Multistage compression system of methanol preparation production line and methanol preparation production line

Abstract

The invention relates to the technical field of methanol preparation and production, and provides a multi-stage compression system of a methanol preparation production line and the methanol preparation production line. The multi-stage compression system comprises a compressor unit, an initial pressure detector and a compression control system; an outlet of the compressor unit is used for being communicated with a methanol synthesis device, the initial pressure detector is used for detecting the hydrogen pressure in the hydrogen buffer tank so as to detect the initial pressure of hydrogen prepared by the electrolytic hydrogen production assembly, and the compression control system is in communication connection with the initial pressure detector and the compressor unit. The compression control system is used for controlling the number of the compressors participating in hydrogen compression in the compressor unit according to the initial pressure, and the number of the compressors participating in hydrogen compression in the compressor unit is inversely proportional to the initial pressure, so that the compressor unit pressurizes different initial pressures to target pressures.

Description

Technical Field

[0001] This application relates to the field of methanol production technology, specifically to a multi-stage compression system and a methanol production line. Background Technology

[0002] Methanol is a clean and renewable fuel with increasing applications. Current technologies typically produce hydrogen by electrolyzing water using renewable energy, and then synthesize methanol from hydrogen and carbon dioxide. This method of methanol production effectively utilizes renewable energy, reduces dependence on fossil fuels, and lowers greenhouse gas emissions.

[0003] Hydrogen compressors are important equipment in the methanol production process. They are used to compress hydrogen to a target pressure, which is then used in methanol synthesis. This improves the reaction rate and efficiency of hydrogen, enabling efficient methanol production.

[0004] However, during the methanol production process, the hydrogen generation pressure fluctuates significantly due to the instability of renewable energy supply such as solar and wind power. This unstable hydrogen supply leads to large fluctuations in the inlet pressure of the hydrogen compressor. Since the hydrogen compressor can only compress hydrogen to a limited final pressure, it is difficult to cope with the unstable hydrogen supply. If the compressed hydrogen pressure must reach the target pressure, the hydrogen compressor needs to bear a large compression ratio, resulting in extremely high energy consumption and cost, as well as low efficiency. Summary of the Invention

[0005] In view of this, this application provides a multi-stage compression system and a methanol production line for methanol production, in order to solve the problem in the prior art that the hydrogen compressor inlet pressure fluctuates greatly during the methanol production process, and the hydrogen compressor is unable to cope with the unstable hydrogen supply.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] A multi-stage compression system for a methanol production line includes:

[0008] The compressor unit has its inlet connected to the outlet of the hydrogen buffer tank of the electrolytic hydrogen production unit, and its outlet is connected to the methanol synthesis unit.

[0009] An initial pressure detector is used to detect the hydrogen pressure inside the hydrogen buffer tank, so as to detect the initial pressure of the hydrogen produced by the electrolytic hydrogen production assembly.

[0010] The compression control system is communicatively connected to the initial pressure detector and the compressor unit, wherein:

[0011] The compression control system is used to control the number of compressors participating in hydrogen compression in the compressor group according to the initial pressure, and the number of compressors participating in hydrogen compression in the compressor group is inversely proportional to the initial pressure, so that the compressor group pressurizes different initial pressures to the target pressure.

[0012] Optionally, the compressor unit includes multiple compressors connected in series and multiple connecting pipe sections. The first ports of all the connecting pipe sections are connected in parallel to the outlet end of the hydrogen buffer tank, and the second ports of all the connecting pipe sections are connected one-to-one to the inlet end of each of the compressors, so that the compressor unit forms multiple parallel optional paths, and the number of compressors in each optional path is different.

[0013] Each of the connecting pipe sections is equipped with a shut-off valve, and all of the shut-off valves are communicatively connected to the compression control system, wherein:

[0014] The compression control system is used to control the switching of each of the shut-off valves according to the initial pressure, and to open one of the optional passages while closing the other optional passages.

[0015] Optionally, the multi-stage compression system further includes a compression ratio adjustment mechanism, which is communicatively connected to the compression control system and all compressors in the compressor unit, wherein:

[0016] The compression control system is used to control the compression ratio adjustment mechanism according to the number of compressors in the selected circuit and the initial pressure, so as to adjust the compression ratio of each compressor in the selected circuit.

[0017] Optionally, the compressor unit further includes a separator for gas-liquid separation. Along the gas flow direction, each compressor in the compressor unit has an upstream separator. Each separator has a drain assembly, which is communicatively connected to the compression control system. The compression control system controls the on / off state of the drain assembly connected to each separator based on the liquid level in each separator; and / or,

[0018] The compressor unit also includes a cooler, and the cooler is provided between any two adjacent compressors in the compressor unit.

[0019] Optionally, the multi-stage compression system further includes an alarm element, which is communicatively connected to the compression control system. The compression control system is used to monitor the status of each compressor in the compressor unit, wherein:

[0020] In the event of a failure of a compressor involved in hydrogen compression in the compressor unit, the compression control system controls all compressors in the compressor unit to stop operating and controls the connection between the compressor unit inlet and the outlet of the hydrogen buffer tank to be cut off.

[0021] In the event of a malfunction in a compressor that is not involved in hydrogen compression within the compressor unit, the compression control system controls the alarm element to issue an alarm signal.

[0022] Optionally, the multi-stage compression system further includes:

[0023] A renewable energy power generation device can be electrically connected to the electrolyzer of the hydrogen electrolysis assembly;

[0024] A backup power supply can be electrically connected to the electrolyzer of the hydrogen production assembly.

[0025] A predictive control system is used to acquire forecast information on renewable energy sources and to predict the availability of renewable energy sources within a preset time period based on the forecast information, wherein:

[0026] During the predetermined future period, if the availability of renewable energy is lower than the predetermined availability, the backup power supply will supply power to the electrolyzer.

[0027] Within the predetermined future timeframe, if the availability of renewable energy is greater than or equal to the predetermined availability, the renewable energy power generation device will supply power to the electrolyzer, and the backup power supply will cease supplying power to the electrolyzer.

[0028] Optionally, the power output terminal of the renewable energy power generation device and the backup power supply are electrically connected to the electrolyzer via a dual-power automatic transfer switch. During the preset future time period, if the availability of renewable energy is lower than the preset availability, the renewable energy power generation device will stop supplying power to the electrolyzer; or...

[0029] The power output terminal of the renewable energy power generation device and the backup power supply are connected in parallel to the electrolytic cell. During the preset future time period, when the availability of renewable energy is lower than the preset availability, the renewable energy power generation device and the backup power supply will supply power to the electrolytic cell.

[0030] Optionally, the predictive control system includes a data processing module and a predictive controller, wherein the data processing module is used to collect future weather forecast information.

[0031] The predictive controller is used to predict the predicted pressure of hydrogen in the hydrogen buffer tank within a preset future time period based on the future weather forecast information. If the predicted pressure is less than the preset pressure, the renewable energy availability is lower than the preset availability; if the predicted pressure is greater than or equal to the preset pressure, the renewable energy availability is greater than or equal to the preset availability; and / or,

[0032] The forecast controller is used to predict the predicted power generation of the renewable energy power generation device within the future preset time period based on the future weather forecast information. If the predicted power generation is less than the preset power generation, the renewable energy availability is lower than the preset availability. If the predicted power generation is greater than or equal to the preset power generation, the renewable energy availability is greater than or equal to the preset availability.

