EP4227620A1 - Method and device for reliquifying and returning vapour gas to an lng tank - Google Patents
Method and device for reliquifying and returning vapour gas to an lng tank Download PDFInfo
- Publication number
- EP4227620A1 EP4227620A1 EP22156041.0A EP22156041A EP4227620A1 EP 4227620 A1 EP4227620 A1 EP 4227620A1 EP 22156041 A EP22156041 A EP 22156041A EP 4227620 A1 EP4227620 A1 EP 4227620A1
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- EP
- European Patent Office
- Prior art keywords
- gas
- pressure
- bar
- bog
- lng tank
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 238000000034 method Methods 0.000 title claims abstract description 19
- 239000007789 gas Substances 0.000 claims abstract description 128
- 239000003949 liquefied natural gas Substances 0.000 claims abstract description 63
- 238000001816 cooling Methods 0.000 claims abstract description 41
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 18
- 238000007906 compression Methods 0.000 claims description 44
- 230000006835 compression Effects 0.000 claims description 44
- 238000002347 injection Methods 0.000 claims description 17
- 239000007924 injection Substances 0.000 claims description 17
- 239000007788 liquid Substances 0.000 claims description 15
- 239000000446 fuel Substances 0.000 claims description 14
- 239000002826 coolant Substances 0.000 claims description 10
- 239000012530 fluid Substances 0.000 claims description 8
- 239000012809 cooling fluid Substances 0.000 claims description 6
- 230000001105 regulatory effect Effects 0.000 claims description 6
- 238000002485 combustion reaction Methods 0.000 claims description 4
- 239000002737 fuel gas Substances 0.000 claims description 4
- 238000004064 recycling Methods 0.000 claims description 4
- 238000011144 upstream manufacturing Methods 0.000 claims description 2
- 238000005070 sampling Methods 0.000 claims 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 20
- 239000003345 natural gas Substances 0.000 description 9
- 239000000314 lubricant Substances 0.000 description 5
- 239000003507 refrigerant Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000000605 extraction Methods 0.000 description 2
- FGUUSXIOTUKUDN-IBGZPJMESA-N C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 Chemical compound C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 FGUUSXIOTUKUDN-IBGZPJMESA-N 0.000 description 1
- 239000000809 air pollutant Substances 0.000 description 1
- 231100001243 air pollutant Toxicity 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000000110 cooling liquid Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 230000003134 recirculating effect Effects 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/0002—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the fluid to be liquefied
- F25J1/0022—Hydrocarbons, e.g. natural gas
- F25J1/0025—Boil-off gases "BOG" from storages
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
- F25J1/0032—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration"
- F25J1/004—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by flash gas recovery
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
- F25J1/0201—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using only internal refrigeration means, i.e. without external refrigeration
- F25J1/0202—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process using only internal refrigeration means, i.e. without external refrigeration in a quasi-closed internal refrigeration loop
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
- F25J1/0228—Coupling of the liquefaction unit to other units or processes, so-called integrated processes
- F25J1/0229—Integration with a unit for using hydrocarbons, e.g. consuming hydrocarbons as feed stock
- F25J1/023—Integration with a unit for using hydrocarbons, e.g. consuming hydrocarbons as feed stock for the combustion as fuels, i.e. integration with the fuel gas system
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
- F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
- F25J1/0244—Operation; Control and regulation; Instrumentation
- F25J1/0245—Different modes, i.e. 'runs', of operation; Process control
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
- F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
- F25J1/0257—Construction and layout of liquefaction equipments, e.g. valves, machines
- F25J1/0275—Construction and layout of liquefaction equipments, e.g. valves, machines adapted for special use of the liquefaction unit, e.g. portable or transportable devices
- F25J1/0277—Offshore use, e.g. during shipping
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
- F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
- F25J1/0279—Compression of refrigerant or internal recycle fluid, e.g. kind of compressor, accumulator, suction drum etc.
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
- F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
- F25J1/0279—Compression of refrigerant or internal recycle fluid, e.g. kind of compressor, accumulator, suction drum etc.
- F25J1/0298—Safety aspects and control of the refrigerant compression system, e.g. anti-surge control
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2240/00—Processes or apparatus involving steps for expanding of process streams
- F25J2240/40—Expansion without extracting work, i.e. isenthalpic throttling, e.g. JT valve, regulating valve or venturi, or isentropic nozzle, e.g. Laval
Definitions
- the invention relates to the technical field of re-liquefaction of boil-off gas (BOG) from a liquefied natural gas (LNG) tank.
- BOG boil-off gas
- LNG liquefied natural gas
- LPG liquefied natural gas
- LNG liquefied natural gas
- LNG is a colorless and transparent liquid obtained by cooling natural gas, which consists mainly of methane, to around -163°C.
- natural gas which consists mainly of methane
- LNG can easily vaporize with a slight rise in temperature.
- LNG is therefore continuously vaporized naturally, thereby generating boil off gas (BOG).
- BOG means a loss of stored LNG and thus reduces transport efficiency on an LNG tanker, for example.
- BOG accumulates in a storage tank, there is a risk that the pressure in the storage tank will rise and the tank will be damaged.
- BOG is re-liquefied to be returned to an LNG storage tank
- BOG is used as an energy source combustion engine, such as a marine engine
- it is proposed to feed BOG from an LNG tank to a DFDE engine, an X-DF engine or a ME-GI marine engine.
- BOG is envisaged to use BOG as a refrigerant to reliquefy compressed BOG in a partial reliquefaction system (PRS).
- PRS partial reliquefaction system
- the system mentioned has the disadvantage that only a limited amount of BOG is available as a refrigerant and therefore only insufficiently low temperatures are reached when there is a high need for recondensation. This allows only a small portion of the BOG to be effectively reliquefied. A significant part of the compressed and cooled gas is re-introduced into the reliquefaction cycle in gaseous form and the system proves to be inefficient.
- PRS partial reliquefaction system
- the object is achieved by a method having the features of claim 1, or a device having the features of claim 5.
- This method is based on the idea that the coolant used to reliquefy the BOG in step e) is only available to a limited extent and/or should be used sparingly. In the case of a separate cooling circuit with a corresponding refrigerant, typically N 2 , cooling costs energy. If BOG from the LNG tank is used as the coolant instead, a low flow rate is desirable from a storage/transport efficiency perspective, particularly if an engine does not need to be run on the natural gas fuel at the same time, or if the engine (temporarily) only has one has low fuel requirements. In contrast to this, however, the cooling liquid for cooling the compressed gas to ambient temperature, in particular water, is available in practically unlimited quantities.
- step e) which has a low level of heat. This can be achieved by compressing the gas to a comparatively high pressure p high and cooling it by water cooling at this high pressure. If then in step d) the gas is at least partially expanded isoenthalpic before it is fed to the cooling in step e), a higher proportion of gas can be reliquefied with the available cooling capacity than if without step d) or starting from a lower pressure (for example 150 bar) would be reliquefied.
- Preferred is a method for supplying a high-pressure gas-injected engine with gas stored in an LNG tank partially as boil-off gas (BOG, F2) and for reliquefying and recycling BOG, comprising the steps according to claim 1, wherein in step d) at least a first part of the gas from step c) to the extent of the fuel requirements of a high-pressure gas-injected engine is supplied via an outlet to the high-pressure gas-injected engine and at least a second part of the gas from step c) is expanded to the pressure p expand .
- step d) at least a first part of the gas from step c) to the extent of the fuel requirements of a high-pressure gas-injected engine is supplied via an outlet to the high-pressure gas-injected engine and at least a second part of the gas from step c) is expanded to the pressure p expand .
- the highly compressed gas at pressure p high can either be used to power a high pressure gas injected engine or reliquefied.
- Natural gas is the fuel of choice, particularly on an LNG tanker, in order to limit the emission of air pollutants to a relatively low level.
