Inert gas system of chemical tanker and chemical tanker

Abstract

The invention relates to a chemical tanker inert gas system and a chemical tanker. The system comprises an inert gas generating device, a high-pressure inert gas cylinder group, an inert gas tank device, a first inert gas buffer tank, a second inert gas buffer tank and a pressure regulating valve box, wherein the first inert gas buffer tank, the second inert gas buffer tank and the pressure regulating valve box are arranged along a first gas supply pipeline; inert gas generated by the inert gas generating device flows through the first inert gas buffer tank along the first gas supply pipeline and then is sent to the pressure regulating valve box; inert gas generated by the high-pressure inert gas bottle group and the inert gas tank device flows through the second inert gas buffer tank and then is conveyed to the pressure regulating valve box along the first gas supply pipeline; the pressure regulating valve box achieves purging through an inert gas purging pipeline, and air cushion protection is formed on the top of the cargo hold through an inert gas supplementing pipeline. Through multiple inert gas sources, the inert gas supply stability and the variety of carried goods types are improved, the pipeline arrangement is simplified through the shared pipeline, and the cost is saved.

Description

Technical Field

[0001] The present invention relates to the field of chemical tankers, and in particular to an inert gas system of a chemical tanker and a chemical tanker. Background Art

[0002] Chemical tankers are tankers that are specially designed to carry toxic, flammable, volatile, and highly corrosive liquid chemicals. They are usually classified into Class I, Class II, and Class III according to the degree of hazard of the chemicals they carry. Class I is the most harmful to the environment, and its tank capacity must be less than 1,250 m 3 ; Level II is relatively less harmful to the environment, and its cargo hold volume must be less than 3000m 3 ; Class III cargoes are those with relatively less environmental hazards. The cargo hold structure is similar to that of general product oil tankers and there is generally no restriction on the maximum hold capacity.

[0003] In order to be able to simultaneously load the above-mentioned Level I, Level II and Level III liquid chemicals of various varieties, different properties and different system configuration requirements, chemical tankers are designed to have many small watertight cargo holds. Taking the 38,000-ton chemical tankers, which are currently being built in large quantities, as an example, the number of cargo hold sub-compartments ranges from 30 to 50, and the liquid cargo system adopts a one-tank-one-pump system, which can load and unload 5-6 grades of liquid chemicals at the same time.

[0004] The inert gas system is a typical system on chemical tankers. Its main function is to control the environment of liquid cargo tanks. Some liquid cargoes require isolation from oxygen, water vapor and / or other gases to prevent oxidation, chemical reactions and changes in chemical quality. The inert gas system forms a top air cushion in the cargo hold by providing inert gas. In addition, inert gas can also be used for fire prevention and explosion prevention. The cargo hold inerted with inert gas is safer during operations such as tank washing. After tank washing, the dry air generated by the inert system can be used to quickly ventilate and dry the cargo hold. In addition, high-pressure inert gas can also be used to sweep residual liquid cargo remaining in pipelines or liquid cargo tanks.

[0005] Common inert gases such as nitrogen are prepared / provided by nitrogen generators and then provided to cargo holds and other areas through pipeline systems. Currently, the source of inert gas in the inert gas system is relatively single, the safety of the inert gas system is relatively low, and it cannot adapt well to the needs of chemical tankers for loading diverse types of liquid cargoes. Summary of the invention

[0006] In order to increase the types of liquid cargoes loaded on chemical tankers and improve the safety of inert gas systems, the present invention provides an inert gas system for a chemical tanker and a chemical tanker, which expand the source range and purity range of the inert gas, simplify the pipeline layout, and save construction costs.

