Steam methane reformer and method of controlling the same, and computer readable storage medium

Abstract

The present disclosure relates to a steam methane reformer and a control method thereof, and a computer-readable storage medium. A method for improving start-up stability of a steam methane reformer and optimizing an amount of a used cycle gas, and an apparatus thereof, the method including, based on a start-up of the steam methane reformer, supplying a start-up gas by opening a supply valve of the start-up gas, activating an operation mode of a pressure indicating controller to an automatic mode, and based on an internal pressure of the steam methane reformer reaching a target value when the start-up gas is supplied, controlling a pressure control valve by the pressure indicating controller to match a supply flow rate of the start-up gas with a flow rate of a gas discharged to an outside of the steam methane reformer.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2025-0056537, filed with the Korean Intellectual Property Office on April 29, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to steam methane reformers, and more specifically, to techniques for improving the start-up stability of steam methane reformers and optimizing the amount of circulating gas used. Background Technology

[0004] Facilities that require a continuous hydrogen supply can sometimes produce hydrogen by reforming steam methane. The energy consumption and temperature / pressure variability in such equipment have implications for cost, production quality, and safety.

[0005] Based on existing natural gas availability and infrastructure, natural gas reforming has developed into an advanced and mature process. 95% of hydrogen produced in the United States is produced using natural gas reforming.

[0006] A steam methane reformer (SMR) is equipment used to reform methane, a major component of natural gas that uses steam to produce hydrogen and emits carbon. At this stage, the produced hydrogen is gray hydrogen. If the emitted carbon is captured, stored, or used during hydrogen production, the gray hydrogen becomes blue hydrogen.

[0007] To increase the efficiency of steam methane reformers, it is important to minimize the consumption of gas used during startup and to stabilize the internal pressure of the system at a certain level during initial startup.

[0008] However, because the existing technology only provides the function of opening or closing the valve for supplying starting gas, it cannot effectively control the amount of starting gas used. Summary of the Invention

[0009] This disclosure has been made to address the aforementioned problems in the related art, while maintaining the advantages achieved by the related art without being affected.

[0010] Various aspects of this disclosure provide methods and apparatus for improving the start-up stability of steam methane reformers and optimizing the amount of circulating gas used.

[0011] Various aspects of this disclosure provide a steam methane reformer for adaptively controlling the flow rate of start-up gas based on the internal pressure of the system, thereby improving start-up stability and optimizing the amount of circulating gas used.

[0012] Various aspects of this disclosure provide methods and apparatus for improving the start-up stability of a steam methane reformer and optimizing the amount of circulating gas used to interlock the pressure indicator controller and the flow indicator controller to adaptively control the mode of the flow indicator controller to minimize periods of pressure instability and to minimize the amount of start-up gas discharged to the outside of the steam methane reformer.

[0013] The technical problems to be solved by this disclosure are not limited to those described above, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art from the following description.

[0014] According to various aspects of this disclosure, a method for operating a steam methane reformer may include: supplying start-up gas by opening a start-up gas supply valve based on the start-up of the steam methane reformer; activating the operating mode of a pressure indicator controller to an automatic mode; and controlling a pressure control valve by the pressure indicator controller to match the supply flow rate of the start-up gas with the flow rate of gas discharged to the outside of the steam methane reformer based on the internal pressure of the steam methane reformer reaching a target value when the start-up gas is supplied.

[0015] According to various aspects of this disclosure, the method may further include: switching the operating mode of the flow indicator controller from automatic mode to cascade mode based on the internal pressure reaching a target value, and activating the flow indicator controller setpoint (SP) calculator to determine the SP of the flow indicator controller based on the output (OP) of the pressure indicator controller.

[0016] According to various aspects of this disclosure, a flow indicator controller for regulating the opening of a flow control valve and a pressure indicator controller for regulating the opening of a pressure control valve can be interlocked with each other based on switching to a cascaded mode. The flow indicator controller SP calculator can set SP such that the pressure indicator controller stably maintains its internal pressure.

[0017] According to various aspects of this disclosure, the method may further include: in cascade mode, maintaining the internal pressure at a target value while reducing the supply flow rate of the start-up gas through interlocking.

[0018] According to various aspects of this disclosure, the supply flow rate of the start-up gas can be reduced to a lower limit set by the flow indicator controller. The lower limit can be the flow rate value when the pressure control valve is 50% open in cascade mode.

[0019] According to various aspects of this disclosure, depending on the system specifications, the supply flow rate of the start-up gas in cascade mode can be reduced to the minimum flow rate level that can stably maintain the internal pressure, and can ideally be reduced to 20% of the supply flow rate of the start-up gas in automatic mode.

[0020] According to various aspects of this disclosure, after the internal pressure reaches the target value, a period of internal pressure instability may occur when the supply flow rate of the start-up gas exceeds the gas flow rate discharged to the outside. Based on the internal pressure reaching the target value, the supply flow rate of the start-up gas can be reduced to a level that minimizes the period of instability.

