CN118067423A

CN118067423A - Gas combination test system and method for gas ship

Info

Publication number: CN118067423A
Application number: CN202410090456.5A
Authority: CN
Inventors: 董三国; 贺隆坤; 王哲; 张成友
Original assignee: Jiangnan Shipyard Group Co Ltd
Current assignee: Jiangnan Shipyard Group Co Ltd
Priority date: 2024-01-23
Filing date: 2024-01-23
Publication date: 2024-05-24

Abstract

The application provides a gas combination test system and a gas combination test method for a gas ship. The system comprises a plurality of cargo tanks, a tank car, a filling pipe, a condensing pipe, a re-liquefying mechanism and a main exhaust pipe. The re-liquefying mechanism comprises a liquefying connecting pipe and a re-liquefying part, the liquefying connecting pipe is used for discharging the goods vapor in the corresponding liquid cargo tank, and the re-liquefying part is used for re-liquefying the goods vapor into liquid gas; the liquefied gas is discharged into other liquid cargo tanks through a liquefied connecting pipe for cooling; the main exhaust pipe is connected between two adjacent cargo tanks so that a plurality of cargo tanks are connected in series, and the main exhaust pipe is used for conveying cargo vapor generated in the cargo tanks to other cargo tanks for nitrogen replacement. By changing the serial-parallel connection mode among liquid cargo tanks in different operation stages, cargo vapor generated in the processes of front tank replacement, cold tank and filling is fully utilized to replace and cool the rear tank, so that the cargo vapor is efficiently utilized, and meanwhile, the air test time is saved.

Description

Gas combination test system and method for gas ship

Technical Field

The application relates to the technical field of gas tests of gas ships, in particular to a gas combination test system and method of a gas ship.

Background

Before a gas ship such as an LPG (liquefiedpetroleumgas, abbreviated as LPG) ship is delivered to a shipside, a gas test is required to be performed to verify functions and safety of a liquid cargo treatment and fuel supply system, auxiliary key equipment and the like, so that the gas test is a final checkpoint for ensuring smooth delivery of the gas ship, and is one of links with highest dangerous grade and highest cost in the construction process of the gas ship.

The gas test flow before sea test mainly comprises liquid cargo tank drying and inerting, replacement, cold cabin, filling and the like, and has the characteristics of low temperature, easy gasification, easy explosion, multiple cabins, small cabin pressure operation range and the like, so the gas test process is complex, high in danger, long in wharf period, high in cost and environment-friendly due to the fact that a large amount of LPG cargoes are consumed, and the cargo steam is discharged.

At present, a plurality of tanks are connected in parallel at the same time in a conventional gas test scheme, each cargo tank needs to be subjected to replacement, cold tank and filling operation, all tanks are often required to be replaced and cooled by low-temperature liquefied gas cargoes at a wharf, and a large amount of cargo steam is generated in the replacement, cold tank and filling process of each tank and can be only processed or burned by returning to a shore station.

In view of the foregoing, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.

Disclosure of Invention

The embodiment of the application aims to provide a gas combination test system and a gas combination test method for a gas ship, which can change the serial-parallel connection mode among liquid cargo tanks in different operation stages, fully utilize cargo vapor generated in the processes of front tank replacement, cold tank and filling to replace and cool a rear tank, realize the efficient utilization of the cargo vapor, and save gas test time.

In a first aspect, there is provided a gas ship gas combination test system comprising:

The plurality of cargo tanks at least comprise a first cargo tank, a second cargo tank, a third cargo tank and a fourth cargo tank;

The tank car is used for containing low-temperature liquefied gas;

the filling pipe is connected between the tank wagon and the fourth cargo tank, extends to the bottom of the fourth cargo tank and is used for filling the fourth cargo tank;