[0007] The technical objectives of the present invention are achieved through the following technical solutions:

[0008] A chemical tanker inert gas system, comprising:

[0009] Inert gas generating device, used to produce inert gas and provide dry air;

[0010] High-pressure inert gas cylinder group, used to load pressurized gaseous inert gas;

[0011] Inert gas tank device, used to carry liquid inert gas;

[0012] A first gas supply pipeline, comprising a first inert gas buffer tank, a second inert gas buffer tank, and a pressure regulating valve box arranged along the first gas supply pipeline;

[0013] The high-pressure inert gas cylinder group and the inert gas tank device are connected with a high-pressure and high-purity supply pipe, and the high-pressure inert gas cylinder group and the inert gas tank device respectively provide inert gas to the second inert gas buffer tank through the high-pressure and high-purity supply pipe;

[0014] The inert gas generated by the inert gas generating device flows through the first inert gas buffer tank along the first gas supply pipeline and is then delivered to the pressure regulating valve box; the inert gas generated by the high-pressure inert gas bottle group and the inert gas tank device flows through the second inert gas buffer tank and is then delivered to the pressure regulating valve box along the first gas supply pipeline;

[0015] An inert gas purge pipeline, used to connect the pressure regulating valve box to obtain inert gas from the first gas supply pipeline for purging the cargo pump and / or cargo pipeline;

[0016] The inert gas supply pipeline is used to connect the pressure regulating valve box to obtain inert gas from the first gas supply pipeline to form an air cushion protection on the top of the cargo hold.

[0017] Furthermore, the purity of the inert gas provided by the high-pressure inert gas cylinder group and the inert gas tank device is ≥99.99%, and the purity of the inert gas produced by the inert gas generating device is ≥95% and ≤99.9%.

[0018] Furthermore, the inert gas generating device is also connected to a second gas supply pipeline, through which the inert gas generating device transports inert gas to the cargo manifold area of ​​the chemical tanker to inertate the cargo hold or transports dry air to dry the cargo hold; the gas pressure intensity of the inert gas transported by the second gas supply pipeline is lower than the gas pressure intensity of the inert gas transported by the first gas supply pipeline.

[0019] Furthermore, the inert gas generating device is also connected to a deck miscellaneous air pipe, and the inert gas generating device provides dry air to the deck area through the deck miscellaneous air pipe.

[0020] Furthermore, the inert gas is nitrogen, and the inert gas generating device includes an air compressor unit, an air buffer tank, a filter unit, an air dryer, and a nitrogen generator; the air compressor unit, the air buffer tank, and the filter unit are connected in sequence to generate dry air; the air compressor unit, the air buffer tank, the filter unit, and the nitrogen generator are connected in sequence to separate nitrogen from the air; the air compressor unit, the air buffer tank, and the air dryer are connected in sequence to generate dry air.

[0021] Furthermore, the high-pressure inert gas bottle group includes a high-pressure nitrogen bottle, a gas supply main pipe, and a pressure reducing valve arranged on the gas supply main pipe. The high-pressure nitrogen bottle is connected to the high-pressure and high-purity supply pipe through the gas supply main pipe; the gas supply main pipe is also connected to a high-pressure and high-purity supply sub-pipe after passing through the pressure reducing valve, and the high-purity supply sub-pipe is connected to the pressure regulating valve box.

[0022] Furthermore, the inert gas tank device includes a liquid nitrogen tank, a liquid nitrogen evaporator, and a liquid nitrogen filling manifold. The liquid nitrogen tank is used to store liquid nitrogen and provide liquid nitrogen to the liquid nitrogen evaporator. The liquid nitrogen filling manifold is used to replenish liquid nitrogen to the liquid nitrogen tank. The liquid nitrogen evaporator is used to convert the liquid nitrogen provided by the liquid nitrogen tank into nitrogen gas.

[0023] Furthermore, the second air supply pipeline includes a double-stop air-permeable valve, a pressure vacuum protection device, an isolation valve and a blind flange arranged along the conveying path of the second air supply pipeline.

[0024] Further, the inert gas purge pipeline includes a purge pipeline and a stop check valve arranged on the purge pipeline;

[0025] The inert gas supply pipeline comprises a supply pipeline and a cut-off vent valve arranged on the supply pipeline.

