Isobutane dehydrogenation device and dehydrogenation system

Abstract

The application discloses an isobutane dehydrogenation device and a dehydrogenation system, relates to the technical field of isobutane dehydrogenation, and comprises a reactor, wherein the reactor is in a horizontal cylinder structure, and an inner cavity of the reactor is divided into a catalytic reaction zone at an upper portion and a feed bottom bin at a lower portion; a feed channel is fixedly installed on a side wall of the reactor, and the feed channel comprises at least two feed branch pipes which are independently communicated to the inner portion of the reactor. The application can effectively inhibit serious coking under low load by dynamically regulating and controlling a feed area, can monitor a feed load in real time through a DCS control system and a multi-target variable domain distribution unit, can automatically close or reduce a side edge feed branch pipe under a low load working condition, can force air flow to converge in a core material area, can make the volume of catalyst participating in reaction be reduced, can make local superficial air speed return to a safe interval in which coking does not occur, can shorten the residence time of materials in a high-temperature zone, and thus can effectively inhibit deep cracking and greatly reduce the coke formation rate.

Description

Technical Field

[0001] This invention relates to the field of isobutane dehydrogenation technology, specifically to an isobutane dehydrogenation device and system for the dehydrogenation of isobutene, which can reduce the problem of coke deposition during the dehydrogenation process. Background Technology

[0002] Isobutylene, as an important basic chemical raw material, is widely used in methyl tert-butyl ether (MTBE), polymer materials, and fine chemicals. Currently, one of the main industrial processes for producing isobutylene is light hydrocarbon dehydrogenation technology. Among them, the CATOFIN process package is a typical cyclic operation fixed-bed dehydrogenation process, and its unit is usually designed as a combined dehydrogenation mode for propane and isobutane. In a standard combined dehydrogenation unit, multiple dehydrogenation reactors (such as R-1001 to R-1004) alternately carry out dehydrogenation reactions, purging, regeneration, and reduction cycles to achieve continuous production.

[0003] For example, Chinese patent document CN207294637U discloses an isobutane dehydrogenation device, including a dehydrogenation tower and a separation tower. The bottom of the dehydrogenation tower has a first outlet connected to a second inlet of the separation tower. The first inlet of the dehydrogenation tower is connected to a heating device. The top of the dehydrogenation tower has a hydrogen outlet connected to an air cooler. The top of the separation tower has an isobutene outlet. The bottom of the separation tower has a second outlet connected to the dehydrogenation tower. A reboiler is provided between the second outlet and the dehydrogenation tower. Its advantages are: simple structure, high utilization rate of isobutane, and high purity of collected gas. However, this scheme mainly relies on the air cooler for cooling and hydrogen reflux control. The heat exchange efficiency of the air cooler is easily affected by the season and ambient temperature (especially high temperatures in summer), which may lead to unstable reflux temperature, thus affecting the reduction effect of the catalyst. For example, Chinese patent document CN210009764U discloses an isobutane dehydrogenation device, including: a washing tank, an exhaust pipe, an inlet pipe, an outlet, a water tank, a return water pipe, a water inlet pipe, nozzles, and a slag discharge port. Isobutene enters the washing tank through the inlet pipe. The pump draws aqueous solution from the water tank and sends it to the water inlet pipe through a connecting pipe. The water inlet pipe sprays the aqueous solution into the cavity of the washing tank through various nozzles. The aqueous solution dissolves the aldehydes and ketones carried in the isobutene. The aqueous solution flows back to the water tank through the return water pipe to achieve circulation until the aqueous solution is saturated. The washed isobutene is discharged through the exhaust pipe. The catalyst particles carried by the isobutene will gradually deposit at the bottom of the washing tank. When there is too much deposit at the bottom, the shut-off valve is opened, driving the guide rod to move horizontally, causing the push plate to move towards the slag discharge port. The rubber plate at the bottom of the push plate scrapes off the impurities at the bottom of the washing tank and pushes them to the slag discharge port, and finally discharges them through the slag discharge pipe, which can realize the collection and reuse of the catalyst. It also effectively avoids pipeline blockage. However, this solution involves setting up reciprocating mechanical push plates, guide rods and rubber plates inside the chemical washing tank (which is usually corrosive or under certain pressure). The rubber parts are very prone to aging and wear in the chemical environment, and the dynamic sealing ring of the guide rod is also prone to leakage, resulting in high maintenance costs and increased failure rate. For example, Chinese patent document CN214949987U discloses a high-efficiency cooling isobutane dehydrogenation device, comprising: a dehydrogenation device cold exhaust circulation pool; a dehydrogenation device cold exhaust pipe disposed inside the dehydrogenation device cold exhaust circulation pool; and a cold air blower disposed at the top of the dehydrogenation device cold exhaust circulation pool. Linkage structures are fixedly installed on both sides inside the dehydrogenation device cold exhaust circulation pool, and the linkage structures include fixing grooves. This utility model provides a high-efficiency cooling isobutane dehydrogenation device that uses the cold air blower to cool the dehydrogenation device. The cooling system works in conjunction with the circulating water in the hydrogen unit's cold runner circulation pool to further cool the cooling pipes of the dehydrogenation unit. This improves the cooling effect on the dehydrogenation unit's cold runner pipes, reduces circulating water consumption, and minimizes water waste. It also reduces the energy consumption of the pumps extracting water from the hydrogen unit's cold runner circulation pool. However, this design introduces the motor, pulleys, and threaded rod transmission mechanism to the bottom and sides of the pool, and performs the mechanical lifting and lowering of the condenser pipes underwater. This places extremely high demands on the equipment's waterproofing, corrosion resistance, and scale prevention. The harsh environment of the chemical water pool makes the complex mechanical transmission highly susceptible to jamming or damage. However, in actual production, a serious coking problem arises due to the conflict between the feed space velocity and downstream processing capacity: when the unit switches to single isobutane dehydrogenation, the reactor feed flow rate is limited by the downstream compressor, fractionation system, or cold box processing capacity, forcing the feed space velocity to be maintained at a low level. According to dehydrogenation reaction kinetics, low space velocity means that the reactants have too long a residence time in the high-temperature catalyst bed, making them highly susceptible to deep cracking side reactions, resulting in a large amount of coke deposition on the reactor bed. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and solve the technical problem that the long residence time of reactants in the high-temperature catalyst bed leads to the formation of a large amount of coke deposits in the reactor bed, and to provide an isobutane dehydrogenation device and dehydrogenation system to solve the problems mentioned above in the background art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: An isobutane dehydrogenation device includes a reactor, which is a horizontally placed cylindrical structure with its interior divided into an upper catalytic reaction zone and a lower feed hopper; a feed channel, fixedly installed on the side wall of the reactor, including at least two independent feed branch pipes connected to the interior of the reactor, each feed branch pipe equipped with a flow control valve assembly; and a flow distribution matrix mechanism, fixedly installed inside the reactor, used to radially disperse the gas flow entering the reactor into the catalyst after dispersion and compensation by the flow distribution matrix mechanism; and a cross-zone thermal balance mechanism, installed above the flow distribution matrix mechanism and spanning different reaction sites of the catalytic reaction zone, used to balance the flow distribution matrix mechanism in the reactor. During the hydrogen reaction, phase change heat transfer balance is achieved for heat in different regions; and a DCS control system is connected to each flow control valve group. The DCS control system is equipped with a multi-objective variable domain allocation unit, which is configured to: based on the acquired feed load and bed temperature data, call a global evaluation model that includes a weighted term for the overall bed conversion rate and a penalty term for local coking risk, and generate variable domain allocation instructions to drive the flow control valve groups to act independently. The feed hopper includes a core material zone located in the middle of the reactor cross-section and edge material zones located on both sides of the core material zone, and at least two feed branch pipes are connected to the core material zone and the edge material zone respectively.

