Propane dehydrogenation reaction system and propane dehydrogenation reaction process

Abstract

According to the propane dehydrogenation reaction system and the propane dehydrogenation reaction process provided by the invention, the system and the process are adopted for propane dehydrogenation reaction, so that emission of carbon dioxide and wastewater can be reduced, meanwhile, a large amount of heat can be recycled, energy consumption is reduced, and the system and the process are green and environment-friendly. The system comprises a feeding heating furnace, a heat recovery unit, a reaction unit, a gas-liquid separation unit, a wastewater treatment unit and a gas-phase product post-treatment unit, the feed heating furnace is used for heating propane feed; the heat recovery unit is used for carrying out heat exchange on flue gas and a water phase and separating to obtain a first gas phase and a first liquid phase; the reaction unit is used for enabling propane feed to react with a first gas phase; the gas-liquid separation unit is used for treating the product flow and the first liquid phase to obtain a gas-phase product and oil-containing wastewater; the wastewater treatment unit is used for treating oil-containing wastewater; and the gas-phase product post-treatment unit is used for drying and cryogenic separation of the gas-phase product.

Description

Technical Field

[0001] The invention relates to the technical field of propane dehydrogenation technology, and in particular to a propane dehydrogenation reaction system and a propane dehydrogenation reaction technology. Background Art

[0002] The propane dehydrogenation reaction temperature is high and it is an endothermic reaction, so the feed propane needs to be preheated and heat needs to be continuously added during the reaction. The current mainstream processes are the UOP moving bed process and the LUMMUS fixed bed process. Both processes use a propane feed heating furnace to preheat the raw materials. UOP uses an interstage heating furnace to supplement the heat of the reaction process, while LUMMUS uses a regenerative air heating furnace to heat the regenerated air and bring the heat into the reactor, while using the heat generated by the charring process to supplement the heat for the reaction. Regardless of the heating method used, a large amount of carbon dioxide will be produced by burning fuel gas. At the same time, the heating furnace uses a naturally aspirated type to heat the nitrogen in the air at the same time, and considering the dew point corrosion problem during the exhaust process, it is necessary to exhaust the smoke at a temperature of about 110°C, which will result in a certain amount of energy waste.

[0003] Currently, all industrialized propane dehydrogenation units use direct dehydrogenation, but as the coking problem during industrial operation is difficult to solve, oxidative dehydrogenation is gradually gaining attention.

[0004] Chinese patent application CN114659374A introduces a method for utilizing flue gas from a propane dehydrogenation device. The method mainly involves redrawing the flue gas discharged from the waste heat boiler, mixing it with oxygen, and then re-entering the reactor as regeneration gas for regeneration. This method can reduce the amount of regeneration air used, while recovering part of the heat of the flue gas, which will reduce the overall energy consumption of the device. However, the flue gas recovered in this way contains a portion of NOx and water, and the recovered flue gas may cause equipment corrosion when it is lower than the dew point temperature. In addition, a regeneration air compressor is also required during the flue gas recovery process for operations such as pressurization, and the energy consumption of the device is reduced to a small extent.

[0005] Chinese patent application CN115745741A discloses a coupling system and process for synthesizing methanol by dehydrogenation of propane and hydrogenation of carbon dioxide. It obtains high-purity carbon dioxide from the flue gas of the gas boiler through a series of operations such as dehydration, desulfurization, carbon dioxide capture, and recovery, and uses the hydrogen generated by dehydrogenation to produce methanol. This method aims to reduce the carbon emissions of propane dehydrogenation, but the production route of carbon dioxide is relatively complicated, which increases the processing cost of methanol. Summary of the invention

[0006] The present invention provides a propane dehydrogenation reaction system and a propane dehydrogenation reaction process. The system and process of the present invention are used to carry out propane dehydrogenation reaction, which can reduce the emission of carbon dioxide and wastewater, and even achieve the purpose of zero emission. At the same time, a large amount of heat can be recovered, energy consumption can be reduced, and green environmental protection can be achieved.

[0007] To achieve the purpose, the present invention provides the following technical solutions:

[0008] The present invention provides a propane dehydrogenation reaction system, which includes a feed heating furnace, a heat recovery unit, a reaction unit, a gas-liquid separation unit, a wastewater treatment unit, and a gas phase product post-treatment unit;

[0009] The feed heating furnace is used to heat the propane feed by burning fuel and obtain heated propane feed and flue gas;

[0010] The heat recovery unit is used to perform heat exchange between the flue gas and the water phase obtained in the wastewater treatment unit to obtain cooled flue gas and a preheated water phase, and to perform gas-liquid separation on the cooled flue gas to obtain a first gas phase and a first liquid phase;

[0011] The reaction unit comprises a reactor for reacting the heated propane feed and the first gas phase in the presence of a catalyst to obtain a product stream comprising propylene, propane, hydrogen and carbon monoxide;

[0012] The gas-liquid separation unit is used to process the product stream and the first liquid phase to obtain a gas phase product and oily wastewater containing heavy hydrocarbons and water;

[0013] The wastewater treatment unit is used to treat the oily wastewater to obtain a water phase and an oil phase;

[0014] The gas phase product post-processing unit is used to dry and cryogenically separate the gas phase product to obtain a liquid phase C3 product and a by-product light component;

[0015] The gas phase product post-processing unit and the wastewater treatment unit are respectively connected to the feed heating furnace to feed the by-product light components and the oil phase into the feed heating furnace for use as the fuel.

[0016] Preferably, the heat recovery unit is connected to the convection section of the feed heating furnace so that the preheated water phase exchanges heat with the flue gas flowing through the convection section to obtain steam.

[0017] Preferably, the fume outlet of the feed heating furnace is connected to the fume exhaust pipe;

[0018] The heat recovery unit comprises a non-phase-change heat exchanger, a phase-change heat exchanger and a gas-liquid separation device; and along the flow direction of the flue gas in the flue gas exhaust pipe, the non-phase-change heat exchanger, the phase-change heat exchanger and the gas-liquid separation device are connected in series in sequence through the flue gas exhaust pipe;

[0019] The wastewater treatment unit is connected to a water phase delivery pipe for outputting the water phase, and the water phase delivery pipe is connected to the phase change heat exchanger, so that the water phase exchanges heat with the flue gas flowing through the phase change heat exchanger, and obtains a preliminarily preheated water phase;

[0020] The non-phase-change heat exchanger is also connected to the water phase outlet of the phase-change heat exchanger through a preliminary preheated water phase output pipeline, so that the preliminary preheated water phase exchanges heat with the flue gas flowing through the non-phase-change heat exchanger to obtain the preheated water phase;

[0021] The gas-liquid separation device is used to perform gas-liquid separation on the flue gas output by the phase change heat exchanger to obtain the first gas phase and the first liquid phase.