[0026] The present invention also provides a chemical tanker, on which the above-mentioned inert gas system is arranged; the inert gas generating device is arranged in the engine room in the safe area of ​​the chemical tanker, the high-pressure inert gas bottle group and the inert gas tank device are arranged on the open deck in the dangerous area of ​​the chemical tanker and are located in the bow direction of the cargo manifold area; the inert gas supply pipeline is connected to the ventilation tower on the chemical tanker, the ventilation tower is distributed on the open deck in the dangerous area of ​​the chemical tanker and is located on the left front side, the right front side, the left rear side and the right rear side of the open deck; the ventilation tower is connected to the cargo hold ventilation pipe of the cargo hold through a hose, the hose is provided with a stop check valve with a quick connector, and the cargo hold ventilation pipe delivers the inert gas to the top of the cargo hold to form a top air cushion.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention forms multiple sources of inert gas through an inert gas generating device, a high-pressure inert gas bottle group and an inert gas tank device, thereby improving the stability of inert gas supply and the diversity of transported cargo types; the inert gas generating device, the high-pressure inert gas bottle group and the inert gas tank device are mutually redundant, and can replenish gas for goods with relatively low inert gas purity requirements to form a top air cushion protection; the high-pressure inert gas bottle group and the inert gas tank device are mutually redundant, and can replenish gas for goods with relatively high inert gas purity requirements (≥99.99%) to form a top air cushion protection.

[0029] 2. In the present invention, the first inert gas buffer tank and the second inert gas buffer tank are used to buffer and stabilize the low-purity nitrogen and high-purity nitrogen respectively, and then the first gas supply pipeline is shared for inert gas supply, which not only improves safety but also simplifies pipeline layout, and at the same time can also reduce space occupancy and reduce construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the arrangement of the inert gas system of a chemical tanker in the present invention.

[0031] Figure 2 It is a schematic diagram of the composition of the inert gas generating device in the present invention.

[0032] Figure 3 It is a schematic diagram of the arrangement of the high-pressure inert gas bottle group and the inert gas tank device in the present invention.

[0033] In the figure:

[0034] 1. Inert gas generator; 2. High-pressure inert gas bottle group; 3. Inert gas tank device; 4. Air compressor unit; 5. Air buffer tank; 6. Filter unit; 7. Nitrogen generator; 8. Air dryer; 9. High-pressure nitrogen bottle; 10. Gas supply main; 11. Pressure reducing valve; 12. Liquid nitrogen tank; 13. Liquid nitrogen evaporator; 14. Liquid nitrogen filling manifold; 15. Second gas supply pipeline; 16. Double stop breather valve; 17. Pressure vacuum protection device; 18. Isolation valve; 19. Blind flange; 2 0. The first air supply pipeline; 21. The first inert gas buffer tank; 22. The second inert gas buffer tank; 23. The pressure regulating valve box; 24. The high-pressure and high-purity supply pipe; 25. The purge pipeline; 26. The stop check valve; 27. The air supply pipeline; 28. The stop vent valve; 29. ​​The stop check valve with quick connector; 30. The deck miscellaneous air pipe; 31. The chemical tanker; 32. The cargo manifold area; 33. The high-pressure and high-purity supply auxiliary pipe; 34. The engine room in the safe area; 35. The open deck in the dangerous area. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below in conjunction with specific embodiments:

[0036] A chemical tanker inert gas system, inert gas such as nitrogen, such as Figure 1 As shown, including:

[0037] An inert gas generator 1 is used to produce nitrogen and provide dry air;

[0038] High-pressure inert gas bottle group 2, used to load pressurized nitrogen;

[0039] An inert gas tank device 3, used to load liquid nitrogen;

[0040] The first gas supply pipeline 20 includes a first inert gas buffer tank 21, a second inert gas buffer tank 22, and a pressure regulating valve box 23 arranged along the first gas supply pipeline; in this embodiment, the purity of the nitrogen in the first inert gas buffer tank is ≥95% and less than 99.9%, and the purity of the nitrogen in the second inert gas buffer tank is ≥99.9%.