[0021] According to various aspects of this disclosure, depending on the system specifications, the target value can be set to any value in the range of greater than 0 bar and less than 10 bar, and ideally, it can be set to any value in the range of greater than 7 bar and less than 8 bar.

[0022] According to various aspects of this disclosure, the starting gas may include at least one of hydrogen and nitrogen.

[0023] According to various aspects of this disclosure, a steam methane reformer may include: a start-up gas supply valve, which opens upon startup of the steam methane reformer to supply start-up gas to the interior of the steam methane reformer; a pressure indicating controller configured to monitor changes in the internal pressure of the steam methane reformer and control the internal pressure when the start-up gas is supplied; and a pressure control valve that adjusts its opening according to the output (OP) of the pressure indicating controller and discharges the start-up gas to the outside of the steam methane reformer. The pressure indicating controller may be configured to control the pressure control valve based on the internal pressure reaching a predetermined target value, such that the supply flow rate of the start-up gas is the same as the flow rate of the discharged gas.

[0024] According to various aspects of this disclosure, the operating mode of the pressure indicator controller can be activated to automatic mode when the steam methane reformer is started.

[0025] According to various aspects of this disclosure, the steam methane reformer may further include: a flow control valve for regulating the supply flow rate of start-up gas, a flow indicator controller for controlling the opening degree of the flow control valve, and a flow indicator controller SP calculator for determining the set point (SP) of the flow indicator controller based on the OP of the pressure indicator controller. Based on the internal pressure reaching a target value, the operating mode of the flow indicator controller can be switched from automatic mode to cascaded mode to activate the flow indicator controller SP calculator.

[0026] According to various aspects of this disclosure, the flow indicator controller and the pressure indicator controller can be interlocked with each other based on switching to cascade mode. The flow indicator controller SP calculator can set SP so that the pressure indicator controller stably maintains the internal pressure.

[0027] According to various aspects of this disclosure, in cascade mode, the pressure indicator controller can be configured to control the flow indicator controller to maintain the internal pressure at a target value while reducing the supply flow rate of the start-up gas through interlocking.

[0028] According to various aspects of this disclosure, the supply flow rate of the start-up gas can be reduced to a lower limit set by the flow indicator controller. The lower limit can be the flow rate value when the pressure control valve is 50% open in cascade mode.

[0029] According to various aspects of this disclosure, depending on the system specifications, the supply flow rate of the start-up gas in cascade mode can be reduced to the minimum flow rate level that can stably maintain the internal pressure, and can ideally be reduced to 20% of the supply flow rate of the start-up gas in automatic mode.

[0030] According to various aspects of this disclosure, after the internal pressure reaches the target value, a period of internal pressure instability may occur when the supply flow rate of the start-up gas exceeds the gas flow rate discharged to the outside. Based on the internal pressure reaching the target value, the supply flow rate of the start-up gas can be reduced to a level that minimizes the period of instability.

[0031] According to various aspects of this disclosure, depending on the system specifications, the target value can be set to any value in the range of greater than 0 bar and 10 bar, and ideally can be set to any value in the range of greater than 7 bar and 8 bar.

[0032] According to various aspects of this disclosure, the starting gas may include at least one of hydrogen and nitrogen. Attached Figure Description

[0033] The above and other objects, features, and advantages of this disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings:

[0034] Figure 1 It is a diagram used to illustrate the configuration and operating principle of a steam methane reformer according to an exemplary embodiment of the present disclosure;

[0035] Figure 2 It is used to describe Figure 1 A flowchart of the flow and pressure control method in a steam methane reformer;

[0036] Figure 3 This is a diagram illustrating the flow and pressure control mechanism in a steam methane reformer according to an exemplary embodiment of the present disclosure.

[0037] Figure 4 This is a diagram illustrating the configuration and operating principle of a steam methane reformer according to another embodiment of the present disclosure;

[0038] Figure 5 It is used to describe according to Figure 4A diagram illustrating a method for controlling the mode of a flow indication controller in a steam methane reformer according to an exemplary embodiment of the present disclosure.

[0039] Figure 6A It is used to describe according to Figure 4 A flowchart of a method in a steam methane reformer according to an exemplary embodiment of the present disclosure;

[0040] Figure 6B This is a flowchart describing the SP value determination logic of the flow indication controller SP calculator in cascade mode according to an exemplary embodiment of the present disclosure;

[0041] Figure 7 It is used to describe according to Figure 4 The present disclosure includes an exemplary embodiment of a flow and pressure control mechanism interlocked with the controller of a steam methane reformer, and a diagram illustrating its effects; and

[0042] Figure 8 A computing system according to an exemplary embodiment of the present disclosure is shown. Detailed Implementation

[0043] In the following, various exemplary embodiments of the present disclosure will be described in detail with reference to the exemplary accompanying drawings. When adding reference numerals to the components in the various drawings, it should be noted that the components are denoted by the same reference numerals even if they are shown in other drawings. Furthermore, in describing exemplary embodiments of the present disclosure, detailed descriptions of well-known features or functions will be excluded so as not to unnecessarily obscure the spirit of the disclosure.

