Dehydrogenation reaction self-heating device and self-heating method based on hydrogen permeation membrane reactor

Abstract

The invention provides a dehydrogenation reaction self-heating device based on a hydrogen permeation membrane reactor and a self-heating method, and belongs to the field of dehydrogenation, the dehydrogenation reaction self-heating device comprises a reactor main body, the reactor main body comprises a reaction shell and a hydrogen permeation assembly arranged in the reaction shell, and the interior of the reaction shell is divided into a dehydrogenation reaction cavity and a permeation cavity through the hydrogen permeation assembly; the reaction shell is provided with a dehydrogenation raw material inlet, a dehydrogenation product outlet, an oxygen-containing gas inlet and a permeation cavity tail gas outlet, the hydrogen permeation assembly comprises a reaction layer and a hydrogen permeation layer, the reaction layer is filled with a dehydrogenation catalyst bed layer, and along with dehydrogenation reaction, oxygen in a permeation cavity and separated hydrogen are subjected to oxidation-reduction reaction to release heat on the basis of a porous nickel layer; and heat is provided for the dehydrogenation reaction cavity. Compared with the prior art, the hydrogen permeation assembly with the single conduction function is arranged, and the technical problems that in the existing oxygen oxidation heat supply process, the gas phase reaction rate is low, unsaturated products can be generated, and the reaction between introduced oxygen and raw materials with complex components is uncontrollable are solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of compound dehydrogenation, more specifically, it relates to a self-heating device for dehydrogenation reaction based on a hydrogen-permeable membrane reactor, and a self-heating method for dehydrogenation reaction. BACKGROUND

[0002] The dehydrogenation reaction of alkane and aromatic hydrocarbon derivatives is the core process for the industrial production of high-value-added olefins and aromatic hydrocarbons. The products are key polymerization raw materials for the synthesis of plastics, rubbers, resins and other high molecular materials, and play an indispensable role in the petrochemical and polymer material industries. Such dehydrogenation reactions are all strong endothermic reactions, and the reaction process needs to maintain a high temperature environment of 500-800℃, so stable and efficient heating of the reactor is crucial to the reaction efficiency, product selectivity and process economy.

[0003] Currently, the common heating methods for industrial dehydrogenation reactors have many limitations: the energy consumption and equipment maintenance cost of electric heating method are high, and local overheating phenomenon is easy to occur due to uneven contact heat transfer, among which the inductive heating method is also limited by the material of the reactor, and has narrow applicability; in the heat medium heating, when using heat conducting oil as the heat medium, there is a safety hazard of easy oxidation and coking at high temperature, which also reduces the heat transfer efficiency, while using steam as the heat medium is restricted by the pressure condition, and the condensed water produced by steam condensation is easy to cause equipment corrosion, resulting in energy waste; the temperature uniformity of open flame heating method is poor, and the temperature control precision is low, which not only affects the reaction stability, but also brings environmental problems and fire safety risks caused by fuel combustion.

[0004] To solve the problem of heating for dehydrogenation reaction, the industry has tried to use self-heating reforming technology, which is based on the principle of introducing oxygen to cause partial oxidation exothermic reaction with fuel. This technology has the characteristics of rapid heat release and rapid response, and can adapt to production fluctuations by adjusting the oxygen feed, and can realize internal utilization of reaction heat to improve energy efficiency, but it has defects that are difficult to overcome in actual application: on the one hand, the introduction of oxygen will cause the oxidation side reaction of unsaturated products such as olefins and styrene generated by dehydrogenation reaction, greatly reducing the selectivity of target products; on the other hand, the hydrogen and olefins generated by dehydrogenation reaction are both flammable gases, which are easy to form an explosive atmosphere when mixed with the permeated oxygen, with high safety risk. In addition, the oxidation exothermic process is easy to cause local high temperature or temperature fluctuation, which aggravates the side reactions such as cracking, isomerization and catalyst coking of raw materials and products, and the generated water vapor and CO, etc. will destroy the structure of dehydrogenation catalyst or cause the deactivation of active components, and additional separation process is needed to handle the by-products, increasing the separation cost and energy consumption. The above problems make the self-heating reforming technology fundamentally contradictory to the oxygen-free and precise temperature control environment required by the dehydrogenation reaction, limiting its practical application value. SUMMARY