- the adjustability of the amount that is fed to the gas injection engine or into the PRS allows flexible consideration of the climatic and meteorological conditions as well as the fuel requirements of the high-pressure gas injection engine.
- step b1 it is possible to adjust the operating mode. It has been found that at a low recondensation rate it can be efficient to simply compress to a lower pressure p low (step b1), because the BOG provides sufficient cooling capacity to cool the gas stream to be liquefied to a sufficiently low temperature level. On the other hand, compression to a high pressure at a high liquefaction rate proves to be more efficient because the additional cooling due to the expansion of the gas to be liquefied from p high to p low contributes to a higher re-liquefaction rate and thus to a more efficient overall system.
- a method is particularly preferred in which in step 0) in operating mode i) a target value p high in the range from 200 to 300 bar is selected and/or in operating mode ii) a target value p low in the range from 100 to 199 bar is selected. Thanks to the stepless adjustability between 100 and 300 bar that is available in this way, it is possible to gain even more flexibility in the recondensation cycle.
- a gas is provided for the cooling step in the indirect heat exchanger, which has a low level of heat. This is achieved by compressing the gas to a comparatively high pressure p high and cooling it with water at this high pressure. If then in step d) the gas at least is partially isenthalpic expanded before it is fed to the cooling in the heat exchanger, a higher proportion of gas can be reliquefied with the available cooling capacity than if without the cooling step preceding expansion, i.e. starting from a gas compressed only to a lower pressure (e.g. 150 bar). , cooled and reliquefied.
- a gas is provided for the cooling step in the indirect heat exchanger, which has a low level of heat. This is achieved by compressing the gas to a comparatively high pressure p high and cooling it with water at this high pressure. If then in step d) the gas at least is partially isenthalpic expanded before it is fed to the cooling in the heat exchanger, a higher proportion of gas can be reliquefied with the available cooling capacity than
- An advantage associated with the device is the efficiency gain at high flow rate of BOG, as described above at the process level.
- Another constructive advantage can be seen in the fact that the pressure in the intermediate stage(s) does not have to be checked before the last compression stage. For example, if some of the gas were to be withdrawn and fed to the PRS through a branch line following an intermediate stage (e.g., at p low ), the pressure after that intermediate stage would typically need to be regulated with a pressure control valve (PCV). On the other hand, if the entire conveyed BOG amount is uniformly compressed to the pressure p high , a single PCV suffices, which reduces the cost of the device.
- PCV pressure control valve
- the highly compressed gas at pressure p high can be optionally reliquefied or used to drive a high pressure gas injection engine.
- the adjustability of the quantity fed to the gas-injection engine or into the PRS allows the climatic and meteorological conditions as well as the fuel requirements of the high-pressure gas-injection engine (e.g. driving speed) to be flexibly taken into account.
- the gas Due to the renewed expansion in the second expansion unit (e.g. expansion valve, expander), the gas is cooled again by Joule-Thomsen expansion.
- the gaseous component separated by the gas-liquid separator can then be combined with the BOG taken from the storage tank and fed to the heat exchanger as coolant.
- the liquid component is fed into the storage tank. Thanks to the arrangement described, a higher relative proportion of the BOG can preferably be reliquefied with the same amount of coolant available.
- the first cooler is a water cooler, preferably water from the ship's cooling water system is used as coolant, so that the compressed gas can be cooled to a temperature of 35 to 45°C. Water is plentiful, especially when the device is used on a ship. Due to the cooling to the achievable temperature of 35 to 45° C. based on gas having a particularly high pressure, a lower enthalpy results already after the first cooling step compared to processes based on lower pressures.
- the multi-stage compressor arrangement has a first compression stage, the first compression stage being set up to compress BOG (F2) from the LNG tank to a first pressure p1 between 6 and 18 bar, and the first compression stage having at least one labyrinth has sealed piston compressors.
- BOG BOG
- the first compression stage has at least one labyrinth-sealed piston compressor, preferably comprises exclusively labyrinth-sealed piston compressors
- the first compression stage can have little or no lubricant operate.
- this has the advantage that the quality of the compressed gas is not impaired by contamination with lubricant.
- the danger that at the low temperatures of the BOG in low compression stages the lubricant (typically oil) solidifies and promotes wear of the machine parts can be avoided.
- the multi-stage compressor arrangement of the device has a middle and a last compression stage, which are set up to compress pre-compressed gas from a first pressure p1 to pressure p high , preferably optionally to pressure p high or pressure p low , wherein the last compression stage has a bypass with a controllable valve in order to control the return flow and thus the delivery pressure after the last compression stage, wherein gas can be fed back via the bypass in such a way that the gas at the outlet has the specified target pressure value p high , preferably the specified target pressure value pressure p high or p low .
- Such a device has the advantages already mentioned above that the efficiency of the reliquefaction can be improved for high gas conveying rates and the size of the device elements can be reduced. If the multi-stage compressor arrangement can now be operated variably thanks to the bypass with a controllable valve, or as a result a variable pressure between p low and p high can be provided at the gas outlet, further advantages result.
- the multi-stage compressor arrangement can be set up such that the side stream for recondensation at low recondensation rates is compressed only to p low , which is more efficient for small recondensation rates.
- the life expectancy of the devices can be improved when they are operated at only 50% of the nominal pressure for a significant part of the operating time.
- bypass can be regulated with a controllable valve in such a way that any desired pressure can be set between 100 and 300 bar. This allows the user additional flexibility to accommodate climatic and meteorological conditions as well as fuel requirements of the engine(s).
- the final compression stage comprises at least one piston ring sealed reciprocating compressor, preferably two piston ring sealed reciprocating compressors.
- Piston compressors sealed with piston rings, preferably lubricated, enable the gas to be compressed to a pressure in the range of p high .
- the device as described above may further comprise a branch line which is fluid-conducting downstream of the first compression stage and which further downstream opens into a supply line for a low-pressure gas-injected engine and/or a gas combustion unit.
- an engine operating at low pressure such as an X-DF engine
- p 1 an engine operating at low pressure
- X-DF engine can be supplied with fuel that is extracted after the first stage of compression.
- the first compression stage is sealed with little or no lubricant, because high quality fuel can then be supplied to the low-pressure gas-injected engine and/or the gas-combustion unit.
- the invention relates to the use of the device as described above on a ship, for example a natural gas tanker, in particular a ship which is propelled by means of a high-pressure gas-injection engine.
- a ship for example a natural gas tanker, in particular a ship which is propelled by means of a high-pressure gas-injection engine.
- figure 1 shows schematically a fuel gas supply system according to the present invention with a device for re-liquefying and returning exhaust gas (BOG) to a liquefied natural gas (LNG) tank 3
- Heat exchanger 20 fed to be used in indirect heat exchange as cooling fluid and then to be compressed by a multi-stage compressor assembly 10 to a high pressure p high of typically about 300 bar.
- the multi-stage compressor arrangement 10 comprises a first compression stage with piston compressors 71 and 72 and associated coolers, a middle compression stage with piston compressor 73 and associated cooler, and a final compression stage with reciprocating compressors 74 and 75 and associated coolers.
- the first compression stage 71, 72 is set up to compress the BOG to a pressure p1 of typically 7 bar. A portion of the BOG compressed in this way, preferably compressed without lubricant, can be fed to the low-pressure gas-injection engine 4 via the branch line 6 if required.
- the first compression stage can be pressure-controlled by means of a bypass having a pressure control valve (not shown).
- the multi-stage compressor assembly 10 is fluidly connected downstream to a first water cooler 50, thereby cooling the compressed gas to typically 40°C.
- the outlet pressure of the highest compression stage consisting here of piston compressors 75 and 74 and associated water coolers, is regulated via a bypass 19 with a pressure control valve 9 .
- the compressed BOG can either be fed via the outlet 7 to a high-pressure gas injection engine 2 as fuel or via the return line 8 to a first expansion unit 60, for example an expansion valve or an expander.
