Device for separating heavy components of liquefied natural gas

Abstract

The invention discloses a device for separating heavy components of liquefied natural gas, and relates to the technical field of natural gas, an impurity removal tower and a rectifying tower, an impurity removal mechanism for removing impurities from natural gas is arranged in the impurity removal tower, a separation mechanism for separating the heavy components of the natural gas is arranged in the rectifying tower, and a cold energy circulation mechanism is further arranged on the rectifying tower. The cold energy circulation mechanism comprises a condensation tank fixedly installed on the rectifying tower, a light component storage tank is arranged below the condensation tank, one end of the light component storage tank is provided with a gasification pipe connected with the gasifier, the other end of the light component storage tank is provided with a condensate pipe connected with the condensation tank, and the top end of the rectifying tower is further provided with a backflow pipe connected with the light component storage tank. When the LNG cold energy recovery device is used, the whole-process recovery of the LNG cold energy is realized by condensing a methane gas phase at the top of the tower and storing the methane gas phase in the light component storage tank, partially gasifying and externally transporting the methane gas phase, partially refluxing and supplementing cold, introducing a heavy component liquid phase of the tower into the heat insulation storage tank and preserving heat at low temperature by virtue of the light component storage tank.

Description

Technical Field

[0001] This invention relates to the field of natural gas technology, and more specifically to an apparatus for separating heavy components of liquefied natural gas. Background Technology

[0002] Liquefied natural gas (LNG) is a clean energy carrier formed by the cryogenic liquefaction of natural gas (-162℃, atmospheric pressure). Its core component is methane (accounting for 85%-95%), while also containing 5%-15% C2⁺ hydrocarbons (i.e. heavy components, including ethane, propane, butane, etc.).

[0003] In LNG applications, methane is mainly used as fuel gas (such as city gas and industrial fuel) for external transportation, while C2⁺ heavy components have higher added value: ethane is a key raw material for ethylene production, propane can be used to produce propylene or as liquefied petroleum gas (LPG), and butane can be used for fine chemical synthesis or gas peak shaving. Currently, the mainstream LNG heavy component separation process in industry is cryogenic distillation, which utilizes the boiling point difference between methane (boiling point -161.5℃) and C2⁺ heavy components (ethane boiling point -88.6℃, propane boiling point -42.1℃) to achieve component separation through countercurrent gas-liquid contact in the distillation column.

[0004] However, most existing heat exchange units adopt a "mixed heat exchange across the entire temperature range" design. The high-quality cold energy of LNG itself, ranging from -160℃ to -80℃, is only released once during the throttling process and is not matched to users according to the temperature range, resulting in a large amount of low-temperature smoke loss. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the purpose of this invention is to provide a device for separating heavy components of liquefied natural gas. The problem to be solved is that the heat exchange unit of the existing device is a "mixed heat exchange across the entire temperature range". The high-quality cold energy of LNG from -160℃ to -80℃ is released only once, without matching the energy use according to the temperature level, resulting in a large amount of low-temperature smoke loss.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an apparatus for separating heavy components of liquefied natural gas, comprising a purification tower and a distillation tower, wherein the purification tower is provided with a purification mechanism for removing impurities from natural gas, the distillation tower is provided with a separation mechanism for separating heavy components of natural gas, and the distillation tower is also provided with a cold energy circulation mechanism. The cold energy circulation mechanism includes a condenser fixedly installed on the distillation column, a light component storage tank is provided below the condenser, a vaporization pipe connected to a vaporizer is provided at one end of the light component storage tank, and a condensate pipe connected to the condenser is provided at the other end of the light component storage tank. The top of the distillation column is also equipped with a reflux pipe connected to a light component storage tank, and the reflux pipe and the light component storage tank are connected by a reflux pump.

[0008] As a preferred embodiment of the apparatus for separating heavy components of liquefied natural gas according to the present invention, the condenser is further provided with a condensate liner, and a heat exchange fluid is filled between the condenser and the condensate liner. The condenser is provided with an inlet and an outlet. The condensate liner is connected to the distillation column through a vapor phase pipe. The condensate pipe extends to the outside of the light component storage tank and one end of it passes through the condenser and is connected to the condensate liner.

