Marine double-compressor integrated BOG compression skid

Abstract

The utility model discloses a marine double-compressor integrated BOG compression skid which comprises an input pipeline, a BOG compression system, a lubricating oil system, a lubricating oil separator and an output pipeline, and the BOG compression system comprises a BOG heater and two sets of BOG compressors; the lubricating oil system comprises a lubricating oil filter and a lubricating oil pump, the input pipeline is sequentially connected with the BOG compression system and the lubricating oil separator, and the output pipeline is connected with the gas output end of the lubricating oil separator; one end of the lubricating oil filter is connected with the lubricating oil output end of the lubricating oil separator, and the other end of the lubricating oil filter is connected with the lubricating oil pump and then connected with the BOG compressor. A single heat exchange system is used, a double-compressor integration scheme is achieved, static equipment is shared, the occupied space of the equipment is reduced, meanwhile, economical efficiency is improved, and cost is reduced; the compressor is a double-screw compressor, the pressure range of compressed gas is wider, and the actual application requirement is met.

Description

Technical Field

[0001] The utility model relates to the technical field of marine gas supply, in particular to a dual-compressor integrated BOG compression skid for a ship. Background Art

[0002] NG (Natural Gas) is the abbreviation of natural gas. Its main components are alkanes, of which methane accounts for the vast majority, and there are also small amounts of ethane, propane and butane. LNG: Liquefied Natural Gas, is natural gas that has been compressed and cooled to its boiling point (-161.5 degrees Celsius) to become liquid. Usually, liquefied natural gas is stored in low-temperature storage tanks at -161.5 degrees Celsius and about 0.1MPa. Its main component is methane, which is transported by special ships or tank trucks and re-gasified when used. BOG: Boil Off Gas, is the gas produced by gasification due to heat conduction during the storage and transportation of liquefied natural gas (LNG), that is, boil-off gas or flash gas. The proportion of BOG is affected by many factors, including the design and performance of storage and transportation facilities, the quality of natural gas and the gasification rate. Under normal circumstances, the proportion of BOG in LNG storage and transportation is about 0.05%~0.5%.

[0003] The current shipping industry is in the early stages of transitioning to new energy sources. From the perspective of the application progress of different alternative fuels, LNG is currently the most widely used alternative fuel. Since LNG is volatile at low temperatures and produces BOG, in order to improve the navigation efficiency of ships, the traditional method is to set up an independent heat exchange system to handle the BOG that evaporates during the normal operation of the LNG fuel supply system, but the space occupied will increase accordingly, which is contrary to the compactness required for ship equipment installation.

[0004] The traditional method faces the following problems: 1. The space on the ship is limited. Most of the existing BOG compression systems adopt non-skid design. The testing and debugging of non-skid design must be carried out on-site, and the pipelines are complex, which cannot fully utilize the three-dimensional space, resulting in high difficulty, high cost and long time for installation. 2. Each system is scattered and large, and it is difficult to split and relocate for use. 3. The compression ratio of single-screw compressors is relatively low, which cannot be applied to high-pressure gas compression, and the actual scope of use is small. Summary of the invention

[0005] In view of the deficiencies in the prior art, the utility model provides a dual-compressor integrated BOG compression skid for ships, which adopts a skid design, reduces equipment area, and reduces installation difficulty and overall cost.

[0006] The technical scheme of the utility model is: a dual-compressor integrated BOG compression skid for ship, comprising an input pipeline, a BOG compression system, a lubricating oil system, a lubricating oil separator and an output pipeline, wherein the BOG compression system comprises a BOG heater and two sets of BOG compressors; the lubricating oil system comprises a lubricating oil filter and a lubricating oil pump, the input pipeline is connected to the BOG compression system and the lubricating oil separator in sequence, the output pipeline is connected to the gas output end of the lubricating oil separator, and the output pipeline is also connected to the LNG gas supply system; one end of the lubricating oil filter is connected to the lubricating oil output end of the lubricating oil separator, and the other end is connected to the lubricating oil pump and then connected to the BOG compressor; the BOG gas in the input pipeline forms high-temperature BOG gas after passing through the BOG heater, forms a gas mixed with high-temperature and high-pressure BOG and lubricating oil after passing through the BOG compressor, and separates NG gas and low-temperature lubricating oil after entering the lubricating oil separator, and the NG gas returns to the LNG gas supply system through the output pipeline, and the low-temperature lubricating oil enters the BOG compressor through the lubricating oil pump after being filtered by the lubricating oil filter and is sprayed and mixed with the BOG gas.

