Compressor system and plant

Abstract

This compressor system has: a supply line that supplies a gas compressed by a compressor to a load; a first recycle line that is branched and connected to the supply line between the compressor and the load and that is merged and connected to the supply line on the upstream side from the compressor; a second recycle line that is branched and connected to the supply line between the compressor and the load and that is merged and connected to the supply line on the upstream side from the compressor and the upstream side from a position where the first recycle line is merged and connected; a first control valve that is provided to the first recycle line; a second control valve that is provided to the second recycle line; and a third control valve that is provided to the supply line between a position where the second recycle line is merged and connected and the position where the first recycle line is merged and connected.

Description

Compressor systems and plants

[0001] This application claims priority to Japanese Patent Application No. 2024-012567, filed on January 31, 2024, the contents of which are incorporated herein by reference.

[0002] When a compressor is operated with repeated start-up and shutdown, stress changes (stress cycles) occur in the various rotating components that make up the compressor, affecting their lifespan and leading to increased maintenance costs. For this reason, in plants equipped with compressors, it is desirable to operate the compressor at a constant rotation speed as much as possible. However, there are cases where the compressor rotation speed must be changed in response to demands from the load that uses the gas compressed by the compressor.

[0003] In response to this, Patent Document 1 discloses a configuration including a compression line equipped with a compressor that compresses gas, and a recycle line that bypasses the compressor and returns gas that has passed through the compressor to the upstream side of the compressor. In this configuration, when the gas flow rate required by the load side is less than 100%, a portion of the gas discharged from the compressor at 100% flow rate is returned to the upstream side of the compressor through the recycle line. This allows the compressor to maintain operation at a constant rotation speed while supplying gas to the load side at a flow rate that corresponds to the load side's request.

[0004] Special Publication No. 2012-504723

[0005] However, in the configuration described in Patent Document 1, even if the load side requests a flow rate less than 100%, the compressor is operated at a rotation speed that allows it to discharge 100% of the flow rate, making it difficult to reduce the energy consumption associated with driving the compressor.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a compressor system and a plant that can reduce maintenance costs and energy consumption associated with driving the compressor.

[0007] In order to solve the above-mentioned problems, a compressor system according to the present disclosure is a compressor system that compresses gas supplied from a tank and supplies the compressed gas to a load. The compressor system includes a compression system. The compression system includes a supply line, a first recycle line, a second recycle line, a first control valve, a second control valve, and a third control valve. The supply line includes a compressor that compresses the gas supplied from the tank. The supply line supplies the gas compressed by the compressor to the load. The first recycle line is branched off from the supply line between the compressor and the load and is connected to merge with the supply line upstream of the compressor. The second recycle line is branched off from the supply line between the compressor and the load and is connected to merge with the supply line upstream of the compressor and upstream of the position where the first recycle line merges. The first control valve is provided midway along the first recycle line. The second control valve is provided midway along the second recycle line. The third control valve is provided in the supply line between a position where the supply line is joined to the second recycle line and a position where the supply line is joined to the first recycle line.

[0008] A plant according to the present disclosure includes the compressor system described above, the tank, and the load.

[0009] The compressor system and plant disclosed herein can reduce maintenance costs and energy consumption associated with driving the compressor.

[0010] FIG. 1 is a diagram showing a schematic configuration of a plant including a compressor system according to a first embodiment of the present disclosure. FIG. 1 is a diagram showing the open / close states of a first control valve, a second control valve, and a third control valve, and the state of gas flow, when the flow rate of gas supplied from the compression system to the load is 100% in the compressor system according to the first embodiment of the present disclosure. FIG. 1 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve, and the state of gas flow, when the flow rate of gas supplied from the compression system to the load is changed from 100% to 50% in the compressor system according to the first embodiment of the present disclosure. FIG. 1 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve, and the state of gas flow, when the flow rate of gas supplied from the compression system to the load is changed from a state greater than 0% to 0% in the compressor system according to the first embodiment of the present disclosure. FIG. 1 is a diagram showing a schematic configuration of a plant including a compressor system according to a second embodiment of the present disclosure. FIG. 1 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve, and the state of gas flow, when the flow rate of gas supplied from the compression system to the load is 100% in the compressor system according to the second embodiment of the present disclosure. 1 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve, and the gas flow state when the flow rate of gas supplied from the compression system to the load is changed from 100% to 50% in the compressor system according to the second embodiment of the present disclosure. 2 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve, and the gas flow state when the flow rate of gas supplied from the compression system to the load is changed from 100% to less than 50% in the compressor system according to the second embodiment of the present disclosure. 3 is a diagram showing another example of the open / close states of the first control valve, the second control valve, and the third control valve of each compression system, and the gas flow state when the flow rate of gas supplied from the compression system to the load is changed from 100% to less than 50% in the compressor system according to the second embodiment of the present disclosure. 4 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve of each compression system, and the gas flow state when the flow rate of gas supplied from the compression system to the load is changed from a state greater than 0% to 0% in the compressor system according to the second embodiment of the present disclosure.FIG. 10 is a diagram illustrating a schematic configuration of a plant including a compressor system according to a modified example of an embodiment of the present disclosure.

