System and method for stabilizing the operation of an installation using hydrogen produced with a low carbon source

Abstract

To provide a system and a method for stabilizing a hydrogen flow rate to a downstream process in a facility having a hydrogen storage unit and obtaining electric power from a low carbon energy source.SOLUTION: Determining a hydrogen density and pressure profile in the hydrogen storage unit for different target pure hydrogen flow rates at different time intervals in a time horizon of a profile of available renewable power, determining an operational target pure hydrogen flow rate of hydrogen supply to the downstream process, determining a target direct hydrogen flow rate of hydrogen supply and a target stored hydrogen flow rate of hydrogen supply to the downstream process, and controlling operation of the downstream process based on the operational target hydrogen flow rate.SELECTED DRAWING: Figure 1

Description

Detailed Description of the Invention

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 647500, filed May 14, 2024, the disclosure of which is incorporated herein by reference.

[0002] [Technical field] The present disclosure relates to industrial processes that use hydrogen produced from low-carbon energy sources.

[0003] [Background technology] Traditionally, hydrogen required for downstream processes such as ammonia production and methanol production is produced by processing hydrocarbon feedstocks through methods such as natural gas reforming, partial oxidation of hydrocarbons, or methane cracking, all of which generate carbon dioxide emissions. Other hydrogen sources, such as electrolyzers / electrolysis processes, require only water and electricity. When a renewable energy source supplies electricity to an electrolyzer, hydrogen can be produced without generating carbon emissions. However, because hydrogen-based production processes require a steady state, such as a constant flow rate of hydrogen supply, the use of renewable energy sources can pose challenges when operating electrochemical systems such as electrolyzers.

[0004] Renewable energy sources such as wind or solar power are prone to changes in environmental conditions, such as calm or poor weather. A decrease in wind speed or solar radiation intensity can lead to a decrease in available power. This decrease in power can then reduce the supply of hydrogen produced by hydrogen production sources (e.g., electrolyzers), potentially disrupting the production of end products.

[0005] The operating load of the downstream production process needs to be as stable as possible, so adjustments to the hydrogen flow rate to the downstream production process need to be minimized, taking into account the current and future value of the renewable energy source based on the available renewable energy profile, other available hydrogen sources, and the available hydrogen inventory required to operate within the operating pressure tolerances.

[0006] [Summary of the Invention] Such exemplary systems and methods for stabilizing facility operations using hydrogen produced from low-carbon sources may substantially eliminate one or more problems resulting from limitations or shortcomings in the related art, or at least provide the public with a useful alternative.

[0007] The examples describe systems and methods for stabilizing hydrogen flow to downstream processes in facilities that include hydrogen storage units and derive power from low-carbon energy sources.

[0008] The systems and methods described in the examples may enable efficient production even when a process uses dynamic energy sources, such as renewable energy, to power the process, and the stability of the process is affected by the dynamic energy supply.

[0009] In an embodiment, determining hydrogen density and pressure profiles in the hydrogen storage unit corresponding to different target pure hydrogen flow rates at different time intervals in a time period of the renewable electricity availability profile may include determining the mass of hydrogen produced at each time interval over the time period of interest, determining the relationship between hydrogen pressure and hydrogen density in the hydrogen storage unit, determining the density of hydrogen in the hydrogen storage unit for each target pure hydrogen flow rate at each time interval in the time period of interest, and determining the pressure profile of the hydrogen storage unit at each time interval in the time period of interest.

[0010] In an embodiment, the system and method may include determining hydrogen density and pressure profiles in a hydrogen storage unit for different target pure hydrogen flow rates at different time intervals over a time period of interest for a profile of available renewable electricity; determining a first target pure hydrogen flow rate for hydrogen supply to a downstream process for a predetermined time interval within the time period of interest, the first target pure hydrogen flow rate corresponding to the longest time required for the hydrogen pressure in the hydrogen storage unit to exceed a high or low pressure limit; determining a second target pure hydrogen flow rate for hydrogen supply to the downstream process for a predetermined time interval within the time period of interest, the second target pure hydrogen flow rate corresponding to a pressure profile in the hydrogen storage unit that minimizes deviation from the high or low pressure safety limit of the hydrogen storage unit; setting the larger of the first target pure hydrogen flow rate and the second target pure hydrogen flow rate as an operating target pure hydrogen flow rate; and controlling operation of the downstream process based on the operating target pure hydrogen flow rate.

[0011] In an embodiment, controlling the operation of a downstream process based on the operational target pure hydrogen flow rate may include sending the operational target pure hydrogen flow rate to an advanced regulatory control system, a user interface, or both.

[0012] In embodiments, downstream processes may include ammonia synthesis, methanol synthesis, renewable power, and / or any other process involving the use of one or more hydrogen sources.

[0013] In an embodiment, the system and method may include a non-transitory computer-readable medium having computer-readable instructions stored thereon that, when executed by a processor, cause the processor to: determine hydrogen density and pressure profiles in the hydrogen storage unit for different target pure hydrogen flow rates at different time intervals during a time period of a profile of available renewable electricity; determine a first target pure hydrogen flow rate for supplying hydrogen to a downstream process during a predetermined time interval during the time period of interest, the first target pure hydrogen flow rate corresponding to the longest time required for the hydrogen pressure in the hydrogen storage unit to exceed a high or low pressure limit; determine a second target pure hydrogen flow rate for supplying hydrogen to the downstream process during a predetermined time interval during the time period of interest, the second target pure hydrogen flow rate corresponding to a pressure profile in the hydrogen storage unit that minimizes deviation from a safety limit; set the greater of the first target pure hydrogen flow rate and the second target pure hydrogen flow rate as an operating target pure hydrogen flow rate; and apply the operating target pure hydrogen flow rate to control operation of the downstream process.

