side of the heavy LNG vaporizer 5 or the tube side of the light LNG vaporizer 6 through the refrigerant valve 7. The condensed liquid refrigerant flows back to the refrigerant storage tank 8. After the system establishes pressure balance, the start-up vaporizer 11 is cut off, and the refrigerant in the refrigerant storage tank 8 is sent to the nearby refrigerant user group 12 through the refrigerant pump 9, and is sent to the refrigerant buffer tank 10 after being vaporized in the refrigerant user group 12, and the above cycle is repeated to provide a continuous supply of cold energy for the refrigerant user group 12. The LNG feed valve 4 and the refrigerant valve 7 simultaneously receive signals from the composition analyzer 3, and the specific signals are: when the C1 content of the LNG raw material is less than or equal to 95%, the LNG feed valve 4 and the refrigerant valve 7 simultaneously open the valve channel leading to the light LNG vaporizer 6; when the C1 content of the LNG raw material is greater than 95%, the LNG feed valve 4 and the refrigerant valve 7 simultaneously open the valve channel leading to the heavy LNG vaporizer 5.

[0075] In specific use, the light LNG vaporizer 6 or the heavy LNG vaporizer 5 can be used separately according to actual conditions, or, when the LNG processing capacity is large and is used at peak, the three-way valves of the light LNG vaporizer 6 and the heavy LNG vaporizer 5 can be opened at the same time, that is, the LNG vaporizer components are activated at the same time to increase the processing capacity. When the content of C1 in the LNG raw material is less than or equal to 95%, the material composition is complex and the boiling range is wide, which is defined as heavy LNG. At this time, the material enters the heavy LNG vaporizer 5 through the three-way valve. When the content of C1 in the LNG raw material is greater than 95%, the material composition is simple and the boiling range is small, which is defined as light LNG. At this time, the material is switched into the light LNG vaporizer 6 through the three-way valve.

[0076] Example 3

[0077] This embodiment is based on embodiment 2. Figure 2 As shown;

[0078] The light LNG vaporizer 6 includes a light LNG tube bundle 19 and a light LNG shell 20. The light LNG tube bundle 19 is a U-shaped heat exchange tube. Several light LNG tube bundles 19 are transversely arranged in the light LNG shell 20. The gas-phase refrigerant exchanges heat with the light LNG raw material located in the shell side in the heat exchange tube bundle 19 of the light LNG vaporizer. A first gas-phase refrigerant inlet 21 is provided at the upper part of the tube box of the light LNG vaporizer, and a first liquid-phase refrigerant outlet 22 is provided at the lower part of the tube box of the light LNG vaporizer. The first gas-phase refrigerant inlet 21 is connected to the tube bundle of the light LNG vaporizer through the tube box and the tube sheet, and the first liquid-phase refrigerant outlet 22 is connected to the tube bundle of the light LNG vaporizer through the tube box and the tube sheet. A transition section shell 23 is provided in the middle part of the light LNG shell 20. Several staggered single-bow baffles 24 and a first support plate 25 are provided between the light LNG shell 20 and the light LNG tube bundle 19. An overflow weir 28 is provided in the light LNG shell 20, and the overflow weir 28 is arranged on the side away from the first liquid-phase refrigerant outlet. The single-bow baffle 24 is arranged on a side close to the refrigerant outlet and on a side of the transition section 23; a plurality of through holes are arranged on the single-bow baffle 24 and the first support plate 25; a light LNG inlet 26 is arranged at the bottom of the light LNG shell 20, and a light LNG outlet 27 is arranged at the upper part of the light LNG shell 20; the light LNG inlet 26 is arranged on a side close to the refrigerant outlet, the light LNG outlet 27 is arranged on a side away from the refrigerant outlet, and the heavy component liquid phase outlet 29 is arranged at the bottom of the light LNG shell 20; the light LNG outlet 27 is arranged on one side of the overflow weir 28, and the heavy component liquid phase outlet 29 is arranged on the other side of the overflow weir 28; the first gas-phase refrigerant inlet 21 of the light LNG vaporizer 6 is connected to the refrigerant buffer tank 10 through a pipeline of the refrigerant valve 7, the first liquid-phase refrigerant outlet 22 of the light LNG vaporizer 6 is connected to the refrigerant storage tank 8, and is sent to the refrigerant user group 12 through the refrigerant pump 9, and the gas-phase refrigerant after being vaporized in the refrigerant user group 12 is circulated to the refrigerant buffer tank 10, so that the cold energy of LNG is recycled in sequence.