[0033] Optionally, if the initial pressure is greater than or equal to a preset pressure and continues to decrease, the predictive control system predicts the availability of renewable energy within the preset future time period;

[0034] When the initial pressure is greater than or equal to the preset pressure and is not in a state of continuous decrease, the predictive control system stops predicting the availability of renewable energy within the preset time period, and the renewable energy power generation device supplies power to the electrolyzer, while the backup power supply stops supplying power to the electrolyzer.

[0035] When the initial pressure is less than the preset pressure, the renewable energy power generation device supplies power to the electrolytic cell, and the backup power supply stops supplying power to the electrolytic cell.

[0036] A methanol production line, comprising any of the above-mentioned multi-stage compression systems.

[0037] In this embodiment, the compression control system can dynamically control the number of compressors participating in hydrogen compression in the compressor unit based on the real-time initial pressure value. This addresses pressure fluctuations at the compressor unit inlet, pressurizing hydrogen with different initial pressures to the target pressure, thus achieving flexibility and efficiency in adjusting the hydrogen pressure at the outlet of the multi-stage compression system. Therefore, the multi-stage compression system for the methanol production line disclosed in this embodiment can solve the problem in the prior art where, during methanol production, the hydrogen compressor inlet pressure fluctuates significantly, making it difficult for the hydrogen compressor to cope with unstable hydrogen supply. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of a multi-stage compression system provided in an embodiment of this application;

[0040] Figure 2 A block diagram illustrating the operation process of a multi-level compression system provided in an embodiment of this application.

[0041] exist Figures 1-2 middle:

[0042] 01. Electrolyzer; 02. Hydrogen buffer tank; 03. Initial pressure detector; 04. Hydrogen buffer tank outlet shut-off valve; 05. Second and third connecting pipe section shut-off valve; 06. Outlet thermometer; 07. End pressure detector; 08. Compressor unit outlet shut-off valve;

[0043] 10. First separator; 11. First compressor; 12. First cooler; 13. First shut-off valve; 14. First pressure transmitter; 15. First temperature transmitter; 16. First flow meter; 17. First flow regulating valve; 18. First local level gauge; 19. First remote level gauge; 101. First level regulating valve;

[0044] 20. Second separator; 21. Second compressor; 22. Second cooler; 23. Second shut-off valve; 24. Second pressure transmitter; 25. Second temperature transmitter; 26. Second flow meter; 27. Second flow regulating valve; 28. Second local level gauge; 29. ​​Second remote level gauge; 201. Second level regulating valve;

[0045] 30. Third separator; 31. Third compressor; 32. Third shut-off valve; 33. Third pressure transmitter; 34. Third temperature transmitter; 35. Third flow meter; 36. Third flow regulating valve; 37. Third local level gauge; 38. Third remote level gauge; 39. Third level regulating valve;

[0046] 40. Wind power generation equipment; 41. Photovoltaics;

[0047] 50. Main drain pipe;

[0048] 60. Safety valve outlet main pipe;

[0049] 70. Inlet and outlet heat exchangers of the methanol synthesis unit. Detailed Implementation

[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] like Figures 1-2 As shown in the illustration, this application provides a multi-stage compression system for a methanol production line. This multi-stage compression system includes an electrolysis hydrogen production assembly, a compressor unit, an initial pressure detector 03, and a compression control system.

[0052] The hydrogen electrolysis assembly includes an electrolyzer 01, which is electrically connected to a power supply unit. The electrolyzer 01 uses electrical energy provided by the power supply unit to electrolyze water to produce hydrogen. Optionally, the power supply unit can be a renewable energy power generation unit or other device capable of providing electrical energy.

[0053] Water is electrolyzed in electrolytic cell 01, producing hydrogen and oxygen at the cathode and anode respectively. Electrolytic cell 01 has a hydrogen outlet, through which hydrogen is discharged.

[0054] The electrolytic hydrogen production unit also includes a hydrogen buffer tank 02. The inlet of the hydrogen buffer tank 02 is connected to the hydrogen outlet of the electrolyzer 01. The hydrogen produced by the electrolysis of water in the electrolyzer 01 is stored in the hydrogen buffer tank 02. (When the power supply is a renewable energy power generation device, and the renewable energy is completely or partially unavailable, the hydrogen buffer tank 02 can replace part of the hydrogen production to maintain the supply of green hydrogen to green methanol production for a period of time. Alternatively, when other power supply devices are used, but the power supply device suddenly stops supplying power to the electrolyzer 01, the hydrogen buffer tank 02 can maintain the supply for a period of time.)

[0055] The multi-stage compression system includes a compressor unit. The inlet of the compressor unit is connected to the outlet of the hydrogen buffer tank 02. The outlet of the compressor unit is connected to the methanol synthesis unit to deliver the pressurized hydrogen to the feed gas mixing unit of the methanol synthesis unit. Optionally, a reciprocating piston compressor can be used.

[0056] The initial pressure detector 03 is used to detect the hydrogen pressure inside the hydrogen buffer tank 02, thereby detecting the initial pressure of the hydrogen produced by the electrolytic hydrogen production assembly. The initial pressure detector 03 can be located within the hydrogen buffer tank 02. Alternatively, in other optional embodiments, the initial pressure detector 03 can also be located on the connecting pipe between the outlet of the hydrogen buffer tank 02 and the inlet of the compressor unit. The initial pressure detector 03 can be a pressure transmitter or other components capable of detecting hydrogen pressure; this application does not impose any limitations on this.

[0057] The compression control system is communicatively connected to the initial pressure detector 03 and the compressor unit. The initial pressure detector 03 can transmit the detected initial pressure to the compression control system. The compression control system is used to control the number of compressors participating in hydrogen compression in the compressor unit according to the initial pressure. The number of compressors participating in hydrogen compression in the compressor unit is inversely proportional to the initial pressure, so that the compressor unit can pressurize different initial pressures to the target pressure. In other words, the compression control system controls the number of compressors participating in hydrogen compression in the compressor unit according to the pressure difference between the initial pressure and the target pressure that the compressor unit needs to pressurize the hydrogen to, so as to maintain the pressure at the outlet of the compressor unit at a relatively stable target pressure.

[0058] For example, when the initial pressure is low and the pressure difference between the initial pressure and the target pressure is large, the compression control system can control all compressors to participate in the hydrogen compression operation. Through the coordinated action of multiple compressors, the hydrogen pressure at the outlet of the compressor unit can be guaranteed to reach the target pressure. When the initial pressure is high and the pressure difference between the initial pressure and the target pressure is small, the compression control system can control some (e.g., one) compressors in the compressor unit to compress the hydrogen, while the remaining compressors do not compress the hydrogen, in order to prevent the compressor unit from over-pressurizing the hydrogen.

[0059] Optionally, the initial pressure detector 03 and each compressor in the compressor unit can communicate with the compression control system via wired, wireless, or Bluetooth connections.

[0060] In this embodiment, the compression control system can dynamically control the number of compressors participating in hydrogen compression in the compressor unit based on the real-time initial pressure value. This addresses pressure fluctuations at the compressor unit inlet, pressurizing hydrogen with different initial pressures to the target pressure, thus achieving flexibility and efficiency in adjusting the hydrogen pressure at the outlet of the multi-stage compression system. Therefore, the multi-stage compression system for the methanol production line disclosed in this embodiment can solve the problem in the prior art where, during methanol production, the hydrogen compressor inlet pressure fluctuates significantly, making it difficult for the hydrogen compressor to cope with unstable hydrogen supply.