[0014] In an embodiment, a process for determining hydrogen density and pressure profiles in a hydrogen storage unit for different target pure hydrogen flow rates at different time intervals over a time period of interest of a profile of available renewable electricity may include a processor to determine the mass of hydrogen produced at each time interval over the time period of interest, determine the relationship between hydrogen pressure and hydrogen density in the hydrogen storage unit, determine the hydrogen density in the hydrogen storage unit at each target pure hydrogen flow rate for each time interval over the time period of interest, and determine the pressure profile of the hydrogen storage unit at each time interval over the time period of interest.

[0015] In an embodiment, operational control of a downstream process may be performed based on the operational target pure hydrogen flow rate, including transmitting the operational target pure hydrogen flow rate to an advanced regulatory control system, a user interface, or both.

[0016] In embodiments, systems and methods are described for regulating the flow of hydrogen produced using a low-carbon energy source to a product manufacturing process in a facility having downstream manufacturing process units, which may include units for ammonia synthesis, methanol synthesis, or other units that involve the use of renewable electricity and / or one or more hydrogen sources. In an embodiment, the system and method may include supplying energy to a facility, wherein at least a portion of the supplied energy is supplied from a low-carbon energy source that is dependent on at least one environmental parameter; estimating availability of energy from the low-carbon energy source for a selected time period using the at least one environmental parameter; forming a hydrogen supply to a downstream manufacturing process unit using at least one of (i) a primary hydrogen supply generated by a hydrogen source powered by the low-carbon energy source and (ii) a supplemental hydrogen supply; controlling the formation of the hydrogen supply using an advanced regulatory controller (ARC), wherein the ARC is configured to generate a setpoint for the hydrogen supply using the estimated available energy; and producing a product by supplying the formed hydrogen supply to the downstream manufacturing process unit, wherein the hydrogen supply to the downstream manufacturing process unit is stabilized by a process described herein.

[0017] In some embodiments, a facility using a low-carbon energy source is described, and the facility may include a downstream manufacturing process unit, a low-carbon energy source dependent on at least one environmental parameter, a hydrogen source powered by the low-carbon energy source, a hydrogen storage unit configured to receive hydrogen from the hydrogen source, a hydrogen supply to the downstream manufacturing process unit fluidly connected to the hydrogen storage unit, a system for stabilizing the hydrogen flow rate to the downstream process as described herein, and a product output. In some embodiments, the downstream manufacturing process unit is an ammonia synthesis unit, a methanol synthesis unit, or other unit that involves the use of renewable electricity and / or one or more hydrogen sources.

[0018] It should be noted that certain disclosed matters have been described broadly herein in order to facilitate understanding of the detailed description that follows, and to allow those skilled in the art to appreciate the technical contributions of those skilled in the art. Of course, the disclosure includes additional features that will be described below, some of which may form the subject matter of the appended claims. [Brief explanation of the drawings]

[0019] Exemplary embodiments of the present disclosure will now be described with reference to the accompanying drawings, in which like elements are numbered similarly and in which: For a full understanding of the present disclosure, please refer to the following detailed description taken in conjunction with the accompanying drawings, in which like elements are numbered similarly and in which: [Figure 1] FIG. 1 illustrates a schematic diagram of a low-carbon process for synthesizing a final product through downstream processes using hydrogen produced by low-carbon energy, according to one embodiment of the present disclosure. [Figure 2] FIG. 2 shows the pressure profile of hydrogen in the hydrogen storage unit 112 for repeated values ​​of target hydrogen flow rate against a sample 24-hour power availability profile. [Figure 3] FIG. 3 shows the safety margins that apply to the upper and lower limits of the operating pressure of the hydrogen storage unit 112. [Figure 4]FIG. 4 shows an illustration of an example method implemented by system 150. DETAILED DESCRIPTION OF THE INVENTION

[0020] [Detailed Description of the Invention] Aspects of the present disclosure provide systems and associated methods for stabilizing and optimizing hydrogen loading to downstream production units, even when hydrogen is produced from low-carbon sources (e.g., electrolyzers) that are subject to high variability due to fluctuations in available renewable energy profiles.

[0021] The particular embodiments of the present disclosure illustrated in the drawings and described in detail below are to be considered as illustrative of the principles of the present disclosure and are not intended to limit the disclosure to that shown and described herein.

[0022] In embodiments, the systems and methods described herein may be implemented in a facility that includes a downstream process or downstream manufacturing process unit. The nature of the downstream process or downstream manufacturing process unit is not limited. In embodiments, the downstream process may include ammonia synthesis, methanol synthesis, or other processes involving the use of renewable power and / or one or more hydrogen sources. In embodiments, the downstream manufacturing process unit may comprise an apparatus for producing or synthesizing a substance. In embodiments, the downstream manufacturing process unit includes one or more reactors. In embodiments, the downstream manufacturing process unit may include, in addition to one or more reactors, one or more heat exchangers or heaters, one or more separators, one or more flow pumps, or any combination thereof desired for the production or synthesis of a desired substance. In embodiments, the downstream manufacturing process unit includes an apparatus configured for ammonia production or synthesis (e.g., an ammonia synthesis unit), an apparatus including a reactor configured for methanol production or synthesis (e.g., a methanol synthesis unit), or other manufacturing apparatus involving the use of renewable power and / or one or more hydrogen sources.

[0023] Referring to FIG. 1 , a non-limiting embodiment of a facility 100 in which the systems and methods described herein may be implemented is shown. In examples, facility 100 may include a downstream manufacturing process unit 120 that uses hydrogen. In examples, downstream manufacturing process unit 120 may also use one or more feed streams 121. In examples, downstream manufacturing process unit 120 may produce one or more product streams 122. In examples, product stream 122 may include ammonia or methanol. In examples, product stream 122 may include other substances.

