WO2016059996A1 - Bog compression equipment and reciprocating compressor control method - Google Patents

Bog compression equipment and reciprocating compressor control method Download PDF

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Publication number
WO2016059996A1
WO2016059996A1 PCT/JP2015/078199 JP2015078199W WO2016059996A1 WO 2016059996 A1 WO2016059996 A1 WO 2016059996A1 JP 2015078199 W JP2015078199 W JP 2015078199W WO 2016059996 A1 WO2016059996 A1 WO 2016059996A1
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Prior art keywords
capacity
flow rate
operating
gas flow
reciprocating
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PCT/JP2015/078199
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French (fr)
Japanese (ja)
Inventor
正悟 長根
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株式会社Ihi
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Priority to JP2016554043A priority Critical patent/JP6256815B2/en
Publication of WO2016059996A1 publication Critical patent/WO2016059996A1/en

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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/06Control using electricity
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17CVESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C13/00Details of vessels or of the filling or discharging of vessels

Definitions

  • the present disclosure relates to a BOG compression facility for compressing boil-off gas (BOG) generated in a storage tank for low-temperature liquefied gas, and a control method for a reciprocating compressor.
  • BOG boil-off gas
  • Boil Off Gas In storage tanks for low-temperature liquefied gases such as LNG, LEG, and LPG, a large amount of boil-off gas (Boil Off Gas, hereinafter referred to as “BOG”) is generated during storage due to external heat input. Therefore, in order to prevent the pressure in the storage tank from rising, a BOG compression facility for compressing BOG has been proposed and used (for example, Patent Documents 1 to 3).
  • Patent Document 1 discloses a high-pressure compressor having a suction valve with an unloader and a counterbalanced reciprocating compressor.
  • Patent Document 2 discloses a BOG high-pressure compressor and a reliquefaction device.
  • Patent Document 3 discloses a BOG multistage positive displacement compressor.
  • the counterbalanced reciprocating compressor, the BOG high-pressure compressor, and the BOG multistage positive displacement compressor disclosed in Patent Documents 1 to 3 are hereinafter referred to as “two-stage reciprocating compressors”.
  • the reciprocating compressor is characterized by a large compression ratio and high operating efficiency compared to a turbo compressor.
  • the two-stage reciprocating compressor can drive the low-pressure piston and the high-pressure piston with a single drive source (for example, a motor) to compress the BOG generated in the storage tank to a high pressure (for example, 4 to 6 MPa).
  • BOG compressed with a two-stage reciprocating compressor is processed by sending it to a customer (for example, a power plant).
  • the BOG may be compressed to a high pressure (eg, 4 to 6 MPa) depending on the application of the BOG at the customer (eg, gas turbine fuel).
  • the two-stage reciprocating compressor has a problem that the load fluctuation is large because the load is greatly different between the low pressure compression and the high pressure compression.
  • the single-stage reciprocating compressor has only a low-pressure piston or a high-pressure piston, and therefore has a feature of low load fluctuation and high operating efficiency.
  • the BOG generated in the storage tank is compressed to a high pressure (for example, 4 to 6 MPa) using a reciprocating compressor (for example, a single-stage reciprocating compressor) having a large compression ratio, small load fluctuation, and high operating efficiency. Can be considered.
  • a reciprocating compressor for example, a single-stage reciprocating compressor
  • the pressure of BOG generated in the storage tank is very low (for example, normal pressure to 0.02 MPa). Therefore, in order to compress to a high pressure (for example, 4 to 6 MPa), it is conceivable to arrange low-pressure and high-pressure reciprocating compressors in series and provide an intermediate pipe therebetween. In addition, it can also compress to a high pressure by single stage compression using the reciprocating compressor for high pressures.
  • the volume of the intermediate pipe is small (for example, about 1 to 5% of the space volume above the storage tank), and the reciprocating compressor is activated and stopped for a long time (for example, 30 to 60). Seconds). For this reason, if an imbalance occurs in the gas flow rates of the low-pressure and high-pressure reciprocating compressors, the pressure in the intermediate pipe between them suddenly rises or falls, and the control of the number of operating high-pressure reciprocating compressors follows the pressure fluctuation. There was a possibility that it could not be done.
  • An object of the present disclosure is to provide a control method for a BOG compression facility and a reciprocating compressor that can suppress an imbalance in gas flow rate and prevent a sudden change in pressure in a pipe.
  • a plurality of first reciprocating compressors that compress BOG generated in a storage tank to a first pressure
  • a plurality of second reciprocating compressors that compress the first pressure BOG to a second pressure
  • An intermediate pipe communicating the discharge side of the first reciprocating compressor and the suction side of the second reciprocating compressor
  • a rated maximum flow rate detector that detects the rated maximum flow rate of the BOG that can flow into the intermediate pipe from a plurality of locations
  • a BOG compression facility is provided that includes a number control device that controls the number of operating second reciprocating compressors based on the rated maximum flow rate from the plurality of locations.
  • the BOG compression facility described above is prepared,
  • the rated maximum flow rate detector detects the rated maximum flow rate of BOG that can flow into the intermediate pipe from the plurality of locations,
  • a control method for a reciprocating compressor is provided, wherein the number control device controls the number of operating second reciprocating compressors based on the rated maximum flow rate from the plurality of locations.
  • the number of operating units of the plurality of second reciprocating compressors is controlled by the number control device based on the rated maximum flow rates of the BOGs from a plurality of locations that can flow into the intermediate pipe.
  • the second reciprocating compressor can be started or stopped before the pressure fluctuation occurs. Therefore, the followability of the control of the number of operating units of the second reciprocating compressor is enhanced, so that an imbalance in the gas flow rate can be suppressed and a sudden change in the pipe pressure can be prevented.
  • 1 is an overall system diagram of a BOG compression facility according to an embodiment of the present disclosure. It is a schematic diagram which shows the specific example of a single stage type reciprocating compressor. It is a schematic diagram which shows another specific example of a single stage type reciprocating compressor. It is explanatory drawing of the capacity
  • capacitance adjustment apparatus. 1 is an overall flow diagram of a capacity adjustment method for a reciprocating compressor according to an embodiment of the present disclosure. It is explanatory drawing which shows the relationship between the total gas flow volume G and the operating capacity W.
  • flow rate means “weight flow rate” unless otherwise specified.
  • the “rated maximum flow rate” means a “maximum flow rate” (that is, a maximum weight flow rate) preset for each device.
  • Numberer control means control for changing the number of operating units. The number of operating units is an integer having a minimum value of 1 during operation.
  • Capacity adjustment means control for changing the operating capacity of an operating reciprocating compressor. The “operating capacity” is the weight flow rate of gas that can be compressed by the reciprocating compressor in operation. Therefore, the “maximum operating capacity” of the reciprocating compressor means “rated maximum flow rate”.
  • FIG. 1 is an overall system diagram of a BOG compression facility according to an embodiment of the present disclosure.
  • 1 is a low-temperature liquefied gas such as LNG, LEG, LPG, 2 is a storage tank, 3 is a supply line for low-temperature liquefied gas 1, 4 is a pump, 5 is an evaporator, 6 is a gas transfer line, and 7 is a merge Tube 8 is a customer.
  • 1 is a low-temperature liquefied gas such as LNG, LEG, LPG
  • 2 is a storage tank
  • 3 is a supply line for low-temperature liquefied gas 1
  • 4 is a pump
  • 5 is an evaporator
  • 6 is a gas transfer line
  • 7 is a merge Tube 8 is a customer.
  • the low-temperature liquefied gas 1 stored in the storage tank 2 is supplied to the pump 4 by the supply line 3, the low-temperature liquefied gas 1 is pressurized by the pump 4, and the low-temperature liquefied gas 1 is evaporated by the evaporator 5.
  • the evaporated gas (for example, natural gas) can be supplied to the customer 8.
  • the customer 8 is, for example, a power plant, and low temperature liquefied gas 1 having a pressure of 4 to 6 MPa (hereinafter referred to as “high pressure”) is supplied to the customer 8 as fuel for a boiler or a gas turbine.
  • high pressure low temperature liquefied gas 1 having a pressure of 4 to 6 MPa
  • the BOG compression facility of the present embodiment includes a first control device 10, a first pressure detector 11, a plurality of first reciprocating compressors 12, a plurality of second reciprocating compressors 14, an intermediate pipe 16, and a rated maximum flow rate detector 18. And a second control device 20.
  • the pressure of BOG generated in the storage tank 2 is low (for example, normal pressure to 0.02 MPa).
  • the pressure of BOG generated in the storage tank 2 is referred to as “the 0th pressure P0”.
  • the upper part of the storage tank 2 and the suction side of the first reciprocating compressor 12 are connected by a BOG discharge line 15.
  • the plurality of first reciprocating compressors 12 are arranged in parallel and each sucks BOG generated in the storage tank 2 through the BOG discharge line 15 and compresses it to the first pressure P1.
  • the first pressure P1 is an intermediate pressure (for example, 1 to 3 MPa).
  • the number of first reciprocating compressors 12 is five in this figure, but may be two to four or six or more.
  • the first pressure detector 11 is provided in the upper part of the storage tank 2 or in the BOG discharge line 15 and detects the pressure of the BOG (the 0th pressure P0) generated in the storage tank 2.
  • the first control device 10 is, for example, a computer (PC), and receives BOG pressure data detected by the first pressure detector 11. Based on the received pressure data, the first controller 10 controls the plurality of first reciprocating compressors 12 so that the zeroth pressure P0 falls within a preset pressure range (for example, normal pressure to 0.02 MPa). To do.
  • a preset pressure range for example, normal pressure to 0.02 MPa
  • the time taken to start and stop the first reciprocating compressor 12 is, for example, 30 to 60 seconds.
  • the space volume in the upper part of the storage tank 2 is very large compared to the volume of the intermediate pipe 16 (for example, 20 to 100 times the volume of the intermediate pipe 16)
  • the pressure is detected by the first pressure detector 11.
  • the upper pressure of the storage tank 2 can be maintained within a preset pressure range by the first control device 10 and the first pressure detector 11.
  • the plurality of second reciprocating compressors 14 are arranged in parallel and each compresses the BOG of the first pressure P1 compressed by the first reciprocating compressor 12 to the second pressure P2.
  • the second pressure P2 is preferably a high pressure (eg, 4 to 6 MPa) that matches the customer 8 (eg, a power plant).
  • the number of second reciprocating compressors 14 is set so that the entire amount of BOG supplied from the intermediate pipe 16 can be compressed.
  • the number of second reciprocating compressors 14 is three in this figure, but may be two or four or more.
  • the intermediate pipe 16 is a gas pipe that communicates the discharge side of the plurality of first reciprocating compressors 12 and the suction side of the plurality of second reciprocating compressors 14.
  • the volume of the intermediate pipe 16 is very small as compared with the space volume above the storage tank 2, for example, about 1 to 5% of the space volume of the storage tank 2.
  • the present embodiment is not limited to this volume, and for example, a gas reservoir may be provided in the intermediate pipe 16.
  • off-gas flows into the intermediate pipe 16 from processes 9 other than the first reciprocating compressor 12.
  • the off gas should have substantially the same composition as BOG.
  • the process 9 means a process or equipment for generating off-gas by the storage system for the low-temperature liquefied gas 1.
  • the process 9 is not limited to the process in the BOG compression equipment of this embodiment, Other processes and equipment may be sufficient as long as off-gas (for example, BOG) generate
  • the discharge sides of the plurality of second reciprocating compressors 14 are connected to the junction pipe 7 described above via high-pressure gas lines 17.
  • the plurality of first reciprocating compressors 12 compress the BOG generated in the storage tank 2 to the first intermediate pressure P1
  • the plurality of second reciprocating compressors 14 compress the BOG having the first pressure P1.
  • the BOG compressed to the second pressure P ⁇ b> 2 merges with the gas from the evaporator 5 in the merge pipe 7 and is supplied to the customer 8.
  • the rated maximum flow rate detector 18 detects the rated maximum flow rate of the BOG that can flow into the intermediate pipe 16 from a plurality of locations.
  • the plurality of locations are the first reciprocating compressor 12 in operation.
  • the number of first reciprocating compressors 12 in operation is the number based on the control signal of the number of operating units by the second control device 20.
  • the above-mentioned plurality of locations may further include the process 9.
  • the rated maximum flow rate of BOG that can flow into the intermediate pipe 16 from the process 9 is known in advance, and the storage device (not shown) of the first control device 10, the second control device 20, or the rated maximum flow rate detector 18. ) Is stored.
  • “can flow in” means that it is not necessary to actually flow in, and it is sufficient that it can flow in.
  • the rated maximum flow rate of the first reciprocating compressor 12 is the maximum operating capacity when the operating capacity W is adjustable.
  • the rated maximum flow rate of the process 9 is the maximum value when the inflow amount from the process 9 varies.
  • the intermediate pipe 16 is provided with a total gas flow rate detector 13 and a second pressure detector 19.
  • the total gas flow rate detector 13 detects the total gas flow rate G flowing into the intermediate pipe 16 (that is, the weight flow rate actually flowing in), and outputs it to the second control device 20.
  • the second pressure detector 19 detects the pressure of the BOG in the intermediate pipe 16 and outputs it to the second control device 20.
  • the second control device 20 includes a number control device 20a and a capacity adjustment device 20b.
  • the number control device 20a is based on the rated maximum flow rate from the plurality of locations (the first reciprocating compressor 12 being operated, or the first reciprocating compressor 12 being operated and the process 9), as described above. Control the number of operating units. The number of operating units is set so that the entire amount of BOG supplied from the intermediate pipe 16 can be compressed.
  • the capacity adjusting device 20b adjusts the operating capacity W of each second reciprocating compressor 14 during operation based on the total gas flow rate G flowing into the intermediate pipe 16.
  • the operating capacity W of the second reciprocating compressor 14 when the operating capacity W of the second reciprocating compressor 14 can be adjusted, the operating capacity W of the second reciprocating compressor 14 in operation is adjusted, and the sum is obtained from the total gas flow rate G flowing into the intermediate pipe 16. Is also controlled to be larger.
  • the BOG compression facility of this embodiment further includes a recycle line 21 and a return gas flow rate control valve 22.
  • the recycle line 21 is a piping line that bypasses the second reciprocating compressor 14 and communicates the discharge side with the intermediate piping 16.
  • the recycle line 21 directly communicates the high-pressure gas line 17 and the intermediate pipe 16 described above, but the discharge side and the suction side of the second reciprocating compressor 14 may be directly communicated.
  • the recycling line 21 is not limited to one, and may be two or more.
  • the return gas flow rate control valve 22 is provided in the recycle line 21 and controls the gas flow rate returning from the discharge side of the second reciprocating compressor 14 to the intermediate pipe 16. This control is preferably set so that the pressure of the intermediate pipe 16 detected by the second pressure detector 19 falls within a preset pressure range (for example, the first pressure P1 ⁇ ⁇ and ⁇ are arbitrary pressures).
  • the second pressure detector 19 is omitted, a pilot control valve is used as the return gas flow rate control valve 22, and the return gas flow rate control valve is set at the pressure of the intermediate pipe 16 (pilot pressure) without going through the second control device 20. 22 may be directly controlled.
  • FIGS. 2A and 2B are schematic views showing a specific example of a single-stage reciprocating compressor.
  • the single-stage reciprocating compressor of FIG. 2A In the single-stage reciprocating compressor of FIG. 2A, two cylinders C are opposed to each other, and two pistons D are driven by a single drive source M (for example, a motor), and each piston D is reciprocated. Thus, gas is compressed at a total of four locations. Each cylinder C is provided with an unload valve V that returns compressed gas to the suction side, and one or both of compressions by reciprocation of each cylinder C can be unloaded (no load). Yes. Therefore, the single-stage reciprocating compressor of FIG. 2A can change the operating capacity W to five stages by the combination of on / off of the four unload valves V (only a part is shown). Hereinafter, these five stages of operation capacity W are referred to as 0, first capacity W1, second capacity W2, third capacity W3, and fourth capacity W4 from the smallest. The fourth capacity W4 is the maximum operating capacity.
