The present disclosure generally relates to systems and methods for hydrocarbon dehydrogenation. More specifically, the present disclosure relates to systems and methods for hydrocarbon dehydrogenation that include a control mechanism for switching one or more dehydrogenation reactors between a dehydrogenation mode and a regeneration mode based on temperatures in catalyst beds.
Hydrocarbon dehydrogenation is a process used for producing a variety of alkene products. Examples of these alkene products include isobutylene used for producing methyl tert-butyl ether (MTBE) and propylene used for polypropylene production. Currently, most commercially available alkane dehydrogenation technologies, including Süd-Chemie CATOFIN® process, CATADIENE® process, UOP's Oleflex® process, Phillips' Star™ process, and the Snamprogetti-Yarsintez process, use fixed bed or fluidized bed reactors with various types of catalysts.
These hydrocarbon dehydrogenation units usually include multiple reactors containing catalyst beds therein. During the dehydrogenation process, each of the reactors are operated in cycles, each of which includes a dehydrogenation step, a catalyst regeneration step, a long evacuation/reduction step, and a steam purge-short evacuation step. Conventionally, the operation sequence for each of the reactors, including the timing and duration of each of the steps, is determined based on predicted catalyst activities, safety requirements, and mechanical properties of the reactors. However, the overall productivity of the hydrocarbon dehydrogenation units is generally not taken into consideration when the operation sequence is determined, resulting in loss of productivity of the hydrocarbon dehydrogenation units.
Overall, while systems and methods for dehydrogenating hydrocarbons exist, the need for improvements in this field persists in light of at least the aforementioned drawback of the conventional systems and methods.
A solution to at least the above mentioned problem associated with the systems and methods for dehydrogenating hydrocarbons is discovered. The solution resides in a system and method for dehydrogenating hydrocarbons that includes a control mechanism at least partially based on productivity of the hydrocarbon dehydrogenation units in the system, thereby increasing the overall productivity and reducing the production costs for dehydrogenated hydrocarbon. Additionally, the disclosed methods and systems include measuring temperatures in the catalyst bed as the variable to represent the state of operation for the reactors to determine the operation sequence. This can be beneficial for avoiding any complicated procedure to obtain required measurements to determine how the reactors are operating, resulting in low capital expenditure and ease of implementation for the disclosed methods. Therefore, the systems and methods of the present disclosure provide a technical solution to the problem associated with the conventional systems and methods for dehydrogenating hydrocarbons.
Embodiments of the disclosure include a method of dehydrogenating a hydrocarbon. The method comprises initiating a dehydrogenation mode for a reactor to dehydrogenate the hydrocarbon. The method comprises detecting a temperature in a catalyst bed of the reactor during the dehydrogenation mode. The method comprises calculating mathematical time-derivatives of the detected temperature. The method comprises switching the reactor from the dehydrogenation mode to a regeneration mode to regenerate the catalyst of the catalyst bed, in response to an absolute value of the mathematical time-derivative of the detected temperature in the catalyst bed being less than a critical value.
Embodiments of the disclosure include a method of operating a fixed bed reactor for dehydrogenating a hydrocarbon. The method comprises initiating a dehydrogenation mode for the fixed bed reactor to dehydrogenate the hydrocarbon to produce a dehydrogenated hydrocarbon. The method comprises detecting a first temperature of a top portion of a catalyst bed and detecting a second temperature of a bottom portion of the catalyst bed of the fixed bed reactor. The method comprises calculating mathematical time-derivatives of the detected first temperature and mathematical time-derivatives of the detected second temperature. The method comprises switching the fixed bed reactor from the dehydrogenation mode to a regeneration mode to regenerate the catalyst bed, in response to (a) an absolute value of the mathematical time-derivative of the detected first temperature being less than a first critical value and/or (b) an absolute value of the mathematical time-derivative of the detected second temperature being less than a second critical value. The method comprises switching the fixed bed reactor from the regeneration mode to the dehydrogenation mode in response to (c) an absolute value of the mathematical time-derivative of the detected first temperature being less than a third critical value and/or (d) an absolute value of the mathematical time-derivative of the detected second temperature being less than a fourth critical value.