- excess BOG in excess of engine 2 fuel requirements is returned to recycle line 8 .
- the gas is expanded in the first expansion unit 60 to a pressure p ex-pand of approximately 150 bar. Due to the isenthalpic pressure reduction, the compressed natural gas is cooled again and can therefore be cooled further from about 20° C. in indirect heat exchange with the BOG (F2) from the LNG tank 3 in the heat exchanger 20 .
- the compressed by the compressor arrangement and cooled by water cooling 50, expansion 60 and heat exchanger 20 BOG is expanded again in a second expansion unit 30, now on a pressure p knock-out drum of typically 1 bar, and finally separated by a gas/liquid separator 40 into a liquid component and a gaseous component.
- the liquid component separated by the gas/liquid separator 40 is fed back to the LNG tank, and the gaseous component separated by the gas/liquid separator is combined with the BOG exiting the LNG tank in the extraction line 5 and then the heat exchanger 20 to be used as cooling fluid.
- natural gas reliquefaction is performed using BOG withdrawn from the storage tank as the refrigerant without the need for a separate BOG reliquefaction cycle.
- the present invention is not limited thereto and a separate refrigeration circuit can be arranged to ensure re-liquefaction of the entire BOG if required. Such a separate loop can ensure reliquefaction of the BOG, but requires separate equipment or an additional power source.
- figure 2 shows the compression and cooling circuit in a schematic Mollier diagram with dashed lines.
- the BOG In the initial state, the BOG is to the right of the dew line at an atmospheric pressure of 1 bar and approx. -160°C.
- the BOG heats up to ambient temperature or higher, approx. T1.
- step b) the compression to p high follows, for example in accordance with in figure 1 shown compressor arrangement over five piston compressors. This can be used as the first compression stage 101, middle compression stage 102, and last compression stage 103 can be arranged, each with subsequent water cooling to the temperature T 1 .
- the natural gas can be compressed to a pressure of typically 300 bar.
- step d) After the final cooling to T 1 by water cooling in step c), at least part of the gas is isenthalpically expanded in step d) to a pressure p expand of typically 150 bar. Due to the Joule-Thomson effect, the temperature of the gas is reduced to T 2 , typically to about 20°C.
- step e) the gas is further cooled to a temperature T 4 of about -75°C.
- Step f) is the return of the gas to the LNG tank, which typically includes further isenthalpic expansion and the separation of liquid and gaseous parts in the gas/liquid separator.
- the operating mode ii) as described above, in which the BOG is compressed to a pressure p low and expanded to p expand in the case of p low > Pexpand.
- This operating mode requires the middle and last compression stage to be set up to compress precompressed gas from a first pressure p 1 either to a pressure p high of, for example, 300 bar or to a pressure p low of, for example, 150 bar.
- the pressure can be regulated, for example, by a bypass with a controllable valve that is arranged in the last compression stage 103 . If the controllable valve can be regulated in such a way that each target pressure between p low and p high can be set, further pressures in the return line 8 are the figure 1 respectively in the diagram of figure 2 conceivable parallel below the dashed line c).
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- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
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Abstract
Die vorliegende Erfindung betrifft ein Verfahren zum Wiederverflüssigen und Rückführen von Abdampfgas (BOG) in einen Liquefied Natural Gas (LNG)-Tank, umfassend die Schritte: Verdichten eines aus dem Kopfraum eines LNG Tanks (3) entnommenen BOG auf einen Druck p<sub>high</sub>; Kühlen des verdichteten Gases auf eine Temperatur T<sub>1</sub>, bevorzugt durch Wasserkühlung (50); Ausdehnen von zumindest einem Teil des Gases aus Schritt c) auf einen Druck p<sub>expand</sub>; Kühlen des in Schritt d) ausgedehnten Gases, bevorzugt mittels eines Wärmetauschers (20) im Gegenstrom mit kühlendem BOG (F2) aus dem Kopfraum des LNG Tanks 3 auf eine Temperatur T<sub>4</sub>; Rückführen des Gases aus Schritt e) in den LNG Tank (3); wobei der Druck p<sub>high</sub> wenigstens 200 bar, bevorzugt wenigstens 250 bar, besonders bevorzugt wenigstens 300 bar beträgt, und wobei der Druck p<sub>expand</sub> 80 bis 180 bar, bevorzugt 120 bis 160 bar, besonders bevorzugt 150 bar beträgt.The present invention relates to a method for reliquefying and returning exhaust gas (BOG) to a liquefied natural gas (LNG) tank, comprising the steps of: compressing a BOG taken from the headspace of an LNG tank (3) to a pressure p<sub> high</sub>; cooling the compressed gas to a temperature T<sub>1</sub>, preferably by water cooling (50); expanding at least part of the gas from step c) to a pressure p<sub>expand</sub>; cooling the gas expanded in step d), preferably by means of a heat exchanger (20) in countercurrent with cooling BOG (F2) from the headspace of the LNG tank 3 to a temperature T<sub>4</sub>; returning the gas from step e) to the LNG tank (3); wherein the pressure p<sub>high</sub> is at least 200 bar, preferably at least 250 bar, particularly preferably at least 300 bar, and wherein the pressure p<sub>expand</sub> is 80 to 180 bar, preferably 120 to 160 bar, particularly preferably 150 bar.
Description
Die Erfindung betrifft das technische Gebiet der Wiederverflüssigung von Abdampfgas (BOG) aus einem Liquefied Natural Gas (LNG) Tank.The invention relates to the technical field of re-liquefaction of boil-off gas (BOG) from a liquefied natural gas (LNG) tank.
In letzter Zeit ist der Verbrauch von Flüssiggas wie z. B. verflüssigtem Erdgas (LNG) weltweit stark angestiegen. Flüssiggas, das durch Abkühlung von Erdgas auf eine extrem niedrige Temperatur gewonnen wird, hat ein kleines Volumen und damit gut geeignet für Lagerung und Transport. Darüber hinaus ist Flüssiggas wie LNG schadstoffarm und damit besser vereinbar mit Regulationen als beispielsweise Schweröl.Recently, the consumption of LPG such. B. liquefied natural gas (LNG) has risen sharply worldwide. LPG, obtained by cooling natural gas to an extremely low temperature, has a small volume, making it well suited for storage and transportation. In addition, liquid gas, like LNG, is low in pollutants and therefore more compatible with regulations than, for example, heavy oil.
LNG ist eine farblose und transparente Flüssigkeit, die durch Abkühlung von Erdgas, das hauptsächlich aus Methan besteht, auf etwa -163° C gewonnen wird. Da Erdgas jedoch bei einer extrem niedrigen Temperatur von -163° C. unter Normaldruck verflüssigt wird, kann LNG bei einem leichten Temperaturanstieg leicht verdampfen. In einem LNG-Lagertank wird daher kontinuierlich LNG auf natürliche Weise verdampft und dadurch boil off gas (BOG) erzeugt.LNG is a colorless and transparent liquid obtained by cooling natural gas, which consists mainly of methane, to around -163°C. However, since natural gas is liquefied at an extremely low temperature of -163°C under normal pressure, LNG can easily vaporize with a slight rise in temperature. In an LNG storage tank, LNG is therefore continuously vaporized naturally, thereby generating boil off gas (BOG).
Die Entstehung von BOG bedeutet einen Verlust an gespeichertem LNG und verringert also beispielsweise auf einem LNG-Tanker die Transporteffizienz. Wenn sich BOG in einem Lagertank ansammelt, besteht ausserdem die Gefahr, dass der Druck im Lagertank ansteigt und der Tank beschädigt wird.The formation of BOG means a loss of stored LNG and thus reduces transport efficiency on an LNG tanker, for example. In addition, if BOG accumulates in a storage tank, there is a risk that the pressure in the storage tank will rise and the tank will be damaged.
