Compression system, chemical plant, and method for operating a compression system

Abstract

To provide a compression system which can reduce torque necessary for a restart of a compressor.SOLUTION: A compression system comprises: a fixed speed motor; a compressor which rotates by the fixed speed motor, and generates a compression gas by compressing a synthetic gas containing at least a first gas and a second gas; a first line for supplying the first gas constituting the synthetic gas to the compressor; a second line for supplying the second gas constituting the synthetic gas to the first line; a discharge line for making the compression gas discharged from the compressor circulate; a reflux line for refluxing a part of the compression gas to the first line from the discharge line; a first regulator valve which can regulate a flow rate of the first gas at the first line; a second regulator valve which can regulate a flow rate of the second gas at the second line; a discharge valve which can regulate a flow rate of the compression gas at the discharge line; a reflux valve which can regulate a flow rate of the compression gas at the reflux line; and a valve control device which can switch the first regulator valve, the second regulator valve, the discharge valve and the reflux valve on the basis of an operation state of the compressor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a compression system, a chemical plant, and a method of operating a compression system. [Background technology]

[0002] For example, Patent Document 1 discloses a compressor for compressing process gas such as LNG in a chemical plant and a control method thereof. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-85047 Summary of the Invention [Problem to be solved by the invention]

[0004] However, compressors may be forced to emergency shutdown due to some abnormality during operation. In such cases, the rotation of the compressor rotor may stop while process gas is still trapped inside the compressor. When the compressor is restarted in this state, the torque required to rotate the compressor rotor may be greater than the torque required to start the compressor.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a compression system, a chemical plant, and a method for operating a compression system that can reduce the torque required to restart a compressor. [Means for solving the problem]

[0006] In order to solve the above problem, a compression system according to the present disclosure includes: a fixed-speed motor; a compressor rotated by the fixed-speed motor and configured to compress a synthesis gas containing at least a first gas and a second gas to generate compressed gas; a first line connected to the compressor and configured to supply the first gas constituting a part of the synthesis gas to the compressor; a second line connected to the first line and configured to supply the second gas constituting a part of the synthesis gas to the first line; a discharge line connected to the compressor and configured to circulate the compressed gas discharged from the compressor; a reflux line connecting the discharge line and the first line and configured to reflux a part of the compressed gas from the discharge line to the first line; a first regulating valve configured to adjust the flow rate of the first gas in the first line; a second regulating valve configured to adjust the flow rate of the second gas in the second line; a discharge valve configured to adjust the flow rate of the compressed gas in the discharge line; and a valve control device including a determination unit that determines whether or not there is an abnormality in the compressor, a motor control unit that stops operation of the fixed speed motor when the determination unit determines that there is an abnormality in the compressor, and a switching processing unit that, when operation of the fixed speed motor is stopped, switches a fluid flow state of the first adjusting valve, the second adjusting valve, the discharge valve, and the reflux valve between a fully open state in which fluid can flow and a fully closed state in which fluid cannot flow, and the first gas has a first molecular weight, and the second gas has a second molecular weight that is smaller than the first molecular weight. When the operation of the fixed speed motor is stopped, the switching processing unit switches the first adjusting valve, the second adjusting valve, the discharge valve, and the return valve from the valve state during rated operation of the compressor to a first valve state, and in the first valve state, the first adjusting valve is switched from the fully open state, which is the valve state during the rated operation, to the fully closed state, the second adjusting valve and the discharge valve are maintained in the fully open state, which is the valve state during the rated operation, and the return valve is switched from the fully closed state, which is the valve state during the rated operation, to the fully open state.

[0007] A chemical plant according to the present disclosure also includes the compression system, a first gas supply source that generates the first gas and supplies the first gas to the first line, and a second gas supply source that generates the second gas and supplies the second gas to the second line.

[0008] a first line connected to the compressor and supplying the first gas constituting a part of the synthesis gas to the compressor; a second line connected to the first line and supplying the second gas constituting a part of the synthesis gas to the first line; a discharge line connected to the compressor and circulating the compressed gas discharged from the compressor; a reflux line connecting the discharge line and the first line and refluxing a part of the compressed gas from the discharge line to the first line; a first regulating valve capable of adjusting a flow rate of the first gas in the first line; a second regulating valve capable of adjusting a flow rate of the second gas in the second line; a discharge valve capable of adjusting a flow rate of the compressed gas in the discharge line; a motor control step of stopping operation of the fixed-speed motor when it is determined that there is an abnormality in the compressor; and a switching process step of switching a fluid flow state of the first adjustment valve, the second adjustment valve, the discharge valve, and the reflux valve between a fully open state in which fluid can flow and a fully closed state in which fluid cannot flow when the operation of the fixed-speed motor is stopped, wherein the first gas has a first molecular weight and the second gas has a second molecular weight that is smaller than the first molecular weight, and in the switching process step, when the operation of the fixed-speed motor is stopped, the first adjustment valve, the second adjustment valve, the discharge valve, and the reflux valve are switched from a valve state during rated operation of the compressor to a first valve state, and in the first valve state, the first adjustment valve is switched from the fully open state, which is the valve state during the rated operation, to the fully closed state, the second adjustment valve and the discharge valve are maintained in the fully open state, which is the valve state during the rated operation, and the reflux valve is switched from the fully closed state, which is the valve state during the rated operation, to the fully open state. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a compression system, a chemical plant, and a method for operating a compression system that can reduce the torque required to restart the compressor. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a compression system according to an embodiment of the present disclosure. [Figure 2] 1 is a functional block diagram showing a configuration of a valve control device according to an embodiment of the present disclosure. FIG. [Figure 3] 1 is a functional block diagram showing a configuration of a valve control device according to an embodiment of the present disclosure. FIG. [Figure 4] 3A and 3B are diagrams illustrating valve states of various valves that are switched by a switching processing unit of a valve control device according to an embodiment of the present disclosure. [Figure 5] 1 is a flowchart illustrating a method of operating a compression system according to an embodiment of the present disclosure. [Figure 6] FIG. 1 is a hardware configuration diagram illustrating a configuration of a computer according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a compression system, a chemical plant, and a method for operating a compression system according to an embodiment of the present disclosure will be described with reference to the drawings.

[0012] (Chemical Plant) The chemical plant is a green ammonia plant that produces ammonia. As shown in Fig. 1, the chemical plant 100 includes a compression system 1, a first gas supply source 20, and a second gas supply source 30.

[0013] (Compression System) The compression system 1 compresses a process gas (synthesis gas) as a working fluid generated, for example, within the chemical plant 100, and supplies the pressurized synthesis gas to a reaction device (not shown) such as a reactor that the chemical plant 100 has.

