A low-temperature test method for an enclosure system with device test function

Abstract

The application discloses a kind of low temperature test methods of enclosure system with equipment test function, which comprises the following steps: step 1, nitrogen is used to replace the air in the enclosure system, and the inertization of the enclosure system is completed;Step 2, liquefied natural gas is gasified by evaporator, and the nitrogen in the inertized enclosure system is replaced, the function of the evaporator gasification LNG is tested, and the function test of the gas delivery equipment and the dual fuel equipment is carried out;Step 3, the enclosure system is cooled by LNG, the internal temperature is reduced to meet the low temperature test condition, and the low temperature test and the low temperature spray system, the gas delivery equipment and the dual fuel equipment test;Step 4, when there are two enclosure systems, they are alternately inertized, replaced, cooled and cooled down;Step 5, the remaining enclosure system repeats the operation of step 4, and the cooling and cooling of the remaining enclosure system are completed.The test efficiency is greatly improved by ingenious planning of the test scheme, reasonable design of the test process and completion of the test of the related equipment.

Description

Technical Field

[0001] This invention belongs to the field of marine engineering equipment technology, and specifically relates to a low-temperature testing method for an enclosure system that also has equipment testing functions. Background Technology

[0002] Natural gas, with its clean, convenient, and high calorific value, is playing an increasingly important role in global energy consumption. The volume of liquefied natural gas is only about 1 / 600th that of gaseous natural gas, significantly reducing storage costs and space requirements. LNG storage has become the preferred method, and LNG is typically stored using specially designed cryogenic containment systems. To meet the growing market demand for natural gas, more and more ships and storage tanks for transporting LNG are being built, with the containment system for holding the LNG being the core component.

[0003] To ensure the safety of LNG transportation and storage, cryogenic testing is required after the containment system is constructed to verify its design and construction quality.

[0004] Current low-temperature testing methods for building envelopes, due to a lack of overall design and a complete system, inevitably release excessive amounts of natural gas during the entire testing process, causing certain damage to the environment. Alternatively, they may simply burn the excess natural gas, which is undoubtedly a waste of valuable resources. Summary of the Invention

[0005] In view of this, the present invention provides a low-temperature testing method for an enclosure system that also has equipment testing functions, in order to solve the problems existing in the above-mentioned background art.

[0006] A low-temperature testing method for an enclosure system that also functions as an equipment testing system includes the following steps:

[0007] The liquefied natural gas (LNG) ship is equipped with a containment system, evaporator, gas delivery equipment, dual-fuel equipment, cryogenic spray system, and gas heater. The cryogenic testing method for the containment system specifically includes the following steps:

[0008] Step 1: Evaporate liquid nitrogen through the evaporator to produce nitrogen gas. Use the nitrogen gas to replace the air in the enclosure system to complete the inerting of the enclosure system. During the inerting process, test the function of the evaporator in vaporizing liquid nitrogen.

[0009] Step 2: Gasify liquefied natural gas in an evaporator, use the gasified natural gas to replace the nitrogen in the inerted enclosure system, and complete the gas replacement of the enclosure system. The gas mixture containing natural gas is transported to the dual-fuel equipment for processing and utilization. Test the function of the evaporator in gasifying liquefied natural gas, and at the same time conduct functional tests on the gas transportation equipment and the dual-fuel equipment.

[0010] Step 3: Use liquefied natural gas to cool the enclosure system after gas replacement, gradually reduce the internal temperature of the enclosure system until the low temperature test conditions are met, and carry out the low temperature test of the enclosure system. The natural gas generated during the cooling process of the enclosure system is transported to the dual-fuel equipment for processing and utilization. During this process, functional tests are carried out on the low temperature spray system, gas transportation equipment and dual-fuel equipment.

[0011] Step 4: If there are two enclosure systems, the second enclosure system is inerted after step 1. The natural gas produced in step 3 is used as the replacement gas. After being heated by the gas heater, step 2 is repeated to complete the gas replacement of the second enclosure system. Step 3 is repeated to complete the cooling and temperature reduction of the second enclosure system.

[0012] Step 5: If there are multiple enclosure systems, repeat the operation of Step 4 for the remaining enclosure systems to complete the cooling and temperature reduction of the remaining enclosure systems, and complete the functional tests of the evaporator, gas delivery equipment, dual-fuel equipment, cryogenic spray system and gas heater.

