Devices and systems for reducing oxygen concentration in primary gas stream and related methods

Abstract

Apparatus and systems are provided for reducing oxygen concentration in a primary gas stream, comprising a. A primary gas stream channel having a primary gas inlet for the primary gas stream and a primary gas outlet for the deoxygenated primary gas stream; b. A reactant gas flow channel comprising a reactant gas inlet at a first end and connected at a second end to the main gas flow channel so as to allow injection of reactant gas into the main gas flow channel, and further comprising a mass flow control device downstream of the reactant gas inlet; c. A reactor component arranged in the main gas flow channel downstream of the connection location and upstream of the main gas flow outlet; and d. A control unit adapted to control the mass flow control means based on the inlet process conditions of the main gas stream and / or the outlet process conditions of the deoxygenated main gas stream to control the injection flow of the reaction gas injected into the main gas stream in the main gas stream channel; the invention also provides a related method.

Description

Technical Field

[0001] The present disclosure relates to a device and a system for reducing the oxygen content in a main gas flow (such as a gas flow mainly composed of nitrogen or carbon dioxide), and in particular to a device or system including a control unit for controlling the injection flow rate of a reaction gas injected into the main gas flow, and to related methods. Background Art

[0002] Deoxygenation units remove oxygen from the main gas stream. They do this by forcing the oxygen to react with the reactive gas through reactor components (such as a catalytic bed), which lowers the reaction barrier between the oxygen and the reactive gas. For the reactive gas, two types of solutions are possible:

[0003] 1. The reaction gas is the same as the main gas.

[0004] 2. The reaction gas is different from the main gas.

[0005] In a second type of solution, the reaction gas must be injected into the main gas flow before entering the reactor components. The amount of reaction gas injected is usually calculated based on nominal conditions and the stoichiometric relationship between oxygen and reaction gas, i.e., it is assumed that the reaction is perfect and all oxygen is expected to react. However, this can lead to overuse of reaction gas if the application does not require complete deoxygenation, or likewise, insufficient deoxygenation if the application does require a slightly overstoichiometric reaction gas dosage to remove all oxygen. This makes the overall deoxygenation process correspondingly inefficient or unsatisfactory.

[0006] Furthermore, the reactive gas source is not typically considered in the operation of the deoxygenator. Depending on the type of source, this can result in an on / off control strategy that can significantly impact the performance and lifetime of the reactive gas source / generator.

[0007] There exists a need in the industry for a second type of improved solution. Summary of the invention

[0008] The object of the present disclosure is to provide a device according to claim 1 and a system according to claim 11 , and to provide a related method for controlling a device or a system according to claim 20 .

[0009] In a first aspect of the present disclosure, a device for reducing the oxygen concentration in a main gas or a main gas flow is disclosed. The system comprises

[0010] a. a main gas flow channel, the main gas flow channel having a main gas flow inlet for the main gas flow and a main gas flow outlet for the main gas flow that has been deoxygenated;

[0011] b. a reactant gas flow channel comprising a reactant gas inlet at a first end for reactant gas flow and connected (e.g., fluidly connected) to a main gas flow channel at a second end at a connection location so as to allow injection of reactant gas into the main gas flow channel, the reactant gas flow channel comprising a mass flow control device downstream of the reactant gas inlet;

[0012] c. a reactor member arranged in the main gas flow channel downstream of the connection location and upstream of the main gas flow outlet;

[0013] d. A control unit adapted to control the mass flow control device based on the inlet process conditions of the main gas flow and / or the outlet process conditions of the deoxygenated main gas flow so as to control the injection flow rate of the reaction gas injected into the main gas flow in the main gas flow channel to the desired reaction gas flow rate.

[0014] The advantage is that the reactive gas can be used more efficiently and overuse can be avoided. Furthermore, it is expected that the performance and lifetime of the associated reactive gas generator will be improved.

[0015] The mass flow control device may, for example, comprise at least one valve.

[0016] The reactor component may, for example, comprise a reactor chamber or vessel, for example comprising a catalytic bed.

[0017] According to a preferred embodiment, the control unit is adapted to calculate a required reactive gas flow rate to be injected into the primary gas flow based on the primary gas flow at the primary gas flow inlet, the oxygen concentration at the primary gas flow inlet and a required ratio of reactive gas concentration to oxygen concentration.

[0018] For example, the desired ratio of reactant gas concentration to oxygen concentration may be constant.

[0019] Alternatively, the desired ratio of reactant gas concentration to oxygen concentration may depend on a target oxygen concentration of the deoxygenated primary gas stream.

[0020] According to a preferred embodiment, the required ratio of the reaction gas concentration to the oxygen concentration depends on the flow load of the device (or the system according to the second aspect). The flow load of the device (or system) can, for example, be expressed as a fraction of the maximum flow or nominal design flow of the device (or system), for example, a percentage.

[0021] According to a preferred embodiment, the control unit is adapted to calculate the required reactive gas flow rate to be injected into the primary gas flow based on the actual oxygen concentration of the deoxygenated primary gas flow.

[0022] According to a preferred embodiment, the control unit is adapted to calculate a required reactive gas flow rate to be injected into the primary gas flow based on an actual reactive gas concentration of the deoxygenated primary gas flow.

[0023] According to a preferred embodiment, the control unit is adapted to calculate a required reactive gas flow rate to be injected into the primary gas flow based on an actual oxygen concentration and an actual reactive gas concentration of the deoxygenated primary gas flow.