[0061] Furthermore, by dynamically controlling the number of compressors involved in hydrogen compression in the compressor unit based on the real-time initial pressure value, and addressing pressure fluctuations at the compressor unit inlet, the existing technology using a single-stage compressor can alleviate the problem that insufficient compressor inlet pressure leads to the compressor outlet pressure failing to reach the target pressure, thus requiring the entire methanol production line to be shut down. This effectively reduces the downtime cost of the methanol production line.

[0062] There are several ways for the compression control system to control the number of compressors participating in hydrogen compression in the compressor unit. In one optional embodiment, each compressor in the compressor unit can be connected to the compression control system. The compression control system can control the start and stop of each compressor according to the initial pressure. When hydrogen flows through a compressor that is not running, the compressor does not pressurize the hydrogen, thereby controlling the number of compressors participating in hydrogen compression in the compressor unit.

[0063] In another alternative embodiment, the compressor unit includes multiple compressors connected in series and multiple connecting pipe sections. The first port of all connecting pipe sections is connected in parallel to the outlet of the hydrogen buffer tank, and the second port of all connecting pipe sections is connected one-to-one to the inlet of each compressor, so that the compressor unit forms multiple parallel optional paths, and the number of compressors in each optional path is different.

[0064] All connecting pipe sections are equipped with shut-off valves, all of which are communicatively connected to the compression control system. The compression control system controls the opening and closing of each shut-off valve based on the initial pressure, and enables one optional path to be open while the others are closed. The compression control system also controls the shutdown of compressors not involved in hydrogen compression, extending compressor lifespan and reducing energy consumption. By controlling the shutdown of compressors not involved in hydrogen compression, the compression control system reduces compressor uptime, lowers maintenance frequency and costs, reduces cooling requirements (see the cooler below), and saves on cooling water or cooling energy costs.

[0065] It should be noted that in this embodiment, there may be overlap between different optional pathways. For example, each optional pathway may include a compressor located at the end of the compressor unit (a compressor for communication with the methanol synthesis unit).

[0066] In this structure, the compression control system controls the flow of hydrogen along one of the optional paths by controlling the initial pressure. During the flow, the hydrogen will not flow through the compressor that does not participate in the hydrogen compression, thus reducing the pressure loss during the hydrogen flow. In addition, in this structure, different optional paths can share a compressor. For example, all optional paths can share a compressor located at the end of the compressor group, thereby saving the cost of a multi-stage compression system.

[0067] Specifically, along the direction from the electrolysis hydrogen production unit to the methanol synthesis unit, the compressor unit may include a first compressor 11, a second compressor 21 and a third compressor 31 connected in series via a connecting pipeline, and the outlet of the third compressor 31 is used to connect to the methanol synthesis unit via a connecting pipeline.

[0068] The outlet of the hydrogen buffer tank 02 can be connected in parallel to a first connecting pipe section, a second connecting pipe section, and a third connecting pipe section. The other end of the first connecting pipe section can be connected to the inlet of the first compressor 11, so that the first connecting pipe section and the first compressor 11, the second compressor 21, and the third compressor 31 connected in series downstream of the first connecting pipe section form a first optional path. The other end of the second connecting pipe section can be connected to the inlet of the second compressor 21, so that the second connecting pipe section and the second compressor 21 and the third compressor 31 connected in series downstream of the second connecting pipe section form a second optional path. The other end of the third connecting pipe section can be connected in series to the inlet of the third compressor 31, so that the third connecting pipe section and the third compressor 31 connected downstream of the third connecting pipe section form a third optional path.

[0069] A first shut-off valve 13 is provided on the first connecting pipe section, a second shut-off valve 23 is provided on the second connecting pipe section, and a third shut-off valve 32 is provided on the third connecting pipe section. The compressor unit may also include an intermediate pipe section. Both the second and third connecting pipe sections can be connected to the outlet end of the hydrogen buffer tank 02 via the intermediate pipe section. The intermediate pipe section may be equipped with a second-to-third connecting pipe section shut-off valve 05. After the second-to-third connecting pipe section shut-off valve 05 is closed...

[0070] The second and third connecting pipe sections are closed.

[0071] The multi-stage compression system may further include a compression ratio adjustment mechanism. This mechanism can communicate with the compression control system and all compressors in the compressor unit. The compression control system controls the compression ratio adjustment mechanism based on the number of compressors in the selected active paths and the initial pressure, thereby adjusting the compression ratio of each compressor in the selected active paths. In this case, the compression ratio of each compressor is adjustable, facilitating the stabilization of the compressor unit's outlet pressure and ensuring that the output pressure of the multi-stage compression system in this application is stably maintained at the target pressure.

[0072] Specifically, the compression ratio adjustment mechanism may include multiple frequency converters, the number of which may be the same as the number of compressors, and each converter is communicatively connected to the compressor's drive motor (e.g., via signal lines or wireless connections). The compression control system can adjust the speed of the drive motor by controlling the frequency converters, thereby adjusting the compression ratio of the corresponding compressor. The compressor's drive motor is equipped with a speed sensor, which is communicatively connected to the compression control system, allowing the system to determine the drive motor's speed and thus the compressor's compression ratio.

[0073] The compressor unit may also include a separator for gas-liquid separation. Along the gas flow direction, a separator is located upstream of each compressor in the compressor unit, allowing hydrogen to undergo gas-liquid separation before entering the compressor. Each separator may be equipped with a drain assembly, which is communicatively connected to the compression control system. The compression control system controls the opening and closing of the drain assembly connected to each separator based on the liquid level in each separator.

[0074] Each separator can be equipped with a safety valve, and the outlets of all the safety valves of the separators can be connected in parallel to the safety valve outlet manifold 60.

[0075] Specifically, the drainage assembly may include a drainage pipe, a local level gauge, a remote level gauge, and a level regulating valve. The drainage pipe may be connected to the outlet of the separator. Both the local and remote level gauges are located in the separator and are used to detect the liquid level inside the separator. The remote level gauge and the level regulating valve are communicatively connected to the compression control system to form a regulating loop. When the remote level gauge detects that the liquid level inside the separator is higher than the preset liquid level, the compression control system controls the level regulating valve to open, and the liquid inside the separator is discharged through the drainage pipe. When the remote level gauge detects that the liquid level inside the separator is lower than the preset liquid level, the compression control system controls the level regulating valve to close, so that the liquid level in the separator is maintained at or below the preset liquid level.

[0076] All drain pipes can be connected in parallel to the main drain pipe 50, and draining can be carried out through the main drain pipe 50.

[0077] Local level gauges are also used to detect the liquid level inside the separator. They can be used for comparative monitoring of remote level gauges. That is, by comparing the liquid level detected by the local level gauge with the liquid level detected by the remote level gauge, the accuracy of the remote level gauge can be determined. If the liquid levels detected by the local level gauge and the remote level gauge are different, the staff can check, repair or replace the local level gauge and the remote level gauge.

