A method for LNG carrier gas trial project consolidation and matching

Abstract

The application discloses a method for LNG transport ship gas test project combination and matching, comprising the following steps: simultaneously performing a large-flow combustion test of a self-flow gas supply mode of a GCU at the end of a cold cabin of a primary cooling cargo hold; after the end of the cold cabin of the primary cooling cargo hold, simultaneously performing a process of a GCU flow test controlled by a gas management system (GMS); simultaneously performing a forced vaporizer maximum flow function debugging and a compressor gas supply mode endurance test of the GCU; simultaneously performing energy consumption tests of a main engine at different speeds and different powers in an unmanned engine room project in an engine room gas mode and a GMS automatic control forced vaporizer flow test; and simultaneously performing a LNG ship cargo hold temperature rising process and a ship speed measurement process. The application can reduce test time, reduce test cost, reduce carbon emission, and improve stability and safety of a gas system, and can not only improve operation efficiency of the LNG transport ship, but also make contribution to global environmental protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LNG carrier gas trial, and particularly relates to a method for combining and matching LNG carrier gas test projects. BACKGROUND

[0002] During the operation of a liquefied natural gas (LNG) carrier, the performance and safety of the gas system are of great importance. Therefore, during the gas trial phase of the LNG carrier, in order to verify the operating conditions and performance of the ship's gas system and equipment in the gas mode and to ensure the normal operation of the ship's gas system and equipment in the gas mode, a series of gas test projects need to be carried out. These tests aim to verify the working state, performance and safety of each component of the system in the gas mode. However, in the existing technology, these test projects are usually carried out separately. This means that in order to complete all the tests, a large amount of time and natural gas is consumed to achieve different gas system test conditions, which not only increases the test time but also increases the test cost. The practice of carrying out each sub-test separately is more likely to affect the future operation of the ship, as the tests carried out during the gas trial are mostly extreme conditions of the equipment or system, and multiple start-ups and stoppages can affect the stability and lifespan of the ship. The need to adjust the parameters of the gas system multiple times also increases the complexity of operation and the possibility of human error. Moreover, the existing practice results in additional carbon emissions, which is contrary to the current global focus on environmental protection.

[0003] Therefore, in order to solve the above problems, a method is needed that can combine and optimize these test projects. The new method should be able to reduce test time, reduce test cost, reduce carbon emissions, and improve the stability and safety of the gas system. This not only improves the operational efficiency of the LNG carrier, but also contributes to global environmental protection. SUMMARY

[0004] Therefore, the present application provides a method for combining and matching LNG carrier gas test projects to solve the problems in the background art.

[0005] A method for combining and matching LNG carrier gas test projects, specifically comprising the following steps:

[0006] S1, cooling the cargo hold of the LNG carrier at the dock, and simultaneously carrying out a large-flow combustion test in self-flow gas supply mode of the GCU at the end of the cold hold of the primary cooling cargo hold;

[0007] S2, after the end of the cold hold of the primary cooling cargo hold, the process of the GCU flow test controlled by the gas management system (GMS) is carried out simultaneously;

[0008] S3, on the wharf or after the ship is berthed to the gas station, debugging the maximum flow function of the forced vaporizer outside the cargo hold, and simultaneously carrying out the compressor gas supply mode endurance test of the gas combustion unit (GCU);

[0009] S4, during the berthing of the ship at the gas station, synchronously carrying out the energy consumption test of the main engine at different speeds in the unmanned engine room project in the engine gas mode and the forced vaporizer flow test automatically controlled by the gas management system (GMS);

[0010] Synchronization of the main engine power increase and decrease test in the unmanned engine room project in the engine gas mode and the forced vaporizer flow test automatically controlled by the gas management system (GMS);

[0011] S5, synchronizing the LNG ship cargo hold warming process with the ship speed measurement process to save the time loss during the sea warming period.

[0012] Preferably, the specific steps of step S1 are:

[0013] First, the cargo hold of the LNG transport ship is cooled on the wharf;

[0014] When the cooling operation of the first cold cargo hold is about to reach the end of the cold hold, the volatile gas main of the first cold cargo hold is separated from other cargo holds by a valve, and the volatile gas pipe of the first cold cargo hold is connected to the gas inlet of the gas combustion unit (GCU) through a high load heater;

[0015] When the first cold cargo hold reaches the end of the cold hold, the amount of natural gas replacement between the first cold cargo hold and the non-first cold cargo hold is reduced, and the volatile gas formed in the first cold cargo hold is supplied to the GCU through the volatile gas pipe, and the self-flow gas supply mode large flow combustion test of the GCU is simultaneously carried out.