[0024] According to a preferred embodiment, controlling the mass flow control device by the control unit comprises providing at least periodically or continuously a first flow set point value of a desired flow of reactant gas to be injected to the mass flow control device.

[0025] According to a preferred embodiment, the control unit is further adapted to control the flow rate of the reaction gas entering the reaction gas flow channel from the reaction gas inlet.

[0026] In a second aspect of the present disclosure, a system for reducing the oxygen concentration in a main gas flow is disclosed, the system comprising an apparatus according to any one of the embodiments of the first aspect, and also comprising a reaction gas generator connected to (preferably fluidly connected to) a reaction gas inlet and a reaction gas buffer optionally arranged downstream of the reaction gas generator and upstream of the reaction gas inlet, wherein the control unit is also suitable for controlling the flow rate of the reaction gas generator.

[0027] The reactant gas generator may be, for example, a hydrogen or carbon dioxide generator, such as a hydrogen electrolyser.

[0028] According to a preferred embodiment, controlling the flow rate of the reaction gas generator comprises providing, preferably by the control unit at least periodically or continuously, a second flow rate set point value of the reaction gas flow to be generated to the reaction gas generator.

[0029] For the purposes of this disclosure, the control unit may be a single control unit or may comprise two or more distributed individual control units. Throughout this specification, this is abstracted. For example, a control unit adapted to control the flow of a reaction gas generator and a control unit adapted to control a mass flow control device in order to control the injection flow of a reaction gas injected into the main gas flow in the main gas flow channel may be the same control unit or different control units. Preferably, these control units are the same single central control unit.

[0030] According to a preferred embodiment, the second flow set point value is a preferably time-dependent function, such as a polynomial function, such as a linear function, of at least one first flow set point or a group of first flow set points.

[0031] The second flow set point value may be based on or derived from at least one first flow set point or a set of first flow set points. The second flow set point value may correspond to a multiplication of the corresponding first set point value by a scalar value, such as a time-dependent value.

[0032] According to a preferred embodiment, the second flow setpoint value is a preferably time-dependent function of the reactant gas pressure measured in the reactant gas flow channel upstream of the mass flow control device or in the reactant gas generator.

[0033] According to a preferred embodiment, the second flow set point value is a preferably time-dependent function of a predicted availability of preferably low-carbon emission electricity as a function of time.

[0034] According to a preferred embodiment, the second flow setpoint value is a preferably time-dependent function of a predicted cost of energy varying over time.

[0035] According to a preferred embodiment, the respective function comprises a polynomial, preferably linear, dependence of the reaction gas pressure measured in the reaction gas flow channel upstream of the mass flow control device or in the reaction gas generator and / or of the predicted availability of electricity over time and / or of the predicted cost of energy over time, respectively.

[0036] According to a preferred embodiment, the primary gas or primary gas stream comprises mainly nitrogen or carbon dioxide.Preferably, it comprises an initial amount of oxygen which needs to be reduced or removed from the primary gas stream.

[0037] According to a preferred embodiment, the reactive gas stream mainly comprises hydrogen or carbon monoxide.

[0038] In the third aspect of the present disclosure, a method for controlling a system or device according to any of the embodiments of the first aspect or the second aspect is disclosed, the method comprising controlling a mass flow control device based on the inlet process conditions of the main gas flow and / or the outlet process conditions of the deoxygenated main gas flow so as to control the injection flow rate of the reaction gas injected into the main gas flow in the main gas flow channel to the required reaction gas flow rate.

[0039] According to a preferred embodiment, the method comprises calculating a required reactive gas flow rate to be injected into the primary gas flow based on the primary gas flow at the primary gas flow inlet, the oxygen concentration at the primary gas flow inlet and a required ratio of reactive gas concentration to oxygen concentration.

[0040] According to certain embodiments, the desired ratio of reactant gas concentration to oxygen concentration is constant.

[0041] According to a preferred embodiment, the desired ratio of the reactive gas concentration to the oxygen concentration depends on the target oxygen concentration of the deoxygenated primary gas stream.

[0042] According to a preferred embodiment, the desired ratio of the reactant gas concentration to the oxygen concentration depends on the flow load of the device.

[0043] According to a preferred embodiment, the method comprises calculating a required flow rate of reactive gas to be injected into the primary gas flow based on the actual oxygen concentration of the deoxygenated primary gas flow.

[0044] According to a preferred embodiment, the method comprises calculating a required reactant gas flow rate to be injected into the primary gas flow based on the actual reactant gas concentration of the deoxygenated primary gas flow.

[0045] According to a preferred embodiment, the method comprises calculating a required reactive gas flow rate to be injected into the primary gas flow based on the actual oxygen concentration of the deoxygenated primary gas flow and the actual reactive gas concentration.

[0046] According to a preferred embodiment, the method comprises providing at least periodically or continuously a first flow set point value for a desired flow of reactant gas to be injected to the mass flow control device.

[0047] According to a preferred embodiment, the method includes controlling the flow rate of the reactant gas entering the reactant gas flow channel from the reactant gas inlet.

[0048] According to a preferred embodiment, the method is applicable to a system or device comprising a reaction gas generator, and the method further comprises controlling the flow rate of the reaction gas generator.

[0049] Preferably, controlling the flow rate of the reaction gas generator comprises at least periodically or continuously providing a second flow rate set point value for the reaction gas flow to be generated to the reaction gas generator.