[0014] The compression system 1 includes a compression device 10, a first regulating valve 22, a first check valve 23, a second regulating valve 32, a second check valve 33, a discharge valve 41, a third check valve 42, a reflux line 50, a reflux valve 51, a valve control device 60, a first line 21, a second line 31, and a discharge line 40.

[0015] (Compression device) The compression device 10 compresses synthesis gas supplied from the outside and used in the chemical plant 100, and supplies the compressed synthesis gas to the reaction device. The compression device 10 has a fixed speed motor 11, a compressor 12, and a speed increaser 13. In this embodiment, the synthesis gas is generated by synthesizing different gases including at least a first gas and a second gas.

[0016] (fixed speed motor) The fixed-speed motor 11 is a drive source of the compressor 12 that generates power to drive the compressor 12 and rotates the compressor 12. The fixed-speed motor 11 rotates at a constant speed (fixed speed) when an external voltage is applied to it. The fixed-speed motor 11 has, for example, a motor stator as a stator and a motor rotor as a rotor having an output shaft 11a.

[0017] The motor stator is electrically connected to an external current supply source (not shown) of the fixed-speed motor 11. When a current flows through the coil of the motor stator, an electromagnetic force that rotates the motor rotor is generated. Therefore, when power is input from the outside to the motor stator of the fixed-speed motor 11, the output shaft 11a of the motor rotor rotates.

[0018] The output shaft 11a is a drive shaft that can rotate around an axis O that extends horizontally. Hereinafter, the direction in which this axis O extends will be simply referred to as the "axial direction Da." Furthermore, one side of the axial direction Da (the right side in FIG. 1) will be simply referred to as the "one side Dar," and the other side (the left side in FIG. 1) will be simply referred to as the "other side Dal."

[0019] (Compressor) The compressor 12 is a rotary machine that is rotated by the fixed speed motor 11 to compress the synthesis gas and generate compressed gas whose pressure has been increased to a predetermined value. The compressor 12 is disposed on one side Dar of the fixed speed motor 11. The compressor 12 has a compressor casing 12b and a compressor rotor 12a (rotor).

[0020] The compressor casing 12b is a member that forms the outer shell of the compressor 12. The compressor casing 12b is supported by a compressor support (not shown) that is fixed to the ground, a frame, or the like, and allows the synthesis gas to circulate inside. The compressor casing 12b has an intake port (not shown) for drawing in the synthesis gas and a discharge port (not shown) for discharging the compressed gas.

[0021] The compressor rotor 12a has a rotary shaft and a multi-stage impeller (not shown) fixed to the rotary shaft and forming a compression flow path for compressing the synthesis gas together with the inner surface of the compressor casing 12b.

[0022] The rotating shaft is a rotating shaft that can rotate around an axis O, similar to the output shaft 11a of the fixed speed motor 11. The rotating shaft is rotatably fixed to the compressor casing 12b via, for example, a bearing device, a sealing device, or the like.

[0023] The impellers in multiple stages are housed in a compressor casing 12b. The impellers are arranged on a rotary shaft so as to be aligned in the axial direction Da, and rotate around an axis O integrally with the rotary shaft.

[0024] The flow of synthesis gas introduced into compressor 12 will be described below. One end of a first line 21 extending from compression device 10 to the outside is connected to the suction port of compressor casing 12b of compressor 12. Synthesis gas is supplied from the outside to the inside of compressor casing 12b through this first line 21.

[0025] The synthesis gas introduced into the compressor casing 12b through the intake port is sequentially compressed by the multiple stages of impellers of the compressor rotor 12a rotating at high speed inside the compressor casing 12b. The synthesis gas is compressed to a predetermined pressure by the final stage impeller and then discharged to the outside of the compression device 10 through the discharge port of the compressor casing 12b.

[0026] One end of a discharge line 40 for discharging compressed gas is connected to the discharge port. The compressed gas inside the compressor casing 12b is supplied to the reaction device outside the compression device 10 through this discharge line 40.

[0027] In this embodiment, the compressor 12 and the fixed speed motor 11 are connected via a speed increaser 13. The speed increaser 13 is a variable speed increaser that increases the rotation speed of the rotating shaft of the compressor rotor 12a to be higher than the rotation speed of the output shaft 11a of the motor rotor of the fixed speed motor 11.

[0028] Specifically, an end portion on one side Dar of the output shaft 11a of the motor rotor and an end portion on the other side Dal of the rotation shaft of the compressor rotor 12a are each connected to gears of the speed increaser 13. With the speed increaser 13 as a boundary, the direction of rotation of the compressor rotor 12a of the compressor 12 about the axis O is opposite to the direction of rotation of the output shaft 11a of the motor 11 about the axis O.

[0029] Here, the first gas supply source 20 and the second gas supply source 30 provided in the chemical plant 100 will be described.

[0030] (First gas supply source) The first gas supply source 20 is a device that generates a first gas having a first molecular weight and supplies the generated first gas to the compressor 12 of the compression device 10. In this embodiment, the first gas supply source 20 is, for example, an air separation unit that separates only nitrogen (N2) from air by utilizing a difference in freezing point. The first gas supply source 20 supplies the nitrogen separated from air as the first gas to the compressor 12 of the compression device 10.

[0031] Here, the first gas supply source 20 and the compressor 12 of the compression device 10 are connected by the first line 21. That is, the one end of the first line 21 is connected to the suction port of the compressor 12, and the other end of the first line 21 is connected to the first gas supply source 20. Therefore, the first gas generated in the first gas supply source 20 is supplied to the compressor 12 through this first line 21.

[0032] (Second gas supply source) The second gas supply source 30 is a device that generates a second gas having a second molecular weight smaller than the first molecular weight and supplies the generated second gas into the first line 21. In this embodiment, the second gas supply source 30 is, for example, a device that separates only hydrogen (H) from water (HO) by electrolyzing the water. The second gas supply source 30 supplies the hydrogen separated from the water as the second gas into the first line 21.

[0033] Here, the second gas supply source 30 and the first line 21 are connected by the second line 31. One end of the second line 31 is connected to the second gas supply source 30, and the other end of the second line 31 is connected to the middle of the first line 21. Therefore, the second gas generated in the second gas supply source 30 is supplied to the first line 21 through this second line 31.

[0034] Therefore, synthesis gas is generated by the first gas and the second gas joining together in the first line 21. That is, the first gas and the second gas each constitute a part of the synthesis gas. Therefore, in this embodiment, the synthesis gas is not stored in advance, but is generated by mixing the first gas and the second gas in the first line 21 immediately before the compression device 10.