[0009] As a preferred embodiment of the apparatus for separating heavy components of liquefied natural gas according to the present invention, the cold energy circulation mechanism further includes a heavy component storage tank, which is located below the light component storage tank. The heavy component storage tank is provided with a drain pipe and a guide pipe, and one end of the guide pipe extending outside the heavy component storage tank is connected to a distillation column.

[0010] As a preferred embodiment of the apparatus for separating heavy components of liquefied natural gas according to the present invention, the separation mechanism includes packed cylinders arranged in a distillation column, and the packed cylinders are filled with packing material. Each top of the packed cylinder is provided with a perforated tray, and the perforated tray is provided with a liquid phase distributor for spraying liquid phase. The end of the packed cylinder away from the perforated tray is also provided with a liquid receiving plate, and the liquid receiving plates are connected to each other through downcomers.

[0011] As a preferred embodiment of the apparatus for separating heavy components of liquefied natural gas according to the present invention, a conical head is fixedly installed at the bottom end of the distillation column, and a heat insulation pad is provided outside the conical head. A column base is provided on the heat insulation pad in a ring array. The distillation column is connected to the liquid guide pipe through the conical head, and the column base and the liquid guide pipe are arranged to avoid each other.

[0012] As a preferred embodiment of the apparatus for separating heavy components of liquefied natural gas according to the present invention, the top of the impurity removal tower is provided with an exhaust port, and the exhaust port is provided with a gas guide pipe connected to the distillation tower. The impurity removal tower is also provided with a natural gas conduit for introducing natural gas, and the end of the impurity removal tower away from the exhaust port is provided with a drain port.

[0013] As a preferred embodiment of the apparatus for separating heavy components of liquefied natural gas according to the present invention, the impurity removal mechanism includes a dust collection hopper fixedly installed on the inner wall of the impurity removal tower, and a water filter plate is fixedly installed at one end of the natural gas conduit passing through the dust collection hopper. The dust collection hopper is also provided with a sewage discharge pipe, and a sewage pump is installed at one end of the sewage discharge pipe extending outside the impurity removal tower.

[0014] As a preferred embodiment of the apparatus for separating heavy components of liquefied natural gas according to the present invention, the impurity removal mechanism further includes a negative pressure gas duct fixedly installed on the inner wall of the impurity removal tower, with negative pressure gas ports arranged in a row at both ends of the negative pressure gas duct, and the negative pressure gas duct being connected to an exhaust port through the negative pressure gas ports.

[0015] As a preferred embodiment of the apparatus for separating heavy components of liquefied natural gas according to the present invention, the impurity removal mechanism further includes a stepped cone hood fixedly installed on the negative pressure gas duct, and the stepped cone hood corresponds to one end of the natural gas duct protruding from the filter plate. The inner wall of the impurity removal tower is also provided with a dust filter membrane, and the dust filter membrane is located between the negative pressure gas duct and the stepped cone hood.

[0016] In summary, the present invention has at least one of the following beneficial effects: 1. This invention achieves full-process recovery of LNG cold energy by condensing the gaseous methane at the top of the tower into a light component storage tank, partially vaporizing and transporting it outwards, and partially refluxing it for recooling, while introducing the heavy component liquid phase at the bottom of the tower into an insulated storage tank and using the light component storage tank for low-temperature insulation.

[0017] 2. This invention achieves efficient countercurrent contact between gas and liquid by mixing pre-cooled clean feed gas with reflux liquid in a distillation column. Combined with the boiling point difference between light and heavy components and the maintenance of balance in the column by the reflux liquid, heavy components in natural gas can be accurately separated.