Embodiments of the disclosure include a method of operating a reaction unit comprising one or more fixed bed reactors for dehydrogenating a hydrocarbon. The method comprises providing a programmable logic controller (PLC). The PLC comprises (i) a memory, (ii) a database stored in the memory, the database comprising a first critical value, a second critical value, a third critical value and a fourth critical value, and (iii) one or more processors communicatively coupled to the memory, the one or more processors configured to switch each of the one or more fixed bed reactors between a dehydrogenation mode and a regeneration mode based on the first critical value, the second critical value, the third critical value, and the fourth critical value. The method comprises initiating, by the PLC, a dehydrogenation mode for one or more of the fixed bed reactors to dehydrogenate the hydrocarbon to produce a dehydrogenated hydrocarbon. The method comprises continuously detecting a first temperature of a top portion a catalyst bed of each of the fixed bed reactors. The method comprises continuously detecting a second temperature of a bottom portion of the catalyst bed of each of the fixed bed reactors. The method comprises continuously calculating, by the PLC, mathematical time-derivatives of the detected first temperature and the detected second temperature for each of the fixed bed reactors. The method comprises switching, via the PLC, one or more of the fixed bed reactors from the dehydrogenation mode to a regeneration mode to regenerate the catalyst bed of each of the fixed bed reactors, in response to (a) an absolute value of the mathematical time-derivative of the detected first temperature being less than a first critical value and/or (b) an absolute value of the mathematical time-derivative of the detected second temperature being less than a second critical value. The method comprises switching, via the PLC, one or more of the fixed bed reactors from the regeneration mode to the dehydrogenation mode, in response to (c) an absolute value of the mathematical time-derivative of the detected first temperature being less than a third critical value and/or (d) an absolute value of the mathematical time-derivative of the detected second temperature being less than a fourth critical value.
The following includes definitions of various terms and phrases used throughout this specification.
The terms “about” or “approximately” are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment the terms are defined to be within 10%, preferably, within 5%, more preferably, within 1%, and most preferably, within 0.5%.
The terms “wt. %”, “vol. %” or “mol. %” refer to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume, or the total moles of material that includes the component. In a non-limiting example, 10 moles of component in 100 moles of material is 10 mol. % of component.
The term “substantially” and its variations are defined to include ranges within 10%, within 5%, within 1%, or within 0.5%.
The terms “inhibiting” or “reducing” or “preventing” or “avoiding” or any variation of these terms, when used in the claims and/or the specification, include any measurable decrease or complete inhibition to achieve a desired result.
The term “effective,” as that term is used in the specification and/or claims, means adequate to accomplish a desired, expected, or intended result.
The use of the words “a” or “an” when used in conjunction with the term “comprising,” “including,” “containing,” or “having” in the claims or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”
The words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.
The process of the present disclosure can “comprise,” “consist essentially of,” or “consist of” particular ingredients, components, compositions, etc., disclosed throughout the specification.
The term “primarily,” as that term is used in the specification and/or claims, means greater than any of 50 wt. %, 50 mol. %, and 50 vol. %. For example, “primarily” may include 50.1 wt. % to 100 wt. % and all values and ranges there between, 50.1 mol. % to 100 mol. % and all values and ranges there between, or 50.1 vol. % to 100 vol. % and all values and ranges there between.
Other objects, features and advantages of the present disclosure will become apparent from the following figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific embodiments of the disclosure, are given by way of illustration only and are not meant to be limiting. Additionally, it is contemplated that changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.