Zur Behebung des Problems wurde eine Methode vorgeschlagen, bei der BOG wieder verflüssigt wird, um es in einen LNG-Lagertank rückzuführen, eine Methode, bei der BOG als Energiequelle einem Verbrennungsmotor, wie z. B. einem Schiffsmotor, zugeführt wird, und Kombinationen davon. In der
Es ist daher die Aufgabe der vorliegenden Erfindung, ein Verfahren zur Teilrückverflüssigung von BOG respektive ein Teilrückverflüssigungssystem (PRS) bereitzustellen, bei dem BOG direkt als Kühlmittel verwendet wird und bei dem dennoch eine hohe Effizienz erreicht wird.It is therefore the object of the present invention to provide a method for the partial reliquefaction of BOG or a partial reliquefaction system (PRS) in which BOG is used directly as a coolant and in which high efficiency is nevertheless achieved.
Die Aufgabe wird durch ein Verfahren aufweisend die Merkmale von Anspruch 1, respektive eine Vorrichtung aufweisend die Merkmale von Anspruch 5, gelöst.The object is achieved by a method having the features of claim 1, or a device having the features of
Insbesondere wird die Aufgabe gelöst durch ein Verfahren zum Wiederverflüssigen und Rückführen von Abdampfgas (BOG) in einen Liquefied Natural Gas (LNG)-Tank, umfassend die Schritte:
- a) Entnehmen von BOG (F2) aus dem Kopfraum eines LNG Tanks;
- b) Verdichten des BOG auf einen Druck phigh;
- c) Kühlen des verdichteten Gases auf eine Temperatur T1, bevorzugt durch Wasserkühlung;
- d) Ausdehnen von zumindest einem Teil des Gases aus Schritt c) auf einen Druck pexpand;
- e) Kühlen des in Schritt d) ausgedehnten Gases, bevorzugt mittels eines Wärmetauschers im Gegenstrom mit kühlendem BOG (F2) aus dem Kopfraum des LNG Tanks auf eine Temperatur T4;
- f) Rückführen des Gases aus Schritt e) in den LNG Tank; wobei der Druck phigh wenigstens 200 bar, bevorzugt wenigstens 250 bar, besonders bevorzugt wenigstens 300 bar beträgt, und wobei der Druck pexpand 80 bis 180 bar, bevorzugt 120 bis 160 bar, besonders bevorzugt 150 bar beträgt.
- a) removing BOG (F2) from the headspace of an LNG tank;
- b) compression of the BOG to a pressure p high ;
- c) cooling the compressed gas to a temperature T 1 , preferably by water cooling;
- d) expanding at least part of the gas from step c) to a pressure p expand ;
- e) cooling the gas expanded in step d), preferably by means of a counter-current heat exchanger with cooling BOG (F2) from the headspace of the LNG tank to a temperature T 4 ;
- f) returning the gas from step e) to the LNG tank; where the pressure p high is at least 200 bar, preferably at least 250 bar, particularly preferably at least 300 bar, and where the pressure p expand is 80 to 180 bar, preferably 120 to 160 bar, particularly preferably 150 bar.
Dieses Verfahren beruht auf der Idee, dass die Kühlflüssigkeit, welche zur Rückverflüssigung des BOG in Schritt e) eingesetzt wird, nur beschränkt zur Verfügung steht und/oder sparsam eingesetzt werden soll. Im Falle von einem separaten Kühlkreislauf mit entsprechendem Kältemittel, typischerweise N2, kostet das Kühlen Energie. Wenn stattdessen BOG aus dem LNG-Tank als Kühlmittel verwendet wird, ist eine niedrige Fördermenge aus Sicht der Lagerungs-/Transporteffizient wünschenswert, insbesondere, wenn nicht gleichzeitig ein Motor mit dem Erdgas-Brennstoff betrieben werden muss oder wenn der Motor (zeitweise) einen nur geringen Brennstoffbedarf hat. Im Gegensatz dazu steht aber die Kühlflüssigkeit zum Kühlen des komprimierten Gases auf Umgebungstemperatur, insbesondere Wasser, praktisch unlimitiert zur Verfügung.This method is based on the idea that the coolant used to reliquefy the BOG in step e) is only available to a limited extent and/or should be used sparingly. In the case of a separate cooling circuit with a corresponding refrigerant, typically N 2 , cooling costs energy. If BOG from the LNG tank is used as the coolant instead, a low flow rate is desirable from a storage/transport efficiency perspective, particularly if an engine does not need to be run on the natural gas fuel at the same time, or if the engine (temporarily) only has one has low fuel requirements. In contrast to this, however, the cooling liquid for cooling the compressed gas to ambient temperature, in particular water, is available in practically unlimited quantities.
Die Erfinder haben erkannt, dass es daher sinnvoll sein kann, für den Kühlschritt e) ein Gas bereitzustellen, welches eine geringe Wärme aufweist. Dies kann erreicht werden, indem das Gas auf einen vergleichsweise hohen Druck phigh verdichtet wird und bei diesem hohen Druck durch Wasserkühlung gekühlt wird. Wenn daraufhin in Schritt d) das Gas zumindest teilweise isoenthalpisch entspannt wird, bevor es der Kühlung in Schritt e) zugeführt wird, kann mit der verfügbaren Kühlleistung ein höherer Anteil von Gas rückverflüssigt werden, als wenn ohne Schritt d) oder ausgehend von einem niedrigeren Druck (beispielsweise 150 bar) rückverflüssigt würde.The inventors have recognized that it can therefore be useful to provide a gas for the cooling step e) which has a low level of heat. This can be achieved by compressing the gas to a comparatively high pressure p high and cooling it by water cooling at this high pressure. If then in step d) the gas is at least partially expanded isoenthalpic before it is fed to the cooling in step e), a higher proportion of gas can be reliquefied with the available cooling capacity than if without step d) or starting from a lower pressure ( for example 150 bar) would be reliquefied.
Bevorzugt ist ein Verfahren zum Versorgen eines Hochdruck-Gaseinspritzmotors mit Gas, das in einem LNG-Tank teilweise als Abdampfgas (BOG, F2) gespeichert ist, und zum Wiederverflüssigen und Rückführen von BOG, umfassend die Schritte nach Anspruch 1, wobei in Schritt d) wenigstens ein erster Teil des Gases aus Schritt c) im Umfang des Brennstoffbedarfs eines Hochdruck-Gaseinspritzmotors über einen Auslass dem Hochdruck-Gaseinspritzmotor zugeführt wird und wenigstens ein zweiter Teil des Gases aus Schritt c) auf den Druck pexpand ausgedehnt wird.Preferred is a method for supplying a high-pressure gas-injected engine with gas stored in an LNG tank partially as boil-off gas (BOG, F2) and for reliquefying and recycling BOG, comprising the steps according to claim 1, wherein in step d) at least a first part of the gas from step c) to the extent of the fuel requirements of a high-pressure gas-injected engine is supplied via an outlet to the high-pressure gas-injected engine and at least a second part of the gas from step c) is expanded to the pressure p expand .
In dieser Ausführungsform kann das hochkomprimierte Gas bei Druck phigh entweder dazu verwendet werden, einen Hochdruck-Gaseinspritzmotor anzutreiben, oder rückverflüssigt werden. Insbesondere auf einem Flüssiggastanker ist Erdgas der Brennstoff der Wahl, um die Emission von Luftschadstoffen auf ein relativ geringes Mass zu beschränken. Die Einstellbarkeit der Menge, die an den Gaseinspritzmotor respektive in das PRS geleitet wird, erlaubt es, auf den klimatischen und meteorologischen Bedingung wie auch dem Brennstoffbedarf des Hochdruckgaseinspritzmotors flexibel Rechnung zu tragen.In this embodiment, the highly compressed gas at pressure p high can either be used to power a high pressure gas injected engine or reliquefied. Natural gas is the fuel of choice, particularly on an LNG tanker, in order to limit the emission of air pollutants to a relatively low level. The adjustability of the amount that is fed to the gas injection engine or into the PRS allows flexible consideration of the climatic and meteorological conditions as well as the fuel requirements of the high-pressure gas injection engine.
