Alkane dehydrogenation reaction and catalyst regeneration system and alkane dehydrogenation reaction and catalyst regeneration method

Abstract

The invention relates to the field of alkane dehydrogenation reaction, and discloses an alkane dehydrogenation reaction and catalyst regeneration system and an alkane dehydrogenation reaction and catalyst regeneration method, the system comprises a heat supply system, a reaction system and a regeneration system; the reaction system comprises a feeding and discharging heat exchanger and a dehydrogenation isothermal tubular reactor; the dehydrogenation isothermal tubular reactor is used for carrying out an alkane dehydrogenation reaction; the feeding and discharging heat exchanger is used for carrying out heat exchange on alkane feeding and product gas at an outlet of the dehydrogenation isothermal tubular reactor; the heat supply system is used for supplying heat to the shell side of the dehydrogenation isothermal tubular reactor through an inert heat-conducting fluid; the regeneration system comprises a regeneration isothermal tubular reactor and an air feeding and discharging heat exchanger; the regeneration isothermal tubular reactor is used for regenerating the catalyst; and the air feeding and discharging heat exchanger is used for carrying out heat exchange on compressed air and regenerated flue gas at the outlet of the regenerated isothermal tubular reactor. The system can improve the alkane conversion rate and olefin selectivity, and reduce the thermal load of the feed heater.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of alkane dehydrogenation reaction, and in particular to an alkane dehydrogenation reaction and catalyst regeneration system, an alkane dehydrogenation reaction and catalyst regeneration method. BACKGROUND

[0002] In the existing propane dehydrogenation device process with high market share, mainly including fixed bed propane dehydrogenation device and moving bed propane dehydrogenation device two kinds of process technology. In the process of propane dehydrogenation reaction, the higher the reaction temperature, the higher the main reaction conversion rate and the reaction rate, but the higher the reaction temperature, the more the phenomenon of carbon deposition and catalyst coking, so it is meaningful to control the reaction temperature in the propane dehydrogenation reactor within the best operating range. At the same time, propane dehydrogenation reaction is an endothermic reaction, which needs to consume a lot of heat in the reaction process. Therefore, in the existing propane dehydrogenation device, different process design methods are used to meet the demand of propane dehydrogenation reaction.

[0003] In the fixed bed propane dehydrogenation process, the reaction system adopts multiple adiabatic horizontal fixed bed propane dehydrogenation reactors in parallel process, and there are problems such as low reaction gas temperature at the outlet of the reactor, large temperature difference between the inlet and outlet of the reactor, etc. in the reaction process, thereby reducing the reaction rate and conversion rate of propane dehydrogenation. In order to further adjust the bed temperature distribution in the propane dehydrogenation reactor, it is usually necessary to additionally add heat generating materials to provide heat for the reaction process, which increases the investment and operating cost of the reaction system. In the moving bed propane dehydrogenation process, the reaction system adopts multiple adiabatic moving bed reactors in series process, in order to ensure that the propane dehydrogenation process is within a reasonable operating temperature range, a feed heating furnace is added between each reactor, which has problems such as large temperature difference between the inlet and outlet of the reaction, uneven temperature distribution in the reactor, low reaction conversion rate, etc. At the same time, in the existing propane dehydrogenation process device, in order to ensure the propane conversion rate and propylene selectivity, the reaction feed and the reactor itself need to be heated to a high temperature, and a heating furnace is needed to preheat the raw material. With the increase of the reaction feed temperature, the load of the heating furnace in the reaction system is further increased, and the energy consumption of the entire propane dehydrogenation device is increased.

[0004] In the existing alkane dehydrogenation process, the temperature difference between the inlet and outlet of the reaction is large, and the catalytic activity of the catalyst is limited by the reaction temperature, which leads to low reaction conversion rate and low olefin selectivity. Therefore, a reaction system capable of improving the catalytic activity and product selectivity of alkane dehydrogenation reaction is needed. SUMMARY

[0005] The present application aims to overcome the problems of large temperature difference between the inlet and outlet of the reactor, short residence time at the optimal reaction temperature in the reactor, low reaction conversion rate, low olefin selectivity, easy carbon deposition and reactor coking in the prior art, and provide an alkane dehydrogenation reaction and catalyst regeneration system and method, which can improve the energy utilization efficiency of the alkane dehydrogenation reaction, maintain the alkane dehydrogenation reaction at the optimal reaction temperature, improve the alkane conversion rate and the olefin selectivity, and reduce the heat load of the feed heater.

[0006] To achieve the above-mentioned purpose, the present application provides an alkane dehydrogenation reaction and catalyst regeneration system in the first aspect, wherein the system comprises a heating system, a reaction system and a regeneration system.

[0007] The reaction system comprises an inlet and outlet heat exchanger and a dehydrogenation isothermal tubular reactor.

[0008] The dehydrogenation isothermal tubular reactor is used for alkane dehydrogenation reaction.