[0016] Preferably, when the first cold cargo hold reaches the end of the cold hold, the cabin pressure in the first cold cargo hold reaches a high cabin pressure range of 15KPa-25KPa, and the self-flow gas supply mode large flow combustion test of the GCU is simultaneously carried out.

[0017] Preferably, in step S2, after the 21st hour of the cold hold of the first cold cargo hold, the subsequent cargo hold cooling process is synchronized with the GMS controlled GCU flow test process, and the volatile gas formed in the first cold cargo hold can be completely consumed by the GCU, and the natural gas replacement gas path between the first cold cargo hold and the non-first cold cargo hold needs to be cut off.

[0018] Preferably, when the maximum flow function of the forced vaporizer is debugged in step S3 synchronously with the compressor gas supply mode endurance test of the GCU, the supply pressure set value of the gas pump in the cargo hold should not be lower than the outlet pressure set value of the LD compressor in the GCU. When the flow of the forced vaporizer is increased to more than 50%, the supply pressure of the gas pump can be gradually set to 130% of the outlet flow of the LD compressor, but should not be higher than the take-off set value of the gas pipe safety valve, so as to ensure the increase of the outlet flow of the forced vaporizer.

[0019] Preferably, when the maximum flow function of the forced vaporizer is debugged in step S3 synchronously with the compressor gas supply mode endurance test of the GCU, the flow set value of the LD compressor in the GCU should be always kept 5-8% higher than the outlet flow of the forced vaporizer, so as to ensure that the outlet flow of the forced vaporizer is always consumed by the GCU and steadily increased, and the pressure in the cargo hold is always kept within the controllable range during the test.

[0020] Preferably, when the maximum flow function of the forced vaporizer is debugged in step S3 synchronously with the compressor gas supply mode endurance test of the GCU, when the maximum flow of the GCU in the LD compressor gas supply mode is reached, the maximum combustion flow of the GCU is kept and the gas supply pipe network OPV valve is gradually opened manually. After each time the OPV valve is opened, the outlet flow of the forced vaporizer is gradually increased.

[0021] During the process of gradually opening the gas supply pipe network OPV valve, the condensate amount of the forced vaporizer and the LD heater in the GCU is continuously monitored. If the condensate amount of the forced vaporizer and the LD heater in the GCU is too high in a short time, the outlet flow of the forced vaporizer should be gradually reduced to keep the condensate amount controllable. Through this process, the maximum flow of the forced vaporizer is reached, and the test conditions of the GCU in the LD compressor gas supply mode are also matched. Therefore, it is not necessary to specially consume natural gas for the compressor gas supply mode endurance test of the GCU.

[0022] Preferably, during the process of gradually opening the gas supply pipe network OPV valve, the opening range of the OPV valve is 1% each time, so as to keep the pressure of the gas supply pipe stable and the GCU stable combustion. After each time the OPV valve is opened, the outlet flow of the forced vaporizer can be gradually increased, and the increase range is within 3%. After the pipe pressure of the gas supply pipe network is stable, the OPV valve can be continuously opened.

[0023] Preferably, in step S4, when the energy consumption test of the main engine at different speeds in the unmanned engine gas mode project is carried out synchronously with the automatic control of the forced vaporizer flow test of the gas management system (GMS), 100% flow of the GCU is set as the rated maximum gas consumption of the main engine, the actual gas consumption of the main engine at different speeds is simulated by increasing the gas flow of the GCU, the GCU transmits the gas flow to the ship automation control system (IAS) in real time, and the GMS automatically adjusts the outlet flow of the forced vaporizer according to the change of the tank pressure in the liquid cargo tank, and synchronously adjusts the outlet flow of the gas pump.

[0024] When the main engine power increase and decrease test in the unmanned engine gas mode project is carried out synchronously with the automatic control of the forced vaporizer flow test of the gas management system (GMS), 100% flow of the GCU is set as the rated maximum gas consumption of the main engine, the actual gas consumption of the main engine at different powers is simulated by increasing the gas flow of the GCU, the GCU transmits the gas flow to the ship automation control system (IAS) in real time, and the GMS automatically adjusts the outlet flow of the forced vaporizer according to the change of the tank pressure in the liquid cargo tank, and synchronously adjusts the outlet flow of the gas pump.