The condensing pipe comprises a fourth condensing pipe connected between the tank wagon and the fourth cargo tank, the fourth condensing pipe is connected with the filling pipe in parallel, and the fourth condensing pipe is used for spraying and cooling the fourth cargo tank;

the re-liquefying mechanism comprises a liquefying connecting pipe and a re-liquefying part, the liquefying connecting pipe is used for discharging the cargo vapor in the corresponding liquid cargo tank, and the re-liquefying part is used for re-liquefying the cargo vapor into liquid gas; the liquefied gas is discharged into other liquid cargo tanks through the liquefied connecting pipe for cooling;

The main exhaust pipe is connected between two adjacent cargo tanks, one end of the main exhaust pipe is an air inlet, the other end of the main exhaust pipe is an air outlet, the air inlet is connected to the top of the cargo tanks, and the air outlet extends into the bottom of the adjacent cargo tanks so that a plurality of cargo tanks are connected in series, and the main exhaust pipe is used for conveying cargo steam generated in the cargo tanks to other cargo tanks for nitrogen replacement.

In one embodiment, the pipeline where the reliquefaction part is located is a liquefaction connecting main pipe;

The first liquefaction connecting pipe is connected with the first cargo tank, the second liquefaction connecting pipe is connected with the second cargo tank, the third liquefaction connecting pipe is connected with the third cargo tank, and the fourth liquefaction connecting pipe is connected with the fourth cargo tank;

The first liquefaction connecting pipe, the second liquefaction connecting pipe, the third liquefaction connecting pipe and the fourth liquefaction connecting pipe are connected in parallel and are connected with the liquefaction connecting main pipe.

In one embodiment, the cargo tank further comprises a secondary exhaust pipe connected to the top of the cargo tank for conveying cargo vapor in the corresponding cargo tank;

The auxiliary exhaust pipe at least comprises an auxiliary exhaust main pipe, a first auxiliary exhaust pipe arranged at the top of the first liquid cargo tank, a second auxiliary exhaust pipe arranged at the top of the second liquid cargo tank, a third auxiliary exhaust pipe arranged at the top of the third liquid cargo tank and a fourth auxiliary exhaust pipe arranged at the top of the fourth liquid cargo tank;

the first auxiliary exhaust pipe, the second auxiliary exhaust pipe, the third auxiliary exhaust pipe and the fourth auxiliary exhaust pipe are connected in parallel and are connected to the auxiliary exhaust main pipe.

In one embodiment, the fourth liquefaction connection pipe and the fourth auxiliary exhaust pipe are the same pipeline; the liquefaction connecting main pipe is connected with the auxiliary exhaust main pipe in parallel.

In one embodiment, the main exhaust pipe includes at least a first main exhaust pipe, a second main exhaust pipe, a third main exhaust pipe, and a fourth main exhaust pipe, wherein the fourth main exhaust pipe is used for connecting a fourth cargo tank and a third cargo tank, the third main exhaust pipe is used for connecting the third cargo tank and a second cargo tank, the second main exhaust pipe is used for connecting the second cargo tank and the first cargo tank, and the first main exhaust pipe is connected to the top of the first cargo tank and extends upwards.

In one embodiment, the system further comprises a flare stack connected to the top of the first cargo tank via a first main exhaust pipe, the flare stack being configured to discharge tail gases such as nitrogen and incinerate cargo vapors.

In one embodiment, a connecting pipe is provided before the third auxiliary exhaust pipe merges into the auxiliary exhaust manifold, one end of the connecting pipe is connected with the third auxiliary exhaust pipe, the other end of the connecting pipe is connected with the third main exhaust pipe, and the connecting pipe is used for discharging cargo vapor in the third liquid cargo tank to the second liquid cargo tank to continue nitrogen replacement.