[0024] In embodiments, low-carbon energy source 10 may be used to provide electrical energy to one or more components of facility 100 to reduce or eliminate carbon emissions. In embodiments, the power supply of low-carbon energy source 10 may be fluctuating and / or unstable, which may affect the power output of low-carbon energy source 10. Because the power output of low-carbon energy source 10 may fluctuate due to external influences, such as weather conditions, the power supply from low-carbon energy source 10 may be interrupted for extended periods of time or may have reduced capacity. In embodiments, in implementing the systems and methods described herein, low-carbon energy source 10 may be used to provide energy to facility 100 even if low-carbon energy source 10 does not always provide a consistent, uninterrupted power supply. Accordingly, it is emphasized that terms such as "providing power" or "providing energy" do not require an uninterrupted supply or power that meets specific minimum requirements.

[0025] In an embodiment, downstream manufacturing process unit 120 receives one or more feed streams 121. In an embodiment, one or more feed streams 121 provide downstream manufacturing process unit 120 with one or more substances that react with hydrogen to produce product stream 122. In an embodiment, downstream manufacturing process unit 120 receives hydrogen supply 116. In an embodiment, hydrogen supply 116 may be supplied by hydrogen supply line 115 fluidly connected to hydrogen supply 116. In an embodiment, hydrogen supply line 115 may be supplied directly by hydrogen supply source 111. Downstream manufacturing process unit 120 may obtain power from low-carbon energy source 10 via power supply line 12 and / or may obtain power from second energy source 20 (e.g., the electrical grid) via power supply line 23. Second energy source 20 may also supply power to hydrogen source 111 via power supply line 21 and to hydrogen storage unit 112, e.g., a storage tank, via power supply line 22. Second energy source 20 may be operationally independent of facility 100, i.e., second energy source 20 is not controlled by or dependent on facility 100.

[0026] In an embodiment, facility 100 may include a hydrogen plant 110. In an embodiment, hydrogen plant 110 may produce hydrogen using a low-carbon process to a hydrogen source 111, from which a direct hydrogen supply line 115 may be supplied. In an embodiment, power for the hydrogen production process may be provided by a low-carbon energy source 10 via a power supply line 11. In one arrangement, hydrogen plant 110 may include a hydrogen source 111 and a hydrogen storage unit 112. In an embodiment, hydrogen source 111 may be an electrolyzer. Hydrogen source 111 may produce hydrogen to a direct hydrogen supply line 115 fluidly connected to a hydrogen supply 116 to a downstream production process unit 120, and / or to a stored hydrogen supply 113 to the hydrogen storage unit 112. The direct hydrogen supply line 115 and the stored hydrogen supply 113 are shown separately for clarity only. A common exhaust line (not shown) from the hydrogen source 111 may be used to selectively direct the flow of hydrogen to either or both of the downstream manufacturing process unit 120 and the hydrogen storage unit 112. It should be noted that the present teachings are not limited to hydrogen plants 110 that use only electrolyzers as the hydrogen source 111 to produce hydrogen for the direct hydrogen supply line 115 and / or the stored hydrogen supply 113. The present teachings are equally applicable to systems or methods for producing hydrogen through low-carbon processes that use electricity.

[0027] In an embodiment, the hydrogen storage unit 112 may provide a supplemental hydrogen supply to the downstream manufacturing process unit 120. In one arrangement, the hydrogen storage unit 112 stores hydrogen and supplies the stored hydrogen to the downstream manufacturing process unit 120 as needed via a hydrogen supply line 114 fluidly connected to a hydrogen supply 116. In an embodiment, one or more valves (not shown) may be used to control the flow rate of hydrogen from the hydrogen supply source 111 via the stored hydrogen supply 113 to the hydrogen storage unit 112. Similarly, in an embodiment, one or more valves (not shown) may be used to control the flow rate of hydrogen from the hydrogen storage unit 112 through the stored hydrogen supply line 114 to the hydrogen supply 116 to the downstream manufacturing process unit 120.

[0028] The amount of hydrogen in the hydrogen storage unit 112 may vary depending on the amount of hydrogen produced by the hydrogen plant 110 and directed to the hydrogen storage unit 112 through stored hydrogen supply 113 and the amount of hydrogen directed to the downstream manufacturing process unit 120 via stored hydrogen supply line 114.

[0029] In some embodiments, depending on the supply available to facility 100, hydrogen storage unit 112 may be supplied by second hydrogen source 30 via second hydrogen supply 32. Additionally, excess hydrogen in hydrogen storage unit 112 may be exported to second hydrogen source 30. Second hydrogen source 30 may also provide a supplemental hydrogen supply to downstream manufacturing process unit 120. For example, hydrogen may be supplied directly from second hydrogen source 30 to downstream manufacturing process unit 120 via direct second hydrogen supply 31. In some embodiments, second hydrogen source 30 may be a hydrogen source that is operationally independent from facility 100. That is, second hydrogen source 30 may have access to a power source and / or hydrogen source that is independent from facility 100.

[0030] In an embodiment, to stabilize the operating load of the downstream manufacturing process unit 120, adjustments to the hydrogen supply line 115 and the direct hydrogen flow rate in the hydrogen supply line 114 from the hydrogen storage unit 112 can be minimized, even when the availability of renewable power fluctuates dynamically due to weather changes and day / night transitions, while taking into account the predicted renewable energy profile and the amount of hydrogen inventory in the hydrogen storage unit 112 that may be required for the operation of the downstream manufacturing process unit 120.

[0031] In an embodiment, facility 100 includes system 150 as described herein. In an embodiment, system 150 uses a multi-step iterative calculation to stabilize and maximize hydrogen loading to downstream production process unit 120 when managing fluctuations in the renewable power profile and, therefore, fluctuations in hydrogen production by hydrogen plant 110. In an embodiment, system 150 may include logic, calculations, algorithms, schemas, microprocessors, memory modules, two-way signal communication devices, display devices, input devices, and other components suitable for receiving, processing, storing, and transmitting information.