Weiter ist es bevorzugt, wenn im Verfahren wie vorstehend beschrieben dem Schritt b) ein Schritt 0) vorangeht und Schritt 0) das Auswählen ist zwischen
- einem Betriebsmodus i) Verdichten des BOG auf einen Druck phigh umfassend die Schritte b) bis d); und
- einem Betriebsmodus ii) Verdichten des BOG auf einen Druck plow, umfassend die Schritte
- b1) Verdichten des BOG auf einen Druck plow von 100 bis 199 bar, bevorzugt 140 bis 160 bar; und
- d1) Ausdehnen von zumindest einem Teil des Gases aus Schritt c) auf einen Druck pexpand, sofern plow > pex-pand;
- an operating mode i) compressing the BOG to a pressure p high comprising the steps b) to d); and
- a mode of operation ii) compressing the BOG to a pressure p low , comprising the steps of
- b1) compression of the BOG to a pressure p low of 100 to 199 bar, preferably 140 to 160 bar; and
- d1) expanding at least part of the gas from step c) to a pressure p expand , provided that p low > p ex-pand ;
In einem solchen Verfahren ist es möglich den Betriebsmodus anzupassen. Es hat sich herausgestellt, dass es bei tiefer Rückverflüssigungsrate effizient sein kann, lediglich auf einen tieferen Druck plow zu verdichten (Schritt b1), weil das BOG genügend Kühlkapazität liefert um den zu verflüssigenden Gasstrom auf ein ausreichend tiefes Temperaturniveau zu kühlen. Dagegen erweist sich das Verdichten auf eine hohen Druck bei hoher Verflüssigungsrate als effizienter, weil die zusätzliche Kühlung durch die Expansion des zu verflüssigenden Gases von phigh auf plow zu einer höheren Rückverflüssigungsrate und somit zu einem effizienteren Gesamtsystem beiträgt.In such a method, it is possible to adjust the operating mode. It has been found that at a low recondensation rate it can be efficient to simply compress to a lower pressure p low (step b1), because the BOG provides sufficient cooling capacity to cool the gas stream to be liquefied to a sufficiently low temperature level. On the other hand, compression to a high pressure at a high liquefaction rate proves to be more efficient because the additional cooling due to the expansion of the gas to be liquefied from p high to p low contributes to a higher re-liquefaction rate and thus to a more efficient overall system.
Besonders bevorzugt ist ein Verfahren, bei dem im Schritt 0) im Betriebsmodus i) ein Soll-Wert phigh im Bereich von 200 bis 300 bar ausgewählt wird und/oder im Betriebsmodus ii) ein Soll-Wert plow im Bereich von 100 bis 199 bar ausgewählt wird. Durch die so erhältliche, stufenlose Verstellbarkeit zwischen 100 und 300 bar ist es möglich, im Rückverflüssigungszyklus noch weitere Flexibilität zu gewinnen.A method is particularly preferred in which in step 0) in operating mode i) a target value p high in the range from 200 to 300 bar is selected and/or in operating mode ii) a target value p low in the range from 100 to 199 bar is selected. Thanks to the stepless adjustability between 100 and 300 bar that is available in this way, it is possible to gain even more flexibility in the recondensation cycle.
Ein Aspekt der Erfindung bezieht sich auf eine Vorrichtung zum Wiederverflüssigen und Rückführen von Abdampfgas (BOG) in einen Liquefied Natural Gas (LNG)-Tank umfassend
- einen Wärmetauscher, aufweisend eine Leitung zum Durchführen von Kühlfluid, bevorzugt von BOG aus einem LNG-Tank, und eine Leitung zum Durchführen von zu kühlendem komprimiertem Gas;
- eine mehrstufige Verdichteranordnung, die eingerichtet ist, BOG (F2) aus dem LNG-Tank auf einen Druck phigh zu verdichten;
- einen ersten Kühler;
- eine Rückführleitung; und
- eine erste Expansionseinheit, die eingerichtet ist, komprimiertes Gas von einem Druck phigh auf einen Druck pexpand auszudehnen;
- wobei die mehrstufige Verdichteranordnung stromaufwärts Fluid führend, optional über die Leitung des Wärmetauschers zum Durchführen von Kühlfluid, mit einer Entnahmeleitung mündend in den Kopfraum des LNG Tanks verbunden ist, und wobei die mehrstufige Verdichteranordnung stromabwärts Fluid führend mit dem ersten Kühler, weiter stromabwärts über die Rückführleitung mit der ersten Expansionseinheit und noch weiter stromabwärts mit der Leitung des Wärmetauschers zum Durchführen von zu kühlendem komprimiertem Gas verbunden ist, um das verdichtete und gekühlte Gas in den LNG Tank rückzuführen;
- wobei der Druck phigh wenigstens 200 bar, bevorzugt wenigstens 250 bar, besonders bevorzugt 300 bar beträgt; und wobei der Druck pexpand 80 bis 180 bar, bevorzugt 120 bis 160 bar, besonders bevorzugt 150 bar beträgt.
- a heat exchanger comprising a line for passing cooling fluid, preferably from BOG from an LNG tank, and a line for passing compressed gas to be cooled;
- a multi-stage compressor arrangement configured to compress BOG (F2) from the LNG tank to a pressure p high ;
- a first cooler;
- a return line; and
- a first expansion unit configured to expand compressed gas from a pressure p high to a pressure p expand ;
- wherein the multi-stage compressor assembly is upstream fluid-carrying, optionally via the line of the heat exchanger for passing cooling fluid therethrough, to a bleed line opening into the headspace of the LNG tank, and wherein the multi-stage compressor assembly is downstream fluid-carrying to the first cooler further downstream via the recycle line connected to the first expansion unit and further downstream to the line of the heat exchanger for passing compressed gas to be cooled, for returning the compressed and cooled gas to the LNG tank;
- wherein the pressure p high is at least 200 bar, preferably at least 250 bar, particularly preferably 300 bar; and wherein the pressure pexpand is 80 to 180 bar, preferably 120 to 160 bar, particularly preferably 150 bar.
Diese Vorrichtung löst die eingangs beschriene Aufgabe. Für den Kühlschritt im indirekten Wärmetauscher wird so ein Gas bereitgestellt, welches eine geringe Wärme aufweist. Dies wird erreicht, indem das Gas auf einen vergleichsweise hohen Druck phigh verdichtet wird und bei diesem hohen Druck durch Wasserkühlung gekühlt wird. Wenn daraufhin in Schritt d) das Gas zumindest teilweise isenthalpisch entspannt wird, bevor es der Kühlung im Wärmetauscher zugeführt wird, kann mit der verfügbaren Kühlleistung ein höherer Anteil von Gas rückverflüssigt werden, als wenn ohne dem Kühlschritt vorhergehende Ausdehnung, d.h. ausgehend von einem nur auf niedrigeren Druck (beispielsweise 150 bar) verdichteten Gas, gekühlt und rückverflüssigt würde.This device solves the task described above. In this way, a gas is provided for the cooling step in the indirect heat exchanger, which has a low level of heat. This is achieved by compressing the gas to a comparatively high pressure p high and cooling it with water at this high pressure. If then in step d) the gas at least is partially isenthalpic expanded before it is fed to the cooling in the heat exchanger, a higher proportion of gas can be reliquefied with the available cooling capacity than if without the cooling step preceding expansion, i.e. starting from a gas compressed only to a lower pressure (e.g. 150 bar). , cooled and reliquefied.