According to a second aspect of the present application, there is also provided a gas ship gas combination test method, for completing a gas combination test of a gas ship by the gas combination test system of a gas ship provided in the first aspect, comprising the steps of:

S1, injecting gas-phase cargoes into a tank wagon to replace nitrogen in a fourth liquid cargo compartment, and using cargo steam generated in the fourth liquid cargo compartment to replace nitrogen in other liquid cargo compartments;

S2, simultaneously connecting the fourth cargo tank and the third cargo tank in parallel with the cold tanks; the fourth liquid cargo tank is cooled by spraying low-temperature liquefied gas in a tank car of a wharf, and the third liquid cargo tank is cooled after the cargo vapor generated in the fourth liquid cargo tank is re-liquefied;

S3, utilizing cargo vapor generated in the third liquid cargo tank, discharging the cargo vapor to the second liquid cargo tank and the first liquid cargo tank through a main exhaust pipe to replace nitrogen, and discharging the nitrogen to a torch through a first main exhaust pipe at the top of the first liquid cargo tank;

s4, after the fourth cargo tank and the third cargo tank finish the cold tanks, filling the fourth cargo tank;

S5, after filling of the fourth cargo tank is completed, the ship leaves the wharf and goes to a preset offshore area to perform sea test; and in the sailing process, cargo vapor in the fourth cargo tank, the third cargo tank, the second cargo tank and the first cargo tank is extracted through the re-liquefying mechanism to control the tank pressure, and the cargo vapor is re-liquefied through the re-liquefying mechanism and then cools the first cargo tank.

In one embodiment, in step S2, the fourth cargo tank and the third cargo tank are connected in parallel with the cold tanks at the same time; the fourth cargo tank is cooled by spraying low-temperature liquefied gas in a tank car of the wharf, and the third cargo tank is cooled by a re-liquefying mechanism.

In an embodiment, in step S4, the cargo vapors in the fourth cargo tank and the third cargo tank are pumped by the re-liquefying mechanism and liquefied into liquids, and then injected into the second cargo tank through the second liquefying connection pipe, the second cargo tank is spray cooled, the cargo vapors generated by spray cooling of the second cargo tank are injected into the first cargo tank through the second main exhaust pipe, nitrogen in the first cargo tank is replaced, and then the nitrogen is discharged to the flare tower through the first main exhaust pipe.

Compared with the prior art, the application has the beneficial effects that:

According to the technical scheme, the cargo vapor generated in the front cabin replacement, cold cabin and filling processes is fully utilized to replace and cool the rear cabin by changing the serial-parallel connection mode among the liquid cargo cabins in different operation stages, so that the cargo vapor is efficiently utilized, and meanwhile, the air test time is saved. The replacement of a plurality of cargo tanks can be satisfied by only introducing gas cargo into one cargo tank; through the arrangement of the reliquefaction mechanism, a plurality of cabins are connected with the cold cabins in parallel in the cold cabin stage of the fourth cargo tank; and the parallel operation of filling, cooling and replacement is realized in the filling stage of the fourth cargo tank. The application realizes the maximum utilization of the cargo steam, saves a large amount of cargoes in the gas test, prevents the cargo steam from being discharged to the atmosphere, avoids polluting the environment, greatly saves the gas test time and improves the economy of the gas test.

Drawings

Fig. 1 is a schematic structural view of a gas combination test system of a gas ship according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of step S1 in the gas combination test system of the gas ship according to the embodiment of the present invention.

Fig. 3 is a schematic diagram of step S2 and step S3 in the gas combination test system of the gas ship according to the embodiment of the present invention.

Fig. 4 is a schematic diagram of step S4 in the gas combination test system of the gas ship according to the embodiment of the present invention.

Fig. 5 is a schematic diagram of step S5 in the gas combination test system of the gas ship according to the embodiment of the present invention.

Fig. 6 is a flow chart of a gas combination test method of a gas ship according to an embodiment of the present invention.

Wherein reference numerals are as follows:

1. A tank car; 2. a filling pipe; 3. a condensing tube; 4. a gasifier/heater; 5. a reliquefaction unit; 6. a flare stack; CT1, a first cargo tank; CT2, a second cargo tank; CT3, a third cargo tank; CT4, a fourth cargo tank; 7. liquefying and connecting a main pipe; 71. a first liquefaction connection pipe; 72. a second liquefaction connection pipe; 73. a third liquefaction connection pipe; 74. a fourth liquefaction connection tube; 8. a secondary exhaust manifold; 81. a first sub-exhaust pipe; 82. a second auxiliary exhaust pipe; 83. a third auxiliary exhaust pipe; 84. a fourth sub-exhaust pipe; 91. a first main exhaust pipe; 92. a second main exhaust pipe; 93. a third main exhaust pipe; 94. a fourth main exhaust pipe; 10. and (5) connecting pipes.