For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
Currently, the operation sequence (e.g., for timing and duration for dehydrogenation and regeneration steps) for reactors in a hydrocarbon dehydrogenation system is determined based on catalyst activity and safety specifications without considering overall productivity of the reactors, resulting in low productivity and increased production cost for dehydrogenated hydrocarbons. The present disclosure provides a solution to at least this problem. The solution is premised on a method of dehydrogenating hydrocarbons where the reactors are sequenced based on productivity of the reactors such that the productivity of dehydrogenated hydrocarbon is optimized. Furthermore, the disclosed method uses temperatures in the catalyst beds of the reactors as an indication of productivity, thereby simplifying the steps to implement the methods in the dehydrogenation unit. These and other non-limiting aspects of the present disclosure are discussed in further detail in the following sections.
In embodiments of the disclosure, the system for dehydrogenating hydrocarbons includes one or more reactors and a control unit configured to control the sequence of the one or more reactors. With reference to
According to embodiments of the disclosure, system 100 includes a reaction unit comprising one or more dehydrogenation reactors (e.g., reactor 101, reactor 102, and reactor 103) configured to dehydrogenate a hydrocarbon. Non-limiting examples of the hydrocarbon can include isobutane, n-butane, propane, ethane, methane, and combinations thereof. In embodiments of the disclosure, the dehydrogenation reactors are fixed bed reactors and each of the dehydrogenation reactors comprises a catalyst bed. In embodiments of the disclosure, the reaction unit is configured to dehydrogenate isobutane and the reaction unit comprises 3-5 fixed bed reactors operated in parallel. In embodiments of the disclosure, the reaction unit comprises 6-12 fixed bed reactors operated in parallel. In embodiments of the disclosure, the catalyst comprises oxides or carbides of Al, Si, Ti, Zr, Zn, Ce, Sn, Mg, Ca, La, Cr, Cs, Ba, and combinations thereof. The catalyst may include Cr/Al (chromium oxide over alumina), Sn-Pt/Al (tin-platinum over alumina), or combinations thereof. Each of the reactors is configured to operate in a dehydrogenation mode, a regeneration mode, and a purging mode, according to embodiments of the disclosure.
In the dehydrogenation mode, the inlet of each of the reactors, in embodiments of disclosure, is in fluid communication with a heater 110 (which is configured to heat a hydrocarbon feed stream 13 to a reaction temperature), and the outlet of the reactors, in embodiments of the disclosure, is in fluid communication with a heat exchanger 108 (which is configured to cool a reaction effluent stream 14 coming from the reactors). In embodiments of the disclosure, system 100 comprises a compression and recovery system 109 configured to compress and separate reaction effluent stream 14 to produce a recycle stream 12 comprising unreacted hydrocarbon, and a product stream 17 comprising the dehydrogenated hydrocarbon. Recycle stream 12 and a fresh feed stream 11 comprising the hydrocarbon can be combined to form hydrocarbon feed stream 13.
System 100 may further include a regeneration air system comprising an air compressor 104 configured to blow an air stream 15 into the reactor in the regeneration mode. According to embodiments of the disclosure, a regeneration air heater 105 is configured to heat air stream 15 from air compressor 104. System 100 can comprise a fuel injector 106 configured to inject fuel gas into the reactor in the regeneration mode. System 100 can further comprise a heat exchanger 107 configured to cool down a regeneration effluent stream 16 from the reactor in the regeneration mode or in the purging mode.
According to embodiments of the disclosure, system 100 comprises a control system configured to control operating parameters of the reactors. The control system can include a plurality of temperature sensors configured to obtain temperature readings at one or more locations of the catalyst bed of each reactor, and a programmable logic controller (PLC) 120 configured to determine the sequence of the reactors, including timing and duration of the regeneration mode, the dehydrogenation mode, and/or the purging mode. In embodiments of the disclosure, PLC 120 is configured to determine the sequence of the reactors based on the temperature readings. In embodiments of the disclosure, the temperature sensors are configured to detect temperature on a top portion and a bottom portion of a catalyst bed of a reactor. The top portion of the catalyst bed is the upper half of the catalyst bed of each reactor. In embodiments of the disclosure, the top portion of the catalyst bed is a portion from top of the catalyst bed to 15 to 22% depth of the catalyst bed. The bottom portion of the catalyst bed is the lower half of the catalyst bed of each reactor. In embodiments of the disclosure, the bottom portion is a bottom 10% to 20% depth of the catalyst bed. In embodiments of the disclosure, the depth of the catalyst bed for each reactor is about 190 cm, and the top portion of the catalyst bed is the region from the top of the catalyst bed to 30 cm in the catalyst bed below the top of the catalyst bed, and the bottom portion of the catalyst bed includes 160 cm from the top of the catalyst bed to the bottom of the catalyst bed. In embodiments of the disclosure, the PLC 120 can include a proportional-integral-derivative (PID) controller.