[0050] According to a preferred embodiment, the second flow set point value is a preferably time-dependent function, such as a polynomial function, of at least one first flow set point or a group of first flow set points.

[0051] The second flow set point value may be based on or derived from at least one first flow set point or a set of first flow set points. The second flow set point value may correspond to a multiplication of the corresponding first set point value by a scalar value, such as a time-dependent value.

[0052] According to a preferred embodiment, the second flow setpoint value is a preferably time-dependent function of the reactant gas pressure measured in the reactant gas flow channel upstream of the mass flow control device or in the reactant gas generator.

[0053] According to a preferred embodiment, the second flow set point value is a preferably time-dependent function of a predicted availability of preferably low-carbon emission electricity as a function of time.

[0054] According to a preferred embodiment, the second flow setpoint value is a preferably time-dependent function of a predicted cost of energy varying over time.

[0055] According to a preferred embodiment, the respective function comprises a polynomial, preferably a linear, dependence of the reaction gas pressure measured in the reaction gas flow channel upstream of the mass flow control device or in the reaction gas generator and / or of the predicted availability of electricity as a function of time and / or of the predicted cost of energy as a function of time.

[0056] As will be appreciated by those skilled in the art, the features and advantages disclosed for one of the above aspects of the present disclosure are implicitly disclosed for the other aspects, mutatis mutandis. In particular, aspects described for apparatus and system aspects may also be applicable and considered to disclose method aspects, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The present disclosure will be further clarified by the following description and accompanying drawings.

[0058] Figure 1 is a schematic overview of a system according to a preferred embodiment of the present disclosure.

[0059] Figure 2 is a schematic overview of feed-forward control of reactant gas flow according to a preferred embodiment of the present disclosure.

[0060] Figure 3 The relationship between the required ratio of the reaction gas concentration to the oxygen concentration and the oxygen concentration target according to the preferred embodiment of the present disclosure is shown.

[0061] Figure 4 The relationship between the required ratio of the reaction gas concentration to the oxygen concentration and the flow load of the device according to the preferred embodiment of the present disclosure is shown, wherein the maximum flow load of the device represents 100% load.

[0062] Figure 5 Feedback control of the reactant gas flow based on the oxygen concentration of the deoxygenated primary gas flow according to a preferred embodiment of the present disclosure is shown.

[0063] Figure 6 is a schematic overview of the feed-forward and feedback control of the reactant gas flow based on the oxygen concentration of the deoxygenated primary gas flow according to a preferred embodiment of the present disclosure.

[0064] Figure 7 is a schematic overview of feedback control of the reactant gas flow based on the reactant gas concentration of the deoxygenated primary gas flow according to a preferred embodiment of the present disclosure.

[0065] Figure 8is a schematic overview of the feed-forward and feedback control of the reactant gas flow based on the reactant gas concentration of the deoxygenated primary gas flow according to a preferred embodiment of the present disclosure.

[0066] Fig. 9 is a schematic overview of feedback control of the reactant gas flow based on the oxygen concentration of the deoxygenated primary gas flow and the reactant gas concentration of the deoxygenated primary gas flow according to a preferred embodiment of the present disclosure.

[0067] Fig.10 is a schematic overview of feed-forward and feedback control of the reactant gas flow using the oxygen concentration of the deoxygenated primary gas flow and the reactant gas concentration of the deoxygenated primary gas flow according to a preferred embodiment of the present disclosure.

[0068] Fig.11 The preferred embodiment of the present disclosure is shown in FIG. p Constant relationship with the reaction gas pressure.

[0069] Fig.12 The preferred embodiment of the present disclosure is shown in FIG. p Pressure band relationship with the reaction gas pressure.

[0070] Fig.13 The preferred embodiment of the present disclosure is shown in FIG. p Fine operating pressure band relationship with the reaction gas pressure.

[0071] Fig.14 The preferred embodiment of the present disclosure is shown in FIG. p S-shaped operating pressure band relationship with the reaction gas pressure. DETAILED DESCRIPTION

[0072] The present disclosure will be described with respect to specific embodiments and with reference to certain drawings, but the disclosure is not limited thereto but only by the claims. The drawings described are only schematic and non-restrictive. In the drawings, for illustrative purposes, the size of some elements may be exaggerated and not drawn to scale. The dimensions and relative dimensions do not necessarily correspond to actual reductions in practice of the present disclosure.

[0073] Furthermore, the terms first, second, third and the like used in the description and the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order.

[0074] Although referred to as "preferred," the various embodiments should be construed as examples in which the disclosure may be implemented, rather than limiting the scope of the disclosure.

[0075] Figure 1Preferred embodiments of an apparatus 1 and a system 9 for reducing the oxygen concentration in a primary gas or primary gas stream (or primary gas stream) 1000 are disclosed. The apparatus 1 comprises a primary gas stream channel 10 having a primary gas stream inlet 101 for the primary gas stream 1000 and a primary gas stream outlet 102 for a deoxygenated primary gas stream 1000*. It should be understood that the deoxygenated primary gas stream 1000* should be regarded as a primary gas stream having a lower oxygen content than the initial primary gas stream 1000, which may still contain a certain but at least reduced amount of oxygen, which depends on the actual situation and the intended use of the deoxygenated primary gas stream 1000* downstream of the apparatus 1 or system 9.