Detailed Description

The following describes the embodiments of the present invention in further detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and are not intended to be limiting.

In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

Furthermore, in the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

According to a first aspect of the present application, referring to fig. 1, there is provided a gas combination test system of a gas ship, comprising:

The liquid cargo tanks are used for storing and transporting low-temperature liquefied gas; the system at least comprises a first cargo tank CT1, a second cargo tank CT2, a third cargo tank CT3 and a fourth cargo tank CT4.

Tank car 1 for holding cryogenic liquefied gas.

In this embodiment, the low-temperature liquefied gas is LPG at a temperature of-35 ℃ to-196 ℃.

The filling pipe 2 is connected between the tank car 1 and the fourth cargo tank CT4, the filling pipe 2 extends to the bottom of the fourth cargo tank CT4, and the filling pipe 2 is used for filling the fourth cargo tank CT 4.

The filling pipe 2 is provided with a vaporizing/heating device 4, and the vaporizing/heating device 4 is used for heating the low-temperature liquefied gas supplied by the tank car 1 into normal-temperature gas-phase goods and then injecting the normal-temperature gas-phase goods into the fourth cargo tank CT 4. The temperature of the normal temperature gas phase cargo is 10-30 ℃.

The filler pipe 2 is a two-way pipe, and the low-temperature high-density vapor gas can be discharged from the bottom of the cargo tank through the filler pipe 2.

A condensation pipe 3, comprising a fourth condensation pipe 3 connected between the tank car 1 and the fourth cargo tank CT4, wherein the fourth condensation pipe 3 is arranged in parallel with the filling pipe 2, and the fourth condensation pipe 3 is connected to the top of the fourth cargo tank CT 4; the joint of the fourth condenser pipe 3 and the fourth cargo tank CT4 is provided with a spray head, and the spray head is used for spraying and cooling the fourth cargo tank CT 4.

The re-liquefying mechanism comprises a liquefying connecting pipe and a re-liquefying part 5, wherein the liquefying connecting pipe is used for discharging the cargo vapor in the corresponding liquid cargo tank, and the re-liquefying part 5 is used for re-liquefying the cargo vapor into liquid gas; the liquefied gas is discharged into other liquid cargo tanks through the liquefied connecting pipe for cooling; the pipeline where the reliquefaction part 5 is located is a liquefaction connecting main pipe 7.

Specifically, the liquefaction connection pipes include a first liquefaction connection pipe 71, a second liquefaction connection pipe 72, a third liquefaction connection pipe 73, and a fourth liquefaction connection pipe 74, wherein the first liquefaction connection pipe 71 is connected with the first cargo tank CT1, the second liquefaction connection pipe 72 is connected with the second cargo tank CT2, the third liquefaction connection pipe 73 is connected with the third cargo tank CT3, and the fourth liquefaction connection pipe 74 is connected with the fourth cargo tank CT 4; the first liquefaction connection pipe 71, the second liquefaction connection pipe 72, the third liquefaction connection pipe 73, and the fourth liquefaction connection pipe 74 are connected in parallel and then connected to the liquefaction connection header pipe 7.

And the main exhaust pipe is connected between two adjacent cargo tanks and is used for conveying cargo vapor generated in the cargo tanks to other cargo tanks for nitrogen replacement. One end of the main exhaust pipe is an air inlet, the other end of the main exhaust pipe is an air outlet, the air inlet is connected to the top of the cargo tank, and the air outlet extends into the bottom of the adjacent cargo tank; so that a plurality of cargo tanks are connected in series.