[0025] In the execution process of the step, only the gas pump with the liquid cargo tank is operated, and the remaining non-liquid cargo tanks are operated after the liquid cargo tank completes partial unloading to the gas station.

[0026] Preferably, in step S5, when the LNG ship cargo tank warming process is carried out synchronously with the ship speed measurement process, the non-liquid cargo tank needs to have completed the first stage of the large expansion amount of the warming operation, and when the warming operation of the liquid cargo tank is carried out, the expansion amount of the liquid cargo tank is slowly absorbed by the GCU and the non-liquid cargo tank, greatly shortening the discharge time of the venting mast, so that a large number of non-explosion-proof equipment required during the speed measurement test can be safely used.

[0027] The beneficial effects of the present application are:

[0028] 1. The present application matches the "GCU self-flow gas supply mode large flow combustion test" with the cold tank end of the primary cooling cargo tank, and gradually reduces the gas displacement amount between the primary cooling cargo tank and the non-primary cooling cargo tank to supply volatile gas to the GCU for the self-flow gas supply mode large flow combustion test, which can gradually reduce the volatile amount of the loaded LNG after the cold tank and reduce the loss.

[0029] 2. After the cold tank end of the primary cooling cargo tank is completed, the "gas management system (GMS) controls the GCU flow test" is carried out synchronously, the volatile gas amount in the cargo tank can be effectively covered by the GCU combustion gas consumption flow, which can not only improve the accuracy and reliability of the gas test, but also realize the GCU flow test as soon as possible, so that the support equipment can reach the available state in advance, and the safety hidden danger of each operation after the cold tank of the LNG ship is reduced.

[0030] 3、The present application synchronizes the "debugging forced vaporizer maximum flow function" with the "compressor gas supply mode durability test of the gas combustion device (GCU)", and when the forced vaporizer maximum flow test is completed, the GCU in the LD compressor gas supply mode is also matched to complete the flow test condition, and there is no need to specially consume natural gas for the test process of the latter.

[0031] 4、The present application synchronizes the "main engine energy consumption test at different speeds and different powers in the unmanned engine room project in the gas mode" with the "automatic control forced vaporizer flow test of the gas management system (GMS)", so that even if the LNG ship is in gas station berthing during the actual operation of the main engine, the actual consumption of the main engine at different speeds and different powers can be accurately simulated through the GCU combustion consumption.

[0032] 5、The present application synchronizes the LNG ship cargo hold warming process with the ship speed measurement process, and at this time the non-liquid cargo hold needs to have completed the first stage of the large expansion amount of the warming operation, and when the liquid cargo hold is warmed, the expansion amount of the liquid cargo hold will be slowly absorbed by the GCU and the non-liquid cargo hold, so that the phenomenon of rapid increase of the cargo hold pressure no longer occurs, the discharge time of the gas venting mast can be greatly shortened, a large number of non-explosion-proof equipment required during the speed measurement test can be safely used, and the time loss during the sea warming period can also be saved.

[0033] 6、The present application can reduce test time, reduce test cost, reduce carbon emissions, and improve the stability and safety of the gas system. Not only can the operating efficiency of the LNG transport ship be improved, but also the global environmental protection industry can be contributed. The present application has been tested on 6 LNG ships during gas trial, and has strong feasibility and repeatability, and is a necessary and new method for the development of the industry, providing more efficient and environmentally friendly technical support for the test and trial of the LNG transport ship and the operation after delivery.

[0034] According to the average value analysis of the test results of the 6 LNG ships that have completed the practice, the implementation effect of the present application greatly reduces the test medium loss, and each LNG ship can save 493m3 of LNG consumption, which is equivalent to: 493*0.44*6500 (yuan / ton) / 10000 = 14.1 million yuan;

[0035] Each LNG ship can save 1 day of gas station window, and each ship can save 1 million yuan of gas station service fee;

[0036] Due to the autonomous research and real ship verification, the embodiment innovatively implements a large number of new LNG ship gas trial initiatives, and the related technical achievements are self-controllable, compared with the cost of outsourcing expert assistance trial, each ship can save outsourcing cost: 1450 (euro / person*day) * 7.5 (exchange rate) * 7 (number of people) * 16 (number of days saved) / 10000 = 122 million yuan;

[0037] According to the enterprise of the applicant, 7 LNG ship gas trial tasks are completed per year, which can save the company a total of 2541 million yuan per year: (122+100+141) *7 = 2541 million yuan. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0039] Figure 1 In order to match the large flow combustion test of the self-flow gas supply mode of the gas combustion device with the process of simultaneously carrying out the process of cargo hold temperature reduction.