[0011] First Embodiment A compressor system and a plant according to an embodiment of the present disclosure will be described below with reference to Figures 1 to 11. (Overall Configuration of Plant) As shown in Figure 1, a plant 1A according to this embodiment includes a tank 2, a load 3, a compressor system 5A, and a control unit 60.

[0012] The tank 2 stores gas to be compressed by the compressor system 5A. In this embodiment, the tank 2 stores hydrogen gas. The tank 2 is a tank of a water electrolysis device 2A that produces hydrogen gas from water (pure water).

[0013] The load 3 performs a predetermined process using the hydrogen gas compressed by the compressor system 5 A. In this embodiment, the load 3 is a process device 3P that produces ammonia using the hydrogen gas compressed by the compressor system 5 A.

[0014] (Configuration of Compressor System) The compressor system 5A compresses hydrogen gas, which is a gas supplied from the tank 2, and supplies the compressed gas to the load 3. The compressor system 5A includes a compression system 30. The compressor system 5A illustrated in this embodiment includes only one compression system 30. The compression system 30 is provided between an upstream line 101 to which hydrogen gas is supplied from the tank 2, and a downstream line 102 that supplies the hydrogen gas compressed by the compressor system 5A to the load 3. The compression system 30 includes a supply line 31, a first recycle line 32, a second recycle line 33, a first control valve 41, a second control valve 42, and a third control valve 43.

[0015] One end (upstream end) of the supply line 31 is connected to the upstream line 101. The other end (downstream end) of the supply line 31 is connected to the downstream line 102. Hydrogen gas supplied from the tank 2 and passed through the upstream line 101 flows from one end to the other end of the supply line 31. The supply line 31 is equipped with a compressor 34 that compresses the hydrogen gas supplied from the tank 2. In this embodiment, the supply line 31 is equipped with multiple compressors 34 connected in series, but the number of compressors 34 may be one. In addition, although the supply line 31 in this embodiment is equipped with three compressors 34, the number of compressors 34 can be appropriately set, for example, four or more compressors 34. The supply line 31 is equipped with a heat exchanger 35 downstream of each compressor 34. The heat exchanger 35 reduces the temperature of the hydrogen gas, which has been increased by being compressed by the compressor 34. The supply line 31 supplies the hydrogen gas compressed by the compressor 34 to the load 3.

[0016] The first recycle line 32 is connected to branch off from the supply line 31 at a position 201 between the compressor 34 and the load 3. The first recycle line 32 is connected to branch off from the supply line 31 between the load 3 and the most downstream compressor 34B of the multiple compressors 34. The first recycle line 32 is connected to merge with the supply line 31 at a position 202 upstream of the compressor 34. The first recycle line 32 is connected to merge with the supply line 31 upstream of the most upstream compressor 34A of the multiple compressors 34.

[0017] The first control valve 41 is provided midway along the first recycle line 32. The first control valve 41 is capable of opening and closing the flow path of hydrogen gas within the first recycle line 32. The first control valve 41 is configured so that its opening / closing and opening degree can be adjusted by a control unit 60, which will be described later.

[0018] The second recycle line 33 is connected to a branch line of the supply line 31 between the compressor 34 and the load 3. The second recycle line 33 is connected to a branch line of the supply line 31 at a position 201 between the compressor 34 and the load 3. The second recycle line 33 is connected to a junction of the supply line 31 at a position 203 upstream of the most upstream compressor 34A among the multiple compressors 34 and upstream of a position 202 where the first recycle line 32 is connected to a junction of the supply line 31.

[0019] The second control valve 42 is provided midway along the second recycle line 33. The second control valve 42 is capable of opening and closing the flow path of hydrogen gas within the second recycle line 33. The second control valve 42 is configured so that its opening and closing and its opening degree can be adjusted by a control unit 60, which will be described later.

[0020] The third control valve 43 is provided on the supply line 31 between a position 203 where the second recycle line 33 is joined and connected, and a position 202 where the first recycle line 32 is joined and connected.

[0021] In this embodiment, the compression system 30 may further include a check valve 45. The check valve 45 is provided in a portion of the supply line 31 that is closer to the load 3 than a position 201 where the first recycle line 32 and the second recycle line 33 are branched and connected. The check valve 45 prevents backflow of hydrogen gas from the load 3 side to the compressor 34, the first recycle line 32, and the second recycle line 33.

[0022] In this compression system 30, when the first control valve 41 is open, hydrogen gas compressed by the compressor 34 flows from position 201 into the first recycle line 32. The hydrogen gas that has flowed into the first recycle line 32 joins with the hydrogen gas in the supply line 31 at position 202 upstream of the compressor 34. In other words, the first recycle line 32 circulates (recycles) the hydrogen gas compressed by the compressor 34 to the supply line 31 upstream of the compressor 34.

[0023] When the second control valve 42 is open, hydrogen gas compressed by the compressor 34 flows into the second recycle line 33 from position 201. The hydrogen gas that has flowed into the second recycle line 33 merges with the hydrogen gas in the supply line 31 at position 203, which is upstream of the compressor 34 and upstream of position 202 where the first recycle line 32 is joined. In other words, the second recycle line 33 circulates (recycles) the hydrogen gas compressed by the compressor 34 to the supply line 31 upstream of the third control valve 43.