[0078] Specifically, in this embodiment, the number of compressors can be three, and therefore the number of separators can also be three, namely a first separator 10, a second separator 20, and a third separator 30. The first separator 10 is connected to the inlet end of the compressor unit and upstream of the first compressor 11. The first separator 10 may be equipped with a first drain assembly, which includes a first drain pipe, a first local level gauge 18, a first remote level gauge 19, and a first level regulating valve 101. The second separator 20 is connected between the first compressor 11 and the second compressor 21. Located upstream of the second compressor 21, the second separator 20 may be equipped with a second drain assembly, which may include a second drain pipe, a second local level gauge 28, a second remote level gauge 29, and a second level regulating valve 201. The third separator 30 connects the second compressor 21 and the third compressor 31, located upstream of the third compressor 31. The third separator 30 may be equipped with a third drain assembly, which may include a third drain pipe, a third local level gauge 37, a third remote level gauge 38, and a third level regulating valve 39. The drain assemblies of each separator have the same structure and the same connection relationships with other components in the multi-stage compression system, which will not be described further here.

[0079] The compressor unit may also include a cooler, which can be installed between any two adjacent compressors in the compressor unit. In this case, in two adjacent compressors along the airflow direction, after the hydrogen is compressed by the upstream compressor, it first flows into the cooler, and after being cooled by the cooler, it flows into the downstream compressor. This prevents the compressed hydrogen from directly entering the downstream compressor at a high temperature, which could damage the compressor.

[0080] Specifically, in this embodiment of the application, there can be three compressors and two coolers, namely a first cooler 12 and a second cooler 22. The first cooler 12 can be connected between the first compressor 11 and the second compressor 21, and the second cooler 22 can be connected between the second compressor 21 and the third compressor 31.

[0081] Of course, the compressor unit in this application embodiment may include both a separator and a cooler. In this way, when there are three compressors, the compressor unit may include a first separator 10, a first compressor 11, a first cooler 12, a second separator 20, a second compressor 21, a second cooler 22, a third separator 30, and a third compressor 31 connected in series along the airflow direction. The outlet of the third compressor 31 may be connected to the inlet and outlet heat exchangers of the methanol synthesis unit.

[0082] Multistage compression systems may also include alarm elements that can communicate with the compression control system, which monitors the status of each compressor in the compressor unit.

[0083] In the event of a compressor failure in the compressor unit involved in hydrogen compression, the compression control system controls all compressors in the compressor unit to stop operating and controls the pipeline between the compressor unit inlet and the outlet of the hydrogen buffer tank 02 to be shut off. The compression control system can also control the alarm element to issue a fault alarm signal to notify the staff to carry out maintenance.

[0084] Optionally, the pipeline between the compressor unit inlet and the outlet of the hydrogen buffer tank 02 can be equipped with a hydrogen buffer tank outlet shut-off valve 04. The hydrogen buffer tank outlet shut-off valve 04 is communicatively connected to the compression control system. The compression control system can shut off the pipeline between the compressor unit inlet and the hydrogen buffer tank 02 outlet by controlling the hydrogen buffer tank outlet shut-off valve 04 to cut off the pipeline.

[0085] In the event of a compressor failure in the compressor unit that is not involved in hydrogen compression, the compression control system will control the alarm element to issue an alarm signal to notify personnel to carry out maintenance.

[0086] Optionally, the alarm element can be a buzzer, which emits an alarm signal by beeping. The alarm element can also be an indicator light, which emits an alarm signal by illuminating or flashing. The multi-stage compression system can also include a control panel, which is communicatively connected to the compression control system to display relevant information about the multi-stage compression system. When the compression control system detects a compressor malfunction, it controls the control panel to display the corresponding fault signal, enabling staff to handle the situation promptly.

[0087] The compressor's status includes running, stopped, and fault states. The compressor's drive motor has built-in running and fault contacts, which are communicated to the DI input module of the compression control system via signal lines. When the drive motor is running, the running contact closes, and a signal is transmitted to the compression control system, indicating that the drive motor is running. When the drive motor stops, the running contact opens, and a signal is transmitted to the compression control system, indicating that the drive motor has stopped. When the drive motor fault contact closes, the compression control system receives a fault signal and takes corresponding measures according to the fault type, such as automatic shutdown, issuing a fault alarm, and notifying the operator through the control panel for handling.

[0088] In this embodiment, each compressor inlet is equipped with a pressure transmitter, a temperature transmitter, and a flow meter, and each optional passage inlet is equipped with a flow regulating valve. Each pressure transmitter is used to detect the hydrogen pressure entering the compressor, each temperature transmitter is used to detect the hydrogen temperature entering the compressor, and each flow meter is used to detect the hydrogen flow rate entering the compressor. All pressure transmitters, all temperature transmitters, all flow meters, and all flow regulating valves are communicatively connected to the compression control system. When the compression control system detects abnormal pressure or temperature entering the compressor, it can control all compressors in the compressor unit to shut down and control the hydrogen buffer tank outlet shut-off valve 04 to close. The compression control system is also used to control the opening degree of the flow regulating valve to regulate the hydrogen flow rate entering the optional passage.

[0089] The embodiments of this application may include three compressors. The inlet end of the first compressor 11 may be provided with a first pressure transmitter 14, a first temperature transmitter 15, and a first flow meter 16. The inlet end of the second compressor 21 may be provided with a second pressure transmitter 24, a second temperature transmitter 25, and a second flow meter 26. The inlet end of the third compressor 31 may be provided with a third pressure transmitter 33, a third temperature transmitter 34, and a third flow meter 35.

[0090] The embodiments of this application may include three optional passages. The inlet end of the first optional passage may be provided with a first flow regulating valve 17, that is, the first connecting pipe section may be provided with a first flow regulating valve 17; the inlet end of the second optional passage may be provided with a second flow regulating valve 27, that is, the second connecting pipe section may be provided with a second flow regulating valve 27; and the inlet end of the third optional passage may be provided with a third flow regulating valve 36, that is, the third connecting pipe section may be provided with a third flow regulating valve 36.

[0091] This application embodiment may also include an outlet thermometer 06, an end pressure detector 07, and a compressor unit outlet shut-off valve 08 installed on the pipe section at the outlet of the third compressor 31 (i.e., the compressor unit outlet end). The outlet thermometer 06 is used to detect the outlet temperature of the compressor unit, the end pressure detector 07 is used to detect the outlet pressure of the compressor unit, and the compressor unit outlet shut-off valve 08 is used to control the opening and closing of the pipeline between the compressor unit outlet end and the methanol synthesis unit.

[0092] The outlet thermometer 06, the terminal pressure detector 07, and the compressor unit outlet shut-off valve 08 are all connected to the compression control system. When the outlet thermometer 06 detects that the hydrogen temperature at the compressor unit outlet is greater than the preset temperature, and / or when the pressure difference between the hydrogen pressure at the compressor unit outlet and the target pressure detected by the terminal pressure detector 07 is greater than the preset pressure difference (the preset pressure difference can be greater than zero or equal to zero), the compression control system controls the compressor unit outlet shut-off valve 08 to close, or controls all compressors in the compressor unit to stop.

[0093] As can be seen from the above, the compression control system of this application embodiment can control the number of compressors participating in hydrogen compression in the compressor unit according to the initial pressure of hydrogen at the inlet of the compressor unit.

[0094] Specifically, the compression control system can collect the pressure P of the hydrogen buffer tank 02 in real time (i.e., the initial pressure of the hydrogen produced by the electrolytic hydrogen production component) to carry out subsequent multi-stage dynamic control steps. The multi-stage dynamic control starts the compressors at each stage based on the interval pressure. In this dynamic control, the outlet shut-off valve 04 of the hydrogen buffer tank remains open.