[0079] Example 4

[0080] This embodiment is based on embodiment 2. Figure 3 , 4 As shown;

[0081] The heavy LNG vaporizer 5 includes a heavy LNG shell 30 and a heavy LNG tube bundle 31; a plurality of U-shaped heat exchange tubes are arranged in the heavy LNG shell 30, and a plurality of heat exchange tubes are arranged transversely in the heavy LNG vaporizer shell 30, and the heavy LNG tube bundle 31 is arranged in the heavy LNG vaporizer shell 30; the gas-phase refrigerant exchanges heat with the heavy LNG raw material located in the tube bundle in the shell side of the heavy LNG vaporizer. A heavy LNG inlet 32 ​​is provided at the lower part of the pipe box of the heavy LNG vaporizer 5, and a heavy LNG outlet 33 is provided at the upper part of the pipe box of the heavy LNG vaporizer 5. The heavy LNG inlet 32 ​​is connected with the heat exchange tube bundle through the pipe box and the tube sheet, and the heavy LNG outlet 33 is connected with the heat exchange tube bundle through the pipe box and the tube sheet; an outer guide ring 34 is provided on the heavy LNG shell 30; 2 to 3 inlet grooves 35 are evenly arranged on the outer guide ring 34 to facilitate a large amount of gas-phase refrigerant to evenly enter the second gas-phase refrigerant inlet 36 of the shell side of the heavy LNG vaporizer 5. The gas-phase refrigerant enters the heavy LNG shell 30 through the inlet groove 35, flows through the baffle 38 with a plurality of through holes, flows to the second liquid-phase refrigerant outlet 37 and is sent to the refrigerant storage tank 8, and is sent to the refrigerant user group 12 through the refrigerant pump 9. The gas-phase refrigerant vaporized in the refrigerant user group 12 is circulated and sent to the refrigerant buffer tank 10, so that the cold energy of LNG is recycled in sequence.

[0082] The LNG from the boundary area and the low-temperature special refrigerant undergo inter-wall heat exchange in the LNG vaporizer group. The propylene or ethylene condensed into liquid is pressurized by a low-temperature pump and divided into 2 or more levels according to the separation temperature requirements and properties of the refrigerant user group. Generally, it is divided into at least 2 levels, and the level above 5°C is one level. This level can switch the circulating water users in the original separation device to refrigerant users, which not only improves the heat exchange efficiency, but also greatly saves the consumption of circulating water. The other refrigerant classification can be divided into -8°C, -20°C, -40°C, -60°C and even -80°C refrigerant according to the actual needs of the device users. This not only realizes the graded utilization of energy levels, but also reduces the investment cost of ultra-low temperature equipment and improves the heat exchange efficiency of the equipment.

[0083] A project example in a certain place

[0084] When the refrigerant is ethylene, and the composition analyzer detects that the LNG raw material is heavy LNG as shown in Table 1, it is known through simulation that the supercooling load is large, accounting for 50.71% of the total heat load, so under this condition, it is necessary to fully consider the design of the supercooling section and the maximum recovery of cold capacity. In this application, in order to save investment and land, at this time, the heavy LNG raw material enters the heavy LNG vaporizer, and the specific schematic diagram of the heavy LNG vaporizer equipment design is as follows Figure 3 , 4As shown, the bundle length of the heavy LNG heat exchange tube is 7.5 meters, and the bundle diameter of the heavy LNG heat exchange tube is 1.8 meters (the bundle diameter includes the sum of the tube diameter and the tube center distance); the shell side is evenly arranged with single-bow baffles with an opening rate of about 30% to 40%. In addition, due to the large gas volume at the shell side inlet, in order to avoid the large opening of the shell side cylinder of the heavy LNG vaporizer resulting in a reduction in the number of pipes, and to prevent the vibration of the pipes caused by excessive gas flow rate, this design sets a special guide device at the shell side inlet of the heavy LNG vaporizer. The width of the outer guide ring 34 is 1.4 meters and the height is 0.5 meters. 2 to 3 grooves are symmetrically opened on the guide device to ensure the stable flow of the fluid and the reasonable structure of the heavy LNG vaporizer.

