Heat storage in chemical reactors

Abstract

A method for producing olefins may include dehydrogenating a first alkane in a first reactor to produce a first effluent including at least one of a first normal olefin or a first diolefin; removing the first effluent from the first reactor; and regenerating the first reactor. The first reactor may include a first dehydrogenation catalyst and a first phase change material.

Description

Technical Field

[0001] The present disclosure relates to the field of heat storage, and in particular to a method for producing olefins and a reactor. Background Art

[0002] Many industrially important catalytic reactions are endothermic and cause a drop in reactor temperature. To counteract this temperature drop, which can negatively affect several reaction parameters, heat needs to be added to the reactor to maintain the reaction.

[0003] One such endothermic process is the dehydrogenation of aliphatic hydrocarbons, which produces olefins used in the production of many petrochemical products. Short-chain saturated hydrocarbons having 2 to 5 carbon atoms per molecule often undergo dehydrogenation to form the corresponding olefins. Olefins can in turn be used for the alkylation of isoparaffins, the etherification of alcohols to prepare motor fuel blending additives, or as monomers for the production of various polymer materials. Olefins can also undergo subsequent dehydrogenation to dienes.

[0004] One particularly useful olefin is propylene, which can be produced by dehydrogenation of propane. Propylene is the world's second largest petrochemical commodity and is used to produce polypropylene, acrylonitrile, acrylic acid, acrolein, propylene oxide and glycols, plasticizer oxo alcohols, cumene, isopropanol and acetone. Growth in propylene production is driven primarily by industrial demand for polypropylene, which is used in everyday products such as packaging materials and outdoor clothing. Other useful olefins include butenes, isobutylene and isopentene, which also have diverse end uses.

[0005] A particularly useful diene is butadiene, which can be produced by dehydrogenation of n-butene. Butadiene is primarily used as a chemical intermediate and as a monomer in the manufacture of polymers such as synthetic rubbers or elastomers including styrene-butadiene rubber (SBR), polybutadiene rubber (PBR), polychloroprene (Neoprene) and nitrile rubber (NR). Another useful diene is isoprene. The main applications of isoprene include use as a monomer in the manufacture of polyisoprene rubber, styrene-isoprene-styrene block copolymers (SIS) and butyl rubber.

[0006] The dehydrogenation of aliphatic hydrocarbons can be carried out by a cyclic, adiabatic process such as Process is underway. Each cycle of the process requires reduction of the catalyst, dehydrogenation of the hydrocarbons, purging and regeneration. The endothermic dehydrogenation reaction reduces the temperature of the catalyst bed, which, combined with coke deposition, reduces its ability to produce the desired product. Typically, the regeneration step provides hot air to the reactor to remove the coke and restore the necessary heat to the catalyst bed. However, this regeneration often fails to heat the reactor evenly and does not fully utilize the catalyst. Summary of the invention

[0007] This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help limit the scope of the claimed subject matter.

[0008] In one aspect, embodiments disclosed herein relate to a method for producing olefins, which may include dehydrogenating a first alkane in a first reactor to produce a first effluent including at least one of a first normal olefin or a first diolefin; removing the first effluent from the first reactor; and regenerating the first reactor. The first reactor may include a first dehydrogenation catalyst and a first phase change material.

[0009] In another aspect, embodiments disclosed herein relate to a reactor including a dehydrogenation catalyst and a phase change material. The phase change material can undergo a phase change at a temperature above 525°C and below 675°C.

[0010] Other aspects and advantages will become apparent from the following description and the appended claims. DETAILED DESCRIPTION

[0011] One or more embodiments disclosed herein generally relate to reactors comprising a phase change material (PCM). The PCM can advantageously provide heat to one or more regions of the reactor, such as to a catalyst. When used in an endothermic process in one or more embodiments, the heat provided by the PCM can offset the temperature drop caused by the endothermic reaction to a certain extent and can prolong the catalytic reaction. Other embodiments disclosed herein relate to methods in which reactions containing PCMs can be used to carry out endothermic reactions.