[0022] Preferably, the reaction unit further comprises an inlet and outlet material heat exchanger for performing heat exchange between the product stream before entering the gas-liquid separation unit and the propane feed before entering the feed heating furnace;

[0023] Preferably, the reaction unit further comprises a compressor feed cooler, which is arranged between the inlet and outlet material heat exchanger and the gas-liquid separation unit and is used to cool the product flow output by the inlet and outlet material heat exchanger before entering the gas-liquid separation unit.

[0024] Preferably, the gas-liquid separation unit comprises a multi-stage gas-liquid separation tank connected in series, and between two adjacent stages of the gas-liquid separation tanks, a compressor and an interstage cooler are sequentially arranged in series between the gas phase outlet of the upstream gas-liquid separation tank and the feed inlet of the downstream gas-liquid separation tank.

[0025] Preferably, the wastewater treatment unit comprises an emulsifier and an oil removal coalescer;

[0026] The demulsifier is used to destroy the oil-in-water structure of the oily wastewater;

[0027] The oil removal coalescer is used to process the material after being processed by the demulsifier, and separate the water phase and the oil phase.

[0028] Preferably, the gas phase product post-processing unit comprises a drying device and a cryogenic separation device;

[0029] The drying device is used to dry the gas phase product to remove water and hydrogen sulfide entrained in the gas phase product;

[0030] The cryogenic separation device is used to perform the cryogenic separation on the gas phase product after being processed by the drying device to obtain a liquid phase C3 product and the by-product light components.

[0031] The present invention also provides a process for carrying out a propane dehydrogenation reaction using the propane dehydrogenation reaction system described above, comprising the following steps:

[0032] (1) feeding propane feed into the feed heating furnace, and heating the propane feed by providing heat through combustion of fuel in the feed heating furnace to obtain heated propane feed and flue gas; preferably, the feed heating furnace uses pure oxygen for combustion support;

[0033] (2) sending the flue gas to a heat recovery unit to perform heat exchange with the water phase obtained in the wastewater treatment unit to obtain cooled flue gas and a preheated water phase; performing gas-liquid separation on the cooled flue gas to obtain a first gas phase and a first liquid phase;

[0034] (3) reacting the heated propane feed with the first gas phase in the reactor of the reaction unit in the presence of a catalyst to obtain a product stream comprising propylene, propane, hydrogen and carbon monoxide;

[0035] (4) sending the product stream and the first liquid phase into the gas-liquid separation unit for treatment to obtain a gas phase product and separate the oily wastewater containing heavy hydrocarbons and water;

[0036] The gas phase product is sent to the gas phase product post-processing unit for drying and deep cold separation to obtain a liquid phase C3 product and a by-product light component; the by-product light component is sent to the feed heating furnace of step (1) to be burned as fuel;

[0037] (5) The oily wastewater is sent to the wastewater treatment unit for treatment to obtain a water phase and an oil phase; the water phase is circulated to the heat recovery unit of step (2) for heat exchange; and the oil phase is sent to the feed heating furnace of step (1) for combustion as fuel.

[0038] Preferably, the method further comprises the following steps:

[0039] In step (2), the preheated water phase is sent to the convection section of the feed heating furnace to exchange heat with the flue gas, so that the preheated water phase is converted into steam;

[0040] And / or, in step (2), in the heat recovery unit, the flue gas is passed through a non-phase change heat exchanger and a phase change heat exchanger in sequence, and then enters a gas-liquid separation device for gas-liquid separation to obtain the first gas phase and the first liquid phase; in the phase change heat exchanger, the flue gas is heat exchanged with the water phase obtained in the wastewater treatment unit to obtain a pre-heated water phase; in the non-phase change heat exchanger, the flue gas is heat exchanged with the pre-heated water phase to obtain the pre-heated water phase;

[0041] And / or, in step (1), the propane feed to be fed into the feed heating furnace is preliminarily heat exchanged with the product stream output from the reactor in an inlet and outlet material heat exchanger; preferably, the product stream after heat exchange in the inlet and outlet material heat exchanger is fed into a compressor feed cooler for cooling, and then fed into the gas-liquid separation unit;

[0042] And / or, in step (5), the oily wastewater is first sent to the demulsifier of the wastewater treatment unit for demulsification, and then sent to the oil removal coalescer of the wastewater treatment unit for oil-water separation to obtain the water phase and the oil phase.

[0043] The technical solution provided by the present invention has the following beneficial effects:

[0044] (1) Compared with the prior art, the system and process of the present invention can reduce carbon dioxide and wastewater emissions by carrying out propane dehydrogenation reaction, and is a new green and low-carbon reaction process;

[0045] (2) The present invention can convert high-carbon coke substances produced by high-temperature cracking and olefin polymerization into hydrogen and carbon monoxide through partial oxidation of carbon dioxide and water-gas reaction of water, thereby improving the atomic utilization rate and avoiding the waste of energy and reaction time caused by catalyst regeneration;

[0046] (3) The present invention can effectively recover exhaust heat, further reducing the energy consumption of the device and production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A simplified flow chart of a propane dehydrogenation reaction process in one embodiment;

[0048] Figure 2 is a schematic diagram of a propane dehydrogenation reaction system in one embodiment;

[0049] Figure 3 It is a brief flow chart of the propane dehydrogenation reaction process in Comparative Example 1;

[0050] Figure 4 Schematic diagram of the propane dehydrogenation reaction system in Comparative Example 1. DETAILED DESCRIPTION

[0051] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with examples. It should be understood that the following examples are only for a better understanding of the present invention and do not mean that the present invention is limited to the following examples.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The term "and / or" as may be used herein includes any and all combinations of one or more of the related listed items. The terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

[0053] The first aspect of the present invention provides a propane dehydrogenation reaction system, see Figure 1 , Figure 2 The system mainly includes a feed heating furnace 1, a heat recovery unit 100, a reaction unit 200, a gas-liquid separation unit 300, a wastewater treatment unit 500 and a gas-phase product post-treatment unit 400.