[0013] Preferably, the enclosure system can be any type of enclosure system defined by the IGC specification, and the number can be one or more. The enclosure system is equipped with gas pipes, liquid pipes, and internal liquid pumps and internal sprinkler pipes.

[0014] Preferably, the evaporator is designed to operate at a temperature of -196°C or lower to meet the requirements for vaporizing liquid nitrogen, and is used to vaporize liquid nitrogen and liquefied natural gas in steps 1 and 2.

[0015] Preferably, during steps 1 and 2, the vaporization rate of the evaporator can be adjusted according to the different volumes and quantities of the enclosure system, thereby enabling functional testing of the evaporator.

[0016] Preferably, in step 2, as the replacement process proceeds, the natural gas content in the replaced gas continuously increases. The natural gas content in the replaced gas is measured by a fixed or handheld hydrocarbon analyzer, and the gas is then transported to different dual-fuel devices based on the natural gas content.

[0017] Preferably, in step 3, liquefied natural gas is atomized by a spray system and sprayed into the enclosure system. It absorbs heat and vaporizes within the enclosure system, thereby reducing the temperature of the enclosure system. The spray system is installed inside the enclosure system and consists of low-temperature pipelines and atomizing nozzles. The vaporized natural gas is transported to a dual-fuel equipment for processing and utilization through a gas conveying device.

[0018] Preferably, the gas conveying equipment can be a centrifugal, screw, or reciprocating compressor, and the dual-fuel equipment can be a dual-fuel generator, a dual-fuel boiler, or a natural gas combustion device, etc.

[0019] Preferably, in step 4, the gas replacement of the second enclosure system and the cold chamber operation of the first enclosure system are carried out simultaneously, and the replacement gas is the evaporation gas generated during the cold chamber process after being conditioned by a gas heater.

[0020] Preferably, in step 5, the LNG can be supplied by an external input or by a cargo pump within the first containment system.

[0021] Preferably, the liquefied natural gas can also be other cryogenic liquefied gases with fuel properties, and the test method can also be used for equipment testing and cryogenic testing of containment systems on liquefied gas transport ships.

[0022] The beneficial effects of this invention are:

[0023] The low-temperature testing method for building envelope systems, which combines equipment testing functions, is achieved through clever planning of the test scheme and reasonable design of the test process. It effectively utilizes the media introduced and extracted at each stage of the test, and combines the low-temperature testing process of the building envelope system with equipment testing. By completing the testing of relevant equipment at different stages of the low-temperature test, it greatly improves the test efficiency, has high economic efficiency, significantly reduces greenhouse gas emissions, and makes the test process greener and more environmentally friendly. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of the low-temperature testing method for the enclosure system that also has equipment testing functions according to the present invention.

[0026] Figure 2 This is a schematic diagram of the inerting principle of the enclosure system.

[0027] Figure 3 This is a schematic diagram of the gas replacement principle of a single enclosure system.

[0028] Figure 4 This is a schematic diagram of a single enclosure system for a cold compartment.

[0029] Figure 5 This is a schematic diagram of the dual enclosure system with cold compartment and gas replacement.

[0030] Figure 6 This is a schematic diagram of a multi-enclosure system for LNG transport, cold storage, and gas replacement.

[0031] The meanings of the equipment labels in the diagram are as follows:

[0032] 1 Evaporator; 2 High-load compressor; 3 Low-load compressor; 4 Ventilation mast; 5 Gas heater; 6 Heat exchanger; 7 Hydrogen analyzer; 8 Cryogenic cargo transfer pump; 9 In-cabin sprinkler system; 101 First enclosure system; 102 Second enclosure system; 103 Third enclosure system;

[0033] The pipe labels in the diagram mean:

[0034] C1 is the pipeline to the dual-fuel internal combustion engine; C2 is the pipeline to the dual-fuel boiler / natural gas combustion unit; C3 is the pipeline to the gas collection unit; 1-1 Nitrogen injection pipeline for inerting operation; 1-2 Air and nitrogen mixture discharge pipeline for inerting operation; 2-1 Natural gas injection pipeline for gas replacement operation; 2-2 Replacement gas to high-load compressor pipeline; 2-3 Replacement gas to low-load compressor pipeline; 2-4 Replacement gas to venting mast pipeline; 3-1 LNG spray pipeline; 3-2 Natural gas to low-load compressor pipeline; 4-1 LNG spray pipeline. 4-2 Gas replacement natural gas injection pipeline for the second enclosure system; 4-3 Excess natural gas to low-load compressor pipeline; 4-4 Replacement gas to venting mast pipeline; 4-5 Replacement gas to high-load compressor pipeline; 4-6 Replacement gas to low-load compressor pipeline; 5-1 LNG spray pipeline; 5-2 Natural gas to gas heater pipeline; 5-3 Excess natural gas to low-load compressor pipeline; 5-4 Replacement gas to venting mast pipeline; 5-5 Replacement gas to high-load compressor pipeline; 5-6 Replacement gas to low-load compressor pipeline. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] This invention provides a low-temperature testing method for building envelope systems that also functions as equipment testing. This method combines the low-temperature testing process of the building envelope system with equipment testing, and completes the testing of relevant equipment at different stages of the low-temperature testing.