[0005] The present application aims to provide a dehydrogenation reaction self-heating device based on a hydrogen-permeable membrane reactor to solve the technical problems of low gas phase reaction rate and uncontrollable reaction between introduced oxygen and complex raw materials in the existing oxygen oxidation heating process.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is to provide a dehydrogenation reaction self-heating device based on a hydrogen-permeable membrane reactor, comprising: A reactor main body comprising a reaction shell and a hydrogen-permeable assembly arranged in the reaction shell, the inside of the reaction shell is divided into a dehydrogenation reaction cavity and a permeation cavity which are physically isolated from each other by the hydrogen-permeable assembly; The reaction shell is provided with a dehydrogenation raw material inlet, a dehydrogenation product outlet, an oxygen-containing gas inlet and a permeation cavity tail gas outlet, the dehydrogenation raw material inlet and the dehydrogenation product outlet communicate with the dehydrogenation reaction cavity, and the oxygen-containing gas inlet and the permeation cavity tail gas outlet communicate with the permeation cavity; The hydrogen-permeable assembly comprises a reaction layer and a hydrogen-permeable layer arranged in sequence along the dehydrogenation path, the reaction layer is filled with a dehydrogenation catalyst bed layer, and the hydrogen-permeable layer is a membrane structure with a porous metal layer. With the progress of dehydrogenation reaction, oxygen is oxidized to nickel oxide on the porous nickel layer, hydrogen permeating through the hydrogen-permeable layer reacts with nickel oxide, and hydrogen and oxygen undergo a solid-phase oxidation-reduction reaction based on porous nickel to provide the heat required for the dehydrogenation reaction cavity.

[0007] In a feasible implementation, the hydrogen-permeable layer further comprises a palladium alloy membrane, a palladium-yttrium alloy membrane, a palladium-silver alloy membrane, a porous Composite ceramic membrane and iron-based alloy hollow fiber membrane or SAPO-34 molecular sieve membrane.

[0008] In a feasible implementation, the dehydrogenation reaction self-heating device based on a hydrogen-permeable membrane reactor further comprises a temperature control system, the temperature control system comprising: A temperature sensor is arranged in the dehydrogenation reaction cavity and the permeation cavity; A flow regulating valve connected to the oxygen-containing gas inlet; A controller in communication with the temperature sensor and the flow regulating valve to adjust the feed flow of oxygen-containing gas in real time according to the dehydrogenation reaction cavity temperature to control the heat release rate of the hydrogen-oxygen reduction reaction.

[0009] In a feasible implementation, the dehydrogenation reactor based on the hydrogen permeation membrane further comprises an auxiliary heating system, which is an electric heating wire embedded in the reactor wall, an electromagnetic induction coil wound on the outside of the reactor, or a start-up burner in communication with the outside of the reactor, for providing supplemental heat when the device is started, the load fluctuates, or the hydrogen permeation membrane side is insufficiently heated.

[0010] In a feasible implementation, the dehydrogenation catalyst in the dehydrogenation cavity is one of a supported Pt-Sn catalyst, a catalyst or a catalyst system; and the permeation cavity is filled with a hydrogen oxidation catalyst, which is a supported platinum or palladium catalyst.

[0011] Compared with the prior art, in the specific implementation of the dehydrogenation reactor based on the hydrogen permeation membrane, the reaction shell and the hydrogen permeation assembly are arranged on the reactor body, the hydrogen permeation assembly can separate the reaction shell into a physically isolated dehydrogenation cavity and a permeation cavity, the dehydrogenation cavity is connected to the dehydrogenation raw material inlet and the dehydrogenation product outlet, the permeation cavity is connected to the oxygen-containing gas inlet and the permeation cavity tail gas outlet, and the hydrogen permeation assembly is sequentially arranged along the dehydrogenation path by the reaction layer and the hydrogen permeation layer. The reaction layer is filled with a dehydrogenation catalyst bed to promote the dehydrogenation reaction, the hydrogen permeation layer is made of a material with high selectivity to hydrogen to allow selective permeation of hydrogen, and the hydrogen generated by the dehydrogenation reaction permeates into the permeation cavity under the driving force of the partial pressure difference. In the above process, oxygen is oxidized to form nickel oxide with the nickel metal layer, and hydrogen and nickel oxide undergo an oxidation-reduction reaction to release heat, which is transferred back to the dehydrogenation cavity through the hydrogen permeation assembly to provide heat energy for the continuous endothermic dehydrogenation reaction, achieving the technical effect of self-heating. Further, it can solve the technical problems of high energy consumption and low efficiency caused by the need for external heat source in traditional dehydrogenation reactions.

[0012] The oxygen reacts with hydrogen on the permeation side to produce water, which can reduce the pressure of hydrogen on the permeation side and increase the pressure difference between the reaction side and the permeation side, facilitating the smooth progress of the entire dehydrogenation reaction, and solving the problems of uncontrollable exothermic reaction of oxygen with dehydrogenation raw materials and easy oxidation of unsaturated products such as olefins and styrene on the reaction side. In addition, it can also solve the technical problems of local high temperature or temperature fluctuation caused by the oxidation exothermic process, which aggravates the cracking, isomerization and catalyst coking of raw materials and products, and the generated water vapor also damages the structure of the dehydrogenation catalyst or causes the deactivation of the active components, and the additional separation process is required to handle CO, and other by-products, increasing the separation cost and energy consumption.

