A coupling system and process of propane carbon dioxide oxidative dehydrogenation and chemical looping combustion

Abstract

The application discloses a coupling system and process of propane carbon dioxide oxidative dehydrogenation and chemical chain combustion, wherein the coupling system of propane carbon dioxide oxidative dehydrogenation and chemical chain combustion comprises a reaction unit for propane dehydrogenation, a cold box unit and a separation unit; the reaction unit comprises a chemical chain combustion reaction unit, an air outlet and a carbon dioxide mixed gas outlet; a dehydrogenation reactor comprising a fixed bed reactor, a raw material inlet and a product outlet, the product outlet being communicated with the cold box unit, and the raw material inlet being communicated with the carbon dioxide mixed gas outlet; a heat exchange unit arranged on the raw material inlet and communicated with the air outlet, used for fixed bed reactor bed layer heating regeneration and / or raw material and air heat exchange. The application effectively improves the heat recovery efficiency through the optimized heating mechanism, and can better reduce the energy loss in the preparation of the same content of propylene.

Description

Technical Field

[0001] This invention relates to the field of propane oxidative dehydrogenation technology, specifically to a propane carbon dioxide oxidative dehydrogenation coupled system and process with chemical looping combustion. Background Technology

[0002] Propane dehydrogenation, an important chemical conversion process, aims to convert propane into high-value propylene. However, traditional direct propane dehydrogenation reactions suffer from thermodynamic limitations and equilibrium constraints. Furthermore, the reaction process is prone to coking, further affecting catalyst activity and lifetime. To overcome these challenges, researchers have proposed an innovative strategy: introducing carbon dioxide into the propane oxidative dehydrogenation reaction and coupling it with a reverse water-gas shift (RWGS) reaction. Utilizing the reducing properties of carbon dioxide, it reacts with propane under the action of a catalyst, producing propylene while releasing hydrogen and eliminating coking. The RWGS reaction further promotes the conversion of carbon dioxide, which not only helps drive the reaction towards propylene production but also achieves carbon recycling and reduces carbon emissions.

[0003] However, the high costs of carbon dioxide capture, purification, and transportation increase production costs. Furthermore, current propane dehydrogenation processes typically employ a process provided by Lummus Technology. This process utilizes a dual-furnace configuration—a feed heater and a reactor air heater—to maintain the efficient operation of the fixed-bed adiabatic reactor. While this design effectively controls the reaction temperature, it also generates two independent high-temperature flue gas emissions, increasing system complexity and limiting overall energy efficiency due to the potential for dew point corrosion and heat recovery challenges associated with the flue gas. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the high energy consumption of the conventional Lummus propane dehydrogenation process, and to provide a propane carbon dioxide oxidative dehydrogenation and chemical looping combustion coupling system and process to solve the above problems.

[0005] A coupling system for propane carbon dioxide oxidative dehydrogenation and chemical looping combustion includes a reaction unit for propane dehydrogenation, a cold box unit, and a separation unit; the reaction unit includes:

[0006] The chemical looping combustion reaction unit includes a carbon feedstock inlet, an oxygen feedstock inlet, an air outlet, and a carbon dioxide mixture outlet;

[0007] The dehydrogenation reactor includes a fixed-bed reactor, a feed inlet, and a product outlet. The product outlet is connected to a cold box unit, and the feed inlet is connected to a carbon dioxide mixed gas outlet.

[0008] A heat exchange unit, located at the feed inlet and connected to the air outlet, is used for bed heating and regeneration in a fixed-bed reactor and / or for heat exchange between the feed and air.

[0009] The chemical looping combustion reaction unit includes:

[0010] An air reactor includes an oxygen feedstock inlet, a solid oxygen carrier material inlet, and an oxygen-enriched carrier mixing outlet.

[0011] The first separation unit includes an oxygen-enriched carrier outlet, an air outlet, and an inlet connected to the oxygen-enriched carrier mixing outlet.

[0012] The combustion reactor includes a carbon feedstock inlet, an oxygen-deficient carrier mixing outlet, and an inlet connected to the oxygen-enriched carrier outlet.

[0013] The second separation unit includes an oxygen-deficient carrier outlet, a carbon dioxide mixed gas outlet, and an inlet connected to the oxygen-deficient carrier mixed gas outlet; the oxygen-deficient carrier outlet is connected to the solid oxygen carrier material inlet.