[0044] In describing components of exemplary embodiments according to the present disclosure, terms such as first, second, "A", "B", (a), (b), etc., may be used. These terms are intended only to distinguish one component from another, and they do not limit the nature, order, or sequence of the respective components. Furthermore, unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Terms as defined in commonly used dictionaries should be interpreted as having a meaning equivalent to that in the context of the relevant field and should not be interpreted as having an ideal or overly formal meaning unless expressly defined as such in this application.

[0045] In the following text, reference will be made to Figures 1 to 8 The embodiments of this disclosure are described in detail.

[0046] Figure 1 This is a diagram illustrating the configuration and operating principle of a steam methane reformer according to an exemplary embodiment of the present disclosure.

[0047] refer to Figure 1 The steam methane reformer (SMR) 100 may include a start-up gas supply valve 10, an ultrapure water pump 11, a gas compressor 12, a reformer 13, a converter 14, a gas-liquid separator 15, a pressure swing adsorption (PSA) 16, a burner 17, a circulation valve 18, a pressure element (PE) 19, a pressure control valve (PCV) 20, and a pressure indication controller (PIC) 21.

[0048] The complete reaction formula for the steam methane reforming process, which is a process of reforming natural gas, which is mainly composed of methane, to produce hydrogen, is as follows.

[0049] CH4 + 2H2O -> CO2 + 4H2

[0050] The SMR 100 can go through the initial startup process and reach normal operation.

[0051] During startup, the SMR 100 can execute a series of processes, such as startup gas supply -> internal recirculation -> heating -> pressure increase -> feeding -> PSA operation, and can switch to normal operation when the internal pressure reaches the target value through the process.

[0052] The startup process can be a process in which the pressure in the system fluctuates from a shutdown state of 0 bar to a normal operating pressure of approximately 7-8 bar, and this can be important for maintaining the pressure in the system stably.

[0053] Furthermore, the startup process can be a process in which the pressure in the system fluctuates from a stationary state of 0 bar to any value less than 10 bar. In this case, it may be important to maintain a stable pressure in the system.

[0054] The start-up gas and feed gas can be continuously circulated before normal operation, and some gas can be vented to the outside to maintain internal pressure when necessary. In this process, the start-up gas supply valve 10 can be opened and operated at a certain opening degree. Besides the amount required to maintain pressure, the remaining start-up gas can be continuously vented to the outside through PCV 20.

[0055] The process of generating hydrogen using SMR 100 components will be described in detail below.

[0056] The start-up gas supply valve 10 can be a control valve for supplying the gas used during the start-up of the SMR 100. The start-up gas may include nitrogen (N2), hydrogen (H2), etc.

[0057] The ultrapure water pump 11 can minimize organic matter, conductivity, etc., and can pressurize and output ultrapure water, which is water with almost no impurities. As an example, the ultrapure water pump 11 can pressurize ultrapure water to about 8 bar and output it.

[0058] Gas compressor 12 can pressurize natural gas (the supply fuel for SMR 100) to a certain level and output it. As an example, gas compressor 12 can pressurize natural gas to about 8 bar and output it.

[0059] Pressurized natural gas and pressurized ultrapure water can be supplied to reformer 13.

[0060] Reformer 13 allows natural gas and ultrapure water to react with each other under high pressure / high temperature to produce hydrogen. In other words, reformer 13 can produce carbon dioxide and hydrogen through an endothermic reaction between natural gas and ultrapure water according to the reaction CH4 + 2H2O -> CO2 + 4H.

[0061] According to the reaction CO + H2O → CO2 + H2, converter 14 can generate and output hydrogen (H2) and carbon dioxide (CO2) through the exothermic reaction between the hydrogen produced by reformer 13 and carbon monoxide (CO) and ultrapure water (H2O).

[0062] The gas-liquid separator 15 can remove moisture contained in the output of the converter 14.

[0063] PSA 16 can be a device for separating and refining only hydrogen from the mixed gas produced by reformer 13 and converter 14. In this case, the separated gas other than hydrogen is referred to as waste gas.

[0064] Burner 17 can burn natural gas and exhaust gas to supply the heat required for the endothermic reaction of reformer 13.

[0065] The circulation valve 18 can be a valve used to control the circulation of flow rate B among gas compressor 12, reformer 13, converter 14, and gas-liquid separator 15 during SMR 100 startup. A pipeline can be formed so that the output of gas-liquid separator 15 circulates and supplies to gas compressor 12.

[0066] PCV 20 can be a valve used to control the internal pressure when the SMR 100 starts, and it can be configured to adjust the flow rate C according to the control signal from PIC 21. For this purpose, a pipeline can be installed between the output of the gas-liquid separator 15 and PCV 20. Here, PE 19 is used to measure the pressure of the flow rate in the pipeline between the gas-liquid separator 15 and PCV 20. PE 19 can send a process variable (PV) value as pressure detection information to PIC 21. PIC 21 can output an output (OP) as a command for adjusting PCV 20 based on the PV value. PIC 21 can adjust the opening of PCV 20 until the internal pressure reaches a certain target value.