Ein mit der Vorrichtung verbundener Vorteil ist der Effizienzgewinn bei hoher Flussrate von BOG, wie vorstehend auf Verfahrensebene beschrieben. Ein weiterer konstruktiver Vorteil ist darin zu sehen, dass der Druck in der/den Zwischenstufe/n vor der letzten Kompressionsstufe nicht kontrolliert werden muss. Wenn beispielsweise durch eine Abzweigleitung im Anschluss an eine Zwischenstufe (beispielsweise bei plow) ein Teil des Gases entnommen und dem PRS zugeführt werden würde, müsste der Druck nach dieser Zwischenstufe typischerweise mit einem Druckkontrollventil (Pressure Control Valve, PCV) reguliert werden. Wenn dagegen die gesamte geförderte BOG-Menge einheitlich auf den Druck phigh verdichtet wird, reicht ein einziger PCV aus, was die Kosten der Vorrichtung senkt. Schliesslich reicht dank der verbesserten Effizienz der Vorrichtung ein kleineres PRS, und dank dem geringeren Gasfluss auch eine kleinere mehrstufige Verdichteranordnung aus. Dies gilt überraschenderweise sogar trotz des Umstands, dass alle Kompressionsstufen dafür ausgerichtet sein müssen, den gesamt BOG Fluss zu bearbeiten. Kleinere Vorrichtungen sparen wertvollen Platz, insbesondere wenn die Vorrichtung auf einem Schiff, e.g. einem Tanker, eingesetzt werden soll. Auch wird für die effiziente Rückverflüssigung weniger Energie benötigt.An advantage associated with the device is the efficiency gain at high flow rate of BOG, as described above at the process level. Another constructive advantage can be seen in the fact that the pressure in the intermediate stage(s) does not have to be checked before the last compression stage. For example, if some of the gas were to be withdrawn and fed to the PRS through a branch line following an intermediate stage (e.g., at p low ), the pressure after that intermediate stage would typically need to be regulated with a pressure control valve (PCV). On the other hand, if the entire conveyed BOG amount is uniformly compressed to the pressure p high , a single PCV suffices, which reduces the cost of the device. Finally, thanks to the improved efficiency of the device, a smaller PRS is sufficient, and thanks to the lower gas flow, a smaller multi-stage compressor arrangement is also sufficient. This is surprisingly true even despite the fact that all stages of compression must be geared towards handling the overall BOG flow. Smaller devices save valuable space, especially if the device is to be used on a ship, eg a tanker. Less energy is also required for efficient reliquefaction.
In einer bevorzugten Ausführungsform ist die Vorrichtung Teil eines Brenngasversorgungssystems zum Versorgen eines Hochdruck-Gaseinspritzmotors mit in einem LNG-Tank gespeichertem Gas, zusätzlich umfassend
- einen Auslass, der Fluid leitend stromabwärts der mehrstufigen Verdichteranordnung angeordnet ist und weiter stromabwärts in eine Versorgungsleitung für einen Hochdruck-Gaseinspritzmotor mündet,
- an outlet fluidly disposed downstream of the multi-stage compressor assembly and further downstream opening into a supply line for a high-pressure gas-injected engine,
Es ist der Vorteil einer solchen Vorrichtung als Teil eines Brenngasversorgungssystems, dass das hochkomprimierte Gas bei Druck phigh wahlweise rückverflüssigt werden kann oder dazu verwendet werden kann, einen Hochdruck-Gaseinspritzmotor anzutreiben. Die Einstellbarkeit der Menge, die an den Gaseinspritzmotor respektive in das PRS geleitet wird, erlaubt es, den klimatischen und meteorologischen Bedingung wie auch dem Brennstoffbedarf des Hochdruckgaseinspritzmotors (z.B. Fahrgeschwindigkeit) flexibel Rechnung zu tragen.It is the advantage of such a device as part of a fuel gas supply system that the highly compressed gas at pressure p high can be optionally reliquefied or used to drive a high pressure gas injection engine. The adjustability of the quantity fed to the gas-injection engine or into the PRS allows the climatic and meteorological conditions as well as the fuel requirements of the high-pressure gas-injection engine (e.g. driving speed) to be flexibly taken into account.
In einer Ausführungsform umfasst die Vorrichtung weiter
- eine zweite Expansionseinheit, die eingerichtet ist, komprimiertes Gas von einem Druck pexpand auf einen Druck pknock-out-drum (typischerweise 1-3 bar über dem Tankdruck) auszudehnen,
- einen Gas-Flüssigkeits-Abscheider, der Fluid führend stromabwärts an die zweite Expansionseinheit anschliesst und eingerichtet ist, bei einem Druck pknock-out-drum einen verflüssigten Gasanteil in den LNG-Tank zurück zu speisen und einen gasförmigen Anteil in die Entnahmeleitung zu führen;
- a second expansion unit that is set up to expand compressed gas from a pressure p expand to a pressure p knock-out-drum (typically 1-3 bar above the tank pressure),
- a gas-liquid separator, which connects fluid-carrying downstream to the second expansion unit and is set up, at a pressure p knock-out-drum, to feed a liquefied gas portion back into the LNG tank and to lead a gaseous portion into the extraction line;
Durch die erneute Ausdehnung in der zweiten Expansionseinheit (z.B. Expansionsventil, Expander) erfährt das Gas nochmals eine Kühlung durch Joule-Thomsen Entspannung. Anschliessend kann die durch den Gas-Flüssigkeitsabscheider abgetrennte gasförmige Komponente mit dem aus dem Lagertank entnommene BOG kombiniert und dem Wärmetauscher als Kühlmittel zugeführt werden. Die flüssige Komponente wird in den Lagertank geleitet. Dank der beschriebenen Anordnung kann vorzugsweise bei gleicher Menge von zur Verfügung stehendem Kühlmittel ein höher relativer Anteil des BOG rückverflüssigt werden.Due to the renewed expansion in the second expansion unit (e.g. expansion valve, expander), the gas is cooled again by Joule-Thomsen expansion. The gaseous component separated by the gas-liquid separator can then be combined with the BOG taken from the storage tank and fed to the heat exchanger as coolant. The liquid component is fed into the storage tank. Thanks to the arrangement described, a higher relative proportion of the BOG can preferably be reliquefied with the same amount of coolant available.
Es ist bevorzugt, dass der erste Kühler ein Wasserkühler ist, bevorzugt wird Wasser aus dem Kühlwassersystem des Schiffes als Kühlmittel verwendet, sodass das komprimierte Gas auf eine Temperatur von 35 bis 45°C kühlbar ist. Wasser ist reichlich vorhanden, zumal wenn die Vorrichtung auf einem Schiff verwendet wird. Durch die Kühlung auf die dadurch erreichbare Temperatur von 35 bis 45°C ausgehend von Gas aufweisend einen besonders hohen Druck, ergibt sich gegenüber Prozessen ausgehend von tieferen Drucken eine niedrigere Enthalpie bereits nach dem ersten Kühlungsschritt.It is preferred that the first cooler is a water cooler, preferably water from the ship's cooling water system is used as coolant, so that the compressed gas can be cooled to a temperature of 35 to 45°C. Water is plentiful, especially when the device is used on a ship. Due to the cooling to the achievable temperature of 35 to 45° C. based on gas having a particularly high pressure, a lower enthalpy results already after the first cooling step compared to processes based on lower pressures.
In einer bevorzugten Ausführungsform weist die mehrstufige Verdichteranordnung eine erste Kompressionsstufe auf, wobei die erste Kompressionsstufe eingerichtet ist, BOG (F2) aus dem LNG-Tank auf einen ersten Druck p1 zwischen 6 und 18 bar zu verdichten, und wobei die erste Kompressionsstufe wenigstens einen Labyrinth gedichteten Kolbenkompressoren aufweist.In a preferred embodiment, the multi-stage compressor arrangement has a first compression stage, the first compression stage being set up to compress BOG (F2) from the LNG tank to a first pressure p1 between 6 and 18 bar, and the first compression stage having at least one labyrinth has sealed piston compressors.