[0006] The construction logic of the global evaluation model described in this invention is as follows: A coking air velocity safety threshold is set. When the expected value of the local apparent air velocity calculated under uniform feeding across the entire region is greater than the coking air velocity safety threshold, the weight of the local coking risk penalty term approaches zero, and the variable-domain allocation instruction aims to balance feeding across the entire region and maximize the weight of the whole bed conversion rate. When the expected value of the local apparent air velocity calculated under uniform feeding across the entire region is less than the coking air velocity safety threshold, the weight of the local coking risk penalty term increases sharply and non-linearly, and the variable-domain allocation instruction is forced to prioritize increasing the local apparent air velocity in the core material area. By reducing the opening of the flow control valve group in the edge material area, the feed airflow is forced to converge to the core area.

[0007] The diffuser matrix mechanism of the present invention includes a partition plate fixed laterally in the inner cavity of the reactor, and a plurality of longitudinally extending guide tubes are distributed in a staggered array on the partition plate; the top of each guide tube is fixedly connected with a cap for blocking vertical airflow, and a plurality of radial diffuser holes are equidistantly and staggered along the axial direction on its circumferential outer wall surface, and a blocking structure for intercepting catalyst particles is fixed inside the guide holes.

[0008] The inner diameter of each guide tube in this invention is configured to be negatively correlated with the thickness of the catalyst bed corresponding to its location. Along the radial direction of the reactor cross-section, the inner diameter of multiple guide tubes is set to decrease in a gradient from the core material zone to the edge material zone.

[0009] The blocking structure of the present invention includes a fixing ring embedded in the inner periphery of the guide hole, a sliding frame slidably connected to the inner ring of the fixing ring, a connecting rod extending from the back of the sliding frame, an auxiliary spring providing axial preload sleeve on the outer periphery of the connecting rod, and the distal end of the auxiliary spring being limited by a limiting frame fixed to the end of the connecting rod; a plurality of venting grooves are evenly opened along the circumference of the sliding frame, and each venting groove is covered with a venting mesh for blocking catalyst fragments.