In embodiments of the disclosure, PLC 120 can include a memory and a database stored in the memory. In embodiments of the disclosure, the database comprises a first critical value, a second critical value, a third critical value, and fourth critical value. In embodiments of the disclosure, PLC 120 comprises one or more processors communicatively coupled to the memory, the one or more processors configured to switch each of the fixed bed reactors between the dehydrogenation mode and the regeneration mode based on the first critical value, the second critical value, the third critical value, and fourth critical value. In embodiments of the disclosure, PLC 120 comprises a non-transitory storage medium having instructions for switching each of the fixed bed reactors between the dehydrogenation mode and the regeneration mode based on one or more of the first critical value, the second critical value, the third critical value, and fourth critical value.
According to embodiments of the disclosure, PLC 120 is configured to control each of the one or more fixed bed reactors independently. According to embodiments of the disclosure, the control system is configured to, via the temperature sensors, continuously, intermittently, or periodically detect a first temperature of a top portion of a catalyst bed of each of the reactors and continuously, intermittently, or periodically detect a second temperature of a bottom portion of the catalyst bed of each of the reactors during the dehydrogenation mode. The control system may be configured to detect the first temperature and/or the second temperature continuously or intermittently with an interval of 1 second to 10 minutes and all ranges and values there between including a ranges of 1 second to 10 seconds, 10 seconds to 20 seconds, 20 seconds to 30 seconds, 30 seconds to 40 seconds, 40 seconds to 50 seconds, 50 seconds to 1 minute, 1 minute, to 2 minute, 2 minutes to 3 minutes, 3 minutes to 4 minutes, 4 minutes to 5 minutes, 5 minutes to 6 minutes, 6 minutes to 7 minutes, 7 minutes to 8 minutes, 8 minutes to 9 minutes, an 9 minutes to 10 minutes. In embodiments of the disclosure, PLC 120 is configured to switch one or more of the fixed bed reactors from the dehydrogenation mode to a regeneration mode to regenerate the catalyst bed of each of the fixed bed reactors, in response to (a) an absolute value of the mathematical time-derivative of the detected first temperature being less than the first critical value and/or (b) an absolute value of the mathematical time-derivative of the detected second temperature being less than the second critical value. In embodiments of the disclosure, PLC 120 is configured to switch one or more of the fixed bed reactors from the regeneration mode to the dehydrogenation mode, in response to (c) an absolute value of the mathematical time-derivative of the detected first temperature being less than the third critical value and/or (d) an absolute value of the mathematical time-derivative of the detected second temperature being less than the fourth critical value.