[0085] When the refrigerant is ethylene, and the composition analyzer detects that the LNG raw material is light LNG as shown in Table 1, the material composition is simple and easy to vaporize. At this time, the light LNG raw material enters the light LNG vaporizer. The specific schematic diagram of the light LNG vaporizer equipment design is as follows: Figure 2 As shown, the bundle length of the heat exchange tubes of the light LNG vaporizer is 7.5 meters, the bundle diameter of the light LNG vaporizer is 1.8 meters, and the shell diameter is 2.4 meters; 3 single-bow baffles with an opening rate of 30% to 40% are evenly arranged in the supercooling section of the shell of the light LNG vaporizer, and then enter the vaporization section with a shell flow length of 5.5 meters. The first support plate is evenly arranged in the vaporization section to prevent the bundle from exceeding the maximum unsupported span and causing vibration. At the same time, an overflow weir 200mm higher than the bundle is arranged at the end of the light LNG bundle. In order to prevent the accumulation of the heavy component liquid phase in the vaporizer, an opening needs to be arranged at the lower end of the overflow weir to ensure the safe and stable operation of the vaporizer.

[0086] Table 1 Light / Heavy LNG Raw Material Composition

[0087]

[0088] Note: C3+ is 0.9% iC4+, 0.9% nC4+, 0.1% iC5+, 0.1% nC5+.

[0089] By using the above device of the present invention, it can be concluded through design optimization calculation of the light hydrocarbon recovery device that the equipment cost of the above device of the present invention can be reduced by more than 20% compared with the traditional refrigeration using a propylene compressor.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A new type of LNG vaporizer assembly, characterized in that: Including composition analyzer, refrigerant buffer tank, LNG vaporizer group; The LNG vaporizer group is connected to an LNG feed pipeline; an LNG feed valve is provided on the LNG feed pipeline; the sampling point of the composition analyzer is located at the front end of the LNG feed valve; The liquid-phase refrigerant outlet of the LNG vaporizer group is connected to the refrigerant user group; the refrigerant user group is connected to the refrigerant buffer tank, and the refrigerant buffer tank is connected to the gas-phase refrigerant inlet of the LNG vaporizer group.

2. A novel LNG vaporizer assembly according to claim 1, characterized in that: The LNG vaporizer group includes a heavy LNG vaporizer and a light LNG vaporizer; The heavy LNG inlet of the heavy LNG vaporizer and the light LNG inlet of the light LNG vaporizer are connected with an LNG feed pipeline; The LNG feed valve is respectively connected to the heavy LNG inlet of the heavy LNG vaporizer or the light LNG inlet of the light LNG vaporizer; The first liquid-phase refrigerant outlet located at the light LNG vaporizer and the second liquid-phase refrigerant outlet located at the heavy LNG vaporizer are respectively connected to the refrigerant user groups; The refrigerant buffer tank is respectively connected to a first gas-phase refrigerant inlet located on the light LNG vaporizer and a second gas-phase refrigerant inlet located on the heavy LNG vaporizer.

3. A novel LNG vaporizer assembly according to claim 2, characterized in that: It also includes LNG separation tanks; The liquid phase outlet of the LNG separation tank is connected to the LNG feed pipeline; the liquid phase outlet of the LNG separation tank is provided with an LNG pump; The top of the LNG separation tank is provided with an LNG gas delivery pipe; The LNG separation tank is connected to the light LNG outlet of the light LNG vaporizer and the heavy LNG outlet of the heavy LNG vaporizer respectively.

4. A novel LNG vaporizer assembly according to claim 2, characterized in that: It also includes a refrigerant storage tank, which is respectively connected to a first liquid-phase refrigerant outlet located at the light LNG vaporizer, a second liquid-phase refrigerant outlet located at the heavy LNG vaporizer, and a refrigerant user group.

5. A novel LNG vaporizer assembly according to claim 1, characterized in that: The detection signal of the composition analyzer is used to control the opening and closing state of the LNG feed valve.

6. A novel LNG vaporizer assembly according to claim 4, characterized in that: A refrigerant pump is provided between the refrigerant storage tank and the refrigerant user group; a start-up refrigerant inlet is provided on the refrigerant storage tank for connecting the start-up refrigerant pipeline; The refrigerant pump is connected to the refrigerant user group through a circulating liquid-phase refrigerant pipe, and the refrigerant user group is connected to the refrigerant buffer tank through a circulating gas-phase refrigerant pipe; And / or, it also includes a start-up vaporizer, one end of the start-up vaporizer is connected to the refrigerant pump, and the other end of the start-up vaporizer is connected to the refrigerant buffer tank; The refrigerant user group is connected in parallel with the start-up vaporizer; And / or, the refrigerant buffer tank is connected to the light LNG vaporizer and the heavy LNG vaporizer respectively through a refrigerant valve; And / or, the detection signal of the component analyzer is used to control the opening and closing state of the refrigerant valve; And / or, when the composition analyzer detects that the C1 content of the LNG feedstock is greater than 95%, the LNG feed valve is connected to the light LNG inlet connected to the shell side of the light LNG vaporizer, and at the same time, the refrigerant valve is connected to the first gas phase refrigerant inlet connected to the tube side of the light LNG vaporizer; When the composition analyzer detects that the C1 content of the LNG raw material is less than or equal to 95%, the LNG feed valve is connected to the heavy LNG inlet connected to the heavy LNG vaporizer tube side, and at the same time, the refrigerant valve is connected to the second gas phase refrigerant inlet connected to the heavy LNG vaporizer shell side; And / or, if the processing amount of LNG raw material increases, the light LNG vaporizer and the heavy LNG vaporizer are operated simultaneously.