Wenn die erste Kompressionsstufe wenigstens einen Labyrinth gedichteten Kolbenkompressoren aufweist, bevorzugt ausschliesslich Labyrinth gedichtete Kolbenkompressoren umfasst, kann die erste Kompressionsstufe schmiermittelarm respektive schmiermittelfrei betrieben werden. Dies hat einerseits den Vorteil, dass die Qualität des verdichteten Gases nicht durch Verunreinigungen mit Schmiermittel beeinträchtigt wird. Andererseits kann die Gefahr vermieden werden, dass bei den tiefen Temperaturen des BOG in niedrigen Kompressionsstufen das Schmiermittel (typischerweise Öl) sich verfestigt und den Verschleiss der Maschinenteile fördert.If the first compression stage has at least one labyrinth-sealed piston compressor, preferably comprises exclusively labyrinth-sealed piston compressors, the first compression stage can have little or no lubricant operate. On the one hand, this has the advantage that the quality of the compressed gas is not impaired by contamination with lubricant. On the other hand, the danger that at the low temperatures of the BOG in low compression stages the lubricant (typically oil) solidifies and promotes wear of the machine parts can be avoided.
In einer bevorzugten Ausführungsform weist die mehrstufige Verdichteranordnung der Vorrichtung eine mittlere und eine letzte Kompressionsstufe auf, die eingerichtet sind, vorverdichtetes Gas von einem ersten Druck p1 auf den Druck phigh, bevorzugt wahlweise auf den Druck phigh oder den Druck plow zu verdichten, wobei die letzte Kompressionsstufe einen Bypass mit ansteuerbarem Ventil aufweist, um den Rückfluss und damit den Förderdruck nach der letzten Kompressionsstufe anzusteuern, wobei Gas derart über den Bypass rückspeisbar ist, dass das Gas am Auslass den vorgegebenen Solldruckwert phigh, bevorzugt den vorgegebenen Solldruckwert Druck phigh oder plow, aufweist.In a preferred embodiment, the multi-stage compressor arrangement of the device has a middle and a last compression stage, which are set up to compress pre-compressed gas from a first pressure p1 to pressure p high , preferably optionally to pressure p high or pressure p low , wherein the last compression stage has a bypass with a controllable valve in order to control the return flow and thus the delivery pressure after the last compression stage, wherein gas can be fed back via the bypass in such a way that the gas at the outlet has the specified target pressure value p high , preferably the specified target pressure value pressure p high or p low .
Eine solche Vorrichtung hat die bereits zuvor genannten Vorteile, dass die Effizienz der Rückverflüssigung für hohe Gasförderraten verbessert und die Grösse der Vorrichtungselemente reduziert werden kann. Wenn nun die mehrstufige Verdichteranordnung dank des Bypass mit ansteuerbarem Ventil variabel betrieben werden kann, bzw. dadurch am Auslass Gas aufweisend einen variablen Druck zwischen plow und phigh bereitgestellt werden kann, ergeben sich weitere Vorteile. Die mehrstufige Verdichteranordnung kann so eingerichtet sein, dass der Seitenstrom zur Rückverflüssigung bei tiefen Rückverflüssigungsraten lediglich auf plow verdichtet wird, was für kleine Rückverflüssigungsraten effizienter ist. Zudem kann die Lebenserwartung der Geräte verbessert werden, wenn sie während eines beträchtlichen Teils der Betriebszeit mit nur 50 % des Nominaldrucks betrieben werden.Such a device has the advantages already mentioned above that the efficiency of the reliquefaction can be improved for high gas conveying rates and the size of the device elements can be reduced. If the multi-stage compressor arrangement can now be operated variably thanks to the bypass with a controllable valve, or as a result a variable pressure between p low and p high can be provided at the gas outlet, further advantages result. The multi-stage compressor arrangement can be set up such that the side stream for recondensation at low recondensation rates is compressed only to p low , which is more efficient for small recondensation rates. In addition, the life expectancy of the devices can be improved when they are operated at only 50% of the nominal pressure for a significant part of the operating time.
Es ist besonders bevorzugt, wenn der Bypass mit ansteuerbarem Ventil derart regulierbar ist, dass jeder Soll-Druck zwischen 100 und 300 bar einstellbar ist. Dies erlaubt dem Benutzer zusätzliche Flexibilität, um den klimatischen und meteorologischen Bedingungen sowie dem Brennstoffbedarf des Motors / der Motoren Rechnung zu tragen.It is particularly preferred if the bypass can be regulated with a controllable valve in such a way that any desired pressure can be set between 100 and 300 bar. This allows the user additional flexibility to accommodate climatic and meteorological conditions as well as fuel requirements of the engine(s).
In einer Ausführungsform umfasst die letzte Kompressionsstufe wenigstens einen mit Kolbenring gedichteten Kolbenkompressor, bevorzugt zwei mit Kolbenring gedichtete Kolbenkompressoren. Mit Kolbenring gedichtete, vorzugsweise geschmierte, Kolbenkompressoren ermöglichen das Verdichten des Gases auf Druck im Bereich von phigh.In one embodiment, the final compression stage comprises at least one piston ring sealed reciprocating compressor, preferably two piston ring sealed reciprocating compressors. Piston compressors sealed with piston rings, preferably lubricated, enable the gas to be compressed to a pressure in the range of p high .
Die Vorrichtung wie vorstehend beschrieben kann weiter umfassen eine Abzweigleitung, welche Fluid leitend stromabwärts von der ersten Kompressionsstufe angeordnet ist und die weiter stromabwärts in eine Versorgungsleitung für einen Niederdruck-Gaseinspritzmotor und/oder einer Gasverbrennungseinheit mündet.The device as described above may further comprise a branch line which is fluid-conducting downstream of the first compression stage and which further downstream opens into a supply line for a low-pressure gas-injected engine and/or a gas combustion unit.
Damit kann der ein Motor, der bei niedrigem Druck (p1) betrieben wird, wie z.B. ein X-DF-Motor, mit Brennstoff versorgt werden, der nach der ersten Kompressionsstufe entnommen wird. In dieser Ausführungsform ist es besonders günstig, wenn die erste Kompressionsstufe schmiermittelarm oder schmiermittellos abgedichtet ist, weil so ein Brennstoff von hoher Qualität an den Niederdruck Gaseinspritzmotor und/oder die Gasverbrennungseinheit geleitet werden kann.Thus, an engine operating at low pressure (p 1 ), such as an X-DF engine, can be supplied with fuel that is extracted after the first stage of compression. In this embodiment it is particularly advantageous if the first compression stage is sealed with little or no lubricant, because high quality fuel can then be supplied to the low-pressure gas-injected engine and/or the gas-combustion unit.
Die Erfindung bezieht sich auf die Verwendung der Vorrichtung wie vorstehend beschrieben auf einem Schiff, beispielsweise einem Erdgastanker, insbesondere einem Schiff, das mittels eines Hochdruck-Gaseinspritzmotors angetrieben wird. Bei der Verwendung auf einem Schiff kommen aufgrund der knappen Platzverhältnisse die vorstehend genannten Vorteile, insbesondere die reduzierte Grösse der Vorrichtung, besonders deutlich zum Tragen.The invention relates to the use of the device as described above on a ship, for example a natural gas tanker, in particular a ship which is propelled by means of a high-pressure gas-injection engine. When used on a ship, the advantages mentioned above, in particular the reduced size of the device, come into play particularly clearly due to the limited space available.
Die Erfindung wir anhand von Figuren weiter verständlich gemacht. Die Figuren dienen der Illustration und sind nicht einschränkend zu verstehen.The invention is further explained with reference to figures. The figures are for illustration and are not meant to be limiting.