[0067] When the internal pressure reaches the target value, PIC 21 can adjust the opening of PCV 20 to keep the flow rate A supplied for startup and the flow rate C of the startup gas discharged to the outside the same. When the amount of gas supplied for startup, A, is greater than the amount of gas discharged to the outside, there may be periods of pressure instability. PIC 21 can keep the startup gas supply A and the external discharge C the same, so that the internal pressure can be stabilized at the target value.

[0068] Figure 2 It is used to describe Figure 1 A flowchart of the flow and pressure control method in a steam methane reformer (SMR).

[0069] refer to Figure 1 and Figure 2 When the gas supply process is started, in S210, SMR 100 can open the gas supply valve 10 for starting.

[0070] In the S220, the SMR 100 can activate the PIC 21 in automatic mode to perform internal pressure monitoring.

[0071] In S230, SMR 100 can compare the measured internal pressure with a predetermined target value to determine whether the internal pressure has reached the target value.

[0072] When the determined result is that the internal pressure reaches the target value, in S240, SMR 100 can be configured to control PCV 20 so that the gas flow rate A supplied for startup and the gas flow rate C discharged to the outside remain the same.

[0073] Figure 3 This is a diagram illustrating the flow and pressure control mechanism in a steam methane reformer (SMR) 100 according to an exemplary embodiment of the present disclosure.

[0074] refer to Figure 3As indicated by reference numeral 310 in the attached figure, when starting gas A is supplied, the circulation flow rate B can be increased and the internal pressure of the system can be increased simultaneously.

[0075] Referring to reference numerals 310 and 320, although the circulation flow rate B reaches the predetermined first target value, it may take an additional time t1 until the internal system pressure reaches the predetermined second target value. Furthermore, even if the internal system pressure reaches the second target value, the internal pressure may be unstable during the period t2 when the start-up gas supply is greater than the external emission.

[0076] As shown by reference numeral 330 in the accompanying drawings, the SMR 100 according to an exemplary embodiment of the present disclosure can be configured to control and maintain a balance between the flow rate A of the start-up gas (supplied by adjusting the opening of the PCV 20) and the external discharge flow rate C, so as to stabilize the internal pressure of the system at a second target value.

[0077] Figure 4 This is a diagram illustrating the configuration and operating principle of a steam methane reformer (SMR) according to another embodiment of this disclosure.

[0078] refer to Figure 4 The SMR 400 may include a start-up gas supply valve 10, an ultrapure water pump 11, a gas compressor 12, a reformer 13, a converter 14, a gas-liquid separator 15, a pressure swing adsorption (PSA) unit 16, a burner 17, a circulation valve 18, a pressure element (PE) 19, a pressure control valve (PCV) 20, a pressure indication controller (PIC) 21, a flow indication controller (FIC) 22, a flow control valve (FCV) 23, and an FIC SP calculator 24.

[0079] The SMR 400 according to the exemplary embodiments of this disclosure can operate in any of the following modes: manual mode, automatic mode, and cascade mode. The SMR 400 according to the exemplary embodiments of this disclosure can set the default operating mode to cascade mode.

[0080] In both manual and automatic modes, FIC 22 can operate as an independent controller to control the flow rate of the start-up gas. In manual mode, FIC 22 can be interlocked with PIC 21, and the SP value of FIC 22 can be determined by FIC SP calculator 24 based on the OP value of PIC 21 to control the flow rate of the start-up gas. According to the exemplary embodiments of this disclosure, FIC 22 can be dynamically interlocked with PIC 21 based on real-time changes in internal pressure, thereby providing more organic control over the flow rate of the start-up gas.

[0081] The complete reaction formula for the steam methane reforming process, which reforms natural gas, which is mainly composed of methane, to produce hydrogen, is as follows.

[0082] CH4 + 2H2O -> CO2 + 4H2

[0083] The SMR 400 can go through the initial startup process and reach normal operation.

[0084] During startup, the SMR 400 can execute a series of processes, such as startup gas supply -> internal recirculation -> heating -> pressure increase -> feeding -> PSA operation. When the internal pressure reaches the target value through the process, the SMR 400 can quickly stabilize the internal pressure and switch to normal operating mode via mode switching. Mode switching refers to switching from automatic mode to cascaded mode.

[0085] The startup process can be a process in which the pressure in the system fluctuates from a shutdown state of 0 bar to a normal operating pressure of approximately 7-8 bar, and may be important for maintaining the pressure in the system stably.

[0086] The start-up gas and feed gas can be continuously circulated before normal operation, and some gas can be vented to the outside to maintain internal pressure when necessary. In this process, the start-up gas supply valve 10 can be opened and operated at a certain opening degree. Besides the amount required to maintain pressure, the remaining start-up gas can be continuously vented to the outside through PCV 20.