[0012] By carefully selecting a PCM with an appropriate phase change temperature, practitioners can take advantage of exothermic phase changes to provide heat for reactions. Thus, PCMs can provide a much higher ability to store and release heat when compared to typical components used in reactors. This can be used for a variety of endothermic processes, but is particularly advantageous for reactors that operate dynamically or batchwise, or where a catalyst is used to carry the required heat of reaction. Examples may include cyclic processes with only the catalyst that are run for a relatively short period of time. Examples may include Reactors, reactors for catalytic cracking (such as fluid catalytic cracking, FCC), batch reactors and cyclic catalytic reforming reactors.

[0013] For example, in During the process, the dehydrogenation reactor is periodically shut down due to lack of heat and requires regeneration / reheating. Incorporating the PCM as part of the catalyst bed can allow the reactor to run for a longer period of time before regeneration is required.

[0014] Phase change materials

[0015] The PCM according to embodiments of the present disclosure can be a material that undergoes a phase change under the conditions established in the reactor during a chemical reaction. The PCM is not particularly limited and can be any material that stores thermal energy through latent heat of phase change consistent with the present disclosure. For example, the PCM can undergo any exothermic phase change, such as solid to solid (SS), liquid to solid (freezing), gas to liquid (condensation) or gas to solid (deposition) transition. With the benefit of this disclosure, one of ordinary skill in the art will understand that the nature of the phase change will affect the arrangement and accommodation of the PCM in the reactor. In some embodiments, one or more PCMs can be used in combination.

[0016] In one or more embodiments, PCMs that exhibit a solid-to-solid phase change (SS-PCM) or a liquid-to-solid phase change may be preferred. Such PCMs may not require encapsulation and provide a small volume change when undergoing a phase change. In addition, SS-PCMs limit potential leak formation.

[0017] The PCM according to the present disclosure will generally undergo a phase change at high temperatures and be thermally stable. The PCM can be selected to undergo a phase change at the temperature that the reactor using the PCM will reach. For example, the initial temperature of the reactor can be 690°C, and the phase change temperature of the PCM can be 610°C. As the endothermic reaction proceeds, the reactor and PCM will cool. Once the temperature of the PCM reaches 610°C, a phase change will occur, releasing heat and maintaining the chemical reaction.

[0018] In one or more embodiments, the PCM can have a phase transition temperature ranging from about 300°C to about 700°C. For example, the PCM can have a phase transition temperature ranging from a lower limit of any one of 300, 350, 400, 450, 500, 550, or 600°C to an upper limit of any one of 400, 450, 500, 550, 600, 650, or 700°C, wherein any lower limit can be used in combination with any upper limit. In some embodiments, wherein the PCM is used In the process, the PCM may specifically have a phase transition temperature in the range of from about 550° C. to about 650° C. For example, the PCM may have a phase transition temperature in the range of from a lower limit of any one of 550, 570, 590, 600, 610, 620, or 630° C. to an upper limit of any one of 570, 590, 600, 610, 620, 630, or 650° C., wherein any lower limit may be used in combination with any upper limit.

[0019] The PCM in a particular embodiment may be selected to be catalytically inert to one or more, but preferably all, of the feedstocks, products, and any intermediates produced for a particular process. Use of a PCM that is catalytically inert under reactor conditions may advantageously limit the production of by-products and may improve the selectivity and / or efficiency of the process. The PCM may be produced by any method known in the art.

[0020] The PCM in one or more embodiments may include one or more metal salts and / or metal alloys. PCMs according to the present disclosure may include NaNO3, CaCl2 / NaCl, Al, Si / Al, BaCl2, or Zn. In a particular embodiment, the PCM may include a mixture of 35.9 mol% BaCl2 and 64.1 mol% CaCl2, providing a melting point of about 608°C. One of ordinary skill will appreciate that the composition of a PCM may affect its latent heat of phase change (i.e., its ability to store heat) as well as its phase change temperature (i.e., its suitability for use in a given process).