[0040] Figure 2 In the present application, the cargo hold temperature reduction process is synchronized with the GMS controlled GCU flow test process.

[0041] Figure 3 In the present application, the gas pump running process during the forced vaporizer debugging.

[0042] Figure 4 In the present application, the speed test process during the cabin warming process.

[0043] Figure 5 Flow chart of the method of the present application. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present application more clear and obvious, the following describes the present application through specific embodiments shown in the drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0045] The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used in the present disclosure and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term "and / or," as used herein, refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0046] For better understanding of the technical solutions of the present application, the present application is described in detail below in combination with the drawings.

[0047] The present application provides a method for LNG carrier gas test project merging and matching, which specifically comprises the following steps:

[0048] S1, cooling the cargo hold of the LNG carrier on the wharf, and simultaneously carrying out free flow mode large flow combustion test of the gas combustion device (GCU) at the end of the cold cargo hold of the first cold cargo hold.

[0049] Specifically, first, the cargo hold of the LNG carrier is cooled on the wharf, and in the present embodiment, 1-2 tank trucks loaded with liquid LNG are used to fill gas on the wharf to cool the cargo hold of the LNG carrier;

[0050] When the cooling operation of the first cold cargo hold is about to reach the end of the cold cargo hold, the vapor header of the first cold cargo hold is separated from other cargo holds by a valve, and the vapor pipe of the first cold cargo hold is connected to the gas inlet of the gas combustion device (GCU) through a high load heater (HDHeater);

[0051] When the first cold cargo hold reaches the end of the cold cargo hold, the amount of natural gas replacement between the first cold cargo hold and the non-first cold cargo hold is reduced, and the volatile gas formed in the first cold cargo hold is supplied to the GCU through the volatile gas pipe, and the free flow mode large flow combustion test of the GCU is simultaneously carried out.

[0052] The first cooling cargo hold refers to the cargo hold that is first cooled, and the cargo hold with the smallest hold capacity among all the cargo holds is taken as the first cooling cargo hold. The late cooling stage of the first cooling cargo hold refers to the period between the 10th and 21st hours of cooling of the first cooling cargo hold. Before this period, the volatile gas formed in the first cooling cargo hold is supplied to the top of the non-first cooling cargo hold through the volatile gas header as the gas source for natural gas replacement by the high-load heater. When the first cooling cargo hold enters the late cooling stage, the amount of natural gas replacement between the first cooling cargo hold and the non-first cooling cargo hold is gradually reduced, and the volatile gas formed in the first cooling cargo hold is supplied to the GCU through the volatile gas header, so that the volatile gas formed in the first cooling cargo hold is used as the fuel of the GCU to perform the large-flow combustion test of the GCU in the self-flow gas supply mode. In the embodiment, the outlet temperature of the high-load heater is preferably controlled at 25-30 degrees Celsius.

[0053] The large-flow combustion test of the GCU in the self-flow gas supply mode is performed between the 10th and 21st hours of cooling of the first cooling cargo hold, which can ensure that the cooling spray consumption in the first 10 hours of the rated cooling time is within the theoretical range, and the gas flow for gas replacement is reduced after this period to perform the GCU self-flow gas supply test, which will cause the pressure in the first cooling cargo hold to rise, thereby gradually reducing the evaporation amount of the LNG loaded in the rear cooling hold and reducing the loss. The above operation can match the working condition of the next step.

[0054] During the large-flow combustion test of the GCU in the self-flow gas supply mode, a higher hold pressure is required to achieve stable combustion, which is just the case when the evaporation amount of the first cooling cargo hold gradually decreases, so the test is performed at a higher hold pressure to ensure stable operation of the GCU test. Preferably, when the hold pressure in the first cooling cargo hold reaches a high hold pressure range of 15-25 KPa, the large-flow combustion test of the GCU in the self-flow gas supply mode is simultaneously performed.