[0032] In embodiments, system 150 may include any number of logical, programmatic, and physical components. In embodiments, system 150 may include one or more processors and memories communicatively coupled to each other. In embodiments, one or more input / output devices, such as a monitor, keyboard, speaker, microphone, computer mouse, etc., may be coupled to one or more controllers. In embodiments, system 150 may include one or more communication elements, such as a receiver, transmitter, transceiver, or similar structure, to enable wired and / or wireless communication.

[0033] In an embodiment, the memory associated with system 150 may be a non-transitory computer-readable medium. Any suitable memory technology may be employed to implement the memory, such as, for example, static random access memory (SRAM), synchronous dynamic RAM (SDRAM), non-volatile / flash memory, or any other type of memory capable of storing information.

[0034] In embodiments, the memory may be used to store logical instructions, including, but not limited to, one or more software modules and / or other information sufficient for operation, safety procedures, and / or routine maintenance processes. In embodiments, the logical instructions may be used to execute, control, and / or monitor the operation of the system and / or one or more subcomponents of the system. In embodiments, the memory may store an operating system and one or more software applications, instructions, programs, and / or data to perform the functions provided for the methods and various systems described herein. The operations of any of the described systems may be implemented in hardware, software, or a combination thereof. In the software context, operations refer to computer-executable instructions stored on one or more computer-readable storage media, which, when executed by one or more processors, perform the described operations. Computer-executable instructions may include programs, objects, routines, data structures, components, and the like that perform one or more functions or implement particular abstract data types.

[0035] In an embodiment, system 150 receives or includes (e.g., stored in memory) information 140 related to the operation of facility 100. In an embodiment, information 140, or portions thereof, may be used to implement decisions by system 150. In an embodiment, information 140 may include facility-specific information 141 and / or non-facility-specific information 142. Facility-specific information 141 may include operating parameters, such as current setpoints, of hydrogen source 111, hydrogen storage unit 112, downstream manufacturing process unit 120, other sources required for downstream production units, and / or other components associated with facility 100. Facility-specific information 141 may also include operating parameters, such as pressure, temperature, flow rate, energy usage, etc. Non-facility-specific information 142 may include environmental parameters, such as current weather conditions and forecasts, which may include information regarding temperature, wind speed, wind direction, wind gusts, air pressure, precipitation, cloud cover, humidity, dew point, diurnal cycle, etc. This information may be current, historical, and / or forecasted. Non-facility-specific information may include non-weather related information such as predominant and projected energy usage by other nearby energy consumers, availability of secondary energy source 20, availability of secondary hydrogen source 30, etc. It should be noted that the facility-specific and non-facility-specific information described above is merely exemplary. The design and configuration of facility 100, the geographic location of facility 100, and the infrastructure near facility 100 may require facility-specific and / or non-facility-specific information not explicitly listed above.

[0036] In an embodiment, the system 150 performs an iterative calculation to determine current and future values ​​of pressure in the hydrogen storage unit 112 over a time period given a profile of available renewable power. In an embodiment, using the current and future values ​​of pressure in the hydrogen storage unit 112 over a time period given the fluctuating profile of renewable power, the system 150 determines a target pure hydrogen flow rate to the downstream manufacturing process unit 120 for a given available renewable power profile, and subsequently determines a target direct hydrogen flow rate in the hydrogen supply line 115 and a target stored hydrogen flow rate in the hydrogen supply line 114.

[0037] In an embodiment, the system 150 is configured to dynamically calculate the amount of hydrogen produced by the hydrogen source 111 over the period of the available renewable power profile at a rolling and dynamic frequency. In an embodiment, the frequency may be any frequency that is no longer than the time step at which the power availability profile is updated. This frequency should be long enough to maintain the operation of downstream processes and / or downstream manufacturing process units as stable as possible. For purposes of this description, this frequency may be considered the same as the update frequency of the renewable energy profile. This is merely an example.

[0038] The frequency of resetting the target net direct hydrogen flow rate for the hydrogen supply 116, and subsequently the target direct hydrogen flow rate in the hydrogen supply line 115 and the target stored hydrogen flow rate in the hydrogen supply line 114, may depend on the volume of the hydrogen storage unit 112, the nominal capacity of the downstream manufacturing process unit 120, and / or the time required for the pressure in the hydrogen storage unit 112 to reach upper or lower constraints. In an embodiment, the system 150 may be configured to perform calculations to determine the magnitude and frequency of changes in the maximum target net direct hydrogen flow rate for the hydrogen supply 116 to the downstream manufacturing process unit 120, and subsequently the magnitude and frequency of changes in the maximum target direct hydrogen flow rate in the hydrogen supply line 115 and the maximum target stored hydrogen flow rate in the hydrogen supply line 114, which calculations may be based on thermodynamics and first principles.

[0039] In an embodiment, the system 150 is configured to predict the mass and pressure of hydrogen in the hydrogen storage unit 112 for a time period of interest given a profile of available renewable electricity, and may use this information to set a maximum target pure hydrogen flow rate for maximum hydrogen supply 116 to the downstream manufacturing process unit 120, and subsequently set a target direct hydrogen flow rate in the hydrogen supply line 115 and a target stored hydrogen flow rate in the hydrogen supply line 114.

[0040] FIG. 4 shows a flow chart of an example of a process that may be performed by system 150, which is described in more detail below.

[0041] In an embodiment, the system 150 is configured to perform iterations using different assumed values ​​for the target pure hydrogen flow rate for the hydrogen supply 116 to the downstream manufacturing process unit 120, ranging from the turndown capacity of the downstream manufacturing process unit 120 to its nominal maximum capacity. In each iteration, the target pure direct hydrogen flow rate for the hydrogen supply 116 may be increased or decreased incrementally by a predetermined amount, which may depend on the capacity of the downstream manufacturing process unit 120.