[0024] The control unit 60 controls the operation of the compressor system 5A. The control unit 60 controls the operation of the first control valve 41, the second control valve 42, and the third control valve 43. The control unit 60 controls the opening / closing operation and the opening degree of each of the first control valve 41, the second control valve 42, and the third control valve 43 in response to a load request from the load 3. The control unit 60 adjusts the flow rate of hydrogen gas supplied from the compression system 30 to the load 3 by controlling the opening / closing operation and the opening degree of each of the first control valve 41, the second control valve 42, and the third control valve 43. The flow rate (e.g., volumetric flow rate) of hydrogen gas supplied from the compression system 30 to the load 3 is expressed as a percentage of the hydrogen gas flow rate, such as 100%, 50%, or 0%, when a maximum supply flow rate of hydrogen gas preset in the compressor system 5A is 100%, for example.

[0025] Next, the flow of hydrogen gas according to the load of the plant 1A as described above will be described. FIG. 2 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve, and the gas flow state when the flow rate of gas supplied from the compression system to the load is 100%. As shown in FIG. 2, when the flow rate of hydrogen gas supplied from the compression system 30 to the load 3 is 100%, the control unit 60 closes the first control valve 41, closes the second control valve 42, and opens the third control valve 43. As a result, hydrogen gas supplied from the tank 2 via the upstream line 101 passes only through the supply line 31 and is sequentially compressed by the multiple compressors 34. The hydrogen gas compressed by the compressors 34 is supplied from the supply line 31 to the load 3 via the downstream line 102.

[0026] 3 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve, and the gas flow state when the flow rate of the gas supplied from the compression system to the load 3 is changed from 100% to 50%. When the flow rate of the hydrogen gas supplied from the compression system 30 to the load 3 is changed from greater than 0% to less than 100%, the control unit 60 closes the first control valve 41, opens the second control valve 42 to a degree corresponding to the request from the load 3, and opens the third control valve 43. More specifically, as shown in FIG. 3 , when the flow rate of the hydrogen gas supplied from the compression system 30 to the load 3 is changed from 100% to, for example, 50%, the control unit 60 closes the first control valve 41, opens the second control valve 42 (for example, fully open), and opens the third control valve 43. As a result, the hydrogen gas supplied from the tank 2 via the upstream line 101 passes through the supply line 31 and is sequentially compressed by the multiple compressors 34.

[0027] A portion of the hydrogen gas compressed by the compressor 34 flows from the supply line 31 into the second recycle line 33 at position 201. The hydrogen gas that has flowed into the second recycle line 33 joins with the hydrogen gas in the supply line 31 at position 203, upstream of the third control valve 43. As a result, the remainder of the hydrogen gas compressed by the compressor 34 is supplied from the supply line 31 to the downstream line 102 and to the load 3. At this time, the rotation speed of each compressor 34 remains constant, as in the state shown in FIG. 2 . In other words, the flow rate of hydrogen gas supplied to the load 3 is changed while the rotation speed of each compressor 34 is maintained constant. In this embodiment, the case where the second control valve 42 is fully opened to set the flow rate of hydrogen gas supplied to the load 3 to 50% has been exemplified. This is because the flow rate of hydrogen gas is preset to 50% when the second control valve 42 is fully open. In this embodiment, when the flow rate of hydrogen gas supplied to the load 3 is to be greater than 50% and less than 100%, for example, the third control valve 43 is opened, the first control valve 41 is closed, and the aperture of the first control valve 41 is adjusted to the closed side. Note that when the flow rate of hydrogen gas supplied to the load 3 is to be greater than 0% and equal to or less than 50%, the amount of recycled hydrogen may be adjusted by adjusting the aperture of the first control valve 41.

[0028] 4 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve, and the gas flow state when the flow rate of the gas supplied from the compression system to the load 3 is changed from a state greater than 0% to 0%. As shown in FIG. 4 , when the flow rate of hydrogen gas supplied from the compression system 30 to the load 3 is changed from a state greater than 0% to 0%, the control unit 60 opens the first control valve 41 and the second control valve 42 and closes the third control valve 43. As a result, the hydrogen gas supplied from the tank 2 via the upstream line 101 does not flow downstream of the third control valve 43 in the supply line 31. The hydrogen gas remaining downstream of the third control valve 43 in the supply line 31 flows from the supply line 31 into the second recycle line 33 at position 201. The hydrogen gas flowing into the second recycle line 33 merges with the hydrogen gas in the supply line 31 at position 203, upstream of the third control valve 43, and is returned to the tank 2 from the supply line 31 via the upstream line 101.

[0029] At this time, in the supply line 31, after the third control valve 43 is closed, the flow rate of hydrogen gas sucked into the compressor 34 decreases rapidly, which may result in a surge operation state. In such a case, because the first control valve 41 is open, some of the hydrogen gas remaining in the supply line 31 is returned to the supply line 31 upstream of the compressor 34 through the first recycle line 32. This prevents the compressor 34 from entering a surge operation state.