[0014] The solid oxygen carrier material is a metal and / or a metal oxide (Me and / or MeOx); the metal element in the metal and / or metal oxide is a transition metal element, and Me is selected from one or more elements such as titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn).

[0015] The carbon dioxide mixture outlet is connected to a carbon dioxide separation unit for separating and obtaining high-purity carbon dioxide.

[0016] The present invention also includes a waste heat boiler unit connected to an air outlet via a heat exchange unit, wherein the oxygen feedstock is processed by the waste heat boiler unit and then enters the oxygen feedstock inlet of the chemical looping combustion reaction unit.

[0017] The cold box unit is also equipped with a pressure swing adsorption unit that separates pure hydrogen and PSA tail gas at the tail gas outlet. The PSA tail gas enters the carbon feedstock inlet of the chemical loop combustion reaction unit.

[0018] The separation unit includes a propylene outlet, a circulating propane outlet, and an ethane stripper tail gas outlet.

[0019] The tail gas outlet of the ethane removal tower is connected to the carbon feed inlet of the chemical loop combustion reaction unit, and / or the circulating propane outlet is connected to the feed inlet of the dehydrogenation reactor.

[0020] The inlets of the heat exchange unit connected to the raw material inlet are respectively set as a propane inlet and a carbon dioxide inlet. A pretreatment unit is connected to the propane inlet, and the circulating propane outlet of the separation unit is connected to the propane inlet through the pretreatment unit.

[0021] The coupling methods using the above-mentioned coupling system include:

[0022] Propane feedstock and carbon dioxide produced by the chemical loop combustion reaction unit exchange heat with the high-temperature air produced by the chemical loop combustion reaction unit before entering the dehydrogenation reactor to carry out the propane oxidative dehydrogenation reaction to obtain a mixed product containing propylene. The mixed product is then cooled by the cold box unit and purified by the separation unit to obtain the target product propylene.

[0023] The process of generating carbon dioxide and high-temperature air in the chemical looping combustion reaction unit is as follows: solid oxygen carrier material and oxygen feedstock enter the air reactor together to form an oxygen-enriched carrier mixture. The oxygen-enriched carrier mixture enters the first separation unit for solid-gas separation, obtaining oxygen-enriched carrier and high-temperature air respectively. The high-temperature air is discharged from the air outlet. The oxygen-enriched carrier enters the combustion reactor and reacts with the carbon source introduced through the carbon feedstock inlet to generate an oxygen-deficient carrier mixture of carbon dioxide and anoxic carrier. The oxygen-deficient carrier mixture is introduced into the second separation unit for solid-gas separation, obtaining anoxic carrier and carbon dioxide respectively. The carbon dioxide is discharged from the carbon dioxide mixture outlet. The anoxic carrier is returned to the air reactor for recycling.

[0024] And / or, propane and carbon dioxide under pressure conditions of -0.1 to 0 MPaG, 550 ～ The dehydrogenation reaction was carried out at a temperature of 650℃, with a molar ratio of carbon dioxide to propane of 1:8. ～ 1:2.

[0025] The technical solution of this invention has the following advantages:

[0026] 1. The propane carbon dioxide oxidative dehydrogenation and chemical looping combustion coupling system provided by this invention directly utilizes the high-temperature air discharged from the air outlet of the chemical looping combustion reaction unit to heat and regenerate the bed of the fixed-bed reactor and exchange heat with the feedstock entering the dehydrogenation reactor through the feedstock inlet. The high-temperature air after heat exchange can be reduced to 60-80°C. Simultaneously, the carbon dioxide generated by the chemical looping combustion reaction unit at a certain temperature is directly used as feedstock in the dehydrogenation reactor, thereby optimizing the energy coupling heating mechanism of this invention. The optimized heating mechanism in this invention effectively improves heat recovery efficiency, ensuring better reduction of energy loss in the preparation of the same propylene content.

[0027] Specifically, under the same conditions, the increased propane conversion rate and the increased demand for carbon dioxide in this invention lead to a 1.3-1.4 times higher natural gas consumption compared to the conventional Lummus process. However, this increase is offset by a higher level of energy efficiency. Specifically, using the optimized energy-coupled heating mechanism of this invention, the heat utilization rate is improved from 80%-85% to 90%-95% when producing the same mass of propylene, while heat loss is reduced by 2.1 to 2.3 times compared to the conventional Lummus process, significantly enhancing energy efficiency. Compared to the traditional Lummus propane dehydrogenation process, this invention demonstrates superior technical performance and economic benefits, opening up new pathways for the development of propane dehydrogenation.