[0095] The pressure range in this embodiment can be three control ranges: P0≤P<P1, P1≤P<P2, and P2≤P≤P3. It should be noted that P3 is the hydrogen production pressure of the electrolyzer 01 when the renewable energy power generation device is operating at full load, and it is also the pressure of the hydrogen buffer tank 02.

[0096] When P0≤P<P1, the first compressor 11, the second compressor 21 and the third compressor 31 are started simultaneously, so that all compressors are in working condition. At this time, the first shut-off valve 13 is opened and the second three-way connecting pipe section shut-off valve 05, the second shut-off valve 23 and the third shut-off valve 32 are closed. That is to say, when the hydrogen pressure in the hydrogen buffer tank 02 is within the range of P0≤P<P1, the first optional passage is opened and the hydrogen flows along the first optional passage.

[0097] The pressure, temperature, and flow rate data at the inlet of the first separator 10 are monitored. A flow rate value of F1 is set to ensure stable operation of the first selectable path. The opening of the first flow regulating valve 17 is adjusted by the compression control system to stabilize the hydrogen flow rate at the F1 value. After liquid removal by the first separator 10, the hydrogen enters the first compressor 11 for compression. The target outlet pressure of the first compressor 11 is set to P1 + 0.01 MPa. This is used to control the frequency converter of the first compressor 11, adjusting the speed of the drive motor and thus the compression ratio. After cooling by the first cooler 12, the hydrogen from the outlet of the first compressor 11 enters the second separator 20. The pressure, temperature, and flow rate data at the inlet of the second compressor 21 are monitored. After liquid removal by the second separator 20, the hydrogen enters the second compressor 21 for compression. The target outlet pressure of the second compressor 21 is set to P1 * 3 MPa. This is used to control the frequency converter of the second compressor 21, adjusting the speed of the drive motor and thus the compression ratio. The hydrogen gas exiting the second compressor 21 is cooled by the second cooler 22 and then enters the third separator 30. The pressure, temperature, and flow data at the inlet of the third compressor 31 are monitored. After the hydrogen gas is separated and liquid is removed by the third separator 30, it enters the third compressor 31 for compression. The target outlet pressure of the third compressor 31 is set to Ps MPa (the target pressure for hydrogen gas entering the methanol synthesis system). This is used to control the frequency converter of the third compressor 31, adjust the speed of the drive motor of the third compressor 31, and adjust the compression ratio of the third compressor 31. At the same time, the outlet temperature and pressure of the third compressor 31 (i.e., the temperature and pressure at the outlet of the compressor unit) are monitored, and the compressor unit outlet shut-off valve 08 is opened to send the hydrogen gas with the target pressure to the inlet and outlet heat exchangers of the methanol synthesis unit.

[0098] When P1≤P<P2, the second compressor 21 and the third compressor 31 are started and put into operation, while the first compressor 11 is shut down. At this time, the first shut-off valve 13 is closed, the second three-way connecting pipe section shut-off valve 05 and the second shut-off valve 23 are opened, and the third shut-off valve 32 is closed. That is to say, when the initial pressure is within the pressure range of P1≤P<P2, the second optional passage is opened, and hydrogen flows along the second optional passage.

[0099] The pressure, temperature, and flow rate data at the inlet of the second compressor 21 are monitored. A flow rate value of F2 is set to ensure stable operation of the second optional pathway. The opening of the second flow regulating valve 27 is adjusted by the compression control system to stabilize the hydrogen flow rate at the F2 value. After liquid removal by the second separator 20, the hydrogen enters the second compressor 21 for compression. The target pressure at the outlet of the second compressor 21 is set to P2 + 0.03 MPa. This pressure is used to control the frequency converter of the second compressor 21, adjusting the speed of the drive motor and thus the compression ratio. After being cooled by the second cooler 22, the hydrogen exiting the second compressor 21 enters the third separator 30. The pressure, temperature, and flow rate data at the inlet of the third compressor 31 are monitored. After the hydrogen is separated and the liquid is removed by the third separator 30, it enters the third compressor 31 for compression. The target outlet pressure of the third compressor 31 is set to Ps MPa (the target pressure value of hydrogen entering the methanol synthesis unit). This controls the frequency converter of the third compressor 31, adjusts the speed of the drive motor of the third compressor 31, and adjusts the compression ratio of the third compressor 31. At the same time, the outlet temperature and pressure of the third compressor 31 (i.e., the temperature and pressure at the outlet end of the compressor unit) are detected, and the compressor unit outlet shut-off valve 08 is opened to send the hydrogen with the target pressure to the inlet and outlet heat exchangers of the methanol synthesis unit.

[0100] When P2≤P≤P3, the third compressor 31 is started and the first compressor 11 and the second compressor 21 are shut down. At this time, the first shut-off valve 13 and the second shut-off valve 23 are closed, and the second three-way connecting pipe section shut-off valve 05 and the third shut-off valve 32 are opened. That is to say, the third optional passage is opened, and hydrogen flows along the third optional passage.

[0101] The pressure, temperature, and flow data at the inlet of the third compressor 31 are monitored. A flow rate of F3 is set to ensure stable operation of the third optional pathway. The opening of the third flow regulating valve 36 is adjusted by the compression control system to stabilize the hydrogen flow rate at F3. After liquid removal by the third separator 30, the hydrogen enters the third compressor 31 for compression. The target outlet pressure of the third compressor 31 is set to Ps MPa (target pressure for hydrogen entering the methanol synthesis system). This controls the frequency converter of the third compressor 31, adjusting the speed of the drive motor and the compression ratio. Simultaneously, the outlet temperature and pressure of the compressor unit are monitored, and the compressor unit outlet shut-off valve 08 is opened to deliver hydrogen at the target pressure to the inlet and outlet heat exchangers of the methanol synthesis unit.

[0102] Specifically, when renewable energy is generating electricity at full capacity, the hydrogen production pressure from water electrolysis can be 3 MPa. Therefore, the operating pressure of the hydrogen buffer tank 02 can be designed to be 3 MPa. When wind and solar resources are insufficient for a long period, the hydrogen production capacity will decrease significantly, causing the pressure of the hydrogen buffer tank 02 to gradually decrease. The target pressure Ps for hydrogen entering the methanol synthesis unit and the target pressure Ps at the outlet of the third compressor 31 can be designed to be 8 MPa. The pressure range for simultaneous operation of the three compressors can be set to 0.3 MPa ≤ P < 0.89 MPa, with the target outlet pressure of the first compressor 11 being 0.9 MPa and the target outlet pressure of the second compressor 21 being 2.7 MPa. The pressure range for simultaneous operation of the second compressor 21 and the third compressor 31 can be set to 0.89 ≤ P < 2.67 MPa, with the target outlet pressure of the second compressor 21 being 2.7 MPa. The pressure range for operating only the third compressor 31 can be set to 2.67 ≤ P ≤ 3 MPa. The target pressure Ps for hydrogen entering the methanol synthesis system can be achieved through single-stage compression.

[0103] Of course, the values ​​of each pressure range can be adjusted according to the actual situation and are not limited to the values ​​of the pressure ranges mentioned above.