[0009] The inlet and outlet heat exchanger is used for heat exchange between the alkane feed and the product gas at the outlet of the dehydrogenation isothermal tubular reactor.

[0010] The heating system is used to provide heat to the shell side of the dehydrogenation isothermal tubular reactor through the inert heat-conducting fluid.

[0011] The regeneration system comprises a regeneration isothermal tubular reactor and an air inlet and outlet heat exchanger.

[0012] The regeneration isothermal tubular reactor is used for catalyst regeneration.

[0013] The air inlet and outlet heat exchanger is used for heat exchange between the compressed air and the regeneration flue gas at the outlet of the regeneration isothermal tubular reactor.

[0014] Preferably, the system further comprises a steam generator for removing heat from the inert heat-conducting fluid at the outlet of the dehydrogenation isothermal tubular reactor and the regeneration isothermal tubular reactor.

[0015] The present application provides an alkane dehydrogenation reaction and catalyst regeneration method in the second aspect, wherein the method is carried out in the system of the first aspect, and the method comprises the following steps:

[0016] The inert heat-conducting fluid of the heating system provides heat to the reaction system and the regeneration system respectively, the alkane raw material of the reaction system is subjected to alkane dehydrogenation reaction to obtain product gas, and the dehydrogenation catalyst of the regeneration system after alkane dehydrogenation reaction is subjected to dehydrogenation catalyst regeneration.

[0017] The method further includes exchanging heat between the product gas from the dehydrogenation isothermal tubular reactor in the reaction system and the alkane feedstock, and exchanging heat between the compressed air in the regeneration system and the regeneration flue gas from the regeneration isothermal tubular reactor.

[0018] The beneficial effects achieved through the above technical solution are as follows:

[0019] (1) In this invention, the system improves the energy utilization efficiency of the alkane dehydrogenation reaction by carrying out the alkane dehydrogenation reaction in the reaction system, providing heat to the reaction system by the heating system, and regenerating the dehydrogenation catalyst by the regeneration system, thereby maintaining the alkane dehydrogenation reaction at the optimal reaction temperature, improving the alkane conversion rate and olefin selectivity, and reducing the heat load of the feed heater.

[0020] (2) In this invention, preferably, the shell side of the dehydrogenation isothermal tubular reactor provides heat for the alkane dehydrogenation reaction, avoiding the possibility of air leakage into the reactor and ensuring the safe operation of the reaction; at the same time, the heat supply to the reaction system and the regeneration system is flexibly adjusted by the steam generator, which reduces the burden on the circulating heater and avoids the overheating phenomenon of the heat supply system, thus avoiding safety hazards. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the alkane dehydrogenation reaction and catalyst regeneration system in Example 1;

[0022] Figure 2 This is a schematic diagram of the system for alkane dehydrogenation reaction and catalyst regeneration in Example 2.

[0023] Explanation of reference numerals in the attached figures

[0024] Figure 1

[0025] 1-Infeed / Discharge heat exchanger; 2-Infeed heater; 3A-Dehydrogenation isothermal tube reactor

[0026] Applicator

[0027] 3B - Regenerative isothermal tubular compressor; 4 - Circulating gas compressor; 5 - Circulating heater.

[0028] Applicator

[0029] 6-Air compressor 7-Air inlet / outlet heat exchanger 8-Regenerated flue gas cooler 9-Chimney 10-Air heater 11-Steam generator

[0030] Figure 2

[0031] 1-Infeed / Discharge heat exchanger; 2-Infeed heater; 3A, 3B-Dehydrogenation isothermal tube type.

[0032] reactor

[0033] 3C, 3D - Regeneration isothermal shell-and-tube 4-cycle air compressor 5-cycle heater

[0034] reactor

[0035] 6 - Air compressor 7 - Air charge and discharge heat exchanger 8 - Regeneration flue gas cooler 9 - Chimney 10 - Air heater 11 - Steam generator DETAILED DESCRIPTION

[0036] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not critical to the invention. Any numerical value, however, can include any values up to the stated value, or down to the stated value, in increments of one unit. For ranges, the endpoints are included in the ranges. The disclosure of a single value of a parameter or characteristic can be taken as disclosure of a range ending with the single value, unless the context clearly dictates otherwise. Multiple ranges and / or parameters or characteristics can be disclosed herein as disclosable alternatives.

[0037] The first aspect of the present application provides a system for alkane dehydrogenation reaction and catalyst regeneration, wherein the system comprises a heating system, a reaction system and a regeneration system;

[0038] The reaction system comprises an air charge and discharge heat exchanger and a dehydrogenation isothermal shell-and-tube reactor.

[0039] The dehydrogenation isothermal shell-and-tube reactor is used for alkane dehydrogenation reaction.

[0040] The air charge and discharge heat exchanger is used for heat exchange between alkane feed and product gas from the outlet of the dehydrogenation isothermal shell-and-tube reactor.