[0054] The feed heating furnace 1 is used to provide heat by burning fuel, thereby heating the propane feed to obtain heated propane feed and flue gas; specifically, the radiation section at the lower part of the feed heating furnace 1 is used to heat the propane feed, for example, from 452° C. to 590° C.;

[0055] The heat recovery unit 100 is used to perform heat exchange between the flue gas output from the feed heating furnace 1 and the water phase obtained in the wastewater treatment unit 500, thereby obtaining cooled flue gas and preheated water phase, and also to separate the cooled flue gas into a first gas phase and a first liquid phase through gas-liquid separation; the waste heat of the flue gas is recovered and utilized by the heat recovery unit 100;

[0056] The reaction unit 200 includes a reactor 5 for reacting the heated propane feed and the first gas phase in the presence of a catalyst to obtain a product stream comprising propylene, propane, hydrogen and carbon monoxide; the main reaction of propane dehydrogenation is mainly carried out in the reactor 5;

[0057] The gas-liquid separation unit 300 is used to process the product flow output from the reactor 5 and the first liquid phase output from the heat recovery unit 100, and obtain a gas phase product through gas-liquid separation, and also obtain oily wastewater containing heavy hydrocarbons with carbon content of more than four and water;

[0058] The wastewater treatment unit 500 is used to perform oil-water separation treatment on the oily wastewater separated in the gas-liquid separation unit 300, thereby obtaining a water phase and an oil phase;

[0059] The gas phase product post-processing unit 400 is used to dry and cryogenically separate the gas phase product described in the gas-liquid separation unit 300, so as to obtain liquid phase C3 products and by-product light components; wherein the by-product light components mainly include methane, ethane, ethylene and hydrogen;

[0060] The gas phase product post-processing unit 400 and the wastewater treatment unit 500 are respectively connected to the feed heating furnace 1, and are used to send the by-product light components separated in the gas phase product post-processing unit 400 and the oil phase separated in the wastewater treatment unit 500 into the feed heating furnace 1 for use as the fuel, that is, as a source of fuel.

[0061] The system of the present invention is used to carry out propane dehydrogenation reaction. After the flue gas recovers heat in the heat recovery unit 100, the separated first gas phase is used as a raw material and enters the reactor 5 together with the propane feed for dehydrogenation reaction. The weak oxidizing property of carbon dioxide and the dilution of propane can improve the conversion rate of propane and reduce the amount of carbon deposits generated during the reaction. At the same time, the oil phase and the water phase of the oily wastewater generated during the reaction are separated by the wastewater treatment unit 500, and the by-product light components separated in the oil phase and gas phase product post-processing unit 400 are sent to the feed heating furnace 1 together as fuel. The entire process system can reduce carbon emissions and wastewater emissions from the process system through the clever arrangement and mutual coordination of each unit and each material processing flow, while reducing energy consumption and fuel consumption of the device through waste heat recovery and heavy hydrocarbon recovery. On the other hand, it can improve the reaction effect. By incorporating the first gas phase separated after flue gas waste heat recovery into the reactor 5, the occurrence of side reactions can be effectively reduced, and the selectivity and overall yield of propylene can be improved. Based on the process system, propane dehydrogenation reaction is carried out, with less emissions of carbon dioxide, wastewater and waste oil, and full use of heat, which can greatly reduce energy consumption.

[0062] Furthermore, the heat recovery unit 100 is connected to the convection section of the feed heating furnace 1, so that the preheated water phase obtained in the heat recovery unit 100 is heat exchanged with the flue gas flowing through the convection section of the feed heating furnace 1, and the preheated water phase is heated and converted into steam, which can be used by the separation system of the device.

[0063] Furthermore, the smoke outlet of the feed heating furnace 1 is connected to the smoke exhaust pipe 20 , and the smoke in the feed heating furnace 1 is output to the outside through the smoke exhaust pipe 20 . The heat recovery unit 100 preferably includes a non-phase change heat exchanger 2, a phase change heat exchanger 3 and a gas-liquid separation device 4; and along the flue gas flow direction in the flue gas exhaust pipe 20, the non-phase change heat exchanger 2, the phase change heat exchanger 3 and the gas-liquid separation device 4 are connected in series in sequence through the flue gas exhaust pipe 20; the wastewater treatment unit 500 is connected to a water phase conveying pipe for outputting a water phase, and the water phase conveying pipe is connected to the phase change heat exchanger 3, so that the water phase is heat exchanged with the flue gas flowing through the phase change heat exchanger 3, thereby obtaining a preliminarily preheated water phase and further cooled flue gas; the non-phase change heat exchanger 2 is also connected to the water phase outlet of the phase change heat exchanger 3 through a preliminarily preheated water phase output pipeline 21, so that the preliminarily preheated water phase is heat exchanged with the flue gas flowing through the non-phase change heat exchanger 2, thereby obtaining a preheated water phase and a preliminarily cooled flue gas; the gas-liquid separation device 4 is connected to the flue gas outlet of the phase change heat exchanger 3, and is used to perform gas-liquid separation on the flue gas output by the phase change heat exchanger 3 to obtain a first gas phase and a first liquid phase. By allowing the flue gas to flow through the non-phase change heat exchanger 2 and the phase change heat exchanger 3 in sequence to fully recover the flue gas heat, and to preheat the circulating water to fully recover the flue gas heat, the thermal efficiency of the feed heating furnace 1 can be improved. One is a non-phase change heat exchanger 2, which is used to fully recover the heat of the flue gas while avoiding the dew point corrosion problem caused by water liquefaction, and can reduce the material grade of the heat exchanger, thereby reducing investment. The other is a phase change heat exchanger 3, which is used to fully recover the phase change heat of water vapor in the flue gas. At the same time, the water liquefaction process removes nitrogen and sulfur oxides in the flue gas to avoid subsequent corrosion to the reactor 5.

[0064] Preferably, the reaction unit 200 further includes an inlet and outlet material heat exchanger 6, through which the product flow before entering the gas-liquid separation unit 300 is heat exchanged with the propane feed before entering the feed heating furnace 1, so that the heat in the system is further utilized and energy consumption is reduced. Preferably, the reaction unit 200 further includes a compressor feed cooler 7, which is arranged between the inlet and outlet material heat exchanger 6 and the gas-liquid separation unit 300, and is used to cool the product flow after heat exchange through the inlet and outlet material heat exchanger 6 before entering the gas-liquid separation unit 300.

[0065] Preferably, the gas-liquid separation unit 300 comprises multi-stage gas-liquid separation tanks 8, 11, 13 connected in series, and between two adjacent gas-liquid separation tanks, a compressor 9 and an interstage cooler 10 are sequentially connected in series between the gas phase outlet of the upstream gas-liquid separation tank and the feed inlet of the downstream gas-liquid separation tank. Figure 2For example, a primary gas-liquid separation tank 8, a secondary gas-liquid separation tank 11 and a tertiary gas-liquid separation tank 13 are provided, and a compressor 9 and an interstage cooler 10 are provided in series between the gas phase outlet of the primary gas-liquid separation tank 8 and the feed inlet of the secondary gas-liquid separation tank 11; similarly, a compressor 9 and an interstage cooler 10 are provided in series between the gas phase outlet of the secondary gas-liquid separation tank 11 and the feed inlet of the tertiary gas-liquid separation tank 13. The oily wastewater containing heavy hydrocarbons and water separated from the gas-liquid separation tanks at each level is sent to the wastewater treatment unit 500, and the gas phase product separated from the tertiary gas-liquid separation tank 13 enters the gas phase product post-processing unit 400 for further processing. By providing the compressor 9, the drying effect of the subsequent drying device 14 can be improved by increasing the pressure, and at the same time, a certain convenience is provided for the processing of the subsequent deep-cold separation device 15.