[0030] (Operation and Effect) In the compressor system 5A of the above embodiment, when the flow rate of hydrogen gas supplied from the compression system 30 to the load 3 is set to be greater than 0% and less than 100%, the control unit 60 closes the first control valve 41 and opens the second control valve 42 to a degree corresponding to the request from the load 3. As a result, a portion of the hydrogen gas compressed by the compressor 34 flows from the supply line 31 to the second recycle line 33, and the flow rate of hydrogen gas supplied from the compression system 30 to the load 3 can be adjusted in accordance with the request from the load 3. The hydrogen gas that flows into the second recycle line 33 then merges with the hydrogen gas in the supply line 31 upstream of the third control valve 43. The hydrogen gas that has merged with the hydrogen gas in the supply line 31 then passes through the third control valve 43 again and is compressed by the compressor 34. At this time, if the third control valve 43 lowers the suction pressure, the pressure loss in the third control valve 43 increases, and the inlet pressure and outlet pressure of the compressor 34 decrease. This allows the power required to drive the compressor 34 to be reduced while maintaining the rotation speed of the compressor 34.

[0031] Furthermore, in the above embodiment, when the flow rate of hydrogen gas supplied from the compression system 30 to the load 3 is reduced from a state greater than 0% to 0%, the control unit 60 opens the first control valve 41 and the second control valve 42 and closes the third control valve 43. As a result, the hydrogen gas in the supply line 31 is returned upstream through the second recycle line 33. In this manner, the hydrogen gas remaining in the compression system 30 can be returned to the upstream tank 2, etc. As a result, when the flow rate of hydrogen gas supplied from the compression system 30 to the load 3 is reduced to 0%, the flow rate of hydrogen gas circulating through the compressor 34 decreases, and the pressure and gas density of the circulating hydrogen gas decrease, thereby reducing the energy required to drive the compressor 34. Therefore, the compressor system 5A can be operated in various ways using the first recycle line 32 and the second recycle line 33, even while suppressing fluctuations in the rotation speed of the compressor 34. As a result, maintenance costs and energy consumption associated with driving the compressor 34 can be reduced.

[0032] Furthermore, in the plant 1A of the above embodiment, by being equipped with the compressor system 5A, maintenance costs and the amount of energy consumed by driving the compressor 34 can be reduced, thereby improving the marketability of the plant 1A.

[0033] In the above embodiment, the load 3 is a process device 3P that produces ammonia using hydrogen gas compressed by the compressor system 5A. Therefore, in the plant 1A that produces ammonia from hydrogen gas, it is possible to reduce the maintenance costs of the compressor system 5A that compresses the hydrogen gas and the energy consumption associated with driving the compressor 34.

[0034] In the above embodiment, the tank 2 stores the hydrogen gas generated from water in the water electrolysis apparatus 2A. This reduces the maintenance costs of the compressor system 5A that compresses the hydrogen gas generated from water in the water electrolysis apparatus 2A and the energy consumption associated with driving the compressor 34.

[0035] Second Embodiment Next, a second embodiment of a compressor system and a plant according to the present disclosure will be described. The second embodiment described below differs from the first embodiment only in the configuration in which the compressor system has multiple compression systems. Therefore, the same components as those in the first embodiment will be denoted by the same reference numerals and will not be described again. (Overall Configuration of Plant) As shown in FIG. 5, a plant 1B of this embodiment includes a tank 2, a load 3, a compressor system 5B, and a control unit 60.

[0036] (Configuration of Compressor System) The compressor system 5B compresses hydrogen gas as a gas supplied from the tank 2 and supplies the compressed gas to the load 3. In this embodiment, the compressor system 5B includes a plurality of compression systems 30 connected in parallel between the tank 2 and the load 3. The compressor system 5B in this embodiment includes, for example, two compression systems 30A and 30B. The number of compression systems 30 included in the compressor system 5B is not limited to two, and may be three or more. Each compression system 30 is provided in parallel between an upstream line 101 to which hydrogen gas is supplied from the tank 2 and a downstream line 102 that supplies the hydrogen gas compressed by the compressor system 5B to the load 3.

[0037] Each compression system 30 includes a supply line 31, a first recycle line 32, a second recycle line 33, a first control valve 41, a second control valve 42, a third control valve 43, and a check valve 45.

[0038] One end (upstream end) of the supply line 31 of each compression system 30 is connected to the upstream line 101. The supply lines 31 of the multiple compression systems 30 are branched off from the upstream line 101 at position 208 upstream of position 203. The other end (downstream end) of the supply line 31 of each compression system 30 is joined to the downstream line 102 at position 209 downstream of position 201.

[0039] Next, the gas flow according to the load of the plant 1B as described above will be described. FIG. 6 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve of each compression system, and the gas flow state when the flow rate of gas supplied from the compression system to the load is 100%. As shown in FIG. 6 , when the flow rate of hydrogen gas supplied from the multiple compression systems 30 to the load 3 is 100%, the control unit 60 closes the first control valve 41, closes the second control valve 42, and opens the third control valve 43 in each compression system 30. As a result, hydrogen gas supplied from the tank 2 via the upstream line 101 passes only through the supply line 31 of each compression system 30 and is sequentially compressed by the multiple compressors 34. The hydrogen gas compressed by the compressors 34 is supplied to the load 3 from the supply line 31 of each compression system 30 via the downstream line 102.