[0041] The heating system is used for providing heat to the shell side of the dehydrogenation isothermal shell-and-tube reactor by inert heat-conducting fluid.

[0042] The regeneration system comprises a regeneration isothermal shell-and-tube reactor and an air charge and discharge heat exchanger.

[0043] The regeneration isothermal shell-and-tube reactor is used for catalyst regeneration.

[0044] The air charge and discharge heat exchanger is used for heat exchange between compressed air and regeneration flue gas from the outlet of the regeneration isothermal shell-and-tube reactor.

[0045] In the present application, the system comprises a heating system, a reaction system and a regeneration system, the alkane dehydrogenation reaction is carried out in the reaction system, the heating system provides heat to the reaction system, and the regeneration system is used for dehydrogenation catalyst regeneration, thereby improving the energy utilization efficiency of the alkane dehydrogenation reaction, maintaining the alkane dehydrogenation reaction at the optimal reaction temperature, improving the alkane conversion rate and the olefin selectivity, and reducing the heat load of the feed heater.

[0046] According to the application, the inert heat-conducting fluid refers to a gas and / or liquid with stable properties capable of providing heat for the isothermal shell-and-tube reactor, preferably an inert heat-conducting gas, and more preferably circulating nitrogen.

[0047] In the application, the reaction system refers to a system in which the alkane feed is heated by the feed-and-discharge heat exchanger, enters the isothermal shell-and-tube reactor for alkane dehydrogenation reaction, and the product gas is sent to the downstream separation device after being heated by the feed-and-discharge heat exchanger.

[0048] According to the application, preferably, the reaction system comprises at least one dehydrogenation isothermal shell-and-tube reactor, preferably 2-10 dehydrogenation isothermal shell-and-tube reactors.

[0049] In the application, the dehydrogenation isothermal shell-and-tube reactor comprises a shell side and a tube side, the alkane feed enters the tube side from the top of the dehydrogenation isothermal shell-and-tube reactor in the reaction stage, passes through the catalyst bed in the shell-and-tube reactor, and the product gas after reaction is discharged from the bottom to the feed-and-discharge heat exchanger. Preferably, the isothermal shell-and-tube reactor is used for alkane dehydrogenation reaction, a heating system is arranged on the shell side of the isothermal shell-and-tube reactor, and the heating system is heated by the inert heat-conducting fluid. Compared with the conventional reactor, the temperature drop during the dehydrogenation reaction needs to increase the temperature of the feed, the isothermal shell-and-tube reactor can maintain the alkane dehydrogenation reaction at the optimum reaction temperature, reduce the temperature of the alkane feed at the inlet of the reactor, and reduce the heat load while improving the alkane conversion rate and the olefin selectivity.

[0050] In the application, when two or more dehydrogenation isothermal shell-and-tube reactors are connected, the dehydrogenation isothermal shell-and-tube reactors are connected in parallel.

[0051] According to the application, preferably, the reaction system further comprises a feed heater, the inlet of the feed heater is connected with the outlet of the feed-and-discharge heat exchanger, and the outlet of the feed heater is connected with the tube side of the dehydrogenation isothermal shell-and-tube reactor. In the application, the feed heater is used for heating the alkane feed after being heated by the feed-and-discharge heat exchanger, so that the alkane feed reaches the required temperature for the dehydrogenation reaction. The product gas at the outlet of the dehydrogenation isothermal shell-and-tube reactor is heated by the feed-and-discharge heat exchanger, the heat of the product gas is recovered and used for the reaction system, and the burden of the heating system is reduced.

[0052] In the application, the type of the feed-and-discharge heat exchanger is not particularly limited, and those skilled in the art can select conventional heat exchangers, preferably at least one selected from a pipe-coil heat exchanger, a plate heat exchanger, and a high-efficiency heat exchanger.

[0053] According to the application, preferably, the heating system is used for providing heat for the alkane dehydrogenation reaction. The heating system comprises a circulating gas compressor, which is used for compressing the inert heat-conducting fluid to provide heat for the shell side of the dehydrogenation isothermal shell-and-tube reactor.

[0054] According to the present application, preferably, the heat supply system further comprises a circulation heater, an inlet of the circulation heater is connected with an outlet of the circulation gas compressor, and an outlet of the circulation heater is connected with a shell side of the dehydrogenation isothermal tube reactor, for heating the inert heat-conducting fluid compressed by the circulation gas compressor. The type of the circulation heater is not particularly limited, and any type of the circulation heater capable of achieving the effect of heating the inert heat-conducting fluid can be used, and preferably at least one selected from an electric heater, a gas heater and an electric heating furnace.

[0055] According to the present application, preferably, the regeneration system further comprises an air compressor, for pressurizing air to obtain compressed air.

