Chemical tanker liquid cargo transfer system and method of transfer

Abstract

The present application relates to a kind of chemical tanker liquid cargo delivery system and its delivery method, including delivery pipe unit, delivery pipe unit includes the transverse pipe being arranged above deck and with multiple liquid cargo pipe, also including wharf liquid injection pipe, liquid injection communication pipe and multiple liquid injection branch pipe;Washing unit, washing unit includes the fresh water washing pipe line being communicated with transverse pipe and seawater ballast pipe line, fresh water washing pipe line has fresh water washing pump on, seawater ballast pipe line has seawater ballast pump on, fresh water washing pipe line and seawater ballast pipe line all have heater one on;Heating unit, heating unit includes multiple heaters two being arranged on multiple liquid injection branch pipe;Inert gas purging unit, inert gas purging unit includes the inert gas main pipe being communicated with transverse pipe.The present application has the following advantages: ensure liquid cargo delivery efficiency, improve the cleanliness and stability inside liquid cargo tank.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical liquid cargo ship, and particularly relates to a chemical ship liquid cargo delivery system. BACKGROUND

[0002] The chemical ship is also called liquid cargo ship, and is built or modified for carrying various toxic, flammable, volatile or corrosive chemical substances. The liquid chemical ship is mostly double-bottomed and double-sides, and the cargo hold is provided with partition and equipped with special liquid cargo pump and pipeline. The inner wall of the cargo hold and the pipeline are made of stainless steel or anticorrosive paint. The liquid cargo delivery system is the main system of the cargo hold of the chemical ship, and the main functions include discharging the liquid cargo in the cargo hold to the station or discharging the residual liquid cargo in the hold to the slop tank for treatment according to the need. To achieve the above functions, the pipeline connection in the deck and the shore area is mainly used.

[0003] The existing liquid cargo delivery system has the following technical defects: before the liquid cargo hold is delivered, the liquid cargo hold is mainly cleaned by using ballast seawater or fresh water. Since the chemical residual liquid has certain viscosity, if the cleaning is not thorough, the chemical residual liquid after the last delivery is adhered to the inner wall of the liquid cargo hold, and the liquid cargo is mixed and contaminated. In order to ensure the viscosity and delivery efficiency of the liquid cargo, the liquid cargo is usually heated. Generally, a heating coil is arranged in the liquid cargo hold. However, the heating coil occupies the internal volume of the liquid cargo hold, and is not conducive to the cleaning of the chemical residual liquid, and the technical problem of incomplete cleaning cannot be solved, thereby affecting the purity of the liquid cargo delivery. SUMMARY

[0004] The purpose of the present application is to overcome the above shortcomings, and provide a chemical ship liquid cargo delivery system and a delivery method, which can ensure the delivery efficiency of the liquid cargo and improve the cleanliness and stability of the liquid cargo hold.

[0005] The purpose of the present application is achieved by the following technical scheme: a chemical ship liquid cargo delivery system, comprising

[0006] A delivery pipe unit, the delivery pipe unit comprises a cross pipe arranged above the deck and a plurality of liquid cargo pipes, one end of the liquid cargo pipe is connected with the corresponding liquid cargo hold, the other end of the liquid cargo pipe is connected with the cross pipe, the plurality of liquid cargo pipes are connected with the cross pipe in common, one end of the cross pipe is connected with a delivery pipe, and the delivery system further comprises a wharf liquid injection pipe, a liquid injection communication pipe and a plurality of liquid injection branch pipes, the plurality of liquid injection branch pipes are sequentially connected with the plurality of liquid cargo holds, the extension direction of the cross pipe is consistent with the extension direction of the liquid injection communication pipe, the liquid injection branch pipe is provided with a control valve three, the liquid injection branch pipe is provided with a branch pipe connected with the liquid cargo pipe, and the branch pipe is provided with a control valve four.