[0055] S2, after the late cooling stage of the first cooling cargo hold ends (i.e., after the 21st hour of cooling of the first cooling cargo hold), the process of the GCU flow test controlled by the gas management system (GMS) is simultaneously performed.

[0056] After the 21st hour of cooling of the first cooling cargo hold, the first cooling cargo hold continues to be cooled, and the process of the GCU flow test controlled by the gas management system (GMS) is simultaneously performed.

[0057] During the GMS control GCU flow test, the heat exchange between the cargo hold and the cargo hold insulation layer has gradually tended to a lower and stable level. In this stage, the main and secondary insulation layers of the liquid cargo hold and the heat exchange in the hold are mainly used to evaporate the liquid LNG in the hold, so the amount of volatile gas formed by natural evaporation in the first cold cargo hold can be completely consumed by the GCU combustion. In this case, the natural gas replacement gas path between the first cold cargo hold and the non-first cold cargo hold can be safely cut off to meet the prerequisite requirements of the "GMS control GCU flow test" and improve the accuracy and reliability of the gas test, and the GCU test is realized as soon as possible, so that the safety equipment reaches the available state in advance, and the safety hidden danger of each operation after the LNG ship cold cabin is reduced.

[0058] S3, on the wharf or after the ship is berthed to the gas station, debug the maximum flow function of the forced vaporizer outside the cargo hold, and simultaneously perform a compressor gas supply mode durability test of the gas combustion device (GCU).

[0059] In this stage, the forced vaporization of the forced vaporizer is used to force the gasification of the gas LNG as the fuel of the GCU.

[0060] When the forced vaporizer maximum flow function is debugged and the GCU compressor gas supply mode durability test is simultaneously performed, the liquid supply pressure set value of the gas pump in the cargo hold should not be lower than the outlet pressure set value of the LD compressor in the GCU. When the forced vaporizer flow is increased to more than 50%, the liquid supply pressure of the gas pump can be gradually set to 120-130% of the LD compressor outlet flow but not higher than the take-off set value of the gas pipe safety valve, to ensure the increase of the forced vaporizer outlet flow. Preferably, when the forced vaporizer flow is increased to more than 50%, the liquid supply pressure of the gas pump can be gradually set to 130% of the LD compressor outlet flow but not higher than the take-off set value of the gas pipe safety valve.

[0061] As a preferred, the outlet temperature of the low load heater (i.e. LD heater) is set to control at 25-30 degrees Celsius.

[0062] As preferred, when the forced vaporizer maximum flow function is debugged and synchronized with the GCU compressor supply mode endurance test, the flow rate setting of the LD compressor supply mode in the GCU should be always kept 5-8% higher than the outlet flow rate of the forced vaporizer, so as to ensure that the outlet flow rate of the forced vaporizer is always consumed and steadily increased by the GCU and the cargo hold pressure is always kept within the controllable range during the test period, in the case that the main engine of the ship is not running. If the GCU combustion amount is too different from the outlet flow rate of the forced vaporizer, the flow rate of the LD compressor will be increased too much, the load fluctuation of the gas phase pipeline of the supply system will be increased, and the system will be unstable. If the GCU combustion amount is too low compared with the outlet flow rate of the forced vaporizer, the outlet flow rate of the forced vaporizer will not be increased smoothly, and it is easy to continuously operate until the GCU flow rate reaches the maximum flow rate of the LD compressor supply mode.

[0063] As preferred, when the forced vaporizer maximum flow function is debugged and synchronized with the GCU compressor supply mode endurance test, the flow rate setting of the LD compressor supply mode in the GCU should be always kept 5-8% higher than the outlet flow rate of the forced vaporizer, so as to ensure that the outlet flow rate of the forced vaporizer is always consumed and steadily increased by the GCU and the cargo hold pressure is always kept within the controllable range during the test period, in the case that the main engine of the ship is not running. If the GCU combustion amount is too different from the outlet flow rate of the forced vaporizer, the flow rate of the LD compressor will be increased too much, the load fluctuation of the gas phase pipeline of the supply system will be increased, and the system will be unstable. If the GCU combustion amount is too low compared with the outlet flow rate of the forced vaporizer, the outlet flow rate of the forced vaporizer will not be increased smoothly, and it is easy to continuously operate until the GCU flow rate reaches the maximum flow rate of the LD compressor supply mode.