[0066] Preferably, the wastewater treatment unit 500 includes a demulsifier 16 and an oil removal coalescer 17; the demulsifier 16 is used to destroy the water-in-oil structure of the oily wastewater; the oil removal coalescer 17 is used to process the material treated by the demulsifier 16, and separate the water phase and the oil phase, wherein the water phase is sent to the heat recovery unit 100 for heat exchange with the flue gas, and then enters the convection section of the feed heating furnace 1 for further heating and conversion into steam, and the oil phase is sent to the feed heating furnace 1 as fuel for use.

[0067] Preferably, the gas phase product post-processing unit 400 includes a drying device 14 and a cryogenic separation device 15. Among them, the drying device 14 is used to dry the gas phase product obtained in the gas-liquid separation unit 300, so as to remove the water and hydrogen sulfide entrained in the gas phase product; the cryogenic separation device 15 is used to perform cryogenic separation on the gas phase product after being treated by the drying device 14, and separate the liquid phase carbon three product and the by-product light component from the gas phase product. In the reactor 5, in order to prevent the inner wall of the reactor 5 from affecting the reaction, 3g / h of dimethyl disulfide can be added for passivation of the metal. The dryer can specifically use adsorption fillers such as 5A molecular sieves to remove water in the gas phase product obtained by the gas-liquid separation unit 300 and hydrogen sulfide generated by the decomposition of dimethyl disulfide in the reactor 5, which can reduce the corrosion risk of the back-end equipment and prevent the subsequent cryogenic treatment device from freezing. The drying device 14 can use a drying device with corresponding functions well known in the art, for example, it can include multiple dryers, such as two dryers, etc., and the conventional operation in the art can be used to perform the drying operation and regeneration operation of the dryer, etc., and there is no special restriction on this. The cryogenic separation device 15 can adopt corresponding devices well known in the art, such as a cold box, etc., and there is no particular limitation on this. For example, the gas phase product is cooled from 40°C to -152°C by the cryogenic separation device 15, so that by-product light components such as hydrogen, methane, ethane and ethylene can be separated from C3, and the by-product methane, ethane and ethylene and part of the hydrogen are used as fuel for the feed heating furnace 1, and the liquid C3 product (mainly including propylene and unreacted propane, and may also contain a small amount of residual by-product C4 and above heavy components) enters the downstream separation unit to finally separate the propylene product. The cryogenic separation device 15 can recover the latent heat of vaporization of liquid propane and the coldness of the high-pressure gas expansion output from the gas-liquid separation unit 300.

[0068] The second aspect of the present invention further provides a process for carrying out a propane dehydrogenation reaction using the propane dehydrogenation reaction system described above. The specific description of the system can be found in the above text, and will not be repeated one by one. The process specifically comprises the following steps:

[0069] (1) feeding propane feed into a feed heating furnace 1, and heating the propane feed by providing heat through combustion of fuel in the feed heating furnace 1 to obtain heated propane feed and flue gas;

[0070] (2) sending the flue gas to the heat recovery unit 100 to perform heat exchange with the water phase obtained in the wastewater treatment unit 500 to obtain cooled flue gas and preheated water phase; performing gas-liquid separation on the cooled flue gas to obtain a first gas phase and a first liquid phase, wherein the first gas phase mainly includes carbon dioxide and a small amount of water;

[0071] (3) reacting the heated propane feed with the first gas phase in the presence of a catalyst in the reactor 5 of the reaction unit 200 to obtain a product stream comprising propylene, propane, hydrogen and carbon monoxide;

[0072] (4) sending the product stream and the first liquid phase to the gas-liquid separation unit 300 for treatment to obtain a gas phase product, and separating the oily wastewater containing heavy hydrocarbons (specifically, heavy hydrocarbons with carbon content of four or more produced as by-products) and water;

[0073] The gas phase product is sent to the gas phase product post-processing unit 400 for drying and deep cold separation to obtain a liquid phase C3 product and a by-product light component; the by-product light component is sent to the feed heating furnace 1 of step (1) to be burned as fuel;

[0074] (5) The oily wastewater is sent to the wastewater treatment unit 500 for treatment to obtain a water phase and an oil phase. Preferably, the oil content in the water phase is below 0.1 mg / L; the water phase is circulated to the heat recovery unit 100 of step (2) for heat exchange to generate steam later; and the oil phase is sent to the feed heating furnace 1 of step (1) for combustion as fuel.

[0075] In step (3), the heated propane feed is reacted with the first gas phase in the presence of a catalyst, wherein carbon deposits are reduced by oxidation and water gas reaction, so that the catalyst performance can be maintained at a high level for a long time, while the propane partial pressure is reduced, and the propane conversion rate can be increased, for example, by 3%, and carbon monoxide and hydrogen can be increased, for example, 13 t / h of carbon monoxide and 0.2 t / h of hydrogen.

[0076] In step (1), the propylene feed is heated to the desired target temperature by the feed heater 1, so as to meet the conditions for entering the reactor 5 and contacting with the catalyst for dehydrogenation reaction, for example, heating to about 590°C. Preferably, in step (1), the feed heater 1 adopts a forced ventilation oxygen-enriched combustion mode, and the feed heater 1 uses pure oxygen for combustion support, so as to minimize the energy waste caused by the use of air for combustion support, which results in part of the heat being used to heat the nitrogen therein, and reduce the generation of NOx. Specifically, the excess oxygen content in the feed heater 1 is maintained at about 3%, and the heat is recovered through the convection section of the heater for steam production, for example, 52t / h of S40 steam can be produced, and the steam can be used as a heat source for the separation unit; in some examples, the reaction raw material propane feed can be heated from 452°C to 590°C in the radiation section of the heater. In the present invention, the catalyst in the reactor can be a corresponding catalyst used in the art for propane dehydrogenation reaction, such as a non-precious metal supported catalyst well known in the art, wherein the non-precious metal is such as but not limited to Zn, Cr, etc., and can be a commercially available corresponding catalyst or a corresponding catalyst prepared according to a method known in the art, and there is no particular limitation on this.

[0077] Furthermore, the method further comprises the following steps: in step (2), the preheated water phase is fed into the convection section of the heating furnace for heat exchange with the flue gas, so that the preheated water phase is converted into steam.