[0040] 7 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve of each compression system, and the flow state of hydrogen gas when the flow rate of hydrogen gas supplied from the compression system to the load is changed from 100% to 50%. When the number of compression systems 30 is N, and the flow rate of hydrogen gas required by the load 3 is greater than 0% and less than (100 / N)×(N−1)%, the control unit 60 controls the first control valve 41, the second control valve 42, and the third control valve 43 in the multiple compression systems 30 as follows:

[0041] 7 , when the flow rate of hydrogen gas required by the load 3 satisfies the above condition, the control unit 60 closes the third control valve 43 of at least one of the multiple compression systems 30, opens the third control valves 43 of the other compression systems 30, and sets the opening degree of at least one of the first control valve 41 and the second control valve 42 in accordance with the request of the load 3. Here, in this embodiment, the number N of the multiple compression systems is N=2. Therefore, when the flow rate of hydrogen gas required by the load 3 is greater than 0% and less than 50%, the control unit 60 closes the third control valve 43 of one of the two compression systems 30A, 30B, for example, the compression system 30A, and opens the first control valve 41 and the second control valve 42 to stop the supply of hydrogen gas to the load 3, while opening the third control valve 43 of the other compression system 30B and setting the opening degree of at least one of the first control valve 41 and the second control valve 42 in accordance with the request of the load 3 to continue the supply of hydrogen gas to the load 3.

[0042] As a result, in one compression system 30A, the hydrogen gas supplied from the tank 2 via the upstream line 101 no longer flows downstream of the third control valve 43 in the supply line 31, and is circulated via the first recycle line 32. Then, a portion of the hydrogen gas remaining downstream of the third control valve 43 in the supply line 31 flows from the supply line 31 into the second recycle line 33 at position 201. The hydrogen gas that has flowed into the second recycle line 33 joins with the hydrogen gas in the supply line 31 at position 203 upstream of the third control valve 43, and flows from the supply line 31 via the upstream line 101 into the other compression system 30B.

[0043] In the other compression system 30B, for example, when the flow rate of hydrogen gas supplied from the compression system 30B to the load 3 is set to 50%, the first control valve 41 and the second control valve 42 are fully closed. As a result, the hydrogen gas supplied from the tank 2 via the upstream line 101 passes only through the supply line 31 of the compression system 30B and is sequentially compressed by the multiple compressors 34. The hydrogen gas compressed by the compressors 34 is supplied to the load 3 from the supply line 31 of the compression system 30B via the downstream line 102.

[0044] 8 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve of each compression system and the gas flow state when the flow rate of gas supplied from the compression system to the load is changed from 100% to less than 50%. Furthermore, for example, when the flow rate of hydrogen gas supplied from compression system 30B to load 3 is set to 25% or more and less than 50%, at least one of the first control valve 41 and the second control valve 42 in the other compression system 30B is opened to a degree corresponding to the demand of load 3. For example, as shown in FIG. 8, when the first control valve 41 is opened to a degree corresponding to the demand of load 3 and the second control valve 42 is closed, hydrogen gas supplied from tank 2 to compression system 30B via upstream line 101 passes through supply line 31 of compression system 30B and is sequentially compressed by multiple compressors 34. A portion of the hydrogen gas compressed by compressor 34 flows from supply line 31 into first recycle line 32 of compression system 30B at position 201. The hydrogen gas that has flowed into the first recycle line 32 joins with the hydrogen gas in the supply line 31 at position 202. As a result, the remainder of the hydrogen gas compressed by the compressor 34 of the compression system 30B is supplied to the load 3 from the supply line 31 via the downstream line 102. In this way, the flow rate of the hydrogen gas supplied to the load 3 can be changed while maintaining the rotation speed of each compressor 34 constant.

[0045] 9 is a diagram showing another example of the open / close states of the first control valve, the second control valve, and the third control valve of each compression system and the gas flow state when the flow rate of the gas supplied from the compression system to the load is changed from 100% to less than 50%. Also, as shown in FIG. 9 , in another compression system 30B, for example, when the flow rate of hydrogen gas supplied from the compression system 30B to the load 3 is set to 25% or more and less than 50%, the first control valve 41 may be closed and the second control valve 42 may be opened to a degree corresponding to the demand of the load 3. In this case, hydrogen gas supplied from the tank 2 via the upstream line 101 to the compression system 30B passes through the supply line 31 of the compression system 30B and is sequentially compressed by the multiple compressors 34. A portion of the hydrogen gas compressed by the compressor 34 flows from the supply line 31 into the second recycle line 33 at position 201. As a result, the remainder of the hydrogen gas compressed by the compressor 34 is supplied from the supply line 31 to the load 3 via the downstream line 102.

[0046] Meanwhile, the hydrogen gas that has flowed into the second recycle line 33 joins with the hydrogen gas in the supply line 31 at position 203 upstream of the third control valve 43. The hydrogen gas that has joined with the hydrogen gas in the supply line 31 at position 203 is compressed again by the compressor 34. In this case, the third control valve 43 imparts a pressure loss to the hydrogen gas in the supply line 31, thereby reducing the inlet pressure and outlet pressure of the compressor 34. This allows the power required to drive the compressor 34 to be reduced even if the rotation speed of the compressor 34 remains constant.

[0047] 10 is a diagram showing the open / close states of the first control valve, the second control valve, and the third control valve of each compression system, and the gas flow state when the flow rate of gas supplied from the compression system to the load 3 is changed from a state greater than 0% to 0%. As shown in FIG. 10, when the flow rate of hydrogen gas supplied from the compression system 30 to the load 3 is changed from a state greater than 0% to 0%, the control unit 60 opens the first control valve 41 and the second control valve 42 and closes the third control valve 43 in all of the multiple compression systems 30.