[0056] In the present application, the inert heat-conducting fluid is compressed by the circulation gas compressor to provide circulation power for the heat supply system, so as to ensure that the inert heat-conducting fluid can be recycled. When the temperature of the inert heat-conducting fluid is not high enough to meet the heat exchange requirement of the dehydrogenation isothermal tube reactor, the circulation heater is used to heat the compressed inert heat-conducting fluid to increase the temperature, and the inert heat-conducting fluid is sent to the shell side of the dehydrogenation isothermal tube reactor to provide heat for the dehydrogenation reaction of the alkanes, so as to ensure the normal heat exchange of the dehydrogenation isothermal tube reactor. When the temperature of the inert heat-conducting fluid meets the requirement, the circulation heater can be bypassed, and the compressed inert heat-conducting fluid from the circulation gas compressor is directly sent to the shell side of the dehydrogenation isothermal tube reactor.

[0057] In the present application, preferably, the heat supply system is independently operated, and the temperature of the inert heat-conducting fluid is controlled by the circulation heater bypass flow adjustment and the steam generator. The independent heat supply system effectively avoids air leakage to the reactor, and ensures the safety of the entire system.

[0058] In the present application, the regeneration system refers to a system for the regeneration of dehydrogenation catalysts, in which air is pressurized by an air compressor, heated by an air inlet and outlet heat exchanger, and then enters a regeneration isothermal tube reactor, and after the regeneration of the catalysts in the tube reactor, the regenerated flue gas is heated by the air inlet and outlet heat exchanger. Through the regeneration system, the regeneration of the dehydrogenation catalysts is realized, and the continuous long-period operation of the alkanes dehydrogenation reaction and the catalyst regeneration system is realized.

[0059] According to the present application, preferably, the regeneration system further comprises an air heater, an outlet of the air heater is connected with an inlet of the tube side of the regeneration isothermal tube reactor, for heating the outlet material of the air inlet and outlet heat exchanger. In the present application, the air heater is used to heat the air after heat exchange, so that the temperature of the air meets the temperature requirement for the regeneration of the dehydrogenation catalysts.

[0060] According to the present application, preferably, the regeneration system comprises at least one regeneration isothermal shell-and-tube reactor, preferably 2-10 regeneration isothermal shell-and-tube reactors. In the present application, when two or more regeneration isothermal shell-and-tube reactors are connected, the regeneration isothermal shell-and-tube reactors are connected in parallel.

[0061] In the present application, the number of the dehydrogenation isothermal shell-and-tube reactors and the regeneration isothermal shell-and-tube reactors can be adjusted according to the production capacity of the device, and the isothermal shell-and-tube reactors can be reasonably controlled in the reaction stage or the regeneration stage, so that the production capacity of the device is controllable. Preferably, the number of the dehydrogenation isothermal shell-and-tube reactors and the regeneration isothermal shell-and-tube reactors is the same.

[0062] In the present application, preferably, the dehydrogenation isothermal shell-and-tube reactors and the regeneration isothermal shell-and-tube reactors are connected in parallel, and the dehydrogenation reaction of alkanes is carried out in the dehydrogenation isothermal shell-and-tube reactors at the same time as the regeneration of the dehydrogenation catalyst is carried out in the regeneration isothermal shell-and-tube reactors, and the dehydrogenation reaction of alkanes is continuously carried out by switching.

[0063] According to the present application, preferably, the regeneration system further comprises a regeneration flue gas cooler connected to the outlet of the air inlet and outlet heat exchanger for cooling the regenerated flue gas after heat exchange. In the present application, the regeneration flue gas cooler further cools the regenerated flue gas after heat exchange to meet the emission standards.

[0064] In the present application, preferably, the regeneration system further comprises a chimney connected to the outlet of the regeneration gas cooler for discharging the cooled flue gas.

[0065] According to the present application, preferably, the system further comprises a steam generator for removing heat from the inert heat-conducting fluid at the outlet of the dehydrogenation isothermal shell-and-tube reactor and the regeneration isothermal shell-and-tube reactor. In the present application, the steam generator is used to remove heat from the inert heat-conducting fluid and produce steam as a byproduct, which avoids the overheating phenomenon caused by heat accumulation in the heating system, has high energy utilization efficiency, low energy consumption, and high economic benefits.

[0066] In the present application, preferably, the system further comprises a shunt pipe and a converging pipe. The shunt pipe is used to shunt the inert heat-conducting fluid in the heating system, and after shunting, part of the inert heat-conducting fluid enters the reaction system to provide heat for the dehydrogenation reaction of alkanes, and part of the inert heat-conducting fluid enters the regeneration system to heat the bed of the dehydrogenation catalyst after cooling to the initial reaction temperature range. The converging pipe is used to converge the inert heat-conducting fluid at the outlet of the dehydrogenation isothermal shell-and-tube reactor and the regeneration isothermal shell-and-tube reactor, and the converged inert heat-conducting fluid enters the steam generator for heat removal.