  • the single-stage reciprocating compressor of FIG. 2B In the single-stage reciprocating compressor of FIG. 2B, four cylinders C are arranged radially, and four pistons D are driven by a single driving source M (for example, a motor). The gas is compressed at a total of 4 points. Each cylinder C is provided with an unload valve V for returning the compressed gas to the suction side so that each cylinder C can be unloaded (no load). Therefore, the single stage reciprocating compressor of FIG. 2B also changes the operating capacity W to five stages by the combination of on / off of the four unload valves V (only a part is shown) as in FIG. 2A. Can do.
  • a single driving source M for example, a motor
  • the gas is compressed at a total of 4 points.
  • Each cylinder C is provided with an unload valve V for returning the compressed gas to the suction side so that each cylinder C can be unloaded (no load). Therefore, the single stage reciprocating compressor of FIG. 2B also changes the operating capacity W to five stages
  • variable capacity steps of the single-stage reciprocating compressor is not limited to the above-described five stages, and may be two stages (that is, only on / off), three, four stages, or six stages or more.
  • the first reciprocating compressor 12 is not limited to the single-stage reciprocating compressor described above, and may be a multi-stage reciprocating compressor.
  • the maximum operating capacities of the plurality of first reciprocating compressors 12 may be the same or different.
  • the second reciprocating compressor 14 is preferably the above-described single-stage reciprocating compressor.
  • the maximum operating capacities of the plurality of second reciprocating compressors 14 may be the same or different.
  • FIG. 3 is an explanatory diagram of capacity adjustment by one single-stage reciprocating compressor. This figure is a diagram showing the relationship between the load factor 0, A1, A2, A3, 100%, the operating capacity W, and the processing flow rate when the capacity can be changed in five stages.
  • the processing flow rate means a gas flow rate processed by one single-stage reciprocating compressor.
  • the symbol g indicates the maximum flow rate (hereinafter referred to as the processable flow rate g) that can be processed by the single-stage reciprocating compressor having the corresponding operating capacity W (that is, the load factor). This processable flow rate g is equal to the corresponding operating capacity W.
  • the combination of on / off of the above-described four unload valves V corresponds to each stage of load factor 0, A1, A2, A3, 100%.
  • the operating capacity W can be adjusted in five stages of 0, W1, W2, W3, and W4 (in this example, the capacity difference between any adjacent steps is W1).
  • the load factors 0, A1, A2, A3, and 100% are, for example, 0, 25, 50, 75, and 100% of the maximum operating capacity.
  • FIG. 4 is a configuration diagram of the number control device 20a.
  • the number control device 20 a is, for example, a computer (PC), and includes a storage device 23, a calculation device 24, and an output device 25.
  • the storage device 23 is a memory such as a RAM, a ROM, or a hard disk.
  • the arithmetic device 24 is a CPU, for example.
  • the output device 25 is, for example, an output terminal or an output relay.
  • the control method for the reciprocating compressor according to the present embodiment is executed by the second control device 20.
  • This control method performs unit control and capacity adjustment described below.
  • the capacity adjustment may not be performed, and in this case, the capacity adjustment device 20b may be omitted.
  • the number control device 20a that is, the arithmetic device 24 includes a maximum total gas flow rate prediction unit 24a, a command number calculation unit 24b, and a command output unit 24c.
  • FIG. 5 is an overall flowchart of the method for controlling the number of reciprocating compressors according to this embodiment.
  • the method of the present embodiment includes steps (steps) S1 to S8.
  • step S1 the above-described BOG compression facility is prepared.
  • step S2 the rated maximum flow rate detector 18 detects the rated maximum flow rate of BOG that can flow into the intermediate pipe 16 from a plurality of locations.
  • step S3 the maximum total gas flow rate prediction unit 24a predicts the maximum total gas flow rate Gmax based on the rated maximum flow rates from the plurality of locations described above.
  • the plurality of locations described above include the first reciprocating compressor 12 in operation.
  • the 1st reciprocating compressor 12 which is not drive
  • the plurality of locations described above further include the process 9, in step S3, based on each rated maximum flow rate detected in step S2 and the rated maximum flow rate of the process 9 stored in the storage device described above, The maximum total gas flow rate prediction unit 24a predicts the maximum total gas flow rate Gmax.
  • the rated maximum flow rates (that is, the maximum operating capacity) are G1, G2, and G3, and the rated maximum flow rate of the process 9 is G9.
  • the rated maximum flow rate means the fourth capacity W4.
  • the operating capacity W of the first reciprocating compressor 12 during operation may be any of 0, W1, W2, W3, and W4.
  • the function “ROUNDUP” means rounding up to an integer.
  • the command number calculation unit 24b gives priority.
  • the second reciprocating compressor 14 may be selected in descending order. At this time, the sum of the rated maximum flow rates of the selected second reciprocating compressor 14 is set to exceed the above-described maximum total gas flow rate Gmax.
  • the priority should be based on operating efficiency, maintainability, lifespan, and the like.
  • the total of the maximum rated flow rates of the N second reciprocating compressors 14 Exceeds the above-mentioned maximum total gas flow rate Gmax. Accordingly, the entire amount of BOG supplied from the intermediate pipe 16 can be compressed by the N second reciprocating compressors 14.
  • the command output unit 24c compares the current operating number N2 of the operating second reciprocating compressor 14 with the calculated commanded number N, and the operating operating number N2 is calculated. Is commanded to increase or decrease the operating number N2 (or so that the operating number N2 approaches the designated number N).
  • step S5 when the command number N exceeds the operating number N2 (YES) in step S5, the command output unit 24c outputs a command to increase the number of operating units N2 in step S6. Due to this increase command, the number N2 of the second reciprocating compressors 14 is changed to N2 + 1. After outputting the additional command, the process returns to step S3.
  • step S7 the command output unit 24c outputs a reduction command for reducing the operating number N2 in step S8 when the number of units less than the current operating number N2 exceeds the command number N (YES).
  • the command output unit 24c outputs a reduction command for reducing the operating number N2 in step S8 when the number of units less than the current operating number N2 exceeds the command number N (YES).
  • the operating number N2 in operation can be made to coincide with the commanded number N calculated.
  • the total of the maximum rated flow rates of the N second reciprocating compressors 14 is the maximum total gas described above.
  • Exceeding the flow rate Gmax the entire amount of BOG supplied from the intermediate pipe 16 can be compressed.
  • the capacity adjusting device 20b has one or both of the following (1) and (2). I do. (1) The current operation of each second reciprocating compressor 14 in which the total gas flow rate G to the plurality of second reciprocating compressors 14 in operation (that is, the total gas flow rate G flowing through the intermediate pipe 16) is in operation. When the total sum Ws of the capacities (that is, the processable flow rate g) is exceeded, at least one of the operating capacities of the plurality of second reciprocating compressors 14 being operated is switched to the maximum operating capacity side.
  • the total gas flow rate G is smaller than the total current operating capacity Ws of each second reciprocating compressor 14 in operation, and a value obtained by subtracting the total gas flow rate G from the total Ws (Ws ⁇ G ) Is larger than the switchable amount of the operation capacity of the second reciprocating compressor 14 (that is, the operation capacity is switched in steps of one stage as shown in FIG. 3), each second reciprocal compression during operation
  • the operating capacity of the plurality of second reciprocating compressors 14 in operation is switched to the minimum operating capacity side while maintaining the operating capacity of the machine 14 at a value greater than zero.
  • the capacity adjusting device 20b is configured such that the total operation capacity (processable flow rate g) of FIG. 3 in each second reciprocating compressor 14 in operation is the total gas to the plurality of second reciprocating compressors 14 in operation. Set to exceed flow rate G.
  • the capacity adjustment by the capacity adjustment device 20b is performed on some or all of the plurality of second reciprocating compressors 14 that are operating by the number control performed by the number control device 20a described above. .
  • FIG. 6 is a configuration diagram of the capacity adjustment device 20b.
  • the capacity adjustment device 20b is, for example, a computer (PC), and includes a storage device 33, a calculation device 34, and an output device 35.
  • the storage device 33 is a memory such as a RAM, a ROM, or a hard disk.
  • the computing device 34 is a CPU, for example.
  • the output device 35 is, for example, an output terminal or an output relay.
  • the capacity adjustment device 20b that is, the calculation device 34 includes a first capacity adjustment unit 34a and a second capacity adjustment unit 34b.
  • FIG. 7 is an overall flowchart of the capacity adjustment method for the reciprocating compressor according to the present embodiment.
  • the method of the present embodiment includes steps (steps) S11 to S18.
  • step S11 the above-described BOG compression facility is prepared.
  • step S ⁇ b> 12 the total gas flow rate detector 13 detects the total gas flow rate G actually flowing into the intermediate pipe 16.
  • Steps S13 to S18 show the capacity adjustment method of the reciprocating compressor according to this embodiment. Hereinafter, this capacity adjustment will be described.
  • the capacity adjusting device 20b has an operating capacity W (that is, a processable flow rate g) as shown in FIG.
  • the operating capacity W is set so as to exceed the gas flow rate G.
  • the total operating flow W of the second reciprocating compressor 14 in operation is the total gas flow rate G actually flowing into the intermediate pipe 16.
  • the operating capacity W of each second reciprocating compressor 14 during operation is set so as to exceed. For example, when two or more units are operating and there is no priority, the operation capacity W (processable flow rate) shared by each second reciprocating compressor 14 with respect to the total gas flow rate G actually flowing into the intermediate pipe 16. g) is set as appropriate, and is set so that the sum of the N operating capacities W (see FIG. 3) exceeds the total gas flow rate G.
  • the capacity adjusting device 20b has each second reciprocating device 14 in operation so as to satisfy all the following conditions.
  • the operating capacity W of the compressor 14 is adjusted.
  • (B) The load factor of the second reciprocating compressor 14 is higher in descending order of priority. That is, priorities are set in advance for the plurality of second reciprocating compressors 14 in operation, and the second reciprocating compressor 14 having a higher priority has a higher operating capacity (load factor).
  • the operating capacity (load factor) of all the second reciprocating compressors 14 in operation is greater than zero. The priority should be based on operating efficiency, maintainability, life, etc.
  • FIG. 8 is an explanatory diagram showing the relationship between the total gas flow rate G and the operating capacity W.
  • the left side shows the total gas flow rate G flowing into the intermediate pipe 16
  • the right side shows the operating capacity W of the three second reciprocating compressors 14 in operation.
  • the first priority K from the top is No. 1
  • the second is No. 2
  • the third is No. 3.
  • the hatched portion on the right side indicates the actual gas flow rate
  • the blank portion indicates the unloaded portion of the operating capacity W.
  • the first operating capacity W from the top is W4, the second is W3, the third is W1, satisfies the relationship of W4 + W3 + W1> G, and satisfies the condition (A). Further, W4>W3> W1, and the condition (B) is satisfied. Further, W4, W3, W1 ⁇ W1, and the condition (C) is satisfied.
  • the total operating capacity W of the second reciprocating compressor 14 in operation is The total gas flow rate G actually flowing into the intermediate pipe 16 is set to be exceeded.
  • step S14 the first capacity adjustment unit 34a calculates the sum ⁇ WA of the operating capacities W from the priority order 1 to (K ⁇ 1) with respect to the priority order K.
  • ⁇ WA means the sum of the operating capacities W of the second reciprocating compressor 14 having a higher priority than the priority K being calculated. For example, in FIG. 8, the first unit has the highest priority, and there is no higher priority, so the first ⁇ WA is zero. Further, since the second one from the top has the second highest priority and one higher priority, ⁇ WA is the first operating capacity W4.
  • the first capacity adjustment unit 34a calculates the sum ⁇ WB of the minimum capacities (the above-described first capacities W1) from (K + 1) to N with respect to the priority order K.
  • the minimum capacity is an adjustable minimum capacity greater than zero.
  • ⁇ WB is calculated on the assumption that all the second reciprocating compressors 14 having a lower priority than the second reciprocating compressor 14 being calculated have the minimum capacity. This assumption is for ensuring the operating capacity W of the second reciprocating compressor 14 during operation to be equal to or greater than the minimum capacity.
  • the first unit has the highest priority, and there are two units with lower priority, so the first ⁇ WB is 2W1.
  • the second one from the top has the second priority, and there is one lower priority, so the second ⁇ WB is W1.
  • the first capacity adjustment unit 34a adjusts the operating capacity W with respect to the priority order K based on the remaining capacity obtained by subtracting ⁇ WA and ⁇ WB from the total gas flow rate G.
  • the first capacity adjusting unit 34a sets the operating capacity of the second reciprocating compressor 14 to the maximum operating capacity. You can do it.
  • the first capacity adjusting unit 34a determines the operating capacity of the second reciprocating compressor 14 from the remaining capacity.
  • the operating capacity may be set large and closest to the remaining capacity. For example, in FIG.
  • the operating capacity W of the second reciprocating compressor 14 having a higher priority and the minimum capacity of the second reciprocating compressor 14 having a lower priority being secured are being calculated.
  • the operating capacity W of the second reciprocating compressor 14 can be set to the maximum.
  • the operating capacity W of the second reciprocating compressor 14 is set as follows by the second capacity adjusting unit 34b when the priority order K is N (NO in step S13).
  • step S17 the second capacity adjusting unit 34b calculates the sum ⁇ WC of the operating capacities W from the first to the (N ⁇ 1) th for the priority N.
  • ⁇ WC means the sum of the operating capacities W of all the second reciprocating compressors 14 having a higher priority than the N-th second reciprocating compressor 14. For example, in FIG. 8, the one on the top of the third has the third priority, and there is no lower priority, so ⁇ WC is W4 + W3.
  • the BOG generated in the storage tank 2 is compressed to the first pressure P1 by the plurality of first reciprocating compressors 12, and the first reciprocating compressor 14 is used to compress the first BOG.
  • the BOG at the pressure P1 can be compressed to the second pressure P2. Therefore, the BOG generated in the storage tank 2 can be compressed to a high pressure (for example, 4 to 6 MPa) using a reciprocating compressor.
  • the number of operating units of the plurality of second reciprocating compressors 14 is controlled by the number control device 20a based on the rated maximum flow rate of BOG from a plurality of places that can flow into the intermediate pipe 16, the pressure fluctuations in the intermediate pipe 16 Before this occurs, the second reciprocating compressor 14 can be started or stopped early. Accordingly, the followability of the control of the number of operating units of the second reciprocating compressor 14 is enhanced, so that an imbalance in the gas flow rate can be suppressed and a sudden change in the pressure in the pipe can be prevented.
  • each second reciprocating compressor 14 in operation is adjusted by the capacity adjustment device 20b based on the total gas flow rate G actually flowing into the intermediate pipe 16 from a plurality of locations.
  • the operating capacity W can be adjusted early before the pressure fluctuation occurs. Accordingly, the followability of the capacity adjustment of each second reciprocating compressor 14 is enhanced, so that an imbalance in the gas flow rate can be suppressed and a sudden change in the pipe internal pressure can be prevented.
  • the BOG compression facility according to the above-described embodiment may be described as in the following supplementary notes 1 to 8.
  • BOG compression equipment A plurality of first reciprocating compressors that compress BOG generated in the storage tank to a first pressure; A plurality of second reciprocating compressors that compress the first pressure BOG to a second pressure; An intermediate pipe communicating the discharge side of the first reciprocating compressor and the suction side of the second reciprocating compressor; A rated maximum flow rate detector that detects the rated maximum flow rate of the BOG that can flow into the intermediate pipe from a plurality of locations; A number control device for controlling the number of operating second reciprocating compressors based on the maximum rated flow rate from the plurality of locations.
  • the number control device is: A maximum total gas flow prediction unit for predicting a maximum total gas flow from each of the rated maximum flows; A command number calculator for calculating a command number of the second reciprocating compressor based on the maximum total gas flow rate; A command output unit that compares the current operating number of the second reciprocating compressor with the commanded number and commands an increase or decrease in the operating number so that the current operating number matches the commanded number; .
  • the command number calculation unit calculates the command number from the maximum total gas flow rate and the rated maximum flow rate of each of the second reciprocating compressors, The command output unit outputs a command to increase the number of operating units when the commanded number exceeds the current operating number, and reduces the number of operating units when the number less than the current operating number exceeds the commanded number Output reduction command.
  • the BOG compression facility described above includes a recycle line that bypasses the second reciprocating compressor and communicates the discharge side with the intermediate pipe.
  • a return gas flow rate control valve that is provided in the recycle line and controls a gas flow rate that returns from the discharge side of the second reciprocating compressor to the intermediate pipe.