[0007] A washing unit, the washing unit comprises a fresh water washing pipeline and a seawater ballast pipeline which are communicated with the cross pipe, the fresh water washing pipeline is provided with a fresh water washing pump, the seawater ballast pipeline is provided with a seawater ballast pump, and the fresh water washing pipeline and the seawater ballast pipeline are both provided with a heater one;

[0008] A heating unit, the heating unit comprises a plurality of heaters two which are arranged on a plurality of liquid injection branch pipes;

[0009] An inert gas purging unit, the inert gas purging unit comprises an inert gas main pipe which is communicated with the cross pipe.

[0010] Further improvement of the present application is that the inert gas main pipe is connected with two branch pipes, one branch pipe is a vapor gas discharge pipe, and the other branch pipe is an inert gas supply pipe, the inert gas supply pipe is provided with a control valve one, the vapor gas discharge pipe is provided with a pressure sensor and a control valve two, the pressure sensor is arranged at a front position of the control valve two, the end of the inert gas supply pipe is connected with an inert gas source, and the end of the vapor gas discharge pipe is connected with an inert gas release cover.

[0011] Further improvement of the present application is that each liquid cargo tank is provided with a liquid cargo temperature sensor and an inert gas pressure sensor.

[0012] Further improvement of the present application is that the heater two arranged on the liquid injection branch pipe is arranged on the outer side of the deck.

[0013] Further improvement of the present application is that the liquid cargo tank is provided with an oil suction well and a liquid cargo pump, one end of a liquid cargo pipe penetrates the deck and is arranged in the oil suction well of the liquid cargo tank, the liquid cargo pump is connected with the liquid cargo pipe and arranged in the oil suction well, and the liquid cargo pipe arranged on the outer wall of the liquid cargo tank is provided with a plurality of longitudinally distributed support rings which fix the liquid cargo pipe and the inner wall of the liquid cargo tank.

[0014] Further improvement of the present application is that the oil suction well is recessed on the inner bottom of the liquid cargo tank.

[0015] A delivery method of a liquid cargo delivery system of a chemical tanker, and the specific steps comprise,

[0016] S1, washing, the fresh water washing pump and the seawater ballast pump are opened, fresh water is heated by the heater one under the action of the fresh water washing pump, and seawater is heated by the heater one under the action of the seawater ballast pump, and then the fresh water and the seawater flow into the cross pipe, and then the fresh water and the seawater flow into the liquid cargo tank through the liquid cargo pipe for washing;

[0017] S2, inert gas purging, the control valve two is closed, the control valve one is opened, the inert gas supply pipe purges the plurality of liquid cargo pipes, and the inert gas flows into the liquid cargo tank through the inert gas supply pipe, the cross pipe and the liquid cargo pipe, so as to reduce the oxygen content in the liquid cargo tank, inert the empty liquid cargo tank, and reduce the oxygen content below the lower limit of explosion;

[0018] S3. Heated transport: When liquid cargo is transported from the dock to the cargo tank, the liquid cargo pump is turned off and control valve three is opened. The liquid cargo on the dock flows sequentially through the dock injection pipe, the injection connecting pipe and the injection branch pipe to the corresponding cargo tank. The heater two on the injection branch pipe quickly heats the passing liquid cargo, thereby realizing the transport of liquid cargo on the dock. When the liquid cargo in the cargo tank is transported outward, control valve three is turned off and the liquid cargo pump is turned on. The liquid cargo in the cargo tank flows sequentially through the cargo pipe and the cross pipe to the outlet pipe.

[0019] A further improvement of the present invention is that, in step S3, when the liquid cargo in the liquid cargo tank is not circulating, the temperature sensor in the liquid cargo tank detects the temperature of the liquid cargo in real time. If the temperature of the liquid cargo is lower than the predetermined value set by the system, control valve three, control valve four and the liquid cargo pump are started. The liquid cargo in the liquid cargo tank flows into the liquid cargo pipe and the liquid injection pipe under the pressure of the liquid cargo pump. Under the heating action of the heater two in the liquid injection pipe, the liquid cargo is circulated and heated until the liquid cargo reaches the predetermined value set by the system.