[0067] The second aspect of the present application provides a method for alkane dehydrogenation reaction and catalyst regeneration, wherein the method is carried out in the system of the first aspect, and the method comprises the following steps:

[0068] The inert heat-conducting fluid of the heat supply system provides heat to the reaction system and the regeneration system respectively, the alkane raw material of the reaction system is subjected to alkane dehydrogenation reaction to obtain product gas, and the dehydrogenation catalyst of the regeneration system after alkane dehydrogenation reaction is subjected to dehydrogenation catalyst regeneration.

[0069] In the method, the product gas at the outlet of the dehydrogenation isothermal shell-and-tube reactor in the reaction system is subjected to heat exchange with the alkane raw material, and the compressed air in the regeneration system is subjected to heat exchange with the regeneration flue gas at the outlet of the regeneration isothermal shell-and-tube reactor.

[0070] In the present application, preferably, the alkane dehydrogenation reaction and catalyst regeneration are carried out in the system of the first aspect by using the above method, the heat supply system is used to ensure that the alkane dehydrogenation reaction is carried out at an optimal temperature, the phenomenon of carbon deposition and catalyst coking is reduced, the reaction temperature is controllable, the conversion rate of alkane in the reaction is high, the selectivity of olefin is high, the energy utilization efficiency is improved, and the safety of the reaction system is ensured.

[0071] In the present application, preferably, the temperature change of the alkane dehydrogenation reaction and catalyst regeneration process is not more than 50 DEG C. The temperature difference of the entire process of the alkane dehydrogenation reaction and catalyst regeneration is small, the isothermal shell-and-tube reactor is used to ensure that the alkane dehydrogenation reaction and catalyst regeneration are carried out in an optimal temperature range, the temperature at the inlet of the reactor is not too high, the phenomenon of dehydrogenation catalyst carbon deposition and deactivation due to the limitation of high reaction temperature is reduced, and the range of dehydrogenation catalyst suitable for the conditions of the alkane dehydrogenation reaction is wider.

[0072] According to the present application, preferably, the alkane dehydrogenation reaction is carried out in the presence of dehydrogenation catalyst. The type and source of the dehydrogenation catalyst are not particularly limited, and the dehydrogenation catalyst can be commercially available or prepared by using an existing method. A person skilled in the art can select a conventional alkane dehydrogenation catalyst, and preferably, the catalyst is a Cr-based catalyst.

[0073] In the present application, the volume space velocity of the alkane raw material and the catalyst is not particularly limited, and a person skilled in the art can adjust the volume space velocity according to the alkane dehydrogenation reaction condition and the adaptability of the selected catalyst.

[0074] According to the present application, preferably, the conditions of the alkane dehydrogenation reaction comprise that the operating temperature is 550-610 DEG C, and preferably, the operating temperature is 570-590 DEG C; and the operating pressure is -0.05 to 0.5 MPaG, and preferably, the operating pressure is -0.05 to 0.05 MPaG.

[0075] According to the present invention, preferably, the alkane feedstock is a low-carbon alkane. The low-carbon alkane, as commonly understood in the art, refers to a C2-C4 alkane feedstock, preferably propane and / or butane.

[0076] According to the present invention, preferably, the operating conditions of the circulating heater in the heat supply system include: an operating temperature of 575-685°C, preferably 610-640°C; and an operating pressure of 0.02 to 2 MPaG, preferably 0.05 to 0.1 MPaG.

[0077] According to the present invention, preferably, the pressurization conditions of the circulating gas compressor in the heat supply system include: an operating pressure of 0.02 to 2 MPaG, preferably 0.05 to 0.1 MPaG.

[0078] In this invention, the shell side of the isothermal tubular reactor uses an inert heat-conducting fluid, preferably circulating nitrogen, to prevent air from permeating into the isothermal tubular reactor and improve system safety.

[0079] According to the present invention, preferably, the operating conditions of the air compressor in the regeneration system include: an operating pressure of -0.05 to 1 MPaG, preferably 0 to 0.5 MPaG; and an operating temperature of 80-200°C, preferably 100-150°C.

[0080] According to the present invention, preferably, the operating conditions of the air heater in the regeneration system include: a heating temperature of 550-610°C, preferably 570-590°C.

[0081] In this invention, preferably, the method further includes switching between a dehydrogenation isothermal tubular reactor and a regeneration isothermal tubular reactor. By switching between the dehydrogenation isothermal tubular reactor and the regeneration isothermal tubular reactor, the reaction system and the regeneration system are switched. The dehydrogenation catalyst in the reaction system, whose activity has decreased after the alkane dehydrogenation reaction, is regenerated. The regenerated catalyst in the regeneration system is then used for the alkane dehydrogenation reaction, thus achieving continuous alkane dehydrogenation reaction and catalyst regeneration.