[0013] In addition, the temperature sensor arranged can monitor the reaction temperature in real time, and the controller can adjust the flow regulating valve to control the flow of the oxygen-containing gas according to the temperature data feedback, so as to accurately regulate the heat release rate of the permeation cavity, realize the stable control of the dehydrogenation reaction cavity temperature, and achieve the technical effects of maintaining the reaction in the optimal temperature range and avoiding the temperature fluctuation to cause the reaction efficiency to decrease or the catalyst to be deactivated, thereby favorably solving the technical problems that the dehydrogenation reaction is sensitive to the temperature and the traditional control mode is difficult to adjust the heat supply in real time.

[0014] As for the auxiliary heating system in the present application, the electric heating wire embedded in the reactor wall, the electromagnetic induction coil wound outside the reactor or the start-up burner in communication with the outside of the reactor can be used to start up the entire self-heating device to supplement heat when the hydrogen permeation membrane fails to supply heat, so that the reactor can quickly reach the reaction temperature and the stable operation of the reactor can be maintained.

[0015] Another object of the present application is to provide a dehydrogenation reaction self-heating method, which adopts the dehydrogenation reaction self-heating device based on the hydrogen permeation membrane reactor as described above and comprises the following steps. S1, preheating the reactor as a whole to above the dehydrogenation reaction starting temperature; S2, introducing an alkane or aromatic hydrocarbon derivative raw material into the dehydrogenation reaction cavity to generate a mixture containing olefin or aromatic hydrocarbon products and hydrogen under the action of a dehydrogenation catalyst; S3, the hydrogen generated in the dehydrogenation reaction cavity selectively permeates into the permeation cavity under the driving force of the partial pressure difference; S4, introducing an oxygen-containing gas into the permeation cavity, and performing an oxidation-reduction reaction between hydrogen and oxygen based on the porous nickel layer to release heat, and the hydrogen permeation assembly and the reactor wall transfer heat to the dehydrogenation reaction cavity to provide heat energy for the continuous dehydrogenation endothermic reaction; S5, collecting the product mixture rich in olefins or aromatic hydrocarbons from the dehydrogenation product outlet of the dehydrogenation reaction cavity; and discharging the tail gas mainly containing water vapor from the tail gas outlet of the permeation cavity.

[0016] In a feasible implementation manner, the step S4 further comprises the following steps: S401, monitoring the dehydrogenation reaction cavity temperature in real time, and accurately controlling the heat release rate of the hydrogen-oxygen reduction reaction by adjusting the flow of the oxygen-containing gas, so that the operating temperature of the dehydrogenation reaction cavity is stably maintained at 500-650 DEG C.

[0017] In a feasible implementation manner, the hydrogen partial pressure difference between the two sides of the hydrogen permeation assembly is maintained at 0.1-0.5 MPa, so as to ensure that the hydrogen has an economically feasible permeation rate.

[0018] In one possible implementation, the oxygen-containing gas is air, oxygen-enriched air or pure oxygen; the molar ratio of the amount of oxygen introduced into the permeation cavity to the amount of hydrogen permeated is between 0.5 and 1.2 to ensure sufficient combustion of hydrogen and avoid potential oxidative damage to the membrane material. The molar ratio of the amount of oxygen introduced into the permeation cavity to the amount of hydrogen permeated is between 0.5 and 1.2 to ensure sufficient combustion of hydrogen and avoid potential oxidative damage to the membrane material.

[0019] In one possible implementation, the dehydrogenation reaction self-heating method is applicable to any one of ethylbenzene dehydrogenation to styrene, propane dehydrogenation to propylene, and isobutane dehydrogenation to isobutene.

[0020] Compared with the prior art, the dehydrogenation reaction self-heating method described above preheats the entire reactor to above the dehydrogenation reaction starting temperature, introduces an alkane or arene derivative raw material into the dehydrogenation reaction cavity to perform a dehydrogenation reaction, hydrogen selectively permeates through the hydrogen permeation membrane into the permeation cavity under the driving force of the partial pressure difference, and an oxidative exothermic reaction occurs with the introduced oxygen-containing gas, heat is transferred back to the dehydrogenation reaction cavity, and the dehydrogenation reaction self-heating cycle and the pressure reduction process on the hydrogen permeation side are realized in combination with the separation effect of the hydrogen permeation membrane and the exothermic characteristics of the oxidation-reduction reaction, without the need for an external heat source, thereby reducing energy consumption and simplifying the operation. In addition, in the specific implementation process, the oxidation-reduction reaction between oxygen and hydrogen is based on nickel metal, and the product is water, which can reduce the pressure of hydrogen on the permeation side, facilitate the smooth progress of the entire dehydrogenation reaction, and solve the problems of uncontrollable exothermic reaction between oxygen and dehydrogenation raw materials and easy occurrence of oxidation side reactions of unsaturated products such as olefins and styrene caused by the presence of oxygen on the reaction side. In addition, it can also solve the technical problems of local high temperature or temperature fluctuation easily caused by the oxidative exothermic process, which aggravates the side reactions of cracking, isomerization and catalyst coking of raw materials and products, and the generated water vapor also damages the structure of the dehydrogenation catalyst or causes the deactivation of the active components. At the same time, additional separation processes are required to handle by-products such as CO, and other by-products, which increases the separation cost and energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort. In the drawings: Fig. 1 A front view of the dehydrogenation reaction self-heating device based on the hydrogen permeation membrane reactor provided by the present application; Fig. 2 A step diagram of the dehydrogenation reaction self-heating method of the present application.