[0064] As preferred, during the process of gradually opening the supply pipeline network OPV valve, the OPV valve is opened by 1% each time to keep the pressure of the gas pipeline in the supply pipeline network stable and the GCU stable combustion. After the OPV valve is opened each time, the outlet flow rate of the forced vaporizer can be continued to be gradually increased by within 3%, and the OPV valve is continued to be opened after the pipeline pressure of the supply pipeline network is stable.

[0065] As preferred, during the process of gradually opening the supply pipeline network OPV valve, the condensate amount of the forced vaporizer and the LD heater in the GCU is continuously monitored. If the condensate amount of the forced vaporizer and the LD heater in the GCU is too high in a short time, the outlet flow rate of the forced vaporizer should be gradually reduced to keep the condensate amount controllable. Through this process, the maximum flow rate of the forced vaporizer can be reached, and the GCU in the LD compressor supply mode is matched and completed at the same time. Therefore, it is not necessary to specially consume natural gas for the GCU compressor supply mode endurance test.

[0066] The flow rate adjustment of the forced vaporizer in this step is controlled by the ship automation control system (IAS).

[0067] This step can be carried out at the wharf, or the ship can be berthed at the gas station.

[0068] S4, during the period of berthing at the gas station, the energy consumption test of the main engine at different speeds in the unmanned engine room project in the engine room gas mode is carried out synchronously with the automatic control of the forced vaporizer flow test of the gas management system (GMS), and the main engine power increase and decrease test in the unmanned engine room project in the engine room gas mode is carried out synchronously with the automatic control of the forced vaporizer flow test of the gas management system (GMS).

[0069] Specifically, when the energy consumption test of the main engine of the ship at different speeds in the unmanned engine room project in the engine room gas mode is carried out synchronously with the automatic control of the forced vaporizer flow test of the gas management system (GMS) in the ECOBOT project, the 100% flow of the GCU is set as the rated maximum gas consumption of the main engine, the actual gas consumption of the main engine at different speeds is simulated by increasing and decreasing the gas flow of the GCU, the GCU transmits the gas flow to the ship automation control system (IAS) in real time, the GMS automatically adjusts the outlet flow of the forced vaporizer according to the change of the tank pressure in the liquid cargo tank, and at the same time, the outlet flow of the gas pump is automatically adjusted synchronously through the load controller to improve the outlet flow of the pump. Even if the main engine is not actually running during the berthing period of the LNG ship at the gas station, the actual gas consumption of the main engine at different speeds can be accurately simulated by the GCU combustion consumption, and the functional debugging of the automatic increase and decrease of the load of the forced vaporizer by the GMS can be realized.

[0070] When the main engine power increase and decrease test in the unmanned engine room project in the engine room gas mode is carried out synchronously with the automatic control of the forced vaporizer flow test of the gas management system (GMS), the 100% flow of the GCU is set as the rated maximum gas consumption of the main engine, the actual gas consumption of the main engine at different powers is simulated by increasing and decreasing the gas flow of the GCU, the GCU transmits the gas flow to the ship automation control system (IAS) in real time, the GMS automatically adjusts the outlet flow of the forced vaporizer according to the change of the tank pressure in the liquid cargo tank, and at the same time, the outlet flow of the gas pump is automatically adjusted synchronously through the load controller to improve the outlet flow of the pump. Even if the main engine is not actually running during the berthing period of the LNG ship at the gas station, the actual gas consumption of the main engine at different powers (energy consumption) can be accurately simulated by the GCU combustion consumption, and the functional debugging of the automatic increase and decrease of the load of the forced vaporizer by the GMS can be realized.

[0071] In order to ensure the safety and accuracy of the test, when the cargo tank pressure is less than 12Kpa, this step test is carried out to ensure that the cargo tank has enough pressure rising space. In the test process, the 100% flow of the GCU is set as the rated maximum gas consumption value of the main engine.

[0072] When this step test is carried out, only one LD compressor can run to match the low cargo tank pressure condition when the LNG ship is ballasted and sailing, and the GCU always maintains a large load combustion of 50% to 100% to match the main engine gas consumption condition corresponding to high speed.

[0073] In the test of the present step, only the gas pump of the liquid-carrying cargo tank is operated, and the remaining non-liquid-carrying cargo tanks are warmed up after the liquid-carrying cargo tank completes partial unloading to the gas station. The duration of the warming-up operation is more than 8 hours, so as to match the next step (i.e., the working condition of matching the subsequent cargo tank warming-up process with the ship speed test process).