[0082] According to a preferred embodiment of the present invention, the alkane dehydrogenation reaction is carried out in... Figure 1 The reaction takes place in the system shown. The alkane feed is heated by the feed heat exchanger 1 and the feed heater 2, and then sent to the tube side of the dehydrogenation isothermal tubular reactor 3A for alkane dehydrogenation reaction. The product gas obtained from the reaction enters the feed heat exchanger 1 to continue heat exchange with the alkane feed.

[0083] Heating System: The inert heat transfer fluid is compressed by the circulating gas compressor 4 and then heated by the circulating heater 5. The heated inert heat transfer fluid is then split into a branch pipe (not shown in the figure). One portion is sent to the shell side of the dehydrogenation isothermal tubular reactor 3A to provide heat for the alkane dehydrogenation reaction. From the shell side outlet of the dehydrogenation isothermal tubular reactor 3A, it is sent to the steam generator 11 through a confluence pipe (not shown in the figure) to produce steam. After reducing the temperature of the inert heat transfer fluid, it is circulated back to the circulating gas compressor 4. The other portion of the inert heat transfer fluid split from the branch pipe is sent to the shell side of the regeneration isothermal tubular reactor 3B to provide heat for the regeneration of the dehydrogenation catalyst. From the shell side outlet of the regeneration isothermal tubular reactor 3B, it is sent to the steam generator 11 through a confluence pipe to produce steam.

[0084] Regeneration System: After being compressed by air compressor 6, air enters air feed heat exchanger 7 to exchange heat with the regenerated flue gas at the outlet of regeneration isothermal tubular reactor 3B. After being heated by air heater 10, the regenerated flue gas enters regeneration isothermal tubular reactor 3B to regenerate the catalyst and obtain regenerated flue gas. After entering air feed heat exchanger 7 to exchange heat with air, the regenerated flue gas is cooled by regenerated flue gas cooler 8 and then enters chimney 9 to be discharged.

[0085] The present invention will be described in detail below through examples and comparative examples. Unless otherwise specified, all reagents used in the following examples and comparative examples are commercially available.

[0086] Propane conversion rate = (Propane conversion amount / Propane feed amount) × 100%;

[0087] Propylene selectivity = Amount of alkane produced to propylene / Propane conversion × 100%.

[0088] Example 1

[0089] exist Figure 1 The system shown performs propane dehydrogenation and dehydrogenation catalyst regeneration. The system is equipped with two isothermal tubular reactors. The dehydrogenation isothermal tubular reactor 3A is used for the propane dehydrogenation reaction (one reaction time is 30 min), and the regeneration isothermal tubular reactor 3B is used for the regeneration of the dehydrogenation catalyst (one purging, regeneration and reduction time is 30 min). The isothermal tubular reactors are operated in a cycle through time control.

[0090] In the propane dehydrogenation reaction stage, the propane feedstock (40℃, 0.5MPaG, 32.5t / h) is heated to 590℃ by the feed heat exchanger 1 and the feed heater 2 in sequence before entering the tube side of the dehydrogenation isothermal tubular reactor 3A to carry out the propane dehydrogenation reaction (590℃, -0.05MPaG). The product gas is heated to 130℃ by the feed heat exchanger 1 and then sent to the downstream separation unit (not shown in the figure).

[0091] The inert heat conducting fluid in the heating system is circulating nitrogen (820 t / h, 500°C, 0.01 MPaG), which is pressurized to 0.08 MPaG by a circulating gas compressor 4, heated to 640°C by a circulating heater 5, and then sent to the shell side of the dehydrogenation isothermal tubular reactor 3A through a shunt pipe (not shown in the figure) to provide heat for the propane dehydrogenation reaction, and then returned to the circulating gas compressor 4 through a merging pipe (not shown in the figure) for recycling.

[0092] During regeneration, fresh air (140 t / h) is pressurized to 0.12 MPaG, 120°C by an air compressor 6, heat exchanged with the regenerated flue gas from the outlet of the regeneration isothermal tubular reactor 3B in the air inlet and outlet heat exchanger 7, heated to 590°C by an air heater 10, and then enters the regeneration isothermal tubular reactor 3B for catalyst regeneration, obtaining regenerated catalyst and regenerated flue gas. The regenerated flue gas enters the air inlet and outlet heat exchanger 7 through the outlet of the tube side of the regeneration isothermal tubular reactor 3B, exchanges heat with the compressed fresh air, is cooled to 130°C by a regenerated flue gas cooler 8, and is discharged through a chimney 9.

[0093] Through time sequence control, the dehydrogenation isothermal tubular reactor 3A and the regeneration isothermal tubular reactor 3B are switched, and the circulation operation is carried out for 500 h, the propane conversion rate is 57.81%, and the propylene selectivity is 87.45%.