[0028] 2. In the coupling system of this invention, the captured high-purity carbon dioxide is used as a weak oxidant to participate in the propane oxidative dehydrogenation reaction, which significantly improves the conversion rate of propane, effectively removes carbon deposits on the catalyst surface, enhances the stability of the reaction system, extends the service life of the catalyst, and reduces production costs.

[0029] 3. The coupling system of this invention combines a chemical looping combustion reaction unit with propane dehydrogenation, introducing carbon dioxide as a reactant into the propane oxidative dehydrogenation reaction, thereby achieving zero carbon dioxide emissions. Combined with chemical looping combustion technology, it forms a closed-loop carbon cycle system, which is in line with the concept of green industrial development.

[0030] 4. This invention effectively reduces NOx generation by combining chemical loop combustion reaction with propane dehydrogenation reaction, and fully recovers and utilizes the heat of high-temperature flue gas, thereby improving energy efficiency. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the coupling system in this invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1-Reaction unit, 2-Cold box unit, 3-Separation unit, 4-Pressure swing adsorption unit, 5-Pretreatment unit;

[0035] 101-Air reactor, 102-First separation unit, 103-Combustion reactor, 104-Second separation unit, 105-Carbon dioxide separation unit, 106-Heat exchange unit, 107-Dehydrogenation reactor, 108-Waste heat boiler unit. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] Example 1

[0041] The coupling system of propane carbon dioxide oxidative dehydrogenation and chemical looping combustion, such as Figure 1 As shown, the system includes a reaction unit 1 for propane dehydrogenation, a cold box unit 2, and a separation unit 3. The reaction unit 1 includes a chemical looping combustion reaction unit, a dehydrogenation reactor 107, and a heat exchange unit 106. The chemical looping combustion reaction unit includes a carbon feed inlet, an oxygen feed inlet, an air outlet, and a carbon dioxide mixed gas outlet. The dehydrogenation reactor 107 includes a feed inlet and a product outlet. The product outlet is connected to the cold box unit 2, and the feed inlet is connected to the carbon dioxide mixed gas outlet. The heat exchange unit 106 is located on the feed inlet and is connected to the air outlet. It is used for bed heating and regeneration of the fixed-bed reactor and / or heat exchange between the feed and the air.

[0042] In this invention, propane feedstock and carbon dioxide generated by the chemical loop combustion reaction unit exchange heat with the high-temperature air generated by the chemical loop combustion reaction unit before entering the dehydrogenation reactor 107 to carry out propane oxidative dehydrogenation reaction to obtain a mixed product containing propylene. The mixed product is then cooled by the cold box unit 2 and purified by the separation unit 3 to obtain the target product propylene.

[0043] This invention directly utilizes the high-temperature air discharged from the air outlet of the chemical looping combustion reaction unit to heat and regenerate the bed of the fixed-bed reactor and to heat the feedstock entering the dehydrogenation reactor through the feedstock inlet. Furthermore, it directly uses carbon dioxide generated at a certain temperature by the chemical looping combustion reaction unit as the feedstock into the dehydrogenation reactor, thereby optimizing the heating mechanism. By optimizing the heating mechanism and improving heat recovery efficiency, this invention ensures significantly reduced energy loss in the production of the same propylene content, with heat loss reduced by 2.1 to 2.3 times compared to the conventional Lummus process. Compared to the traditional Lummus propane dehydrogenation process, this invention demonstrates superior technical performance and economic benefits, opening up new pathways for the development of propane dehydrogenation.