7. A novel LNG vaporizer assembly according to claim 2, characterized in that: The light LNG vaporizer includes a light LNG shell and a light LNG tube bundle. A plurality of U-shaped heat exchange tube bundles are arranged in the light LNG shell. The U-shaped heat exchange tubes are transversely arranged in the light LNG shell. A light LNG outlet connected to the shell side of the light LNG vaporizer is provided on the top of the light LNG shell. The LNG raw material exchanges heat with the refrigerant in the tube side in the shell side of the light LNG vaporizer.

8. A novel LNG vaporizer assembly according to claim 7, characterized in that: A first gas-phase refrigerant inlet is provided at the upper part of the pipe box of the light LNG vaporizer, and a first liquid-phase refrigerant outlet is provided at the lower part of the pipe box of the light LNG vaporizer. The first gas-phase refrigerant inlet is connected to the first liquid-phase refrigerant outlet through the pipe box, the tube sheet and the U-shaped heat exchange tube bundle; The light LNG shell of the light LNG vaporizer includes a first-stage shell, a transition-stage shell and a second-stage shell, wherein the first-stage shell and the second-stage shell are connected via the transition-stage shell; the diameter of the first-stage shell is smaller than the diameter of the second-stage shell; the lowermost end of the first-stage shell is flush with the lowermost end of the second-stage shell; The inlet end of the U-shaped heat exchange tube is located on one side of the first shell; the U-shaped end of the U-shaped heat exchange tube is located in the second shell; A plurality of staggered single-bow baffles and a first support plate are provided between the light LNG tube bundle and the light LNG shell; An overflow weir is also provided in the light LNG shell, and the overflow weir is arranged on the side close to the outer end of the U-bend; A light LNG inlet is provided at the bottom of the light LNG shell of the light LNG vaporizer, a light LNG outlet is provided at the top of the light LNG shell, and a light LNG heavy component liquid phase outlet is also provided at the bottom of the light LNG shell; the light LNG inlet is located on a side of the overflow weir close to the pipe box, and the light LNG heavy component liquid phase outlet is located on a side of the overflow weir away from the pipe box; The light LNG outlet is located at the top of the second-stage shell.

9. A novel LNG vaporizer assembly according to claim 2, characterized in that: The heavy LNG vaporizer includes a heavy LNG shell and a heavy LNG tube bundle; A plurality of U-shaped heat exchange tube bundles are arranged in the heavy LNG shell, and the U-shaped heat exchange tubes are arranged transversely in the heavy LNG shell; The gas phase refrigerant exchanges heat with the LNG raw material located in the tube side of the heavy LNG vaporizer in the shell side of the heavy LNG shell.

10. A novel LNG vaporizer assembly according to claim 9, characterized in that: A heavy LNG inlet is provided at the bottom of the pipe box of the heavy LNG vaporizer, and a heavy LNG outlet is provided at the top of the pipe box of the heavy LNG vaporizer. The heavy LNG inlet and the heavy LNG outlet are connected through the pipe box, the tube sheet and the U-shaped heat exchange tube bundle.

11. A novel LNG vaporizer assembly according to claim 10, characterized in that: An outer guide ring is provided on the shell side inlet of the heavy LNG vaporizer, and 2 to 3 air inlet grooves are evenly opened on the outer guide ring, and the gas phase refrigerant is connected with the cavity between the shell side of the heavy LNG vaporizer through the air inlet groove; A second liquid-phase refrigerant outlet is provided at the bottom of the heavy LNG shell of the heavy LNG vaporizer; A plurality of single-bow or double-bow baffles are arranged in the heavy LNG shell of the heavy LNG vaporizer, and a plurality of through holes are arranged on the baffles to support the U-shaped heat exchange tube bundle; The second gas-phase refrigerant inlet of the heavy LNG vaporizer is connected to the refrigerant buffer tank, and the second liquid-phase refrigerant outlet of the heavy LNG vaporizer is connected to the refrigerant storage tank.

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