[0094] Example 2

[0095] In the system shown in Figure 2 The propane dehydrogenation and dehydrogenation catalyst regeneration are carried out in the system, which is provided with four isothermal tubular reactors, the dehydrogenation isothermal tubular reactors 3A and 3B are used for propane dehydrogenation reaction (the reaction time is 30 min), the regeneration isothermal tubular reactors 3C and 3D are used for dehydrogenation catalyst regeneration (the time required for one-time purging, regeneration and reduction is 30 min), and the isothermal tubular reactors are operated in circulation through time sequence control.

[0096] In the propane dehydrogenation reaction stage, the propane feedstock (40°C, 0.5 MPaG, 65 t / h) is heat exchanged in turn by the inlet and outlet heat exchanger 1 and heated to 590°C by the feed heater 2, and then enters the tube side of the dehydrogenation isothermal tubular reactors 3A and 3B, respectively, to carry out propane dehydrogenation reaction (590°C, -0.05 MPaG), and the product gas is heat exchanged to 130°C by the inlet and outlet heat exchanger 1 and then sent to the downstream separation unit (not shown in the figure).

[0097] The inert heat transfer fluid in the heat supply system is circulating nitrogen (1640 t / h, 500 ℃, 0.01 MPaG). After being pressurized to 0.08 MPaG by the circulating gas compressor 4 and heated to 640 ℃ by the circulating heater 5, it is sent to the shell side of the dehydrogenation isothermal tubular reactors 3A and 3B through the split pipe (not shown in the figure) to provide heat for the propane dehydrogenation reaction. After that, it is returned to the circulating gas compressor 4 through the confluence pipe (not shown in the figure) for recycling.

[0098] During the regeneration process, fresh air (280t / h) is pressurized to 0.12MPaG and 120℃ by air compressor 6, and then exchanges heat with the regeneration flue gas from the outlet of regeneration isothermal tubular reactors 3C and 3D through air inlet / outlet heat exchanger 7. It then enters air heater 10 and is heated to 590℃ before entering regeneration isothermal tubular reactors 3C and 3D for catalyst regeneration, resulting in regenerated catalyst and regeneration flue gas. The regeneration flue gas enters air inlet / outlet heat exchanger 7 through the tube-side outlet of regeneration isothermal tubular reactors 3C and 3D to exchange heat with compressed fresh air. After being cooled to 130℃ by regeneration flue gas cooler 8, it is discharged through chimney 9.

[0099] By controlling the timing, the dehydrogenation isothermal tubular reactors 3A and 3B and the regeneration isothermal tubular reactors 3C and 3D were switched, and the reaction was cyclically operated for 500 hours. The propane conversion rate was 57.81%, and the propylene selectivity was 87.45%.

[0100] Example 3

[0101] exist Figure 1 The system shown performs propane dehydrogenation and dehydrogenation catalyst regeneration, following the method of Example 1, except that a steam generator 11 is not installed. The circulating nitrogen from the outlets of the dehydrogenation isothermal tubular reactor 3A and the regeneration isothermal tubular reactor 3B is circulated through a confluence pipe to the circulating gas compressor 4 for pressurization.

[0102] By controlling the timing, switching between the dehydrogenation isothermal tubular reactor 3A and the regeneration isothermal tubular reactor 3B, and cyclically operating the reaction for 500 hours, the propane conversion rate was 59.21% and the propylene selectivity was 84.31%.

[0103] Comparative Example 1

[0104] The system is equipped with two fixed-bed batch reactors, one for propane dehydrogenation reaction and the other for dehydrogenation catalyst regeneration. The reactors are operated in a cyclic manner through time-series control.

[0105] In the reaction stage, the propane feedstock (40℃, 0.5MPaG, 32.5t / h) is heated to 640℃ by passing through the feed-in and feed-out heat exchanger and the feed-in electric heater in turn, and then enters the reactor to perform the propane dehydrogenation reaction (640℃, -0.05MPaG). The temperature of the catalyst bed decreases to 570℃ as the reaction proceeds, and the generated product gas is sent to the downstream separation unit after passing through the feed-in and feed-out heat exchanger.

[0106] In the regeneration stage, the fresh air (140t / h) is pressurized to 0.12MPaG, 120℃ by the compressor, and then heated to 650℃ by passing through the air feed-in and feed-out heat exchanger and the air heater in turn, and then enters the catalyst regeneration reactor to perform the catalyst regeneration. At the same time, the catalyst bed is heated to 600℃ to provide heat for the subsequent reaction, and the generated high-temperature regeneration flue gas is discharged after heat exchange by the chimney.

[0107] After the reaction for 500h, the propane conversion rate is 49.81%, and the propylene selectivity is 87.73%.

[0108] It can be known from the above example results that, by using the alkane dehydrogenation reaction and regeneration system of the present application, the propane single-pass conversion rate can be more than 55.0% and the propylene selectivity can be more than 80.0% by controlling the reaction system temperature within the optimal reaction temperature range.

[0109] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept range of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as the disclosed content of the present application, and all fall within the protection scope of the present application.