[0018] 3. This invention, by using a water filter plate, stepped cone hood, and dust filter membrane for graded impurity removal in the impurity removal tower, and in conjunction with a negative pressure air duct to accelerate airflow, can comprehensively remove large particulate impurities, free water, and fine dust from LNG feedstock, and output feedstock gas with a cleanliness level that meets the standards. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0020] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a cross-sectional perspective view of the present invention; Figure 3 This is a structural diagram of the cold energy circulation mechanism of the present invention; Figure 4 This is a cross-sectional view of the impurity removal tower and impurity removal mechanism of the present invention in conjunction with each other. Figure 5 This is a structural diagram showing the assembly of the distillation column and separation mechanism of the present invention. Figure 6This is a structural diagram of the separation mechanism of the present invention.

[0021] Explanation of reference numerals in the attached figures: 1. Impurity removal tower; 101. Exhaust port; 102. Natural gas conduit; 103. Drain outlet; 2. Distillation tower; 201. Gas delivery pipe; 3. Condensate tank; 301. Water inlet; 302. Water outlet; 4. Light component storage tank; 401. Vaporization pipe; 402. Condensate pipe; 5. Reflux pipe; 6. Reflux pump; 7. Condensate liner; 701. Vapor phase pipe; 8. Heavy component storage tank; 801. Drain pipe; 802. Liquid guide pipe; 9. Packing cylinder; 10. Sieve tray; 11. Liquid phase distributor; 12. Liquid receiving tray; 13. Downcomer; 14. Conical head; 1401. Heat insulation pad; 1402. Tower base; 15. Dust collection hopper; 1501. Water filter plate; 1502. Sewage pipe; 16. Sewage pump; 17. Negative pressure air duct; 1701. Negative pressure air inlet; 18. Stepped cone cover; 19. Dust filter membrane. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention discloses an apparatus for separating heavy components of liquefied natural gas. Example

[0024] Reference Figure 1-6This invention provides a first embodiment of an apparatus for separating heavy components of liquefied natural gas (LNG). The apparatus includes a purification tower 1 and a distillation tower 2. The purification tower 1 is equipped with a purification mechanism for removing impurities from the natural gas. The distillation tower 2 is equipped with a separation mechanism for separating heavy components of the natural gas. The distillation tower 2 also includes a cold energy circulation mechanism, which includes a condenser tank 3 fixedly installed on the distillation tower 2. Below the condenser tank 3 is a light component storage tank 4. One end of the light component storage tank 4 is connected to a vaporization pipe 401 connected to a vaporizer, and the other end is connected to a condensate pipe 402 connected to the condenser tank 3. The top of the distillation tower 2 is also equipped with a reflux pipe 5 connected to the light component storage tank 4, and the reflux pipe 5 and the light component storage tank 4 are connected by a reflux pump 6. The purification tower 1 and the distillation tower 2 are connected in series. Furthermore, the impurity removal tower 1 can specifically remove contaminants such as dust, mechanical impurities, and free water from the LNG feedstock through the impurity removal mechanism. The distillation tower 2, as the separation core, can achieve precise separation of methane (light component) and C2⁺ heavy component through the separation mechanism based on the gas-liquid mass transfer principle. In order to maximize the utilization of cold energy in the LNG gasification process, the condenser 3 is used to condense the light component gas phase escaping from the top of the distillation tower 2, and the light component storage tank 4 is used to temporarily store the condensed light component liquid, which is mainly composed of methane. The vaporization pipe 401 can vaporize the light component liquid and output it as fuel gas. The condensate pipe 402 guides part of the unvaporized condensate in the light component storage tank 4 back to the condenser 3 to realize cold energy recovery. The reflux pipe 5 can pressurize part of the condensate in the light component storage tank 4 and send it back to the distillation tower 2 as reflux liquid to maintain the gas-liquid balance in the tower and improve the separation efficiency.