Methods of dehydrogenating a hydrocarbon have been discovered. As shown in
According to embodiments of the disclosure, as shown in block 201, method 200 includes providing the programmable logic controller (PLC) 120 to a hydrocarbon dehydrogenation system. According to embodiments of the disclosure, as shown in block 202, method 200 includes initiating a dehydrogenation mode for one or more of the reactors of the dehydrogenation system to dehydrogenate a hydrocarbon and produce a dehydrogenated hydrocarbon. Non-limiting examples of the hydrocarbon can include isobutane, n-butane, propane, ethane, methane, and combinations thereof. In embodiments of the disclosure, initiating at block 202 includes flowing a feed stream comprising the hydrocarbon into the reactor at a reaction temperature, and contacting the hydrocarbon with the catalyst under reaction conditions sufficient to produce a product an effluent stream comprising the dehydrogenated hydrocarbon. In embodiments of the disclosure, the reaction conditions include a reaction temperature of 530 to 690° C. and all ranges and values there between including a reaction temperature of 530 to 540° C., 540 to 550° C., 550 to 560°° C., 560 to 570° C., 570 to 580°° C., 580 to 590° C., 590 to 600° C., 600 to 610° C., 610 to 620°° C., 620 to 630° C., 630 to 640° C., 640 to 650°° C., 650 to 660° C., 660 to 670° C., 670 to 680° C., and 680 to 690° C. The reaction conditions can include a reaction pressure of 0.2 to 1.8 bar and all ranges and values there between including ranges of 0.2 to 0.4 bar, 0.4 to 0.6 bar, 0.6 to 0.8 bar, 0.8 to 1.0 bar, 1.0 to 1.2 bar, 1.2 to 1.4 bar, 1.4 to 1.6 bar, and 1.6 to 1.8 bar. The reaction conditions can further include a weight hourly space velocity of 0.5 to 3.0 hr−1, and all ranges and values there between including ranges of 0.5 to 1.0 hr−1, 1.0 to 1.5 hr−1, 1.5 to 2.0 hr−1, 2.0 to 2.5 hr−1, and 2.5 to 3.0 hr−1. In embodiments of the disclosure, the initiating at block 202 is conducted via PLC 120.
According to embodiments of the disclosure, as shown in block 203, method 200 includes detecting, by the temperature sensors, a first temperature (T1) of a top portion of a catalyst bed for each of the reactors. The detecting at block 203 can be conducted continuously. According to embodiments of the disclosure, as shown in block 204, method 200 includes detecting a second temperature (T2) of a bottom portion of the catalyst bed for each of the reactors. In embodiments of the disclosure, the detecting at block 204 can be conducted continuously. Detecting at blocks 203 and 204 can be conducted simultaneously. As an alternative to being conducted continuously, the detecting at block 203 and/or block 204 can be conducted intermittently with an interval of 1 second to 10 minutes and all ranges and values there between including a ranges of 1 second to 10 seconds, 10 seconds to 20 seconds, 20 seconds to 30 seconds, 30 seconds to 40 seconds, 40 seconds to 50 seconds, 50 seconds to 1 minute, 1 minute, to 2 minute, 2 minutes to 3 minutes, 3 minutes to 4 minutes, 4 minutes to 5 minutes, 5 minutes to 6 minutes, 6 minutes to 7 minutes, 7 minutes to 8 minutes, 8 minutes to 9 minutes, an 9 minutes to 10 minutes.
According to embodiments of the disclosure, as shown in block 205, method 200 includes calculating, by PLC 120, mathematical time-derivatives of the detected first temperature (dT1/dt) and the detected second temperature (dT2/dt) for each of the reactors. In embodiments of the disclosure, calculating at block 205 is conducted continuously. In embodiments of the disclosure, in each cycle of the reactor (i.e., regeneration mode and dehydrogenation mode), the correlation between the first temperature (T1) and time can include two or more linear sections, preferably 6 linear sections. In embodiments of the disclosure, in each cycle of the reactor (i.e., regeneration mode and dehydrogenation mode), the correlation between the second temperature (T2) and time can include two or more linear sections, preferably 4 linear sections.
According to embodiments of the disclosure, as shown in block 206, method 200 includes switching, via PLC 120, one or more of the reactors from the dehydrogenation mode to a regeneration mode to regenerate the catalyst of each of the reactors, in response to (a) an absolute value of the mathematical time-derivative of the detected first temperature being less than a first critical value and/or (b) an absolute value of the mathematical time-derivative of the detected second temperature being less than a second critical value.