[0042] In an embodiment, the system 150 receives one or more of the following inputs 401 for use in each iteration of calculating the target net direct hydrogen flow rate for the hydrogen supply 116 to the downstream manufacturing process unit 120:

[0043] A profile of available renewable electricity over the period under consideration, as provided by operators of 10 low-carbon energy sources; the pressure in the hydrogen storage unit 112 at the beginning of the same period of interest, The efficiency of the hydrogen source 111, defined as the rate of hydrogen production by the hydrogen source 111 as a function of available power; the capacity of the hydrogen storage unit 112, the allowable operating pressure range of the hydrogen storage unit 112; · Assumed target pure hydrogen flow rate for hydrogen supply 116 to downstream manufacturing process units 120.

[0044] As shown in FIG. 4, at 402, the system 150 may determine a target value for the pure hydrogen flow rate for the hydrogen supply 116.

[0045] Step 1—In an embodiment, based on the efficiency of the hydrogen source 111 and an assumed target pure hydrogen flow rate for the hydrogen supply 116 to the downstream production process unit 120, the system 150 determines the mass of hydrogen to be produced in each time interval over the time period for which the renewable power production profile is available. In this manner, the system 150 can establish a profile of hydrogen flow rate from the hydrogen source 111 to the hydrogen storage unit 112 as a function of time over the entire time period for which the renewable power profile is available.

[0046] Step 2—In an embodiment, the system 150 determines the relationship between pressure and density of hydrogen in the hydrogen storage unit 112 based on gas law data at 40° C. and the range of operating pressures between the lower and upper limits of the hydrogen storage unit 112.

[0047] Step 3—In an embodiment, the system 150 determines the density of hydrogen in the hydrogen storage unit 112 at the beginning of the time period for which the profile of available renewable power is given based on the pressure in the hydrogen storage unit 112 at the beginning of the time period for which the profile of available renewable power is given. For each iteration of the target net direct hydrogen flow rate for the hydrogen supply 116 to the downstream manufacturing process unit 120, the system 150 may determine the density of hydrogen in the hydrogen storage unit 112 at each time interval over the entire time period for which the profile of available renewable power is given. In an embodiment, the density of hydrogen in the hydrogen storage unit 112 is determined based on the net change in hydrogen mass in the hydrogen storage unit 112 and the volume of the hydrogen storage unit 112. In this manner, at the beginning of the time period for which the profile of available renewable power is given, the system 150 can set a hydrogen density profile in the hydrogen storage unit 112 for the entire time period for which the profile of available renewable power is given.

[0048] Step 4—In an embodiment, based on the hydrogen density profile within the hydrogen storage unit 112 determined in step 3, the system 150 may determine a pressure profile for the hydrogen storage unit 112 at each time interval throughout the time period of interest given the profile of available renewable electricity. In an embodiment, the pressure profile for the hydrogen storage unit 112 may be determined based on a regression analysis of gas law data obtained based on first principles as described in step 2 above.

[0049] In an embodiment, via steps 3 and 4 above, the system 150 sets hydrogen density and pressure profiles in the hydrogen storage unit 112 for each assumed value of the target pure hydrogen flow rate for the hydrogen supply 116 to the downstream manufacturing process unit 120 at each iteration, for each time interval during the time period of interest given the profile of available renewable electricity.

[0050] In an embodiment, the system 150 may repeat steps 1 through 4 above for each successively assumed value of the target pure hydrogen flow rate for the hydrogen supply 116 to the downstream manufacturing process unit 120. In this manner, the system 150 can establish a hydrogen density and pressure profile within the hydrogen storage unit 112 over the entire time period of interest given the profile of available renewable electricity.

[0051] In an embodiment, based on the calculated density and pressure profiles for the hydrogen storage unit 112 over the entire time period of interest given the profile of available renewable electricity, the system 150 can determine a target pure hydrogen flow rate value for the hydrogen supply 116 to the downstream manufacturing process unit 120 for a given time interval.

[0052] In some embodiments, in making this determination, system 150 may consider a safety margin for hydrogen storage unit 112. In some embodiments, the safety margin for hydrogen storage unit 112 may be defined by a user and / or pre-uploaded to system 150. In some embodiments, system 150 applies the safety margin to upper and lower operating pressure limits for hydrogen storage unit 112.

[0053] In an embodiment, to determine the value of the target pure hydrogen flow rate of the hydrogen supply 116 to the downstream manufacturing process unit 120 for a given time interval, the system 150 considers at least one of two criteria described below and selects the best target hydrogen flow rate to the downstream manufacturing unit.

[0054] Criterion 1—As shown in FIG. 2 , for each iterative target hydrogen flow rate calculation, system 150 analyzes the pressure profile over the time period of the renewable energy profile and plots the pressure profile over the time period. In some embodiments, system 150 compares each calculated pressure value to the pressure value of the design high- or low-pressure limit of hydrogen storage unit 112. In some embodiments, system 150 determines the time it takes for the pressure of hydrogen in hydrogen storage unit 112 to exceed the high- or low-pressure limit. In some embodiments, these determined time values ​​may be stored in an array. In some embodiments, system 150 then selects the target pure hydrogen flow rate for hydrogen supply 116 to downstream manufacturing process unit 120 as the maximum value of all elements in the array.