Specifically, the main exhaust pipe includes first main exhaust pipe 91, second main exhaust pipe 92, third main exhaust pipe 93, fourth main exhaust pipe 94 at least, fourth main exhaust pipe 94 is used for connecting fourth cargo tank CT4 and third cargo tank CT3, third main exhaust pipe 93 is used for connecting third cargo tank CT3 and second cargo tank CT2, second main exhaust pipe 92 is used for connecting second cargo tank CT2 and first cargo tank CT1, and first main exhaust pipe 91 connects in the top of first cargo tank CT1 and upwards stretches out.

The auxiliary exhaust pipe is connected to the top of the liquid cargo tank; the plurality of auxiliary exhaust pipes extend upwards to be connected in parallel and then are connected to the auxiliary exhaust manifold 8; the liquefaction connection header 7 is connected in parallel with the secondary exhaust header 8.

The auxiliary exhaust pipe at least comprises: the auxiliary exhaust manifold 8, a first auxiliary exhaust pipe 81 arranged at the top of the first liquid cargo tank CT1, a second auxiliary exhaust pipe 82 arranged at the top of the second liquid cargo tank CT2, a third auxiliary exhaust pipe 83 arranged at the top of the third liquid cargo tank CT3 and a fourth auxiliary exhaust pipe 84 arranged at the top of the fourth liquid cargo tank CT 4; the first sub exhaust pipe 81, the second sub exhaust pipe 82, the third sub exhaust pipe 83, and the fourth sub exhaust pipe 84 are connected in parallel and collectively connected to the sub exhaust manifold 8.

The fourth liquefaction connection pipe 74 and the fourth sub-exhaust pipe 84 are the same pipe.

The flare stack 6 is connected to the top of the first cargo tank CT1 through the first main exhaust pipe 91, and the flare stack 6 is used for discharging tail gas such as nitrogen and burning cargo vapor.

In one embodiment, a connection pipe 10 is provided before the third auxiliary exhaust pipe 83 merges into the auxiliary exhaust manifold 8, one end of the connection pipe 10 is connected to the third auxiliary exhaust pipe 83, the other end of the connection pipe 10 is connected to the third main exhaust pipe 93, and the connection pipe 10 is used for discharging the cargo vapor in the third cargo tank CT3 to the second cargo tank CT2 for continuing the nitrogen substitution.

As shown in fig. 4, an auxiliary filling pipe 23 is connected between the filling pipe 2 and the condenser pipe 3, the filling pipe between the auxiliary filling pipe 23 and the tank car 1 is a first filling pipe 21, and the filling pipe between the auxiliary filling pipe 23 and the CT4 is a second filling pipe 22; the condenser pipe provided between the auxiliary filling pipe 23 and the tank car 1 is a first condenser pipe 31, and the condenser pipe provided between the auxiliary filling pipe 23 and the CT4 is a second condenser pipe 32.

In one embodiment, the first filling tube 21 and the second filling tube 22 are opened when a CT4 replacement is performed. In the cold room of CT4, the first condenser tube 31 and the second condenser tube 32 are opened. At the time of filling of CT4, the first condenser tube 31, the auxiliary fill tube 23, and the second fill tube 22 are opened.

According to a second aspect of the present application, as shown in fig. 1 to 6, there is also provided a gas ship gas combination test method, by which a gas combination test of a gas ship is completed by the gas combination test system of a gas ship provided in the first aspect, comprising the steps of:

s1, injecting gas-phase cargoes into the tank truck 1 to replace nitrogen in the fourth cargo tank CT4, and replacing nitrogen in the rest cargo tanks by using cargo steam generated in the fourth cargo tank CT 4.

As shown in fig. 2, the tank car 1 is supplied with low-temperature liquefied gas at a predetermined flow rate, is connected to a liquid phase pipeline of a loading and unloading station on a ship through a filling hose, is gasified and heated into normal-temperature gas-phase cargo through a valve 1, is injected into a tank of a fourth cargo tank CT4 through a bottom filling pipe 2, forms a layer with nitrogen in the tank, discharges nitrogen or mixed gas in the tank to a third cargo tank CT3 through a top exhaust pipe 1 through a piston effect, and continuously replaces the nitrogen in the third cargo tank CT 3. The fourth cargo tank CT4, the third cargo tank CT3, the second cargo tank CT2 and the first cargo tank CT1 are sequentially connected in series, and final tail gas is discharged to a torch to burn through an exhaust pipe 1 at the top of the first cargo tank CT 1.