[0041] The high-pressure inert gas cylinder group 2 and the inert gas tank device 3 are connected with a high-pressure and high-purity supply pipe 24, and the high-pressure inert gas cylinder group 2 and the inert gas tank device 3 respectively provide nitrogen to the second inert gas buffer tank 22 through the high-pressure and high-purity supply pipe 24;

[0042] The nitrogen generated by the inert gas generating device 1 flows along the first gas supply pipeline 20 through the first inert gas buffer tank 21 for buffering and pressure stabilization, and then is sent to the pressure regulating valve box 23 through the first gas supply pipeline 20; the nitrogen generated by the high-pressure inert gas bottle group 2 and the inert gas tank device 3 flows through the second inert gas buffer tank for buffering and pressure stabilization, and then is sent to the pressure regulating valve box 23 along the first gas supply pipeline 20;

[0043] The inert gas purge pipeline is used to connect to the pressure regulating valve box 23 to obtain nitrogen from the first gas supply pipeline 20 for purging the cargo pump and / or cargo pipeline; the inert gas purge pipeline includes a purge pipeline 25 and a stop check valve 26 arranged on the purge pipeline 25, and the purge pipeline is connected to the pressure regulating valve box 23.

[0044] The inert gas supply pipeline is used to connect to the pressure regulating valve box 23 to obtain nitrogen from the first air supply pipeline 20 to form an air cushion protection on the top of the cargo hold; the inert gas supply pipeline includes an air supply pipeline 27 and a shut-off air valve 28 arranged on the air supply pipeline 27, and the air supply pipeline 27 is connected to the pressure regulating valve box 23.

[0045] Since the high-pressure inert gas cylinder group 2 and the inert gas tank device 3 use finished inert gas, they can provide inert gas or liquefied inert gas with higher purity. The inert gas generating device 1 adopts an on-site preparation method, and the purity of its inert gas is lower than that of the finished inert gas and liquefied inert gas. In this embodiment, the purity of nitrogen provided by the high-pressure inert gas cylinder group 2 and the inert gas tank device 3 is ≥99.99%, and the purity of nitrogen produced by the inert gas generating device 1 is 95%-99.9%.

[0046] More specifically, the inert gas generating device 1 is as follows Figure 2 As shown, it includes an air compressor unit 4, an air buffer tank 5, a filter unit 6, an air dryer 8, and a nitrogen generator 7; the air compressor unit, the air buffer tank, and the filter unit are connected in sequence to generate dry air; the air compressor unit 4, the air buffer tank 5, the filter unit 6, and the nitrogen generator 7 are connected in sequence through pipelines to separate nitrogen from the air; the air compressor unit 4, the air buffer tank 5, and the air dryer 8 are connected in sequence to generate dry air.

[0047] The air compressor unit 4 is also called an air compressor unit. It outputs compressed air through several air compressors. The compressed air enters the air buffer tank 5 for buffering and then outputs stable compressed air. The compressed air is filtered through the filter unit 6 to remove oil, water, dust, etc. in the compressed air to generate dry air. The nitrogen generator is such as an adsorption nitrogen generator (PSA). The nitrogen generator is equipped with an adsorption tower equipped with a carbon molecular sieve. The carbon molecular sieve adsorbs oxygen in the air. After removing the oxygen, the main gas component is nitrogen, and the concentration of nitrogen is 95%-99.9%. The air buffer tank 5 outputs stable compressed air, which is dried by the air dryer 8 to form dry air. The preparation of nitrogen by compressed air belongs to the prior art. The prior art is as follows: Zang Dawei, Chen Li, Wang Kun, etc. Application of full nitrogen system on 55000t chemical ship [J]. Ship power plant, 2017, No. 6.