[0104] The compression control system of this application embodiment adopts a modular design and uses fully automatic closed-loop PID control. The compression control system includes a CPU module, an A / D module, a D / A module, and DI and DO modules. Each component, such as flow meters and remote level gauges, that needs to achieve automatic closed-loop PID control outputs analog signals to the PLC's A / D module. The regulating valves are controlled by analog signals output from the PLC's D / A module. The on / off state (open or closed) of each shut-off valve is input as a digital signal to the PLC's DI module. The control command (open or close) of the shut-off valve by the CPU module is sent as a digital output signal from the CPU module to the shut-off valve actuator through the DO module.

[0105] Meanwhile, the compression control system can communicate with the DCS system of the methanol production line via the RS-485 communication protocol, and the DCS system of the methanol production line can monitor the multi-stage compression system.

[0106] The multi-stage compression system may include a renewable energy power generation unit and a backup power supply. Both the renewable energy power generation unit and the backup power supply are energized and connected to the electrolyzer 01 of the hydrogen electrolysis assembly, thereby supplying power to the electrolyzer 01.

[0107] A renewable energy power generation device is a device that can generate electricity using renewable energy sources such as solar energy and wind energy. Optionally, a renewable energy power generation device may include a wind power generation device 40, a photovoltaic device 41, or both a wind power generation device 40 and a photovoltaic device 41. Of course, it may also include other devices that generate electricity using renewable energy sources.

[0108] Hydrogen produced by electrolyzing water using renewable energy is called "green" hydrogen. Green hydrogen is a raw material for producing green methanol, a carbon-neutral cornerstone energy source made by coupling green carbon dioxide and green hydrogen. The production process has negative carbon emissions, and the combustion process emits only water and carbon dioxide. Net emissions are zero, reducing greenhouse gas emissions and contributing to the achievement of global energy conservation and emission reduction goals.

[0109] Hydrogen is produced by electrolyzing water using renewable energy power generation devices. However, when renewable energy is insufficient for a long period, such as during consecutive cloudy or windless days, the hydrogen production capacity drops significantly. This results in the hydrogen buffer tank 02 not being able to be replenished in time. Moreover, the hydrogen buffer tank 02 has a limited capacity, which restricts its buffering ability and makes it unable to cope with large pressure fluctuations for a long time. Therefore, the backup power source can be the power grid, a battery, or other devices that can provide relatively stable power to the electrolyzer 01.

[0110] In the embodiments of this application, the multi-stage compression system may further include a predictive control system.

[0111] The predictive control system is used to acquire forecast information on renewable energy sources and to predict the availability of renewable energy sources within a preset timeframe based on this forecast information. The renewable energy sources in this application can be solar and wind energy, and the forecast information for renewable energy sources can be obtained through weather forecasts.

[0112] Within a predetermined timeframe, if the availability of renewable energy is lower than the predetermined availability, the predictive control system or the compression control system will control the backup power supply to power electrolyzer 01. It should be noted that the predetermined timeframe refers to a period of time following the current prediction time of the predictive control system, such as two hours, three hours, one day, three days, etc.

[0113] In the future, within a preset time period, if the availability of renewable energy is greater than or equal to the preset availability, the predictive control system or the compression control system controls the renewable energy power generation device to supply power to the electrolyzer 01, and controls the backup power supply to stop supplying power to the electrolyzer 01, thereby reducing dependence on fossil fuels and reducing greenhouse gas emissions.

[0114] In this situation, the predictive control system can predict the power supply trend of renewable energy power generation devices. When renewable energy is insufficient for a long period of time, it can automatically switch to backup power supply to maintain the output of hydrogen production by water electrolysis, ensure uninterrupted hydrogen production, and reduce the downtime frequency of methanol production lines.

[0115] It should be noted that when the availability of renewable energy is equal to the preset availability, the outlet pressure of the compressor unit can reach the target pressure when the renewable energy power generation unit supplies power to the electrolysis hydrogen production unit and all compressors in the compressor unit participate in hydrogen compression. However, when the availability of renewable energy is lower than the preset availability, even if all compressors in the compressor unit participate in hydrogen compression, the outlet pressure of the compressor unit cannot reach the target pressure.

[0116] In the above text, when it is predicted whether the availability of renewable energy within a preset time period will be lower than the preset availability, there are different power supply methods (i.e., whether to use renewable energy power generation devices or backup power to power electrolyzer 01). Optionally, in the embodiments of this application, the power supply method can be controlled by a predictive control system or by a compression control system.

[0117] Specifically, when using a predictive control system to control the power supply, the predictive controller of the predictive control system can control the power supply to or from the renewable energy power generation device and the electrolyzer 01, and the power supply to or from the backup power supply and the electrolyzer 01, based on the prediction results (whether the availability of renewable energy within a preset time period is lower than the preset availability), thereby controlling the renewable energy power generation device and / or the backup power supply to supply power to the electrolyzer 01.

[0118] Specifically, when using the compression control system to control the power supply mode, the predictive controller of the predictive control system can communicate with the compression control system. The predictive controller can transmit the prediction results to the compression control system. The compression control system can control the power supply to or from the renewable energy power generation device and the electrolytic cell 01, and the power supply to or from the backup power supply and the electrolytic cell 01, based on the prediction results, thereby controlling the renewable energy power generation device and / or the backup power supply to supply power to the electrolytic cell 01.

[0119] Renewable energy power generation devices and backup power supplies are electrically connected to the electrolysis hydrogen production components, and there are various connection methods.

[0120] In one optional embodiment, the power output terminal and backup power supply of the renewable energy power generation device can be electrically connected to the electrolysis hydrogen production component through a dual power automatic transfer switch. The power output terminal of the renewable energy power generation device and the transmission line of the backup power supply (grid) can be electrically connected to the two power input ports of the dual power automatic transfer switch, respectively. The output port of the dual power automatic transfer switch can be electrically connected to the electrolysis cell 01.

[0121] Under this structure, the predictive control system or the compression control system can control the position of the dual power automatic switching switch to energize one of the renewable energy power generation device or the backup power supply to the electrolyzer 01 and de-energize the other to the electrolyzer 01. In other words, only one of the renewable energy power generation device and the backup power supply can supply power to the electrolyzer 01 at the same time.

[0122] In another optional embodiment, the power output terminal of the renewable energy power generation device and the transmission line of the backup power supply can be connected in parallel to the electrolysis hydrogen production component. In this structure, the predictive control system or the compression control system can control the power supply or power cut-off of the renewable energy power generation device and the electrolyzer 01 by controlling the opening and closing of the switches on the connection branch of the renewable energy power generation device and the electrolyzer 01, and control the power supply or power cut-off of the backup power supply and the electrolyzer 01 by controlling the opening and closing of the switches on the connection branch of the backup power supply and the electrolyzer 01.

[0123] In this embodiment, the switches on the connecting branch of the renewable energy power generation device and the electrolyzer 01, and the switches on the connecting branch of the backup power supply and the electrolyzer 01 can be closed simultaneously. Therefore, the two power supplies can supply power to the electrolysis hydrogen production component at the same time. Thus, in the future, if the availability of renewable energy is lower than the preset availability within a preset time period, the predictive control system or the compression control system can control the backup power supply to supply power to the electrolysis hydrogen production component, or it can control the renewable energy power generation device and the backup power supply to supply power to the electrolysis hydrogen production component at the same time.