[0007] Preferably, each set of BOG compressor is also provided with a matching compressor motor to provide power for the BOG compressor, and the two sets of BOG compressors are connected in parallel to the pipeline.

[0008] As further preferred, the BOG compressor uses a twin-screw compressor.

[0009] Preferably, the BOG heater is a plate heater, including a high-temperature water-ethylene glycol input end and a low-temperature water-ethylene glycol output end. The high-temperature water-ethylene glycol flows into the BOG heater from the high-temperature water-ethylene glycol input end, exchanges heat energy with the low-temperature BOG gas in the input pipeline, and is converted into low-temperature water-ethylene glycol, which is output from the low-temperature water-ethylene glycol output end; at this time, the BOG gas is converted into high-temperature BOG gas and is input into the BOG compressor.

[0010] Preferably, the BOG compressor is provided with a lubricating oil spraying device. In the lubricating oil system, the lubricating oil passing through the lubricating oil pump is sprayed and mixed with the high-temperature BOG gas from the lubricating oil spraying device, and is pressurized by the BOG compressor to form a high-temperature and high-pressure BOG and lubricating oil mixed gas.

[0011] Preferably, the lubricating oil filter is a duplex lubricating oil filter connected between the lubricating oil separator and the lubricating oil pump, and the lubricating oil pump is also a duplex lubricating oil pump connected to the pipeline in parallel.

[0012] Preferably, a three-way valve is provided at the output end of the lubricating oil pump, one end of the three-way valve is connected to the output end of the lubricating oil pump, the second end is connected to the BOG compressor, specifically, the lubricating oil spraying device, and the third end is connected to the lubricating oil separator. The low-temperature lubricating oil separated by the lubricating oil separator is filtered by the lubricating oil filter and then transported by the lubricating oil pump to the spraying device at the input end of the BOG compressor. The flow rate is adjusted by the three-way valve to return the excess lubricating oil to the lubricating oil separator.

[0013] As further preferred, the lubricating oil separator further comprises a low-temperature water-ethylene glycol input end and a high-temperature water-ethylene glycol output end, the low-temperature water-ethylene glycol input end is connected to the low-temperature water-ethylene glycol output end of the BOG heater, and the high-temperature water-ethylene glycol output end is connected to the high-temperature water-ethylene glycol input end of the BOG heater; the low-temperature water-ethylene glycol input end flows the low-temperature water-ethylene glycol flowing from the low-temperature water-ethylene glycol output end of the BOG heater into the lubricating oil separator, exchanges heat energy with the high-temperature and high-pressure BOG and lubricating oil mixed gas, generates high-temperature water-ethylene glycol and low-temperature lubricating oil, the high-temperature water-ethylene glycol is output from the high-temperature water-ethylene glycol output end and sent to the BOG heater through a pipeline for recycling, and the low-temperature lubricating oil is sent to the lubricating oil filter for filtration.

[0014] Preferably, the gas output end of the lubricating oil separator is subsequently connected to an output pipeline.

[0015] Preferably, the BOG heater is provided with a boiler fuel output pipeline, and a portion of the high-temperature BOG gas generated after heat energy exchange by the BOG heater is directly output to the boiler through the boiler fuel output pipeline for use as fuel.

[0016] The beneficial effects of the utility model are as follows: the utility model preferentially uses a single heat exchange system to realize a dual compressor integration solution to share static equipment, thereby reducing the space occupied by equipment, while improving economy and reducing costs; the compressor uses a twin-screw compressor, and the compressed gas pressure range is wider, which meets the actual application requirements.

[0017] Compared with the prior art, the dual-compressor integrated BOG compression skid for ships provided by the utility model considers using a plate heat exchanger to exchange heat energy between high-temperature water-ethylene glycol and evaporated low-temperature BOG, and at the same time returns the lubricating oil produced by oil-gas separation to be sprayed and mixed with the low-temperature BOG in the pipeline between the lubricating oil filter and the BOG compressor, so that the mixed gas meets the inlet pressure and inlet temperature of the BOG compressor. This has the following benefits: 1. In the dual compressor integration solution, the lubricating oil in the lubricating oil system can realize heat energy recycling and reuse, improve the system operation efficiency, and increase the system operation flexibility; 2. After using the dual compressor integration solution, the BOG compression system and the lubricating oil system are integrated into one skid, the physical distance is reduced, and unnecessary heat energy consumption caused by pipeline transportation during system operation is avoided, and the operation cost is reduced. A single heat exchange system can meet the ship's heat exchange needs, reducing the space occupied by the equipment, while reducing the design cost and obtaining higher economy; 3. The use of twin-screw compressors is more energy-efficient than single-screw compressors in terms of the principle of use. During use, the volumetric efficiency is improved, the gas compression range is wider, the bearing load is reduced, the main engine life is increased, and the overall energy consumption and maintenance costs are lower. 4. The skid can be installed and tested in a more complete and advanced internal field, with more technicians participating. The prefabricated skid has an interface that can be directly connected to the on-site pipeline, effectively reducing the installation difficulty, installation cycle and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a pipeline connection relationship diagram of the utility model.