[0025] The condenser 3 also includes a condensate liner 7, with heat exchange fluid filling the space between the condenser 3 and the condensate liner 7. The condenser 3 has an inlet 301 and an outlet 302. The condensate liner 7 is connected to the distillation column 2 via a vapor phase pipe 701. The condensate pipe 402 extends to the outside of the light component storage tank 4 and passes through the condenser 3, connecting to the condensate liner 7. The condenser 3 adopts a "dual-chamber" structural design, with the nested condensate liner 7 made of corrosion-resistant stainless steel, forming an independent vapor phase condensation chamber. This avoids direct contact between the light component vapor phase and the external heat exchange medium during condensation, preventing contamination. The condensation is achieved through the circulation of the heat exchange fluid. To achieve cold energy transfer, the inlet 301 and outlet 302 are used to connect to the external heat exchange liquid circulation pipeline. After the heat exchange liquid absorbs the heat of the gas phase in the condensate liner 7, it can be discharged and cooled through the outlet 302, and then reinjected through the inlet 301 to maintain condensation efficiency. The gas phase pipe 701 can guide the rising light component gas phase (temperature -120℃~-110℃) in the distillation column into the condensate liner 7. The condensate pipe 402 can allow the light component liquid (around -115℃) formed by condensation in the condensate liner 7 to flow into the light component storage tank 4 through the condensate pipe 402 by gravity, while reducing the loss of cold energy during the transportation process.

[0026] The cold energy circulation mechanism also includes a heavy component storage tank 8, which is located below the light component storage tank 4. The heavy component storage tank 8 is equipped with a drain pipe 801 and a guide pipe 802, and the end of the guide pipe 802 extending outside the heavy component storage tank 8 is connected to the distillation column 2. The heavy component storage tank 8 is used to temporarily store the C2⁺ heavy component liquid phase separated from the distillation column 2. It adopts a double-layer vacuum insulation structure, which can maintain a low-temperature storage environment of -45℃ to -90℃ to prevent the heavy components from being heated and vaporized. The drain pipe 801 is equipped with a shut-off valve to transport the purified ethane, propane and other heavy components to the chemical plant or subsequent storage equipment as needed. The guide pipe 802 is equipped with a flow regulating valve, which can accurately control the rate at which the heavy component liquid phase separated in the distillation column 2 is introduced into the heavy component storage tank 8, and maintain the low-temperature storage environment of the heavy component storage tank 8 through the lower-temperature light component liquid in the light component storage tank 4.

[0027] The separation mechanism includes packed cylinders 9 arranged in a distillation column 2, each filled with packing material. Each packed cylinder 9 has a perforated tray 10 at its top, and a liquid phase distributor 11 for spraying liquid phase is installed on the perforated tray 10. A liquid receiving plate 12 is also provided at the end of the packed cylinder 9 away from the perforated tray 10, and the liquid receiving plates 12 are connected by downcomers 13. The packing material increases the gas-liquid contact area and enhances mass transfer. The liquid phase distributor 11 has a porous spray structure, and its inlet is connected to the feed pipe and reflux pipe 5 of the distillation column 2, allowing it to spray LNG feed liquid (after impurity removal and cooling). The liquid is sprayed evenly onto the perforated tray 10 at temperatures ranging from -100℃ to -130℃ to form a stable liquid layer. The receiving tray 12 has an arc-shaped groove structure to receive the liquid phase flowing down from the upper downcomer 13 and evenly guide it into the lower packing cylinder 9. The upper end of the downcomer 13 is higher than the liquid layer height of the perforated tray 10 (forming a liquid seal), and the lower end extends into the lower receiving tray 12. This allows the liquid phase to flow orderly from top to bottom between the trays, while preventing the gas phase from flowing through the downcomer 13. This ensures countercurrent contact between gas and liquid in the tower, achieving efficient separation through the boiling point difference between methane and C2⁺ heavy components.

[0028] A conical head 14 is fixedly installed at the bottom of the distillation column 2, and a heat insulation pad 1401 is provided on the outside of the conical head 14. A column base 1402 distributed in a ring array is provided on the heat insulation pad 1401. The distillation column 2 is connected to the liquid guide pipe 802 through the conical head 14, and the column base 1402 and the liquid guide pipe 802 are arranged to avoid each other. The conical structure of the conical head 14 allows the heavy component liquid phase (density greater than that of the light component) separated in the column to collect along the inner wall of the head to the bottom outlet, reducing the liquid phase residue at the bottom of the column. The heat insulation pad 1401 can effectively block the cold energy in the column from being conducted to the outside through the head, maintaining the operating temperature of about -40°C at the bottom of the column. The heavy component liquid phase at the bottom of the column can be smoothly introduced into the heavy component storage tank 8 through the liquid guide pipe 802.