[0020] A further improvement of the present invention is as follows: After the liquid cargo in the liquid cargo tank has been transported outward, if the pressure value detected by the pressure sensor on the vapor discharge pipe reaches the upper threshold set by the system, it indicates that there is a lot of vapor in the liquid cargo tank and the cross pipe. At this time, the control valve two on the vapor discharge pipe opens and the control valve one on the inert gas supply pipe closes, so that the vapor generated in the liquid cargo tank is discharged and collected outward along with the vapor discharge pipe. When the pressure value detected by the pressure sensor reaches the lower threshold set by the system, it indicates that there is a little vapor in the liquid cargo tank and the cross pipe. At this time, the control valve two on the vapor discharge pipe closes and the control valve one on the inert gas supply pipe opens to replenish inert gas into the liquid cargo tank. When the inert gas pressure detected by the inert gas pressure sensor in the liquid cargo tank reaches the predetermined value set by the system, the control valve one closes.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. This invention places the heating unit on the injection pipe above the deck, eliminating the need for heating coils inside the cargo tank. This prevents cargo from accumulating around the heating coils and affecting the cleaning efficiency of residual cargo, thus reducing cargo residue and facilitating rapid cleaning. Secondly, this invention not only cleans the cargo tank before transport but also purges it with inert gas to reduce the oxygen content, inertizing the empty cargo tank and lowering the oxygen content below the lower explosive limit. This provides a safety guarantee for cargo transport. After cargo transport is complete, a negative pressure state is formed inside the cargo tank. Inert gas is then added to maintain the cleanliness and stability of the cargo tank, improving the cleaning efficiency before and after cargo transport and ensuring safe cargo transport.

[0023] 2. The heaters of the heating unit are installed in multiple injection pipes to rapidly heat the liquid cargo at the dock before it is transported to the cargo tank. This increases the temperature of the liquid cargo to reduce its viscosity, decreases transport friction loss, ensures the fluidity of the liquid cargo in the cargo tank, and prevents pipeline blockage. At the same time, when the liquid cargo is not being transported, it remains at a constant temperature. Through the cooperation of the injection pipes, the cargo pipes, and the cargo pump, the liquid cargo is circulated and heated, providing a basis for subsequent transport. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a chemical tanker liquid cargo transportation system according to the present invention.

[0025] Figure 2 for Figure 1 A schematic diagram showing the connection between a single liquid cargo tank and the cross pipe and liquid injection connecting pipe.

[0026] Numbering on the map:

[0027] 1-Transportation pipe unit, 2-Washing tank unit, 3-Heating unit, 4-Inert gas filling unit;

[0028] 11-Crossing pipe, 12-Liquid cargo pipe, 13-Liquid cargo tank, 14-Discharge pipe, 15-Dock injection pipe, 16-Injection connecting pipe, 17-Injection branch pipe, 18-Control valve three, 19-Branch pipe, 110-Control valve four; 131-Suction well, 132-Liquid cargo pump, 133-Support ring;

[0029] 21-Freshwater tank washing pipeline, 22-Seawater ballast pipeline, 23-Freshwater tank washing pump, 24-Seawater ballast pump, 25-Heater 1;

[0030] 31-Heater II;

[0031] 41-Inert gas main pipe, 42-Evaporator discharge pipe, 43-Inert gas supply pipe, 44-Control valve one, 45-Pressure sensor, 46-Control valve two. Detailed Implementation

[0032] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments and accompanying drawings. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0033] In the description of this invention, it should be understood that the terms indicating orientation or positional relationship, such as those based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the structure or unit referred to must have a specific orientation, and therefore should not be construed as a limitation of this invention.

[0034] In this invention, unless otherwise explicitly specified and limited, terms such as “connection,” “provided with,” and “have” should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can be described as a mechanical connection, a direct connection, or a connection through an intermediate medium. Those skilled in the art can understand the basic meaning of the above terms in this invention according to the specific circumstances.