[0044] The chemical loop combustion reaction unit comprises an air reactor 101, a first separation unit 102, a combustion reactor 103, and a second separation unit 104 forming a loop. Specifically, the air reactor 101 has an oxygen feedstock inlet, a solid oxygen carrier material inlet, and an oxygen-enriched carrier mixture outlet; the first separation unit 102 has an oxygen-enriched carrier outlet, an air outlet, and an air inlet; the combustion reactor 103 has a carbon feedstock inlet, an oxygen-deficient carrier mixture outlet, and an air inlet; and the second separation unit 104 has an oxygen-deficient carrier outlet, a carbon dioxide mixture outlet, and an air inlet. The inlet of the first separation unit 102 is connected to the oxygen-enriched carrier mixture outlet, the inlet of the combustion reactor 103 is connected to the oxygen-enriched carrier outlet, and the inlet of the second separation unit 104 is connected to the oxygen-deficient carrier mixture outlet. The solid oxygen carrier material inlet of the air reactor 101 is connected to the oxygen-deficient carrier outlet to achieve the recycling of the solid oxygen carrier material.

[0045] The specific implementation process of the chemical looping combustion reaction unit is as follows: Solid oxygen carrier material (e.g., MeOx and / or Me) and oxygen feedstock (oxygen-enriched air) are introduced into air reactor 101, so that MeOx and / or Me, with MeOx as the dominant component, form an oxygen-enriched carrier mixture in air reactor 101. The oxygen-enriched carrier mixture enters the first separation unit 102 for solid-gas separation, obtaining oxygen-enriched carrier (MeOx / Me) and high-temperature air respectively. The high-temperature air is discharged from the air outlet, and the oxygen-enriched carrier (MeOx / Me) enters the combustion reactor 103, where it reacts with the carbon source introduced through the carbon feedstock inlet to generate an oxygen-deficient carrier mixture of carbon dioxide and oxygen-deficient carrier (Me / MeOx). The oxygen-deficient carrier mixture is introduced into the second separation unit 104 for solid-gas separation, obtaining oxygen-deficient carrier (Me / MeOx) and carbon dioxide respectively. The carbon dioxide is discharged from the carbon dioxide mixture outlet, and the oxygen-deficient carrier (Me / MeOx) is returned to air reactor 101 for recycling.

[0046] In this invention, the metal and / or metal oxide (Me / MeOx) mentioned above is preferably Cu / CuO. The operating pressure of the air reactor 101 is 0. ～ 0.1 MPaG, operating temperature 800°C ～ At 900℃, the molar ratio of air to transition metal Cu / CuO is 6. ～ 8.

[0047] In this invention, the carbon feedstock can be at least one of natural gas, PSA tail gas, and deethaner tail gas. The natural gas is methane gas, the PSA tail gas includes hydrogen, methane, and carbon dioxide, and the deethaner tail gas includes hydrogen, methane, and ethane. The operating pressure of the combustion reactor 103 is 0. ～ 0.1 MPaG, operating temperature 500°C ～ At 700℃, the molar ratio of fuel gas, PSA tail gas, and deethaner tail gas to CuO / Cu is 0.1. ～ 1. This molar ratio will cause the hydrocarbons in the fuel gas to be completely converted into carbon dioxide.

[0048] In this invention, the carbon dioxide discharged from the carbon dioxide mixture outlet is used as a raw material to enter the dehydrogenation reactor 107 and combine with the propane introduced into the dehydrogenation reactor 107, at -0.1... ～ 0 MPaG pressure conditions, 550 ～ The dehydrogenation reaction was carried out at a temperature of 650℃, wherein the molar ratio of carbon dioxide to propane entering the dehydrogenation reactor 107 was 1:8. ～ At a ratio of 1:2, the above conditions achieve a better conversion rate of propane carbon dioxide oxidative dehydrogenation and a better selectivity for propylene.

[0049] The higher the purity of the carbon dioxide required in the dehydrogenation reactor 107, the better. The carbon dioxide discharged directly from the carbon dioxide mixture outlet of the chemical loop combustion reaction unit of this invention contains a high level of moisture. Therefore, it needs to be separated to obtain high-purity carbon dioxide that meets the requirements of the dehydrogenation reactor 107. Specifically, a carbon dioxide separation unit 105 is connected to the carbon dioxide mixture outlet for separating and obtaining high-purity carbon dioxide. The carbon dioxide separation unit 105 removes moisture, retaining only high-purity carbon dioxide. The high-purity carbon dioxide purified by the carbon dioxide separation unit 105 can be directly fed into the dehydrogenation reactor 107 as a raw material.