[0087] The following section provides a detailed description of the process for producing hydrogen using SMR 400 modules.

[0088] The start-up gas supply valve 10 may be a control valve for supplying the gas used during the start-up of the SMR 400. The start-up gas may include nitrogen (N2) and hydrogen (H2).

[0089] The ultrapure water pump 11 can minimize organic matter, conductivity, etc., and can pressurize and output ultrapure water with almost no impurities. As an example, the ultrapure water pump 11 can pressurize ultrapure water to about 8 bar and output it.

[0090] Gas compressor 12 can pressurize natural gas, which is used as fuel for the SMR 400, to a certain level and output it. As an example, gas compressor 12 can pressurize natural gas to about 8 bar and output it.

[0091] Pressurized natural gas and pressurized ultrapure water can be supplied to reformer 13.

[0092] Reformer 13 allows natural gas and ultrapure water to react with each other under high pressure / high temperature to produce hydrogen. In other words, reformer 13 can produce carbon dioxide and hydrogen through an endothermic reaction between natural gas and ultrapure water according to the reaction CH4 + 2H2O -> CO2 + 4H.

[0093] According to the reaction CO + H2O → CO2 + H2, converter 14 can generate and output hydrogen (H2) and carbon dioxide (CO2) through the exothermic reaction between the hydrogen produced by reformer 13 and carbon monoxide (CO) and ultrapure water (H2O).

[0094] The gas-liquid separator 15 can remove moisture contained in the output of the converter 14.

[0095] PSA 16 can be a device for separating and refining only hydrogen from the mixed gas produced by reformer 13 and converter 14. In this case, the separated gas other than hydrogen is called waste gas.

[0096] Burner 17 can burn natural gas and exhaust gas to supply the heat required for the endothermic reaction of reformer 13.

[0097] The circulation valve 18 can be a valve used to control the circulation of flow rate B among gas compressor 12, reformer 13, converter 14, and gas-liquid separator 15 during SMR 400 startup. A pipeline can be formed so that the output of gas-liquid separator 15 circulates and supplies to gas compressor 12.

[0098] PCV 20 can be a valve used to control the internal pressure when the SMR 400 starts, and it can be used to adjust the flow rate C according to the control signal of PIC 21. For this purpose, a pipeline can be set between the output of the gas-liquid separator 15 and PCV 20. Here, PE 19 is used to measure the pressure of the flow rate in the pipeline between the gas-liquid separator 15 and PCV 20. PE 19 sends a process variable (PV) value as pressure detection information to PIC 21. PIC 21 can output an output (OP) as a command for adjusting PCV 20 based on the PV value. In manual or automatic mode, when the internal pressure reaches a certain target value, PIC 21 can switch to a cascaded mode interlocked with FIC 22. The SMR 400 according to an exemplary embodiment of this disclosure may include a function for switching operating modes. Figure 5 The mode switcher 25 is shown in reference numeral 510 in the accompanying drawings. The mode switcher 25 will be described below.

[0099] As an exemplary embodiment of this disclosure, the operating modes may include manual mode, automatic mode, and cascading mode. The default operating mode can be set to any one of manual mode, automatic mode, and cascading mode according to the design of those skilled in the art.

[0100] In addition, when the internal pressure reaches the target value, PIC 21 can be configured to control the supply of start-up gas to a certain minimum value while maintaining the internal pressure stably at the target value, thereby reducing both the flow rate A supplied for startup and the flow rate C of start-up gas discharged to the outside.

[0101] As the gas supplied for startup decreases, PIC 21 can adjust the opening of PCV 20 to reduce the gas flow rate emitted to the outside.

[0102] For example, before entering cascade mode, while controlling the start-up gas flow in manual or automatic mode, the SMR 400 can switch FIC 22 to cascade mode when the internal pressure reaches the target value. The FIC setpoint (SP) calculator 24 can determine the SP value of FIC 22 based on the output (OP) value of PIC 21 in cascade mode and provide the SP value of FIC 22 to FIC 22. In other words, FIC 22 can operate as an independent controller or a slave controller, depending on the operating mode and the operation of PIC 21 as the master controller.

[0103] As described above, the SMR 400 according to an exemplary embodiment of the present invention can adaptively interlock PIC 21 and FIC 22 according to the change in internal pressure during initial startup, thereby minimizing the consumption of startup gas and stabilizing the internal pressure for normal operation more quickly.

[0104] Figure 5 It is used to describe according to Figure 4 A diagram illustrating a method for controlling the mode of a flow indication controller (FIC) in a steam methane reformer (SMR) according to an exemplary embodiment of the present disclosure.

[0105] refer to Figure 5 As indicated by reference numeral 510 in the attached diagram, when the internal pressure reaches a certain target value, FIC 22 can switch from automatic mode (or manual mode) to cascade mode.

[0106] When the operating mode is switched from automatic mode (or manual mode) to cascade mode to prevent abrupt changes in the opening degree of PCV 20, the FIC SP calculator 24 can change the SP value of FIC 22 as follows.