[0076] The device 1 comprises a reaction gas flow channel 20 for a reaction gas flow 2000, which comprises a reaction gas inlet 201 at a first end and is connected (preferably fluidly connected) to a main gas flow channel at a second end 202 (reaction gas outlet) at a connection location C, for example in order to allow injection of reaction gas into the main gas flow channel 10. The reaction gas flow channel 20 comprises a mass flow control device 21 for controlling the reaction gas flow, located downstream of the reaction gas inlet 201.

[0077] The device 1 comprises a reactor component 3 which is arranged in the main gas flow channel 10 downstream of the connection point C and upstream of the main gas flow outlet 102 .

[0078] The device 1 and the system 9 also include a control unit 4, which is suitable for controlling the mass flow control device 21 based on the inlet process conditions of the main gas flow 1000 and / or the outlet process conditions of the deoxygenated main gas flow 1000*, so as to control the injection flow rate of the reactant / reaction gas injected into the main gas flow 1000 in the main gas flow channel 10 to the required reaction gas flow rate.

[0079] Preferably, the system 9 further comprises a reaction gas generator 222, which is connected, preferably fluidly connected, to the reaction gas inlet 201, and the control unit 4 is further adapted to control the flow of the reaction gas generator 222. The system 9 may further comprise a reaction gas buffer 22, which is upstream of the reaction gas inlet 201 (and, for example, upstream of the mass flow control device 21) and downstream of the reaction gas generator 222. It should be noted that the reaction gas buffer 22 may be a dedicated buffer container, or simply the inner volume of a pipeline connecting the reaction gas generator 222 to the device 1 (e.g., to the reaction gas inlet 201 of the device).

[0080] The device 1 and the system 9 preferably comprise measuring means, such as sensors arranged at various locations.

[0081] For example, a pressure sensor S1 may be provided and arranged to measure the pressure of the reaction gas in or downstream of the reaction gas generator 222 (eg also upstream of the reaction gas inlet 201 , or upstream of the reaction gas buffer 22 ).

[0082] For example, at a position downstream of the main gas flow inlet 101 and upstream of the connection position C, an oxygen sensor S2 can be provided and arranged to measure the oxygen content of the main gas flow 1000, and / or a pressure sensor S3 can be provided and arranged to measure the pressure of the main gas flow 1000, or a flow measurement component (such as a flow meter or sensor S4) can be provided and arranged to measure the gas flow of the main gas flow 1000.

[0083] For example, an oxygen sensor S5 and / or a reactant sensor S6 may be provided and arranged to measure oxygen concentration and / or reactant gas concentration in the deoxygenated primary gas flow 1000 * downstream of the reactor component 3 and upstream of the primary gas flow outlet 102 .

[0084] Any of the above mentioned sensors is adapted to communicate the measured values ​​to the control member or unit 4 and the control unit 4 is configured and adapted to receive the measured values ​​from the sensors present among the respective sensors S1 to S6.

[0085] Whether one or more of the above mentioned sensors S1 to S6 need to be present in the device 1 or system 9 depends on the need for the respective measured values ​​in the method performed by the control unit 4, as the skilled person will appreciate and as will be further explained in the description.

[0086] An advantage of the embodiments of the present disclosure is that the reactive gas can be used more efficiently and overuse can be avoided. In addition, it is expected that the performance and life of the associated reactive gas generator 222 will be improved.

[0087] An objective of embodiments of the present disclosure is to calculate the amount of reactive gas required to deoxygenate the main gas stream 1000 based on multiple process conditions to consistently match deoxygenation requirements, reduce reactive gas consumption, and efficiently operate the reactive gas source based on the calculated values.

[0088] For example, this provides the following advantages:

[0089] 1. Ensure that Device 1 continues to meet export requirements;

[0090] 2. Reaction gas consumption is minimized;

[0091] 3. The reaction gas generator 222 is operated efficiently.

[0092] In a preferred embodiment, the reaction gas is hydrogen or carbon monoxide. In the former case, the required amount of reaction gas can be conveyed to a reaction gas generator 222, which is implemented as a hydrogen generator, in a preferred embodiment an electrolyzer.

[0093] The operation and control of the gas used for deoxygenation relies on a central controller 4 which communicates a flow set point to a mass flow control device 21 which injects a corresponding amount of the reactant gas flow in the main gas stream 1000. The flow set point is calculated based on the inlet and / or outlet process conditions sensed by appropriate means, as explained in subsequent paragraphs.

[0094] In addition, the central controller 4 preferably transmits a generator set point corresponding to the flow rate of the reactant gas that must be generated by the reactant gas generator 222. This set point is directly related to the flow rate set point and depends, among other things, on the reactant gas process conditions. This operation is described in more detail in the following paragraphs.

[0095] A. Control of Reaction Gas Flow in the Deoxygenation Unit

[0096] Control of the flow set point (i.e., the reactive gas flow target transmitted to the mass flow control device 21 and possibly used to calculate the generator set point if the reactive gas generator 222 is available) is based on the inlet process conditions of the primary gas stream 1000 and / or the outlet process conditions of the deoxygenated primary gas stream 1000*. The following control scheme is proposed.

[0097] 1. Control the flow set point based on feed-forward control.

[0098] In the feedforward control scheme, the required amount of reactant gas is continuously calculated based on the inlet process conditions of the main gas flow 1000, more specifically the main gas flow 1000 at the main gas flow inlet 101, the oxygen concentration at the main gas flow inlet 101, and the required ratio of the reactant gas concentration to the oxygen concentration. Figure 2 , where the calculated value of the reaction gas flow rate labeled “Reaction Gas Flow Target” represents the flow set point and is subsequently transmitted to the mass flow control device 21.