[0021] The PCM in one or more embodiments can be enclosed, which can advantageously inhibit corrosion. The enclosure of one or more embodiments can be one or more tubes, pipes or other small containers. The choice of material for enclosing the PCM depends on the conditions to which the PCM will be exposed. The enclosure in one or more embodiments can be made of alumina ceramics (such as those of Fukahori et al., Applied Energy, 170, 2016, pages 324 to 328) or various metals (such as those of Jacob et al., Renewable and Sustainable Energy Reviews, 48, 2015, pages 79 to 87).

[0022] In some embodiments, the PCM may be encapsulated. In certain embodiments, the PCM may consist of small encapsulated particles (such as in US2017 / 0283258 and US2015 / 0190796).

[0023] Reactor with PCM

[0024] The reactor in one or more embodiments of the present disclosure may include one or more catalysts and one or more PCMs. One of ordinary skill in the art will appreciate that the choice of catalyst is highly dependent on the reaction to be performed and is not particularly limited. As described above, the choice of PCM depends primarily on the process conditions (i.e., temperature, pressure) of the reaction and the catalytic inertness of the PCM.

[0025] The catalyst in one or more embodiments is not particularly limited. In some embodiments, it can be any dehydrogenation catalyst known in the art for realizing the catalytic dehydrogenation of hydrocarbons to produce olefins. In one or more embodiments, the catalyst can be a dehydrogenation catalyst active for converting propane into propylene. In some embodiments, the catalyst can include a 4 to 6 group metal oxide. In one or more embodiments, the catalyst can include a catalytically active material dispersed on a carrier. Such a carrier can be selected to increase the surface area of ​​the active material, and such a carrier can be any carrier known in the art. In a specific embodiment, the carrier can be one or more of aluminum oxide, silicon dioxide, etc.

[0026] The reactor of one or more embodiments may further include an inert material. The choice of inert material depends on the process at hand. For example, for a dehydrogenation reaction, such as In the process, the inert material can be selected to provide a high heat capacity to limit the temperature change of the catalyst bed during the endothermic dehydrogenation reaction. In some embodiments, the inert material can be a high density alumina. The inert material in some embodiments can be mixed with the catalyst in the catalyst bed. The physical form of the inert material is not particularly limited, but can be in a generally granular or pelletized form. In the dehydrogenation process, the relative volumes of the inert material and the catalyst can depend on many factors, including the type of hydrocarbon feed used.

[0027] The reactor in one or more embodiments can be a fixed bed reactor or a fluidized bed reactor. It will be understood by a person of ordinary skill that the type of reactor used depends on the needs of the specific reaction to be performed. For example, The process typically utilizes a fixed bed reactor. The type of reactor used may affect the physical properties required of the PCM. For example, a fluidized bed reactor in one or more embodiments may use a packaged PCM that has a sufficiently small particle size and sufficient strength to pass through the fluidized bed. Such an embodiment may allow for a reduced catalyst / feed ratio.

[0028] The reactor in one or more embodiments can be prepared by physically combining a catalyst, a PCM, and an optional inert material. A desired amount of catalyst can be combined with a predetermined amount of PCM and an inert material. One of ordinary skill in the art will appreciate that the relative amounts of these components depend on the intended use of the reactor.

[0029] In one or more embodiments, the reactor of the present disclosure can include, relative to the total weight of the reactor charge, an amount of PCM in a range from a lower limit of any one of 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 wt % to an upper limit of any one of 3.0, 5.0, 7.0, 9.0, and 15.0 wt %, wherein any lower limit can be used in combination with any mathematically compatible upper limit. In one or more embodiments, the reactor of the present disclosure can include, relative to the total volume of the reactor charge, an amount of PCM in a range from a lower limit of any one of 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 vol % to an upper limit of any one of 3.0, 5.0, 7.0, 9.0, and 15.0 vol %, wherein any lower limit can be used in combination with any mathematically compatible upper limit.