  • the operating capacity of each of the second reciprocating compressors can be adjusted stepwise to two or more different operating capacities, A total gas flow detector for detecting the total gas flow actually flowing into the intermediate pipe from the plurality of locations; A capacity adjusting device that adjusts the operating capacity of each of the second reciprocating compressors that are operating under the control of the number of operating units based on the total gas flow rate.
  • the capacity adjusting device is (1) At least one of the plurality of second reciprocating compressors in operation when the total gas flow rate flowing through the intermediate pipe exceeds the total operating capacity of the second reciprocating compressors in operation. Or (2) the total gas flow rate G is smaller than the total operating capacity Ws of the second reciprocating compressors in operation, and the total Ws When the value (Ws ⁇ G) obtained by subtracting the total gas flow rate G is larger than the switchable amount of the operation capacity of the second reciprocating compressor, the operation capacity of each of the second reciprocating compressors in operation is less than zero. While maintaining the large value, the operating capacity of at least one of the plurality of second reciprocating compressors in operation is switched to the minimum operating capacity side.
  • Appendix 7 In Appendix 5, when there are two or more second reciprocating compressors in operation and priority is set for each of the plurality of second reciprocating compressors in operation, (A) The total operating capacity of the second reciprocating compressor in operation exceeds the total gas flow rate flowing into the intermediate pipe, (B) the second reciprocating compressor having a higher priority has a higher operating capacity, and (C) The operating capacity of all the second reciprocating compressors in operation is greater than zero.
  • the capacity adjusting device adjusts an operating capacity of each of the second reciprocating compressors.
  • the capacity adjusting device has N second reciprocating compressors in operation (N ⁇ 2), and each of the plurality of second reciprocating compressors in operation is assigned a priority. If In order of priority, the operating capacity from the first to the Kth (1 ⁇ K ⁇ N ⁇ 1) is the sum of the operating capacity from the total gas flow to the first to the (K ⁇ 1) th.
  • a first capacity adjustment unit that adjusts based on the remaining capacity obtained by subtracting the sum of the minimum capacity greater than zero from the (K + 1) th to the Nth
  • a second capacity adjustment unit that adjusts the N-th priority operation capacity to a value larger than the remaining capacity obtained by subtracting the sum of the operation capacity from the first to the (N ⁇ 1) th unit from the total gas flow rate.
  • the total gas flow rate detector detects the total gas flow rate actually flowing into the intermediate pipe from the plurality of locations,
  • the plurality of second reciprocating compressors compress the first pressure BOG to a second pressure,
  • the operating capacity of each of the second reciprocating compressors that are operating under the control of the number of operating units is adjusted in two or more steps by a capacity adjusting device based on the total gas flow rate.

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Abstract

BOG compression equipment is provided with multiple first reciprocating compressors (12), multiple second reciprocating compressors (14), an intermediate pipe (16), a rated maximum flow detector (18), and a unit number-controlling unit (20a). Respective rated maximum BOG flows that can flow into the intermediate pipe (16) from multiple sites are detected by the rated maximum flow detector (18). On the basis of the rated maximum flows from the multiple sites, the unit number-controlling unit (20a) controls the number of second reciprocating compressors (14) to be operated.

Description

BOG圧縮設備とレシプロ圧縮機の制御方法BOG compression equipment and reciprocating compressor control method
 本開示は、低温液化ガスの貯蔵タンク内で発生するボイルオフガス(BOG)を圧縮するBOG圧縮設備と、レシプロ圧縮機の制御方法に関する。 The present disclosure relates to a BOG compression facility for compressing boil-off gas (BOG) generated in a storage tank for low-temperature liquefied gas, and a control method for a reciprocating compressor.
 LNG、LEG、LPGなど低温液化ガスの貯蔵タンクでは、貯蔵中に外部からの入熱によりボイルオフガス(Boil Off Gas、以下「BOG」という)が大量に発生する。
 そのため、貯蔵タンク内の圧力が上昇するのを防止するために、BOGを圧縮するBOG圧縮設備が提案され使用されている(例えば、特許文献1~3)。
In storage tanks for low-temperature liquefied gases such as LNG, LEG, and LPG, a large amount of boil-off gas (Boil Off Gas, hereinafter referred to as “BOG”) is generated during storage due to external heat input.
Therefore, in order to prevent the pressure in the storage tank from rising, a BOG compression facility for compressing BOG has been proposed and used (for example, Patent Documents 1 to 3).
 特許文献1は、アンローダ付き吸入弁を有する高圧圧縮機と、対向釣合い形往復圧縮機を開示している。
 特許文献2は、BOG高圧圧縮機と再液化装置を開示している。
 特許文献3は、BOG多段容積型圧縮機を開示している。
Patent Document 1 discloses a high-pressure compressor having a suction valve with an unloader and a counterbalanced reciprocating compressor.
Patent Document 2 discloses a BOG high-pressure compressor and a reliquefaction device.
Patent Document 3 discloses a BOG multistage positive displacement compressor.
特開2002-115663号公報JP 2002-115663 A 特開2008-286211号公報JP 2008-286211 A 特開2012-122352号公報JP 2012-122352 A
 特許文献1~3に開示されている対向釣合い形往復圧縮機、BOG高圧圧縮機、及びBOG多段容積型圧縮機を、以下、「2段式レシプロ圧縮機」と呼ぶ。
 レシプロ圧縮機は、ターボ圧縮機と比較して圧縮比が大きく、運転効率が高い特徴がある。
 また2段式レシプロ圧縮機は、単一の駆動源(例えばモータ)で低圧ピストンと高圧ピストンを駆動し、貯蔵タンクで発生するBOGを高圧(例えば4~6MPa)まで圧縮することができる。
The counterbalanced reciprocating compressor, the BOG high-pressure compressor, and the BOG multistage positive displacement compressor disclosed in Patent Documents 1 to 3 are hereinafter referred to as “two-stage reciprocating compressors”.
The reciprocating compressor is characterized by a large compression ratio and high operating efficiency compared to a turbo compressor.
The two-stage reciprocating compressor can drive the low-pressure piston and the high-pressure piston with a single drive source (for example, a motor) to compress the BOG generated in the storage tank to a high pressure (for example, 4 to 6 MPa).
 2段式レシプロ圧縮機で圧縮したBOGは、需要先(例えば発電所)に送ることで処理される。需要先でのBOGの用途(例えばガスタービンの燃料)により、BOGを高圧(例えば4~6MPa)に圧縮する場合がある。 BOG compressed with a two-stage reciprocating compressor is processed by sending it to a customer (for example, a power plant). The BOG may be compressed to a high pressure (eg, 4 to 6 MPa) depending on the application of the BOG at the customer (eg, gas turbine fuel).
 しかし、2段式レシプロ圧縮機は、低圧圧縮時と高圧圧縮時とで負荷が大きく相違するため、負荷変動が大きい問題点がある。 However, the two-stage reciprocating compressor has a problem that the load fluctuation is large because the load is greatly different between the low pressure compression and the high pressure compression.
 一方、単段式レシプロ圧縮機は、低圧ピストン又は高圧ピストンのみを有するため、負荷変動が小さく運転効率が高い特徴がある。 On the other hand, the single-stage reciprocating compressor has only a low-pressure piston or a high-pressure piston, and therefore has a feature of low load fluctuation and high operating efficiency.
 そこで、圧縮比が大きく、負荷変動が小さく、運転効率が高いレシプロ圧縮機(例えば単段式レシプロ圧縮機)を用いて、貯蔵タンクで発生するBOGを高圧(例えば4~6MPa)まで圧縮することが考えられる。 Therefore, the BOG generated in the storage tank is compressed to a high pressure (for example, 4 to 6 MPa) using a reciprocating compressor (for example, a single-stage reciprocating compressor) having a large compression ratio, small load fluctuation, and high operating efficiency. Can be considered.
 しかし貯蔵タンクで発生するBOGの圧力は非常に低い(例えば、常圧~0.02MPa)。そのため、高圧(例えば4~6MPa)まで圧縮するには、低圧用と高圧用のレシプロ圧縮機を直列に配置し、その間に中間配管を設けることが考えられる。
 なお、高圧用のレシプロ圧縮機を用いて、単段圧縮で高圧まで圧縮することもできる。
However, the pressure of BOG generated in the storage tank is very low (for example, normal pressure to 0.02 MPa). Therefore, in order to compress to a high pressure (for example, 4 to 6 MPa), it is conceivable to arrange low-pressure and high-pressure reciprocating compressors in series and provide an intermediate pipe therebetween.
In addition, it can also compress to a high pressure by single stage compression using the reciprocating compressor for high pressures.
 また、貯蔵タンクで発生するBOGのガス流量は貯蔵タンクの使用状況や季節(気温の変化など)による変動が大きい。そのため、低圧用と高圧用にそれぞれ複数台のレシプロ圧縮機を設置し、状況に応じてレシプロ圧縮機の運転台数を制御することが考えられる。 In addition, the flow rate of BOG generated in the storage tank varies greatly depending on the storage tank usage and the season (change in temperature, etc.). Therefore, it is conceivable to install a plurality of reciprocating compressors for low pressure and high pressure, respectively, and control the number of operating reciprocating compressors according to the situation.
 しかし、貯蔵タンク上部の空間容積と比較すると、中間配管の容積は小さく(例えば貯蔵タンク上部の空間容積の1~5%程度)、かつレシプロ圧縮機は起動と停止に長時間(例えば30~60秒)かかる。そのため、低圧用と高圧用のレシプロ圧縮機のガス流量にアンバランスが生じると、その間の中間配管内の圧力が急上昇又は急低下し、高圧用のレシプロ圧縮機の運転台数制御が圧力変動に追従できない可能性があった。 However, compared with the space volume above the storage tank, the volume of the intermediate pipe is small (for example, about 1 to 5% of the space volume above the storage tank), and the reciprocating compressor is activated and stopped for a long time (for example, 30 to 60). Seconds). For this reason, if an imbalance occurs in the gas flow rates of the low-pressure and high-pressure reciprocating compressors, the pressure in the intermediate pipe between them suddenly rises or falls, and the control of the number of operating high-pressure reciprocating compressors follows the pressure fluctuation. There was a possibility that it could not be done.
 本開示の目的は、ガス流量のアンバランスを抑制し、配管内圧力の急変を防止することができるBOG圧縮設備とレシプロ圧縮機の制御方法を提供することにある。 An object of the present disclosure is to provide a control method for a BOG compression facility and a reciprocating compressor that can suppress an imbalance in gas flow rate and prevent a sudden change in pressure in a pipe.
 本開示の1つの観点によれば、貯蔵タンクで発生するBOGを第1圧まで圧縮する複数の第1レシプロ圧縮機と、
 前記第1圧のBOGを第2圧まで圧縮する複数の第2レシプロ圧縮機と、
 前記第1レシプロ圧縮機の吐出側と前記第2レシプロ圧縮機の吸入側とを連通する中間配管と、
 複数箇所から前記中間配管に流入し得るBOGの定格最大流量をそれぞれ検出する定格最大流量検出器と、
 前記複数箇所からの前記定格最大流量に基づき、前記第2レシプロ圧縮機の運転台数を制御する台数制御装置と、を備えるBOG圧縮設備が提供される。
According to one aspect of the present disclosure, a plurality of first reciprocating compressors that compress BOG generated in a storage tank to a first pressure;
A plurality of second reciprocating compressors that compress the first pressure BOG to a second pressure;
An intermediate pipe communicating the discharge side of the first reciprocating compressor and the suction side of the second reciprocating compressor;
A rated maximum flow rate detector that detects the rated maximum flow rate of the BOG that can flow into the intermediate pipe from a plurality of locations;
A BOG compression facility is provided that includes a number control device that controls the number of operating second reciprocating compressors based on the rated maximum flow rate from the plurality of locations.
 また本開示の他の観点によれば、上述したBOG圧縮設備を準備し、
 前記定格最大流量検出器により、前記複数箇所から前記中間配管に流入し得るBOGの定格最大流量をそれぞれ検出し、
 前記台数制御装置により、前記複数箇所からの前記定格最大流量に基づき、前記第2レシプロ圧縮機の運転台数を制御する、レシプロ圧縮機の制御方法が提供される。
According to another aspect of the present disclosure, the BOG compression facility described above is prepared,
The rated maximum flow rate detector detects the rated maximum flow rate of BOG that can flow into the intermediate pipe from the plurality of locations,
A control method for a reciprocating compressor is provided, wherein the number control device controls the number of operating second reciprocating compressors based on the rated maximum flow rate from the plurality of locations.
 上記本開示によれば、中間配管に流入し得る複数箇所からのBOGのそれぞれの定格最大流量に基づき、台数制御装置により、複数の第2レシプロ圧縮機の運転台数を制御するので、中間配管内に圧力変動が生じる前に第2レシプロ圧縮機の起動又は停止ができる。
 従って、第2レシプロ圧縮機の運転台数制御の追従性が高まるので、ガス流量のアンバランスを抑制し、配管内圧力の急変を防止することができる。
According to the present disclosure, the number of operating units of the plurality of second reciprocating compressors is controlled by the number control device based on the rated maximum flow rates of the BOGs from a plurality of locations that can flow into the intermediate pipe. The second reciprocating compressor can be started or stopped before the pressure fluctuation occurs.
Therefore, the followability of the control of the number of operating units of the second reciprocating compressor is enhanced, so that an imbalance in the gas flow rate can be suppressed and a sudden change in the pipe pressure can be prevented.
本開示の実施形態によるBOG圧縮設備の全体系統図である。1 is an overall system diagram of a BOG compression facility according to an embodiment of the present disclosure. 単段式レシプロ圧縮機の具体例を示す模式図である。It is a schematic diagram which shows the specific example of a single stage type reciprocating compressor. 単段式レシプロ圧縮機の別の具体例を示す模式図である。It is a schematic diagram which shows another specific example of a single stage type reciprocating compressor. 単段式レシプロ圧縮機による容量調整の説明図である。It is explanatory drawing of the capacity | capacitance adjustment by a single stage type reciprocating compressor. 台数制御装置の構成図である。It is a block diagram of a number control apparatus. 本開示の実施形態による、レシプロ圧縮機の台数制御方法の全体フロー図である。It is a whole flow figure of the number control method of a reciprocating compressor by an embodiment of this indication. 容量調整装置の構成図である。It is a block diagram of a capacity | capacitance adjustment apparatus. 本開示の実施形態による、レシプロ圧縮機の容量調整方法の全体フロー図である。1 is an overall flow diagram of a capacity adjustment method for a reciprocating compressor according to an embodiment of the present disclosure. 総ガス流量Gと運転容量Wの関係を示す説明図である。It is explanatory drawing which shows the relationship between the total gas flow volume G and the operating capacity W.
 以下、本開示の実施形態を添付図面に基づいて詳細に説明する。なお、各図において共通する部分には同一の符号を付し、重複した説明を省略する。 Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.
 以下、本開示において、「流量」とは、特に明記しない限り「重量流量」を意味する。また、「定格最大流量」とは、機器毎に予め設定された「最大流量」(すなわち最大重量流量)を意味する。
 「台数制御」とは、運転台数を変化させる制御を意味する。運転台数は、運転中において最小値が1の整数である。
 「容量調整」とは、運転中のレシプロ圧縮機の運転容量を変化させる制御を意味する。「運転容量」とは、運転中のレシプロ圧縮機が圧縮可能なガスの重量流量である。
 従って、レシプロ圧縮機の「最大運転容量」は、「定格最大流量」を意味する。
Hereinafter, in the present disclosure, “flow rate” means “weight flow rate” unless otherwise specified. The “rated maximum flow rate” means a “maximum flow rate” (that is, a maximum weight flow rate) preset for each device.
“Number control” means control for changing the number of operating units. The number of operating units is an integer having a minimum value of 1 during operation.
“Capacity adjustment” means control for changing the operating capacity of an operating reciprocating compressor. The “operating capacity” is the weight flow rate of gas that can be compressed by the reciprocating compressor in operation.
Therefore, the “maximum operating capacity” of the reciprocating compressor means “rated maximum flow rate”.