[0035] A chemical tanker liquid cargo transfer system, with reference to Figure 1 , Figure 2 ,include

[0036] The delivery pipe unit 1 includes a transverse pipe 11 installed above the deck and multiple cargo pipes 12. One end of each cargo pipe 12 is connected to a corresponding cargo tank 13, and the other end of each cargo pipe 12 is connected to the transverse pipe 11. The multiple cargo pipes 12 are connected to the transverse pipe 11. One end of the transverse pipe 11 is connected to the outlet pipe 14. The unit also includes a dock injection pipe 15, an injection connection pipe 16, and multiple injection branch pipes 17. The multiple injection branch pipes 17 are connected to multiple cargo tanks 13 in sequence. The extension direction of the transverse pipe 11 is the same as the extension direction of the injection connection pipe 16. The injection branch pipe 17 has a control valve 18. The injection branch pipe 17 has a branch pipe 19 connected to the cargo pipe 12. The branch pipe 19 has a control valve 110.

[0037] Tank washing unit 2 includes a freshwater tank washing pipeline 21 connected to the cross pipe 11 and a seawater ballast pipeline 22. The freshwater tank washing pipeline 21 is equipped with a freshwater tank washing pump 23, and the seawater ballast pipeline 22 is equipped with a seawater ballast pump 24. Both the freshwater tank washing pipeline 21 and the seawater ballast pipeline 22 are equipped with heaters 25.

[0038] Heating unit 3, which includes multiple heaters 31 disposed on multiple injection pipes 17;

[0039] The inert gas purging unit 4 includes an inert gas main pipe 41 connected to the transverse pipe 11.

[0040] This invention places the heating unit 3 on the liquid injection manifold 17 above the deck, eliminating the need for heating coils inside the cargo tank 13. This prevents cargo from accumulating around the heating coils and affecting the cleaning efficiency of residual cargo, thus reducing cargo residue and facilitating rapid cleaning. Furthermore, this invention not only cleans the cargo tank before transport using the washing unit 2 but also purges the cargo tank 13 with inert gas to reduce the oxygen content inside, inertizing the empty cargo tank and lowering the oxygen content below the lower explosive limit. This provides a safety guarantee for cargo transport. After cargo transport is completed, a negative pressure state is formed inside the cargo tank 13. Inert gas is then added to maintain the cleanliness and stability of the cargo tank, improving the cleaning efficiency before and after cargo transport and ensuring safe cargo transport.

[0041] Furthermore, the main inert gas pipe 41 is connected to two branch pipes: one branch pipe is the evaporation gas discharge pipe 42, and the other branch pipe is the inert gas supply pipe 43. The inert gas supply pipe 43 is equipped with a control valve 44, and the evaporation gas discharge pipe 42 is equipped with a pressure sensor 45 and a control valve 46. The pressure sensor 45 is located at the leading edge of the control valve 46. The end of the inert gas supply pipe 43 is connected to an inert gas source, and the end of the evaporation gas discharge pipe 42 is connected to an inert gas release cover.

[0042] Furthermore, the liquid cargo tank 13 is equipped with a liquid cargo temperature sensor and an inert gas pressure sensor.

[0043] Furthermore, heater 2 31 on injection manifold 17 is located on the outside of the deck.

[0044] Furthermore, the cargo tank 13 has an oil suction well 131 and a cargo pump 132. One end of the cargo pipe 12 penetrates the deck and is placed in the oil suction well 131 of the cargo tank 13. The cargo pump 132 is connected to the cargo pipe 12 and is placed in the oil suction well 131. The cargo pipe 12 has multiple longitudinally distributed support rings 133 on the outer wall inside the cargo tank 13. The support rings 133 fix the cargo pipe 12 to the inner wall of the cargo tank 13.