[0037] like Figure 1 As shown, the low-temperature testing method for the enclosure system of the present invention specifically includes the following steps:

[0038] Step 1, as follows Figure 2As shown, liquid nitrogen evaporates in evaporator 1 to produce nitrogen gas. Taking advantage of nitrogen's lower density than air, nitrogen is injected into the enclosure system (101, 102, 103) from the top through injection pipe 1-1. The discharged gas is discharged through air-nitrogen mixture discharge pipe 1-2 and then through ventilated mast 4 until the enclosure system (101, 102, 103) reaches an inerted state. In this embodiment, during the inerting operation phase, the vaporization rate of evaporator 1 can be adjusted according to the different volumes and numbers of the enclosure system (101, 102, 103) to achieve a functional test of the vaporization of liquid nitrogen by evaporator 1.

[0039] Step 2, as follows Figure 3 As shown, liquefied natural gas (LNG) is vaporized in evaporator 1. The vaporized natural gas is injected into the first containment system 101 from the top through the gas replacement operation natural gas injection pipeline 2-1. The replaced gas is discharged through the bottom pipeline of the first containment system 101. The natural gas content in the replaced gas changes continuously as the replacement operation progresses. The specific content can be measured by a hydrocarbon analyzer 7. In this embodiment, the hydrocarbon analyzer 7 can be fixed or handheld.

[0040] In this embodiment, when the natural gas content in the gas being replaced is less than 5% by volume, it is called low-methane gas. The low-methane gas can be discharged to the atmosphere through the venting mast pipeline 2-4, or it can be pressurized through the low-load compressor pipeline 2-3, and then the temperature can be adjusted through the heat exchanger 6 before being transported to the dual-fuel boiler or natural gas combustion device for processing and utilization through pipeline C2.

[0041] In this embodiment, when the natural gas content in the gas being replaced is greater than or equal to 5% by volume, it is referred to as high-methane gas. The replaced high-methane gas is sent to the low-load compressor pipeline 2-3, where its temperature is regulated by the heat exchanger 6, and then transported via pipeline C2 to a dual-fuel boiler or natural gas combustion device for processing and utilization. As the replacement operation progresses, the natural gas content further increases to the methane count required by the dual-fuel internal combustion engine. The replaced gas then passes through pipeline 2-3, is pressurized and temperature-regulated by the low-load compressor 3 and the heat exchanger 6, and is then transported to the dual-fuel internal combustion engine via pipeline C1. For excess high-natural-gas-content replacement gas, it can be sent to the high-load compressor pipeline 2-2 and then via pipeline C3 to a gas collection device. The gas collection device may include a high-pressure gas booster and a high-pressure collector.

[0042] In this embodiment, the vaporization rate of evaporator 1 is adjusted according to the required amount of natural gas at different stages of the gas replacement operation, thereby achieving a functional test of LNG vaporization by evaporator 1. During the gas replacement process, the ratio of natural gas / nitrogen mixture changes continuously. Therefore, the operation of low-load compressor 3 and high-load compressor 2 under different gas compositions can be tested, as well as the function of heat exchanger 6 under different operating conditions. Simultaneously, the operation of dual-fuel boiler and natural gas combustion device under different methane contents, and the operation of dual-fuel generator under different natural gas contents and different loads can also be tested.

[0043] Step 3, as follows Figure 4 As shown, liquefied natural gas is transported to the spray system 9 through the LNG spray pipeline. After being atomized by the spray system 9, the LNG is sprayed into the first enclosure system 101 after replacement. The atomized LNG continuously absorbs heat, causing the temperature of the first enclosure system 101 to continuously decrease until the temperature of the first enclosure system 101 reaches the requirements of the low temperature test.