 図1は、本開示の実施形態によるBOG圧縮設備の全体系統図である。
 この図において、1はLNG、LEG、LPGなどの低温液化ガス、2は貯蔵タンク、3は低温液化ガス1の供給ライン、4はポンプ、5は蒸発器、6はガス移送ライン、7は合流管、8は需要先である。
FIG. 1 is an overall system diagram of a BOG compression facility according to an embodiment of the present disclosure.
In this figure, 1 is a low-temperature liquefied gas such as LNG, LEG, LPG, 2 is a storage tank, 3 is a supply line for low-temperature liquefied gas 1, 4 is a pump, 5 is an evaporator, 6 is a gas transfer line, and 7 is a merge Tube 8 is a customer.
 この構成により、貯蔵タンク2に貯蔵された低温液化ガス1を、供給ライン3によりポンプ4に供給し、ポンプ4で低温液化ガス1を加圧し、蒸発器5で低温液化ガス1を蒸発させ、蒸発したガス(例えば天然ガス)を需要先8に供給することができる。 With this configuration, the low-temperature liquefied gas 1 stored in the storage tank 2 is supplied to the pump 4 by the supply line 3, the low-temperature liquefied gas 1 is pressurized by the pump 4, and the low-temperature liquefied gas 1 is evaporated by the evaporator 5. The evaporated gas (for example, natural gas) can be supplied to the customer 8.
 需要先8は、例えば発電所であり、ボイラやガスタービンの燃料として例えば4~6MPaの圧力(以下、「高圧」と呼ぶ)の低温液化ガス1が需要先8に供給される。 The customer 8 is, for example, a power plant, and low temperature liquefied gas 1 having a pressure of 4 to 6 MPa (hereinafter referred to as “high pressure”) is supplied to the customer 8 as fuel for a boiler or a gas turbine.
 本実施形態のBOG圧縮設備は、第1制御装置10、第1圧力検出器11、複数の第1レシプロ圧縮機12、複数の第2レシプロ圧縮機14、中間配管16、定格最大流量検出器18、及び第2制御装置20を備える。
 なお、第1制御装置10、定格最大流量検出器18、及び第2制御装置20を単一の制御装置(例えばコンピュータ)で構成してもよい。
The BOG compression facility of the present embodiment includes a first control device 10, a first pressure detector 11, a plurality of first reciprocating compressors 12, a plurality of second reciprocating compressors 14, an intermediate pipe 16, and a rated maximum flow rate detector 18. And a second control device 20.
In addition, you may comprise the 1st control apparatus 10, the rated maximum flow volume detector 18, and the 2nd control apparatus 20 with a single control apparatus (for example, computer).
 貯蔵タンク2内で発生するBOGの圧力は低圧(例えば、常圧~0.02MPa)である。以下、貯蔵タンク2内で発生するBOGの圧力を「第0圧P0」と呼ぶ。 The pressure of BOG generated in the storage tank 2 is low (for example, normal pressure to 0.02 MPa). Hereinafter, the pressure of BOG generated in the storage tank 2 is referred to as “the 0th pressure P0”.
 図1において、貯蔵タンク2の上部と第1レシプロ圧縮機12の吸入側とはBOG払出しライン15で連結されている。
 複数の第1レシプロ圧縮機12は、並列に配置され、それぞれBOG払出しライン15を介して貯蔵タンク2で発生したBOGを吸引し、第1圧P1まで圧縮する。第1圧P1は、中圧(例えば1~3MPa)である。
 第1レシプロ圧縮機12の台数は、この図では5台であるが、2~4台でも6台以上でもよい。
In FIG. 1, the upper part of the storage tank 2 and the suction side of the first reciprocating compressor 12 are connected by a BOG discharge line 15.
The plurality of first reciprocating compressors 12 are arranged in parallel and each sucks BOG generated in the storage tank 2 through the BOG discharge line 15 and compresses it to the first pressure P1. The first pressure P1 is an intermediate pressure (for example, 1 to 3 MPa).
The number of first reciprocating compressors 12 is five in this figure, but may be two to four or six or more.
 第1圧力検出器11は、貯蔵タンク2の上部、又はBOG払出しライン15に設けられ、貯蔵タンク2で発生するBOGの圧力(第0圧P0)を検出する。
 第1制御装置10は、例えばコンピュータ(PC)であり、第1圧力検出器11で検出したBOGの圧力データを受信する。第1制御装置10は、受信した圧力データに基づいて、第0圧P0が予め設定した圧力範囲(例えば、常圧~0.02MPa)になるように、複数の第1レシプロ圧縮機12を制御する。
The first pressure detector 11 is provided in the upper part of the storage tank 2 or in the BOG discharge line 15 and detects the pressure of the BOG (the 0th pressure P0) generated in the storage tank 2.
The first control device 10 is, for example, a computer (PC), and receives BOG pressure data detected by the first pressure detector 11. Based on the received pressure data, the first controller 10 controls the plurality of first reciprocating compressors 12 so that the zeroth pressure P0 falls within a preset pressure range (for example, normal pressure to 0.02 MPa). To do.
 上述した第1レシプロ圧縮機12の起動と停止にかかる時間は、例えば30~60秒である。しかし、貯蔵タンク2の上部の空間容積は、中間配管16の容積に比較して非常に大きい(例えば中間配管16の容積の20~100倍)ので、第1圧力検出器11で圧力を検出した後に第1レシプロ圧縮機12を起動又は停止しても、貯蔵タンク2の圧力変動に追従することができる。
 従って、第1制御装置10と第1圧力検出器11により、貯蔵タンク2の上部圧力を予め設定した圧力範囲に維持することができる。
The time taken to start and stop the first reciprocating compressor 12 is, for example, 30 to 60 seconds. However, since the space volume in the upper part of the storage tank 2 is very large compared to the volume of the intermediate pipe 16 (for example, 20 to 100 times the volume of the intermediate pipe 16), the pressure is detected by the first pressure detector 11. Even if the first reciprocating compressor 12 is started or stopped later, the pressure fluctuation in the storage tank 2 can be followed.
Therefore, the upper pressure of the storage tank 2 can be maintained within a preset pressure range by the first control device 10 and the first pressure detector 11.
 図1において、複数の第2レシプロ圧縮機14は、並列に配置され、それぞれ第1レシプロ圧縮機12で圧縮された第1圧P1のBOGを第2圧P2まで圧縮する。第2圧P2は、需要先8(例えば発電所)に合わせた高圧(例えば4~6MPa)であることが好ましい。
 第2レシプロ圧縮機14の台数は、中間配管16から供給されるBOGの全量を圧縮できるように設定される。なお、第2レシプロ圧縮機14の台数は、この図では3台であるが、2台でも4台以上でもよい。
In FIG. 1, the plurality of second reciprocating compressors 14 are arranged in parallel and each compresses the BOG of the first pressure P1 compressed by the first reciprocating compressor 12 to the second pressure P2. The second pressure P2 is preferably a high pressure (eg, 4 to 6 MPa) that matches the customer 8 (eg, a power plant).
The number of second reciprocating compressors 14 is set so that the entire amount of BOG supplied from the intermediate pipe 16 can be compressed. The number of second reciprocating compressors 14 is three in this figure, but may be two or four or more.
 中間配管16は、複数の第1レシプロ圧縮機12の吐出側と複数の第2レシプロ圧縮機14の吸入側とを連通するガス配管である。
 中間配管16の容積は、貯蔵タンク2の上部の空間容積と比較すると非常に小さく、例えば貯蔵タンク2の空間容積の1~5%程度である。しかし、本実施形態はこの容積に限定されず、例えば中間配管16にガスリザーバを設けてもよい。
The intermediate pipe 16 is a gas pipe that communicates the discharge side of the plurality of first reciprocating compressors 12 and the suction side of the plurality of second reciprocating compressors 14.
The volume of the intermediate pipe 16 is very small as compared with the space volume above the storage tank 2, for example, about 1 to 5% of the space volume of the storage tank 2. However, the present embodiment is not limited to this volume, and for example, a gas reservoir may be provided in the intermediate pipe 16.
 この例において、中間配管16には、第1レシプロ圧縮機12以外のプロセス9からもオフガスが流入する。オフガスは、BOGと実質的に同一組成であるのがよい。
 ここでプロセス9とは、低温液化ガス1の貯蔵システムによりオフガスを発生するプロセスや設備を意味する。
 なおプロセス9は、本実施形態のBOG圧縮設備内のプロセスに限定されず、オフガス(例えばBOG)が発生する限りで、他のプロセスや設備であってもよい。また、プロセス9はこの例では1箇所のみであるが、2箇所以上であってもよい。
In this example, off-gas flows into the intermediate pipe 16 from processes 9 other than the first reciprocating compressor 12. The off gas should have substantially the same composition as BOG.
Here, the process 9 means a process or equipment for generating off-gas by the storage system for the low-temperature liquefied gas 1.
In addition, the process 9 is not limited to the process in the BOG compression equipment of this embodiment, Other processes and equipment may be sufficient as long as off-gas (for example, BOG) generate | occur | produces. Further, the process 9 is only one place in this example, but may be two places or more.
 複数の第2レシプロ圧縮機14の吐出側は、高圧ガスライン17を介して上述した合流管7に連結されている。
 上述した構成により、複数の第1レシプロ圧縮機12により、貯蔵タンク2で発生したBOGを中圧の第1圧P1まで圧縮し、複数の第2レシプロ圧縮機14により、第1圧P1のBOGを高圧の第2圧P2まで圧縮することができる。第2圧P2まで圧縮されたBOGは、合流管7で蒸発器5からのガスと合流し、需要先8に供給される。
The discharge sides of the plurality of second reciprocating compressors 14 are connected to the junction pipe 7 described above via high-pressure gas lines 17.
With the above-described configuration, the plurality of first reciprocating compressors 12 compress the BOG generated in the storage tank 2 to the first intermediate pressure P1, and the plurality of second reciprocating compressors 14 compress the BOG having the first pressure P1. Can be compressed to a high second pressure P2. The BOG compressed to the second pressure P <b> 2 merges with the gas from the evaporator 5 in the merge pipe 7 and is supplied to the customer 8.
 定格最大流量検出器18は、複数箇所から中間配管16に流入し得るBOGの定格最大流量をそれぞれ検出する。
 ここで複数箇所とは、運転中の第1レシプロ圧縮機12である。運転中の第1レシプロ圧縮機12の台数は、第2制御装置20による運転台数の制御信号に基づいた台数となる。また、プロセス9が存在する場合、上述の複数箇所はプロセス9をさらに含んでもよい。この場合、プロセス9から中間配管16に流入し得るBOGの定格最大流量は予め既知であり、第1制御装置10、第2制御装置20、又は定格最大流量検出器18の記憶装置(図示せず)に記憶されている。
 また、「流入し得る」とは、実際に流入する必要はなく、流入できればよいことを意味する。
The rated maximum flow rate detector 18 detects the rated maximum flow rate of the BOG that can flow into the intermediate pipe 16 from a plurality of locations.
Here, the plurality of locations are the first reciprocating compressor 12 in operation. The number of first reciprocating compressors 12 in operation is the number based on the control signal of the number of operating units by the second control device 20. Moreover, when the process 9 exists, the above-mentioned plurality of locations may further include the process 9. In this case, the rated maximum flow rate of BOG that can flow into the intermediate pipe 16 from the process 9 is known in advance, and the storage device (not shown) of the first control device 10, the second control device 20, or the rated maximum flow rate detector 18. ) Is stored.
Further, “can flow in” means that it is not necessary to actually flow in, and it is sufficient that it can flow in.
 第1レシプロ圧縮機12の定格最大流量は、運転容量Wが調整可能な場合には最大運転容量である。また、プロセス9の定格最大流量は、プロセス9からの流入量が変動する場合にはその最大値である。 The rated maximum flow rate of the first reciprocating compressor 12 is the maximum operating capacity when the operating capacity W is adjustable. The rated maximum flow rate of the process 9 is the maximum value when the inflow amount from the process 9 varies.
 図1において、中間配管16には、総ガス流量検出器13と第2圧力検出器19が設けられている。
 総ガス流量検出器13は、中間配管16に流入する総ガス流量G(すなわち実際に流入する重量流量)を検出し、第2制御装置20に出力する。
 第2圧力検出器19は、中間配管16内のBOGの圧力を検出し、第2制御装置20に出力する。
In FIG. 1, the intermediate pipe 16 is provided with a total gas flow rate detector 13 and a second pressure detector 19.
The total gas flow rate detector 13 detects the total gas flow rate G flowing into the intermediate pipe 16 (that is, the weight flow rate actually flowing in), and outputs it to the second control device 20.
The second pressure detector 19 detects the pressure of the BOG in the intermediate pipe 16 and outputs it to the second control device 20.
 第2制御装置20は、台数制御装置20aと容量調整装置20bを有する。 The second control device 20 includes a number control device 20a and a capacity adjustment device 20b.
 台数制御装置20aは、上述した複数箇所(運転中の第1レシプロ圧縮機12、または、運転中の第1レシプロ圧縮機12とプロセス9)からの定格最大流量に基づき、第2レシプロ圧縮機14の運転台数を制御する。この運転台数は、中間配管16から供給されるBOGの全量を圧縮できるように設定される。 The number control device 20a is based on the rated maximum flow rate from the plurality of locations (the first reciprocating compressor 12 being operated, or the first reciprocating compressor 12 being operated and the process 9), as described above. Control the number of operating units. The number of operating units is set so that the entire amount of BOG supplied from the intermediate pipe 16 can be compressed.
 容量調整装置20bは、中間配管16に流入する総ガス流量Gに基づき、運転中の各第2レシプロ圧縮機14の運転容量Wを調整する。 The capacity adjusting device 20b adjusts the operating capacity W of each second reciprocating compressor 14 during operation based on the total gas flow rate G flowing into the intermediate pipe 16.
 例えば第2レシプロ圧縮機14の運転容量Wが調整可能である場合、運転中の第2レシプロ圧縮機14の運転容量Wを調整し、その総和が、中間配管16に流入する総ガス流量Gよりも大きくなるように制御する。 For example, when the operating capacity W of the second reciprocating compressor 14 can be adjusted, the operating capacity W of the second reciprocating compressor 14 in operation is adjusted, and the sum is obtained from the total gas flow rate G flowing into the intermediate pipe 16. Is also controlled to be larger.
 図1において、本実施形態のBOG圧縮設備はさらに、リサイクルライン21と戻しガス流量制御弁22を備える。 1, the BOG compression facility of this embodiment further includes a recycle line 21 and a return gas flow rate control valve 22.
 リサイクルライン21は、第2レシプロ圧縮機14をバイパスしてその吐出側と中間配管16を連通する配管ラインである。この例において、リサイクルライン21は、上述した高圧ガスライン17と中間配管16を直接連通しているが、第2レシプロ圧縮機14における、その吐出側と吸入側を直接連通してもよい。
 また、リサイクルライン21は、1本に限定されず、2以上であってもよい。
The recycle line 21 is a piping line that bypasses the second reciprocating compressor 14 and communicates the discharge side with the intermediate piping 16. In this example, the recycle line 21 directly communicates the high-pressure gas line 17 and the intermediate pipe 16 described above, but the discharge side and the suction side of the second reciprocating compressor 14 may be directly communicated.
Moreover, the recycling line 21 is not limited to one, and may be two or more.
 戻しガス流量制御弁22は、リサイクルライン21に設けられ、第2レシプロ圧縮機14の吐出側から中間配管16に戻るガス流量を制御する。この制御は、第2圧力検出器19で検出した中間配管16の圧力が予め設定した圧力範囲(例えば、第1圧P1±α、αは任意の圧力)になるように設定するのがよい。
 なお、第2圧力検出器19を省略し、戻しガス流量制御弁22としてパイロット制御弁を用い、第2制御装置20を介することなく、中間配管16の圧力(パイロット圧)で戻しガス流量制御弁22を直接制御してもよい。
The return gas flow rate control valve 22 is provided in the recycle line 21 and controls the gas flow rate returning from the discharge side of the second reciprocating compressor 14 to the intermediate pipe 16. This control is preferably set so that the pressure of the intermediate pipe 16 detected by the second pressure detector 19 falls within a preset pressure range (for example, the first pressure P1 ± α and α are arbitrary pressures).
The second pressure detector 19 is omitted, a pilot control valve is used as the return gas flow rate control valve 22, and the return gas flow rate control valve is set at the pressure of the intermediate pipe 16 (pilot pressure) without going through the second control device 20. 22 may be directly controlled.