[0029] The top of the impurity removal tower 1 is provided with an exhaust port 101, and the exhaust port 101 is provided with a gas guide pipe 201 connected to the distillation tower 2. The impurity removal tower 1 is also provided with a natural gas conduit 102 for introducing natural gas. The end of the impurity removal tower 1 away from the exhaust port 101 is provided with a drain port 103. The exhaust port 101 is used to discharge the clean LNG feed gas after impurity removal treatment. The gas guide pipe 201 is provided with a check valve and a flow regulating valve to control the delivery rate of the feed gas and prevent gas backflow. The natural gas conduit 102 is used to introduce the LNG feed gas to be treated (containing dust, moisture and other impurities) into the impurity removal tower 1 after the liquefied natural gas is vaporized by the pump. The drain port 103 is equipped with a drain valve to periodically discharge the free water and some liquid impurities separated during the impurity removal process to avoid the accumulation of liquid in the impurity removal tower 1 and affect the impurity removal effect.

[0030] The impurity removal mechanism includes a dust collection hopper 15 fixedly installed on the inner wall of the impurity removal tower 1, and a filter plate 1501 fixedly installed at one end of the natural gas conduit 102 passing through the dust collection hopper 15. The dust collection hopper 15 is also equipped with a sewage pipe 1502, and a sewage pump 16 is installed at the end of the sewage pipe 1502 extending outside the impurity removal tower 1. The dust collection hopper 15 can collect solid pollutants such as dust and mechanical impurities separated from natural gas. The filter plate 1501 is set horizontally, which can initially intercept large particulate impurities carried in LNG raw materials. The intercepted impurities fall into the dust collection hopper 15, and the free water is discharged through the drain outlet 103. The sewage pump 16 can periodically pump the impurities (dust and sewage mixture) collected in the dust collection hopper 15 out of the impurity removal tower 1 to achieve centralized treatment of impurities.

[0031] The impurity removal mechanism also includes a negative pressure gas duct 17 fixedly installed on the inner wall of the impurity removal tower 1. Negative pressure gas ports 1701 are arranged at both ends of the negative pressure gas duct 17. The negative pressure gas duct 17 is connected to the exhaust port 101 through the negative pressure gas ports 1701. The negative pressure gas duct 17 can provide negative pressure to the impurity removal tower 1 through an external pump. When the gas is drawn out through the exhaust port 101, a negative pressure environment is formed in the negative pressure gas duct 17. The suction force generated through the negative pressure gas ports 1701 accelerates the flow of natural gas in the impurity removal tower 1.

[0032] The impurity removal mechanism also includes a stepped cone shroud 18 fixedly installed on the negative pressure gas duct 17, and the stepped cone shroud 18 corresponds to one end of the natural gas conduit 102 that protrudes from the filter plate 1501. The inner wall of the impurity removal tower 1 is also provided with a dust filter membrane 19, and the dust filter membrane 19 is located between the negative pressure gas duct 17 and the stepped cone shroud 18. The stepped cone shroud 18 is a multi-layered conical metal shroud. When the LNG raw material is sprayed from the end of the natural gas conduit 102, the airflow impacts the stepped cone shroud 18, which can change the airflow direction to form a vortex. The centrifugal force is used to separate the fine dust particles remaining in the gas. The dust filter membrane 19 is a high-molecular low-temperature resistant filter membrane that can comprehensively filter the small dust particles and free water that are not separated in the airflow. Under specific conditions, the dust filter membrane 19 can be replaced by a molecular sieve in the prior art to achieve the filtration of impurities.