[0048] More specifically, Figure 3 As shown, the high-pressure inert gas cylinder group 2 includes a plurality of high-pressure nitrogen cylinders 9, a gas supply main pipe 10, and a pressure reducing valve 11 arranged on the gas supply main pipe 10, which is connected to the high-pressure and high-purity supply pipe through the gas supply main pipe 10. The high-pressure nitrogen cylinder 9 stores 200 bar of high-pressure nitrogen. The high-pressure nitrogen cylinder group 2 outputs 8 bar of high-purity nitrogen after reducing pressure through the pressure reducing valve 11, and then is transported to the second inert gas buffer tank 22 by the high-pressure and high-purity supply pipe for buffering and pressure stabilization. The gas supply main pipe 10 is also connected to a high-pressure and high-purity supply sub-pipe 33 after passing through the pressure reducing valve 11. The high-purity supply sub-pipe 33 is connected to the pressure regulating valve box 23. After pressure regulation by the pressure regulating valve box 23, 0.17 bar of high-purity low-pressure nitrogen can be output. The 0.17 bar of high-purity low-pressure nitrogen is transmitted through the air supply pipeline 27, and finally forms an air cushion protection on the top of the cargo hold.

[0049] The inert gas tank device 3 includes a liquid nitrogen tank 12, a liquid nitrogen evaporator 13, and a liquid nitrogen filling manifold 14. The liquid nitrogen tank 12 is used to store liquid nitrogen and provide liquid nitrogen to the liquid nitrogen evaporator 13. The liquid nitrogen filling manifold 14 is used to replenish liquid nitrogen to the liquid nitrogen tank 12. The liquid nitrogen evaporator 13 is used to convert the liquid nitrogen provided by the liquid nitrogen tank 12 into nitrogen gas. In this embodiment, the liquid nitrogen evaporator 13 outputs 8 bar high-purity nitrogen gas, and then the generated nitrogen gas is transported to the second inert gas buffer tank 22 through a high-pressure and high-purity supply pipe for buffering and pressure stabilization.

[0050] In this embodiment, the inert gas generating device 1 outputs 0.17 bar low-pressure nitrogen and 8 bar high-pressure nitrogen through the nitrogen generator 7, and outputs dry air through the filter unit 6. The 0.17 bar low-pressure nitrogen output by the nitrogen generator 7 is transported to the cargo manifold area of ​​the chemical ship through the second air supply pipeline 15 to inertate the cargo hold, or the dry air output by the filter unit 6 is transported to the cargo manifold area of ​​the chemical ship through the second air supply pipeline 15 without passing through the nitrogen generator 7 to dry the cargo hold.

[0051] More specifically, a double-stop vent valve 16, a pressure vacuum protection device 17, an isolation valve 18 and a blind flange 19 are sequentially arranged on the second air supply pipeline 15 along the conveying path of the second air supply pipeline. After removing the blind flange 19, the connecting hose is connected to the cargo manifold to convey nitrogen into the cargo hold to inertate the cargo hold or convey dry air into the cargo hold to ventilate and dry the cargo hold. Through the pressure vacuum protection device 17, when the pressure in the pipeline is high, it is exhausted to the atmosphere, and when the pressure is low, air can be inhaled to supplement the pressure.

[0052] The 8 bar high-pressure nitrogen output by the nitrogen generator 7 , the 8 bar high-pressure nitrogen output by the high-pressure inert gas bottle group or the 8 bar high-pressure nitrogen output by the inert gas tank device 3 is transported through the first gas supply pipeline 20 .

[0053] The air dryer 8 of the inert gas generating device 1 outputs 8 bar dry air to provide 8 bar dry air to the equipment in the deck area through the deck miscellaneous air pipe 30, which can be used as driving power for the equipment on the deck and for deck cleaning.