 複数の第2レシプロ圧縮機14により処理されるガス流量(重量流量)が中間配管16に流入するガス流量(重量流量)より多い場合でも、上述したリサイクルライン21と戻しガス流量制御弁22によって、中間配管16の圧力を予め設定した圧力範囲に制御することができる。 Even when the gas flow rate (weight flow rate) processed by the plurality of second reciprocating compressors 14 is larger than the gas flow rate (weight flow rate) flowing into the intermediate pipe 16, the above-described recycle line 21 and the return gas flow rate control valve 22 The pressure in the intermediate pipe 16 can be controlled within a preset pressure range.
 また、上述した容量調整を行っても、中間配管16に流入するガス流量は、流出するガス流量より小さいため、流量のアンバランスが発生する。しかし、このアンバランスは上述したリサイクルライン21と戻しガス流量制御弁22によりなくすことができる。 Even if the capacity adjustment described above is performed, the flow rate of gas flowing into the intermediate pipe 16 is smaller than the flow rate of gas flowing out, so that flow rate imbalance occurs. However, this imbalance can be eliminated by the recycle line 21 and the return gas flow control valve 22 described above.
 図2Aと図2Bは、単段式レシプロ圧縮機の具体例を示す模式図である。 2A and 2B are schematic views showing a specific example of a single-stage reciprocating compressor.
 図2Aの1台の単段式レシプロ圧縮機は、2つのシリンダCが対向配置されており、単一の駆動源M(例えばモータ)で2つのピストンDを駆動し、各ピストンDの往復動により、合計4箇所でガスを圧縮する。
 また、各シリンダCには、圧縮ガスを吸入側に戻すアンロード弁Vが設けられており、各シリンダCの往復動による圧縮の一方又は両方をアンロード(無負荷)にできるようになっている。
 従って、図2Aの単段式レシプロ圧縮機は、4つのアンロード弁V(一部のみを示す)のオン/オフの組み合わせにより、運転容量Wを5段階に変更することができる。以下、この5段階の運転容量Wを、少ない方から、0、第1容量W1、第2容量W2、第3容量W3、第4容量W4と呼ぶ。第4容量W4は最大運転容量である。
In the single-stage reciprocating compressor of FIG. 2A, two cylinders C are opposed to each other, and two pistons D are driven by a single drive source M (for example, a motor), and each piston D is reciprocated. Thus, gas is compressed at a total of four locations.
Each cylinder C is provided with an unload valve V that returns compressed gas to the suction side, and one or both of compressions by reciprocation of each cylinder C can be unloaded (no load). Yes.
Therefore, the single-stage reciprocating compressor of FIG. 2A can change the operating capacity W to five stages by the combination of on / off of the four unload valves V (only a part is shown). Hereinafter, these five stages of operation capacity W are referred to as 0, first capacity W1, second capacity W2, third capacity W3, and fourth capacity W4 from the smallest. The fourth capacity W4 is the maximum operating capacity.
 図2Bの1台の単段式レシプロ圧縮機は、4つのシリンダCが放射状に配置されており、単一の駆動源M(例えばモータ)で4つのピストンDを駆動し、各ピストンDにより、合計4箇所でガスを圧縮する。
 また、各シリンダCには、圧縮ガスを吸入側に戻すアンロード弁Vが設けられており、各シリンダCをアンロード(無負荷)にできるようになっている。
 従って、図2Bの単段式レシプロ圧縮機も、図2Aと同様に、4つのアンロード弁V(一部のみを示す)のオン/オフの組み合わせにより、運転容量Wを5段階に変更することができる。
In the single-stage reciprocating compressor of FIG. 2B, four cylinders C are arranged radially, and four pistons D are driven by a single driving source M (for example, a motor). The gas is compressed at a total of 4 points.
Each cylinder C is provided with an unload valve V for returning the compressed gas to the suction side so that each cylinder C can be unloaded (no load).
Therefore, the single stage reciprocating compressor of FIG. 2B also changes the operating capacity W to five stages by the combination of on / off of the four unload valves V (only a part is shown) as in FIG. 2A. Can do.
 なお、単段式レシプロ圧縮機の変更可能な容量のステップ数は、上述した5段に限定されず、2段(すなわちオン/オフのみ)でも、3,4段又は6段以上でもよい。 It should be noted that the number of variable capacity steps of the single-stage reciprocating compressor is not limited to the above-described five stages, and may be two stages (that is, only on / off), three, four stages, or six stages or more.
 第1レシプロ圧縮機12は、上述した単段式レシプロ圧縮機に限定されず、多段式レシプロ圧縮機であってもよい。また複数の第1レシプロ圧縮機12の最大運転容量は、同一でも相違してもよい。
 第2レシプロ圧縮機14は、上述した単段式レシプロ圧縮機であることが好ましい。また複数の第2レシプロ圧縮機14の最大運転容量は、同一でも相違してもよい。
The first reciprocating compressor 12 is not limited to the single-stage reciprocating compressor described above, and may be a multi-stage reciprocating compressor. The maximum operating capacities of the plurality of first reciprocating compressors 12 may be the same or different.
The second reciprocating compressor 14 is preferably the above-described single-stage reciprocating compressor. The maximum operating capacities of the plurality of second reciprocating compressors 14 may be the same or different.
 図3は、1台の単段式レシプロ圧縮機による容量調整の説明図である。この図は、容量が5段階に変更可能の場合の負荷率0,A1,A2,A3,100%と運転容量W及び処理流量との関係を示す図である。処理流量は、1台の単段式レシプロ圧縮機が処理するガス流量を意味する。図3において、記号gは、これに対応する運転容量W(すなわち、負荷率)になっている単段式レシプロ圧縮機が処理できる最大流量(以下、処理可能流量gという)を示す。この処理可能流量gは、対応する運転容量Wに等しい。
 この図に示すように、上述した4つのアンロード弁V(一部のみを示す)のオン/オフの組み合わせにより、負荷率0,A1,A2,A3,100%の各段に対応するように、運転容量Wを、0,W1,W2,W3,W4の5段階に調整することができる(この例では、いずれの隣接ステップ同士の容量差も、W1である)。負荷率0,A1,A2,A3,100%は例えば最大運転容量の0,25,50,75,100%である。
FIG. 3 is an explanatory diagram of capacity adjustment by one single-stage reciprocating compressor. This figure is a diagram showing the relationship between the load factor 0, A1, A2, A3, 100%, the operating capacity W, and the processing flow rate when the capacity can be changed in five stages. The processing flow rate means a gas flow rate processed by one single-stage reciprocating compressor. In FIG. 3, the symbol g indicates the maximum flow rate (hereinafter referred to as the processable flow rate g) that can be processed by the single-stage reciprocating compressor having the corresponding operating capacity W (that is, the load factor). This processable flow rate g is equal to the corresponding operating capacity W.
As shown in this figure, the combination of on / off of the above-described four unload valves V (only a part is shown) corresponds to each stage of load factor 0, A1, A2, A3, 100%. The operating capacity W can be adjusted in five stages of 0, W1, W2, W3, and W4 (in this example, the capacity difference between any adjacent steps is W1). The load factors 0, A1, A2, A3, and 100% are, for example, 0, 25, 50, 75, and 100% of the maximum operating capacity.
 図4は、台数制御装置20aの構成図である。
 台数制御装置20aは、例えばコンピュータ(PC)であり、記憶装置23、演算装置24、及び出力装置25を備える。
 記憶装置23は、RAM、ROM、ハードディスク、等のメモリである。
 演算装置24は、例えばCPUである。
 出力装置25は、例えば出力用端子、又は出力用リレーである。
FIG. 4 is a configuration diagram of the number control device 20a.
The number control device 20 a is, for example, a computer (PC), and includes a storage device 23, a calculation device 24, and an output device 25.
The storage device 23 is a memory such as a RAM, a ROM, or a hard disk.
The arithmetic device 24 is a CPU, for example.
The output device 25 is, for example, an output terminal or an output relay.
 本実施形態による、レシプロ圧縮機の制御方法は、第2制御装置20により実行される。この制御方法は、以下で述べる台数制御と容量調整を行うものである。ただし、容量調整は行わなくてもよく、この場合には、容量調整装置20bを省略してよい。 The control method for the reciprocating compressor according to the present embodiment is executed by the second control device 20. This control method performs unit control and capacity adjustment described below. However, the capacity adjustment may not be performed, and in this case, the capacity adjustment device 20b may be omitted.
(台数制御)
 台数制御装置20a、すなわち演算装置24は、最大総ガス流量予測部24a、指令台数計算部24b、及び指令出力部24cを有する。
(Unit control)
The number control device 20a, that is, the arithmetic device 24 includes a maximum total gas flow rate prediction unit 24a, a command number calculation unit 24b, and a command output unit 24c.
 図5は、本実施形態によるレシプロ圧縮機の台数制御方法の全体フロー図である。
 この図において、本実施形態の方法は、S1~S8の各ステップ(工程)からなる。
FIG. 5 is an overall flowchart of the method for controlling the number of reciprocating compressors according to this embodiment.
In this figure, the method of the present embodiment includes steps (steps) S1 to S8.
 ステップS1では、上述したBOG圧縮設備を準備する。
 ステップS2では、定格最大流量検出器18により、複数箇所から中間配管16に流入し得るBOGの定格最大流量をそれぞれ検出する。
In step S1, the above-described BOG compression facility is prepared.
In step S2, the rated maximum flow rate detector 18 detects the rated maximum flow rate of BOG that can flow into the intermediate pipe 16 from a plurality of locations.
 ステップS3では、最大総ガス流量予測部24aにより、上述した複数箇所からの定格最大流量に基づいて最大総ガス流量Gmaxを予測する。
 上述した複数箇所は、運転中の第1レシプロ圧縮機12を含む。なお、運転していない(すなわち停止中の)第1レシプロ圧縮機12は対象外である。
 上述した複数箇所が、プロセス9をさらに含む場合には、ステップS3において、ステップS2で検出した各定格最大流量と、上述した記憶装置に記憶されているプロセス9の定格最大流量とに基づいて、最大総ガス流量予測部24aにより、最大総ガス流量Gmaxを予測する。
 例えば、5台の第1レシプロ圧縮機12のうち3台が運転中であり、それぞれの定格最大流量(すなわち最大運転容量)がG1,G2,G3であり、プロセス9の定格最大流量がG9である場合、最大総ガス流量Gmaxは、Gmax=G1+G2+G3+G9・・・(1)で求められる。
 ここで、第1レシプロ圧縮機12の運転容量Wが例えば上述した5段階に変更可能である場合、定格最大流量は第4容量W4を意味する。運転中の第1レシプロ圧縮機12の運転容量Wは、0,W1,W2,W3,W4のいずれであってもよい。
In step S3, the maximum total gas flow rate prediction unit 24a predicts the maximum total gas flow rate Gmax based on the rated maximum flow rates from the plurality of locations described above.
The plurality of locations described above include the first reciprocating compressor 12 in operation. In addition, the 1st reciprocating compressor 12 which is not drive | operating (namely, being stopped) is excluded.
When the plurality of locations described above further include the process 9, in step S3, based on each rated maximum flow rate detected in step S2 and the rated maximum flow rate of the process 9 stored in the storage device described above, The maximum total gas flow rate prediction unit 24a predicts the maximum total gas flow rate Gmax.
For example, three of the five first reciprocating compressors 12 are in operation, the rated maximum flow rates (that is, the maximum operating capacity) are G1, G2, and G3, and the rated maximum flow rate of the process 9 is G9. In some cases, the maximum total gas flow rate Gmax is obtained by Gmax = G1 + G2 + G3 + G9 (1).
Here, when the operating capacity W of the first reciprocating compressor 12 can be changed to, for example, the above-described five stages, the rated maximum flow rate means the fourth capacity W4. The operating capacity W of the first reciprocating compressor 12 during operation may be any of 0, W1, W2, W3, and W4.
 ステップS4では、指令台数計算部24bにより、最大総ガス流量Gmaxから第2レシプロ圧縮機14の指令台数Nを計算する。
 すなわち、指令台数計算部24bは、最大総ガス流量Gmaxと各第2レシプロ圧縮機14の定格最大流量X(すなわち最大運転容量)とから、第2レシプロ圧縮機14の指令台数Nを計算する。
 例えば、第2レシプロ圧縮機14の指令台数Nは、N=ROUNDUP(Gmax/X)・・・(2)で求められる。関数「ROUNDUP」は、端数を切り上げて整数にすることを意味する。
In step S4, the command number calculation unit 24b calculates the command number N of the second reciprocating compressor 14 from the maximum total gas flow rate Gmax.
That is, the command number calculation unit 24b calculates the command number N of the second reciprocating compressor 14 from the maximum total gas flow rate Gmax and the rated maximum flow rate X (that is, the maximum operating capacity) of each second reciprocating compressor 14.
For example, the command number N of the second reciprocating compressor 14 is obtained by N = ROUNDUP (Gmax / X) (2). The function “ROUNDUP” means rounding up to an integer.
 複数の第2レシプロ圧縮機14の定格最大流量X1,X2,X3が相違しており、各第2レシプロ圧縮機14に優先度が設定されている場合には、指令台数計算部24bは、優先度の高い順に第2レシプロ圧縮機14を選択してよい。この時、選択した第2レシプロ圧縮機14の定格最大流量の合計が上述した最大総ガス流量Gmaxを超えるようにする。
 優先度は、運転効率、メンテナンス性、寿命等に基づいているのがよい。
When the rated maximum flow rates X1, X2, and X3 of the plurality of second reciprocating compressors 14 are different and priority is set for each second reciprocating compressor 14, the command number calculation unit 24b gives priority. The second reciprocating compressor 14 may be selected in descending order. At this time, the sum of the rated maximum flow rates of the selected second reciprocating compressor 14 is set to exceed the above-described maximum total gas flow rate Gmax.
The priority should be based on operating efficiency, maintainability, lifespan, and the like.
 上述した実施形態の台数制御方法により、運転中の第1レシプロ圧縮機12が定格最大流量(すなわち最大運転容量)で運転する場合でも、N台の第2レシプロ圧縮機14の定格最大流量の合計は、上述した最大総ガス流量Gmaxを超える。従って、中間配管16から供給されるBOGの全量をN台の第2レシプロ圧縮機14で圧縮することができる。 Even when the first reciprocating compressor 12 in operation operates at the rated maximum flow rate (that is, the maximum operating capacity) by the number control method of the above-described embodiment, the total of the maximum rated flow rates of the N second reciprocating compressors 14 Exceeds the above-mentioned maximum total gas flow rate Gmax. Accordingly, the entire amount of BOG supplied from the intermediate pipe 16 can be compressed by the N second reciprocating compressors 14.
 ステップS5~S8では、指令出力部24cにより、運転中の第2レシプロ圧縮機14の現在の運転台数N2と計算による指令台数Nとを比較し、運転中の運転台数N2が計算による指令台数Nと一致するように(又は、運転台数N2が指定台数Nに近づくように)運転台数N2の増加又は減少を指令する。 In steps S5 to S8, the command output unit 24c compares the current operating number N2 of the operating second reciprocating compressor 14 with the calculated commanded number N, and the operating operating number N2 is calculated. Is commanded to increase or decrease the operating number N2 (or so that the operating number N2 approaches the designated number N).
 すなわち、指令出力部24cは、ステップS5において、指令台数Nが運転台数N2を超える場合(YES)に、ステップS6において、運転台数N2を増やす増台指令を出力する。この増台指令により、第2レシプロ圧縮機14の運転台数N2は、N2+1に変更される。
 増台指令を出力した後は、ステップS3に戻る。
That is, when the command number N exceeds the operating number N2 (YES) in step S5, the command output unit 24c outputs a command to increase the number of operating units N2 in step S6. Due to this increase command, the number N2 of the second reciprocating compressors 14 is changed to N2 + 1.
After outputting the additional command, the process returns to step S3.
 また、指令出力部24cは、ステップS7において、現在の運転台数N2より1台少ない台数が指令台数Nを超える場合(YES)に、ステップS8において、運転台数N2を減らす減台指令を出力する。この減台指令により、第2レシプロ圧縮機14の運転台数N2は、N2-1に変更される。
 減台指令を出力した後は、ステップS3に戻る。
Further, in step S7, the command output unit 24c outputs a reduction command for reducing the operating number N2 in step S8 when the number of units less than the current operating number N2 exceeds the command number N (YES). With this command to reduce the number of units, the number N2 of the second reciprocating compressors 14 is changed to N2-1.