[0124] The predictive control system includes a data processing module and a predictive controller. The data processing module is used to collect future weather forecast information, and the predictive controller is used to determine, based on the future weather forecast information, whether the availability of renewable energy will be lower than the preset availability within a preset time period.

[0125] There are several ways to determine whether the availability of renewable energy is lower than the preset availability.

[0126] In one optional embodiment, the forecast controller is used to predict the predicted pressure of hydrogen in hydrogen buffer tank 02 within a preset time period based on future weather forecast information. If the predicted pressure is less than the preset pressure, the renewable energy availability is lower than the preset availability; if the predicted pressure is greater than or equal to the preset pressure, the renewable energy availability is greater than or equal to the preset availability.

[0127] Optionally, the preset pressure can be set to P0, which can be 0.3 MPa.

[0128] It should be noted that since the predicted pressure of hydrogen in the hydrogen buffer tank 02 is continuous data, when determining the availability of renewable energy, if the predicted pressure is lower than the preset pressure within a preset future time period, the renewable energy availability is determined to be lower than the preset availability. Alternatively, if the predicted pressure remains lower than the preset pressure within a preset future time period, the renewable energy availability is determined to be lower than the preset availability. Conversely, if the predicted pressure remains equal to or greater than the preset pressure within a preset future time period, the renewable energy availability is determined to be equal to or greater than the preset availability. Of course, these determination rules can be adjusted according to specific circumstances.

[0129] In another optional embodiment, the forecast controller is used to forecast the predicted power generation of the renewable energy power generation device within a preset time period based on future weather forecast information. If the predicted power generation is less than the preset power generation, the renewable energy availability is lower than the preset availability; if the predicted power generation is greater than or equal to the preset power generation, the renewable energy availability is greater than or equal to the preset availability.

[0130] Similarly, since the predicted power generation of renewable energy power generation devices is continuous data, when determining renewable energy availability, if there is a situation where the predicted power generation is less than the preset power generation within a preset future period, the renewable energy availability is determined to be lower than the preset availability. Alternatively, if the predicted power generation is consistently less than the preset power generation within a preset future period, the renewable energy availability is determined to be lower than the preset availability. Conversely, if the predicted power generation is consistently equal to or greater than the preset power generation within a preset future period, the renewable energy availability is determined to be equal to or greater than the preset availability. Of course, these determination rules can be adjusted according to specific circumstances.

[0131] Of course, in this embodiment of the application, the availability of renewable energy can be determined to be lower than the preset availability by simultaneously predicting the predicted power generation of the renewable energy power generation device within a preset time period and the predicted pressure of hydrogen in the hydrogen buffer tank 02 within a preset time period.

[0132] When the initial pressure is greater than or equal to the preset pressure and continues to decrease, the predictive controller of the predictive control system is activated to begin predicting the availability of renewable energy within a preset time period in the future.

[0133] The predictive control system can communicate with the compression control system. The initial pressure detector 03 can also communicate with the compression control system. When the compression control system receives a signal that the initial pressure is greater than or equal to the preset pressure (P0) and continues to decrease, the compression control system controls the data processing module and predictive controller of the predictive control system to start predicting the availability of renewable energy within a preset time period.

[0134] When the initial pressure is greater than or equal to the preset pressure and is not in a state of continuous decrease, the predictive control system stops predicting the availability of renewable energy within a preset time period (at this time, the predictive control system can be turned off), and controls the renewable energy power generation device to supply power to the electrolyzer, and controls the backup power supply to stop supplying power to electrolyzer 01.

[0135] When the initial pressure is lower than the preset pressure, the renewable energy power generation device is controlled to supply power to the electrolyzer, and the backup power supply is controlled to stop supplying power to the electrolyzer.

[0136] As mentioned above, the renewable energy power generation device and the backup power supply can be connected to the compression control system so that the compression control system can control the power supply to or from the electrolytic cell 01 of the renewable energy source and the backup power supply to or from the electrolytic cell 01.

[0137] In this case, the multi-stage compression system in this application embodiment can preferentially use renewable energy power generation devices to power the electrolyzer 01, and when the multi-stage compression system is operating stably and the future availability of renewable energy is predicted to be insufficient, switch the backup power supply to power the electrolyzer 01 to ensure the stable preparation of hydrogen at the target pressure during the operation of the multi-stage compression system.

[0138] Of course, in other alternative embodiments, the predictive control system can be started when the multi-stage compression system is in the startup state, that is, the predictive control system starts when the multi-stage compression system starts.

[0139] To enable the predictive function of the predictive controller, the predictive controller may include a predictive model. The predictive model can predict the predicted pressure of hydrogen in the hydrogen buffer tank 02 within a preset time period based on future weather forecast information, and predict the predicted power generation of the renewable energy power generation device within a preset time period.

[0140] Optionally, during the establishment of the prediction model, the data processing module can collect historical weather data, historical power generation data of renewable energy power generation devices, and historical pressure data of the initial pressure of hydrogen produced by the electrolysis hydrogen production component. Then, using historical weather data (such as temperature, wind speed, and weather conditions) as input and historical power generation and historical initial pressure data as output, the module uses big data analysis technology (such as neural networks) to analyze the correlation between historical weather data, historical power generation, and historical initial pressure data. This allows for the establishment of a power generation and pressure prediction model that takes weather forecast information as input and predicts power generation and pressure as output. The model is then trained to obtain the prediction model.

[0141] Predictive control systems can acquire historical weather data and weather forecast information in various ways. Optionally, the data processing module can obtain weather data via network or API in JSON or XML format. The module then parses the acquired data, extracts relevant weather forecast information (such as temperature, wind speed, and whether it's sunny or rainy), and converts this data into signal formats that the predictive controller can process. For example, the data processing module converts the parsed continuous data (e.g., wind speed, temperature) into analog signals (e.g., 0-10V or 4-20mA) and connects it to the predictive controller via analog input (AI) terminals; it converts the parsed switch data (sunny, rainy) into digital signals (e.g., 0 / 1) and connects it to the predictive controller via digital input (DI) terminals.

[0142] When the data processing module acquires historical weather data and future weather forecast information via the network, the predictive control system may include a connection module. This connection module connects to the network and then to a weather forecast information server to obtain future weather forecast information and historical weather data. When the data processing module acquires historical weather data and future weather forecast information via an API, the predictive control system may include a weather data acquisition unit. This weather data acquisition unit has a weather forecast API interface to obtain weather forecast information.

[0143] It should be noted that historical weather data can be obtained in the present by acquiring historical data, or it can be obtained from weather forecast information that has been acquired and retained in the past.

[0144] In order to obtain historical pressure data and historical power generation data, the initial pressure detector 03 can be connected to the data processing module so that the data processing module can obtain the historical pressure data of the initial pressure. The renewable power generation device can have a power generation detection module, which can be connected to the data processing module so that the data processing module can obtain the historical power generation data of the renewable energy power generation device.

[0145] In order to switch between the two power sources after obtaining the prediction results, the predictive control system can communicate with the dual power source switching switch to control the automatic switching action of the dual power source and realize the switching between the two power sources; or, when the backup power source and the renewable energy power generation device are connected in parallel with the electrolyzer 01, the switch of the line connecting the backup power source and the electrolyzer 01, the switch of the line connecting the renewable energy power generation device and the electrolyzer 01, and the predictive control system can communicate with the predictive control system to control the switching action on the two parallel lines and realize the switching between the two power sources.