[0030] In one or more embodiments, the reactor of the present disclosure can include, relative to the total weight of the dehydrogenation catalyst, an amount of PCM in a range from a lower limit of any one of 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 wt % to an upper limit of any one of 15.0, 20.0, 25.0, 30.0, and 35.0 wt %, wherein any lower limit can be used in combination with any mathematically compatible upper limit. In one or more embodiments, the reactor of the present disclosure can include, relative to the total volume of the dehydrogenation catalyst, an amount of PCM in a range from a lower limit of any one of 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 vol % to an upper limit of any one of 15.0, 20.0, 25.0, 30.0, and 35.0 vol %, wherein any lower limit can be used in combination with any mathematically compatible upper limit.

[0031] The reactor of one or more embodiments may place the PCM in a specific position relative to the catalyst to provide a desired heat transfer rate. In some embodiments, the PCM may be incorporated into the reactor by storing it inside a sealed cylindrical tube. In a reactor, these cylindrical tubes are spaced apart in a grid pattern to evenly distribute heat. Catalysts can be loaded around the cylinders to fill the space.

[0032] The reactor in one or more embodiments may further include a heat generating material (HGM). The HGM may be catalytically inert under process conditions, but may generate heat after being reduced and / or oxidized. Such HGM may be any suitable material known in the art, for example, may be selected from copper, chromium, molybdenum, vanadium, cerium, yttrium, scandium, tungsten, manganese, iron, cobalt, nickel, silver, bismuth and combinations thereof. In one or more embodiments, the reactor may include an amount of HGM in the range of a lower limit of 1.0, 3.0, 5.0, 7.0 or 9.0 wt % to an upper limit of 7.0, 9.0, 11.0, 13.0, 15.0 or 20.0 wt %, wherein any upper limit may be used with any mathematically compatible lower limit.

[0033] method

[0034] The method in one or more embodiments of the present disclosure may involve any endothermic catalytic reaction and may include the use of any of the above-described catalyst beds that may be suitable. In certain embodiments, the method may be a cyclic process.

[0035] In some embodiments, the use of PCMs can increase the duration of a production cycle in a reactor where most of the heat of reaction is supplied by cooling the catalyst. Storing more energy in the catalyst bed in the form of latent heat of the PCM can allow longer duration production cycles and reduced regeneration cycles. In embodiments of the process where reactors dynamically alternate between dehydrogenation and regeneration cycles, the use of PCMs can reduce capital costs by reducing the regeneration time per reactor, meaning that fewer reactors are required to provide a given production capacity.

[0036] One or more embodiments The process may include the use of one or more reactors containing PCM. Although the number of reactors containing PCM is not particularly limited, in certain embodiments, the process may include the use of two reactors, four reactors, eight reactors, or ten reactors. The process can be a continuous process where multiple reactors containing PCM are operated in a cyclic manner with a controlled dehydrogenation and reheating / regeneration sequence.

[0037] In one or more embodiments During the dehydrogenation cycle of the process, over time, as dehydrogenation proceeds, the catalyst bed temperature is gradually reduced by absorbing heat from the catalyst bed through endothermic reactions. This temperature reduction, combined with coke deposited on the catalyst, reduces its ability to produce the desired product. However, when the phase transition temperature of the PCM is reached, the PCM can undergo an exothermic transition and provide heat to the catalyst bed, which is similar to conventional Compared to the conventional process, the duration of the reaction cycle is increased. However, in order to remove the coke and restore the necessary heat to the catalyst bed, the catalyst needs to be periodically reheated with hot air.

[0038] In one or more embodiments, the use of PCM can result in an increased duration of the dehydrogenation cycle relative to the regeneration cycle. In some embodiments, the duration of the dehydrogenation cycle can be 1.1 times or more, 1.2 times or more, 1.3 times or more, 1.4 times or more, or 1.5 times or more the duration of the regeneration cycle.