After outputting the reduction command, the process returns to step S3.
 ステップS5,S7でNOの場合は、増台指令も減台指令も出力せず、第2レシプロ圧縮機14の運転台数N2は、変更なく維持される。 If NO in steps S5 and S7, neither an increase command nor a decrease command is output, and the number N2 of the second reciprocating compressors 14 is maintained without change.
 上述したステップS5~S8により、運転中の運転台数N2を計算による指令台数Nに一致させることができる。この結果、運転中の第1レシプロ圧縮機12が定格最大流量(すなわち最大運転容量)で運転する場合でも、N台の第2レシプロ圧縮機14の定格最大流量の合計は、上述した最大総ガス流量Gmaxを超え、中間配管16から供給されるBOGの全量を圧縮することができる。 By the steps S5 to S8 described above, the operating number N2 in operation can be made to coincide with the commanded number N calculated. As a result, even when the first reciprocating compressor 12 in operation is operated at the rated maximum flow rate (that is, the maximum operating capacity), the total of the maximum rated flow rates of the N second reciprocating compressors 14 is the maximum total gas described above. Exceeding the flow rate Gmax, the entire amount of BOG supplied from the intermediate pipe 16 can be compressed.
(容量調整)
 第2レシプロ圧縮機14が、の運転容量は、互いに異なる2以上の運転容量にステップ状に調整可能である場合に、容量調整装置20bは、以下の(1)と(2)の一方または両方を行う。
 (1)運転中の複数の第2レシプロ圧縮機14への総ガス流量G(すなわち、中間配管16を流れる総ガス流量G)が、運転中である各第2レシプロ圧縮機14の現在の運転容量(すなわち、処理可能流量g)の総和Wsを超えたら、運転中である複数の第2レシプロ圧縮機14の少なくともいずれかの運転容量を、最大運転容量側へ切り替える。
 (2)上記総ガス流量Gが、運転中の各第2レシプロ圧縮機14の現在の運転容量の総和Wsよりも小さく、かつ、上記総和Wsから総ガス流量Gを引いた値(Ws-G)が、第2レシプロ圧縮機14の運転容量の切り替え可能量(すなわち、図3のように運転容量が1段だけステップ状に切り替わる量)よりも大きい場合に、運転中の各第2レシプロ圧縮機14の運転容量をゼロより大きい値に維持しつつ、運転中である複数の第2レシプロ圧縮機14の少なくともいずれかの運転容量を最小運転容量側へ切り替える。
(Capacity adjustment)
When the operating capacity of the second reciprocating compressor 14 can be adjusted stepwise to two or more operating capacities different from each other, the capacity adjusting device 20b has one or both of the following (1) and (2). I do.
(1) The current operation of each second reciprocating compressor 14 in which the total gas flow rate G to the plurality of second reciprocating compressors 14 in operation (that is, the total gas flow rate G flowing through the intermediate pipe 16) is in operation. When the total sum Ws of the capacities (that is, the processable flow rate g) is exceeded, at least one of the operating capacities of the plurality of second reciprocating compressors 14 being operated is switched to the maximum operating capacity side.
(2) The total gas flow rate G is smaller than the total current operating capacity Ws of each second reciprocating compressor 14 in operation, and a value obtained by subtracting the total gas flow rate G from the total Ws (Ws−G ) Is larger than the switchable amount of the operation capacity of the second reciprocating compressor 14 (that is, the operation capacity is switched in steps of one stage as shown in FIG. 3), each second reciprocal compression during operation The operating capacity of the plurality of second reciprocating compressors 14 in operation is switched to the minimum operating capacity side while maintaining the operating capacity of the machine 14 at a value greater than zero.
 すなわち、容量調整装置20bは、運転中である各第2レシプロ圧縮機14における図3の運転容量(処理可能流量g)の総和が、運転中の複数の第2レシプロ圧縮機14への総ガス流量Gを超えるように設定する。
 本実施形態では、上述した台数制御装置20aが行った台数制御により運転中となっている複数の第2レシプロ圧縮機14の一部または全部に対して、容量調整装置20bによる容量調整が行われる。
That is, the capacity adjusting device 20b is configured such that the total operation capacity (processable flow rate g) of FIG. 3 in each second reciprocating compressor 14 in operation is the total gas to the plurality of second reciprocating compressors 14 in operation. Set to exceed flow rate G.
In the present embodiment, the capacity adjustment by the capacity adjustment device 20b is performed on some or all of the plurality of second reciprocating compressors 14 that are operating by the number control performed by the number control device 20a described above. .
 図6は、容量調整装置20bの構成図である。
 容量調整装置20bは、例えばコンピュータ(PC)であり、記憶装置33、演算装置34、及び出力装置35を備える。
 記憶装置33は、RAM、ROM、ハードディスク、等のメモリである。
 演算装置34は、例えばCPUである。
 出力装置35は、例えば出力用端子、又は出力用リレーである。
FIG. 6 is a configuration diagram of the capacity adjustment device 20b.
The capacity adjustment device 20b is, for example, a computer (PC), and includes a storage device 33, a calculation device 34, and an output device 35.
The storage device 33 is a memory such as a RAM, a ROM, or a hard disk.
The computing device 34 is a CPU, for example.
The output device 35 is, for example, an output terminal or an output relay.
 容量調整装置20b、すなわち演算装置34は、第1容量調整部34aと第2容量調整部34bを有する。 The capacity adjustment device 20b, that is, the calculation device 34 includes a first capacity adjustment unit 34a and a second capacity adjustment unit 34b.
 図7は、本実施形態によるレシプロ圧縮機の容量調整方法の全体フロー図である。
 この図において、本実施形態の方法は、S11~S18の各ステップ(工程)からなる。
FIG. 7 is an overall flowchart of the capacity adjustment method for the reciprocating compressor according to the present embodiment.
In this figure, the method of the present embodiment includes steps (steps) S11 to S18.
 ステップS11では、上述したBOG圧縮設備を準備する。
 ステップS12では、総ガス流量検出器13により、中間配管16に実際に流入する総ガス流量Gを検出する。
In step S11, the above-described BOG compression facility is prepared.
In step S <b> 12, the total gas flow rate detector 13 detects the total gas flow rate G actually flowing into the intermediate pipe 16.
 ステップS13~S18は、本実施形態による、レシプロ圧縮機の容量調整方法を示している。以下、この容量調整を説明する。 Steps S13 to S18 show the capacity adjustment method of the reciprocating compressor according to this embodiment. Hereinafter, this capacity adjustment will be described.
 容量調整装置20bは、運転中の第2レシプロ圧縮機14が1台である場合に、図3に示すような運転容量W(すなわち、処理可能流量g)が、中間配管16を実際に流れる総ガス流量Gを超えるように運転容量Wを設定する。 When the number of second reciprocating compressors 14 that are in operation is one, the capacity adjusting device 20b has an operating capacity W (that is, a processable flow rate g) as shown in FIG. The operating capacity W is set so as to exceed the gas flow rate G.
 また、運転中の第2レシプロ圧縮機14が2台以上である場合には、運転中の第2レシプロ圧縮機14の運転容量Wの総和が、中間配管16に実際に流入する総ガス流量Gを超えるように、運転中の各第2レシプロ圧縮機14の運転容量Wを設定する。
 例えば、2台以上が運転中で優先順位がない場合には、中間配管16に実際に流入する総ガス流量Gに対して、各第2レシプロ圧縮機14が分担する運転容量W(処理可能流量g)を適宜設定し、N台の運転容量W(図3を参照)の総和が総ガス流量Gを超えるように設定する。
When there are two or more second reciprocating compressors 14 in operation, the total operating flow W of the second reciprocating compressor 14 in operation is the total gas flow rate G actually flowing into the intermediate pipe 16. The operating capacity W of each second reciprocating compressor 14 during operation is set so as to exceed.
For example, when two or more units are operating and there is no priority, the operation capacity W (processable flow rate) shared by each second reciprocating compressor 14 with respect to the total gas flow rate G actually flowing into the intermediate pipe 16. g) is set as appropriate, and is set so that the sum of the N operating capacities W (see FIG. 3) exceeds the total gas flow rate G.
 容量調整装置20bは、運転中の第2レシプロ圧縮機14がN台(N≧2)であり、優先順位がある場合には、以下のすべての条件を満たすように運転中の各第2レシプロ圧縮機14の運転容量Wを調整する。
 (A)運転中の第2レシプロ圧縮機14の運転容量Wの総和が、中間配管16に流入する総ガス流量Gを超える。
 (B)第2レシプロ圧縮機14の負荷率が、優先順位の高い順に高い。すなわち、運転中の複数の第2レシプロ圧縮機14にそれぞれ優先順位が予め設定されており、優先順位が高い第2レシプロ圧縮機14ほど高い運転容量(負荷率)を有する。
 (C)運転中のすべての第2レシプロ圧縮機14の運転容量(負荷率)が、ゼロより大きい。
 なお優先度は、運転効率、メンテナンス性、寿命等に基づくのがよい。
When the number of second reciprocating compressors 14 in operation is N (N ≧ 2) and there is a priority order, the capacity adjusting device 20b has each second reciprocating device 14 in operation so as to satisfy all the following conditions. The operating capacity W of the compressor 14 is adjusted.
(A) The total operation capacity W of the second reciprocating compressor 14 in operation exceeds the total gas flow rate G flowing into the intermediate pipe 16.
(B) The load factor of the second reciprocating compressor 14 is higher in descending order of priority. That is, priorities are set in advance for the plurality of second reciprocating compressors 14 in operation, and the second reciprocating compressor 14 having a higher priority has a higher operating capacity (load factor).
(C) The operating capacity (load factor) of all the second reciprocating compressors 14 in operation is greater than zero.
The priority should be based on operating efficiency, maintainability, life, etc.
 この構成により、以下の効果が得られる。
 (A)により、中間配管16に流入する総ガス流量Gよりも、運転中の第2レシプロ圧縮機14の運転容量Wの総和が大きいため、中間配管16の圧力上昇を防止することができる。
 なお、運転中の第2レシプロ圧縮機14の運転容量Wの総和の方が大きいため、中間配管16の圧力は減圧していくが、リサイクルライン21及び戻りガス流量制御弁22があるため負圧化を防止することができる。
 (B)により、優先度(例えば運転効率)の高い第2レシプロ圧縮機14の負荷率を高くして、全体の運転効率などを高めることができる。
 (C)により、第2レシプロ圧縮機14が、ゼロの運転容量で運転されることを防止し、第2レシプロ圧縮機14の運転性能を維持することができる。
With this configuration, the following effects can be obtained.
By (A), since the sum total of the operation capacity W of the 2nd reciprocating compressor 14 in operation is larger than the total gas flow rate G which flows into the intermediate pipe 16, the pressure rise of the intermediate pipe 16 can be prevented.
Since the total operation capacity W of the second reciprocating compressor 14 in operation is larger, the pressure in the intermediate pipe 16 is reduced. However, since the recycle line 21 and the return gas flow control valve 22 are provided, the negative pressure is increased. Can be prevented.
By (B), the load factor of the 2nd reciprocating compressor 14 with high priority (for example, operation efficiency) can be made high, and the whole operation efficiency etc. can be raised.
By (C), it can prevent that the 2nd reciprocating compressor 14 is drive | operated by zero operation capacity, and can maintain the driving | running performance of the 2nd reciprocating compressor 14. FIG.
 図8は、総ガス流量Gと運転容量Wの関係を示す説明図である。
 この図において、左側は中間配管16に流入する総ガス流量G、右側は運転中の3台の第2レシプロ圧縮機14の運転容量Wを示している。
 また右側の3台は、上から1番目の優先順位Kが1番であり、2番目が2番、3番目が3番である。右側の斜線部は実際のガス流量、空白部は運転容量Wのうちアンロード分を意味している。
 図8の各第2レシプロ圧縮機14の運転容量Wは、0,W1,W2=2W1,W3=3W1,W4=4W1の5段階に変更可能である。
FIG. 8 is an explanatory diagram showing the relationship between the total gas flow rate G and the operating capacity W.
In this figure, the left side shows the total gas flow rate G flowing into the intermediate pipe 16, and the right side shows the operating capacity W of the three second reciprocating compressors 14 in operation.
In the right three units, the first priority K from the top is No. 1, the second is No. 2, and the third is No. 3. The hatched portion on the right side indicates the actual gas flow rate, and the blank portion indicates the unloaded portion of the operating capacity W.
The operating capacity W of each second reciprocating compressor 14 in FIG. 8 can be changed in five stages: 0, W1, W2 = 2W1, W3 = 3W1, W4 = 4W1.
 この例において、上から1番目の運転容量WがW4、2番目がW3、3番目がW1であり、W4+W3+W1>Gの関係を満たし、上記(A)の条件を満たしている。
 また、W4>W3>W1であり、上記(B)の条件を満たしている。
 さらに、W4,W3,W1≧W1であり、上記(C)の条件を満たしている。
In this example, the first operating capacity W from the top is W4, the second is W3, the third is W1, satisfies the relationship of W4 + W3 + W1> G, and satisfies the condition (A).
Further, W4>W3> W1, and the condition (B) is satisfied.
Further, W4, W3, W1 ≧ W1, and the condition (C) is satisfied.
 以下、図7と図8を参照して、各第2レシプロ圧縮機14の運転容量Wの調整方法を具体的に説明する。 Hereinafter, with reference to FIG. 7 and FIG. 8, the adjustment method of the operation capacity W of each 2nd reciprocating compressor 14 is demonstrated concretely.
 図8に示すように、運転中の第2レシプロ圧縮機14が2台以上(この例では3台)である場合には、運転中の第2レシプロ圧縮機14の運転容量Wの総和が、中間配管16に実際に流入する総ガス流量Gを超えるように設定される。 As shown in FIG. 8, when there are two or more second reciprocating compressors 14 in operation (three in this example), the total operating capacity W of the second reciprocating compressor 14 in operation is The total gas flow rate G actually flowing into the intermediate pipe 16 is set to be exceeded.
 (1)また第1容量調整部34aにより、優先順位Kが1からN-1である場合に(ステップS13でYES)、優先順位Kの高い順に、各第2レシプロ圧縮機14の運転容量WをステップS14~S16で以下のように設定する。 (1) When the priority order K is from 1 to N-1 by the first capacity adjustment unit 34a (YES in step S13), the operating capacity W of each second reciprocating compressor 14 in descending order of the priority order K. Are set in steps S14 to S16 as follows.
 ステップS14において、第1容量調整部34aは、優先順位Kに対し、優先順位が1から(K-1)までの運転容量Wの和ΣWAを計算する。ΣWAは、計算中の優先順位Kよりも優先順位の高い第2レシプロ圧縮機14の運転容量Wの総和を意味する。
 例えば図8において、1番上の1台は優先順位が1番であり、それより優先順位の高いものがないため、1台目のΣWAは0である。また、上から2番目の1台は、優先順位が2番であり、それより優先順位の高い1台があるため、ΣWAは1台目の運転容量であるW4である。
In step S14, the first capacity adjustment unit 34a calculates the sum ΣWA of the operating capacities W from the priority order 1 to (K−1) with respect to the priority order K. ΣWA means the sum of the operating capacities W of the second reciprocating compressor 14 having a higher priority than the priority K being calculated.
For example, in FIG. 8, the first unit has the highest priority, and there is no higher priority, so the first ΣWA is zero. Further, since the second one from the top has the second highest priority and one higher priority, ΣWA is the first operating capacity W4.
 ステップS15において、第1容量調整部34aは、優先順位Kに対し、優先順位が(K+1)からNまでの最低容量(上述した第1容量W1)の和ΣWBを計算する。最低容量は、ゼロより大きい調整可能な最低容量である。ΣWBは、計算中の第2レシプロ圧縮機14よりも優先順位の低い第2レシプロ圧縮機14が全て最低容量であると仮定して計算されるものである。この仮定は、運転中の第2レシプロ圧縮機14の運転容量Wを最低容量以上に確保するためのものである。
 例えば図8において、1番上の1台は優先順位が1番であり、それより優先順位の低いものが2台あるため、1台目のΣWBは2W1である。また、上から2番目の1台は、優先順位が2番であり、それより優先順位の低いものが1台あるため、2台目のΣWBはW1である。
In step S15, the first capacity adjustment unit 34a calculates the sum ΣWB of the minimum capacities (the above-described first capacities W1) from (K + 1) to N with respect to the priority order K. The minimum capacity is an adjustable minimum capacity greater than zero. ΣWB is calculated on the assumption that all the second reciprocating compressors 14 having a lower priority than the second reciprocating compressor 14 being calculated have the minimum capacity. This assumption is for ensuring the operating capacity W of the second reciprocating compressor 14 during operation to be equal to or greater than the minimum capacity.