[0035] (First adjustment valve) The first regulating valve 22 is disposed midway through the first line 21. The first regulating valve 22 is a valve capable of adjusting the flow rate of the first gas flowing through the first line 21. In this embodiment, the first regulating valve 22 is an on / off valve capable of switching between a fully open state in which the first gas in the first line 21 can flow toward the compressor 12 and a fully closed state in which the first gas in the first line 21 cannot flow toward the compressor 12. The first regulating valve 22 is disposed in the first line 21 closer to the first gas supply source 20 than the connection position of the first line 21 with the second line 31.

[0036] (First check valve) The first check valve 23 is disposed midway through the first line 21. The first check valve 23 is a valve that prevents the first gas from flowing back in the first line 21 from the compressor 12 toward the first gas supply source 20. The first check valve 23 is disposed in the first line 21 between the first regulating valve 22 and the connection position of the first line 21 with the second line 31.

[0037] (Second adjusting valve) The second adjustment valve 32 is disposed midway through the second line 31. The second adjustment valve 32 is a valve capable of adjusting the flow rate of the second gas flowing through the second line 31. In this embodiment, the second adjustment valve 32 is an on / off valve capable of switching between a fully open state in which the second gas in the second line 31 can flow toward the first line 21 and a fully closed state in which the second gas in the second line 31 cannot flow toward the first line 21.

[0038] (Second check valve) The second check valve 33 is disposed midway through the second line 31. The second check valve 33 is a valve that prevents the second gas from flowing back through the first line 21 from the compressor 12 toward the second gas supply source 30 in the second line 31. The second check valve 33 is disposed in the second line 31 closer to the first line 21 than the second adjustment valve 32 in the second line 31.

[0039] (Discharge valve) The discharge valve 41 is disposed midway along the discharge line 40. The discharge valve 41 is a valve capable of adjusting the flow rate of the compressed gas flowing through the discharge line 40. The discharge valve 41 in this embodiment is an on / off valve that can be switched between a fully open state in which the compressed gas in the discharge line 40 can flow toward the reaction apparatus, and a fully closed state in which the compressed gas in the discharge line 40 cannot flow toward the reaction apparatus.

[0040] (Third check valve) The third check valve 42 is disposed midway through the discharge line 40. The third check valve 42 is a valve that prevents compressed gas from flowing back in the discharge line 40 toward the compressor 12. In this embodiment, the third check valve 42 is disposed on the discharge line 40 so as to sandwich the discharge valve 41 together with the compressor 12 on the discharge line 40.

[0041] (Reflux line) The reflux line 50 is disposed across the discharge line 40 and the first line 21. The reflux line 50 is an anti-surge line that can return the compressed gas flowing through the discharge line 40 to the first line 21. That is, the reflux line 50 allows the compressed gas discharged from the compressor 12 to merge with the synthesis gas introduced into the compressor 12.

[0042] One end of the reflux line 50 is connected to the discharge line 40 on the compressor 12 side closer to the discharge valve 41 in the discharge line 40, and the other end of the reflux line 50 is connected to the first line 21 on the compressor 12 side closer to the connection point between the first line 21 and the second line 31.

[0043] (reflux valve) The reflux valve 51 is disposed in the reflux line 50. The reflux valve 51 in this embodiment is a flow rate adjustment valve (anti-surge valve) that can adjust the flow rate of the compressed gas flowing through the reflux line 50 toward the first line 21.

[0044] (Valve control device) The valve control device 60 is a device that can switch the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 based on the operating status of the compressor 12. As shown in Fig. 2, the valve control device 60 has an acquisition unit 61, a determination unit 62, a motor control unit 63, and a switching processing unit 64.

[0045] (Acquisition Department) The acquisition unit 61 acquires status data of the compressor 12 at predetermined time intervals. Examples of the status data of the compressor 12 in this embodiment include the rotation speed of the compressor rotor 12a calculated based on the measurement results of a sensor included in the compressor 12, the temperature of the atmosphere in the compression flow path measured by a sensor disposed in the compressor 12, and the temperature of a bearing device that supports the rotating shaft of the compressor 12 measured by a sensor included in the bearing device.

[0046] Here, the rotation speed of the compressor rotor 12a is calculated, for example, by measuring the voltage applied to the fixed speed motor 11 with the above-mentioned sensor, based on the magnitude of the measured applied voltage and the gear ratio of the speed increaser 13.

[0047] Therefore, the acquisition unit 61 acquires status data of the compressor 12 from the various sensors described above via signal lines or the like. The acquisition unit 61 transmits the acquired status data to the determination unit 62. In the following, an example will be described in which the status data of the compressor 12 is the rotation speed of the compressor rotor 12a.

[0048] The acquisition unit 61 also acquires from the outside a signal indicating an instruction to start the fixed-speed motor 11. In this embodiment, the acquisition unit 61 receives, for example, a signal indicating an instruction to start transmitted from an external input interface of the valve control device 60. The acquisition unit 61 transmits the acquired signal to the motor control unit 63.

[0049] (Judgment Department) The determination unit 62 determines whether or not there is an abnormality in the compressor 12 based on the status data of the compressor 12 acquired by the acquisition unit 61. The determination unit 62 receives the status data from the acquisition unit 61. The determination unit 62 compares the received status data of the compressor 12 with predetermined thresholds (first threshold and second threshold) that the determination unit 62 stores in advance.

[0050] Specifically, the determination unit 62 compares the status data with a first threshold value that indicates a predetermined rated rotation speed. If the status data exceeds the first threshold value, the determination unit 62 determines that there is an abnormality in the compressor 12. In other words, if the rotation speed of the compressor rotor 12a has increased above the rated rotation speed, the determination unit 62 determines that there is an abnormality in the compressor 12.

[0051] If the status data does not exceed the first threshold value, the determination unit 62 determines that there is no abnormality in the compressor 12. In other words, if the rotation speed of the compressor rotor 12a is within the rated rotation speed, the determination unit 62 determines that there is no abnormality in the compressor 12. After completing the determination, the determination unit 62 transmits a signal indicating the presence or absence of an abnormality in the compressor 12 to the motor control unit 63 and the switching processing unit 64.

[0052] Furthermore, the determination unit 62 determines whether the compressor rotor 12a of the compressor 12 has stopped based on the status data of the compressor 12 acquired by the acquisition unit 61. If the status data indicates that the compressor rotor 12a is not rotating, the determination unit 62 determines that the rotation of the compressor rotor 12a has stopped. In this case, the determination unit 62 transmits a signal indicating that the compressor rotor 12a has stopped to the switching processing unit 64.

[0053] Furthermore, the determination unit 62 determines whether the compressor 12 is in a transition state after transmitting a signal indicating that the compressor rotor 12a is stopped to the switching processing unit 64. Specifically, the determination unit 62 compares the state data with a second threshold value indicating a predetermined rotation speed.