According to embodiments of the disclosure, as shown in block 207, method 200 includes switching, via PLC 120, one or more of the fixed bed reactors from the regeneration mode to the dehydrogenation mode, in response to (c) an absolute value of the mathematical time-derivative of the detected first temperature being less than a third critical value and/or (d) an absolute value of the mathematical time-derivative of the detected second temperature being less than a fourth critical value. In embodiments of the disclosure, the first critical value can be in a range of 8 to 14° C./min. The second critical value can be in a range of 5 to 8° C./min. The third critical value can be in a range of 2 to 5° C./min. The fourth critical value can be in a range of 0.1 to 2° C./min.
In embodiments of the disclosure, the first critical value, the second critical value, the third critical value, and the fourth critical value are each obtained from experimentation and/or simulation of the hydrocarbon dehydrogenation process. According to embodiments of the disclosure, the first critical value, the second critical value, the third critical value, and the fourth critical value can vary between Start of Run and End of Run for each reactor. In embodiments of the disclosure, blocks 202-207 are executed via instructions stored in a non-transitory storage medium in PLC 120.
Although embodiments of the present disclosure have been described with reference to blocks of
The systems and processes described herein can also include various equipment that is not shown and is known to one of skill in the art of chemical processing. For example, some controllers, piping, computers, valves, pumps, heaters, thermocouples, pressure indicators, mixers, heat exchangers, and the like may not be shown.
As part of the disclosure of the present disclosure, specific examples are included below. The examples are for illustrative purposes only and are not intended to limit the disclosure. Those of ordinary skill in the art will readily recognize parameters that can be changed or modified to yield essentially the same results.
A temperature profile was plotted for a catalyst bed in a dehydrogenation reactor used for dehydrogenating isobutane during a 24-month run. Temperatures for both the top portion and the bottom portion of the catalyst bed were plotted against time.
The operation conditions are defined as:
Catalyst bed temperature locations are defined as:
Characteristics of these temperature profiles are defined as:
In the graphical representation in
As explained in the previous section, the temperature profiles demonstrate a significant variation in terms of the operational time and catalyst bed location.
The results of the temperature slope (i.e., absolute values for the time derivatives of the temperatures) for the Start of Run (shown in
According to Table 1 and
In the context of the present disclosure, at least the following 15 embodiments are described. Embodiment 1 is a method of dehydrogenating a hydrocarbon. The method includes initiating a dehydrogenation mode for a reactor to dehydrogenate the hydrocarbon. The method further includes detecting a temperature in a catalyst bed of the reactor during the dehydrogenation mode. The method still further includes calculating mathematical time-derivatives of the detected temperature, and switching the reactor from the dehydrogenation mode to a regeneration mode to regenerate the catalyst of the catalyst bed, in response to an absolute value of the mathematical time-derivative of the detected temperature in the catalyst bed being less than a critical value. Embodiment 2 is the method of embodiment 1, wherein the reactor is a fixed bed reactor. Embodiment 3 is the method of any of embodiments 1 and 2, wherein the detecting includes detecting a first temperature of a top portion of a catalyst bed and detecting a second temperature of a bottom portion of the catalyst bed of the reactor during the dehydrogenation mode. Embodiment 4 is the method of any of embodiments 1 to 3, wherein the top portion includes a portion from a top of the catalyst bed to 15% to 22% depth of the catalyst bed, and the bottom portion includes a bottom 10% to 20% depth of the catalyst bed. Embodiment 5 is the method of any of embodiments 1 to 4, wherein the depth of the catalyst bed is about 190 cm, the top portion of the catalyst bed is a region from top of the catalyst bed to 30 cm in the catalyst bed below the top of the catalyst bed, and the bottom portion of the catalyst bed includes a region from 160 cm from top of the catalyst bed to the bottom of the catalyst bed. Embodiment 6 is the method of any of embodiments 1 to 5, wherein the calculating includes calculating mathematical time-derivatives of the detected first temperature and mathematical time-derivatives of the detected second temperature. Embodiment 7 is the method of any of embodiments 1 to 6, wherein the switching includes switching the reactor from the dehydrogenation mode to a regeneration mode to regenerate the catalyst bed, in response to (a) an absolute value of the mathematical time-derivative of the detected first temperature being less than a first critical value and/or (b) an absolute value of the mathematical time-derivative of the detected second temperature being less than a second critical value. Embodiment 8 is the method of any of embodiments 1 to 7, further including switching the reactor from the regeneration mode to the dehydrogenation mode in response to (c) an absolute value of the mathematical time-derivative of the detected first temperature being less than a third critical value and/or (d) an absolute value of the mathematical time-derivative of the detected second temperature being less than a fourth critical value. Embodiment 9 is the method of any of embodiments 1 to 8, wherein each of the initiating, detecting, calculating, and switching steps is conducted continuously. Embodiment 10 is the method of any of embodiments 1 to 9, wherein the hydrocarbon includes isobutane, n-butane, propane, ethane, methane, or combinations thereof.