[0078] Furthermore, the following steps are also included: in step (2), in the heat recovery unit 100, the flue gas flows through the non-phase change heat exchanger 2 and the phase change heat exchanger 3 in the heat recovery unit 100 successively, and then enters the gas-liquid separation device 4 for gas-liquid separation, thereby obtaining a first gas phase and a first liquid phase. Specifically, in the phase change heat exchanger 3, the flue gas is heat exchanged with the water phase obtained in the wastewater treatment unit 500 to obtain a preheated water phase; in the non-phase change heat exchanger 2, the flue gas is heat exchanged with the preheated water phase to obtain a preheated water phase, and the preheated water phase then enters the convection section of the feed heating furnace 1 to generate steam. In some examples, the temperature on the flue gas side of the non-phase change heat exchanger 2 is reduced from 352°C to 120°C, and the circulating water temperature is increased from 55°C to 145°C; the temperature on the flue gas side of the phase change heat exchanger 3 is reduced from 120°C to 65°C, and the circulating water temperature is increased from 25°C to 55°C. Then the flue gas enters the gas-liquid separation device 4.

[0079] Furthermore, the following steps are included: In step (1), the propane feed to be fed into the feed heating furnace 1 is pre-heated with the product stream output from the reactor 5 in the inlet and outlet material heat exchanger 6, so that the heat in the system is fully utilized. Preferably, the product stream after the heat exchange in the inlet and outlet material heat exchanger 6 is fed into the compressor feed cooler 7 for cooling, and then fed into the gas-liquid separation unit 300 for treatment.

[0080] Furthermore, the following steps are included: in step (5), the oily wastewater is first sent to the demulsifier 16 of the wastewater treatment unit 500 for demulsification, and then sent to the de-oiling coalescer 17 of the wastewater treatment unit 500 for oil-water separation to obtain a water phase and an oil phase; the water phase is then sent to the heat recovery unit 100 for heat exchange, and then enters the feed heating furnace 1 for further heating to generate steam; the oil phase is sent to the feed heating furnace 1 as fuel for combustion. Specifically, in the demulsifier 16, the water-in-oil structure of the oily wastewater can be destroyed by adding a demulsifier, and then enters the de-oiling coalescer 17 to continuously coalesce small oil droplets into large oil droplets and then remove the water layer, for example, to control the oil content in the water phase to less than 0.1 mg / L. The demulsifier can be a conventional corresponding reagent in the art, and there is no particular limitation on this. The separated water phase is preheated by the waste heat recovery unit 100 and enters the feed heating furnace 1 to generate steam. The separated oil phase enters the feed heating furnace 1 as fuel.

[0081] Compared with the prior art, the new propane dehydrogenation reaction process provided by the present invention is characterized in that the first gas phase containing carbon dioxide and a small amount of water obtained by heat recovery and gas-liquid separation of flue gas is sent to the reactor, and the oily wastewater obtained by gas-liquid separation of the first liquid phase and the reaction product is further treated by wastewater to obtain a water phase for heat exchange in the system to produce steam, and the by-product light components separated from the oil phase and the gas phase product are supplied to the feed heating furnace as fuel; it can reduce carbon dioxide and wastewater emissions, and is a new green and low-carbon reaction process; secondly, through partial oxidation of carbon dioxide and water-gas reaction of water, high-carbon coking materials produced by high-temperature cracking and olefin polymerization are converted into hydrogen and carbon monoxide, while improving the atomic utilization rate, the waste of energy and reaction time caused by catalyst regeneration can be avoided, and the present invention does not need to set up an additional regeneration air heating furnace for catalyst regeneration; the present invention can also effectively recover exhaust heat, further reducing the energy consumption and production cost of the device. The present invention utilizes the oxidation of carbon dioxide in flue gas and the water-gas reaction to reduce the carbon deposition of the catalyst, extend the reaction cycle, and increase production capacity. At the same time, the heat of the flue gas is fully utilized to heat the wastewater, reducing the overall reaction energy consumption.

[0082] The present invention is further described below by way of examples, but it should not be understood that the present invention is limited thereto.

[0083] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in the art can be used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be purchased commercially.

[0084] The catalyst used in the following Example 1 and Comparative Example 1 is the same, which is a commercially available catalyst Clariant Catofin 310 catalyst.

[0085] Example 1

[0086] This embodiment Figure 2 The propane dehydrogenation reaction is carried out in the propane dehydrogenation reaction system shown. For the specific description of the system, please refer to the previous description, which will not be repeated here.

[0087] The specific operation process is as follows:

[0088] 1) The propane feed first exchanges heat with the product flow output from the reactor 5 in the inlet and outlet material heat exchanger 6, and then enters the radiation section of the feed heating furnace 1. The heat generated by the combustion of the fuel in the feed heating furnace heats the propane feed from 452°C to 590°C, thereby obtaining heated propane feed and generating flue gas;

[0089] The fuel used in the feed heating furnace 1 is the by-product light components separated in the gas phase product post-processing unit 400 and the oil phase separated in the wastewater treatment unit 500; specifically, the by-product light components mainly include methane, ethane, ethylene and hydrogen, etc., with a specific composition of 35.8% hydrogen, 29.6% methane, 20.2% ethane, 1.0% propane, 1.0% butane, 0.3% nitrogen, 10.1% carbon monoxide, 2.0% carbon dioxide, molar percentage, and a flow rate of 4.05t / h; the composition of the oil phase is mainly C8-C20 aromatics, with a flow rate of about 22kg / h. The feed heating furnace 1 adopts a forced ventilation oxygen-enriched combustion mode, using pure oxygen to assist combustion. The flow rate of pure oxygen used is 13.4t / h. The excess oxygen content is maintained at 3%, and the flue gas composition is mainly 63.2% water, 3% oxygen, and 33.8% carbon dioxide, in molar percentage; the exhaust temperature of the flue gas after the heat is recovered by the convection section of the feed heating furnace 1 is 308°C. The convection section of the feed heating furnace 1 is used to produce steam. Specifically, the preheated water phase output by the heat recovery unit 100 is further heated by the flue gas flowing through the convection section and converted into steam, which can produce S40 steam 52t / h. Steam can be used as a heat source for downstream separation units.