For example, in FIG. 8, the first unit has the highest priority, and there are two units with lower priority, so the first ΣWB is 2W1. Also, the second one from the top has the second priority, and there is one lower priority, so the second ΣWB is W1.
 ステップS16において、第1容量調整部34aは、優先順位Kに対しその運転容量Wを、総ガス流量Gから、ΣWAとΣWBとを減算した残容量に基づいて調整する。この残容量が、優先順位Kの第2レシプロ圧縮機14の最大運転容量以上である場合には、第1容量調整部34aは、この第2レシプロ圧縮機14の運転容量を最大運転容量に設定してよい。この残容量が、優先順位Kの第2レシプロ圧縮機14の最大運転容量より小さい場合には、例えば、第1容量調整部34aは、この第2レシプロ圧縮機14の運転容量を、残容量より大きく且つ残容量に最も近い運転容量に設定してよい。
 例えば図8において、1番上の1台は優先順位が1番であり、W>G-ΣWA-ΣWB=G-0-2W1を満たすWはW4を超える。この場合、運転容量WをW4に調整する。
 また、上から2番目の1台は、優先順位が2番であり、W>G-ΣWA-ΣWB=G-W4-W1を満たすWはW2を超えるがW3よりは少ない。この場合、運転容量WをW3に調整する。
In step S16, the first capacity adjustment unit 34a adjusts the operating capacity W with respect to the priority order K based on the remaining capacity obtained by subtracting ΣWA and ΣWB from the total gas flow rate G. When the remaining capacity is equal to or greater than the maximum operating capacity of the second reciprocating compressor 14 with priority K, the first capacity adjusting unit 34a sets the operating capacity of the second reciprocating compressor 14 to the maximum operating capacity. You can do it. When the remaining capacity is smaller than the maximum operating capacity of the second reciprocating compressor 14 with priority K, for example, the first capacity adjusting unit 34a determines the operating capacity of the second reciprocating compressor 14 from the remaining capacity. The operating capacity may be set large and closest to the remaining capacity.
For example, in FIG. 8, the top one has the highest priority, and W satisfying W> G−ΣWA−ΣWB = G−0−2W1 exceeds W4. In this case, the operating capacity W is adjusted to W4.
The second one from the top has the second highest priority, and W satisfying W> G−ΣWA−ΣWB = G−W4−W1 exceeds W2 but less than W3. In this case, the operating capacity W is adjusted to W3.
 上述した運転容量Wの調整により、優先順位の高い第2レシプロ圧縮機14の運転容量Wと、優先順位の低い第2レシプロ圧縮機14の、ゼロより大きい最低容量を確保した上で、計算中の第2レシプロ圧縮機14の運転容量Wを最大に設定することができる。 By adjusting the operating capacity W described above, the operating capacity W of the second reciprocating compressor 14 having a higher priority and the minimum capacity of the second reciprocating compressor 14 having a lower priority being secured are being calculated. The operating capacity W of the second reciprocating compressor 14 can be set to the maximum.
 (2)第2容量調整部34bにより、優先順位KがN(ステップS13でNO)の場合に、第2レシプロ圧縮機14の運転容量Wを以下のように設定する。 (2) The operating capacity W of the second reciprocating compressor 14 is set as follows by the second capacity adjusting unit 34b when the priority order K is N (NO in step S13).
 ステップS17において、第2容量調整部34bは、優先順位Nに対し、1台目から(N-1)台目までの運転容量Wの和ΣWCを計算する。ΣWCは、N台目の第2レシプロ圧縮機14よりも優先順位の高いすべての第2レシプロ圧縮機14の運転容量Wの総和を意味する。
 例えば図8において、3番上の1台は優先順位が3番であり、それより優先順位の低いものがないため、ΣWCはW4+W3である。
In step S17, the second capacity adjusting unit 34b calculates the sum ΣWC of the operating capacities W from the first to the (N−1) th for the priority N. ΣWC means the sum of the operating capacities W of all the second reciprocating compressors 14 having a higher priority than the N-th second reciprocating compressor 14.
For example, in FIG. 8, the one on the top of the third has the third priority, and there is no lower priority, so ΣWC is W4 + W3.
 ステップS18において、第2容量調整部34bは、N台目の運転容量Wを、総ガス流量GからΣWCを減算した残容量よりも大きい値に調整する。例えば、第2容量調整部34bは、N台目の運転容量Wを、(G-ΣWC)よりも大きく且つ(G-ΣWC)に最も近い運転容量に調整する。
 これにより、優先順位の高いすべての第2レシプロ圧縮機14の運転容量Wを確保した上で、N台目の第2レシプロ圧縮機14の運転容量Wを、ゼロより大きい最小容量以上に設定することができる。
 例えば図8において、上から3番目の1台は、優先順位が3番であり、W>G-ΣWA-ΣWB=G-W4-W3を満たすWはW1よりも少ない。この場合、運転容量WをW1に調整する。
In step S18, the second capacity adjustment unit 34b adjusts the Nth operation capacity W to a value larger than the remaining capacity obtained by subtracting ΣWC from the total gas flow rate G. For example, the second capacity adjustment unit 34b adjusts the Nth operation capacity W to an operation capacity that is larger than (G-ΣWC) and closest to (G-ΣWC).
As a result, the operating capacity W of all the second reciprocating compressors 14 having high priority is secured, and the operating capacity W of the Nth second reciprocating compressor 14 is set to be equal to or greater than the minimum capacity greater than zero. be able to.
For example, in FIG. 8, the third unit from the top has the third priority, and W satisfying W> G−ΣWA−ΣWB = G−W4−W3 is smaller than W1. In this case, the operating capacity W is adjusted to W1.
 上述した実施形態の装置と方法によれば、複数の第1レシプロ圧縮機12により、貯蔵タンク2で発生するBOGを第1圧P1まで圧縮し、複数の第2レシプロ圧縮機14により、第1圧P1のBOGを第2圧P2まで圧縮することができる。
 従って、レシプロ圧縮機を用いて、貯蔵タンク2で発生するBOGを高圧(例えば4~6MPa)まで圧縮することができる。
According to the apparatus and method of the above-described embodiment, the BOG generated in the storage tank 2 is compressed to the first pressure P1 by the plurality of first reciprocating compressors 12, and the first reciprocating compressor 14 is used to compress the first BOG. The BOG at the pressure P1 can be compressed to the second pressure P2.
Therefore, the BOG generated in the storage tank 2 can be compressed to a high pressure (for example, 4 to 6 MPa) using a reciprocating compressor.
 また、中間配管16に流入し得る複数箇所からのBOGの定格最大流量に基づき、台数制御装置20aにより、複数の第2レシプロ圧縮機14の運転台数を制御するので、中間配管16内に圧力変動が生じる前に早期に第2レシプロ圧縮機14の起動又は停止ができる。
 従って、第2レシプロ圧縮機14の運転台数制御の追従性が高まるので、ガス流量のアンバランスを抑制し、配管内圧力の急変を防止することができる。
Further, since the number of operating units of the plurality of second reciprocating compressors 14 is controlled by the number control device 20a based on the rated maximum flow rate of BOG from a plurality of places that can flow into the intermediate pipe 16, the pressure fluctuations in the intermediate pipe 16 Before this occurs, the second reciprocating compressor 14 can be started or stopped early.
Accordingly, the followability of the control of the number of operating units of the second reciprocating compressor 14 is enhanced, so that an imbalance in the gas flow rate can be suppressed and a sudden change in the pressure in the pipe can be prevented.
 また、複数箇所から中間配管16に実際に流入する総ガス流量Gに基づき、容量調整装置20bにより、運転中の各第2レシプロ圧縮機14の運転容量Wを調整するので、中間配管16内に圧力変動が生じる前に早期に運転容量Wの調整ができる。
 従って、各第2レシプロ圧縮機14の容量調整の追従性が高まるので、ガス流量のアンバランスを抑制し、配管内圧力の急変を防止することができる。
Further, since the operation capacity W of each second reciprocating compressor 14 in operation is adjusted by the capacity adjustment device 20b based on the total gas flow rate G actually flowing into the intermediate pipe 16 from a plurality of locations, The operating capacity W can be adjusted early before the pressure fluctuation occurs.
Accordingly, the followability of the capacity adjustment of each second reciprocating compressor 14 is enhanced, so that an imbalance in the gas flow rate can be suppressed and a sudden change in the pipe internal pressure can be prevented.
 上述の実施形態によるBOG圧縮設備は、以下の付記1~8のように記載されてよい。 The BOG compression facility according to the above-described embodiment may be described as in the following supplementary notes 1 to 8.
(付記1)
 BOG圧縮設備は、
 貯蔵タンクで発生するBOGを第1圧まで圧縮する複数の第1レシプロ圧縮機と、
 前記第1圧のBOGを第2圧まで圧縮する複数の第2レシプロ圧縮機と、
 前記第1レシプロ圧縮機の吐出側と前記第2レシプロ圧縮機の吸入側とを連通する中間配管と、
 複数箇所から前記中間配管に流入し得るBOGの定格最大流量をそれぞれ検出する定格最大流量検出器と、
 前記複数箇所からの前記定格最大流量に基づき、前記第2レシプロ圧縮機の運転台数を制御する台数制御装置と、を備える。
(Appendix 1)
BOG compression equipment
A plurality of first reciprocating compressors that compress BOG generated in the storage tank to a first pressure;
A plurality of second reciprocating compressors that compress the first pressure BOG to a second pressure;
An intermediate pipe communicating the discharge side of the first reciprocating compressor and the suction side of the second reciprocating compressor;
A rated maximum flow rate detector that detects the rated maximum flow rate of the BOG that can flow into the intermediate pipe from a plurality of locations;
A number control device for controlling the number of operating second reciprocating compressors based on the maximum rated flow rate from the plurality of locations.
(付記2)
 上記付記1において、前記台数制御装置は、
 それぞれの前記定格最大流量から最大総ガス流量を予測する最大総ガス流量予測部と、
 前記最大総ガス流量に基づいて前記第2レシプロ圧縮機の指令台数を計算する指令台数計算部と、
 前記第2レシプロ圧縮機の現在の運転台数と前記指令台数とを比較し、前記現在の運転台数が前記指令台数と一致するように運転台数の増加又は減少を指令する指令出力部と、を有する。
(Appendix 2)
In the above supplementary note 1, the number control device is:
A maximum total gas flow prediction unit for predicting a maximum total gas flow from each of the rated maximum flows;
A command number calculator for calculating a command number of the second reciprocating compressor based on the maximum total gas flow rate;
A command output unit that compares the current operating number of the second reciprocating compressor with the commanded number and commands an increase or decrease in the operating number so that the current operating number matches the commanded number; .
(付記3)
 上記付記2において、前記指令台数計算部は、前記最大総ガス流量と各前記第2レシプロ圧縮機の定格最大流量とから、前記指令台数を計算し、
 前記指令出力部は、前記指令台数が現在の運転台数を超える場合に運転台数を増やす増台指令を出力し、現在の運転台数より1台少ない台数が前記指令台数を超える場合に運転台数を減らす減台指令を出力する。
(Appendix 3)
In Supplementary Note 2, the command number calculation unit calculates the command number from the maximum total gas flow rate and the rated maximum flow rate of each of the second reciprocating compressors,
The command output unit outputs a command to increase the number of operating units when the commanded number exceeds the current operating number, and reduces the number of operating units when the number less than the current operating number exceeds the commanded number Output reduction command.
(付記4)
 上記付記1において、上述のBOG圧縮設備は、前記第2レシプロ圧縮機をバイパスしてその吐出側と前記中間配管を連通するリサイクルラインと、
 該リサイクルラインに設けられ、前記第2レシプロ圧縮機の前記吐出側から前記中間配管に戻るガス流量を制御する戻しガス流量制御弁と、を備える。
(Appendix 4)
In the above supplementary note 1, the BOG compression facility described above includes a recycle line that bypasses the second reciprocating compressor and communicates the discharge side with the intermediate pipe.
A return gas flow rate control valve that is provided in the recycle line and controls a gas flow rate that returns from the discharge side of the second reciprocating compressor to the intermediate pipe.
(付記5)
 上記付記1~4のいずれかにおいて、各前記第2レシプロ圧縮機の運転容量は、互いに異なる2以上の運転容量にステップ状に調整可能であり、
 前記複数箇所から前記中間配管に実際に流入する総ガス流量を検出する総ガス流量検出器と、
 前記運転台数の制御で運転中となっている各前記第2レシプロ圧縮機の運転容量を、前記総ガス流量に基づいて調整する容量調整装置と、を備える。
(Appendix 5)
In any one of Appendices 1 to 4, the operating capacity of each of the second reciprocating compressors can be adjusted stepwise to two or more different operating capacities,
A total gas flow detector for detecting the total gas flow actually flowing into the intermediate pipe from the plurality of locations;
A capacity adjusting device that adjusts the operating capacity of each of the second reciprocating compressors that are operating under the control of the number of operating units based on the total gas flow rate.
(付記6)
 上記付記5において、前記容量調整装置は、
 (1)前記中間配管を流れる前記総ガス流量が、運転中である各前記第2レシプロ圧縮機の運転容量の総和を超えたら、運転中である前記複数の第2レシプロ圧縮機の少なくともいずれかの運転容量を、最大運転容量側へ切り替え、または
 (2)前記総ガス流量Gが、運転中の各前記第2レシプロ圧縮機の運転容量の総和Wsよりも小さく、かつ、前記総和Wsから前記総ガス流量Gを引いた値(Ws-G)が、前記第2レシプロ圧縮機の運転容量の切り替え可能量よりも大きい場合に、運転中の各前記第2レシプロ圧縮機の運転容量をゼロより大きい値に維持しつつ、運転中である前記複数の第2レシプロ圧縮機の少なくともいずれかの運転容量を最小運転容量側へ切り替える。
(Appendix 6)
In Appendix 5, the capacity adjusting device is
(1) At least one of the plurality of second reciprocating compressors in operation when the total gas flow rate flowing through the intermediate pipe exceeds the total operating capacity of the second reciprocating compressors in operation. Or (2) the total gas flow rate G is smaller than the total operating capacity Ws of the second reciprocating compressors in operation, and the total Ws When the value (Ws−G) obtained by subtracting the total gas flow rate G is larger than the switchable amount of the operation capacity of the second reciprocating compressor, the operation capacity of each of the second reciprocating compressors in operation is less than zero. While maintaining the large value, the operating capacity of at least one of the plurality of second reciprocating compressors in operation is switched to the minimum operating capacity side.
(付記7)
 上記付記5において、運転中の前記第2レシプロ圧縮機が2台以上であり、運転中の前記複数の第2レシプロ圧縮機にそれぞれ優先順位が設定されている場合に、
 (A)運転中の前記第2レシプロ圧縮機の運転容量の総和が、前記中間配管に流入する前記総ガス流量を超え、
 (B)前記優先順位が高い前記第2レシプロ圧縮機ほど高い運転容量を有し、かつ、
 (C)運転中のすべての前記第2レシプロ圧縮機の運転容量がゼロより大きくなるように、
 前記容量調整装置は、各前記第2レシプロ圧縮機の運転容量を調整する。
(Appendix 7)
In Appendix 5, when there are two or more second reciprocating compressors in operation and priority is set for each of the plurality of second reciprocating compressors in operation,
(A) The total operating capacity of the second reciprocating compressor in operation exceeds the total gas flow rate flowing into the intermediate pipe,
(B) the second reciprocating compressor having a higher priority has a higher operating capacity, and
(C) The operating capacity of all the second reciprocating compressors in operation is greater than zero.
The capacity adjusting device adjusts an operating capacity of each of the second reciprocating compressors.