[0039] Thus, the process in one or more embodiments may include one or more dehydrogenation reaction zones, each zone comprising two or more reactors operated in parallel, wherein one reactor may produce olefins and / or diolefins while another reactor is purged and the catalyst is regenerated and reheated to the desired reactor temperature before being brought back online to produce olefins and / or diolefins.

[0040] The dehydrogenation process according to the embodiments of the present invention may include a fixed bed reactor operated at low pressure and elevated temperature. Conditions may be selected to optimize the complex relationship between conversion, selectivity, and energy consumption. The temperature and pressure may be from 400 to 750° C. and from 0.01 to 1 kg / cm 2 In a particular embodiment, they may be from 575 to 650°C and from 0.1 to 0.5 kg / cm 2 within the absolute pressure range.

[0041] The method in one or more embodiments can include the dehydrogenation of one or more hydrocarbons. In some embodiments, one or more of the hydrocarbons can be selected from C2-C5 aliphatic hydrocarbons. In a specific embodiment, one or more of the hydrocarbons can be selected from propane, normal butane and isobutane. For example, in the reaction section, when passing through a catalyst bed containing PCM, propane is converted into propylene, isobutane is converted into isobutylene, and / or normal butane can be converted into normal butene and butadiene. If the processing of propane and butane is carried out simultaneously, a separate dedicated C3 dehydrogenation reactor is used for the conversion of propane to propylene, and a separate dedicated C4 dehydrogenation reactor is used for the conversion of butane to butenes and / or isobutane to isobutylene. Reactor conditions (catalyst, catalyst loading, space velocity, hydrocarbon feed temperature, air / hydrocarbon ratio, air temperature, etc.) can be optimized for the process to be carried out in the reactor.

[0042] In one or more embodiments, the side reactions occurring simultaneously with the main reaction result in the formation of some light hydrocarbon gases and heavy hydrocarbons, as well as the deposition of coke on the catalyst. When propane is dehydrogenated in a dedicated reaction zone, the overall selectivity of propane to propylene is higher, when isobutane is dehydrogenated in a dedicated reaction zone, the overall selectivity of isobutane to isobutylene is higher, and when n-butane / n-butene is dehydrogenated in a dedicated reaction zone, the overall selectivity of n-butane to n-butene / butadiene is higher than the selectivity that can be achieved when propane, isobutane, and n-butane are combined in the same reaction zone. In some embodiments, the overall selectivity of propane to propylene can be greater than 88 mole%, the overall selectivity of isobutane to isobutylene can be greater than 90 mole%, and the overall selectivity of n-butane to n-butene / butadiene can be greater than 60 mole%.

[0043] As described above, the method herein may include cyclic operation. A system according to an embodiment of the present invention may include a control system configured to: operate a reactor in each reaction zone in a dehydrogenation cycle; operate a reactor in a regeneration cycle; and operate a reactor in a purge or evacuation / reduction cycle. The control system may be further configured to sequentially operate two or more valves arranged in a parallel flow arrangement, for providing air, steam and inert gas from a common regeneration system to the reactor in the reheating / regeneration cycle and the reactor in the purge / evacuation / reduction cycle as required, and for providing propane, normal butane and isobutane to the reactor in the dehydrogenation cycle as required. In other words, the control system may be configured to operate the reactor in the dehydrogenation cycle in a staggered cycle so that the purge cycle, regeneration cycle or evacuation / reduction cycle of the reactor do not overlap. The cycle timing meter sequences the actuation of the hydraulically operated valve to control the operation. The system may be appropriately interlocked to sequentially ensure the safe operation of the valve and prevent the mixing of air and hydrocarbon gas.

[0044] After the dehydrogenation reaction cycle, while the reactor system is still under vacuum, the reactor can be thoroughly purged with steam, thereby stripping residual hydrocarbons from the catalyst and reactor to a recovery system. Reheating of the catalyst can be carried out at a pressure slightly above atmospheric pressure. The reheat air is usually supplied by a gas turbine or air compressor and heated to the required temperature in a direct-fired duct burner before passing through the reactor. In addition to burning the coke off the catalyst, the reheat air is also used to restore the temperature profile of the bed to its initial start-up conditions and catalyst activity. The reheated air leaving the reactor can be used to generate steam in a waste heat boiler.