[0146] Based on the aforementioned multi-stage compression system, this application also provides a methanol production line, which includes the aforementioned multi-stage compression system. Since this methanol production line has the aforementioned multi-stage compression system, the beneficial effects brought by the multi-stage compression system are described above and will not be repeated here.

[0147] With the increasing severity of global greenhouse gas emissions, the development of the global economy, and population growth, energy demand will continue to grow, making the research and application of green energy increasingly important.

[0148] Green methanol uses renewable raw materials and energy. It can be produced from biomass, waste, and solar energy, reducing reliance on traditional non-renewable energy sources like oil and natural gas, and effectively decreasing greenhouse gas emissions. Therefore, green methanol has broad application prospects. Besides its use in zero-carbon ocean shipping, it can be used to produce downstream chemicals such as zero-carbon olefins and zero-carbon aromatics, driving the chemical industry towards zero-carbon transformation and upgrading. Simultaneously, it can also promote the development and utilization of renewable energy, contributing to the achievement of global emission reduction targets.

[0149] In the methanol production line of this application, the electricity for hydrogen production largely comes from renewable energy power generation devices. Therefore, the hydrogen produced most of the time is green hydrogen, and green methanol can be obtained through the production of green hydrogen, which helps to reduce greenhouse gas emissions.

[0150] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0151] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0152] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0153] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0154] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0155] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A multi-stage compression system for a methanol production line, characterized in that: include: A compressor unit, wherein the inlet of the compressor unit is connected to the outlet of the hydrogen buffer tank of the electrolytic hydrogen production assembly, and the outlet of the compressor unit is used to communicate with the methanol synthesis device; An initial pressure detector, used to detect the hydrogen pressure in the hydrogen buffer tank, so as to detect the initial pressure of the hydrogen produced by the electrolytic hydrogen production component; A compression control system is communicatively connected with the initial pressure detector and the compressor unit, wherein: The compression control system is used to control the number of compressors in the compressor group participating in hydrogen compression according to the initial pressure, and the number of compressors in the compressor group participating in hydrogen compression is inversely proportional to the initial pressure, so that the compressor group pressurizes different initial pressures to the target pressure.

2. The multi-stage compression system of the methanol production line according to claim 1, characterized in that: The compressor group includes a plurality of compressors connected in series, and also includes a plurality of connecting pipe sections, the first ports of all the connecting pipe sections are connected in parallel to the outlet end of the hydrogen buffer tank, and the second ports of all the connecting pipe sections are connected one by one to the inlet end of each of the compressors, so that the compressor group forms a plurality of parallel optional passages, and the number of compressors in each optional passage is different; Each of the connecting pipe sections is provided with a cut-off valve, and all of the cut-off valves are communicatively connected with the compression control system, wherein: The compression control system is used to control the switch of each of the cut-off valves according to the initial pressure, and to make one of the optional passages conductive and the other optional passages blocked.

3. The multi-stage compression system of the methanol production line according to claim 2, characterized in that: The multi-stage compression system further comprises a compression ratio adjustment mechanism, which is in communication connection with the compression control system and all the compressors in the compressor group, wherein: The compression control system is used to control the compression ratio adjustment mechanism according to the number of compressors in the turned-on optional path and the initial pressure, so as to adjust the compression ratio of each compressor in the turned-on optional path.

4. The multi-stage compression system of the methanol production line according to claim 1, characterized in that: The compressor unit further comprises a separator for gas-liquid separation, wherein the separator is provided upstream of each compressor in the compressor unit along the airflow direction, and each of the separators is provided with a liquid discharge component, and the liquid discharge component is communicatively connected with the compression control system, and the compression control system is used to control the conduction and cutoff of the liquid discharge component connected thereto according to the liquid level of each of the separators; and / or, The compressor unit further comprises a cooler, and the cooler is arranged between any two adjacent compressors in the compressor unit.

5. The multi-stage compression system of the methanol production line according to claim 1, characterized in that: The multi-stage compression system further comprises an alarm element, the alarm element being in communication with the compression control system, the compression control system being used to monitor the status of each compressor in the compressor group, wherein: In the event of a failure of a compressor involved in hydrogen compression in the compressor group, the compression control system controls all compressors of the compressor group to stop running, and controls the communication passage between the compressor group inlet and the outlet of the hydrogen buffer tank to be cut off; In the event of a failure of a compressor in the compressor group that does not participate in hydrogen compression, the compression control system controls the alarm element to send out an alarm signal.

6. The multi-stage compression system of the methanol production line according to claim 1, characterized in that: The multi-stage compression system also includes: A renewable energy power generation device, which can be electrically connected to the electrolyzer of the electrolytic hydrogen production assembly; A backup power supply, which can be electrically connected to the electrolyzer of the electrolysis hydrogen production assembly; A prediction control system, used to obtain forecast information of renewable energy, and to predict the availability of renewable energy within a preset time period in the future based on the forecast information, wherein: During the preset future time period, when the availability of the renewable energy source is lower than the preset availability, the backup power source supplies power to the electrolyzer; During the future preset time period, when the renewable energy availability is greater than or equal to the preset availability, the renewable energy power generation device supplies power to the electrolyzer, and the backup power supply stops supplying power to the electrolyzer.

7. The multi-stage compression system of the methanol production line according to claim 6, characterized in that: The power output end of the renewable energy power generation device and the backup power supply are electrically connected to the electrolyzer via a dual power automatic switching switch, and within the future preset time period, when the availability of the renewable energy is lower than the preset availability, the renewable energy power generation device stops supplying power to the electrolyzer; or, The power output end of the renewable energy power generation device and the backup power supply are connected in parallel to the electrolytic cell. Within the future preset time period, when the availability of the renewable energy is lower than the preset availability, the renewable energy power generation device and the backup power supply supply power to the electrolytic cell.

8. The multi-stage compression system of the methanol production line according to claim 6, characterized in that: The prediction control system includes a data processing module and a prediction controller. The data processing module is used to collect future weather forecast information. The prediction controller is used to predict the predicted pressure of hydrogen in the hydrogen buffer tank within the future preset time period according to the future weather forecast information, and when the predicted pressure is less than the preset pressure, the renewable energy availability is lower than the preset availability, and when the predicted pressure is greater than or equal to the preset pressure, the renewable energy availability is greater than or equal to the preset availability; and / or, The prediction controller is used to predict the predicted power generation of the renewable energy power generation device within the future preset time period based on the future weather forecast information. When the predicted power generation is less than the preset power generation, the renewable energy availability is lower than the preset availability. When the predicted power generation is greater than or equal to the preset power generation, the renewable energy availability is greater than or equal to the preset availability.

9. The multi-stage compression system of the methanol production line according to claim 6, characterized in that: When the initial pressure is greater than or equal to a preset pressure and continues to decrease, the prediction control system predicts the availability of renewable energy within the future preset time period; When the initial pressure is greater than or equal to the preset pressure and is not in a continuously decreasing state, the prediction control system stops predicting the availability of renewable energy within the preset future time period, and the renewable energy power generation device supplies power to the electrolyzer, and the backup power supply stops supplying power to the electrolyzer; When the initial pressure is less than the preset pressure, the renewable energy power generation device supplies power to the electrolytic cell, and the backup power supply stops supplying power to the electrolytic cell.

10. A methanol production line, characterized in that: Comprising a multi-stage compression system as described in any one of claims 1-9.

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