[0055] Criterion 2—In each iteration using the assumed target hydrogen flow rate, the system 150 determines the total deviation (area under the curve, shown in FIG. 3 , the shaded area) of the pressure profile of the hydrogen storage unit 112 from the allowable pressure limits calculated based on a user-defined safety margin (plus or minus) from the upper and lower design safe pressure limits of the hydrogen storage unit 112 over the time range of the renewable power profile. In an embodiment, the system 150 stores in an array the calculated total deviation (area under the curve) of each pressure profile from the upper or lower safe pressure limits. Each of these calculations represents a time point when the pressure profile of the hydrogen storage unit 112 crosses the upper or lower safe pressure limits of the hydrogen storage unit 112. In an embodiment, the system 150 determines the corresponding pressure profile with the smallest deviation from the safe limits (i.e., the smallest area under the curve) as the optimal iteration target pure hydrogen flow rate for the hydrogen supply 116.

[0056] In an embodiment, the system 150 selects the greater of the two target hydrogen flow rates calculated by Criterion 1 and Criterion 2 as the operational target pure hydrogen flow rate to the downstream manufacturing process unit 120 .

[0057] In an embodiment, system 150 determines a target flow rate value for the stored hydrogen flow rate in hydrogen supply line 114 based on maintaining the hydrogen pressure in hydrogen storage unit 112 within a pressure range that results in the most economical operation of hydrogen storage unit 112. The value of this pressure range may be an input to system 150 based on design parameters. In an embodiment, based on the stored hydrogen flow rate in target hydrogen supply line 114 and the target pure hydrogen flow rate for hydrogen supply 116 to downstream manufacturing process unit 120, system 150 determines a target flow rate value for direct hydrogen supply line 115 as the difference between the target pure hydrogen flow rate for hydrogen supply 116 and the stored hydrogen flow rate in hydrogen supply line 114.

[0058] In an embodiment, the system 150 is configured to automatically recalculate the target pure hydrogen flow rate for the hydrogen supply 116 to the downstream manufacturing process unit 120, thereby taking into account the updated renewable electricity production profile.

[0059] In an embodiment, a plant operator using user interface 170 may override the automatic recalculation of target pure hydrogen supply 116 and manually cause system 150 to recalculate the target direct hydrogen flow rate in hydrogen supply line 115 and the target stored hydrogen flow rate in hydrogen supply line 114 to downstream manufacturing process unit 120 whenever necessary for plant operation.

[0060] In an embodiment, at 403, the system 150 generates one or more of the following outputs: 1. an operational target pure hydrogen flow rate for the hydrogen supply 116; 2. a target direct hydrogen flow rate in the hydrogen supply line 115 and a target stored hydrogen flow rate in the hydrogen supply line 114 to the downstream manufacturing process unit 120; and 3. a time interval for recalculating a new target direct hydrogen flow rate in the hydrogen supply line 115 and a target stored hydrogen flow rate in the hydrogen supply line 114 to the downstream manufacturing process unit 120.

[0061] In an embodiment, the output of the system 150 is used to produce a set point for operation of the facility 100 .

[0062] In some embodiments, facility 100 may include an Advanced Regulatory Control System (ARC) 130. In some embodiments, ARC 130 may include logic, calculations, algorithms, schemas, microprocessors, memory modules, two-way signal communication devices, display devices, input devices, and other components suitable for receiving, processing, storing, and transmitting information.

[0063] In an embodiment, the ARC 130 may be configured to determine one or more set points 131 for one or more operations of the facility 100. The ARC 130 may determine the set point(s) based on a predicted renewable energy profile for the availability of energy from the low-carbon energy source 10 and / or the second energy source 20. The ARC 130 may also determine the set point(s) 131 based on a target pure hydrogen flow rate for the hydrogen supply 116 to the downstream manufacturing process unit 120. As used herein, a "set point" refers to a value associated with a desired output, response, behavior, or operating state of a process component. A set point may be a value, a range of values, an upper limit, or a lower limit. "Control" refers to adjusting, stopping, starting, regulating, increasing, decreasing, and / or maintaining one or more states, conditions, and / or parameters associated with a particular operation. As described further below, the set point(s) 131 are sent to a distributed control system (hereinafter, DCS) 160 of the facility 100.

[0064] In an embodiment, the ARC 130 may use the information 140 to determine one or more set points 131 .

[0065] In an embodiment, the ARC 130 may determine and / or control the increase or decrease in the flow rate of hydrogen from the primary hydrogen source 111 to the hydrogen storage unit 112, the increase or decrease in the flow rate of hydrogen from the primary hydrogen source 111 to the downstream manufacturing process unit 120, and / or the increase or decrease in the flow rate of hydrogen from the hydrogen storage unit 112 to the downstream manufacturing process unit 120.

[0066] In an embodiment, the ARC 130 may set one or more set points 131 for the facility 100 to help maintain stability of downstream processes and / or downstream manufacturing process units, even when the predicted energy profile for the low-carbon energy source 10 exhibits high variability over a period of time. In setting the one or more set points 131, the ARC 130 may consider one or more facility-specific information 141, such as the minimum power required to operate all equipment in the facility 100, the operating ranges of all equipment in the facility 100, including the allowable ramp rates and minimum turndown ratios of the downstream manufacturing process units 120, and the availability of hydrogen in the hydrogen storage unit 112. In setting the one or more set points 131, the ARC 130 may also consider one or more non-facility-specific information 142, such as the availability of power from the second energy source 20, the availability of hydrogen from the direct second hydrogen supply 115, and the requirements of the downstream manufacturing process units 120.

[0067] The ARC130 can also accommodate downstream dynamic mismatches between the predicted power profile and the actual available renewable energy, which may cause violations in the pressure within the hydrogen storage unit or the operation of downstream equipment, within an acceptable range.