[0048] As a result, in each of the compression systems 30, the hydrogen gas supplied from the tank 2 via the upstream line 101 no longer flows downstream of the third control valve 43 in the supply line 31. In the supply line 31 of each compression system 30, the hydrogen gas remaining downstream of the third control valve 43 flows from the supply line 31 into the second recycle line 33 at position 201. The hydrogen gas that has flowed into the second recycle line 33 of each compression system 30 merges with the hydrogen gas in the supply line 31 at position 203 upstream of the third control valve 43, and is returned from the supply line 31 via the upstream line 101 to the tank 2.

[0049] At this time, in the supply line 31 of each compression system 30, after the third control valve 43 is closed, the flow rate of hydrogen gas sucked into the compressor 34 decreases rapidly, which may result in a surge operation state. In such a case, because the first control valve 41 of each compression system 30 is open, some of the hydrogen gas remaining in the supply line 31 is returned to the supply line 31 upstream of the compressor 34 through the first recycle line 32. This makes it possible to prevent the compressor 34 from entering a surge operation state.

[0050] (Operation and Effect) In the compressor system 5B of the second embodiment, similarly to the first embodiment, the maintenance cost and the amount of energy consumption associated with driving the compressor 34 can be reduced.

[0051] Furthermore, in the second embodiment, a plurality of compression systems 30 are provided which are connected in parallel between the tank 2 and the load 3. This allows the hydrogen gas to be compressed by the plurality of compression systems 30 and supplied to the load 3. Depending on the requirements of the load 3, the hydrogen gas can be compressed by only some of the plurality of compression systems 30 and supplied to the load 3.

[0052] In the second embodiment, the supply line 31 is provided with a check valve 45. As a result, when hydrogen gas is compressed in only some of the compression systems 30 among the multiple compression systems 30 and supplied to the load 3, the hydrogen gas compressed in some of the compression systems 30 is prevented from flowing back into the other compression systems 30.

[0053] Furthermore, in the second embodiment, when the flow rate of hydrogen gas required by the load 3 is greater than 0% and less than (100 / N)×(N−1)%, the control unit 60 closes the third control valve 43 of at least one of the multiple compression systems 30. This causes hydrogen gas to flow into the other compression systems 30 whose third control valves 43 are open. In the other compression systems 30, by opening at least one of the first control valve 41 and the second control valve 42 to an opening degree in accordance with the request of the load 3, hydrogen gas can be supplied to the load 3 at a flow rate in accordance with the request.

[0054] Furthermore, in the second embodiment, when the flow rate of hydrogen gas required by the load 3 drops from a state greater than 0% to 0%, the control unit 60 closes all of the third control valves 43 of the multiple compression systems 30. As a result, in each of the multiple compression systems 30, the hydrogen gas in the supply line 31 passes through the second recycle line 33 and is returned to the upstream side. In this way, the hydrogen gas remaining in the multiple compression systems 30 can be returned to the upstream tank 2, etc.

[0055] Other Embodiments While the embodiments of the present disclosure have been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design modifications and the like are also included within the scope of the present disclosure. In the above embodiment, the tank 2 is a tank for storing hydrogen gas in a water electrolysis apparatus 2A that generates hydrogen gas from water, but the present disclosure is not limited thereto. For example, as shown in FIG. 11 , the tank 2 may be a tank for storing hydrogen gas produced by various hydrogen production processes 2P.

[0056] In the above embodiment, the load 3 generates ammonia using the hydrogen gas compressed by the compressor system 5A, but this is not limited to this. The load 3 may use the hydrogen gas compressed by the compressor system 5A for other purposes. Furthermore, the compressor system 5A may compress gases other than hydrogen gas.

[0057] In the above embodiment, the control unit 60 controls the operations of the first control valve 41, the second control valve 42, and the third control valve 43, but this is not limiting. The opening and closing and adjustment of the opening degrees of the first control valve 41, the second control valve 42, and the third control valve 43 can also be performed by an operator by remote control, manual operation, or the like.

[0058] <Additional Notes> The compressor systems 5A and 5B and the plants 1A and 1B described in the respective embodiments can be understood, for example, as follows.

[0059] (1) The compressor systems 5A and 5B according to a first aspect are compressor systems 5A and 5B that compress gas supplied from a tank 2 and supply the gas to a load 3, and include a compressor 34 that compresses the gas supplied from the tank 2, a supply line 31 that supplies the gas compressed by the compressor 34 to the load 3, a first recycle line 32 that is branched off and connected to the supply line 31 between the compressor 34 and the load 3 and that is joined and connected to the supply line 31 upstream of the compressor 34, and a second recycle line 32 that is branched off and connected to the supply line 31 between the compressor 34 and the load 3 and that is joined and connected to the supply line 31 upstream of the compressor 34. The compression system 30 includes a second recycle line 33 that is connected to the supply line 31 upstream of a compressor 34 and upstream of a position 202 where the first recycle line 32 is connected to the supply line 31, a first control valve 41 that is provided in the first recycle line 32, a second control valve 42 that is provided in the second recycle line 33, and a third control valve 43 that is provided in the supply line 31 between the position 203 where the second recycle line 33 is connected to the supply line 31 and the position 202 where the first recycle line 32 is connected to the supply line 31. An example of the gas is hydrogen gas.