[0050] In order to maximize energy utilization, the air separated by the first separation unit 102 is extremely hot. The present invention uses the high temperature of the air to heat and regenerate the bed of the fixed bed reactor through the heat exchange unit 106, and to exchange heat with the raw materials entering the dehydrogenation reactor 107. It can exchange heat with high-purity carbon dioxide at the same time, and can also exchange heat with the propane raw material introduced into the dehydrogenation reactor 107. The raw material after heat exchange can effectively realize the recovery of waste heat in the high-temperature air, and reduce the temperature of the high-temperature air to 60-80°C.

[0051] The coupling system of the present invention also includes a waste heat boiler unit 108 connected to the air outlet via a heat exchange unit 106. After being processed by the waste heat boiler unit 108, the oxygen feedstock enters the oxygen feedstock inlet of the chemical loop combustion reaction unit. This allows the oxygen-enriched air to first utilize the waste heat of the air cooled to 60-80°C before being introduced into the air reactor 101 for use.

[0052] To better reduce exhaust emissions, the cold box unit 2 is equipped with a pressure swing adsorption unit 4 at its exhaust outlet to separate pure hydrogen and PSA exhaust gas. The PSA exhaust gas serves as the carbon feedstock for the combustion reactor 103, entering the chemical looping combustion reaction unit through the carbon feedstock inlet. Pure hydrogen can be effectively recovered and reused, thus reducing exhaust emissions. Simultaneously, the separation unit 3 includes a propylene outlet, a circulating propane outlet, and a deethaner exhaust gas outlet. The deethaner exhaust gas can also serve as the carbon feedstock for the combustion reactor 103, entering the chemical looping combustion reaction unit through the carbon feedstock inlet, further reducing exhaust emissions.

[0053] Furthermore, the circulating propane discharged from the circulating propane outlet in the separation unit 3 of the present invention can also exchange heat with the propane feedstock through the heat exchange unit 106 and then enter the dehydrogenation reactor 107 through the feedstock inlet of the dehydrogenation reactor 107 to carry out the propane dehydrogenation reaction.

[0054] The propane feedstock includes ethane, propane, and butane, while the recycled propane mainly includes propane and C4+ heavy components. To ensure conversion rate and selectivity, the propane feedstock and recycled propane first enter the pretreatment unit 5 to remove the C4+ heavy components, obtaining C3 light component gas. Therefore, in this invention, the inlets of the heat exchange unit 106 connected to the feedstock inlet are respectively set as propane inlet and carbon dioxide inlet. The pretreatment unit 5 is connected to the propane inlet, and the recycled propane outlet of the separation unit 3 is connected to the propane inlet through the pretreatment unit 5.

[0055] Comparative Example 1

[0056] The difference from Example 1 is that the conventional Lummus propane dehydrogenation process is used, that is, the chemical loop combustion reaction unit is replaced by a reaction feed heater and a reactor air heater, as detailed below:

[0057] In this comparative example, propane feedstock is heated in a reaction feed heater and then in a reactor air heater to the same temperature as in Example 1. It then enters the dehydrogenation reactor 107 to carry out the propane oxidative dehydrogenation reaction under the same parameters to obtain a mixed product containing propylene. The mixed product is then cooled in a cold box unit 2 under the same parameters as in Example 1 and purified in a separation unit 3 to obtain the target product propylene.

[0058] When producing the same quality of propylene, the natural gas consumption in Example 1 increased by 1.3-1.4 times compared to Comparative Example 1, but the heat utilization rate was improved from 80%-85% to 90%-95%. The heat loss in Example 1 was reduced by 2.1 to 2.3 times compared to Comparative Example 1, and the energy utilization efficiency was significantly enhanced.

[0059] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A coupling system for propane carbon dioxide oxidative dehydrogenation and chemical looping combustion, comprising a reaction unit (1) for propane dehydrogenation, a cold box unit (2) and a separation unit (3); characterized in that, The reaction unit (1) includes: The chemical looping combustion reaction unit includes a carbon feedstock inlet, an oxygen feedstock inlet, an air outlet, and a carbon dioxide mixture outlet; The dehydrogenation reactor (107) includes a fixed-bed reactor, a feed inlet and a product outlet. The product outlet is connected to the cold box unit (2), and the feed inlet is connected to the carbon dioxide mixed gas outlet. A heat exchange unit (106) is provided at the feed inlet and connected to the air outlet for bed heating and regeneration of the fixed-bed reactor and / or heat exchange between the feed and the air.