[0010] The cross-zone thermal balance mechanism of the present invention includes two main pipes symmetrically arranged above the partition plate. The two main pipes form a medium interaction loop through a connecting conduit. Each main pipe has several branch pipes equidistantly distributed along the axial direction on its sidewall. Each branch pipe is connected to a micro-network for three-dimensional heat exchange deep inside the catalyst bed at one end away from its main pipe.

[0011] The cross-regional thermal balance mechanism of the present invention has a phase change heat transfer medium with high thermal conductivity sealed inside its cavity.

[0012] The cross-zone thermal balancing mechanism of the present invention also includes a support frame fixed above the partition plate. The top of the support frame is fixedly connected to the cross-zone thermal balancing mechanism. The cross-section of the main pipe is arranged in a streamlined teardrop shape, and the rounded end of the teardrop-shaped cross-section faces the air intake direction of the feed hopper.

[0013] The present invention also provides a dehydrogenation system, comprising: S1, Load sensing and dynamic zoning stage; Load monitoring: The system collects the total flow rate of the feedstock isobutane in real time through sensors installed on the feed channel. ; Threshold determination: The multi-target variable domain allocation unit in the DCS calls the global evaluation model. When the calculated global average airspeed falls below the anti-focus airspeed safety threshold, the threshold is determined. At that time, the system determined that the system had entered the "coking risk zone"; Variable Domain Command: The system generates a variable domain allocation command, which drives the flow control valve assembly to perform actions. By closing or reducing the branch pipes in the edge material zone, the raw material gas is forced to converge into the core material zone, artificially reducing the volume of the active catalyst. This allows the local apparent airspeed to return to a safe range; S2, pressure drop compensation and precision gas distribution stage and radial dispersion and catalytic reaction stage; The gas flows to the diffuser matrix mechanism, which performs gradient drag compensation. S3, the stage of cross-regional thermal balance and energy replenishment; Temperature difference sensing and latent heat transfer, through the setting of a cross-zone thermal balancing mechanism, maintain the temperature difference balance between the core area (cold end) and the edge material area (hot end).

[0014] Due to the adoption of the above technical solution, the technical progress achieved by this invention compared to the prior art is as follows: 1. Compared with the prior art, the present invention effectively suppresses severe coking under low load by dynamically adjusting the feeding area. The DCS control system and multi-objective variable domain distribution unit monitor the feeding load in real time. Under low load conditions, the system can automatically close or reduce the edge feeding branches, forcing the airflow to converge in the core material area. By reducing the volume of catalyst participating in the reaction, the local apparent space velocity returns to the safe range of non-coking, shortening the residence time of materials in the high-temperature zone, thereby effectively suppressing deep cracking and significantly reducing the coke generation rate.

[0015] 2. Compared with the prior art, the present invention eliminates reaction dead zones and channeling through multi-dimensional radial diffusion design. The built-in diffusion matrix mechanism, through the guide tube with a cap, reconstructs the "one-dimensional vertical jet" that is prone to local fluidization into a gentle and wide-coverage "three-dimensional radial diffusion flow". The directional guidance and delivery blocks the shortcut of gas flow to the weak edge of the catalyst, and forces the gas to penetrate the deep central bed uniformly. This eliminates the dead zone and vertical channeling phenomenon of the side wall effect unique to horizontal reactors, and greatly improves the utilization rate of catalyst.

[0016] 3. Compared with the prior art, the present invention achieves full-section flow field equilibrium through gradient mechanical resistance compensation. The inner diameter of each guide tube in the diffuser matrix structure is set in a gradient decreasing manner from the core material area to the edge material area, that is, it is negatively correlated with the thickness of the catalyst bed above. Through this non-uniform distribution of tube diameter, a high pressure drop barrier is pre-constructed in the edge area where the catalyst is thinner, so that the sum of the mechanical resistance of the guide tube and the resistance of the bed remains constant in the cross section, ensuring that the material has a completely consistent residence time (equal space velocity) in different domains, effectively eliminating edge hot spots and improving the single-pass conversion rate of isobutylene.

[0017] 4. Compared with the prior art, the present invention achieves online self-cleaning without disassembly through pneumatic adaptive oscillation. The guide hole is equipped with a floating sliding frame with an auxiliary spring and a breathable net. This structure is driven by airflow. During the gas blowing process, the sliding frame will generate high-frequency floating and vibration. This microscopic shear stress can directly tear and peel off the rigid coke and dust shell attached and plated on the surface of the breathable net. The peeled material is then blown into the reaction zone by high-speed airflow, thereby eliminating the tedious steps of stopping the tank to open and manually disassembling and cleaning, and ensuring the long-term stable operation of the diffuser matrix.