[0054] In this embodiment, the second threshold value is smaller than the first threshold value. When the status data exceeds the second threshold value, the determination unit 62 determines that the compressor 12 is in a transition state, transitioning from startup to rated operation. At this time, the determination unit 62 transmits a signal indicating that the compressor 12 is in a transition state to the switching processing unit 64.

[0055] (Motor control unit) The motor control unit 63 stops the operation of the fixed speed motor 11 when the determination unit 62 determines that there is an abnormality in the compressor 12. The motor control unit 63 receives a signal from the determination unit 62 indicating whether or not there is an abnormality in the compressor 12.

[0056] If the signal indicates that there is an abnormality in the compressor 12, the motor control unit 63 sends a signal indicating a stop instruction to the fixed speed motor 11. When the fixed speed motor 11 receives the signal indicating a stop instruction from the motor control unit 63, it stops rotating.

[0057] Furthermore, when the motor control unit 63 receives a signal indicating a start instruction from the acquisition unit 61, it starts the fixed-speed motor 11. Specifically, the motor control unit 63 simultaneously transmits a signal indicating a start instruction to the fixed-speed motor 11 and the switching processing unit 64. When the fixed-speed motor 11 receives the signal indicating a start instruction from the motor control unit 63, it starts rotating.

[0058] (Switching processing unit) When the operation of the fixed speed motor 11 is stopped, the switching processing unit 64 switches the fluid flow state of the first adjusting valve 22, the second adjusting valve 32, the discharge valve 41, and the return valve 51 between a fully open state in which the fluid can flow and a fully closed state in which the fluid cannot flow. Below, using Figure 3, the open / closed states corresponding to the valve states of each valve (first adjusting valve 22, second adjusting valve 32, discharge valve 41, return valve 51) operated by the switching processing unit 64 will be described.

[0059] The switching processing unit 64 receives a signal indicating the presence or absence of an abnormality in the compressor 12 from the determination unit 62. If the signal indicates that the compressor 12 is not abnormal, the switching processing unit 64 determines that the compressor 12 is in rated operation, and simultaneously transmits a signal indicating the “valve state during rated operation” to each of the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51.

[0060] The first adjusting valve 22 maintains the fully open state when it receives a signal indicating the valve state during rated operation from the switching processing unit 64. The second adjusting valve 32 maintains the fully open state when it receives a signal indicating the valve state during rated operation from the switching processing unit 64.

[0061] The discharge valve 41 maintains the fully open state when it receives a signal indicating the valve state during rated operation from the switching processing unit 64. The return valve 51 maintains the fully closed state when it receives a signal indicating the valve state during rated operation from the switching processing unit 64.

[0062] When the signal received from the judgment unit 62 indicates that there is an abnormality in the compressor 12, the switching processing unit 64 simultaneously sends a signal indicating the "first valve state" to each of the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51.

[0063] When the first adjusting valve 22 receives a signal indicating the first valve state from the switching processing unit 64, it switches from a fully open state, which is the valve state during rated operation, to a fully closed state. When the second adjusting valve 32 receives a signal indicating the first valve state from the switching processing unit 64, it maintains the fully open state, which is the valve state during rated operation.

[0064] The discharge valve 41 maintains the fully open state, which is the valve state during rated operation, when receiving a signal indicating the first valve state from the switching processing unit 64. The return valve 51 switches from the fully closed state, which is the valve state during rated operation, to the fully open state when receiving a signal indicating the first valve state from the switching processing unit 64.

[0065] In addition, when the signal received from the judgment unit 62 indicates that the compressor rotor 12a is stopped, the switching processing unit 64 simultaneously sends a signal indicating the "second valve state" to each of the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51.

[0066] The first adjusting valve 22 maintains the fully closed state, which is the first valve state, when it receives a signal indicating the second valve state from the switching processing unit 64. The second adjusting valve 32 switches from the fully open state, which is the first valve state, to the fully closed state, when it receives a signal indicating the second valve state from the switching processing unit 64.

[0067] The discharge valve 41 switches from the fully open state, which is the first valve state, to the fully closed state when receiving a signal indicating the second valve state from the switching processing unit 64. The return valve 51 maintains the fully open state, which is the first valve state, when receiving a signal indicating the second valve state from the switching processing unit 64.

[0068] In addition, when the signal received from the motor control unit 63 indicates a start instruction, the switching processing unit 64 simultaneously sends a signal indicating the "third valve state" to each of the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51.

[0069] The first adjusting valve 22 maintains the fully closed state, which is the second valve state, when it receives a signal indicating the third valve state from the switching processing unit 64. The second adjusting valve 32 switches from the fully closed state, which is the second valve state, to the fully open state, when it receives a signal indicating the third valve state from the switching processing unit 64.

[0070] When the discharge valve 41 receives a signal indicating the third valve state from the switching processing unit 64, the discharge valve 41 switches from the fully closed state, which is the second valve state, to the fully open state, or maintains the fully closed state. When the return valve 51 receives a signal indicating the third valve state from the switching processing unit 64, the return valve 51 maintains the fully open state, which is the second valve state.

[0071] In addition, when the signal received from the judgment unit 62 indicates that the compressor 12 is in a transition state, the switching processing unit 64 simultaneously sends a signal indicating the "fourth valve state" to each of the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51.

[0072] When the first adjusting valve 22 receives a signal indicating the fourth valve state from the switching processing unit 64, the first adjusting valve 22 changes from the fully closed state, which is the third valve state, to the fully closed state, which is the third valve state. Open When the second adjusting valve 32 receives a signal indicating the fourth valve state from the switching processing unit 64, it maintains the third valve state, which is the fully open state.

[0073] When the discharge valve 41 receives a signal indicating the fourth valve state from the switching processing unit 64, if the third valve state is the fully open state, the discharge valve 41 maintains the fully open state and switches to the third valve state. three When the valve state is in the fully closed state, the reflux valve 51 switches from the fully closed state to the fully open state when it receives a signal indicating the fourth valve state from the switching processing unit 64. Fully closed Switches to.

[0074] (Valve control device operation) Next, the operation of the valve control device 60 will be described with reference to FIG.

[0075] The acquisition unit 61 acquires status data of the compressor 12 (step S0). Next, the determination unit 62 determines whether or not there is an abnormality in the compressor 12 based on the status data acquired by the acquisition unit 61 (step S1). Next, if there is an abnormality in the compressor 12, Judgment section 62 If it is determined that the motor control unit 63 stops the operation of the fixed speed motor 11 (step S2).

[0076] Next, when the operation of the fixed speed motor 11 is stopped by the motor control unit 63, the switching processing unit 64 switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 from the valve state during rated operation to the first valve state (step S3).