[0045] When the reheating of the reactor is complete, the reactor is re-evacuated before the next start-up dehydrogenation cycle. Before the introduction of the hydrocarbon feed, a hydrogen-rich tail gas can be introduced into the reactor for a short time to remove absorbed oxygen from the catalyst bed. This reduction step reduces feed losses due to combustion and restores the catalytic metals (such as chromium) on the catalyst to their active state. The reheated air stream leaving the reactor flows to a waste heat boiler, which can be used to generate and superheat high-pressure steam.

[0046] The embodiments herein can be used for the production of any relative amounts of propylene, isobutylene, and butadiene, and in any capacity combination. The methods herein can be used to produce: propylene and isobutylene, propylene and butadiene; isobutylene and normal-butadiene; propylene, isobutylene, and butadiene; and combinations of any product ratios. In the case of producing butadiene, normal-butene can be extracted as a by-product. The equipment can be designed for "once-thru" operation. In various embodiments, isobutane and normal-butane can be processed together in the same dedicated dehydrogenation reactor; alternatively, isobutane and propane can be processed together in the same dedicated dehydrogenation reactor.

[0047] In one or more embodiments, any number of dehydrogenation reactors can be used according to product capacity. LTRU and distillation train devices (train) can be customized according to product structure and capacity. During each cycle, the reactor conditions of each dehydrogenation reactor can be different. Air flow and temperature can be changed during the reheating / regeneration step of each dehydrogenation reactor to maintain the thermal balance of the entire reactor. The distillation train device can include a deethanizer, a depropanizer and / or a C3 splitter for propylene production. The distillation train device can also include a pre-fractionator for butadiene separation. A C2 splitter can be added to reclaim a high-purity ethylene product.

[0048] Example

[0049] The following examples are illustrative only and should not be construed as limiting the scope of the present disclosure.

[0050] The following process conditions were simulated for three examples:

[0051] Hydrocarbon cycle:

[0052] Hydrocarbon feed temperature = 578.8°C / 851.9K

[0053] Hydrocarbon WHSV = 0.483h -1

[0054] Pressure = 42 kPa (assumed constant in the reactor)

[0055] Steam purge:

[0056] This simulation ignores

[0057] Air regeneration cycle:

[0058] Air inlet temperature = 908.5K

[0059] Air WHSV = 3 1 / h

[0060] reduction:

[0061] Reducing gas inlet temperature = 783.9K

[0062] Reducing gas WHSV = 0.3 1 / h

[0063] The reducing gas was set to 60% by volume of hydrogen

[0064] Table 1: Simulation results

[0065]

[0066] The above examples show that the use of PCM allows the reactor to run longer in the dehydrogenation cycle. This can ultimately lead to higher catalyst utilization and fewer reactors having to be constructed, which means lower capital costs to build a Catofin unit.

[0067] Although the foregoing description has been described herein with reference to particular devices, materials, and embodiments, it is not intended to be limited to the details disclosed herein; rather, it extends to all functionally equivalent structures, methods, and uses, such as are within the scope of the appended claims. In the claims, means-plus-function clauses are intended to cover structures described herein as performing the described function, and include not only structural equivalents, but also equivalent structures. Thus, while a nail and a screw may not be structural equivalents because a nail employs a cylindrical surface to secure wooden parts together, while a screw employs a helical surface, a nail and a screw may be equivalent structures in the context of fastening wooden parts. Applicant expressly disclaims any limitation of any claim herein under 35 U.S.C. §112(f), except where a claim expressly uses the word "means to" and limitations associated with the function.