[0018] 5. Compared with the prior art, the present invention eliminates local thermal stress and extends equipment life by cross-zone phase change heat transfer balance. The cross-zone thermal balance mechanism utilizes the phase change heat transfer medium to achieve efficient energy exchange between the core zone (cold end) and the edge material zone (hot end). During low-load variable-domain operation, the micro-pipe network in the edge zone absorbs high-temperature sensible heat and transports it across zones to the core zone where severe local temperature drop occurs through the main pipe, releasing latent heat. This ensures that the catalyst is always maintained within the optimal dehydrogenation thermodynamic temperature window, and also mitigates local supercooling caused by zoned feeding, eliminating the risk of thermal stress inside the equipment, and greatly extending the operating cycle of the device and the service life of subsequent equipment. Attached Figure Description

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the overall device structure of the present invention; Figure 2 This is a partial half-section structural diagram of the present invention; Figure 3 This is a schematic diagram of the internal structure of the present invention; Figure 4 This is a schematic diagram of the flow guide tube structure of the present invention; Figure 5 This is a schematic diagram of the barrier structure of the present invention; Figure 6 This is a schematic diagram of the explosive structure of the barrier structure of the present invention; Figure 7This is a schematic diagram of the cross-regional thermal balance mechanism of the present invention.

[0021] In the diagram: 1. Reactor; 2. Feed channel; 3. Diffuser matrix mechanism; 4. Cross-zone thermal balance mechanism; 5. Divider plate; 6. Guide pipe; 7. Cover; 8. Guide hole; 9. Barrier structure; 10. Fixing ring; 11. Sliding frame; 12. Connecting rod; 13. Auxiliary spring; 14. Limiting frame; 15. Air permeable mesh; 16. Main stream pipe; 17. Diverter pipe; 18. Micro-pipe network. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the embodiments.

[0023] Example 1 like Figures 1-3 As shown, this invention provides an isobutane dehydrogenation device and system, comprising: a reactor 1, which is a horizontally placed cylindrical structure, its inner cavity divided into an upper catalytic reaction zone and a lower feed hopper; a feed channel 2, fixedly installed on the side wall of the reactor 1, the feed channel 2 including at least two independent feed branch pipes connected to the interior of the reactor 1, each feed branch pipe being equipped with a flow control valve group; and further comprising: a diffuser matrix mechanism 3, fixedly installed inside the reactor 1, used to radially diffuse the gas flow entering the reactor 1 into the catalyst interior after dispersion compensation by the diffuser matrix mechanism 3; and a cross-zone thermal balance mechanism 4, installed above the diffuser matrix mechanism 3 and spanning the catalytic reaction zone. Different reaction sites in the zone are used to balance the heat transfer of different regions during the dehydrogenation reaction; and a DCS control system is connected to each flow control valve group. The DCS control system is equipped with a multi-objective variable domain allocation unit, which is configured to: based on the acquired feed load and bed temperature data, call a global evaluation model that includes a weighted term for the full bed conversion rate and a penalty term for local coking risk, and generate variable domain allocation instructions to drive the flow control valve groups to act independently. The feed hopper includes a core material zone located in the middle of the reactor cross-section and edge material zones located on both sides of the core material zone. At least two feed branch pipes are connected to the core material zone and the edge material zone respectively.

[0024] In this embodiment, the device uses a DCS control system to collect feed load and bed temperature field data in real time and inputs them into a built-in global evaluation model. It can dynamically adjust the effective reaction domain when the total flow fluctuates by using a preset anti-coking space velocity safety threshold. Under low load conditions, the system recognizes the surge in the weight of the coking penalty term caused by the decrease in global space velocity and then triggers a domain change command to close the edge feed branch and force the airflow to converge in the core material area. This artificially reduces the volume of the catalyst participating in the reaction at the physical level, so that the local apparent space velocity returns to the safe range of non-coking. At the same time, the flow distribution matrix mechanism 3 uses a gradient variable inner diameter pipeline to mechanically compensate for the geometric resistance deviation of the horizontal container. In conjunction with the cross-zone thermal balance mechanism 4, the latent heat of phase change is used to realize the passive energy exchange between the hot and cold ends, ensuring the uniformity of the flow field and the stability of thermal balance throughout the cross section during the domain change process. Through macroscopic control logic of reducing area and maintaining flow rate, the system can shorten the residence time of materials in the high-temperature zone without increasing the downstream load, suppress deep cracking and reduce coke generation rate. At the same time, the diffused flow matrix mechanism 3 fundamentally eliminates the dead zone of the side wall effect and the vertical channeling phenomenon unique to horizontal reactors, greatly improving catalyst utilization and isobutylene selectivity. In addition, the cross-zone thermal balance mechanism 4 effectively suppresses local supercooling caused by zoned feeding, eliminates the risk of thermal stress inside the equipment, and extends the operating cycle of the unit and the service life of subsequent heat exchange equipment.

[0025] like Figure 1 As shown, the preferred construction logic of the global evaluation model is as follows: Set a safe airspeed threshold for anti-fogging; When the expected value of the local apparent space velocity calculated under the uniform feeding of the whole domain is greater than the anti-coking space velocity safety threshold, the weight of the local coking risk penalty term approaches zero, and the variable domain allocation instruction aims to balance the feeding of the whole domain and maximize the weight of the conversion rate of the whole bed. When the expected value of the local apparent space velocity calculated under the uniform feeding of the whole domain is less than the anti-coking space velocity safety threshold, the weight of the local coking risk penalty term increases sharply in a non-linear manner. The variable domain allocation command is forced to prioritize increasing the local apparent space velocity of the core material area. By reducing the opening of the flow control valve group in the edge material area, the feed airflow is forced to converge to the core area.