(付記8)
 上記付記5において、前記容量調整装置は、運転中の前記第2レシプロ圧縮機がN台(N≧2)であり、運転中の前記複数の第2レシプロ圧縮機にそれぞれ優先順位が設定されている場合に、
 優先順位の順に、1台目からK台目(1≦K≦N-1)までの運転容量を、前記総ガス流量から、1台目から(K-1)台目までの運転容量の和と、(K+1)台目からN台目までの、ゼロより大きい最低容量の和とを減算した残容量に基づいて調整する第1容量調整部と、
 優先順位がN番目の運転容量を、前記総ガス流量から、1台目から(N-1)台目までの運転容量の和を減算した残容量よりも大きい値に調整する第2容量調整部と、を有する。
(Appendix 8)
In Supplementary Note 5, the capacity adjusting device has N second reciprocating compressors in operation (N ≧ 2), and each of the plurality of second reciprocating compressors in operation is assigned a priority. If
In order of priority, the operating capacity from the first to the Kth (1 ≦ K ≦ N−1) is the sum of the operating capacity from the total gas flow to the first to the (K−1) th. And a first capacity adjustment unit that adjusts based on the remaining capacity obtained by subtracting the sum of the minimum capacity greater than zero from the (K + 1) th to the Nth,
A second capacity adjustment unit that adjusts the N-th priority operation capacity to a value larger than the remaining capacity obtained by subtracting the sum of the operation capacity from the first to the (N−1) th unit from the total gas flow rate. And having.
 上述の実施形態による、レシプロ圧縮機の台数制御方法は、以下の付記9、10のように記載されてよい。 The method for controlling the number of reciprocating compressors according to the above-described embodiment may be described as the following supplementary notes 9 and 10.
(付記9)
 レシプロ圧縮機の台数制御方法では、
 上記付記1のBOG圧縮設備を準備し、
 前記定格最大流量検出器により、前記複数箇所から前記中間配管に流入し得るBOGの定格最大流量をそれぞれ検出し、
 前記台数制御装置により、前記複数箇所からの前記定格最大流量に基づき、前記第2レシプロ圧縮機の運転台数を制御する。
(Appendix 9)
In the reciprocating compressor unit control method,
Prepare the BOG compression facility in Appendix 1 above,
The rated maximum flow rate detector detects the rated maximum flow rate of BOG that can flow into the intermediate pipe from the plurality of locations,
The number control device controls the number of operating second reciprocating compressors based on the rated maximum flow rate from the plurality of locations.
(付記10)
 上記付記10において、総ガス流量検出器により、前記複数箇所から前記中間配管に実際に流入する総ガス流量を検出し、
 前記複数の第2レシプロ圧縮機により、前記第1圧のBOGを第2圧まで圧縮し、
 前記運転台数の制御で運転中となっている各前記第2レシプロ圧縮機の運転容量を、容量調整装置により、前記総ガス流量に基づいて、2以上のステップ状に調整する。
(Appendix 10)
In the above supplementary note 10, the total gas flow rate detector detects the total gas flow rate actually flowing into the intermediate pipe from the plurality of locations,
The plurality of second reciprocating compressors compress the first pressure BOG to a second pressure,
The operating capacity of each of the second reciprocating compressors that are operating under the control of the number of operating units is adjusted in two or more steps by a capacity adjusting device based on the total gas flow rate.
 なお、本開示は上述した実施形態に限定されず、特許請求の範囲の記載によって示され、さらに特許請求の範囲の記載と均等の意味および範囲内でのすべての変更を含むものである。 It should be noted that the present disclosure is not limited to the above-described embodiment, is shown by the description of the scope of claims, and further includes all modifications within the meaning and scope equivalent to the description of the scope of claims.
C シリンダ
D ピストン
Gmax 最大総ガス流量
G1、G2、G3 定格最大流量
g 処理可能流量
M 駆動源(モータ)
P0 第0圧(低圧)
P1 第1圧(中圧)
P2 第2圧(高圧)
V アンロード弁
W 運転容量
W1 第1容量
W2 第2容量
W3 第3容量
W4 第4容量
1 低温液化ガス
2 貯蔵タンク
3 供給ライン
4 ポンプ
5 蒸発器
6 ガス移送ライン
7 合流管
8 需要先(発電所)
9 プロセス
10 第1制御装置
11 第1圧力検出器
12 第1レシプロ圧縮機
13 総ガス流量検出器
14 第2レシプロ圧縮機
15 BOG払出しライン
16 中間配管
17 高圧ガスライン
18 定格最大流量検出器
19 第2圧力検出器
20 第2制御装置
20a 台数制御装置
20b 容量調整装置
21 リサイクルライン
22 戻しガス流量制御弁
23 記憶装置
24 演算装置
24a 最大総ガス流量予測部
24b 指令台数計算部
24c 指令出力部
25 出力装置
33 記憶装置
34 演算装置
34a 第1容量調整部
34b 第2容量調整部
35 出力装置
C Cylinder D Piston Gmax Maximum total gas flow rate G1, G2, G3 Rated maximum flow rate g Processable flow rate M Drive source (motor)
P0 0th pressure (low pressure)
P1 First pressure (medium pressure)
P2 Second pressure (high pressure)
V Unloading valve W Operating capacity W1 1st capacity W2 2nd capacity W3 3rd capacity W4 4th capacity 1 Low temperature liquefied gas 2 Storage tank 3 Supply line 4 Pump 5 Evaporator 6 Gas transfer line 7 Merge pipe 8 Demand destination (power generation Place)
9 Process 10 First control device 11 First pressure detector 12 First reciprocating compressor 13 Total gas flow detector 14 Second reciprocating compressor 15 BOG discharge line 16 Intermediate piping 17 High-pressure gas line 18 Rated maximum flow detector 19 2 Pressure detector 20 Second control device 20a Number control device 20b Capacity adjustment device 21 Recycle line 22 Return gas flow rate control valve 23 Storage device 24 Arithmetic device 24a Maximum total gas flow rate prediction unit 24b Command number calculation unit 24c Command output unit 25 Output Device 33 Storage device 34 Computing device 34a First capacity adjustment unit 34b Second capacity adjustment unit 35 Output device

Claims (10)

  1.  貯蔵タンクで発生するBOGを第1圧まで圧縮する複数の第1レシプロ圧縮機と、
     前記第1圧のBOGを第2圧まで圧縮する複数の第2レシプロ圧縮機と、
     前記第1レシプロ圧縮機の吐出側と前記第2レシプロ圧縮機の吸入側とを連通する中間配管と、
     複数箇所から前記中間配管に流入し得るBOGの定格最大流量をそれぞれ検出する定格最大流量検出器と、
     前記複数箇所からの前記定格最大流量に基づき、前記第2レシプロ圧縮機の運転台数を制御する台数制御装置と、を備えるBOG圧縮設備。
    A plurality of first reciprocating compressors that compress BOG generated in the storage tank to a first pressure;
    A plurality of second reciprocating compressors that compress the first pressure BOG to a second pressure;
    An intermediate pipe communicating the discharge side of the first reciprocating compressor and the suction side of the second reciprocating compressor;
    A rated maximum flow rate detector that detects the rated maximum flow rate of the BOG that can flow into the intermediate pipe from a plurality of locations;
    A BOG compression facility comprising: a number control device that controls the number of operating second reciprocating compressors based on the rated maximum flow rate from the plurality of locations.
  2.  前記台数制御装置は、
     それぞれの前記定格最大流量から最大総ガス流量を予測する最大総ガス流量予測部と、
     前記最大総ガス流量に基づいて前記第2レシプロ圧縮機の指令台数を計算する指令台数計算部と、
     前記第2レシプロ圧縮機の現在の運転台数と前記指令台数とを比較し、前記現在の運転台数が前記指令台数と一致するように運転台数の増加又は減少を指令する指令出力部と、を有する、請求項1に記載のBOG圧縮設備。
    The number controller is
    A maximum total gas flow prediction unit for predicting a maximum total gas flow from each of the rated maximum flows;
    A command number calculator for calculating a command number of the second reciprocating compressor based on the maximum total gas flow rate;
    A command output unit that compares the current operating number of the second reciprocating compressor with the commanded number and commands an increase or decrease in the operating number so that the current operating number matches the commanded number; The BOG compression facility according to claim 1.
  3.  前記指令台数計算部は、前記最大総ガス流量と各前記第2レシプロ圧縮機の定格最大流量とから、前記指令台数を計算し、
     前記指令出力部は、前記指令台数が現在の運転台数を超える場合に運転台数を増やす増台指令を出力し、現在の運転台数より1台少ない台数が前記指令台数を超える場合に運転台数を減らす減台指令を出力する、請求項2に記載のBOG圧縮設備。
    The command number calculation unit calculates the command number from the maximum total gas flow rate and the rated maximum flow rate of each second reciprocating compressor,
    The command output unit outputs a command to increase the number of operating units when the commanded number exceeds the current operating number, and reduces the number of operating units when the number less than the current operating number exceeds the commanded number The BOG compression facility according to claim 2, which outputs a reduction command.
  4.  前記第2レシプロ圧縮機をバイパスしてその吐出側と前記中間配管を連通するリサイクルラインと、
     該リサイクルラインに設けられ、前記第2レシプロ圧縮機の前記吐出側から前記中間配管に戻るガス流量を制御する戻しガス流量制御弁と、を備える、請求項1に記載のBOG圧縮設備。
    A recycle line that bypasses the second reciprocating compressor and communicates the discharge side with the intermediate pipe;
    2. The BOG compression facility according to claim 1, further comprising: a return gas flow rate control valve that is provided in the recycle line and controls a gas flow rate returning from the discharge side of the second reciprocating compressor to the intermediate pipe.
  5.  各前記第2レシプロ圧縮機の運転容量は、互いに異なる2以上の運転容量にステップ状に調整可能であり、
     前記複数箇所から前記中間配管に実際に流入する総ガス流量を検出する総ガス流量検出器と、
     前記運転台数の制御で運転中となっている各前記第2レシプロ圧縮機の運転容量を、前記総ガス流量に基づいて調整する容量調整装置と、を備える、請求項1~4のいずれか一項に記載のBOG圧縮設備。
    The operating capacity of each of the second reciprocating compressors can be adjusted stepwise to two or more different operating capacities,
    A total gas flow detector for detecting the total gas flow actually flowing into the intermediate pipe from the plurality of locations;
    5. A capacity adjusting device that adjusts the operating capacity of each of the second reciprocating compressors that are operating under the control of the number of operating units based on the total gas flow rate. The BOG compression equipment as described in the item.
  6.  前記容量調整装置は、
     (1)前記中間配管を流れる前記総ガス流量が、運転中である各前記第2レシプロ圧縮機の運転容量の総和を超えたら、運転中である前記複数の第2レシプロ圧縮機の少なくともいずれかの運転容量を、最大運転容量側へ切り替え、または
     (2)前記総ガス流量Gが、運転中の各前記第2レシプロ圧縮機の運転容量の総和Wsよりも小さく、かつ、前記総和Wsから前記総ガス流量Gを引いた値(Ws-G)が、前記第2レシプロ圧縮機の運転容量の切り替え可能量よりも大きい場合に、運転中の各前記第2レシプロ圧縮機の運転容量をゼロより大きい値に維持しつつ、運転中である前記複数の第2レシプロ圧縮機の少なくともいずれかの運転容量を最小運転容量側へ切り替える、請求項5に記載のBOG圧縮設備。
    The capacity adjusting device is
    (1) At least one of the plurality of second reciprocating compressors in operation when the total gas flow rate flowing through the intermediate pipe exceeds the total operating capacity of the second reciprocating compressors in operation. Or (2) the total gas flow rate G is smaller than the total operating capacity Ws of the second reciprocating compressors in operation, and the total Ws When the value (Ws−G) obtained by subtracting the total gas flow rate G is larger than the switchable amount of the operation capacity of the second reciprocating compressor, the operation capacity of each of the second reciprocating compressors in operation is less than zero. The BOG compression facility according to claim 5, wherein the operating capacity of at least one of the plurality of second reciprocating compressors in operation is switched to the minimum operating capacity side while maintaining a large value.
  7.  運転中の前記第2レシプロ圧縮機が2台以上であり、運転中の前記複数の第2レシプロ圧縮機にそれぞれ優先順位が設定されている場合に、
     (A)運転中の前記第2レシプロ圧縮機の運転容量の総和が、前記中間配管に流入する前記総ガス流量を超え、
     (B)前記優先順位が高い前記第2レシプロ圧縮機ほど高い運転容量を有し、かつ、
     (C)運転中のすべての前記第2レシプロ圧縮機の運転容量がゼロより大きくなるように、
     前記容量調整装置は、各前記第2レシプロ圧縮機の運転容量を調整する、請求項5に記載のBOG圧縮設備。
    When there are two or more second reciprocating compressors in operation and priority is set for each of the plurality of second reciprocating compressors in operation,
    (A) The total operating capacity of the second reciprocating compressor in operation exceeds the total gas flow rate flowing into the intermediate pipe,
    (B) the second reciprocating compressor having a higher priority has a higher operating capacity, and
    (C) The operating capacity of all the second reciprocating compressors in operation is greater than zero.
    The BOG compression facility according to claim 5, wherein the capacity adjusting device adjusts an operating capacity of each of the second reciprocating compressors.
  8.  前記容量調整装置は、運転中の前記第2レシプロ圧縮機がN台(N≧2)であり、運転中の前記複数の第2レシプロ圧縮機にそれぞれ優先順位が設定されている場合に、
     優先順位の順に、1台目からK台目(1≦K≦N-1)までの運転容量を、前記総ガス流量から、1台目から(K-1)台目までの運転容量の和と、(K+1)台目からN台目までの、ゼロより大きい最低容量の和とを減算した残容量に基づいて調整する第1容量調整部と、
     優先順位がN番目の運転容量を、前記総ガス流量から、1台目から(N-1)台目までの運転容量の和を減算した残容量よりも大きい値に調整する第2容量調整部と、を有する、請求項5に記載のBOG圧縮設備。
    In the capacity adjustment device, when the second reciprocating compressor in operation is N units (N ≧ 2), and priority is set for each of the plurality of second reciprocating compressors in operation,
    In order of priority, the operating capacity from the first to the Kth (1 ≦ K ≦ N−1) is the sum of the operating capacity from the total gas flow to the first to the (K−1) th. And a first capacity adjustment unit that adjusts based on the remaining capacity obtained by subtracting the sum of the minimum capacity greater than zero from the (K + 1) th to the Nth,
    A second capacity adjustment unit that adjusts the N-th priority operation capacity to a value larger than the remaining capacity obtained by subtracting the sum of the operation capacity from the first to the (N−1) th unit from the total gas flow rate. The BOG compression facility according to claim 5, comprising:
  9.  請求項1に記載のBOG圧縮設備を準備し、
     前記定格最大流量検出器により、前記複数箇所から前記中間配管に流入し得るBOGの定格最大流量をそれぞれ検出し、
     前記台数制御装置により、前記複数箇所からの前記定格最大流量に基づき、前記第2レシプロ圧縮機の運転台数を制御する、レシプロ圧縮機の制御方法。
    Preparing the BOG compression facility according to claim 1;
    The rated maximum flow rate detector detects the rated maximum flow rate of BOG that can flow into the intermediate pipe from the plurality of locations,
    A control method for a reciprocating compressor, wherein the number control device controls the number of operating second reciprocating compressors based on the rated maximum flow rate from the plurality of locations.
  10.  総ガス流量検出器により、前記複数箇所から前記中間配管に実際に流入する総ガス流量を検出し、
     前記複数の第2レシプロ圧縮機により、前記第1圧のBOGを第2圧まで圧縮し、
     前記運転台数の制御で運転中となっている各前記第2レシプロ圧縮機の運転容量を、容量調整装置により、前記総ガス流量に基づいて、2以上のステップ状に調整する、請求項9に記載のレシプロ圧縮機の制御方法。
     
     
    The total gas flow detector detects the total gas flow actually flowing into the intermediate pipe from the plurality of locations,
    The plurality of second reciprocating compressors compress the first pressure BOG to a second pressure,
    The operation capacity of each of the second reciprocating compressors that are operating under the control of the number of operating units is adjusted in two or more steps by a capacity adjustment device based on the total gas flow rate. The control method of the reciprocating compressor as described.

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