Before step S1, the connection of the piping is completed, and the purge and tightness check work is completed. Before replacement, the liquid cargo tank is dried and inerted, and filled with nitrogen.

It should be noted that, since the ratio of the liquid and gas densities of the cargo such as LPG is about 200:1, the liquid should be controlled at a low flow rate during the displacement process. Low flow means a flow of 1.8-2.1t/h.

According to the application, only external cargo vapor is needed to replace nitrogen in the two tanks of the fourth cargo tank CT4 and the third cargo tank CT3 or in one tank of the fourth cargo tank CT4, and the specific number of replaced tanks is calculated and determined according to the volumes of a plurality of cargo tanks, the pressure to be maintained in the rear cold tank, the loaded cargo amount and the like.

In one embodiment, samples are taken from upper, middle and lower sampling points in the fourth cargo tank CT4 at regular time in the replacement process, the content of the cargo vapor at the sampling points is measured respectively, and the replacement is stopped when the content of the cargo vapor at each sampling point is greater than or equal to 95%.

And S2, when the volume content of the cargo vapor in the fourth cargo tank CT4 is more than or equal to 95%, starting the cold tank operation of the fourth cargo tank CT 4. The fourth cargo tank CT4 and the third cargo tank CT3 are connected in parallel with the cold tanks at the same time. The fourth cargo tank CT4 is cooled by spraying low-temperature liquefied gas in the tank car 1 of the wharf, and the third cargo tank CT3 is cooled after the cargo vapor generated in the fourth cargo tank CT4 is re-liquefied.

As shown in fig. 3, the low-temperature liquefied gas in the tank car 1 is atomized by a spray head at the stern of the fourth condenser pipe 3, and then sprayed and cooled into the fourth cargo tank CT4. The fourth condenser tube 3 is connected to the upper portion of the fourth cargo tank CT4, the atomized liquid has a high density, the atomized liquid absorbs heat and gasifies gradually in the descending process, the temperature in the fourth cargo tank CT4 is lowered, the produced cargo vapor can raise the pressure in the fourth cargo tank CT4, in order to control the pressure of the fourth cargo tank CT4, the third cargo tank CT3 is cooled in parallel, the reliquefaction part 5 is used to extract the cargo vapor from the fourth liquefaction connection tube 74, the reliquefaction part 5 liquefies the cargo vapor, and then injects the liquefied cargo vapor into the third cargo tank CT3 through the third liquefaction connection tube 73, and the third cargo tank CT3 is cooled in a spraying manner. The cargo vapor in the fourth cargo tank CT4 is liquefied by the reliquefaction part 5 and then is conveyed to the third cargo tank CT3 for parallel cooling, so that the simultaneous cooling of the fourth cargo tank CT4 and the third cargo tank CT3 is realized, the pressure stability in the fourth cargo tank CT4 can be ensured, and meanwhile, the next cargo tank can be cooled by utilizing the cargo vapor. Compared with the prior art, the method has the advantages that the cargo steam is discharged and combusted, so that the economy can be improved, and meanwhile, the environment is protected.

In the cold tank process, the temperature and pressure changes in the fourth cargo tank CT4 and the third cargo tank CT3 are measured in real time, so that the temperature drop rate is not more than 10 ℃/h, and the pressure in the tank is not more than the set pressure value of the safety valve.

As shown in fig. 3, in the cooling process of the third cargo tank CT3, since the third cargo tank CT3, the second cargo tank CT2, and the first cargo tank CT1 are connected in series, the cargo vapor generated by the endothermic gasification of the third cargo tank CT3 is utilized to replace the nitrogen in the second cargo tank CT2 and the first cargo tank CT1 through the main exhaust pipe connected between the two adjacent cargo tanks, and then the flare is discharged through the first main exhaust pipe 91 at the top of the first cargo tank CT1. The third cargo tank CT3, the second cargo tank CT2, and the first cargo tank CT1 are connected in series, so that cargo vapor can be replaced by the second cargo tank CT2 and the first cargo tank CT1. The goods vapor generated in the cold cabin process is fully utilized, and the cold cabin, the replacement time and the goods consumption are greatly saved.