[0068] In some embodiments, system 150 is used in conjunction with an appropriate advanced process control strategy. In some embodiments, ARC 130 receives one or more outputs of system 150 and establishes one or more setpoints 131. For example, ARC 130 may receive an operational target for hydrogen flow rate for hydrogen supply 116 determined by system 150 via 152. In some embodiments, ARC 130 may generate one or more setpoints 131 based on the target for hydrogen flow rate for hydrogen supply 116 received from system 150 to send to distributed control system (DCS) 160 for control of downstream manufacturing process units 120. In some embodiments, ARC 130 may predict whether the operational target for hydrogen flow rate determined by system 150 will violate any downstream process operational constraints. If no operational constraints are violated, ARC 130 may adopt the operational target value communicated via 152 as the setpoint and send it to DCS 160 as 131. If the ARC 130 determines that the target hydrogen flow rate determined by the system 150 violates downstream process operational constraints, the ARC 130 may modify the setpoint of the controller of the downstream manufacturing process unit 120 to adjust the operating target hydrogen flow rate, and may generate an appropriately modified target setpoint as 131 and send it to the DCS 160 of the downstream manufacturing process unit 120. In response, the DCS 160 may send a control signal 161 to the downstream manufacturing process unit 120.

[0069] In an embodiment, the output of system 150 is sent to a factory operator via 151 to user interface 170. In an embodiment, the output of system 150 may be used as an operational target for the green hydrogen flow rate for hydrogen supply 116 to downstream manufacturing process units 120. In an embodiment, using user interface 170, an operator may manually communicate set points and / or set point adjustments 171 to DCS 160 for the hydrogen flow rate to downstream manufacturing process units 120. In response, DCS 160 may send control signals 161 to downstream manufacturing process units 120.

[0070] In an embodiment, the system 150 is configured to further stabilize the operating load of downstream manufacturing process units 120 by making minimal adjustments to the hydrogen flow rate while taking into account the current and future values ​​of the renewable energy source (based on weather forecasts) and the hydrogen inventory in the storage drums required to operate within the operating pressure tolerances.

[0071] In an embodiment, the system 150 provides a forecast of the amount of change in the target pure hydrogen flow rate relative to the hydrogen supply 116, which helps stabilize the operation of the downstream manufacturing process unit 120 even when the renewable power source is subject to dynamic fluctuations due to weather changes and day / night transitions.

[0072] In an embodiment, the facility 100 may have available to it a second energy source 20 in some circumstances. The second energy source 20 may include an electrical grid. Note that any excess electricity generated by the low-carbon energy source 10 may be fed to the electrical grid via energy connection 14. The second energy source 20 may also include a bank of batteries that are charged by the low-carbon energy source 10 and / or by the electrical grid via energy connection 24. As noted above, in some circumstances, the facility 100 may have available to it a second hydrogen supply 30. If provided, the second hydrogen supply 30 may provide a supplemental hydrogen supply to the downstream production process unit 120. This supplemental hydrogen supply may be provided instead of, or in addition to, the supplemental hydrogen supply line 114 from the hydrogen storage unit 112. Note that any excess hydrogen produced by the hydrogen supply source 111 or other hydrogen production device may be fed to the second hydrogen supply 30 via a second hydrogen supply 33 or other fluid line. The ARC 130 may adjust the use of energy from the second energy source 20 and the use of hydrogen from the second hydrogen source 30 depending on the low carbon power availability profile and the production of hydrogen by the hydrogen source 111 .

[0073] As previously mentioned, non-equipment specific information 142 may relate to one or more environmental parameters. In an embodiment, system 150 also receives equipment specific information 141. Equipment specific information 141 may relate to the aforementioned operating parameters.

[0074] It should be noted that the above-described apparatuses, devices, components, and systems are merely illustrative of apparatuses, devices, components, and systems designed and configured to perform their respective tasks. For example, an electrolyzer is just one example of an apparatus that may be used to generate hydrogen. Other hydrogen sources may use renewable liquid reforming, high-temperature water splitting, photobiological water splitting, photoelectrochemical water splitting, etc. Therefore, the present teachings are not limited to the above-described apparatuses, devices, components, systems, or processes used therein.

[0075] As used herein, the term "low-carbon energy" refers to energy sources that do not use hydrocarbons as a primary energy source. Examples of low-carbon power sources include, but are not limited to, solar power, wind power, tidal power, geothermal power, hydroelectric power, nuclear power, and hydrogen power. It should be noted that the term "low-carbon energy" sources also includes power sources that do not emit carbon, i.e., "zero-carbon energy sources."

[0076] The words "comprising" and "comprises" as used throughout the claims shall be interpreted to mean "including but not limited to" and "including but not limited to," respectively.

[0077] As used herein, the term "substantially" means "in large part, but not entirely, of what is specified."

[0078] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

[0079] As used herein, the term "about" with respect to a particular parameter is inclusive of the stated value and has the meaning dictated by the context (e.g., includes the degree of error associated with measurement of the particular parameter).

[0080] As used herein, the term "and / or" is intended to include any and all combinations of one or more of the associated listed items.

[0081] The foregoing description has been directed to particular embodiments of the present disclosure for purposes of illustration and description. However, it will be apparent to those skilled in the art that many modifications and variations can be made to the above embodiments without departing from the scope of the present disclosure. It is intended that the following claims be construed to embrace all such modifications and variations.