[0022] In the drawings: ​1、reactor main body; 11, reaction shell; 110, dehydrogenation reaction cavity; 111, permeation cavity; 12, hydrogen permeation assembly; 121, reaction layer; 122, hydrogen permeation layer. DETAILED DESCRIPTION

[0023] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0024] In the description of the present application, it should be noted that if the terms indicating the orientation or position relationship such as "upper", "lower", "inner", "back" and the like appear, they are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0025] In addition, in the description of the present application, unless otherwise explicitly limited, the terms "mounting", "connecting", "connection", "connector" should be understood broadly. For example, the connection can be a fixed connection, or a detachable connection, or an integral connection; can be a mechanical connection, or an electrical connection; can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood in conjunction with the specific circumstances.

[0026] In order to make the technical problems to be solved by the present application, the technical solutions and the beneficial effects more clear, the present application will be further described in detail below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0027] Please refer to Figs. 1-2The self-heat supply device for dehydrogenation reaction based on the hydrogen permeation membrane reactor comprises a reactor main body 1, and specifically, the reactor main body 1 comprises a reaction shell 11 and a hydrogen permeation assembly 12 arranged in the reaction shell 11, the inside of the reaction shell 11 is divided into a dehydrogenation reaction cavity 110 and a permeation cavity 111 which are physically isolated from each other by the hydrogen permeation assembly 12; the reaction shell 11 is provided with a dehydrogenation raw material inlet, a dehydrogenation product outlet, an oxygen-containing gas inlet and a permeation cavity 111 tail gas outlet, the dehydrogenation raw material inlet and the dehydrogenation product outlet are communicated with the dehydrogenation reaction cavity 110, and the oxygen-containing gas inlet and the permeation cavity 111 tail gas outlet are communicated with the permeation cavity 111; the hydrogen permeation assembly 12 comprises a reaction layer 121 and a hydrogen permeation layer 122 arranged in sequence along a dehydrogenation path, the reaction layer 121 is filled with a dehydrogenation catalyst bed layer, the hydrogen permeation layer 122 is made of a metal or an alloy thereof, a ceramic or a molecular sieve material which has high selectivity to hydrogen, the hydrogen permeation layer 122 is a membrane structure with a porous nickel layer, and with the dehydrogenation reaction, oxygen is oxidized to form nickel oxide on the porous nickel of the hydrogen permeation layer 122, hydrogen permeated through the hydrogen permeation layer 122 is reduced with the nickel oxide, and the hydrogen and oxygen are subjected to a solid-phase oxidation-reduction reaction based on the porous nickel to provide heat required by the dehydrogenation reaction cavity 110.

[0028] In the above embodiment, the hydrogen permeation assembly 12 can divide the inside of the reaction shell 11 into the physically isolated dehydrogenation reaction cavity 110 and the permeation cavity 111, and the reaction layer 121 and the hydrogen permeation layer 122 are arranged in sequence along the dehydrogenation path, the reaction layer 121 is filled with the dehydrogenation catalyst bed layer to promote the dehydrogenation reaction, and the hydrogen permeation layer 122 is made of a material which has high selectivity to hydrogen to allow selective permeation of hydrogen.

[0029] The hydrogen generated by the dehydrogenation reaction permeates into the permeation cavity 111 under the driving of the partial pressure difference, the oxygen-containing gas is subjected to an oxidation-reduction reaction with the metal nickel on the porous nickel layer, the separated hydrogen is subjected to an oxidation-reduction reaction with the porous nickel oxide on the permeation layer (i.e. the hydrogen permeation layer 122) during the permeation process before being combined into hydrogen, heat is generated, the heat is directly provided to the hydrogen permeation layer 122, and then the heat is transmitted to the reaction layer 121 through the membrane structure of the metal, so that heat energy is provided for the continuous endothermic dehydrogenation reaction.

[0030] Meanwhile, the heat is transmitted to the permeation cavity 111 in the form of infrared radiation to heat the oxygen-containing gas, the dehydrogenation reaction is self-heat supplied, and thus the technical problem of high energy consumption and low efficiency caused by the need for external heat source in the traditional dehydrogenation reaction can be solved.