Embodiment 11 is a method of operating a reaction unit containing one or more fixed bed reactors for dehydrogenating a hydrocarbon. The method includes providing a programmable logic controller (PLC) with: (i) a memory; (ii) a database stored in the memory, the database having a first critical value, a second critical value, a third critical value and a fourth critical value; and (iii) one or more processors communicatively coupled to the memory, the one or more processors configured to switch each of the one or more fixed bed reactors between a dehydrogenation mode and a regeneration mode based on the first critical value, the second critical value, the third critical value, and the fourth critical value. The method further includes initiating, by the PLC, the dehydrogenation mode for one or more of the fixed bed reactors to dehydrogenate the hydrocarbon to produce a dehydrogenated hydrocarbon. The method still further includes continuously detecting a first temperature of a top portion a catalyst bed of each of one or more of the fixed bed reactors. The method additionally includes continuously detecting a second temperature of a bottom portion of the catalyst bed of each of one or more of the fixed bed reactors during the dehydrogenation mode. The method also includes continuously calculating, by the PLC, mathematical time-derivatives of the detected first temperature and the detected second temperature for each of the fixed bed reactors. The method yet further includes switching, via the PLC, one or more of the fixed bed reactors from the dehydrogenation mode to the regeneration mode to regenerate the catalyst bed of each of the fixed bed reactors, in response to (a) an absolute value of the mathematical time-derivative of the detected first temperature being less than the first critical value and/or (b) an absolute value of the mathematical time-derivative of the detected second temperature being less than the second critical value. The method still further includes switching, via the PLC, one or more of the fixed bed reactors from the regeneration mode to the dehydrogenation mode, in response to (c) an absolute value of the mathematical time-derivative of the detected first temperature being less than the third critical value and/or (d) an absolute value of the mathematical time-derivative of the detected second temperature being less than the fourth critical value. Embodiment 12 is the method of embodiment 11, wherein the reaction unit is configured to dehydrogenate isobutane, wherein the reaction unit comprises 3-5 fixed bed reactors in parallel. Embodiment 13 is the method of any of embodiments 11 and 12, wherein the reaction unit is configured to dehydrogenate C3 hydrocarbons, wherein the reaction unit comprises 6-12 fixed bed reactors in parallel. Embodiment 14 is the method of any of embodiments 11 to 13, wherein the PLC is configured to control each of the one or more fixed bed reactors independently. Embodiment 15 is the method of any of embodiments 11 to 14, wherein the catalyst is selected from the group consisting of oxides or carbides of Al, Si, Ti, Zr, Zn, Ce, Sn, Mg, Ca, La, Cr, Cs, Ba, and combinations thereof.
Although embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the above disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
Number | Date | Country | Kind |
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21206125.3 | Nov 2021 | EP | regional |
This application is a National Stage Application under 35 U.S.C. § 371 and claims the benefit of International Application No. PCT/EP2022/080669, filed Nov. 3, 2022, which claims priority to EP 21206125.3, filed Nov. 3, 2021, the contents of both of which are incorporated herein in their respective entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2022/080669 | 11/3/2022 | WO |