[0099] It should be noted that for the oxygen concentration at the main gas inlet 101, the maximum inlet O 2 The concentration parameter is used to add a maximum limit. Similarly, the reaction gas flow target is limited by the minimum reaction gas flow parameter. These two conditions are not mandatory in the entire control system.

[0100] The desired ratio of reactant gas concentration to oxygen concentration enables adjustment of the reactant gas flow target based on the following method.

[0101] o In a first feed-forward control scheme, a desired ratio of reactant gas concentration to oxygen concentration is maintained at a fixed value, which may be a stoichiometric coefficient in the reaction between the reactant gas and oxygen.

[0102] o In another control scheme, the desired ratio of reactant gas concentration to oxygen concentration depends on the target oxygen concentration of the deoxygenated primary gas stream 1000*.

[0103] Figure 3 A trend is depicted in which the lower the oxygen concentration target of the deoxygenated primary gas stream 1000 *, the higher the required ratio of the deoxygenated primary gas stream 1000 *.

[0104] o Another variant for adjusting the desired ratio of the reaction gas concentration to the oxygen concentration depends on the flow load of the device 1. It is well known that the technical limitations of the flow sensing device lead to measurement deviations in the low flow area. These deviations can be compensated via the desired ratio of the reaction gas concentration to the oxygen concentration.

[0105] As an example, Figure 4 A trend is depicted that the lower the flow load of the device 1, the higher the required ratio of the reaction gas concentration to the oxygen concentration.

[0106] o In yet another feed-forward control scheme, both the oxygen concentration target and the flow load of the device 1 can be combined for a compound adjustment of the desired ratio of reactant gas concentration to oxygen concentration.

[0107] 2. Control the flow set point based on feedback control using the actual oxygen concentration of the deoxygenated primary gas stream.

[0108] In this feedback control scheme, the actual oxygen concentration of the deoxygenated primary gas flow is used in the control of the reaction gas flow. This means that the controller unit 4 is able to provide feedback control in the form of PID control or its variants (P, PI, ...).

[0109] exist Figure 5 The control scheme is depicted in the block diagram of , where the calculated value of the reactant gas flow rate, labeled “reactant gas flow rate target”, represents the flow rate set point and is subsequently transmitted to the mass flow control device 21.

[0110] The baseline value (variable γ) is used to minimize the reaction gas consumption, since this value will be systematically corrected by errors in the oxygen concentration of the deoxygenated primary gas flow. γ may depend on the nominal flow of the device 1, or may be equal to the minimum reaction gas flow, for example.

[0111] Multiply the error in the oxygen concentration of the deoxygenated main gas flow by the total outlet gas flow, which is the sum of the main gas flow at the main gas flow inlet and the injected reactive gas flow. This multiplication should account for the total outlet gas flow only. For some applications, the reactive gas flow can be neglected since it is significantly smaller than the main gas flow.

[0112] This feedback scheme directly relates the reactant gas flow rate to the desired output of the device 1. In addition, the feedback scheme ensures that the device 1 continues to meet its outlet requirements by correcting for inaccuracies in the sensing and actuation devices used in the control scheme.

[0113] 3. Control the flow set point based on feed-forward and feedback control using the actual oxygen concentration of the deoxygenated primary gas stream.

[0114] exist Figure 6 The depicted control scheme combines a feed-forward control scheme with a feedback control scheme by using the feed-forward signal as a baseline and correcting for errors in the oxygen concentration in the deoxygenated primary gas flow.

[0115] It should be noted that all the alternatives presented in the control of the flow settings based on feedforward control can be used to adjust the desired ratio of reactant gas concentration to oxygen concentration.

[0116] This feedback scheme allows for faster startup and faster response to load changes because the baseline is directly related to the primary gas flow. In addition, the feedback scheme also directly relates the reactant gas flow to the desired output of the device 1, which allows correction of inaccuracies in the sensing and actuating devices used in the control scheme.

[0117] 4. Control the flow set point based on feedback control of the actual reactant gas concentration using the deoxygenated primary gas stream.

[0118] exist Figure 7 The feedback control scheme depicted uses the actual reactant gas concentration of the deoxygenated primary gas stream in controlling the reactant gas flow rate.

[0119] The baseline value (variable γ) is used to minimize the reaction gas consumption, because this value will be systematically corrected by the error in the oxygen concentration of the deoxygenated main gas flow. γ may depend on the nominal flow rate of the device 1, or may be equal to the minimum reaction gas flow rate, for example. However, the outlet reaction gas concentration target should be high enough to ensure complete deoxygenation.

[0120] This control scheme is of particular interest in cases where the reactive gases appear to be detrimental to the process using a deoxygenated primary gas stream.

[0121] 5. Control the flow set point based on feed forward and feedback control of the actual reactant gas concentration using the deoxygenated primary gas stream.

[0122] exist Figure 8 The following control scheme depicted combines a feed-forward control scheme with a feedback control scheme by using the feed-forward signal as a baseline and correcting for errors in the reactant gas concentration of the deoxygenated primary gas flow.

[0123] It should be noted that all the alternatives presented in the control of the flow set point based on feedforward control can be used to adjust the desired ratio of reactant gas concentration to oxygen concentration.