[0031] Meanwhile, oxygen reacts with hydrogen on the permeation side, and the product is water, which can reduce the pressure of hydrogen on the permeation side, increase the pressure difference between the reaction side and the permeation side, and facilitate the smooth progress of the entire dehydrogenation reaction. In addition, it can solve the problem that the exothermic reaction of oxygen and dehydrogenation raw materials on the reaction side is uncontrollable and easy to produce unsaturated products such as olefins and styrene, and then cause oxidation side reactions. In addition, it can also solve the problem that the oxidation exothermic process is easy to cause local high temperature or temperature fluctuation, which aggravates the cracking, isomerization and catalyst carbon deposition of raw materials and products, and the generated water vapor also destroys the structure of the dehydrogenation catalyst or causes the inactivation of the active component. Moreover, the present embodiment does not need to additionally add a separation process to treat CO, and other by-products, thereby reducing the separation cost and energy consumption.

[0032] Based on the above embodiment, a feasible implementation manner is proposed, characterized in that the hydrogen permeable layer 122 further comprises one of a palladium alloy film, a palladium-yttrium alloy film, a palladium-silver alloy film, a porous composite ceramic film and an iron-based alloy hollow fiber film or a SAPO-34 molecular sieve film arranged between the reaction layer 121 and the porous nickel layer. In this way, the present application can allow only hydrogen to efficiently permeate through the above-mentioned materials with high selectivity and permeability, and ensure that the hydrogen passing through is in a free state and first reacts with the nickel oxide on the porous nickel layer. Thus, it is beneficial to solve the technical problems that ordinary membrane materials have poor selectivity and may cause other gases to permeate, and that the existing hydrogen permeable membrane and oxygen permeable membrane can only form an oxidation-reduction reaction between hydrogen and oxygen. Moreover, the above-mentioned metal film structure can conduct heat and directly transfer the heat generated during the hydrogen-oxygen reduction reaction on the membrane body to the reaction layer 121, thereby heating the reaction layer 121 and providing the required heat for the reaction of the dehydrogenation reaction chamber 110.

[0033] In addition to the above feasible embodiments, in order to make the reaction process of the whole self-heat supply device more smooth, in a more preferred embodiment, the dehydrogenation reaction self-heat supply device based on the hydrogen permeation membrane reactor further comprises a temperature control system, the temperature control system comprises a temperature sensor, a flow regulating valve and a controller, wherein the temperature sensor is arranged in the dehydrogenation reaction cavity 110 and the permeation cavity 111; the flow regulating valve is connected with the oxygen-containing gas inlet; and the controller is in communication connection with the temperature sensor and the flow regulating valve, so as to adjust the feed flow of the oxygen-containing gas in real time according to the temperature feedback of the dehydrogenation reaction cavity 110, so as to control the heat release rate of the hydrogen-oxygen reduction reaction. In this embodiment, the temperature sensor arranged can monitor the reaction temperature in real time, and the controller can adjust the feed flow of the oxygen-containing gas according to the temperature data feedback to control the flow regulating valve, so as to accurately control the heat release rate of the hydrogen-oxygen reduction reaction, realize the stable control of the reaction temperature, and thus can maintain the reaction in the optimal temperature range and avoid the temperature fluctuation to cause the reaction efficiency to decrease or the catalyst to be deactivated, so as to solve the technical problems that the dehydrogenation reaction is sensitive to the temperature and the traditional control mode is difficult to adjust the heat supply in real time.

[0034] Based on the above embodiments, a feasible embodiment is proposed, the dehydrogenation reaction self-heat supply device based on the hydrogen permeation membrane reactor further comprises an auxiliary heating system, the auxiliary heating system is an electric heating wire embedded in the reactor wall, an electromagnetic induction coil wound on the outside of the reactor or a start-up burner in communication with the outside of the reactor, which is used to provide supplemental heat when the device starts, the load fluctuates or the hydrogen permeation membrane side heat supply is insufficient. In specific implementation, the above structure can ensure that the reactor quickly reaches the operating temperature or maintains stable operation, realizes the rapid start and adaptation to load changes of the reactor, achieves the technical effects of improving the reliability and operation flexibility of the device, and is beneficial to solve the technical problems that the self-heat supply system is insufficient in heat when starting or fluctuating, causing the reaction to be interrupted or the efficiency to be reduced.

[0035] Based on the above embodiments, a feasible embodiment is proposed, the dehydrogenation catalyst in the dehydrogenation reaction cavity 110 is one of a supported Pt-Sn catalyst, a catalyst or a catalyst. The permeation cavity 111 is filled with a hydrogen oxidation catalyst, which is a supported platinum or palladium catalyst. The catalysts in the above adjacent cavities cooperate with each other, the dehydrogenation catalyst efficiently catalyzes the dehydrogenation reaction to generate hydrogen and olefins or aromatic hydrocarbons, and the hydrogen oxidation catalyst promotes the rapid oxidation of hydrogen and oxygen in the permeation cavity 111 to release heat, realizes the synergistic performance of the dehydrogenation and oxidation reduction reactions, improves the reaction rate and heat generation efficiency, and achieves the technical effects of optimizing the reaction kinetics and energy utilization.