[0044] In this embodiment, atomized LNG absorbs heat and vaporizes to produce natural gas. Excess natural gas is transported to the low-load compressor 3 via the natural gas-to-low-load compressor pipeline 3-2 installed at the top of the first enclosure system 101. After being pressurized, the natural gas is conditioned by the heat exchanger 6 and then transported to the dual-fuel internal combustion engine via pipeline C1, or to the dual-fuel boiler and natural gas combustion device via C2 for utilization and consumption. During this process, the long-term operating performance of the low-load compressor 3 and the heat exchanger 6 can be tested, as well as the operating performance of the dual-fuel internal combustion engine, dual-fuel boiler, or natural gas combustion device.

[0045] Step 4, as follows Figure 5 As shown, the specific implementation method for low-temperature testing with two enclosure systems is as follows:

[0046] First, the second enclosure system 102 can complete the inerting operation simultaneously or sequentially with the first enclosure system 101 according to step 1.

[0047] Secondly, the first enclosure system 101 completes gas replacement in step 2; then, the cold chamber operation is performed in step 3. During the cold chamber operation of the first enclosure system 101:

[0048] On the one hand, the natural gas generated during the cold compartment operation is conditioned by the gas heater 5 and then injected into the second enclosure system 102 from the top through the gas replacement natural gas injection pipeline 4-2. The replaced gas is discharged through the bottom pipeline of the second enclosure system 102. The gas replaced by the second enclosure system 102 performs relevant operations according to step 2, completing the replacement operation of the second enclosure system 102 and the testing of related equipment.

[0049] On the other hand, the excess natural gas generated by the cold compartment of the first enclosure system 101 (i.e. the natural gas remaining during the gas replacement of the second enclosure system 102) is transported to the low-load compressor 3 through the excess natural gas to low-load compressor pipeline 4-3, and the gas replacement operation of the second enclosure system is completed according to step 3.

[0050] Finally, following step 3, complete the cold chamber operation of the second enclosure system 102 to bring the temperature up to the requirements of the low-temperature test.

[0051] Step 5, as follows Figure 6 As shown, the specific implementation method for low-temperature testing with multiple enclosure systems is as follows:

[0052] First, multiple enclosure systems (101, 102, 103) can complete the inerting operation simultaneously or sequentially according to step 1.

[0053] Next, repeat step 4 to complete the gas replacement of the cold compartment in the first containment system 101 and the second containment system 102. At this time, a certain amount of LNG can be stored in the first containment system 101. Using the cryogenic cargo transfer pump 8 installed in the first containment system 101, the LNG is transferred to the spray system 9 of the second containment system 102 through the spray pipeline 5-1. During this process, the operation of the cryogenic cargo transfer pump 8 at different liquid levels can be monitored.

[0054] Secondly, the natural gas generated during the cooling process of the second enclosure system 102 is heated by the gas heater 5 according to the relevant operation in step 4, and then introduced into the third enclosure system 103 through the remaining enclosure system gas replacement natural gas injection pipeline 5-2, thereby completing the gas replacement operation of the third enclosure system 103.

[0055] Finally, following step 3, complete the cold chamber operation of the third enclosure system 103 so that the temperature of all enclosure systems reaches the low-temperature test requirements.

[0056] In this embodiment, the containment system can be one of type A, type B, type C, or membrane type. The liquefied natural gas used here can also be other cryogenic liquefied gases with fuel properties. The cryogenic testing methods involved can also be used for equipment testing and cryogenic testing of containment systems on liquefied gas carriers.

[0057] In this embodiment, Figures 1-5 Although the names of the pipes in different diagrams are different, pipes with the same function can be regarded as the same pipe or have a common main pipe.