[0045] The support ring 133 between the inner wall of the liquid cargo tank 13 and the liquid cargo pipe 12 serves to fix the liquid cargo pipe 12 and the liquid cargo pump 132 in the tank, so that they are not subjected to lateral shear force. The arrangement of the support ring 133 can be adjusted up and down according to the actual situation without affecting the normal use of the liquid cargo pipe 12 and the liquid cargo pump 132.

[0046] Furthermore, the suction well 131 is recessed into the bottom of the inner side of the liquid cargo tank 13, so that the suction port of the liquid cargo pump 132 is located in the suction well 131 at the bottom of the liquid cargo tank 13, ensuring that the system can efficiently suction and transport liquid, clean the tank, etc.

[0047] A method for conveying liquid cargo in a chemical tanker, comprising the following steps:

[0048] S1, tank washing: Fresh water tank washing pump 23 and seawater ballast pump 24 are turned on. Fresh water is heated by heater 25 under the action of fresh water tank washing pump 23 and seawater is heated by seawater ballast pump 24 and flows together into cross pipe 11. Fresh water and seawater pass through cargo pipe 12 to cargo tank 13 for tank washing.

[0049] S2. Inert gas purging: Control valve 2 46 is closed, control valve 1 44 is opened, and inert gas supply pipe 43 purges multiple liquid cargo pipes 12 with inert gas. The inert gas passes through cross pipe 11 and liquid cargo pipe 12 in sequence from inert gas supply pipe 43 to liquid cargo tank 13, thereby reducing the oxygen content in liquid cargo tank 13, making the empty liquid cargo tank inert, and reducing the oxygen content to below the lower explosive limit.

[0050] S3. Heating and conveying: When liquid cargo on the dock is conveyed into the liquid cargo tank 13, the liquid cargo pump 132 is closed and the control valve 18 is opened. The liquid cargo on the dock flows sequentially through the dock injection pipe 15, the injection connecting pipe 16 and the injection branch pipe 17 into the corresponding liquid cargo tank 13. The heater 31 on the injection branch pipe 17 quickly heats the passing liquid cargo, thereby realizing the conveying of liquid cargo on the dock. When the liquid cargo in the liquid cargo tank 13 is conveyed outward, the control valve 18 is closed and the liquid cargo pump 132 is opened. The liquid cargo in the liquid cargo tank 13 flows sequentially through the liquid cargo pipe 12 and the cross pipe 11 into the outlet pipe 14.

[0051] Based on this embodiment, in step S3, when the liquid cargo in the liquid cargo tank 13 is not circulating, the temperature sensor in the liquid cargo tank 13 detects the temperature of the liquid cargo in real time. If the temperature of the liquid cargo is lower than the predetermined value set by the system, control valve three 18, control valve four 110 and liquid cargo pump 132 are started. The liquid cargo in the liquid cargo tank 13 flows into the liquid cargo pipe 12 and the liquid injection branch pipe 17 under the pumping pressure of the liquid cargo pump 132. Under the heating action of the heater two 31 in the liquid injection branch pipe 17, the liquid cargo is circulated and heated until the liquid cargo reaches the predetermined value set by the system.

[0052] In this invention, the heater 31 of the heating unit 3 is installed in multiple liquid injection pipes 17 to rapidly heat the liquid cargo at the dock before it is transported to the liquid cargo tank 13, thereby increasing the temperature of the liquid cargo to reduce its viscosity, reduce transport friction loss, ensure the fluidity of the liquid cargo in the liquid cargo tank 13, and prevent pipeline blockage. At the same time, when the liquid cargo is not being transported, the liquid cargo is kept at a constant temperature. Through the cooperation of the liquid injection pipes 17, the liquid cargo pipes 12, and the liquid cargo pump 132, the liquid cargo is circulated and heated, providing a basis for subsequent transport.