2. The coupling system according to claim 1, characterized in that, The chemical looping combustion reaction unit includes: Air reactor (101) includes an oxygen feedstock inlet, a solid oxygen carrier material inlet, and an oxygen-enriched carrier mixing outlet; The first separation unit (102) includes an oxygen-enriched carrier outlet, an air outlet, and an inlet connected to the oxygen-enriched carrier mixing outlet. The combustion reactor (103) includes a carbon feedstock inlet, an oxygen-deficient carrier mixing outlet, and an inlet connected to the oxygen-enriched carrier outlet; The second separation unit (104) includes an oxygen-deficient carrier outlet, a carbon dioxide mixed gas outlet, and an inlet connected to the oxygen-deficient carrier mixed gas outlet; the oxygen-deficient carrier outlet is connected to the solid oxygen carrier material inlet.

3. The coupling system according to claim 2, characterized in that, The solid oxygen carrier material is a metal and / or a metal oxide; the metal element in the metal and / or metal oxide is a transition metal element.

4. The coupling system according to any one of claims 1-3, characterized in that, The carbon dioxide mixture outlet is connected to a carbon dioxide separation unit (105) for separating and obtaining high-purity carbon dioxide.

5. The coupling system according to any one of claims 1-3, characterized in that, It also includes a waste heat boiler unit (108) connected to an air outlet via a heat exchange unit (106), and the oxygen feedstock enters the oxygen feedstock inlet of the chemical loop combustion reaction unit after being processed by the waste heat boiler unit (108).

6. The coupling system according to any one of claims 1-5, characterized in that, The cold box unit (2) is also equipped with a pressure swing adsorption unit (4) for separating pure hydrogen and PSA tail gas at the tail gas outlet. The PSA tail gas enters the carbon feedstock inlet of the chemical loop combustion reaction unit.

7. The coupling system according to any one of claims 1-5, characterized in that, The separation unit (3) includes a propylene outlet, a circulating propane outlet, and an ethane stripper tail gas outlet; The tail gas outlet of the deethaner is connected to the carbon feed inlet of the chemical loop combustion reaction unit, and / or the circulating propane outlet is connected to the feed inlet of the dehydrogenation reactor (107).

8. The coupling system according to claim 7, characterized in that, The inlets of the heat exchange unit (106) connected to the raw material inlet are respectively set as propane inlet and carbon dioxide inlet. The propane inlet is connected to a pretreatment unit (5). The circulating propane outlet of the separation unit (3) is connected to the propane inlet through the pretreatment unit (5).

9. A coupling method based on the coupling system according to any one of claims 1-8, characterized in that, include: After the propane feedstock and the carbon dioxide generated by the chemical loop combustion reaction unit exchange heat with the high-temperature air generated by the chemical loop combustion reaction unit, they enter the dehydrogenation reactor (107) to carry out the propane oxidative dehydrogenation reaction to obtain a mixed product containing propylene. The mixed product is then cooled by the cold box unit (2) and purified by the separation unit (3) to obtain the target product propylene.

10. The coupling method according to claim 9, characterized in that, The process of generating carbon dioxide and high-temperature air in the chemical loop combustion reaction unit is as follows: solid oxygen carrier material and oxygen feedstock enter the air reactor (101) together to form an oxygen-enriched carrier mixture. The oxygen-enriched carrier mixture enters the first separation unit (102) for solid-gas separation to obtain oxygen-enriched carrier and high-temperature air respectively. The high-temperature air is discharged from the air outlet. The oxygen-enriched carrier enters the combustion reactor (103) and reacts with the carbon source introduced through the carbon feedstock inlet to generate an oxygen-deficient carrier mixture of carbon dioxide and anoxic carrier. The oxygen-deficient carrier mixture is introduced into the second separation unit (104) for solid-gas separation to obtain anoxic carrier and carbon dioxide respectively. The carbon dioxide is discharged from the carbon dioxide mixture outlet. The anoxic carrier is returned to the air reactor (101) for recycling. And / or, propane and carbon dioxide at -0.1 ～ 0 MPaG pressure conditions, 550 ～ The dehydrogenation reaction was carried out at a temperature of 650℃, with a molar ratio of carbon dioxide to propane of 1:

8. ～ 1:2.

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