[0019] Description of labels:

[0020] 1: Input pipeline; 2: BOG heater; 2-1: High-temperature water-ethylene glycol input end; 2-2: Low-temperature water-ethylene glycol output end; 3: Boiler fuel output pipeline; 4: BOG compressor; 4-1: Compressor motor; 5: Lubricating oil separator; 5-1: Low-temperature water-ethylene glycol input end; 5-2: High-temperature water-ethylene glycol output end; 6: Lubricating oil filter; 7: Lubricating oil pump; 8: Three-way valve; 9: Output pipeline. DETAILED DESCRIPTION

[0021] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0022] like Figure 1As shown, the utility model comprises an input pipeline 1, a BOG compression system, a lubricating oil system, a lubricating oil separator 5 and an output pipeline 9. The BOG compression system comprises a BOG heater 2 and two sets of BOG compressors 4; the lubricating oil system comprises a lubricating oil filter 6 and a lubricating oil pump 7; the input pipeline 1 is connected to the BOG compression system and the lubricating oil separator 5 in sequence, and the output pipeline 9 is connected to the gas output end of the lubricating oil separator 5; one end of the lubricating oil filter 6 is connected to the lubricating oil output end of the lubricating oil separator 5, and the other end is connected to the lubricating oil pump 7 and then connected to the BOG compressor 4; the BOG gas in the input pipeline 1 forms high-temperature BOG gas after passing through the BOG heater 2, forms a gas mixed with high-temperature and high-pressure BOG and lubricating oil after passing through the BOG compressor 4, and separates NG gas and low-temperature lubricating oil after entering the lubricating oil separator 5, and the NG gas returns to the LNG gas supply system through the output pipeline 9, and the low-temperature lubricating oil enters the BOG compressor 4 through the lubricating oil pump 7 after being filtered by the lubricating oil filter 6 and sprayed and mixed with the BOG gas.

[0023] In this embodiment, each set of BOG compressor 4 is also provided with a matching compressor motor 4-1 to provide power for the BOG compressor 4, and the two sets of BOG compressors 4 are connected to the pipeline in parallel. The dual compressor integration solution is realized to share static equipment, which reduces the space occupied by the equipment, improves economy and reduces costs. In addition, the setting of the dual compressors can effectively prevent the situation where the entire skid cannot operate normally once the BOG compressor 4 is damaged, and one can work while the other is shut down for maintenance.

[0024] In this embodiment, the BOG compressor 4 uses a twin-screw compressor. The use of a twin-screw compressor is more energy-efficient than a single-screw compressor in terms of the principle of use. During use, the volumetric efficiency is improved, the gas compression range is wider, the bearing load is reduced, the service life of the main engine is increased, and the overall energy consumption and maintenance costs are lower.

[0025] In this embodiment, the BOG heater 2 is a plate heater, including a high-temperature water-ethylene glycol input end 2-1 and a low-temperature water-ethylene glycol output end 2-2. The high-temperature water-ethylene glycol flows into the BOG heater 2 from the high-temperature water-ethylene glycol input end 2-1, exchanges heat energy with the low-temperature BOG gas in the input pipeline 1, and is converted into low-temperature water-ethylene glycol, which is output from the low-temperature water-ethylene glycol output end 2-2; at this time, the BOG gas is converted into high-temperature BOG gas and is input into the BOG compressor 4.

[0026] In this embodiment, the BOG compressor 4 is provided with a lubricating oil spraying device. In the lubricating oil system, the lubricating oil passing through the lubricating oil pump 7 is sprayed and mixed with the high-temperature BOG gas from the lubricating oil spraying device, and is pressurized by the BOG compressor 4 to form a high-temperature and high-pressure BOG and lubricating oil mixed gas.

[0027] In this embodiment, the lubricating oil filter 6 is a double lubricating oil filter connected between the lubricating oil separator 5 and the lubricating oil pump 7. The lubricating oil pump 7 is also a double lubricating oil pump connected to the pipeline in parallel. The double filter and the double lubricating oil pump are in operation, one is in operation and the other is in standby, in order to prevent the whole system from being unable to work normally due to a sudden failure of the filter or the lubricating oil pump, and also for the purpose of facilitating maintenance.