Claims

1. A system for alkane dehydrogenation reaction and catalyst regeneration, characterized in that, The system includes: a heat supply system, a reaction system, and a regeneration system; The reaction system includes: a feed heat exchanger and a dehydrogenation isothermal tubular reactor; The dehydrogenation isothermal tubular reactor is used for alkane dehydrogenation reactions. The feed heat exchanger is used to exchange heat between the alkane feed and the product gas at the outlet of the dehydrogenation isothermal tubular reactor. The heat supply system is used to provide heat to the shell side of the dehydrogenation isothermal tubular reactor via an inert heat-conducting fluid. The regeneration system includes: a regeneration isothermal tubular reactor and an air inlet / outlet heat exchanger; The regenerating isothermal tubular reactor is used for catalyst regeneration; The air inlet / outlet heat exchanger is used to exchange heat between compressed air and the regenerated flue gas at the outlet of the regenerated isothermal tubular reactor.

2. The system according to claim 1, wherein, The reaction system includes at least one dehydrogenation isothermal tubular reactor, preferably 2-10 dehydrogenation isothermal tubular reactors; Preferably, the reaction system further includes a feed heater, the inlet of which is connected to the outlet of the feed heat exchanger, and the outlet of which is connected to the tube side of the dehydrogenation isothermal tubular reactor. Preferably, the inert heat-conducting fluid is an inert heat-conducting gas, preferably circulating nitrogen.

3. The system according to claim 1 or 2, wherein, The heat supply system includes a circulating gas compressor, which is used to compress an inert heat-conducting fluid to provide heat to the shell side of the dehydrogenation isothermal tubular reactor. Preferably, the heating system further includes a circulating heater, the inlet of which is connected to the outlet of the circulating gas compressor, and the outlet of which is connected to the shell side of the dehydrogenation isothermal tubular reactor, for heating the inert heat transfer fluid compressed by the circulating gas compressor.

4. The system according to any one of claims 1-3, wherein, The regeneration system also includes an air compressor, which is used to pressurize air to obtain compressed air; Preferably, the regeneration system further includes an air heater, the outlet of which is connected to the tube-side inlet of the regeneration isothermal tubular reactor for heating the outlet material of the air feed heat exchanger. Preferably, the regeneration system includes at least one regeneration isothermal tubular reactor, and more preferably, it includes 2-10 regeneration isothermal tubular reactors.

5. The system according to any one of claims 1-4, wherein, The regeneration system also includes a regeneration flue gas cooler, which is connected to the outlet of the air inlet / outlet heat exchanger and is used to cool the regeneration flue gas after heat exchange.

6. The system according to any one of claims 1-5, wherein, The system also includes a steam generator for removing heat from the inert thermal fluid at the outlet of the dehydrogenation isothermal tubular reactor and the regeneration isothermal tubular reactor.

7. A method for alkane dehydrogenation reaction and catalyst regeneration, characterized in that, The method is performed in the system according to any one of claims 1-6, and the method includes the following steps: Heat is supplied to the reaction system and the regeneration system by the inert heat transfer fluid of the heating system, respectively, to carry out the alkane dehydrogenation reaction of the alkane feedstock in the reaction system to obtain product gas; the dehydrogenation catalyst after the alkane dehydrogenation reaction in the regeneration system is regenerated. The method further includes exchanging heat between the product gas from the dehydrogenation isothermal tubular reactor in the reaction system and the alkane feedstock, and exchanging heat between the compressed air in the regeneration system and the regeneration flue gas from the regeneration isothermal tubular reactor.

8. The method according to claim 7, wherein, The alkane dehydrogenation reaction is carried out in the presence of a dehydrogenation catalyst; Preferably, the conditions for the alkane dehydrogenation reaction include: an operating temperature of 550-610℃, more preferably 570-590℃; and an operating pressure of -0.05 to 0.5 MPaG, more preferably -0.05 to 0.05 MPaG. Preferably, the alkane feedstock is a low-carbon alkane, preferably propane and / or butane.

9. The method according to claim 7 or 8, wherein, The operating conditions of the circulating heater in the heat supply system include: an operating temperature of 575-685℃, preferably 610-640℃; and an operating pressure of 0.02 to 2 MPaG, preferably 0.05 to 0.1 MPaG. Preferably, the pressurization conditions of the circulating gas compressor in the heat supply system include: an operating pressure of 0.02 to 2 MPaG, preferably 0.05 to 0.1 MPaG.

10. The method according to any one of claims 7-9, wherein, The operating conditions of the air compressor in the regeneration system include: operating pressure of -0.05 to 1 MPaG, preferably 0 to 0.5 MPaG; and operating temperature of 80-200℃, preferably 100-150℃. Preferably, the operating conditions of the air heater in the regeneration system include a heating temperature of 550-610℃, more preferably 570-590℃.

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