[0060] In this compressor system 5A, 5B, when the second control valve 42 is closed, a portion of the gas compressed by the compressor 34 flows from the supply line 31 into the first recycle line 32. The gas that has flowed into the first recycle line 32 merges with the gas in the supply line 31 upstream of the compressor 34. This allows the flow rate of the gas supplied from the compression system 30 to the load 3 to be less than 100%. Furthermore, when the first control valve 41 is closed, a portion of the gas compressed by the compressor 34 flows from the supply line 31 into the second recycle line 33. The gas that has flowed into the second recycle line 33 merges with the gas in the supply line 31 upstream of the third control valve 43. Then, the gas that has merged with the gas in the supply line 31 upstream of the third control valve 43 passes through the third control valve 43 again and is compressed by the compressor 34. When the third control valve 43 is used to reduce the suction pressure, the pressure loss in the third control valve 43 increases, and the inlet pressure and outlet pressure of the compressor 34 decrease. This reduces the power required to drive the compressor 34, even if the compressor 34 rotation speed remains constant. Furthermore, when the third control valve 43 is closed, the gas in the supply line 31 is returned upstream through the second recycle line 33. In this way, the gas remaining in the compression system 30 can be returned to the upstream tank 2, etc. In this way, various operations can be performed using the first recycle line 32 and the second recycle line 33 while suppressing fluctuations in the compressor 34 rotation speed. As a result, maintenance costs and energy consumption associated with driving the compressor 34 can be reduced.

[0061] (2) A compressor system 5A according to a second aspect is the compressor system 5A of (1), and includes a control unit 60 that controls the operation of the first control valve 41, the second control valve 42, and the third control valve 43. When the flow rate of the gas supplied from the compression system 30 to the load 3 is set to be greater than 0% and less than 100%, the control unit 60 closes the first control valve 41 and opens the second control valve 42 to an opening degree according to the request from the load 3.

[0062] By adjusting the aperture of the second control valve 42 to a value corresponding to the demand of the load 3 in this manner, a portion of the gas compressed by the compressor 34 flows from the supply line 31 into the second recycle line 33, and the flow rate of the gas supplied from the compression system 30 to the load 3 can be adjusted according to the demand of the load 3. The gas that flows into the second recycle line 33 merges with the gas in the supply line 31 upstream of the third control valve 43. Then, the gas that has merged with the gas in the supply line 31 upstream of the third control valve 43 passes through the third control valve 43 again and is compressed by the compressor 34. When the suction pressure is reduced by the third control valve 43, the pressure loss in the third control valve 43 increases, and the inlet pressure and outlet pressure of the compressor 34 decrease.

[0063] (3) A compressor system 5A according to a third aspect is the compressor system 5A of (1) or (2), and includes a control unit 60 that controls the operation of the first control valve 41, the second control valve 42, and the third control valve 43. When the flow rate of the gas supplied from the compression system 30 to the load 3 is reduced from a state greater than 0% to 0%, the control unit 60 opens the first control valve 41 and the second control valve 42 and closes the third control valve 43.

[0064] As a result, the gas in the supply line 31 is returned to the upstream side through the second recycle line 33. In this way, the gas remaining in the compression system 30 can be returned to the upstream tank 2, etc. As a result, when the flow rate of the gas supplied from the compression system 30 to the load 3 is set to 0%, the flow rate of the gas circulating through the compressor 34 decreases, and the pressure and gas density of the circulating gas decrease, so that the energy required to drive the compressor 34 can be reduced.

[0065] (4) A compressor system 5B according to a fourth aspect is the compressor system 5B of (1), and includes a plurality of the compression systems 30 connected in parallel between the tank 2 and the load 3.

[0066] This allows the gas to be compressed by the multiple compression systems 30 and supplied to the load 3. Depending on the request of the load 3, the gas can also be compressed by only some of the multiple compression systems 30 and supplied to the load 3.

[0067] (5) The compressor system 5B according to the fifth aspect is the compressor system 5B of (4), and is provided with a check valve 45 in the supply line 31 closer to the load 3 than the position 201 where the first recycle line 32 branches off and the position 201 where the second recycle line 33 branches off, to prevent backflow of the gas from the load 3 side to the compressor 34, the first recycle line 32 and the second recycle line 33.

[0068] As a result, when gas is compressed in only some of the compression systems 30 out of the multiple compression systems 30 and supplied to the load 3, the gas compressed in some of the compression systems 30 is prevented from flowing back into the other compression systems 30.

[0069] (6) A compressor system 5B according to a sixth aspect is the compressor system 5B of (4) or (5), and includes a control unit 60 that controls the operation of the first control valve 41, the second control valve 42, and the third control valve 43. When the gas flow rate required by the load 3 is greater than 0% and less than (100 / N)×(N−1), where N is the number of the plurality of compression systems 30, the control unit 60 closes the third control valve 43 of at least one of the plurality of compression systems 30, opens the third control valve 43 of the other of the plurality of compression systems 30, and sets the opening degree of at least one of the first control valve 41 and the second control valve 42 in accordance with the request of the load 3.