[0107] Typically, the PCV 20 operates with an opening of 20%-80%, and maintains an opening of approximately 50% during normal operation.

[0108] Therefore, preferably, when the OP value of PIC 21 (i.e., the opening rate of PCV 20) becomes 50%, it can be set as the lower limit control value of FIC 22. For example, as shown by reference numeral 520, in cascade mode, the SP lower limit value of FIC 22 can be controlled to 20% of the SP value in normal operation (or automatic mode). As an embodiment of the present invention, in cascade mode, the SP lower limit value of FIC 22 can be controlled to be at the lowest flow level that can stably maintain internal pressure.

[0109] The reason why OP=50% is the standard for PIC 21 is as follows.

[0110] When the OP value of PIC 21 reaches the lower limit of SP of FIC 22 from 25%, PCV 20 can quickly stabilize the internal pressure, but it can operate at 25% opening. This is not the preferred operating method in terms of the opening of the control valve.

[0111] The reason why the lower limit of SP in FIC 22 is set at 20% is to reflect the lower limit of the general control range of 20%-80%.

[0112] For control valves using pneumatic actuators operated by air, an opening change of 2%–5% per second is typically observed. On the other hand, for control valves using electric actuators, an opening change of 5%–10% per second is typically observed.

[0113] Therefore, after PCV 20 is opened, it may take about 10 to 25 seconds to reach 50% opening.

[0114] Figure 6A It is used to describe according to Figure 4 A flowchart of a method in a steam methane reformer (SMR) according to an exemplary embodiment of the present disclosure.

[0115] refer to Figure 4 and Figure 6A When gas supply processing is initiated, in S610 and S620, SMR 400 can activate FIC 22 and PIC 21 in default mode and monitor the system's internal pressure. Here, the default mode can be automatic mode (or manual mode).

[0116] In S630, SMR 400 can compare the measured internal pressure with a predetermined target value to determine whether the internal pressure has reached the target value.

[0117] When the result confirms that the internal pressure has reached the target value, in the S640, the SMR 400 can switch the operating mode of FIC 22 from the default mode to the cascade mode.

[0118] In the S650, the SMR 400 in cascade mode can enable the FIC SP calculator 24.

[0119] In cascade mode, the SMR 400 can reduce the supply of start-up gas and the amount of gas discharged to the outside to a certain level while maintaining the internal pressure at the target value.

[0120] As described above, the method of SMR 400 according to an exemplary embodiment of the present invention can switch the operating mode from the automatic mode, which is the default mode, to the cascade mode based on the internal pressure reaching the target value during initial startup, thereby minimizing the consumption of startup gas, and thereby stabilizing the internal pressure for normal operation more quickly through the interlock between PIC 21 and FIC 22.

[0121] Figure 6B This is a flowchart describing the SP value determination logic of the flow indication controller SP calculator in a cascaded mode according to an exemplary embodiment of the present disclosure.

[0122] refer to Figure 6B When Figure 6A When the FIC SP calculator 24 is turned on in S650, the initial SP value can be set to the current PV value of FIC 22 in S651.

[0123] In S652, the FIC SP calculation unit 24 can check whether the OP value of PIC 21 is greater than or equal to 10%.

[0124] When the check result shows that the OP value of PIC 21 is greater than or equal to 10%, in S653, the FIC SP calculator 24 can check whether the OP value of PIC 21 is greater than 15%.

[0125] When the check result indicates that the OP value of PIC 21 is greater than 15%, in S654, the FIC SP calculator 24 can change the SP value to the value obtained by subtracting the value obtained by dividing the initial SP value by 10 from the existing SP value. Afterwards, the FIC SP calculator 24 can return to S652.

[0126] When the OP value of PIC 21 in S653 is less than or equal to 15%, the FIC SP calculator 24 can return to S652.

[0127] When the check result in S652 indicates that the OP value of PIC 21 is less than 10%, in S655, the FIC SP calculator 24 can change the SP value to a value obtained by adding the value obtained by dividing the initial SP value by 20 to the existing SP value. Afterwards, the FIC SP calculator 24 can return to S652.

[0128] like Figure 6B As shown, according to the SP determination logic of FIC SP calculator 24, FIC SP calculator 24 can set the SP value of FIC 22 to maintain the OP value of PIC 21 at 10% to 15%. Additionally, FIC SP calculator 24 can set the SP value of FIC 22 to ensure that PIC 21 stably maintains its internal pressure. In this paper, the flow rate of the start-up gas is not controlled to 0 to prevent the internal pressure of the system from converging below the target pressure due to a delay until PCV 20 shuts down.

[0129] In this embodiment, the OP value of PIC 21 is maintained at 10% to 15% due to the nature of the control valve, which smoothly performs control within the 10% to 90% range. Specifically, considering the reasons, when the control valve is fully open (100%), the range within which the control valve can be stably controlled is the 10% to 90% opening range. In this document, the excluded opening range of 0% to 10% is the range where control valve control cannot be smoothly performed due to valve seat contact, flow discontinuity, etc., and the remaining excluded opening range of 90% to 100% is the range where control sensitivity is relatively reduced.