[0033] In the process of separating and processing liquefied natural gas using this device, the LNG raw material to be processed is transported through the natural gas conduit 102 and an external pump to vaporize the LNG and introduce it into the impurity removal tower 1. The raw gas flows upward and impacts the stepped cone 18 on the negative pressure air passage 17. After the airflow hits the stepped cone 18, it changes direction and forms a vortex. The centrifugal force is used to throw the fine dust particles remaining in the raw gas toward the inner wall of the impurity removal tower 1, achieving secondary dust removal. Subsequently, the raw gas passes through the dust filter membrane 19 located between the stepped cone 18 and the negative pressure air passage 17 to further filter out fine dust and trace amounts of free water. The water filter plate 1501 separates the free water. The intercepted impurity mixture is pumped out of the impurity removal tower 1 periodically by the sewage pump 16 through the sewage pipe 1502 at the bottom of the dust collection hopper 15, completing the initial purification. Meanwhile, the external negative pressure system draws air through the exhaust port 101, creating a negative pressure environment in the negative pressure air passage 17. The negative pressure air port 1701 generates suction, accelerating the flow rate of the raw material gas in the impurity removal tower 1, avoiding dead air zones, and ensuring that the raw material gas is fully purified by the filter dust membrane 19. Finally, the clean raw material gas is collected through the negative pressure air passage 17 to the exhaust port 101 and sent into the distillation tower 2 through the gas guide pipe 201. The light component gas phase enriched at the top of the distillation column 2 is introduced into the condensate liner 7 of the condenser 3 through the gas phase pipe 701. After absorbing the heat of the light component gas phase in the condensate liner 7 through the heat exchange liquid between the condenser 3 and the condensate liner 7, it is discharged and cooled through the outlet 302 and then circulated back into the jacket to form a continuous cold energy transfer. The light component gas phase is cooled to about -115°C in the condensate liner 7 by the heat exchange liquid and condenses into light component condensate. The condensate flows into the light component storage tank 4 through the condensate pipe 402 for temporary storage, completing the transfer of cold energy from the gas phase to the heat exchange liquid. The light component condensate in the light component storage tank 4 is transported to the external vaporizer via the vaporization pipe 401 and vaporized as fuel gas. The other part is sent back to the distillation column 2 via the return pipe 5 and the return pump 6. The low temperature condensate (around -115℃) in the light component storage tank 4 dissipates heat through the tank body, providing a low temperature environment for the heavy component storage tank 8 below, helping to maintain the insulation effect of the heavy component storage tank 8 and reducing its cooling loss. The liquid distributor 11 evenly sprays the condensate transported by the reflux pipe 5 onto the perforated tray 10, and after mixing the feed liquid and reflux liquid, a stable liquid layer is formed on the surface of the perforated tray 10. The light components in the feed liquid (methane, boiling point -161.5℃) have low boiling points and are rapidly vaporized under the action of the temperature gradient in the column (top of the column -120℃ to bottom of the column -40℃), forming a gas phase that flows upward. The heavy components (C2⁺, ethane boiling point -88.6℃, propane boiling point -42.1℃, etc.) have high boiling points and remain in the perforated tray in liquid form. At position 10, preliminary gas-liquid separation is completed. The liquid phase flows downward along the surface of the packing and comes into full contact with the light component gas phase that continues to flow upward in the gaps between the packing. Through mass transfer, further separation occurs: the heavy components that are not absorbed in the gas phase are captured by the liquid phase on the surface of the packing, and the light components that are not vaporized in the liquid phase are vaporized again and rise, achieving secondary mass transfer. Finally, the heavy component liquid phase (temperature -40℃~30℃, mainly C2⁺) at the bottom of the distillation column 2 is introduced into the heavy component storage tank 8 through the liquid guide pipe 802 along the conical head 14, and can be discharged externally through the drain pipe 801.

[0034] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An apparatus for separating heavy components of liquefied natural gas, characterized in that: It includes a purification tower (1) and a distillation tower (2). The purification tower (1) is equipped with a purification mechanism for removing impurities from natural gas, and the distillation tower (2) is equipped with a separation mechanism for separating heavy components of natural gas. The distillation tower (2) is also equipped with a cold energy circulation mechanism. The cold energy circulation mechanism includes a condenser (3) fixedly installed on the distillation column (2), a light component storage tank (4) is provided below the condenser (3), a vaporization pipe (401) connected to the vaporizer is provided at one end of the light component storage tank (4), and a condensate pipe (402) connected to the condenser (3) is provided at the other end of the light component storage tank (4). The top of the distillation column (2) is also provided with a reflux pipe (5) connected to the light component storage tank (4), and the reflux pipe (5) and the light component storage tank (4) are connected by a reflux pump (6).