[0054] After passing through the pressure regulating valve box 23, 8 bar nitrogen is output to the inert gas purge pipeline for purging the cargo pump / cargo pipeline to remove residual liquid cargo remaining in the pipeline or liquid cargo tank. The 8 bar nitrogen in the inert gas purge pipeline can be either high-purity nitrogen with a purity of ≥99.9% or low-purity nitrogen with a purity of ≥95% and ≤99.9%. The nitrogen concentration required for purging depends on the type of chemical liquid cargo carried; the pressure regulating valve box 23 outputs 0.17 bar low-pressure nitrogen to the inert gas supply pipeline.

[0055] It should be noted that the 0.17 bar nitrogen and 8 bar nitrogen output in this embodiment are merely commonly used nitrogen pressures and are not limitations of the present invention. The pressures of nitrogen output by the nitrogen generator 7, the pressure regulating valve box 23, and the liquid nitrogen evaporator 13 can be adjusted according to actual needs.

[0056] This embodiment also provides a chemical tanker, such as Figure 1 As shown, the above-mentioned inert gas system is arranged on the chemical tanker 31; the inert gas generating device 1 is arranged in the engine room 34 of the safe area of ​​the chemical tanker 31, the high-pressure inert gas bottle group 2 and the inert gas tank device 3 are arranged on the open deck 35 of the dangerous area of ​​the chemical tanker and are located in the bow direction of the cargo manifold area 32; the inert gas supply pipeline is connected to the ventilation tower 29 on the chemical tanker, the ventilation tower 29 is distributed on the open deck of the dangerous area of ​​the chemical tanker and is located on the left front side, right front side, left rear side and right rear side of the open deck; the ventilation tower 29 is connected to the cargo hold ventilation pipe of the cargo hold through a hose, and a stop check valve 29 with a quick connector is provided on the hose, and the cargo hold ventilation pipe delivers the inert gas to the top of the cargo hold to form a top air cushion.

[0057] For goods that do not require too high nitrogen purity, the inert gas generating device 1, the high-pressure inert gas bottle group 2 and the inert gas tank device 3 are backup for each other and can all supply nitrogen. For goods that require higher nitrogen purity, such as goods with a nitrogen purity requirement of ≥99.99%, the high-pressure inert gas bottle group 2 and the inert gas tank device 3 are backup for each other and can provide nitrogen with higher purity.

[0058] This embodiment is only a further explanation of the present invention, not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed, but as long as it is within the scope of the claims of the present invention, it will be protected by the patent law.

Claims

1. A chemical tanker inert gas system, characterized in that: include: Inert gas generating device, used to produce inert gas and provide dry air; High-pressure inert gas cylinder group, used to load pressurized gaseous inert gas; Inert gas tank device, used to carry liquid inert gas; A first gas supply pipeline, comprising a first inert gas buffer tank, a second inert gas buffer tank, and a pressure regulating valve box arranged along the first gas supply pipeline; The high-pressure inert gas cylinder group and the inert gas tank device are connected with a high-pressure and high-purity supply pipe, and the high-pressure inert gas cylinder group and the inert gas tank device respectively provide inert gas to the second inert gas buffer tank through the high-pressure and high-purity supply pipe; The inert gas generated by the inert gas generating device flows through the first inert gas buffer tank along the first gas supply pipeline and is then delivered to the pressure regulating valve box; the inert gas generated by the high-pressure inert gas bottle group and the inert gas tank device flows through the second inert gas buffer tank and is then delivered to the pressure regulating valve box along the first gas supply pipeline; An inert gas purge pipeline, used to connect the pressure regulating valve box to obtain inert gas from the first gas supply pipeline for purging the cargo pump and / or cargo pipeline; The inert gas supply pipeline is used to connect the pressure regulating valve box to obtain inert gas from the first gas supply pipeline to form an air cushion protection on the top of the cargo hold.