[0124] This feedback scheme allows for faster startup and faster response to load changes because the reactant gas flow is directly related to the desired output of the device 1 .

[0125] This control scheme is of particular interest in cases where the reactive gases appear to be detrimental to the process using a deoxygenated primary gas stream.

[0126] 6. Control the flow set point based on feedback control using the actual oxygen concentration of the deoxygenated primary gas stream and the actual reactant gas concentration.

[0127] exist Fig. 9 The feedback control scheme depicted uses the actual oxygen concentration of the deoxygenated main gas flow and the actual reactant gas concentration in the control of the reactant gas flow.

[0128] The baseline flow value γ is thereby corrected by the less stringent outlet requirements of the device 1 .

[0129] 7. Control the flow set point based on feed forward and feedback control using the actual oxygen concentration of the deoxygenated primary gas stream and the actual reactant gas concentration.

[0130] exist Fig.10 In this further embodiment depicted, a feed-forward scheme is combined with a feedback control scheme using both the actual oxygen concentration of the deoxygenated primary gas stream and the actual reactant gas concentration.

[0131] This control scheme is of particular interest in cases where the reactive gases appear to be detrimental to the process using a deoxygenated primary gas stream.

[0132] B. Control of the operation of the reaction gas generator

[0133] The operation of the reactant gas generator may be determined by the generator set point transmitted to the reactant gas generator at each time frame according to the following equation:

[0134] Generator set point (t)

[0135] =g(flow set point (t), time range)*c p (t)*c e (t)*cc (t)

[0136] Therefore, the generator set point is calculated by dividing the function g by the pressure coefficient c p , emission coefficient c e and cost coefficient c c The function g is a time dependent quantity calculated by multiplying the flow set point and the time range to provide a baseline flow target for the reactant gas generator.

[0137] It should be noted that c p (t), c e (t) or c c One or both of (t) may be equal to 1; in other words, the generator set point equation may depend only on the value selected from c p (t), c e (t) and c c (t) is a set of one or two parameters.

[0138] The generator set point should reflect the desired flow rate to be generated by the reactant gas generator 222. If the desired amount expected by the reactant gas generator 222 is a value other than the flow rate, additional calculations should convert the calculated flow rate to the desired amount. The desired amount may be a percentage of the reactant gas generator's nominal flow rate, a current equivalent to the flow rate, etc.

[0139] • The function g depends on the flow set point (t) and the time range. The flow set point (t) is calculated continuously by the control unit 4 using one of the schemes presented in the previous section. The time range is a time value representing the period in the past to be looked at.

[0140] Thus, the function g performs an algebraic operation on the time-dependent flow setpoint over a time horizon. Several operations are proposed, for example:

[0141] Og(flow set point (t), time range) = maximum value (flow set point (t - time range, ..., flow set point (t)), i.e., the maximum consumption over the last time range.

[0142] Og(flow setpoint(t), time frame) = average(flow setpoint(t-time frame, ..., flow setpoint(t)), i.e., the average consumption over the last time frame.

[0143] Og(flow setpoint(t), time horizon) = flow setpoint'(t)*t, ie consumption based on the instantaneous time derivative of consumption.

[0144] Og(flow setpoint(t), time horizon) = flow setpoint(t), ie the instantaneous consumption evaluated at each time horizon.

[0145] ●Pressure coefficient c p is calculated based on the reaction gas process conditions, more specifically the reaction gas pressure downstream of the reaction gas generator (e.g., in the reaction gas buffer) at time t. p For the calculation of , several options are proposed.

[0146] It should be noted that pressure limitation of the reactant gas generator 222 can stop its operation within its own pressure operating range, which is independent of the generator set point and therefore independent of c p In this case, these pressure limits become the decisive pressures and pressures beyond these pressure limits have an effect on c p Every adjustment is invalid.

[0147] o The first example of an operational strategy makes c p remains constant at the value α. Therefore, the generator set point is p Zoom. This Fig.11 As shown in the figure.

[0148] o Fig.12 The second example of the operating strategy shown in FIG. 4 introduces the control of c based on the pressure parameters defined in the control unit 4. p More precisely, a pressure band is introduced, which is determined by the starting pressure p in the control unit 4. 启动 and stop pressure p 停止 Limited. 启动 can be equal to a fixed value, but should be higher than the pressure of the main gas stream at the main gas stream inlet to ensure proper injection of the reaction gas into the main gas stream. 启动 can be defined as p 入口主气体 +δ, where δ represents a freely selectable pressure value. 停止 It may be equal to the maximum pressure at which the reaction gas generator 222 can generate the reaction gas.

[0149] When the reaction gas pressure downstream of the reaction gas generator 222 (in the reaction gas buffer 22) is equal to the starting pressure, c p =α.

[0150] When the reaction gas pressure in the reaction gas buffer 22 reaches the stop pressure, c p =0, and the reaction gas generator 222 stops generating the reaction gas until the reaction gas is consumed by the device 1.

[0151] oThe third example of an operating strategy introduces the use of operating pressure p 运行 The pressure of the reaction gas in the reaction gas buffer 22 is preferably maintained at the operating pressure. 运行Can be equal to the center of pressure The pressure band now surrounds p 运行 Separated by intervals of similar length. Fig.13 Four intervals are provided in the depicted example diagram.

[0152] This means that c p becomes strongly dependent on the pressure of the reactant gas. p The maximum value of is set to the variable value β which can be selected. The number of steps and the width of the steps (pressure range) can also be selected and controlled by the additional parameter c p Quantify.