[0026] In this embodiment, in the isobutane dehydrogenation reaction, the apparent space velocity (gas flow velocity) of the feed is the dividing line that determines whether the unit can operate for a long period of time. When the dehydrogenation unit is forced to reduce the total feed load due to downstream processing capacity limitations or capacity adjustments, if the traditional "uniform feeding across the entire reactor" mode is followed, the apparent space velocity across the entire reactor cross-section will decrease synchronously.

[0027] Once the gas flow rate falls below the safe lower limit required by the reaction kinetics, the residence time of isobutane in the high-temperature catalyst bed will be seriously exceeded, which will easily trigger deep cracking side reactions, resulting in a large amount of coke deposition on the catalyst surface. This "full-area coking" caused by low load will quickly block the bed and cause system pressure buildup, ultimately forcing the entire unit to shut down unplanned for coking removal. Traditional control logic lacks adaptive spatial intervention methods to cope with load fluctuations and cannot maintain high flow rate under low gas volume. Hardware layout and partitioning: The inner cavity of reactor 1 is divided into an upper reaction zone and a lower bottom chamber. In order to achieve precise control, the bottom chamber is physically isolated into a core material zone located on the axis and an edge material zone located on both sides of the arc. The feed channel 2 is connected to the above-mentioned zones through independent branch pipes, and each branch pipe is equipped with a flow control valve group. Global evaluation model logic: The system collects the total feed flow rate in real time. and the bed temperature in each region. The multi-objective variable domain allocation unit runs the following scoring function:

[0028] in, The expected conversion rate of the entire bed is represented by the following term. To assign a penalty weight to the risk of localized low airspeed coking (CRI), the system sets a safe airspeed threshold for coking resistance. , The weighting coefficients for the expected conversion rate term. The weighting coefficient for the temperature difference penalty term. For local temperature differences; Dynamic control process: Comfort zone: Apparent space velocity (SV) under conditions of sufficient total load and uniform feed distribution across the entire area. At that time, the weight of the penalty item Approaching zero, the system prioritizes items that maximize conversion rate. To achieve this goal, maintain balanced feeding across the entire area; Forced Correction Zone: When downstream processing capacity is limited, leading to a decrease in total load. Descending, predicted airspeed drop below At that time, the weight of the penalty item The growth rate increases rapidly and non-linearly; therefore, an exponential growth model is preferred. At this point, the evaluation model score E drops rapidly, triggering a binocular-linked forced allocation command: the system actively reduces or closes the valve groups in the edge material zone, forcibly converging the airflow to the core material zone, thereby reducing the volume of the active catalyst. This causes local airspeed By returning to the safe threshold, the conversion rate in the edge area is "sacrificed" under low load conditions in exchange for the overall non-coking safety of the device.

[0029] Example 2 like Figures 3-5 As shown, based on Embodiment 1, the present invention provides a technical solution: preferably, the diffuser matrix mechanism 3 includes a partition plate 5 that is laterally fixed in the inner cavity of the reactor 1, and a plurality of longitudinally extending guide pipes 6 are distributed in a staggered array on the partition plate 5; the top of each guide pipe 6 is fixedly connected to a cap 7 for blocking vertical airflow, and a plurality of radial diffuser holes 8 are equidistantly and staggered along the axial direction on its circumferential outer wall surface, and a blocking structure 9 for intercepting catalyst particles is fixed inside the guide hole 8.

[0030] In this embodiment, in fluid dynamics, gas seeks the shortcut of least resistance. Without intervention, gas entering from the bottom will quickly rush to the two sides (the thinnest part of the catalyst) and escape instantly; while the thick catalyst zone in the middle will not have any gas flow, forming a huge reaction "dead zone". Therefore, when the isobutane gas flow passes through the partition plate 5 from bottom to top from the feed hopper, it encounters the staggered array of guide pipes 6. The gas flow accelerates upward inside the guide pipes 6, but is rigidly blocked by the solid cap 7 at the pipe opening. Its vertical upward kinetic energy is forcibly cut off and it turns 90 degrees. Subsequently, the gas flow is forced to exit horizontally from the staggered guide holes 8 on the side wall of the guide pipes 6. The original "one-dimensional vertical jet," which was prone to local fluidization, was reconstructed into a gentle and wide-coverage "three-dimensional radial diffused flow." This allows the gas flow to penetrate upwards in a planar form. The isobutane gas flow is rapidly guided to the catalyst reaction zone through the guide pipe 6 and the guide hole 8. The barrier structure 9 prevents the catalyst from entering the interior of the guide pipe 6, increasing the smoothness and stability of the diffuser matrix mechanism 3. Compared to the original free-flowing gas penetration, the directional guidance and delivery of the diffuser matrix mechanism 3 ensures more comprehensive contact between the catalytic reaction zone and the isobutane gas flow, blocking the shortcut for gas escape and forcing the gas to pass evenly through the deep central bed, thereby achieving full-section velocity balance.