[0053] Based on this embodiment, after the liquid cargo in the liquid cargo tank 13 has been transported out, if the pressure value detected by the pressure sensor 45 on the vapor discharge pipe 42 reaches the upper threshold set by the system, it indicates that there is a lot of vapor in the liquid cargo tank 13 and the cross pipe 11. At this time, the control valve 2 46 on the vapor discharge pipe 42 opens and the control valve 1 44 on the inert gas supply pipe 43 closes, so that the vapor generated in the liquid cargo tank 13 is discharged and collected outward along with the vapor discharge pipe 42. When the pressure value detected by the pressure sensor reaches the lower threshold set by the system, it indicates that there is a little vapor in the liquid cargo tank 13 and the cross pipe 11. At this time, the control valve 2 46 on the vapor discharge pipe 42 closes and the control valve 1 44 on the inert gas supply pipe 43 opens to replenish the inert gas in the liquid cargo tank 13. When the inert gas pressure detected by the inert gas pressure sensor in the liquid cargo tank 13 reaches the predetermined value set by the system, the control valve 1 44 closes.

[0054] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A liquid cargo transfer system for a chemical tanker, characterized in that: include The delivery pipe unit (1) includes a transverse pipe (11) installed above the deck and multiple cargo pipes (12). One end of each cargo pipe (12) is connected to a corresponding cargo tank (13), and the other end is connected to the transverse pipe (11). The multiple cargo pipes (12) are connected to the transverse pipe (11). One end of the transverse pipe (11) is connected to an outlet pipe (14). The unit also includes a dock injection pipe (15) and an injection... The liquid connecting pipe (16) and multiple liquid injection branch pipes (17) are connected in sequence to multiple liquid cargo tanks (13). The extension direction of the cross pipe (11) is consistent with the extension direction of the liquid connecting pipe (16). The liquid injection branch pipe (17) has a control valve three (18). The liquid injection branch pipe (17) has a branch pipe (19) connected to the liquid cargo pipe (12). The branch pipe (19) has a control valve four (110). The tank washing unit (2) includes a freshwater tank washing pipeline (21) connected to the cross pipe (11) and a seawater ballast pipeline (22). The freshwater tank washing pipeline (21) is equipped with a freshwater tank washing pump (23), and the seawater ballast pipeline (22) is equipped with a seawater ballast pump (24). Both the freshwater tank washing pipeline (21) and the seawater ballast pipeline (22) are equipped with a heater (25). Heating unit (3), the heating unit (3) includes multiple heaters (31) disposed on multiple injection manifolds (17); The inert gas purging unit (4) includes an inert gas main pipe (41) connected to the cross pipe (11).

2. The chemical tanker liquid cargo transfer system according to claim 1, characterized in that: The main inert gas pipe (41) is connected to two branch pipes. One branch pipe is the evaporation gas discharge pipe (42), and the other branch pipe is the inert gas supply pipe (43). The inert gas supply pipe (43) has a control valve one (44), and the evaporation gas discharge pipe (42) has a pressure sensor (45) and a control valve two (46). The pressure sensor (45) is located at the leading edge of the control valve two (46). The end of the inert gas supply pipe (43) is connected to an inert gas source, and the end of the evaporation gas discharge pipe (42) is connected to an inert gas release cover.

3. The chemical tanker liquid cargo transfer system according to claim 2, characterized in that: Each of the said liquid cargo tanks (13) is equipped with a liquid cargo temperature sensor and an inert gas pressure sensor.

4. The chemical tanker liquid cargo transfer system according to claim 3, characterized in that: The heater 2 (31) on the injection manifold (17) is located on the outside of the deck.

5. The chemical tanker liquid cargo transfer system according to claim 4, characterized in that: The cargo tank (13) has an oil suction well (131) and a cargo pump (132). One end of the cargo pipe (12) penetrates the deck and is placed in the oil suction well (131) of the cargo tank (13). The cargo pump (132) is connected to the cargo pipe (12) and is placed in the oil suction well (131). The cargo pipe (12) is placed on the outer wall of the cargo tank (13) and has multiple longitudinally distributed support rings (133). The support rings (133) fix the cargo pipe (12) to the inner wall of the cargo tank (13).