[0153] o Another option is c p In this case, the pressure coefficient is expressed as Fig.14 The sigmoid function shown.

[0154] This expression c p The benefit is that the pressure corrects more strongly towards the operating pressure at the edge of the pressure band. This can be more effective in the event of fluctuating reaction gas demand.

[0155] ●Emission coefficient c e represents the CO associated with the power available for operation of the reaction gas generator 222 at time t 2 If low-carbon electricity is available, this results in an emissions factor greater than one, and vice versa.

[0156] The availability of low carbon electricity may be assessed based on eg renewable energy forecasts.This step may eg be performed in the control unit 4 which may eg be connected to a database or information source eg on the internet.

[0157] ●The cost coefficient c at time t c Directly related to the cost of kWh of energy. If low cost electricity is available, this results in a cost factor greater than one and vice versa.

[0158] The evaluation of the electricity costs may be done based on actual costs or based on expected energy costs and expected consumption.This step may be performed, for example, in the control unit 4, which may for example be connected to a database or information source, for example on the Internet.

[0159] One or more of the following objectives are thereby achieved.

[0160] 1. By keeping the pressure of the reaction gas in the reaction gas buffer at p 启动 With p 停止The number of starts and stops of the reaction gas generator 222 is reduced by operating in the operating pressure band between 20 and 25, which increases the life of the reaction gas generator 222. This is achieved by adjusting the reaction gas consumption of the device 1 (i.e., the flow set point) and by adjusting the pressure of the reaction gas generator 222 to a certain value. p This is achieved by changing the generator set point to correct the pressure;

[0161] 2. Reduce operating costs and / or CO by producing reactant gases based on the availability of low-cost electricity and low-carbon electricity, respectively 2 emission;

[0162] 3. The pressure of the reactant gas is more stable, resulting in more accurate injection and ensuring lower design pressures for components due to selectable operating pressures.

[0163] It should be noted that in the case of the pressure regulating reaction gas generator 222, c p The values ​​of and function g may loose their values ​​because all regulation is achieved by the pressure value of the reaction gas generator 222 rather than the reaction gas flow target. In this case, the emission coefficient c e and cost coefficient c c Still valid.

Claims

1. A device (1) for reducing the oxygen concentration in a primary gas flow (1000), the device comprising a. a main gas flow channel (10), the main gas flow channel having a main gas flow inlet (101) for the main gas flow (1000) and a main gas flow outlet (102) for the deoxygenated main gas flow (1000*); b. a reaction gas flow channel (20), the reaction gas flow channel comprising a reaction gas inlet (201) for a reaction gas flow (2000) at a first end and connected to the main gas flow channel (10) at a second end (202) at a connection position (C) so as to allow injection of reaction gas into the main gas flow channel (10), the reaction gas flow channel (20) comprising a mass flow control device (21) downstream of the reaction gas inlet (201); c. a reactor member (3), said reactor member being arranged in said main gas flow channel (10) downstream of said connection position (C) and upstream of said main gas flow outlet (102); d. A control unit (4), which is suitable for controlling the mass flow control device (21) based on the inlet process conditions of the main gas flow (1000) and / or the outlet process conditions of the deoxygenated main gas flow (1000*), so as to control the injection flow rate of the reaction gas injected into the main gas flow (1000) in the main gas flow channel (10) to the required reaction gas flow rate.

2. An apparatus according to claim 1, wherein the control unit (4) is suitable for calculating the required reaction gas flow rate to be injected into the main gas flow (1000) based on the main gas flow (1000) at the main gas flow inlet (101), the oxygen concentration at the main gas flow inlet (101) and the required ratio of reaction gas concentration to oxygen concentration.

3. The apparatus of claim 2, wherein the desired ratio of reactant gas concentration to oxygen concentration is constant.

4. The apparatus of claim 2, wherein the desired ratio of reactive gas concentration to oxygen concentration depends on a target oxygen concentration of the deoxygenated primary gas flow (1000*).

5. The device according to claim 2 or 4, wherein the desired ratio of reaction gas concentration to oxygen concentration depends on the flow load of the device (1).

6. An apparatus according to any one of the preceding claims 1 to 4, wherein the control unit (4) is adapted to calculate the required reaction gas flow rate to be injected into the main gas flow (1000) based on the actual oxygen concentration of the deoxygenated main gas flow (1000*).

7. An apparatus according to any one of the preceding claims 1 to 4, wherein the control unit (4) is adapted to calculate the required reaction gas flow rate to be injected into the main gas flow (1000) based on the actual reaction gas concentration of the deoxygenated main gas flow (1000*).

8. An apparatus according to any one of the preceding claims 1 to 4, wherein the control unit (4) is adapted to calculate the required reaction gas flow rate to be injected into the main gas flow (1000) based on the actual oxygen concentration and the actual reaction gas concentration of the deoxygenated main gas flow (1000*).

9. The device according to any one of the preceding claims 1 to 4, wherein controlling the mass flow control device (21) by the control unit (4) comprises at least periodically or continuously providing a first flow set point value for the desired reaction gas flow to be injected to the mass flow control device (21).

10. The device according to any one of the preceding claims 1 to 4, wherein the control unit (4) is further adapted to control the flow rate of the reaction gas entering the reaction gas flow channel (20) from the reaction gas inlet (201).