Es zeigen:
- Figur 1
- Schematische Darstellung einer Vorrichtung gemäss der vorliegenden Erfindung;
Figur 2- Schematisches Mollier-Diagramm zur Verdeutlichung eines Verfahrens gemäss der vorliegenden Erfindung.
- figure 1
- Schematic representation of a device according to the present invention;
- figure 2
- Schematic Mollier diagram to illustrate a method according to the present invention.
In der gezeigten Ausführungsform umfasst die mehrstufige Verdichteranordnung 10 eine erste Kompressionsstufe mit Kolbenkompressoren 71 und 72 und zugehörigen Kühlern, eine mittlere Kompressionsstufe mit Kolbenkompressor 73 und zugehörigem Kühler, sowie eine letzte Kompressionsstufe mit Kolbenkompressoren 74 und 75 und zugehörigen Kühlern. Die erste Kompressionsstufe 71,72 ist eingerichtet, das BOG auf einen Druck p1 von typischerweise 7 bar zu verdichten. Ein Teil des so verdichteten, bevorzugt schmiermittelfrei verdichteten BOG kann bei Bedarf über Abzweigleitung 6 dem Niederdruck-Gaseinspritzmotor 4 zugeführt werden. Die erste Kompressionsstufe kann mittels Bypass aufweisend ein Druckkontrollventil druckkontrolliert sein (nicht gezeigt).In the embodiment shown, the
Die mehrstufige Verdichteranordnung 10 ist stromabwärts Fluid führend mit einem ersten Wasserkühler 50 verbunden, wodurch das komprimierte Gas auf typischerweise 40°C gekühlt wird. Der Auslassdruck der höchsten Kompressionsstufe, hier bestehend aus Kolbenkompressoren 75 und 74 und zugehörigen Wasserkühlern, ist über einen Bypass 19 mit Druckkontrollventil 9 reguliert. Nach Austritt aus dem ersten Wasserkühler 50 kann das komprimierte BOG wahlweise über den Auslass 7 einem Hochdruck-Gaseinspritzmotor 2 als Kraftstoff zugeführt oder über die Rückführleitung 8 einer ersten Expansionseinheit 60, beispielsweise einem Expansionsventil oder einem Expander, zugeleitet werden. Typischerweise wird überschüssiges BOG, das den Brennstoffbedarf des Motors 2 übersteigt, der Rückführleitung 8 zugeführt. Das Gas wird in der ersten Expansionseinheit 60 auf einen Druck pex-pand von ca. 150 bar entspannt. Durch die isenthalpe Druckminderung erfährt das komprimierte Erdgas eine neuerliche Kühlung und kann also ausgehend von ca. 20°C im indirekten Wärmeaustausch mit dem BOG (F2) aus dem LNG Tank 3 im Wärmetauscher 20 weiter gekühlt zu werden.The
Das durch die Verdichteranordnung komprimierte und durch Wasserkühlung 50, Expansion 60 und Wärmetausch 20 gekühlte BOG wird in einer zweiten Expansionseinheit 30 erneut entspannt, nunmehr auf einen Druck pknock-out-drum von typischerweise 1 bar, und schliesslich durch einen Gas-/Flüssigkeitsabscheider 40 in eine flüssige Komponente und eine gasförmige Komponente getrennt. Die durch den Gas-/Flüssigkeitsabscheider 40 abgetrennte flüssige Komponente wird in den LNG-Tank rückgespeist und die durch den Gas-/Flüssigkeits-abscheider abgetrennte gasförmige Komponente wird in der Entnahmeleitung 5 mit dem aus dem LNG-Tank austretenden BOG kombiniert und dann dem Wärmetauscher 20 zugeführt, um als Kühlfluid verwendet zu werden.The compressed by the compressor arrangement and cooled by water cooling 50,
Im BOG-Rückverflüssigungssystem wie in
In Schritt b) folgt das Verdichten auf phigh, beispielsweise entsprechend der in
Aus der
Claims (14)
wobei in Schritt d) wenigstens ein erster Teil des Gases aus Schritt c) im Umfang des Brennstoffbedarfs eines Hochdruck-Gaseinspritzmotors (2) über einen Auslass (7) dem Hochdruck-Gaseinspritzmotor (2) zugeführt wird und wenigstens ein zweiter Teil des Gases aus Schritt c) auf den Druck pexpand ausgedehnt wird.Method for supplying a high-pressure gas-injection engine (2) with gas stored in an LNG tank (3) partly as flash-off gas (BOG, F2) and for reliquefying and recycling BOG, comprising the steps according to claim 1,
wherein in step d) at least a first portion of the gas from step c) to the extent of the fuel requirement of a high-pressure gas-injected engine (2) via an outlet (7). High-pressure gas injection engine (2) is supplied and at least a second part of the gas from step c) is expanded to the pressure p expand .
Priority Applications (2)
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EP22156041.0A EP4227620A1 (en) | 2022-02-10 | 2022-02-10 | Method and device for reliquifying and returning vapour gas to an lng tank |
PCT/EP2023/053266 WO2023152267A1 (en) | 2022-02-10 | 2023-02-10 | Method and apparatus for reliquefaction and recycling of boil-off gas into an lng tank |
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EP22156041.0A EP4227620A1 (en) | 2022-02-10 | 2022-02-10 | Method and device for reliquifying and returning vapour gas to an lng tank |
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Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2629035A1 (en) * | 2010-10-13 | 2013-08-21 | Mitsubishi Heavy Industries, Ltd. | Liquefaction method, liquefaction device, and floating liquefied gas production equipment comprising same |
KR20140075581A (en) * | 2012-12-11 | 2014-06-19 | 대우조선해양 주식회사 | BOG Multi-Step Reliquefaction System And Method For Boiled Off Gas |
KR20160103324A (en) * | 2015-02-24 | 2016-09-01 | 대우조선해양 주식회사 | BOG Re-liquefaction Apparatus and Method for Vessel |
US20190351988A1 (en) | 2017-01-25 | 2019-11-21 | Daewoo Shipbuilding & Marine Engineering Co., Ltd. | Boil-off gas re-liquefying method for lng ship |
US20200208780A1 (en) * | 2017-07-31 | 2020-07-02 | Daewoo Shipbuilding & Marine Engineering Co., Ltd. | Boil-off gas reliquefaction system |
-
2022
- 2022-02-10 EP EP22156041.0A patent/EP4227620A1/en active Pending
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2023
- 2023-02-10 WO PCT/EP2023/053266 patent/WO2023152267A1/en unknown
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2629035A1 (en) * | 2010-10-13 | 2013-08-21 | Mitsubishi Heavy Industries, Ltd. | Liquefaction method, liquefaction device, and floating liquefied gas production equipment comprising same |
KR20140075581A (en) * | 2012-12-11 | 2014-06-19 | 대우조선해양 주식회사 | BOG Multi-Step Reliquefaction System And Method For Boiled Off Gas |
KR20160103324A (en) * | 2015-02-24 | 2016-09-01 | 대우조선해양 주식회사 | BOG Re-liquefaction Apparatus and Method for Vessel |
US20190351988A1 (en) | 2017-01-25 | 2019-11-21 | Daewoo Shipbuilding & Marine Engineering Co., Ltd. | Boil-off gas re-liquefying method for lng ship |
US20200208780A1 (en) * | 2017-07-31 | 2020-07-02 | Daewoo Shipbuilding & Marine Engineering Co., Ltd. | Boil-off gas reliquefaction system |
Non-Patent Citations (1)
Title |
---|
MAN DIESEL & TURBO: "ME-GI Dual Fuel MAN B&W Engines", 1 April 2012 (2012-04-01), XP055505574, Retrieved from the Internet <URL:https://www.corporate.man.eu/man/media/content_medien/doc/global_corporate_website_1/verantwortung_1/megatrends_2/klimawandel/me_gi_dual_fuel_en_01.pdf> [retrieved on 20180907] * |
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