[0090] 2) The flue gas discharged from the feed heating furnace 1 is sent to the heat recovery unit 100 through the flue gas discharge pipe 20 for waste heat recovery. In the heat recovery unit 100, the flue gas flows through the non-phase change heat exchanger 2 and the phase change heat exchanger 3 in sequence, and then enters the gas-liquid separation device 4 for gas-liquid separation; specifically, in the phase change heat exchanger 3, the flue gas is heat exchanged with the water phase (or called circulating water) obtained in the wastewater treatment unit 500 to obtain a preheated water phase; in the non-phase change heat exchanger 2, the flue gas is heat exchanged with the preheated water phase to obtain a preheated water phase. The non-phase change heat exchanger 2 is used to fully recover the heat of the flue gas while avoiding the dew point corrosion problem caused by water liquefaction, which can reduce the material grade of the heat exchanger and thus reduce investment. The phase change heat exchanger 3 is used to fully recover the phase change heat of water vapor in the flue gas, and at the same time, the water liquefaction process removes nitrogen and sulfur oxides in the flue gas to avoid subsequent corrosion to the reactor 5. The flue gas temperature of the non-phase change heat exchanger 2 is reduced from 308°C to 130°C, and the circulating water temperature is increased from 109°C to 127°C. The flue gas temperature of the phase change heat exchanger 3 is reduced from 130°C to 35°C, and the circulating water temperature is increased from 25°C to 109°C. After that, the flue gas enters the gas-liquid separation device 4, and the first gas phase and the first liquid phase are obtained by gas-liquid separation; the main components of the first gas phase are 5.5% water, 7.7% oxygen and 86.7% carbon dioxide, in molar percentage.

[0091] 3) The heated propane feed obtained in the feed heating furnace 1 and the first gas phase obtained in the gas-liquid separation device 4 of the heat recovery unit 100 are fed as reactor feed to the reactor 5 of the reaction unit 200. The composition of the heated propane feed and the first gas phase after mixing is mainly 0.9% ethane, 0.9% propylene, 94.0% propane, 0.6% butane, 0.2% water, 0.2% oxygen, 3.2% carbon dioxide, by mole percentage. The flow rate is 305t / h. Entering the reactor 5 for reaction, the inlet temperature of the reactor 5 is controlled to be 590°C and the pressure is -50kPa. The outlet temperature of the reactor 5 is 565°C, and the reaction products in the product flow are mainly composed of 32.6% hydrogen, 1.2% methane, 1.4% ethane, 0.2% ethylene, 32.9% propane, 25.4% propylene, 0.3% nitrogen, 5.3% carbon monoxide, 0.1% carbon dioxide, and 0.6% heavy hydrocarbons above C4, by mole percentage. After the product stream is produced, it exchanges heat with the propane feed in the inlet and outlet material heat exchanger 6 and enters the gas-liquid separation unit 300. The propane feed is heated from 25° C. to 452° C., and the temperature of the product stream is cooled from 565° C. to 142° C. At the same time, in order to prevent the inner wall of the reactor 5 from affecting the reaction, 3 kg / h of dimethyl disulfide is added to passivate the metal.

[0092] 4) The product stream after heat exchange in and out of the material heat exchanger 6 is sent to the compressor feed cooler 7 to cool to 40°C, and then enters the gas-liquid separation unit 300 with the first liquid phase obtained in the gas-liquid separation device 4 of the heat recovery unit 100 to separate heavy hydrocarbons and water. Specifically, Figure 2 As shown, in the primary gas-liquid separation tank 8, heavy hydrocarbons and water are separated from the gas phase product once and then enter the compressor 9. After the primary compression, the pressure of the gas phase product is increased from -50kPa to 0.6MPa; the gas phase product then enters the interstage cooler 10, and the temperature is reduced from 162°C to 40°C; the gas phase product then enters the secondary gas-liquid separation tank 11 for gas-liquid separation, and heavy hydrocarbons and water are further separated from the gas phase product. The gas phase product after gas-liquid separation enters the compressor 9 for secondary compression, and the pressure of the gas phase product is further increased to 1.2MPa, and then it is further cooled by the interstage cooler 10, and the temperature is reduced from 154°C to 40°C; then it enters the tertiary gas-liquid separation tank 13 to further separate heavy hydrocarbons and water. The heavy hydrocarbons and water separated in each gas-liquid separation tank will enter the wastewater treatment unit 500 as emulsified oily wastewater, and the total amount of oily wastewater is 5.2t / h. The gaseous product extracted from the tertiary gas-liquid separation tank 13 enters the gaseous product post-processing unit 400 .

[0093] In the gas phase product post-processing unit 400, the gas phase product obtained by the gas-liquid separation unit 300 is first sent to the drying device 14 for drying, and the water and hydrogen sulfide contents in the gas phase product after drying are respectively less than 1ppm; then it is sent to the deep cold separation device 15, and the gas phase product is cooled from 40°C to -152°C, so that the by-product hydrogen, methane and other C3 components can be separated. The by-product methane, ethane and ethylene and part of the hydrogen (i.e., the by-product light components) enter the gas phase stream, and the by-product light components are sent to the feed heating furnace 1 as the fuel of the heating furnace; the liquid phase C3 product (mainly 53.0% propane, 41.0% propylene, 0.1% hydrogen, 1.3% methane, 2.3% ethane, 0.3% ethylene, 0.8% carbon monoxide, 0.2% carbon dioxide, 1.0% C4 heavy hydrocarbons, etc., in molar percentage) enters the downstream separation unit to finally separate the propylene product.

[0094] 5) The oily wastewater obtained in the gas-liquid separation unit 300 is sent to the wastewater treatment unit 500 for treatment. Specifically, the oily wastewater is first sent to the demulsifier 16, and the water-in-oil structure of the oily wastewater is destroyed by adding a demulsifier (cationic organic demulsifier SM535, dosage 1000 mg / L), and then sent to the oil removal coalescer 17, and the oil content in the water phase is below 0.1 mg / L by continuously coalescing small oil droplets into large oil droplets and then removing them from the water layer. The separated water phase enters the heat recovery unit 100 in step 2) for heat exchange, and finally enters the convection section of the feed heating furnace 1 to produce steam. The separated oil phase enters the feed heating furnace 1 as fuel.

[0095] Comparative Example 1

[0096] This comparative example adopts Figure 3 , Figure 4 In the propane dehydrogenation reaction system shown in FIG. Figure 4 The system and the present invention shown Figure 2 The differences of the system shown mainly include: the need to add a regeneration unit 600, which is mainly used to remove the carbon deposits generated by the catalyst during the reaction and restore the catalyst activity to the initial level; no heat recovery unit and wastewater treatment unit are provided. The same catalyst is used in the reactor 5 of this comparative example and Example 1.