[0036] Based on the same inventive concept, another object of the present application is to provide a dehydrogenation reaction self-heat supply method, which adopts the dehydrogenation reaction self-heat supply device based on the hydrogen permeation membrane reactor as described above, and comprises the following steps: S1, preheat the reactor as a whole to above the starting temperature of the dehydrogenation reaction; S2, introduce the alkane or aromatic hydrocarbon derivative raw material into the dehydrogenation reaction cavity 110, so that it undergoes dehydrogenation reaction under the action of the dehydrogenation catalyst to generate a mixture containing olefin or aromatic hydrocarbon products and hydrogen; S3, the hydrogen generated in the dehydrogenation reaction cavity 110 selectively permeates into the permeation cavity 111 under the driving of the partial pressure difference; S4, introduce oxygen-containing gas into the permeation cavity 111, and the hydrogen and oxygen undergo redox reaction based on the porous nickel layer to release heat, and the hydrogen permeation assembly 12 and the reactor wall transfer heat to the dehydrogenation reaction cavity 110 to provide heat energy for the continuous dehydrogenation endothermic reaction; S5, collect the product mixture rich in olefins or aromatic hydrocarbons from the dehydrogenation product outlet of the dehydrogenation reaction cavity 110; and discharge the tail gas mainly containing water vapor from the tail gas outlet of the permeation cavity 111.

[0037] Compared with the prior art, the above-mentioned embodiment preheats the reactor as a whole to above the starting temperature of the dehydrogenation reaction, introduces the alkane or aromatic hydrocarbon derivative raw material into the dehydrogenation reaction cavity 110 to undergo dehydrogenation reaction, hydrogen selectively permeates into the permeation cavity 111 under the driving of the partial pressure difference, and based on the porous nickel layer, it undergoes redox exothermic reaction with the introduced oxygen-containing gas, and the heat is transferred back to the dehydrogenation reaction cavity 110 and heats the oxygen-containing gas in the permeation cavity 111. Combined with the separation effect of the hydrogen permeation membrane and the exothermic characteristics of the redox reaction, the self-heating cycle of the dehydrogenation reaction and the pressure reduction process on the hydrogen permeation side are realized, without the need for external heat source, reducing energy consumption and simplifying operation. In addition, in the specific implementation process, oxygen reacts with hydrogen to form water, which can reduce the pressure of hydrogen on the permeation side, facilitate the smooth progress of the entire dehydrogenation reaction, and solve the problem that the exothermic reaction of oxygen with the dehydrogenation raw material is uncontrollable and easy to cause oxidation side reactions of unsaturated products such as olefins and styrene when oxygen is located on the reaction side. In addition, since the controllability of the traditional reaction of oxygen with the dehydrogenation raw material is poor, the oxygen in this application only reacts with hydrogen, which can also solve the problem that the oxidation exothermic process easily causes local high temperature or temperature fluctuation, aggravates the cracking, isomerization and catalyst coking of the raw material and product, and the generated water vapor and hydrogen can also destroy the structure of the dehydrogenation catalyst or cause the deactivation of the active component. Without adding separation process to treat CO, and other by-products, the separation cost and energy consumption are reduced.

[0038] Based on the above embodiment, a feasible implementation is proposed, specifically, the S4 step in the above also includes the following steps: S401, real-time monitoring of the dehydrogenation reaction cavity 110 temperature, and precisely controlling the exothermic rate of the permeation cavity 111 by adjusting the feed flow of the oxygen-containing gas, so that the operating temperature of the dehydrogenation reaction cavity 110 is stably maintained between 500-650℃. Of course, according to the specific dehydrogenation requirements, the reaction temperature is stably maintained in the target interval of 500-800℃, and the temperature fluctuation is controlled within ±5℃. Compared with the local overheating of electric heating and the temperature unevenness of open flame heating, the hydrogen-oxygen reduction reaction of the present application avoids the side reactions such as olefin oxidation, raw material cracking and catalyst carbon deposition caused by abnormal temperature, and the selectivity of the target product is improved by 5%-10%; the water vapor or carbon dioxide generated on the permeation side can be directly discharged as clean exhaust, and will not enter the dehydrogenation reaction side, thereby protecting the structure of the reaction layer 121 and prolonging the service life of the catalyst.

[0039] Based on the above embodiment, a feasible implementation is proposed, the hydrogen partial pressure difference between the two sides of the hydrogen permeation assembly 12 is maintained at 0.1-0.5 MPa, to ensure that the hydrogen has an economically feasible permeation rate. By controlling the reaction conditions such as feed pressure and composition, the hydrogen is driven to permeate efficiently, so that the hydrogen has a better economically applicable permeation rate, and the self-supply heat cycle is ensured to continue.