2. The apparatus for separating heavy components of liquefied natural gas according to claim 1, characterized in that, The condenser (3) is also provided with a condensate liner (7), and a heat exchange liquid is filled between the condenser (3) and the condensate liner (7). The condenser (3) is provided with an inlet (301) and an outlet (302). The condensate liner (7) is connected to the distillation column (2) through a vapor phase pipe (701). The condensate pipe (402) extends to the outside of the light component storage tank (4) and passes through the condenser (3) and is connected to the condensate liner (7).

3. The apparatus for separating heavy components of liquefied natural gas according to claim 2, characterized in that, The cold energy circulation mechanism also includes a heavy component storage tank (8), which is located below the light component storage tank (4). The heavy component storage tank (8) is provided with a drain pipe (801) and a guide pipe (802), and the guide pipe (802) extends to one end outside the heavy component storage tank (8) and is connected to the distillation column (2).

4. The apparatus for separating heavy components of liquefied natural gas according to claim 1, characterized in that, The separation mechanism includes packing cylinders (9) arranged in a distillation column (2), and the packing cylinders (9) are filled with packing. Each packing cylinder (9) has a perforated plate (10) at its top, and the perforated plate (10) is provided with a liquid phase distributor (11) for spraying liquid phase. The end of the packing cylinder (9) away from the perforated plate (10) is also provided with a liquid receiving plate (12), and the liquid receiving plates (12) are connected to each other through downcomers (13).

5. The apparatus for separating heavy components of liquefied natural gas according to claim 1, characterized in that, The bottom end of the distillation column (2) is fixedly installed with a conical head (14), and a heat insulation pad (1401) is provided outside the conical head (14). A column base (1402) is provided on the heat insulation pad (1401) in a ring array. The distillation column (2) is connected to the liquid guide pipe (802) through the conical head (14), and the column base (1402) and the liquid guide pipe (802) are arranged to avoid each other.

6. The apparatus for separating heavy components of liquefied natural gas according to claim 1, characterized in that, The top of the impurity removal tower (1) is provided with an exhaust port (101), and the exhaust port (101) is provided with a gas guide pipe (201) connected to the distillation tower (2). The impurity removal tower (1) is also provided with a natural gas conduit (102) for introducing natural gas. The end of the impurity removal tower (1) away from the exhaust port (101) is provided with a drain port (103).

7. The apparatus for separating heavy components of liquefied natural gas according to claim 6, characterized in that, The impurity removal mechanism includes a dust collection hopper (15) fixedly installed on the inner wall of the impurity removal tower (1), and a water filter plate (1501) is fixedly installed at one end of the natural gas conduit (102) passing through the dust collection hopper (15). A sewage pipe (1502) is also provided on the dust collection hopper (15), and a sewage pump (16) is installed at one end of the sewage pipe (1502) extending outside the impurity removal tower (1).

8. The apparatus for separating heavy components of liquefied natural gas according to claim 7, characterized in that, The impurity removal mechanism also includes a negative pressure air passage (17) fixedly installed on the inner wall of the impurity removal tower (1). The negative pressure air passage (17) has negative pressure air ports (1701) arranged at both ends. The negative pressure air passage (17) is connected to the exhaust port (101) through the negative pressure air ports (1701).

9. The apparatus for separating heavy components of liquefied natural gas according to claim 7, characterized in that, The impurity removal mechanism also includes a stepped cone hood (18) fixedly installed on the negative pressure gas duct (17), and the stepped cone hood (18) corresponds to one end of the natural gas conduit (102) protruding from the filter plate (1501). The inner wall of the impurity removal tower (1) is also provided with a dust filter membrane (19), and the dust filter membrane (19) is located between the negative pressure gas duct (17) and the stepped cone hood (18).

Images