11. A system (9) for reducing the oxygen concentration in a main gas flow (1000), the system comprising a device (1) according to any of the preceding claims, the system also comprising a reaction gas generator (222) connected to, preferably fluidically connected to, the reaction gas inlet (201) and a reaction gas buffer (22) optionally arranged downstream of the reaction gas generator (222) and upstream of the reaction gas inlet (201), wherein the control unit (4) is also suitable for controlling the flow rate of the reaction gas generator (222).

12. The system of claim 11, wherein controlling the flow rate of the reaction gas generator (222) comprises at least periodically or continuously providing a second flow rate set point value for the reaction gas flow (2000) to be generated to the reaction gas generator (222).

13. System according to claim 12, wherein the system (9) comprises an apparatus (1) according to claim 9, wherein the second flow set point value is a preferably time-dependent function of at least one first flow set point or a group of said first flow set points.

14. A system according to claim 12 or 13, wherein the second flow set point value is a preferably time-dependent function of the reaction gas pressure measured in the reaction gas flow channel (20) upstream of the mass flow control device (21) or in the reaction gas generator (222).

15. A system according to claim 12 or 13, wherein the second flow set point value is a preferably time-dependent function of the predicted availability of preferably low carbon emission electricity as a function of time.

16. A system according to claim 12 or 13, wherein the second flow set point value is a preferably time-dependent function of a predicted cost of energy that varies over time.

17. A system according to claim 14, wherein the corresponding functions respectively include polynomial correlations, such as linear correlations, of the reaction gas pressure measured in the reaction gas flow channel (20) upstream of the mass flow control device (21) or in the reaction gas generator (222) and / or the predicted availability of electricity over time and / or the predicted cost of energy over time.

18. The system according to any of the preceding claims 11 to 13, wherein the primary gas flow (1000) mainly comprises nitrogen or carbon dioxide.

19. The system according to any of the preceding claims 11 to 13, wherein the reaction gas stream (2000) mainly comprises hydrogen or carbon monoxide.

20. A method for controlling an apparatus (1) or system (9) according to any one of the preceding claims, comprising controlling the mass flow control device (21) based on the inlet process conditions of the main gas flow (1000) and / or the outlet process conditions of the deoxygenated main gas flow (1000*) so as to control the injection flow rate of the reaction gas injected into the main gas flow (1000) in the main gas flow channel (10) to a desired reaction gas flow rate.

21. The method according to claim 20 comprises calculating a required reaction gas flow rate to be injected into the main gas flow (1000) based on the main gas flow (1000) at the main gas flow inlet (101), the oxygen concentration at the main gas flow inlet (101) and the required ratio of reaction gas concentration to oxygen concentration.

22. The method of claim 21, wherein the desired ratio of reactant gas concentration to oxygen concentration is constant.

23. The method of claim 21, wherein the desired ratio of reactant gas concentration to oxygen concentration depends on a target oxygen concentration of the deoxygenated primary gas stream (1000*).

24. A method according to claim 21 or 23, wherein the desired ratio of reaction gas concentration to oxygen concentration depends on the flow load of the device (1).

25. The method according to any one of claims 20 to 23, comprising calculating a required flow rate of reactive gas to be injected into the primary gas flow (1000) based on the actual oxygen concentration of the deoxygenated primary gas flow (1000*).

26. The method according to any of the preceding claims 20 to 23, comprising calculating a required reactive gas flow rate to be injected into the primary gas flow (1000) based on the actual reactive gas concentration of the deoxygenated primary gas flow (1000*).

27. The method according to any of the preceding claims 20 to 23, comprising calculating a required reaction gas flow rate to be injected into the main gas flow (1000) based on the actual oxygen concentration and the actual reaction gas concentration of the deoxygenated main gas flow (1000*).

28. The method according to any of the preceding claims 20 to 23, comprising providing at least periodically or continuously a first flow set point value for the desired reaction gas flow rate to be injected to the mass flow control device (21).

29. The method according to any one of the preceding claims 20 to 23, further comprising controlling a flow rate of the reaction gas entering the reaction gas flow channel (20) from the reaction gas inlet (201).

30. The method according to claim 29, for controlling the system (9) or the device (1) comprising a reaction gas generator (222), the method further comprising controlling the flow rate of the reaction gas generator (222).

31. The method of claim 30, wherein controlling the flow rate of the reaction gas generator (222) comprises at least periodically or continuously providing a second flow rate set point value for the reaction gas flow (2000) to be generated to the reaction gas generator (222).

32. The method of claim 28, wherein the second flow set point value is a preferably time-dependent function of at least one first flow set point or a group of said first flow set points.

33. A method according to claim 31, wherein the second flow set point value is a preferably time-dependent function of the reaction gas pressure measured in the reaction gas flow channel (20) upstream of the mass flow control device (21) or in the reaction gas generator (222).

34. The method of claim 31 , wherein the second flow set point value is a preferably time-dependent function of a predicted availability of preferably low carbon emission electricity that varies over time.

35. The method of claim 31 , wherein the second flow set point value is a preferably time-dependent function of a predicted cost of energy that varies over time.

36. A method according to claim 33, wherein the corresponding function respectively includes a polynomial correlation, preferably a linear correlation, of the reaction gas pressure measured in the reaction gas flow channel upstream of the mass flow control device (21) or in the reaction gas generator (222) and / or the predicted availability of electricity over time and / or the predicted cost of energy over time.

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