[0074] The liquid-carrying cargo tank refers to a cargo tank storing liquid LNG, and the non-liquid-carrying cargo tank refers to an empty cargo tank. In the present embodiment, during the test, there is one liquid-carrying cargo tank and three non-liquid-carrying cargo tanks.

[0075] S5, synchronizing the LNG ship cargo tank warming-up process with the ship speed test process to save the time loss of the sea warming-up period.

[0076] When the LNG ship cargo tank warming-up process is synchronized with the ship speed test process, all the non-liquid-carrying cargo tanks need to have completed the first-stage warming-up operation with a large expansion volume (i.e., the duration of the warming-up operation is more than 8 hours). When the warming-up operation of the liquid-carrying cargo tank is performed, the expansion volume caused by the heated and volatilized natural gas is slowly absorbed by the GCU and the non-liquid-carrying cargo tank, so that the phenomenon of the dramatic increase of the cargo tank pressure no longer occurs. Therefore, the venting time of the venting mast can be greatly shortened, and a large number of non-explosion-proof equipment required during the speed test can be safely used.

[0077] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

Claims

1. A method for merging and matching gas test items for LNG carriers, characterized in that, Specifically, the following steps are included: S1, cool the cargo hold of the LNG carrier at the dock, and simultaneously conduct a high-flow combustion test of the gas combustion unit (GCU) in self-flowing gas supply mode at the end of the first cooling cargo hold. Specifically, firstly, the cargo holds of the LNG carrier are cooled at the dock; When the cooling operation of the first cold cargo hold is about to reach the end of the cold hold period, the volatile gas main of the first cold cargo hold is isolated from other cargo holds by valves, and the volatile gas pipe of the first cold cargo hold is connected to the air inlet of the gas combustion unit (GCU) through a high-load heater. When the first-cooled cargo tank reaches the end of its cooling period, the amount of natural gas replaced between the first-cooled cargo tank and the non-first-cooled cargo tank is reduced, and the volatile gas formed in the first-cooled cargo tank is supplied to the GCU through the volatile gas pipe. At the same time, a high-flow combustion test of the GCU's gravity-flow gas supply mode is carried out. S2, after the end of the cold storage period in the first cold cargo hold, the gas management system (GMS) controls the GCU flow test simultaneously; S3, at the dock or after the ship is moored to the gas station, adjust the maximum flow function of the forced vaporizer outside the cargo hold, and simultaneously conduct a durability test of the GCU's compressor gas supply mode. S4. While the ship is berthed at the gas station, the energy consumption test of the main engine at different speeds and the flow test of the GMS automatic control forced vaporizer in the unmanned engine room project under the engine room gas mode will be carried out simultaneously. In the unmanned cabin project under cabin gas mode, the main engine power increase / decrease test and the GMS automatic control forced vaporizer flow test were carried out simultaneously. S5 synchronizes the LNG ship cargo hold heating process with the ship speed measurement process, saving time lost during the sea warming period. In step S5, when the LNG carrier cargo tank heating process is carried out simultaneously with the ship speed measurement process, the non-liquid cargo tanks must have completed the first stage of warming operations with a large expansion. When the liquid cargo tanks are warmed, the expansion of the liquid cargo tanks is slowly absorbed by the GCU and the non-liquid cargo tanks, which greatly shortens the ventilation mast discharge time and allows a large number of non-explosion-proof equipment required during the speed measurement test to be used safely.

2. The method for merging and matching LNG carrier gas test items according to claim 1, characterized in that, At the end of the first cold storage period, when the tank pressure in the first cold storage reaches the high tank pressure range of 15KPa-25KPa, a high-flow combustion test of the GCU in the self-flowing gas supply mode will be carried out simultaneously.

3. The method for merging and matching gas test items for LNG carriers according to claim 1, characterized in that, In step S2, after the 21st hour of the initial cooling of the cargo hold, the subsequent cargo hold cooling process is carried out simultaneously with the GMS control GCU flow test. During this stage, the amount of volatile gas formed in the initial cooling cargo hold can be completely consumed by the GCU combustion. It is necessary to cut off the natural gas replacement gas path between the initial cooling cargo hold and the non-initial cooling cargo hold.