[0097] The specific operation process is as follows:

[0098] 1) The propane feed first exchanges heat with the product flow output from the reactor 5 in the inlet and outlet material heat exchanger 6, and then enters the radiation section of the feed heating furnace 1. The heat generated by the combustion of the fuel in the feed heating furnace heats the propane feed from 452°C to 590°C, thereby obtaining heated propane feed and generating flue gas;

[0099] The fuel used in the feed heating furnace is the by-product light component, and the specific composition is mainly 35.8% hydrogen, 29.6% methane, 20.2% ethane, 1.0% propane, 1.0% butane, 0.3% nitrogen, 10.1% carbon monoxide, 2.0% carbon dioxide, molar percentage, and the flow rate is 4.05t / h. The feed heating furnace 1 uses the natural ventilation mode, and the air flow rate is 57.6t / h. Maintaining the excess oxygen content at 3%, the flue gas composition is mainly 18.4% water, 0.6% oxygen, 10% carbon dioxide, and 71.0% nitrogen, molar percentage. The exhaust gas temperature after the flue gas recovers heat through the convection section is 308℃. The convection section of the feed heating furnace 1 is used to produce steam, which can produce 47t / h of S40 steam, and the steam is used as the heat source of the downstream separation unit. The radiation section of the feed heating furnace 1 is used to heat the reaction raw materials from 452℃ to 590℃. The exhaust heat of the feed heating furnace 1 is recovered by a non-phase-change heat exchanger 2 to preheat the air to 300° C., and the exhaust temperature is reduced to 130° C. The air enters the feed heating furnace 1 after being preheated by the non-phase-change heat exchanger 2 .

[0100] 2) Reactor 5 feed is propane raw material heated by feed heating furnace 1. The raw material composition is ethane 0.9%, propylene 0.6%, propane 97.6%, butane 0.9%, by mole percentage. The flow rate is 294t / h. Reacting in reactor 5, the inlet temperature of reactor 5 is controlled to be 590℃ and the pressure is -50kPa. The outlet temperature of reactor 5 is 565℃, and the main composition of the reaction products in the product flow is hydrogen 31.5%, methane 1.3%, ethane 1.5%, ethylene 0.2%, propane 36.3%, propylene 27.1%, nitrogen 0.3%, carbon monoxide 1.0%, carbon dioxide 0.1%, and carbon four or more heavy hydrocarbons 0.7%, by mole percentage. After the product stream is extracted and exchanges heat with the propane feed in the inlet and outlet material heat exchanger 6, the propane feed is heated from 25°C to 452°C, and the temperature of the product stream is cooled from 565°C to 142°C; then the product stream first flows through the compressor feed cooler 7 to cool to 40°C, and then enters the gas-liquid separation unit 300. At the same time, in order to prevent the inner wall of the reactor 5 from affecting the reaction, 3kg / h of dimethyl disulfide is added to passivate the metal.

[0101] 3) The process of treating the product stream in the gas-liquid separation unit 300 is the same as that in Example 1, and will not be described in detail. The difference is that in Comparative Example 1, the oily wastewater separated in the gas-liquid separation unit is directly discharged for treatment.

[0102] The process of sending the gas phase product treated by the gas-liquid separation unit 300 to the drying device 14 and the cryogenic separation device 15 of the gas phase product post-treatment unit 400 for treatment is the same as that in Example 1 and will not be repeated herein.

[0103] 4) In the reactor 5 of step 2), the catalyst is used for about nine minutes and then regenerated, and the regeneration time is about nine minutes. Specifically, the regeneration of the catalyst is carried out in the regeneration unit 600, and the carbon deposits are removed by reacting air with the carbon deposits on the catalyst. The regeneration unit 600 specifically includes a regeneration air heating furnace 18 and a regeneration reactor 19. Specifically, the hot air required for the regeneration reactor 19 is heated to 610°C by the regeneration air heating furnace 18. The fuel gas used by the regeneration air heating furnace 18 mainly consists of 23.8% hydrogen, 53.2% methane, 13.4% ethane, 0.7% propane, 0.7% butane, 0.2% nitrogen, 6.7% carbon monoxide and 1.3% carbon dioxide, in molar percentage, with a flow rate of 6.05t / h. The regeneration air heating furnace 18 uses a natural ventilation mode. The flow rate of air used is 57.6t / h. The excess oxygen content is maintained at 3%. The flue gas of the regeneration air heating furnace 18 is mainly composed of 18.4% water, 0.6% oxygen, 10% carbon dioxide and 71% nitrogen, in molar percentage. The exhaust gas of the regeneration air heating furnace 18 is mixed with the exhaust gas of the feed heating furnace 1 and then discharged to the atmosphere. The air heated by the regeneration air heating furnace enters the regeneration reactor 20 to undergo an oxidation reaction with the catalyst carbon deposits, removes the carbon deposits, and obtains a regenerated catalyst.

[0104] From the perspective of emission reduction, Example 1 can basically achieve zero carbon dioxide emissions, and all carbon is converted into carbon monoxide products for external delivery. However, Comparative Example 1 needs to discharge 24.9 t / h of carbon dioxide. At the same time, it needs to discharge 5.2 t / h of oily wastewater. Based on the downstream treatment fee of 30 yuan per ton of wastewater, the annual wastewater treatment cost is 1.2 million yuan.

[0105] From the perspective of energy saving, in Example 1, the phase change heat exchanger 3 of the heat recovery unit 100 can recover an additional 7.9MW of flue gas heat, and the heavy hydrocarbons recovered by the wastewater treatment unit can replace 0.02t / h of fuel gas with the same calorific value. Since the reaction process does not require an additional regeneration unit 600 for catalyst regeneration, the heating energy consumption of the regeneration air can be saved, that is, about 6t / h of fuel gas.

[0106] From the perspective of reaction, in Example 1, the first gas phase containing carbon dioxide and water is added to the feed of reactor 5, and the carbon deposition is reduced by oxidation and water gas reaction, so that the catalyst performance can be maintained at a high level for a long time, while reducing the propane partial pressure, the propane conversion rate can be increased by 3%, and 13t / h of carbon monoxide and 0.2t / h of hydrogen can be increased. The catalyst in the above Example 1 can run stably for four years; the catalyst in Comparative Example 1 needs to be regenerated frequently, and each regeneration will cause a certain degree of attenuation of the catalyst activity. The overall life of the catalyst in Comparative Example 1 is reduced to three years, and the regeneration process requires a lot of time and heat.

[0107] It is easy to understand that the above embodiments are only examples for clear explanation and do not mean that the present invention is limited thereto. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the present invention.