[0040] Based on the above embodiment, a feasible implementation is proposed, the oxygen-containing gas is air, oxygen-enriched air or pure oxygen; the molar ratio of the amount of oxygen introduced into the permeation cavity 111 to the amount of hydrogen permeated (nO2 / nH2) / ) is between 0.5 and 1.2, to ensure sufficient reaction of the hydrogen and avoid potential oxidation damage to the membrane material by excessive oxygen. By selecting a suitable oxygen-containing gas and ratio, the hydrogen is ensured to be fully combusted to generate water vapor or condensed water, while avoiding oxidation damage to the membrane material by excessive oxygen, so that the redox reaction is efficiently and safely carried out, the heat generation efficiency is improved, and the membrane material is protected.

[0041] Based on the above embodiment, a feasible implementation is proposed, the dehydrogenation reaction self-supply heat method is applicable to any one of ethylbenzene dehydrogenation to styrene, propane dehydrogenation to propylene, and isobutane dehydrogenation to isobutene.

[0042] As set forth above, in combination with the universality of the self-supply heat device and method, the heat energy is provided for various dehydrogenation reactions through the hydrogen permeation membrane separation and the exothermic mechanism of redox, based on the above solid-phase reaction, the energy-saving and efficient production of various dehydrogenation reactions is realized, thereby widening the application range and improving the industrial applicability, and solving the technical problems of specific heating conditions required by different dehydrogenation reactions and low energy efficiency of traditional methods.

[0043] It should be noted that in the construction of the transmembrane hydrogen partial pressure difference, the feed side pressure is usually increased or the permeation side pressure is reduced to enhance the driving force. In the permeation side, the common means of reducing the pressure includes vacuum pumping and introducing purge gas, but both methods have obvious defects: vacuum pumping has high energy consumption, and the hydrogen brought by the purge gas is difficult to recover and utilize, causing resource waste.

[0044] To solve the above problems, the solution provided by the present application is to introduce air into the permeation side, so that the permeated hydrogen reacts with oxygen based on the solid phase redox reaction of metal nickel. On the one hand, the heat released by the hydrogen-oxygen reduction reaction can be fully utilized for heating, and on the other hand, the hydrogen in the permeation side can be quickly removed, thereby continuously maintaining a larger hydrogen partial pressure difference and strengthening the separation driving force.

[0045] In summary, compared with other existing reaction coupling technologies, the oxygen introduced by the dehydrogenation reaction self-heating device in the present application can react with the porous nickel layer of the membrane to generate nickel oxide. In this reaction process, oxygen first oxidizes the porous nickel on the surface of the membrane into nickel oxide, and then the hydrogen atoms permeated in the metal phase diffusion process directly reduce the nickel oxide to metal nickel. Compared with the existing hydrogen permeation process in the membrane (dissociated into hydrogen atoms on the reaction side, diffused to the permeation side in the metal lattice, and combined into hydrogen molecules). In the present embodiment, the hydrogen atoms permeated in the metal phase diffusion process directly reduce the nickel oxide to metal nickel. Hydrogen and oxygen do not react in a simple gaseous form, but through a solid phase reaction path. That is, the hydrogen atoms in the metal phase reduce the nickel oxide, and this reaction mechanism eliminates the step of combining hydrogen atoms into hydrogen molecules, and the solid phase reaction is superior to the gas phase reaction due to high material density and fast reaction rate, thereby significantly improving the separation and reaction efficiency of the entire reactor.

[0046] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A self-heating device for dehydrogenation reaction based on a hydrogen-permeable membrane reactor, characterized by comprising: The device comprises: a reactor body (1) comprising a reaction shell (11) and a hydrogen-permeable assembly (12) arranged in the reaction shell (11), the inside of the reaction shell (11) is divided into a dehydrogenation reaction cavity (110) and a permeation cavity (111) by the hydrogen-permeable assembly (12), and the dehydrogenation reaction cavity (110) and the permeation cavity (111) are physically isolated from each other; the reaction shell (11) is provided with a dehydrogenation raw material inlet, a dehydrogenation product outlet, an oxygen-containing gas inlet, and a permeation cavity (111) tail gas outlet, the dehydrogenation raw material inlet and the dehydrogenation product outlet communicate with the dehydrogenation reaction cavity (110), and the oxygen-containing gas inlet and the permeation cavity (111) tail gas outlet communicate with the permeation cavity (111); the hydrogen-permeable assembly (12) comprises a reaction layer (121) and a hydrogen-permeable layer (122) arranged in sequence along a dehydrogenation path, the reaction layer (121) is filled with a dehydrogenation catalyst bed, and the hydrogen-permeable layer (122) is a membrane structure with a porous metal layer; as the dehydrogenation reaction proceeds, oxygen reacts with the porous nickel on the hydrogen-permeable layer (122) to form nickel oxide, hydrogen permeating through the hydrogen-permeable layer (122) reacts with the nickel oxide, and hydrogen and oxygen undergo a solid-phase oxidation-reduction reaction based on the porous nickel to provide heat required for the dehydrogenation reaction cavity (110).