[0058] This invention, through ingenious planning of experimental schemes and rational design of experimental procedures, effectively utilizes the media introduced and extracted at each stage of the experiment, combines the low-temperature testing process of the building envelope with equipment testing, and completes the testing of relevant equipment at different stages of the low-temperature test, which greatly improves experimental efficiency, has high economic efficiency, significantly reduces greenhouse gas emissions, and makes the experimental process greener and more environmentally friendly.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cryogenic testing method for a containment system that also functions as equipment testing, wherein the liquefied natural gas (LNG) ship is equipped with a containment system, an evaporator, gas delivery equipment, a dual-fuel system, a cryogenic spray system, and a gas heater, characterized in that, The low-temperature testing method for this enclosure system specifically includes the following steps: Step 1: Evaporate liquid nitrogen through the evaporator to produce nitrogen gas. Use the nitrogen gas to replace the air in the enclosure system to complete the inerting of the enclosure system. During the inerting process, test the function of the evaporator in vaporizing liquid nitrogen. Step 2: Gasify liquefied natural gas in an evaporator, use the gasified natural gas to replace the nitrogen in the inerted enclosure system, and complete the gas replacement of the enclosure system. The gas mixture containing natural gas is transported to the dual-fuel equipment for processing and utilization. Test the function of the evaporator in gasifying liquefied natural gas, and at the same time conduct functional tests on the gas transportation equipment and the dual-fuel equipment. Step 3: Use liquefied natural gas to cool the enclosure system after gas replacement, gradually reduce the internal temperature of the enclosure system until the low temperature test conditions are met, and carry out the low temperature test of the enclosure system. The natural gas generated during the cooling process of the enclosure system is transported to the dual-fuel equipment for processing and utilization. During this process, functional tests are carried out on the low temperature spray system, gas transportation equipment and dual-fuel equipment. Step 4: If there are two enclosure systems, the second enclosure system is inerted after step 1. The natural gas produced in step 3 is used as the replacement gas. After being heated by the gas heater, step 2 is repeated to complete the gas replacement of the second enclosure system. Step 3 is repeated to complete the cooling and temperature reduction of the second enclosure system. Step 5: If there are multiple enclosure systems, repeat the operation of Step 4 for the remaining enclosure systems to complete the cooling and temperature reduction of the remaining enclosure systems, and complete the functional tests of the evaporator, gas delivery equipment, dual-fuel equipment, cryogenic spray system and gas heater.

2. The low-temperature testing method for an enclosure system that also functions as an equipment testing system according to claim 1, characterized in that, The enclosure system refers to various types of enclosure systems defined by the IGC specification, and may be single or multiple. The enclosure system is connected to gas pipes and liquid pipes, and a liquid pump and spray pipes are installed inside the enclosure system.

3. The low-temperature testing method for an enclosure system that also functions as an equipment testing system according to claim 1, characterized in that, The evaporator is designed to operate at a temperature of -196°C or below, which meets the requirements for vaporizing liquid nitrogen and is used for vaporizing liquid nitrogen and liquefied natural gas.

4. The low-temperature testing method for an enclosure system that also functions as an equipment testing system according to claim 3, characterized in that, In steps 1 and 2, the vaporization rate of the evaporator is adjusted according to the different volumes and quantities of the enclosure system, thereby realizing the functional test of the evaporator.

5. The low-temperature testing method for an enclosure system that also functions as an equipment testing system according to claim 1, characterized in that, In step 2, as the replacement process proceeds, the natural gas content in the replaced gas continuously increases. The natural gas content in the replacement gas is measured by a fixed or handheld hydrocarbon analyzer. Depending on the natural gas content, it is transported to different dual-fuel equipment for processing and utilization using a gas delivery device.

6. The low-temperature testing method for an enclosure system that also functions as an equipment testing system according to claim 1, characterized in that, In step 3, liquefied natural gas is atomized by a spray system and sprayed into the enclosure system. It absorbs heat and vaporizes within the enclosure system to reduce the temperature of the enclosure system. The spray system is installed inside the enclosure system and consists of low-temperature pipelines and atomizing nozzles. The vaporized natural gas is transported to a dual-fuel equipment for processing and utilization through a gas conveying device.

7. A low-temperature testing method for an enclosure system that also functions as an equipment testing system, as described in claim 5 or 6, characterized in that, The gas conveying equipment is a centrifugal, screw, or reciprocating compressor, and the dual-fuel equipment is a dual-fuel generator, a dual-fuel boiler, or a natural gas combustion device.

8. The low-temperature testing method for an enclosure system that also functions as an equipment testing system according to claim 1, characterized in that, In step 4, the gas replacement operation of the second enclosure system and the cold chamber operation of the first enclosure system are carried out simultaneously. The gas used for gas replacement is the evaporation gas generated during the cold chamber process after being conditioned by a gas heater.

9. A low-temperature testing method for an enclosure system that also functions as an equipment testing system, as described in claim 1, is characterized in that... In step 5, liquefied natural gas is either supplied from an external source or by a liquid cargo pump within the first containment system.

10. A low-temperature testing method for an enclosure system that also functions as an equipment testing system, as described in claim 1, characterized in that, The test method is used for equipment testing and low-temperature testing of containment systems on liquefied gas carriers; the containment system is one of type A, type B, type C or membrane type.

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