Claims

1. A method for producing olefins, the method comprising: dehydrogenating a first alkane in a first reactor to produce a first effluent comprising at least one of a first normal olefin or a first diolefin; removing the first effluent from the first reactor; and regenerating the first reactor, wherein the first reactor comprises a fixed bed reactor, the fixed bed reactor comprising a first dehydrogenation catalyst, the first dehydrogenation catalyst being disposed about a sealed cylindrical tube containing a first phase change material, wherein the sealed cylindrical tubes are spaced apart within the fixed bed reactor of the first reactor, and the sealed cylindrical tubes are arranged in a grid pattern within the fixed bed reactor; and The dehydrogenation of the first alkane causes the temperature of the first phase change material to decrease, so that the first phase change material undergoes a phase change.

2. The method of claim 1, wherein the phase change of the first phase change material provides thermal energy to the first dehydrogenation catalyst sufficient to maintain dehydrogenation of the first alkane.

3. The process according to claim 1 or 2, wherein the dehydrogenation of the first alkane is performed for at least 1.2 times the duration of the regeneration of the first reactor.

4. The method according to claim 1 or 2, wherein the first reactor comprises the first phase change material in an amount of 5 to 30 wt% relative to the total weight of the dehydrogenation catalyst.

5. The method according to claim 1 or 2, wherein the first reactor contains the first phase change material in an amount of 5 to 30 volume % relative to the total volume of the dehydrogenation catalyst.

6. The method according to claim 1 or 2, wherein the first phase change material undergoes a phase change at a temperature of 600°C or higher and 620°C or lower.

7. The method according to claim 1 or 2, wherein the first alkane is one of the group consisting of propane, n-butane and isobutane.

8. The method of claim 1 or 2, wherein the first phase change material comprises barium chloride and calcium chloride.

9. The method according to claim 1 or 2, further comprising: dehydrogenating the second alkane in a second reactor to produce a second effluent comprising at least one of a second normal olefin or a second diolefin, removing the second effluent from the second reactor; and regenerating the second reactor, wherein the second reactor comprises a fixed bed reactor, the fixed bed reactor containing a second dehydrogenation catalyst, the second dehydrogenation catalyst being disposed around a sealed cylindrical tube containing a second phase change material, wherein the sealed cylindrical tubes are spaced apart within the fixed bed reactor of the second reactor, and the sealed cylindrical tubes are arranged in a grid pattern within the fixed bed reactor, and wherein the second dehydrogenation catalyst fills spaces between the sealed cylindrical tubes, wherein the second alkane is different from the first alkane; and The dehydrogenation of the second alkane causes the temperature of the second phase change material to decrease, so that the second phase change material undergoes a phase change.

10. The method of claim 9, wherein a phase change temperature of the second phase change material is different from a phase change temperature of the first phase change material.

11. A reactor comprising: A fixed bed reactor, the fixed bed reactor comprising: Dehydrogenation catalysts; and A phase change material, wherein the phase change material undergoes a phase change at a temperature above 525°C and below 675°C; wherein the dehydrogenation catalyst is disposed around a sealed cylindrical tube containing the phase change material, wherein the sealed cylindrical tubes are spaced apart within a fixed bed reactor of the reactor, and the sealed cylindrical tubes are arranged in a grid pattern within the fixed bed reactor, and wherein the dehydrogenation catalyst fills the spaces between the sealed cylindrical tubes.

12. The reactor according to claim 11, wherein the reactor comprises the phase change material in an amount of 5 to 30 wt% relative to the total weight of the dehydrogenation catalyst.

13. The reactor according to claim 11 or 12, wherein the reactor comprises the phase change material in an amount of 5 to 30% by volume relative to the total volume of the dehydrogenation catalyst.

14. The reactor according to claim 11 or 12, wherein the phase change material undergoes a phase change at a temperature above 550°C and below 650°C.

15. The reactor of claim 14, wherein the phase change material undergoes a phase change at a temperature above 600°C and below 620°C.

16. The reactor of claim 11 or 12, wherein the phase change material comprises barium chloride and calcium chloride.

17. The reactor of claim 16, wherein the phase change material consists of barium chloride and calcium chloride.

18. The reactor of claim 11 or 12, wherein the phase change material is encapsulated.

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