[0077] Next, the determination unit 62 determines whether the compressor rotor 12a is stopped based on the state data acquired by the acquisition unit 61 (step S4). Next, when the determination unit 62 determines that the compressor rotor 12a is stopped, the switching processing unit 64 switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 from the first valve state to the second valve state (step S5).

[0078] Next, the acquisition unit 61 acquires a signal indicating an instruction to start the fixed-speed motor 11 from the outside and transmits it to the motor control unit 63 (step S6). Next, based on the signal indicating the instruction to start received from the acquisition unit 61, the motor control unit 63 starts the operation of the fixed-speed motor 11 (step S7).

[0079] Next, when the motor control unit 63 starts operation of the fixed speed motor 11, the switching processing unit 64 switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 from the second valve state to the third valve state (step S8).

[0080] Next, the determination unit 62 determines whether the compressor 12 is in the transition state (step S9). Next, when the determination unit 62 determines that the compressor 12 is in the transition state, the switching processing unit 64 switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 from the third valve state to the fourth valve state (step S10).

[0081] (Operation method of compression system) Next, an operation method of the compression system 1 will be described with reference to Fig. 5. The operation method includes a first acquisition step S11, an abnormality determination step S12, a first motor control step S13 (motor control step), a first switching processing step S14 (switching processing step), a stop determination step S15, a second switching processing step S16, a second acquisition step S17, a second motor control step S18, a third switching processing step S19, a transition determination step S20, and a fourth switching processing step S21.

[0082] (First acquisition process) The first acquisition step S11 is a step of acquiring status data of the compressor 12. In the first acquisition step S11, the acquisition unit 61 acquires status data of the compressor 12 measured by a sensor provided in the compressor 12.

[0083] (Abnormality determination process) The abnormality determination step S12 is a step subsequent to the first acquisition step S11, in which it is determined whether or not there is an abnormality in the compressor 12. In the abnormality determination step S12, the state data of the compressor 12 acquired in the first acquisition step S11 is compared with a predetermined threshold value stored in advance by the determination unit 62, and the determination unit 62 determines whether or not there is an abnormality in the compressor 12.

[0084] (First motor control process) The first motor control step S13 is a step that follows the abnormality determination step S12 and stops the operation of the fixed-speed motor 11. In the first motor control step S13, if it is determined in the abnormality determination step S12 that there is an abnormality in the compressor 12, the motor control unit 63 stops the operation of the fixed-speed motor 11.

[0085] (First switching process) The first switching processing step S14 is a step that follows the first motor control step S13 and switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 from their valve states during rated operation to the first valve state. In the first switching processing step S14, when the operation of the fixed speed motor 11 is stopped in the first motor control step S13, the switching processing unit 64 switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 from their valve states during rated operation to the first valve state.

[0086] (Stop judgment process) The stop determination step S15 is a step of determining whether or not the compressor rotor 12a has stopped, following the first switching processing step S14. In the stop determination step S15, the determination unit 62 determines whether or not the compressor rotor 12a has stopped, based on the status data acquired by the acquisition unit 61.

[0087] (Second switching process) The second switching process step S16 is a process following the stop determination process S15, in which the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the reflux valve 51 are switched from the first valve state to the second valve state. In the second switching process step S16, when it is determined in the stop determination process S15 that the compressor rotor 12a has stopped, the switching processing unit 64 switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the reflux valve 51 from the first valve state to the second valve state.

[0088] (Second acquisition process) The second acquisition step S17 is a step following the second switching processing step S16 of externally acquiring a signal indicating an instruction to start the fixed speed motor 11. In the second acquisition step S17, the signal indicating an instruction to start the fixed speed motor 11 is acquired from the outside by the acquisition unit 61.

[0089] (Second motor control process) The second motor control step S18 is a step following the second acquisition step S17, in which operation of the fixed-speed motor 11 is started. In the second motor control step S18, the motor control unit 63 starts operation of the fixed-speed motor 11 based on the signal indicating an instruction to start the fixed-speed motor 11 acquired in the second acquisition step S17.

[0090] (Third switching process) The third switching process step S19 is a process that follows the second motor control step S18 and switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 from the second valve state to the third valve state. In the third switching process step S19, when the fixed speed motor 11 is started in the second motor control step S18, the switching processing unit 64 switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 from the second valve state to the third valve state.

[0091] (Transition determination process) The transition determination step S20 is a step following the third switching processing step S19, in which it is determined whether or not the compressor 12 is in the transition state. In the transition determination step S20, the determination unit 62 determines whether or not the compressor 12 is in the transition state based on the state data acquired by the acquisition unit 61.

[0092] (Fourth switching process) The fourth switching process step S21 is a step of switching the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the reflux valve 51 from the third valve state to the fourth valve state following the transition determination step S20. fourth Switching process S21 When it is determined in the transition determination process S20 that the compressor 12 is in a transition state, the switching processing unit 64 switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 from the third valve state to the fourth valve state.

[0093] The compression system 1 is operated through the above series of steps.

[0094] (Action and effect) In the compression system 1 according to the above embodiment, when the judgment unit 62 in the valve control device 60 determines that there is an abnormality in the compressor 12, the switching processing unit 64 in the valve control device 60 transitions the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 from the valve state during rated operation to the first valve state.

[0095] As a result, when some abnormality occurs in the compressor 12 and the operation of the compressor 12 is stopped (when the compressor 12 trips), of the first gas and second gas that make up the synthesis gas, only the second gas, which has a smaller molecular weight, is supplied to the compressor 12 through the second line 31 and the first line 21.

[0096] In this embodiment, when the compressor 12 is stopped, the compressor rotor 12a does not stop simultaneously with the stopping of the compressor operation, but rather decreases in rotation speed toward the stopped state. Therefore, the second gas continues to be drawn into the compressor 12 as the compressor rotor 12a rotates.

[0097] Therefore, the proportion of the second gas in the compressor 12 can be increased relative to the first gas. In other words, the molecular weight of the synthesis gas present in the compressor 12 can be reduced. Therefore, the molecular weight of the gas present in the compressor 12 when the operation of the compressor 12 is stopped is reduced, so the torque required to restart the compressor 12 can be reduced. As a result, the fixed speed motor 11 can be made smaller.

[0098] Furthermore, in the compression system 1 according to the above embodiment, the first check valve 23 is disposed in the first line 21, the second check valve 33 is disposed in the second line 31, and the third check valve 42 is disposed in the discharge line 40. This makes it possible to prevent gas from flowing back even when, for example, the first adjusting valve 22, the second adjusting valve 32, and the discharge valve 41 are fully open while the compressor 12 is stopped.