[0070] As a result, the gas flows into the other compression system 30, which has the third control valve 43 open. In the other compression system 30, by opening at least one of the first control valve 41 and the second control valve 42 to an opening degree according to the demand of the load 3, the gas can be supplied to the load 3 at a flow rate according to the demand.

[0071] (7) A compressor system 5B according to a seventh aspect is the compressor system 5B of (6), in which the control unit 60 closes all of the third control valves 43 of the multiple compression systems 30 when the gas flow rate required by the load 3 changes from a state greater than 0% to 0%.

[0072] As a result, in each of the multiple compression systems 30, the gas in the supply line 31 is returned to the upstream side through the second recycle line 33. In this way, the gas remaining in the multiple compression systems 30 can be returned to the upstream tank 2, etc.

[0073] (8) Plants 1A and 1B according to an eighth aspect include the compressor systems 5A and 5B according to any one of (1) to (7), the tank 2, and the load 3.

[0074] This makes it possible to provide plants 1A, 1B equipped with compressor systems 5A, 5B that can reduce maintenance costs and the amount of energy consumption associated with driving the compressor 34.

[0075] (9) Plants 1A and 1B according to a ninth aspect are plants 1A and 1B of (8), in which the tank 2 stores hydrogen gas, and the load 3 is process equipment 3P that produces ammonia using hydrogen gas compressed by the compressor systems 5A and 5B.

[0076] This makes it possible to reduce the maintenance costs of the compressor systems 5A and 5B that compress hydrogen gas and the energy consumption associated with driving the compressors 34 in the plants 1A and 1B that produce ammonia from hydrogen gas.

[0077] (10) Plants 1A and 1B according to a tenth aspect are plants 1A and 1B according to (9), in which the tank 2 stores hydrogen gas generated from water in a water electrolysis device 2A.

[0078] This reduces the maintenance costs of the compressor systems 5A and 5B that compress the hydrogen gas produced from water in the water electrolysis apparatus 2A, and reduces the amount of energy consumed by driving the compressors 34.

[0079] The compressor system and plant disclosed herein can reduce maintenance costs and energy consumption associated with driving the compressor.

[0080] 1A, 1B Plant 2 Tank 2A ​​Water electrolysis device 2P Hydrogen production process 3 Load 3P Process equipment 5A, 5B Compressor system 30, 30A, 30B Compression line 31 Supply line 32 First recycle line 33 Second recycle line 34, 34A, 34B Compressor 35 Heat exchanger 41 First control valve 42 Second control valve 43 Third control valve 45 Check valve 60 Control unit 101 Upstream line 102 Downstream line

Claims

1. A compressor system that compresses gas supplied from a tank and supplies the gas to a load, the compressor system comprising: a compressor that compresses the gas supplied from the tank, and a supply line that supplies the gas compressed by the compressor to the load; a first recycle line that branches off from the supply line between the compressor and the load and is connected to merge with the supply line upstream of the compressor; a second recycle line that branches off from the supply line between the compressor and the load and is connected to merge with the supply line upstream of the compressor and upstream of the position where the first recycle line is connected to merge; a first control valve provided in the first recycle line; a second control valve provided in the second recycle line; and a third control valve provided in the supply line between the position where the second recycle line is connected to merge and the position where the first recycle line is connected to merge.

2. A compressor system according to claim 1, further comprising a control unit that controls the operation of the first control valve, the second control valve, and the third control valve, wherein the control unit closes the first control valve and opens the second control valve to an opening degree according to a request from the load when the flow rate of the gas supplied from the compression system to the load is greater than 0% and less than 100%.

3. A compressor system according to claim 1, further comprising a control unit that controls the operation of the first control valve, the second control valve, and the third control valve, wherein the control unit opens the first control valve and the second control valve and closes the third control valve when the flow rate of the gas supplied from the compression system to the load is reduced from a state greater than 0% to 0%.

4. The compressor system according to claim 1, comprising a plurality of said compression systems connected in parallel between said tank and said load.

5. A compressor system as described in claim 4, wherein the supply line is provided on a side closer to the load than the position where the first recycle line branches off and the position where the second recycle line branches off, with a check valve for preventing backflow of the gas from the load side to the compressor, the first recycle line and the second recycle line.

6. A compressor system according to claim 4 or 5, further comprising a control unit that controls operation of the first control valve, the second control valve, and the third control valve, wherein the control unit closes the third control valve of at least one of the plurality of compression systems, opens the third control valves of other of the plurality of compression systems, and opens at least one of the first control valve and the second control valve to an opening degree according to the load requirement, where N is the number of the plurality of compression systems, when the gas flow rate required by the load is greater than 0% and less than (100 / N) x (N-1)%.

7. A compressor system according to claim 4 or 5, further comprising a control unit that controls the operation of the first control valve, the second control valve, and the third control valve, wherein the control unit closes the third control valves of all of the plurality of compression systems when the gas flow rate required by the load changes from a state greater than 0% to 0%.

8. A plant comprising: the compressor system according to claim 1 or 5; the tank; and the load.

9. The plant according to claim 8, wherein the tank stores hydrogen gas, and the load is a process device that produces ammonia using the hydrogen gas compressed by the compressor system.

10. The plant according to claim 9, wherein the tank stores hydrogen gas produced from water in a water electrolysis device.

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