[0031] like Figure 4 As shown, preferably, the inner diameter of each guide pipe 6 is configured to be negatively correlated with the thickness of the catalyst bed corresponding to its location. Along the radial direction of the cross-section of the reactor 1, the inner diameters of the multiple guide pipes 6 are set in a gradient decreasing from the core material area to the edge material area.

[0032] In this embodiment, by configuring the inner diameter of the guide pipe 6 to be negatively correlated with the thickness of the catalyst bed above, the guide pipe 6 with the largest inner diameter is arranged in the central core material area (where the catalyst is thickest and the physical resistance of the medium is greatest) to provide the lowest inlet throttling resistance; while extending radially to both sides, as the catalyst bed gradually becomes shallower (the physical resistance of the medium decreases), the inner diameter of the guide pipe 6 decreases in a gradient stepwise, thereby artificially applying a sharply increased mechanical throttling resistance. Through this non-uniform geometric distribution of the pipe diameter, a high pressure drop barrier is pre-constructed in the edge area before the airflow officially enters the catalyst bed, so that the sum of the mechanical resistance of the guide pipe 6 and the corresponding catalyst bed resistance tends to a constant safety constant range across the entire cross-section of the reactor 1. The change in the inner diameter of the guide tube 6 forcibly blocks the shortcut for gas flow to escape to the edge, forcing the isobutane gas flow to penetrate the entire catalyst bed at a uniform flow rate, achieving the equilibrium of the flow field across the entire cross section, activating the originally idle central thick layer catalyst, ensuring that the reactants have a uniform residence time (equal space velocity) in the catalyst layer in different locations, effectively eliminating hot spot aggregation and coking caused by excessively high local flow rates in the edge region, while ensuring that all isobutane molecules can fully contact the active sites, thus improving the single-pass conversion rate of isobutene.

[0033] like Figure 6 As shown, preferably, the blocking structure 9 includes a fixing ring 10 embedded in the inner periphery of the guide hole 8. The inner ring of the fixing ring 10 is axially slidably connected to a sliding frame 11. A connecting rod 12 extends from the back of the sliding frame 11. An auxiliary spring 13 providing axial preload is sleeved on the outer periphery of the connecting rod 12. The distal end of the auxiliary spring 13 is limited by a limiting frame 14 fixed to the end of the connecting rod 12. Multiple venting grooves are evenly opened on the sliding frame 11 along the circumference, and each venting groove is covered with a venting mesh 15 for blocking catalyst fragments.

[0034] In this embodiment, during gas delivery, the gas is guided along the guide pipe 6 to the guide hole 8, and then blown towards the sliding frame 11. At this time, the sliding frame 11 is still inside the inner wall of the guide pipe 6. As the gas pushes the sliding frame 11, the auxiliary spring 13 is compressed in conjunction with the connecting rod 12 and the limiting frame 14. The sliding frame 11 then slides to the outside of the guide pipe 6. Subsequently, the gas flows to the catalytic reaction zone through the permeable mesh 15 on the sliding frame 11. Through this multi-point, multi-dimensional gas delivery method, the interaction between the gas and the catalytic reaction zone is further enhanced. The increased contact area between the components increases reaction efficiency, and the sliding of the sliding frame 11 is a floating process driven by gas. This causes the cap 7 to vibrate during the sliding process, thereby preventing the catalyst from accumulating on the breathable mesh 15 and the mechanical misalignment caused by friction between it and the inner wall of the fixing ring 10. It can directly generate microscopic shear stress. The vibration can tear and peel off the rigid coke and dust shells attached and hardened on the surface of the breathable mesh 15. The peeled material is then blown into the reaction zone by high-speed airflow, eliminating the tedious steps of stopping production to open the tank and manually disassembling and cleaning.

[0035] Example 3 like Figure 7 As shown, based on Embodiment 1, the present invention provides a technical solution: Preferably, the cross-zone thermal balance mechanism 4 includes two main pipes 16 symmetrically arranged above the partition plate 5. The two main pipes 16 form a medium interaction loop through a connecting conduit. Each main pipe 16 has several branch pipes 17 equidistantly distributed along the axial direction on its sidewall. Each branch pipe 17 is connected to a micro-network 18 for three-dimensional heat exchange deep inside the catalyst bed at one end away from its main pipe 16.