[0028] In this embodiment, a three-way valve 8 is provided at the output end of the lubricating oil pump 7, one end of the three-way valve 8 is connected to the output end of the lubricating oil pump 7, the second end is connected to the BOG compressor 4, specifically, the lubricating oil spraying device, and the third end is connected to the lubricating oil separator 5. The low-temperature lubricating oil separated by the lubricating oil separator 5 is filtered by the lubricating oil filter 6 and then transported by the lubricating oil pump 7 to the spraying device at the input end of the BOG compressor 4. The flow rate is adjusted by the three-way valve 8 to return the excess lubricating oil to the lubricating oil separator 5.

[0029] In this embodiment, the lubricating oil separator 5 further comprises a low-temperature water-glycol input end 5-1 and a high-temperature water-glycol output end 5-2, wherein the low-temperature water-glycol input end 5-1 is connected to the low-temperature water-glycol output end 2-2 of the BOG heater 2, and the high-temperature water-glycol output end 5-2 is connected to the high-temperature water-glycol input end 2-1 of the BOG heater 2; the low-temperature water-glycol input end 5-1 flows the low-temperature water-glycol flowing from the low-temperature water-glycol output end 2-2 of the BOG heater 2 into the lubricating oil separator 5, and exchanges heat energy with the high-temperature and high-pressure BOG and lubricating oil mixed gas to generate high-temperature water-glycol and low-temperature lubricating oil, and the high-temperature water-glycol is output from the high-temperature water-glycol output end 5-2 and sent to the BOG heater 2 through the pipeline for recycling, and the low-temperature lubricating oil is sent to the lubricating oil filter 6 for filtration. The lubricating oil in the lubricating oil system can realize heat energy recycling, improve the system operation efficiency, and increase the system operation flexibility.

[0030] In this embodiment, the gas output end of the lubricating oil separator 5 is subsequently connected to an output pipeline 9. The output pipeline 9 is also connected to a lubricating oil filter and a BOG cooler (these two devices are not in the skid of the utility model, so Figure 1 There is no mark in the figure), the lubricating oil filter filters the output NG gas to ensure that the NG gas is completely separated from the lubricating oil before returning to the LNG gas supply system. The BOG cooler performs a heat exchange on the output NG gas, reduces the temperature of the NG gas, and then circulates it into the LNG gas supply system, because the NG gas entering the LNG gas supply system has temperature requirements and needs to be cooled.

[0031] In this embodiment, the BOG heater 2 is provided with a boiler fuel output pipeline 3, and a part of the high-temperature BOG gas generated after heat energy exchange by the BOG heater 2 is directly output to the boiler through the boiler fuel output pipeline 3 for use as fuel.

[0032] The working principle of the whole device is as follows: the BOG gas in the input pipeline 1 passes through the BOG heater 2, and the high-temperature water-ethylene glycol flowing into the high-temperature water-ethylene glycol input end 2-1 exchanges heat with it to form high-temperature BOG gas. A part of the high-temperature BOG gas is directly output to the boiler through the boiler fuel output pipeline 3 for use as fuel. The remaining high-temperature BOG gas is sprayed with mixed lubricating oil by the lubricating oil spraying device before entering the BOG compressor 4, and forms a gas mixed with high-temperature and high-pressure BOG and lubricating oil after passing through the BOG compressor 4. After entering the lubricating oil separator 5, NG gas and low-temperature lubricating oil are separated. The NG gas passes through the lubricating oil filter and BOG cooler connected to the output pipeline 9. The lubricating oil filter filters the output NG gas to ensure that the NG gas is completely separated from the lubricating oil before returning to the LNG gas supply system. The BOG cooler performs a heat exchange on the output NG gas, reduces the temperature of the NG gas, and then circulates it into the LNG gas supply system. Because the NG gas entering the LNG gas supply system has temperature requirements, it needs to be cooled. The low-temperature lubricating oil separated by the lubricating oil separator 5 is filtered by the lubricating oil filter 6 and then transported by the lubricating oil pump 7 to the spraying device at the input end of the BOG compressor 4 to be sprayed and mixed with the BOG gas. The flow rate is adjusted by the three-way valve 8 to return the excess lubricating oil to the lubricating oil separator 5. The low-temperature water-ethylene glycol input end 5-1 of the lubricating oil separator 5 allows the low-temperature water-ethylene glycol flowing from the low-temperature water-ethylene glycol output end 2-2 of the BOG heater 2 to flow into the lubricating oil separator 5, and heat energy is exchanged with the high-temperature and high-pressure BOG and lubricating oil mixed gas to generate high-temperature water-ethylene glycol and low-temperature lubricating oil. The high-temperature water-ethylene glycol is output from the high-temperature water-ethylene glycol output end 5-2 and sent to the BOG heater 2 through the pipeline for recycling, and the low-temperature lubricating oil is sent to the lubricating oil filter 6 for filtration.