2. A chemical tanker inert gas system according to claim 1, characterized in that: The purity of the inert gas provided by the high-pressure inert gas cylinder group and the inert gas tank device is ≥99.99%, and the purity of the inert gas produced by the inert gas generating device is ≥95% and ≤99.9%.

3. The inert gas system for a chemical tanker according to claim 1, characterized in that: The inert gas generating device is also connected to a second gas supply pipeline, through which the inert gas generating device delivers inert gas to the cargo manifold area of ​​the chemical ship to inertate the cargo hold or delivers dry air to dry the cargo hold; the gas pressure intensity of the inert gas delivered by the second gas supply pipeline is lower than the gas pressure intensity of the inert gas delivered by the first gas supply pipeline.

4. The inert gas system for a chemical tanker according to claim 1, characterized in that: The inert gas generating device is also connected to a deck miscellaneous air pipe, and the inert gas generating device provides dry air to the deck area through the deck miscellaneous air pipe.

5. The inert gas system for a chemical tanker according to claim 1, characterized in that: The inert gas is nitrogen, and the inert gas generating device comprises an air compressor unit, an air buffer tank, a filter unit, an air dryer, and a nitrogen generator; the air compressor unit, the air buffer tank, and the filter unit are connected in sequence to generate dry air; the air compressor unit, the air buffer tank, the filter unit, and the nitrogen generator are connected in sequence to separate nitrogen from the air; the air compressor unit, the air buffer tank, and the air dryer are connected in sequence to generate dry air.

6. A chemical tanker inert gas system according to claim 5, characterized in that: The high-pressure inert gas cylinder group includes a high-pressure nitrogen cylinder, a gas supply main pipe, and a pressure reducing valve arranged on the gas supply main pipe. The high-pressure nitrogen cylinder is connected to a high-pressure and high-purity supply pipe through the gas supply main pipe; the gas supply main pipe is also connected to a high-pressure and high-purity supply sub-pipe after passing through the pressure reducing valve, and the high-purity supply sub-pipe is connected to the pressure regulating valve box.

7. The inert gas system for a chemical tanker according to claim 5, characterized in that: The inert gas tank device comprises a liquid nitrogen tank, a liquid nitrogen evaporator, and a liquid nitrogen filling manifold. The liquid nitrogen tank is used to store liquid nitrogen and provide liquid nitrogen to the liquid nitrogen evaporator. The liquid nitrogen filling manifold is used to replenish liquid nitrogen to the liquid nitrogen tank. The liquid nitrogen evaporator is used to convert the liquid nitrogen provided by the liquid nitrogen tank into nitrogen gas.

8. The inert gas system for a chemical tanker according to claim 3, characterized in that: The second gas supply pipeline includes a double-stop air-permeable valve, a pressure vacuum protection device, an isolation valve and a blind flange arranged along the conveying path of the second gas supply pipeline.

9. The inert gas system for a chemical tanker according to claim 1, characterized in that: The inert gas purge pipeline includes a purge pipeline and a stop check valve arranged on the purge pipeline; The inert gas supply pipeline comprises an air supply pipeline and a cut-off air-permeable valve arranged on the air supply pipeline.

10. A chemical tanker, characterized in that: An inert gas system as claimed in any one of claims 1 to 9 is arranged on the chemical tanker; the inert gas generating device is arranged in the engine room in the safe area of ​​the chemical tanker, the high-pressure inert gas bottle group and the inert gas tank device are arranged on the open deck in the dangerous area of ​​the chemical tanker and are located in the bow direction of the cargo manifold area; the inert gas supply pipeline is connected to the ventilation tower on the chemical tanker, and the ventilation tower is distributed on the open deck in the dangerous area of ​​the chemical tanker and is located on the left front side, right front side, left rear side and right rear side of the open deck; the ventilation tower is connected to the cargo hold ventilation pipe of the cargo hold through a hose, and the hose is provided with a stop check valve with a quick connector, and the cargo hold ventilation pipe delivers the inert gas to the top of the cargo hold to form a top air cushion.

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