[0036] In this embodiment, isobutane dehydrogenation is a typical strongly endothermic reaction. When the DCS system described above performs low-load variable-domain operation and forces the material to converge in the core area, the catalyst in that area will experience severe local temperature drop (cold spots) due to intense endothermic reaction, while the edge material area retains a large amount of unused high-temperature sensible heat. When the edge zone acts as a "heat source" and the core zone acts as a "cold source," the micro-pipe network 18 in the edge zone instantly absorbs the sensible heat of the catalyst particles due to its large contact area. After being heated, the medium flows into the main stream pipe 16 through the corresponding branch pipe 17 and then flows at high speed across the zone to the core zone. Subsequently, the medium carrying a large amount of latent heat is then injected into the micro-pipe network 18 in the core zone through the branch pipes. This ensures that the catalytic reaction zone always operates at a high temperature. The micro-pipe network 18 allows for rapid heat exchange in three dimensions, which increases the heat exchange area and accelerates the heat exchange rate, thereby achieving better thermal balance and ensuring that the catalyst in the entire active reaction zone is always maintained within the optimal dehydrogenation thermodynamic temperature window. This ensures an extremely high single-pass conversion rate of isobutylene even under low load conditions. At the same time, this dispersed, mesh-like flexible end structure can effectively absorb and resolve the huge thermal stress generated by the system in frequent thermal cycles, preventing the components from breaking or deforming.

[0037] like Figure 7 As shown, preferably, the inner cavity of the cross-zone thermal balance mechanism 4 is sealed with a phase change heat transfer medium with high thermal conductivity.

[0038] In this embodiment, the phase change heat transfer medium can uniformly and quickly disperse and guide heat, thereby enabling the high-temperature zone and the low-temperature zone to quickly reach equilibrium, thus maintaining the efficient operation of the device.

[0039] like Figure 7 As shown, preferably, the cross-zone thermal balancing mechanism 4 also includes a support frame fixed above the partition plate 5. The top of the support frame is fixedly connected to the cross-zone thermal balancing mechanism 4. The cross-section of the main pipe 16 is arranged in a streamlined teardrop shape, and the rounded end of the teardrop-shaped cross-section faces the air intake direction of the feed hopper.

[0040] In this embodiment, the cross-section of the main pipe 16 is designed as a streamlined teardrop shape, and its rounded end is clearly defined to face downwards "facing the wind" and its sharp end to face upwards "away from the wind". When the high-speed airflow at the bottom surges in, the rounded lower edge can smoothly cut the airflow like the leading edge of an airfoil, minimizing shape drag. As the airflow climbs along the pipe wall, the sharp upper edge can gently guide the airflow on both sides to converge and close again, so that the airflow proceeds stably. The introduction of the support frame changes the stress state of the main pipe being suspended at both ends. It anchors the base to the solid partition plate 5 below, and like a bridge pier, it vertically and evenly transmits and unloads the main pipe 16's own weight, working fluid load, and fluid impact force to the reactor's foundation load-bearing components. At the same time, the connection of the support frame reserves sliding freedom for the linear thermal expansion of the pipe body.

[0041] The present invention also provides a dehydrogenation system, comprising: S1, Load sensing and dynamic zoning stage; Load monitoring: The system collects the total flow rate of the raw material isobutane in real time through sensors installed on feed channel 2. ; Threshold determination: The multi-target variable domain allocation unit in the DCS calls the global evaluation model. When the calculated global average airspeed falls below the anti-focus airspeed safety threshold, the threshold is determined. At that time, the system determined that the system had entered the "coking risk zone"; Variable Domain Command: The system generates a variable domain allocation command, which drives the flow control valve assembly to perform actions. By closing or reducing the branch pipes in the edge material zone, the raw material gas is forced to converge into the core material zone, artificially reducing the volume of the active catalyst. This allows the local apparent airspeed to return to a safe range; S2, pressure drop compensation and precision gas distribution stage and radial dispersion and catalytic reaction stage; The gas flows to the diffuser matrix 3, which performs gradient resistance compensation. S3, the stage of cross-regional thermal balance and energy replenishment; Temperature difference sensing and latent heat transport, through the setting of the cross-zone thermal balance mechanism 4, maintain the temperature difference balance between the core area (cold end) and the edge material area (hot end).

[0042] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. An isobutane dehydrogenation device, comprising: Reactor (1), the reactor (1) is a horizontal cylindrical structure, the inner cavity of which is divided into an upper catalytic reaction zone and a lower feed hopper; A feed channel (2) is fixedly installed on the side wall of the reactor (1). The feed channel (2) includes at least two feed branch pipes that are independently connected to the inside of the reactor (1). Each feed branch pipe is equipped with a flow control valve group. The feed channel (2) is characterized by further including: The diffuser matrix mechanism (3) is fixedly installed inside the reactor (1) to diffuse the gas flow entering the reactor (1) radially into the catalyst after being dispersed and compensated by the diffuser matrix mechanism (3); A cross-regional thermal balancing mechanism (4), installed above the diffuser matrix mechanism (3) and spanning different reaction sites of the catalytic reaction zone, is used to balance the heat transfer of different regions during the dehydrogenation reaction; and The DCS control system is communicatively connected to each of the flow control valve groups. The DCS control system is equipped with a multi-objective variable domain allocation unit. The multi-objective variable domain allocation unit is configured to: based on the acquired feed load and bed temperature data, call a global evaluation model that includes a weighted item for the full bed conversion rate and a penalty item for local coking risk, and generate a variable domain allocation command to drive the flow control valve groups to act independently. The feed hopper includes a core material zone located in the middle of the reactor cross-section and edge material zones located on both sides of the core material zone. At least two feed branch pipes are respectively connected to the core material zone and the edge material zone. The construction logic of the global evaluation model is as follows: Set a safe airspeed threshold for anti-fogging; When the expected value of the local apparent space velocity calculated under the uniform feeding of the whole domain is greater than the anti-coking space velocity safety threshold, the weight of the local coking risk penalty term approaches zero, and the variable domain allocation instruction aims to balance the feeding of the whole domain and maximize the weight of the whole bed conversion rate. When the expected value of the local apparent space velocity calculated under the uniform feeding of the whole domain is less than the anti-coking space velocity safety threshold, the weight of the local coking risk penalty term increases sharply in a non-linear manner, and the variable domain allocation instruction is forced to prioritize increasing the local apparent space velocity of the core material area. By reducing the opening of the flow control valve group of the edge material area, the feed airflow is forced to converge to the core area.