The step S3 further includes: as shown in fig. 3, the cargo vapor in the third cargo tank CT3 is discharged to the second cargo tank CT2 through the connection pipe 10, and the nitrogen gas substitution is continued. Because the temperature of the cargo vapor in the third cargo tank CT3 is lower, the density is higher than the original normal-temperature nitrogen in the second cargo tank CT2, so that the cargo vapor and the nitrogen can be conveniently and well layered after being injected from the bottom of the second cargo tank CT2, a piston effect is formed, and the replacement efficiency is improved.

In one embodiment, after step S3 is completed, the temperatures of the fourth cargo tank CT4 and the third cargo tank CT3 reach-40 ℃, and the vapor volume content of the second cargo tank CT2 hold cargo is greater than or equal to 95%.

And S4, after the fourth cargo tank CT4 and the third cargo tank CT3 finish the cold tanks, filling the fourth cargo tank CT 4.

As shown in fig. 4, when filling CT4, the first condenser tube 31, the auxiliary filler tube 23, and the second filler tube 22 are opened.

As shown in fig. 4, the liquid cargo in the tank car 1 is injected into the bottom of the fourth liquid cargo tank CT4, a large amount of cargo vapor is generated during the filling process, which results in the pressure increase of the fourth liquid cargo tank CT4, and the residual liquid cargo in the bottom of the third liquid cargo tank CT3 is evaporated due to the heat invasion of the outside, so that the cargo vapor in the fourth liquid cargo tank CT4 and the third liquid cargo tank CT3 is extracted through the re-liquefying mechanism, is liquefied into liquid, then injected into the second liquid cargo tank CT2 through the second liquefying connection pipe 72, and is sprayed and cooled, the cargo vapor generated by spraying and cooling the second liquid cargo tank CT2 is injected into the first liquid cargo tank CT1 through the second main exhaust pipe 92, replaces nitrogen in the first liquid cargo tank CT1, and is discharged to the flare tower 6 through the first main exhaust pipe 91. The cargo vapor generated in the filling process is fully utilized to cool the second cargo tank CT2, and the cargo vapor generated by the second cargo tank CT2 cold tank is utilized to replace the first cargo tank CT1, so that the liquid cargo filling of the fourth cargo tank CT4, the cold tank of the second cargo tank CT2 and the replacement of the first cargo tank CT1 are simultaneously carried out, and additional cargo is not required to be consumed, so that the cold tank, the replacement time and the cargo consumption are saved.

The liquid level of the fourth cargo tank CT4, the temperature of the second cargo tank CT2, and the volume concentration of the cargo vapor in the first cargo tank CT1 are acquired in real time. And stopping filling when the liquid level of the fourth cargo tank CT4 reaches a required value. Stopping the operation of the reliquefaction mechanism if the temperature of the second cargo tank CT2 reaches-40 ℃ and the cargo vapor volume concentration of the first cargo tank CT1 is more than or equal to 95%; if the temperature of the second cargo tank CT2 and the volume concentration of the cargo vapor in the first cargo tank CT1 do not reach the predetermined range, the re-liquefying mechanism continues to operate until it reaches.

And S5, after filling of the fourth cargo tank CT4 is completed, removing pipelines between the fourth cargo tank CT4 and the tank car 1 and the flare tower 6, and enabling the ship to leave the wharf and go to a preset offshore area for sea test. During sailing, as shown in fig. 5, cargo vapor generated in the fourth cargo tank CT4, the third cargo tank CT3, the second cargo tank CT2, and the first cargo tank CT1 due to external heat is extracted by the reliquefaction mechanism to control the tank pressure, and at the same time, the first cargo tank CT1 is cooled and cooled to-40 ℃.