[0099] Furthermore, in the compression system 1 according to the above embodiment, when the judgment unit 62 in the valve control device 60 determines that the rotation of the compressor rotor 12a of the compressor 12 has stopped, the switching processing unit 64 in the valve control device 60 transitions the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the return valve 51 from the first valve state to the second valve state.

[0100] As a result, the second gas is not newly introduced into the compressor 12 through the first line 21 and the second line 31. Furthermore, gases such as the first gas and the second gas are not discharged from the compressor 12 to other systems through the discharge line 40. Therefore, the proportion of the second gas in the compressor 12 can be kept constant.

[0101] Furthermore, in the compression system 1 according to the above embodiment, when the compressor 12 is started, the fixed speed motor 11 is started and the switching processing unit 64 in the valve control device 60 transitions the first adjusting valve 22, the second adjusting valve 32, the discharge valve 41, and the return valve 51 from the second valve state to the third valve state and then to the fourth valve state.

[0102] This allows the valve state to transition to that during rated operation while maintaining a low molecular weight of the gas inside the compressor 12, compared to a configuration of the compression system 1 that starts supplying synthesis gas to the compressor 12 upon restart. Therefore, the torque required to restart the compressor 12 can be further reduced.

[0103] In the chemical plant 100 according to the above embodiment, the first gas supply source 20 generates a first gas, and the generated first gas is supplied to the compressor 12 through a first line 21. Then, the second gas supply source 30 generates a second gas, and the generated second gas is supplied to the first line 21 through a second line 31.

[0104] As a result, compared to a configuration of chemical plant 100 that is equipped with a device that supplies a synthesis gas in which a first gas and a second gas are previously synthesized to compressor 12, when some abnormality occurs in compressor 12 and operation of compressor 12 is stopped, only the second gas can be supplied to compressor 12.

[0105] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to the configuration of the embodiment, and additions, omissions, substitutions, and other modifications to the configuration are possible within the scope that does not deviate from the gist of the present disclosure.

[0106] FIG. 6 is a hardware configuration diagram showing the configuration of the computer 1100 according to this embodiment. The computer 1100 includes a processor 1110 , a main memory 1120 , storage 1130 , and an interface 1140 .

[0107] The above-described valve control device 60 is implemented in a computer 1100. The operations of the above-described processing units are stored in the form of a program in a storage 1130. The processor 1110 reads the program from the storage 1130, loads it into the main memory 1120, and executes the above-described processing in accordance with the program. The processor 1110 also allocates storage areas in the main memory 1120 corresponding to the above-described storage units in accordance with the program.

[0108] The program may be for realizing part of the functions to be performed by the computer 1100. For example, the program may be for performing the functions by combining with another program already stored in the storage 1130 or by combining with another program installed in another device.

[0109] Furthermore, the computer 1100 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. ( Programmable Array Logic ) , GAL ( Generic Array Logic ) , CPLDs ( Complex Programmable Logic Device ) In this case, some or all of the functions implemented by the processor 1110 may be implemented by the integrated circuit.

[0110] Examples of storage 1130 include a magnetic disk, a magneto-optical disk, a semiconductor memory, etc. Storage 1130 may be an internal medium directly connected to the bus of computer 1100, or an external medium connected to computer 1100 via interface 1140 or a communication line.

[0111] Furthermore, when this program is distributed to the computer 1100 via a communication line, the computer 1100 that receives the program may load the program into the main memory 1120 and execute the above processing. In the above embodiment, the storage 1130 is a non-transitory tangible storage medium.

[0112] The program may also be a program for realizing part of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-described functions in combination with another program already stored in storage 1130.

[0113] Furthermore, the valve control device 60 described in the above embodiment may further include a storage unit in which the first threshold value and the second threshold value are stored. In this case, the determination unit 62 may not store the first threshold value and the second threshold value, but may determine whether or not there is an abnormality in the compressor 12 by referring to the first threshold value stored in the storage unit, and may determine whether or not the compressor 12 is in the transition state by referring to the second threshold value stored in the storage unit.

[0114] In addition, in the above embodiment, a configuration in which nitrogen (N2) is used as the first gas and hydrogen (H2) is used as the second gas is exemplified, but the present invention is not limited to this configuration. A configuration in which methane (CH4) is used as the first gas and hydrogen is used as the second gas may also be used. In this case, the compressor 12 may be, for example, a compressor 12 for compressing combustion gas used in a hydrogen-mixed combustion gas turbine in the chemical plant 100. It is only necessary that the first molecular weight of the first gas is larger than the second molecular weight of the second gas. Furthermore, the synthesis gas is only required to contain at least the first gas and the second gas, and may further contain other gases in addition to the first gas and the second gas.

[0115] Furthermore, in the above embodiment, a configuration has been described in which the second line 31 is connected to the first line 21, and the second gas flowing in the second line 31 merges with the first gas flowing in the first line 21 within the first line 21, but the present invention is not limited to this configuration. For example, the compression system 1 may further include a tank that is arranged midway through the first line 21 and connected to the second line 31 to combine the first gas and the second gas therein. In this case, the tank is arranged between the first check valve 23 in the first line 21 and the reflux line 50, and the second line 31 is not directly connected to the first line 21.

[0116] Furthermore, in the above embodiment, the judgment unit 62 judges whether or not there is an abnormality in the compressor 12, but this configuration is not limited to this, and the presence or absence of an abnormality may also be judged by visual inspection by an operator operating the compression system 1.

[0117] <Additional Notes> The compression system, the chemical plant, and the method of operating the compression system described in the embodiments can be understood, for example, as follows.