6. The chemical tanker liquid cargo transfer system according to claim 5, characterized in that: The oil suction well (131) is recessed at the bottom of the inner side of the liquid cargo tank (13).

7. A method for conveying liquid cargo using the chemical tanker liquid cargo conveying system of claim 6, characterized in that: The specific steps include, S1, tank washing: the fresh water tank washing pump (23) and the seawater ballast pump (24) are turned on. The fresh water is heated by the heater (25) under the action of the fresh water tank washing pump (23) and the seawater is heated by the seawater ballast pump (24) and flows together into the cross pipe (11). The fresh water and seawater pass through the cargo pipe (12) in sequence to the cargo tank (13) for tank washing. S2. Inert gas purging: Control valve 2 (46) is closed, control valve 1 (44) is opened, and inert gas supply pipe (43) purges multiple liquid cargo pipes (12) with inert gas. The inert gas passes through the cross pipe (11) and liquid cargo pipe (12) in sequence from the inert gas supply pipe (43) to the liquid cargo tank (13), thereby reducing the oxygen content in the liquid cargo tank (13), making the empty liquid cargo tank inert, and reducing the oxygen content to below the lower explosive limit. S3. Heating and conveying: When the liquid cargo on the dock is conveyed into the liquid cargo tank (13), the liquid cargo pump (132) is closed and the control valve three (18) is opened. The liquid cargo on the dock flows into the corresponding liquid cargo tank (13) through the dock injection pipe (15), the injection connecting pipe (16) and the injection branch pipe (17) in sequence. The heater two (31) on the injection branch pipe (17) heats the liquid cargo that passes through quickly, thereby realizing the conveying of the liquid cargo on the dock. When the liquid cargo in the liquid cargo tank (13) is conveyed outward, the control valve three (18) is closed and the liquid cargo pump (132) is opened. The liquid cargo in the liquid cargo tank (13) flows into the outlet pipe (14) through the liquid cargo pipe (12) and the cross pipe (11) in sequence.

8. The method for conveying liquid cargo in a chemical tanker according to claim 7, characterized in that: In step S3, when the liquid cargo in the liquid cargo tank (13) is not circulating, the temperature sensor in the liquid cargo tank (13) detects the temperature of the liquid cargo in real time. If the temperature of the liquid cargo is lower than the predetermined value set by the system, the control valve three (18), the control valve four (110) and the liquid cargo pump (132) are started. The liquid cargo in the liquid cargo tank (13) flows into the liquid cargo pipe (12) and the liquid injection branch pipe (17) under the pumping pressure of the liquid cargo pump (132). The liquid cargo is circulated and heated under the heating action of the heater two (31) of the liquid injection branch pipe (17) until the liquid cargo reaches the predetermined value set by the system.

9. A method for conveying liquid cargo in a chemical tanker according to claim 7 or 8, characterized in that: After the liquid cargo in the liquid cargo tank (13) has been transported out, if the pressure value detected by the pressure sensor (45) on the vapor discharge pipe (42) reaches the upper threshold set by the system, it indicates that there is a lot of vapor in the liquid cargo tank (13) and the cross pipe (11). At this time, the control valve two (46) on the vapor discharge pipe (42) opens and the control valve one (44) on the inert gas supply pipe (43) closes, so that the vapor generated in the liquid cargo tank (13) is discharged outward along with the vapor discharge pipe (42). When the pressure value detected by the pressure sensor reaches the lower threshold set by the system, it indicates that there is less evaporation gas in the liquid cargo tank (13) and the cross pipe (11). At this time, the control valve 2 (46) on the evaporation gas discharge pipe (42) is closed, and the control valve 1 (44) on the inert gas supply pipe (43) is opened to replenish inert gas into the liquid cargo tank (13). When the inert gas pressure detected by the inert gas pressure sensor in the liquid cargo tank (13) reaches the predetermined value set by the system, the control valve 1 (44) is closed.

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