Claims

1. 1. A method for stabilizing hydrogen flow to a downstream process in a facility that includes a hydrogen storage unit and derives power from a low-carbon energy source, comprising: determining hydrogen density and pressure profiles within the hydrogen storage unit for different target pure hydrogen flow rates at different time intervals over a time period corresponding to a profile of available renewable electricity; determining a first target pure hydrogen flow rate for hydrogen supply to the downstream process for a predetermined time interval within the time period of interest, the first target pure hydrogen flow rate corresponding to the longest time required for the pressure of the hydrogen in the hydrogen storage unit to exceed a high or low pressure limit; determining a second target pure hydrogen flow rate for the hydrogen supply to the downstream process for a predetermined time interval within the time period of interest, the second target pure hydrogen flow rate corresponding to a pressure profile of the hydrogen storage unit that minimizes deviation from a safety limit; setting the larger of the first target pure hydrogen flow rate and the second target pure hydrogen flow rate as an operational target pure hydrogen flow rate; controlling the operation of the downstream process based on the target pure hydrogen flow rate; A method comprising:

2. 2. The method of claim 1, wherein determining hydrogen density and pressure profiles within the hydrogen storage unit for different target pure hydrogen flow rates at different time intervals over a time period spanning a profile of available renewable electricity comprises: determining the mass of hydrogen produced at each time interval over the time period of interest; determining a relationship between the pressure and the density of hydrogen in the hydrogen storage unit; determining a density of the hydrogen in the hydrogen storage unit at each target pure hydrogen flow rate for each time interval over the time period of interest; determining the pressure profile of the hydrogen storage unit at each time interval during the time period of interest; A method comprising:

3. 2. The method of claim 1, wherein controlling the operation of the downstream process based on the operational target pure hydrogen flow rate includes sending the operational target pure hydrogen flow rate to an advanced regulatory control system, a user interface, or both.

4. 10. The method of claim 1, wherein the downstream process comprises ammonia synthesis or methanol synthesis.

5. 1. A system for stabilizing hydrogen flow to a downstream process in a facility that includes a hydrogen storage unit and that derives power from a low-carbon energy source, the system comprising: a non-transitory computer-readable medium having computer-readable instructions stored therein, the instructions, when executed by a processor, causing the processor to: determining hydrogen density and pressure profiles within the hydrogen storage unit for different target pure hydrogen flow rates at different time intervals over a time period covered by a profile of available renewable electricity; determining a first target pure hydrogen flow rate for hydrogen supply to the downstream process for a predetermined time interval within the time period of interest, the first target pure hydrogen flow rate corresponding to the longest time required for the pressure of the hydrogen in the hydrogen storage unit to exceed a high or low pressure limit; determining a second target pure hydrogen flow rate for hydrogen supply to the downstream process for a predetermined time interval within the time period of interest, the second target pure hydrogen flow rate corresponding to a pressure profile of the hydrogen storage unit that minimizes deviation from a safety limit; setting the larger of the first target pure hydrogen flow rate and the second target pure hydrogen flow rate as an operational target pure hydrogen flow rate; applying the operational target pure hydrogen flow rate to control the operation of the downstream process; The system.

6. 6. The system of claim 5, wherein determining hydrogen density and pressure profiles in the hydrogen storage unit for different target pure hydrogen flow rates at different time intervals over a time period covered by a profile of available renewable electricity comprises: determining the mass of hydrogen produced at each time interval over the time period of interest; determining a relationship between the pressure and the density of hydrogen in the hydrogen storage unit; determining a density of the hydrogen in the hydrogen storage unit at each target pure hydrogen flow rate for each time interval over the time period of interest; determining the pressure profile of the hydrogen storage unit at each time interval during the time period of interest; Including, the system.

7. 6. The system of claim 5, wherein controlling the operation of the downstream process based on the operational target pure hydrogen flow rate includes sending the operational target pure hydrogen flow rate to an advanced regulatory control system, a user interface, or both.

8. 6. The system of claim 5, wherein the downstream process comprises ammonia synthesis or methanol synthesis.

9. 1. A method for producing a product using a low carbon energy source, the product being produced by a facility having downstream manufacturing process units, the method comprising: supplying energy to the facility, wherein at least a portion of the supplied energy is supplied from a low carbon energy source that is dependent on at least one environmental parameter; using the at least one environmental parameter to estimate the availability of energy from the low-carbon energy source for a selected time period; and forming a hydrogen supply to the downstream manufacturing process unit using at least one of: (i) a primary hydrogen supply generated by the low-carbon energy source-driven hydrogen source; and (ii) a supplemental hydrogen supply; controlling the formation of the hydrogen supply using an advanced regulatory controller (ARC), the ARC configured to generate a set point for the hydrogen supply using the estimated energy availability; and supplying the formed hydrogen supply to the downstream manufacturing process unit to produce a product; 10. The method of claim 1, wherein the hydrogen supply to the downstream manufacturing process unit is stabilized by the process of claim 1.

10. 10. The method of claim 9, wherein the product is ammonia or methanol.

11. 1. A facility that uses a low carbon energy source, the facility comprising: a downstream manufacturing process unit; a low-carbon energy source that depends on at least one environmental parameter; a hydrogen source powered by said low-carbon energy source; a hydrogen storage unit configured to receive hydrogen from the hydrogen source; a hydrogen supply to the downstream manufacturing process unit, the hydrogen supply fluidly connected to the hydrogen storage unit; a system for stabilizing hydrogen flow to a downstream process; Product output and Including, The system for stabilizing the hydrogen flow rate comprises: determining hydrogen density and pressure profiles within the hydrogen storage unit for different target pure hydrogen flow rates at different time intervals over a time period covered by a profile of available renewable electricity; determining a first target pure hydrogen flow rate for hydrogen supply to the downstream process for a predetermined time interval within the time period of interest, the first target pure hydrogen flow rate corresponding to the longest time required for the pressure of the hydrogen in the hydrogen storage unit to exceed a high or low pressure limit; determining a second target pure hydrogen flow rate for hydrogen supply to the downstream process for a predetermined time interval within the time period of interest, the second target pure hydrogen flow rate corresponding to a pressure profile of the hydrogen storage unit that minimizes deviation from a safety limit; setting the larger of the first target pure hydrogen flow rate and the second target pure hydrogen flow rate as an operational target pure hydrogen flow rate; applying the operational target pure hydrogen flow rate to control the operation of the downstream process; A facility configured to:

12. 12. The facility of claim 11, wherein the downstream manufacturing process unit comprises an ammonia synthesis unit or a methanol synthesis unit.

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