2. The hydrogen permeation membrane reactor based dehydrogenation reaction self-heat generating apparatus according to claim 1, characterized by, The hydrogen permeable layer (122) further comprises a palladium alloy film, a palladium yttrium alloy film, a palladium silver alloy film, a porous one of a composite ceramic membrane and an iron-based alloy hollow fiber membrane or a SAPO-34 molecular sieve membrane.

3. The hydrogen permeation membrane reactor based dehydrogenation reaction autothermal unit of claim 1, wherein, The dehydrogenation reaction self-heating device based on the hydrogen-permeable membrane reactor further comprises a temperature control system, and the temperature control system comprises: a temperature sensor arranged in the dehydrogenation reaction cavity (110) and the permeation cavity (111); a flow regulating valve connected with the oxygen-containing gas inlet; a controller in communication connection with the temperature sensor and the flow regulating valve, so as to adjust the feed flow of the oxygen-containing gas in real time according to the temperature feedback of the dehydrogenation reaction cavity (110), and control the heat release rate of the hydrogen-oxygen reduction reaction.

4. The hydrogen permeation membrane reactor based dehydrogenation reaction autothermal unit of claim 3, wherein, The dehydrogenation reaction self-heating device based on the hydrogen-permeable membrane reactor further comprises an auxiliary heating system, which is an electric heating wire embedded in the reactor wall, an electromagnetic induction coil wound on the outside of the reactor, or a start-up burner in communication with the outside of the reactor, and is used to provide supplemental heat when the device is started, the load fluctuates, or the hydrogen-permeable membrane side is insufficient.

5. The hydrogen permeation membrane reactor based dehydrogenation reaction autothermal unit of claim 1, wherein, The dehydrogenation catalyst of the dehydrogenation reaction chamber (110) is a supported Pt-Sn catalyst, or a catalyst of the formula ; the permeation chamber (111) is filled with a hydrogen oxidation catalyst, which is a supported platinum or palladium catalyst.

6. A self-heating method of dehydrogenation reaction using the self-heating device for dehydrogenation reaction based on a hydrogen-permeable membrane reactor according to any one of claims 1 to 5, characterized by, The method comprises the following steps: S1, preheating the whole reactor to above the starting temperature of the dehydrogenation reaction; S2, introducing an alkane or aromatic hydrocarbon derivative raw material into the dehydrogenation reaction cavity (110) to generate a mixture containing olefin or aromatic hydrocarbon products and hydrogen under the action of the dehydrogenation catalyst; S3, the hydrogen generated in the dehydrogenation reaction cavity (110) selectively permeates through the hydrogen-permeable membrane into the permeation cavity (111) under the driving of the partial pressure difference; S4, introducing an oxygen-containing gas into the permeation cavity (111), and hydrogen and oxygen undergo an oxidation-reduction reaction based on the porous nickel layer to release heat, and the hydrogen-permeable assembly (12) and the reactor wall transfer heat to the dehydrogenation reaction cavity (110) to provide heat energy for the continuous dehydrogenation endothermic reaction; S5, collecting the product mixture rich in olefins or aromatic hydrocarbons from the dehydrogenation product outlet of the dehydrogenation reaction cavity (110); and discharging the tail gas mainly containing water vapor from the tail gas outlet of the permeation cavity (111).

7. The self-heating dehydrogenation reaction method according to claim 6, wherein The step S4 further comprises the following steps: S401、real-time monitoring of dehydrogenation reaction cavity (110) temperature, by adjusting the feed flow of oxygen-containing gas to accurately control the exothermic rate of hydrogen-oxygen reduction reaction, so that the operating temperature of the dehydrogenation reaction cavity (110) is stably maintained between 500℃ and 650℃.

8. The self-heating reaction method of claim 7, wherein the dehydrogenation reaction is represented by the following formula: ###0002### 8 The hydrogen gas partial pressure difference between the two sides of the hydrogen permeation assembly (12) is maintained at 0.1MPa to 0.5MPa to ensure that the hydrogen gas has an economically viable permeation rate.

9. The self-heating reaction method of claim 6, wherein the dehydrogenation reaction is represented by the following formula: ###0001### 9 The oxygen-containing gas is air, oxygen-enriched air, or pure oxygen; the molar ratio of the amount of oxygen introduced into the permeation chamber (111) to the amount of hydrogen permeated is ( / The concentration should be between 0.5 and 1.2 to ensure complete combustion of hydrogen and avoid potential oxidative damage to the membrane material from excessive oxygen.

10. The self-heating dehydrogenation reaction method according to claim 6, wherein The self-heating dehydrogenation reaction method is suitable for any one of ethylbenzene dehydrogenation to styrene, propane dehydrogenation to propylene, and isobutane dehydrogenation to isobutene.

Images