2. The isobutane dehydrogenation apparatus according to claim 1, characterized in that: The diffuser matrix mechanism (3) includes a partition plate (5) fixed laterally in the inner cavity of the reactor (1), and a number of longitudinally extending guide pipes (6) are distributed in a staggered array on the partition plate (5); the top of each guide pipe (6) is fixed with a cap (7) for blocking vertical airflow, and a number of radial diffuser holes (8) are equidistantly and staggered along the axial direction on its circumferential outer wall surface, and a blocking structure (9) for intercepting catalyst particles is fixed inside the guide hole (8).

3. The isobutane dehydrogenation apparatus according to claim 2, characterized in that: The inner diameter of each of the guide pipes (6) is configured to be negatively correlated with the thickness of the catalyst bed corresponding to its location. Along the radial direction of the cross-section of the reactor (1), the inner diameters of the multiple guide pipes (6) are set in a gradient decreasing from the core material area to the edge material area.

4. The isobutane dehydrogenation apparatus according to claim 3, characterized in that: The blocking structure (9) includes a fixing ring (10) embedded in the inner periphery of the guide hole (8). The inner ring of the fixing ring (10) is axially slidably connected to a sliding frame (11). A connecting rod (12) extends from the back of the sliding frame (11). An auxiliary spring (13) providing axial preload is sleeved on the outer periphery of the connecting rod (12). The distal end of the auxiliary spring (13) is limited by a limiting frame (14) fixed to the end of the connecting rod (12). Multiple air vents are evenly opened on the sliding frame (11) along the circumference, and each air vent is covered with an air vent mesh (15) for blocking catalyst fragments.

5. The isobutane dehydrogenation apparatus according to claim 4, characterized in that: The cross-zone thermal balance mechanism (4) includes two main pipes (16) symmetrically arranged above the partition plate (5). The two main pipes (16) form a medium interaction loop through a connecting conduit. Each main pipe (16) has several branch pipes (17) equidistantly distributed along the axial direction on its sidewall. Each branch pipe (17) is connected to a micro-network (18) for three-dimensional heat exchange deep inside the catalyst bed at one end away from its main pipe (16).

6. The isobutane dehydrogenation apparatus according to claim 5, characterized in that: The inner cavity of the cross-regional thermal balance mechanism (4) is sealed with a phase change heat transfer medium with high thermal conductivity.

7. An isobutane dehydrogenation apparatus according to claim 6, characterized in that: The cross-zone thermal balancing mechanism (4) also includes a support frame fixed above the partition plate (5). The top of the support frame is fixedly connected to the cross-zone thermal balancing mechanism (4). The cross-section of the main pipe (16) is arranged in a streamlined teardrop shape, and the rounded end of the teardrop-shaped cross-section faces the air intake direction of the feed hopper.

8. A dehydrogenation system, applicable to the isobutane dehydrogenation apparatus according to any one of claims 1-7, characterized in that, include: S1, Load sensing and dynamic zoning stage; Load monitoring: The system collects the total flow rate of the raw material isobutane in real time through sensors installed on the feed channel (2). ; Threshold determination: The multi-target variable domain allocation unit in the DCS calls the global evaluation model. When the calculated global average airspeed falls below the anti-focus airspeed safety threshold, the threshold is determined. At that time, the system determined that the system had entered the "coking risk zone"; Variable Domain Command: The system generates a variable domain allocation command, which drives the flow control valve assembly to perform actions. By closing or reducing the branch pipes in the edge material zone, the raw material gas is forced to converge into the core material zone, artificially reducing the volume of the active catalyst. This allows the local apparent airspeed to return to a safe range; S2, pressure drop compensation and precision gas distribution stage and radial dispersion and catalytic reaction stage; The gas flows to the diffuser matrix mechanism (3), and the gradient resistance compensation is completed by the diffuser matrix mechanism (3); S3, the stage of cross-regional thermal balance and energy replenishment; Temperature difference sensing and latent heat transport, through the setting of cross-zone thermal balance mechanism (4), maintain the temperature difference balance between the core area (cold end) and the edge material area (hot end).

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