Claims

1. A propane dehydrogenation reaction system, characterized in that: The system includes a feed heating furnace, a heat recovery unit, a reaction unit, a gas-liquid separation unit, a wastewater treatment unit, and a gas phase product post-treatment unit; The feed heating furnace is used to heat the propane feed by burning fuel and obtain heated propane feed and flue gas; The heat recovery unit is used to perform heat exchange between the flue gas and the water phase obtained in the wastewater treatment unit to obtain cooled flue gas and a preheated water phase, and to perform gas-liquid separation on the cooled flue gas to obtain a first gas phase and a first liquid phase; The reaction unit comprises a reactor for reacting the heated propane feed and the first gas phase in the presence of a catalyst to obtain a product stream comprising propylene, propane, hydrogen and carbon monoxide; The gas-liquid separation unit is used to process the product stream and the first liquid phase to obtain a gas phase product and oily wastewater containing heavy hydrocarbons and water; The wastewater treatment unit is used to treat the oily wastewater to obtain a water phase and an oil phase; The gas phase product post-processing unit is used to dry and cryogenically separate the gas phase product to obtain a liquid phase C3 product and a by-product light component; The gas phase product post-processing unit and the wastewater treatment unit are respectively connected to the feed heating furnace to feed the by-product light components and the oil phase into the feed heating furnace for use as the fuel.

2. The propane dehydrogenation reaction system according to claim 1, characterized in that: The heat recovery unit is connected to the convection section of the feed heating furnace so that the preheated water phase exchanges heat with the flue gas flowing through the convection section to obtain steam.

3. The propane dehydrogenation reaction system according to claim 1 or 2, characterized in that: The smoke outlet of the feed heating furnace is connected to the smoke exhaust pipe; The heat recovery unit comprises a non-phase-change heat exchanger, a phase-change heat exchanger and a gas-liquid separation device; and along the flow direction of the flue gas in the flue gas exhaust pipe, the non-phase-change heat exchanger, the phase-change heat exchanger and the gas-liquid separation device are connected in series in sequence through the flue gas exhaust pipe; The wastewater treatment unit is connected to a water phase delivery pipe for outputting the water phase, and the water phase delivery pipe is connected to the phase change heat exchanger, so that the water phase exchanges heat with the flue gas flowing through the phase change heat exchanger, and obtains a preliminarily preheated water phase; The non-phase-change heat exchanger is also connected to the water phase outlet of the phase-change heat exchanger through a preliminary preheated water phase output pipeline, so that the preliminary preheated water phase exchanges heat with the flue gas flowing through the non-phase-change heat exchanger to obtain the preheated water phase; The gas-liquid separation device is used to perform gas-liquid separation on the flue gas output by the phase change heat exchanger to obtain the first gas phase and the first liquid phase.

4. The propane dehydrogenation reaction system according to any one of claims 1 to 3, characterized in that: The reaction unit further comprises an inlet and outlet material heat exchanger for exchanging heat between the product stream before entering the gas-liquid separation unit and the propane feed before entering the feed heating furnace; Preferably, the reaction unit further comprises a compressor feed cooler, which is arranged between the inlet and outlet material heat exchanger and the gas-liquid separation unit and is used to cool the product flow output by the inlet and outlet material heat exchanger before entering the gas-liquid separation unit.

5. The propane dehydrogenation reaction system according to any one of claims 1 to 4, characterized in that: The gas-liquid separation unit includes a multi-stage gas-liquid separation tank connected in series, and between two adjacent gas-liquid separation tanks, a compressor and an interstage cooler are sequentially connected in series between the gas phase outlet of the upstream gas-liquid separation tank and the feed inlet of the downstream gas-liquid separation tank.

6. The propane dehydrogenation reaction system according to any one of claims 1 to 5, characterized in that: The wastewater treatment unit includes an emulsifier and an oil removal coalescer; The demulsifier is used to destroy the oil-in-water structure of the oily wastewater; The oil removal coalescer is used to process the material after being processed by the demulsifier, and separate the water phase and the oil phase.

7. The propane dehydrogenation reaction system according to any one of claims 1 to 6, characterized in that: The gas phase product post-processing unit includes a drying device and a cryogenic separation device; The drying device is used to dry the gas phase product to remove water and hydrogen sulfide entrained in the gas phase product; The cryogenic separation device is used to perform the cryogenic separation on the gas phase product after being processed by the drying device to obtain a liquid phase C3 product and the by-product light components.

8. A process for carrying out propane dehydrogenation reaction using the propane dehydrogenation reaction system according to any one of claims 1 to 7, characterized in that: The steps include: (1) feeding propane feed into the feed heating furnace, and heating the propane feed by providing heat through combustion of fuel in the feed heating furnace to obtain heated propane feed and flue gas; preferably, the feed heating furnace uses pure oxygen for combustion support; (2) sending the flue gas to a heat recovery unit to perform heat exchange with the water phase obtained in the wastewater treatment unit to obtain cooled flue gas and a preheated water phase; performing gas-liquid separation on the cooled flue gas to obtain a first gas phase and a first liquid phase; (3) reacting the heated propane feed with the first gas phase in the reactor of the reaction unit in the presence of a catalyst to obtain a product stream comprising propylene, propane, hydrogen and carbon monoxide; (4) sending the product stream and the first liquid phase into the gas-liquid separation unit for treatment to obtain a gas phase product and separate the oily wastewater containing heavy hydrocarbons and water; The gas phase product is sent to the gas phase product post-processing unit for drying and deep cold separation to obtain a liquid phase C3 product and a by-product light component; the by-product light component is sent to the feed heating furnace of step (1) to be burned as fuel; (5) The oily wastewater is sent to the wastewater treatment unit for treatment to obtain a water phase and an oil phase; the water phase is circulated to the heat recovery unit of step (2) for heat exchange; and the oil phase is sent to the feed heating furnace of step (1) for combustion as fuel.

9. The process according to claim 8, characterized in that The following steps are also included: In step (2), the preheated water phase is sent to the convection section of the feed heating furnace to exchange heat with the flue gas, so that the preheated water phase is converted into steam; And / or, in step (2), in the heat recovery unit, the flue gas is passed through a non-phase change heat exchanger and a phase change heat exchanger in sequence, and then enters a gas-liquid separation device for gas-liquid separation to obtain the first gas phase and the first liquid phase; in the phase change heat exchanger, the flue gas is heat exchanged with the water phase obtained in the wastewater treatment unit to obtain a preliminarily preheated water phase; in the non-phase change heat exchanger, the flue gas is heat exchanged with the preliminarily preheated water phase to obtain the preheated water phase.

10. The process according to claim 8, characterized in that The following steps are also included: In step (1), the propane feed to be fed into the feed heating furnace is preliminarily heat exchanged with the product stream output from the reactor in an inlet and outlet material heat exchanger; preferably, the product stream after heat exchange in the inlet and outlet material heat exchanger is fed into a compressor feed cooler for cooling, and then fed into the gas-liquid separation unit; And / or, in step (5), the oily wastewater is first sent to the demulsifier of the wastewater treatment unit for demulsification, and then sent to the oil removal coalescer of the wastewater treatment unit for oil-water separation to obtain the water phase and the oil phase.

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