In this embodiment, the replacement, cooling and filling of the four cargo tanks are all completed at the dock.

In summary, the application changes the serial-parallel connection mode among liquid cargo tanks in different operation stages, fully utilizes the cargo vapor generated in the processes of front tank replacement, cold tank and filling to replace and cool the rear tank, realizes the efficient utilization of the cargo vapor, and saves the air test time. The replacement of a plurality of cargo tanks can be satisfied by only introducing gas cargo into one cargo tank; through the arrangement of the reliquefaction mechanism, a plurality of cabins are connected with the cold cabins in parallel in the cold cabin stage of the fourth cargo tank; and the parallel operation of filling, cooling and replacement is realized in the filling stage of the fourth cargo tank. The application realizes the maximum utilization of the cargo steam, saves a large amount of cargoes in the gas test, prevents the cargo steam from being discharged to the atmosphere, avoids polluting the environment, greatly saves the gas test time and improves the economy of the gas test.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and substitutions can be made by those skilled in the art without departing from the technical principles of the present invention, and these modifications and substitutions should also be considered as being within the scope of the present invention.

Claims

1. A gas combination test system for a gas ship, comprising:

The tank car is used for containing low-temperature liquefied gas;

2. The gas combination test system of a gas ship according to claim 1, wherein the pipeline in which the reliquefaction part is located is a liquefaction connection header pipe;

3. The gas ship's gas combination test system of claim 2, further comprising a secondary exhaust pipe connected to the top of the cargo tank for delivering cargo vapors in the corresponding cargo tank;

4. A gas ship gas combination test system according to claim 3, wherein the fourth liquefaction connection pipe and the fourth auxiliary exhaust pipe are the same pipeline; the liquefaction connecting main pipe is connected with the auxiliary exhaust main pipe in parallel.

5. The gas ship's gas combination test system according to claim 4, wherein the main exhaust pipe includes at least a first main exhaust pipe, a second main exhaust pipe, a third main exhaust pipe, a fourth main exhaust pipe, the fourth main exhaust pipe being for connecting a fourth cargo tank and a third cargo tank, the third main exhaust pipe being for connecting a third cargo tank and a second cargo tank, the second main exhaust pipe being for connecting the second cargo tank and a first cargo tank, the first main exhaust pipe being connected to a top of the first cargo tank and extending upward.

6. The gas ship's gas combination testing system of claim 5, further comprising a flare stack connected to a top of the first cargo tank via a first main exhaust pipe, the flare stack configured to vent tail gases such as nitrogen and incinerate cargo vapors.

7. The gas ship's gas combination test system according to claim 6, wherein a connection pipe is provided before the third sub exhaust pipe merges into the sub exhaust manifold, one end of the connection pipe is connected to the third sub exhaust pipe, the other end of the connection pipe is connected to the third main exhaust pipe, and the connection pipe is used for discharging cargo vapor in the third cargo tank to the second cargo tank to continue nitrogen substitution.

8. A gas combination test of a gas ship, characterized in that the gas combination test of the gas ship is completed by a gas combination test system of a gas ship according to any one of claims 1 to 7, comprising the steps of:

9. The gas combination test method of a gas ship according to claim 8, wherein in step S2, the fourth cargo tank and the third cargo tank are simultaneously connected in parallel with the cold tank; the fourth cargo tank is cooled by spraying low-temperature liquefied gas in a tank car of the wharf, and the third cargo tank is cooled by a re-liquefying mechanism.

10. The gas ship gas combination test method according to claim 8, wherein in step S4, the cargo vapors in the fourth cargo tank and the third cargo tank are pumped by the re-liquefying mechanism to be liquefied, and then injected into the second cargo tank through the second liquefying connection pipe, and the second cargo tank is sprayed and cooled, and the cargo vapors generated by spraying and cooling the second cargo tank are injected into the first cargo tank through the second main exhaust pipe, replace nitrogen in the first cargo tank, and are discharged to the flare tower through the first main exhaust pipe.