4. The method for merging and matching gas test items for LNG carriers according to claim 1, characterized in that, When the maximum flow rate of the forced vaporizer is adjusted in step S3 and the endurance test of the compressor gas supply mode of the GCU is carried out simultaneously, the liquid supply pressure setting value of the gas pump in the cargo compartment should not be lower than the outlet pressure setting value of the LD compressor in the GCU. After the forced vaporizer flow rate is increased to more than 50%, the liquid supply pressure of the gas pump is gradually set to 120-130% of the outlet flow rate of the LD compressor, but not higher than the start-up setting value of the gas pipe safety valve, so as to ensure the increase of the outlet flow rate of the forced vaporizer.

5. The method for merging and matching gas test items for LNG carriers according to claim 1 or 4, characterized in that, When the maximum flow rate function of the forced vaporizer is adjusted in step S3 and the endurance test of the compressor air supply mode of the GCU is carried out simultaneously, the flow rate setting of the LD compressor air supply mode in the GCU must always be 5-8% higher than the outlet flow rate of the forced vaporizer. This ensures that the outlet flow rate of the forced vaporizer is always consumed by the GCU and steadily increases even when the ship's main engine is not running, and that the cargo tank pressure is always kept within a controllable range during this stage of the test.

6. The method for merging and matching LNG carrier gas test items according to claim 1 or 4, characterized in that, In step S3, when the maximum flow rate function of the forced vaporizer is adjusted and the endurance test of the compressor gas supply mode of the GCU is carried out simultaneously, after the GCU reaches the maximum flow rate in the LD compressor gas supply mode, the maximum combustion flow rate of the GCU is maintained and the OPV valve of the gas supply network is gradually opened manually. After each opening of the OPV valve, the outlet flow rate of the forced vaporizer is gradually increased. During the gradual opening of the OPV valve in the gas supply network, continuously monitor the condensate flow of the forced vaporizer and the LD heater in the GCU. If the condensate flow of the forced vaporizer and the LD heater in the GCU increases too much in a short period of time, the outlet flow of the forced vaporizer should be gradually reduced to keep the condensate flow controllable. Through this process, the maximum flow of the forced vaporizer can be achieved. When the maximum flow test of the forced vaporizer is completed, the various flow test conditions of the GCU in the LD compressor gas supply mode are also matched, and it is not necessary to consume natural gas specifically for the endurance test of the GCU in the compressor gas supply mode.

7. The method for merging and matching gas test items for LNG carriers according to claim 6, characterized in that, During the gradual opening of the OPV valve in the gas supply network, the OPV valve is opened by 1% each time to maintain stable pressure in the gas supply line and stable combustion in the GCU. After each opening of the OPV valve, the outlet flow rate of the forced vaporizer is gradually increased, with an increase of no more than 3%, and the OPV valve is opened again only after the pressure in the gas supply network has stabilized.

8. The method for merging and matching gas test items for LNG carriers according to claim 1, characterized in that, In step S4, when the energy consumption test of the main engine at different speeds and the gas management system (GMS) automatic control forced vaporizer flow test are carried out simultaneously in the unmanned engine room project under engine room gas mode, the 100% flow of the GCU is set to the rated maximum gas consumption of the main engine. The actual gas consumption of the main engine at different speeds is simulated by increasing or decreasing the gas flow of the GCU. The GCU transmits its gas flow to the ship's automated control system (IAS) in real time. The GMS automatically adjusts the outlet flow of the forced vaporizer according to the tank pressure change in the liquid cargo tank, and also adjusts the outlet flow of the gas pump simultaneously. When the main engine power increase / decrease test and the gas management system (GMS) automatic control forced vaporizer flow test are carried out simultaneously in the engine room gas mode unmanned engine room project, the 100% flow of the GCU is set to the rated maximum gas consumption of the main engine. The actual gas consumption of the main engine under different power is simulated by increasing or decreasing the gas flow of the GCU. The GCU transmits its gas flow to the ship's automated control system (IAS) in real time. The GMS automatically adjusts the outlet flow of the forced vaporizer according to the tank pressure change in the liquid cargo tank, and also adjusts the outlet flow of the gas pump in sync. During this step, only the gas pumps in the liquid cargo tanks are operated; the warm-up operations are carried out in the other non-liquid cargo tanks only after the liquid cargo tanks have completed partial unloading to the gas station.

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