[0118] (1) A compression system 1 according to a first aspect includes a fixed-speed motor 11, a compressor 12 that is rotated by the fixed-speed motor 11 and compresses a synthesis gas containing at least a first gas and a second gas to generate compressed gas, a first line 21 that is connected to the compressor 12 and supplies the first gas that constitutes a part of the synthesis gas to the compressor 12, a second line 31 that is connected to the first line 21 and supplies the second gas that constitutes a part of the synthesis gas to the first line 21, and a discharge line 4 that is connected to the compressor 12 and distributes the compressed gas discharged from the compressor 12. a reflux line 50 connecting the discharge line 40 and the first line 21 and refluxing a portion of the compressed gas from the discharge line 40 to the first line 21; a first regulating valve 22 capable of adjusting the flow rate of the first gas in the first line 21; a second regulating valve 32 capable of adjusting the flow rate of the second gas in the second line 31; a discharge valve 41 capable of adjusting the flow rate of the compressed gas in the discharge line 40; a reflux valve 51 capable of adjusting the flow rate of the compressed gas in the reflux line 50; and a valve that controls the first regulating valve 22, the second regulating valve 32, and the discharge valve 41 based on the operating status of the compressor 12. and a valve control device 60 capable of switching the valve 41, and the reflux valve 51, wherein the valve control device 60 has a determination unit 62 that determines whether or not there is an abnormality in the compressor 12, a motor control unit 63 that stops operation of the fixed speed motor 11 when the determination unit 62 determines that there is an abnormality in the compressor 12, and a switching processing unit 64 that, when operation of the fixed speed motor 11 is stopped, switches the fluid flow state of the first adjusting valve 22, the second adjusting valve 32, the discharge valve 41, and the reflux valve 51 between a fully open state in which fluid can flow and a fully closed state in which fluid cannot flow. the second gas has a first molecular weight that is smaller than the first molecular weight, and the switching processing unit 64 switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the reflux valve 51 from a valve state during rated operation of the compressor 12 to a first valve state when the operation of the fixed speed motor 11 is stopped, and in the first valve state, the first regulating valve 22 is switched from the fully open state that is the valve state during the rated operation to the fully closed state, the second regulating valve 32 and the discharge valve 41 are maintained in the fully open state that is the valve state during the rated operation, and the reflux valve 51 isThe valve state during rated operation is switched from the fully closed state to the fully open state.

[0119] As a result, when some abnormality occurs in the compressor 12 and the operation of the compressor 12 is stopped, of the first gas and second gas that make up the synthesis gas, only the second gas, which has a smaller molecular weight, is supplied to the compressor 12 through the second line 31 and the first line 21.

[0120] (2) The compression system 1 according to the second aspect may be the compression system 1 of (1), further comprising a first check valve 23 that prevents the first gas from flowing back from the compressor 12 to the first line 21, a second check valve 33 that prevents the second gas from flowing back from the compressor 12 to the second line 31, and a third check valve 42 that prevents the compressed gas in the discharge line 40 from flowing back to the compressor 12.

[0121] This prevents gas from flowing back even when, for example, the first regulating valve 22, the second regulating valve 32, and the discharge valve 41 are fully open while the compressor 12 is stopped.

[0122] (3) A compression system 1 according to a third aspect is the compression system 1 according to (1) or (2), wherein the switching processing unit 64 switches the first regulating valve 22, the second regulating valve 32, the discharge valve 41, and the reflux valve 51 from the first valve state to a second valve state when the rotation of the rotor of the compressor 12 stops after the operation of the fixed speed motor 11 is stopped. 2 is , the fully closed state is maintained, and the discharge valve 41 and the second adjusting valve 32 may be switched from the fully open state to the fully closed state, and the reflux valve 51 may be maintained in the fully open state.

[0123] As a result, no new second gas is introduced into the compressor 12 through the first line 21 and the second line 31, and gases such as the first gas and the second gas are not discharged from the compressor 12 to other systems through the discharge line 40.

[0124] (4) A compression system 1 according to a fourth aspect is the compression system 1 of (3), wherein, when the compressor 12 is operated, the switching processing unit 64 starts the fixed speed motor 11 and switches the first adjustment valve 22, the second adjustment valve 32, the discharge valve 41, and the return valve 51 from the second valve state to a third valve state and then to a fourth valve state, wherein in the third valve state, the first adjustment valve 22 is maintained in the fully closed state, the second adjustment valve 32 is switched from the fully closed state to the fully open state, and the return valve 51 is maintained in the fully open state; and in the fourth valve state, the first adjustment valve 22 is switched from the fully closed state to the fully open state, the second adjustment valve 32 is maintained in the fully open state, the discharge valve 41 is switched from the fully closed state to the fully open state, and the return valve 51 is switched from the fully open state to reduce the flow rate.

[0125] This allows the valve state to be transitioned to that during rated operation while the molecular weight of the gas inside the compressor 12 is maintained low.

[0126] (5) A chemical plant 100 according to a fifth aspect includes a compression system 1 according to any one of (1) to (4), a first gas supply source 20 that generates the first gas and supplies the first gas to the first line 21, and a second gas supply source 30 that generates the second gas and supplies the second gas to the second line 31.

[0127] As a result, compared to a configuration of chemical plant 100 equipped with a device that supplies a synthesis gas in which the first gas and the second gas are pre-synthesized to compressor 12, when some abnormality occurs in compressor 12 and operation of compressor 12 is stopped, only the second gas can be supplied to compressor 12.

[0128] (6) A method of operating a compression system 1 according to a sixth aspect includes a fixed-speed motor 11, a compressor 12 that is rotated by the fixed-speed motor 11 and compresses a synthesis gas containing at least a first gas and a second gas to generate compressed gas, a first line 21 that is connected to the compressor 12 and supplies the first gas that constitutes a part of the synthesis gas to the compressor 12, a second line 31 that is connected to the first line 21 and supplies the second gas that constitutes a part of the synthesis gas to the first line 21, and a compressor 12 that supplies the compressed gas discharged from the compressor 12. a reflux line (50) connecting the discharge line (40) and the first line (21) and refluxing a portion of the compressed gas from the discharge line (40) to the first line (21); a first regulating valve (22) capable of adjusting the flow rate of the first gas in the first line (21); a second regulating valve (32) capable of adjusting the flow rate of the second gas in the second line (31); a discharge valve (41) capable of adjusting the flow rate of the compressed gas in the discharge line (40); and a reflux valve (51) capable of adjusting the flow rate of the compressed gas in the reflux line (50), the method comprising: The method includes an abnormality determination step S12 of determining whether or not there is an abnormality in the compressor 12, a motor control step of stopping operation of the fixed speed motor 11 when it is determined that there is an abnormality in the compressor 12, and a switching process step of switching a fluid flow state in the first adjustment valve 22, the second adjustment valve 32, the discharge valve 41, and the reflux valve 51 between a fully open state in which fluid can flow and a fully closed state in which fluid cannot flow when the operation of the fixed speed motor 11 is stopped, wherein the first gas has a first molecular weight, and the second gas has a second molecular weight smaller than the first molecular weight, In step 10, when the operation of the fixed speed motor 11 is stopped, the first adjustment valve 22, the second adjustment valve 32, the discharge valve 41, and the return valve 51 are switched from the valve state during rated operation of the compressor 12 to a first valve state, and in the first valve state, the first adjustment valve 22 is switched from the fully open state, which is the valve state during rated operation, to the fully closed state, the second adjustment valve 32 and the discharge valve 41 are maintained in the fully open state, which is the valve state during rated operation, and the return valve 51 is switched from the fully closed state, which is the valve state during rated operation, to the fully open state. [Explanation of symbols]