[0033] In the description of the utility model specification, it is necessary to understand that the orientations or positional relationships indicated by the terms "one end", "the other end", "input end", "output end", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model.

[0034] In the present invention, unless otherwise specified and limited, the term "connection" and other terms should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A dual compressor integrated BOG compression skid for ships, characterized in that The invention comprises an input pipeline (1), a BOG compression system, a lubricating oil system, a lubricating oil separator (5) and an output pipeline (9). The BOG compression system comprises a BOG heater (2) and two sets of BOG compressors (4). The lubricating oil system comprises a lubricating oil filter (6) and a lubricating oil pump (7). The input pipeline (1) is connected to the BOG compression system and the lubricating oil separator (5) in sequence. The output pipeline (9) is connected to the gas output end of the lubricating oil separator (5). The output pipeline (9) is also connected to the LNG gas supply system. One end of the lubricating oil filter (6) is connected to the lubricating oil output end of the lubricating oil separator (5), and the other end is connected to the lubricating oil pump (7) and then connected to the BOG compressor (4).

2. A dual compressor integrated BOG compression skid for ships according to claim 1, characterized in that Each set of BOG compressors (4) is also provided with a matching compressor motor (4-1) for providing power to the BOG compressor (4), and the two sets of BOG compressors (4) are connected in parallel to the pipeline.

3. A dual compressor integrated BOG compression skid for ships according to claim 2, characterized in that The BOG compressor (4) is a twin-screw compressor.

4. The dual compressor integrated BOG compression skid for ships according to claim 1, characterized in that The BOG heater (2) is a plate-type heater, comprising a high-temperature water-ethylene glycol input end (2-1) and a low-temperature water-ethylene glycol output end (2-2). The high-temperature water-ethylene glycol flows into the BOG heater (2) from the high-temperature water-ethylene glycol input end (2-1), exchanges heat energy with the low-temperature BOG gas in the input pipeline (1), and is converted into low-temperature water-ethylene glycol, which is output from the low-temperature water-ethylene glycol output end (2-2).

5. The dual compressor integrated BOG compression skid for ships according to claim 1, characterized in that The BOG compressor (4) is provided with a lubricating oil spraying device. In the lubricating oil system, the lubricating oil passing through the lubricating oil pump (7) is sprayed and mixed with the high-temperature BOG gas from the lubricating oil spraying device, and is pressurized by the BOG compressor (4) to form a high-temperature and high-pressure BOG and lubricating oil mixed gas.

6. The dual compressor integrated BOG compression skid for ships according to claim 1, characterized in that The lubricating oil filter (6) is a duplex lubricating oil filter connected between the lubricating oil separator (5) and the lubricating oil pump (7); the lubricating oil pump (7) is also a duplex lubricating oil pump connected to the pipeline in parallel.

7. The dual compressor integrated BOG compression skid for ships according to claim 1, characterized in that The output end of the lubricating oil pump (7) is provided with a three-way valve (8), one end of the three-way valve (8) is connected to the output end of the lubricating oil pump (7), the second end is connected to the BOG compressor (4), specifically, the lubricating oil spraying device, and the third end is connected to the lubricating oil separator (5).

8. The dual compressor integrated BOG compression skid for ships according to claim 4, characterized in that The lubricating oil separator (5) further comprises a low-temperature water-ethylene glycol input end (5-1) and a high-temperature water-ethylene glycol output end (5-2), wherein the low-temperature water-ethylene glycol input end (5-1) is connected to the low-temperature water-ethylene glycol output end (2-2) of the BOG heater (2), and the high-temperature water-ethylene glycol output end (5-2) is connected to the high-temperature water-ethylene glycol input end (2-1) of the BOG heater (2).

9. A dual compressor integrated BOG compression skid for ships according to claim 1 or 7, characterized in that The gas output end of the lubricating oil separator (5) is subsequently connected to an output pipeline (9).

10. The dual compressor integrated BOG compression skid for ships according to claim 1, characterized in that The BOG heater (2) is provided with a boiler fuel output pipeline (3), and a portion of high-temperature BOG gas generated after heat energy exchange by the BOG heater (2) is directly output through the boiler fuel output pipeline (3) to the boiler for use as fuel.

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