[0130] In other words, the reason for maintaining the OP (opening degree of the control value) value of PIC 21 at 10% to 15% within the 10% to 90% opening range where the control valve can be stably controlled relative to the reference flow rate at 100% full opening can be that PIC 21 is operated using the lowest value within the controllable operating range or a value contained within a certain range including that lowest value, and PIC 21 can be operated within the lowest controllable operating range (e.g., 10% to 15%) to minimize the amount of start-up gas discharged / emitted to its exterior.

[0131] Figure 7 It is used to describe according to Figure 4 The present disclosure provides an exemplary embodiment of a flow and pressure control mechanism interlocked with a controller of a steam methane reformer (SMR) and a diagram illustrating its effects.

[0132] refer to Figure 7 As indicated by reference numeral 710 in the attached diagram, when starting gas A is supplied, the circulation flow rate B can be increased and the internal pressure of the system can be increased simultaneously.

[0133] Referring to reference numerals 710 and 720, although the circulation flow rate B reaches the predetermined first target value, an additional time t1 may be required before the system's internal pressure reaches the predetermined second target value. Furthermore, even if the system's internal pressure reaches the second target value, the internal pressure may be unstable during the period t2 when the start-up gas supply is greater than the external discharge. Therefore, it is important to minimize the intervals of internal pressure instability in order to more quickly enter normal operating mode.

[0134] As indicated by reference numeral 730 in the attached figure, when the internal pressure reaches the second target value, the SMR 400 according to the exemplary embodiment of this disclosure can gradually reduce the flow rate A of the start-up gas to minimize the consumption of the start-up gas, while quickly stabilizing the internal pressure of the system to the second target value. At this time, the amount of start-up gas discharged externally can also be reduced.

[0135] Figure 8 A computing system according to an exemplary embodiment of the present disclosure is shown.

[0136] refer to Figure 8 The computing system 800 may include at least one processor 820, a memory 830, a user interface input device 840, a user interface output device 850, a storage device 860, and a network interface 870, which are connected to each other via a bus 810.

[0137] User interface input device 840 and user interface output device 850 can provide a user interface for inputs / outputs with external diagnostic equipment and / or system monitoring devices.

[0138] The network interface 870 can provide a communication device for sending and receiving control signals between the internal components of the steam methane reformer 400.

[0139] Processor 820 may be a central processing unit (CPU) or a semiconductor device that processes instructions stored in memory 830 and / or storage device 860. Memory 830 and storage device 860 may include various types of volatile or non-volatile storage media. For example, memory 830 may include read-only memory (ROM) 831 and random access memory (RAM) 832.

[0140] Therefore, the operation of the methods (or processes) or algorithms described in conjunction with the exemplary embodiments included in the specification can be directly implemented using hardware modules, software modules, or a combination of hardware and software modules, and executed by processor 820. Software modules can reside on storage media (i.e., memory 830 and / or storage device 860), such as RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disks, removable disks, and CD-ROMs. As an example, processor 820 can be formed as part of the aforementioned steam methane reformer 400, and can specifically correspond to... Figure 4 It includes at least one of the flow indicator controller 22 or pressure indicator controller 21.

[0141] An exemplary storage medium may be coupled to a processor 820. The processor 820 can read information from the storage medium and can write information to the storage medium. Alternatively, the storage medium may be integrated with the processor 820. Both the processor and the storage medium may reside in an application-specific integrated circuit (ASIC). The ASIC may reside in the steam methane reformer 400.

[0142] This technology can provide methods and equipment for improving the start-up stability of steam methane reformers and optimizing the amount of circulating gas used.

[0143] In addition, this technology can provide a steam methane reformer configured to adaptively control the flow rate of start-up gas based on the internal pressure of the system, thereby improving start-up stability and optimizing the amount of circulating gas used.

[0144] Furthermore, this technology can provide methods and apparatus for improving the start-up stability of steam methane reformers and optimizing the amount of circulating gas for interlocking pressure and flow indicator controllers to adaptively control the flow indicator controller mode to minimize periods of pressure instability and minimize the amount of start-up gas discharged to the outside.

[0145] In addition, various effects that can be directly or indirectly determined through this disclosure may be provided.

[0146] While this disclosure has been described above with reference to exemplary embodiments and accompanying drawings, it is not limited thereto. Various modifications and alterations may be made by those skilled in the art without departing from the spirit and scope of this disclosure as claimed in the appended claims.

[0147] Therefore, the embodiments described herein are not intended to limit but rather to explain the technical concept of this disclosure, and the scope and spirit of the invention are not limited to the above embodiments. The scope of this disclosure should be interpreted based on the appended claims, and all technical concepts within the scope of the claims should be included within the scope of this disclosure.