[0129] 1...Compression system 10...Compression device 11...Fixed speed motor 11a...Output shaft 12...Compressor 12a...Compressor rotor 12b...Compressor casing 13...Step-up gear 20...First gas supply source 21...First line 22...First regulating valve 23...First check valve 30...Second gas supply source 31...Second line 32...Second regulating valve 33...Second check valve 40...Discharge line 41...Discharge valve 42...Third check valve 50...Reflux line 51...Reflux valve 60...Valve control device 61...Acquisition unit 62...Determination unit 63...Motor control unit 64...Switching processing unit 100...Chemical plant 1100...Computer 1110...Processor 1120...Main memory 1130...Storage 1140...Interface Da...Axial direction Dar...One side Dal...Other side O...Axial line S11...First acquisition process S12: Abnormality determination step S13: First motor control step S14: First switching process step S15: Stop determination step S16: Second switching process step S17: Second acquisition step S18: Second motor control step S19: Third switching process step S20: Transition determination step S21: Fourth switching process step

Claims

1. a fixed speed motor; a compressor rotated by the fixed speed motor and configured to compress a synthesis gas including at least a first gas and a second gas to produce a compressed gas; a first line connected to the compressor for supplying the first gas constituting a portion of the synthesis gas to the compressor; a second line connected to the first line and supplying the second gas constituting a part of the synthesis gas to the first line; a discharge line connected to the compressor and through which the compressed gas discharged from the compressor flows; a reflux line connecting the discharge line and the first line and allowing a portion of the compressed gas to reflux from the discharge line to the first line; a first adjusting valve capable of adjusting a flow rate of the first gas in the first line; a second adjusting valve capable of adjusting a flow rate of the second gas in the second line; a discharge valve capable of adjusting the flow rate of the compressed gas in the discharge line; a reflux valve capable of adjusting the flow rate of the compressed gas in the reflux line; a valve control device that can switch the first regulating valve, the second regulating valve, the discharge valve, and the return valve based on an operating state of the compressor; Equipped with The valve control device a determination unit that determines whether or not there is an abnormality in the compressor; a motor control unit that stops operation of the fixed speed motor when the determination unit determines that an abnormality has occurred in the compressor; a switching processing unit that switches a fluid flow state of the first adjusting valve, the second adjusting valve, the discharge valve, and the reflux valve between a fully open state in which fluid can flow and a fully closed state in which fluid cannot flow when the operation of the fixed speed motor is stopped; and the first gas has a first molecular weight; the second gas has a second molecular weight that is less than the first molecular weight; the switching processing unit switches the first adjusting valve, the second adjusting valve, the discharge valve, and the return valve from a valve state during rated operation of the compressor to a first valve state when operation of the fixed speed motor is stopped, In the first valve state, the first adjusting valve is switched from the fully open state, which is a valve state during the rated operation, to the fully closed state, the second adjusting valve and the discharge valve are maintained in the fully open state, which is the valve state during the rated operation, The compression system, wherein the reflux valve is switched from the fully closed state, which is the valve state during the rated operation, to the fully open state.

2. 2. The compression system of claim 1, further comprising: a first check valve that prevents the first gas from flowing back from the compressor into the first line; a second check valve that prevents the second gas from flowing back from the compressor into the second line; and a third check valve that prevents the compressed gas in the discharge line from flowing back to the compressor.

3. The switching processing unit when the rotor of the compressor stops rotating after the fixed speed motor stops operating, the first regulating valve, the second regulating valve, the discharge valve, and the reflux valve are switched from the first valve state to a second valve state; In the second valve state, The first adjusting valve is maintained in the fully closed state, the discharge valve and the second adjustment valve are switched from the fully open state to the fully closed state, The compression system according to claim 1 or 2, wherein the reflux valve is maintained in the fully open state.

4. The switching processing unit When the compressor is operated, the fixed speed motor is started, and the first adjusting valve, the second adjusting valve, the discharge valve, and the return valve are switched from the second valve state to a third valve state and then to a fourth valve state, in this order; In the third valve state, The first adjusting valve is maintained in the fully closed state, the second adjusting valve is switched from the fully closed state to the fully open state, the discharge valve is switched from the fully closed state to the fully open state or is maintained in the fully closed state; The reflux valve is maintained in the fully open state, In the fourth valve state, the first adjusting valve is switched from the fully closed state to the fully open state, The second adjusting valve is maintained in the fully open state, When the discharge valve is in the fully open state, it maintains the fully open state, and when the discharge valve is in the fully closed state, it switches from the fully closed state to the fully open state, The compression system of claim 3 , wherein the reflux valve is switchable from the fully open state to the fully closed state.

5. A compression system according to any one of claims 1 to 4; A chemical plant comprising: a first gas supply source that generates the first gas and supplies the first gas to the first line; and a second gas supply source that generates the second gas and supplies the second gas to the second line.

6. a fixed speed motor; a compressor rotated by the fixed speed motor and configured to compress a synthesis gas including at least a first gas and a second gas to produce a compressed gas; a first line connected to the compressor for supplying the first gas constituting a portion of the synthesis gas to the compressor; a second line connected to the first line and supplying the second gas constituting a part of the synthesis gas to the first line; a discharge line connected to the compressor and through which the compressed gas discharged from the compressor flows; a reflux line connecting the discharge line and the first line and allowing a portion of the compressed gas to reflux from the discharge line to the first line; a first adjusting valve capable of adjusting a flow rate of the first gas in the first line; a second adjusting valve capable of adjusting a flow rate of the second gas in the second line; a discharge valve capable of adjusting the flow rate of the compressed gas in the discharge line; a reflux valve capable of adjusting the flow rate of the compressed gas in the reflux line; A method of operating a compression system comprising: an abnormality determination step of determining whether or not there is an abnormality in the compressor; a motor control step of stopping operation of the fixed speed motor when it is determined that an abnormality has occurred in the compressor; a switching process step for switching a fluid flow state of the first adjusting valve, the second adjusting valve, the discharge valve, and the reflux valve between a fully open state in which fluid can flow and a fully closed state in which fluid cannot flow when the operation of the fixed speed motor is stopped; Including, the first gas has a first molecular weight; the second gas has a second molecular weight that is less than the first molecular weight; In the switching process, when the operation of the fixed speed motor is stopped, the first adjusting valve, the second adjusting valve, the discharge valve, and the return valve are switched from a valve state during rated operation of the compressor to a first valve state, In the first valve state, the first adjusting valve is switched from the fully open state, which is a valve state during the rated operation, to the fully closed state, the second adjusting valve and the discharge valve are maintained in the fully open state, which is the valve state during the rated operation, The method for operating a compression system includes switching the reflux valve from the fully closed state, which is the valve state during the rated operation, to the fully open state.

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