Claims

1. A method for controlling a steam methane reformer, the method comprising: Based on the startup of the steam methane reformer, the startup gas is supplied by opening the startup gas supply valve; Activate the pressure indicator controller's operating mode to automatic mode; and Based on the fact that the internal pressure of the steam methane reformer reaches a target value when the start-up gas is supplied, the pressure indicator controller controls the pressure control valve to match the supply flow rate of the start-up gas with the gas flow rate discharged to the outside of the steam methane reformer.

2. The method according to claim 1, further comprising: Based on the internal pressure reaching the target value, the operation mode of the flow indicator controller is switched from automatic mode to cascade mode; and Activate the flow indicator controller setpoint calculator to determine the setpoint of the flow indicator controller based on the output of the pressure indicator controller.

3. The method according to claim 2, in, The flow indicator controller for adjusting the opening of the flow control valve and the pressure indicator controller for adjusting the opening of the pressure control valve are interlocked by switching to the cascade mode based on the operating mode of the flow indicator controller. The flow indicator controller setpoint calculator sets the setpoint so that the pressure indicator controller stably maintains the internal pressure.

4. The method according to claim 3, further comprising: In the cascaded mode, the interlock maintains the internal pressure at the target value while reducing the supply flow rate of the start-up gas.

5. The method according to claim 4, in, The supply flow rate of the start-up gas is reduced to the lower limit set by the flow indicator controller, and The lower limit value is the flow rate when the opening degree of the pressure control valve is 50% in the cascade mode.

6. The method according to claim 4, wherein, In the cascaded mode, the supply flow rate of the start-up gas is reduced to the minimum flow rate level that can stably maintain the internal pressure.

7. The method according to claim 1, in, After the internal pressure reaches the target value, there is a period of time when the supply flow rate of the start-up gas is greater than the gas flow rate discharged to the outside, during which the internal pressure is unstable. Wherein, based on the internal pressure reaching the target value, the supply flow rate of the start-up gas is reduced to a level that minimizes the unstable time period.

8. The method according to claim 1, wherein, The target value is set to any value within the range of greater than 0 bar and less than 10 bar.

9. The method according to claim 1, wherein, The starting gas includes at least one of hydrogen and nitrogen.

10. A non-transitory computer-readable storage medium having a program recorded thereon for performing the method according to claim 1.

11. A steam methane reformer, comprising: A start-up gas supply valve, the supply valve being configured to open upon startup of the steam methane reformer and supply the start-up gas to the interior of the steam methane reformer; A pressure indicator controller is configured to monitor and control changes in the internal pressure of the steam methane reformer when the start-up gas is supplied; and A pressure control valve is configured to adjust its opening degree according to the output of the pressure indicator controller and to discharge the start-up gas to the outside of the steam methane reformer. The pressure indicator controller controls the pressure control valve based on the internal pressure reaching a predetermined target value, so that the supply flow rate of the start-up gas is the same as the discharge flow rate.

12. The steam methane reformer according to claim 11, wherein, When the steam methane reformer is started, the operating mode of the pressure indicator controller is activated to automatic mode.

13. The steam methane reformer according to claim 12, further comprising: A flow control valve is configured to regulate the supply flow rate of the starting gas; A flow indicator controller is configured to control the opening degree of the flow control valve; as well as A flow indicator controller setpoint calculator is configured to determine the setpoint of the flow indicator controller based on the output of the pressure indicator controller. When the internal pressure reaches the target value, the operation mode of the flow indicator controller switches from automatic mode to cascade mode to activate the flow indicator controller setpoint calculator.

14. The steam methane reformer according to claim 13, in, The flow indicator controller and the pressure indicator controller are interlocked with each other based on the operation mode of the flow indicator controller being switched to the cascade mode, and The flow indicator controller setpoint calculator sets the setpoint so that the pressure indicator controller stably maintains the internal pressure.

15. The steam methane reformer according to claim 14, wherein, In the cascaded mode, the pressure indicator controller controls the flow indicator controller to maintain the internal pressure at the target value while reducing the supply flow rate of the start-up gas through the interlock.

16. The steam methane reformer according to claim 15, in, The supply flow rate of the start-up gas is reduced to the lower limit set by the flow indicator controller, and The lower limit value is the flow rate when the opening degree of the pressure control valve is 50% in the cascade mode.

17. The steam methane reformer according to claim 15, wherein, In the cascaded mode, the supply flow rate of the start-up gas is reduced to the minimum flow rate level that can stably maintain the internal pressure.

18. The steam methane reformer according to claim 11, in, After the internal pressure reaches the target value, there is a period of time when the supply flow rate of the start-up gas is greater than the gas flow rate discharged to the outside, during which the internal pressure is unstable. Wherein, based on the internal pressure reaching the target value, the supply flow rate of the start-up gas is reduced to a level that minimizes the unstable time period.

19. The steam methane reformer according to claim 11, wherein, The target value is set to any value within the range of greater than 0 bar and less than 10 bar.

20. The steam methane reformer according to claim 11, wherein, The starting gas includes at least one of hydrogen and nitrogen.

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