Partitioned annular electric heat tracing radial propane dehydrogenation reactor and heating method thereof

Abstract

The invention relates to the technical field of reactors, in particular to a partition annular electric heat tracing radial propane dehydrogenation reactor and a heating method thereof.The partition annular electric heat tracing radial propane dehydrogenation reactor comprises a reactor shell, a reaction cavity is formed in the reactor shell, and a heat preservation layer is arranged in an interlayer in the reactor shell; the radial bed layer structure is arranged in the reaction cavity and comprises an inner cylinder and an outer cylinder which are concentrically arranged, as well as a catalyst bed layer and an electric heat tracing system which are filled between the inner cylinder and the outer cylinder, and the electric heat tracing system comprises a plurality of electric heat tracing assemblies and a power supply module; the temperature control system comprises temperature sensors arranged in the annular heating areas in a distributed mode and a controller. Compared with the prior art, the electric heat tracing assembly is directly buried in the catalyst bed layer, energy is supplied to all the areas through the independent power supply branch circuits, power is independently adjusted through the controller, partition differentiation heat compensation can be implemented according to the difference that heat dissipation of the outer ring is higher and heat absorption of the inner ring is higher, and the radial temperature difference and local temperature fluctuation of the bed layer are remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of reactor technology, in particular to a partitioned annular electrically heated radial propane dehydrogenation reactor and a heating method thereof. BACKGROUND

[0002] Propane dehydrogenation (PDH) is one of the key process routes for producing propylene from propane. The reaction is a strong endothermic gas-solid catalytic reaction, and a large amount of heat needs to be continuously input to maintain a high-temperature reaction zone. The matching of the temperature field and heat supply during the reaction directly affects the equilibrium conversion rate, selectivity, and catalyst life. Literature and engineering design data generally point out that the dehydrogenation reactor operates under high temperature, complex load, and frequent temperature change conditions, and the equipment structure and heat management are difficult. Temperature difference stress and heat transfer efficiency are one of the key points in design.

[0003] In the prior art, in terms of fixed bed reactors, a kind of axial-radial fixed bed reactor for propane dehydrogenation with patent number CN112473568A, typical structure includes inner cylinder, outer cylinder and annularly arranged catalyst bed, raw materials pass through catalyst bed in radial mode between inner and outer cylinder for dehydrogenation reaction, such axial / radial flow structure is beneficial to increase flow area, reduce superficial gas velocity and improve pressure drop;In terms of bed heat supply / temperature equalization scheme, a method and device for improving fixed bed dehydrogenation conversion efficiency with patent number CN113149802A propose to realize reaction process heat balance and temperature balance in fixed bed dehydrogenation conversion by various heat supply means (such as bed built-in heating pipe, different heat medium coupling, alternating reaction-regeneration heat storage heat supply, etc.), and emphasize that heat is introduced by heat coupling and heating pipe to improve bed temperature distribution;Consistent with traditional method, in strong endothermic dehydrogenation reaction, bed internal reaction rate and heat dissipation condition are often inconsistent in radial / circumferential direction, superimposed shell heat dissipation and flow distribution deviation, local hot spots or cold spots are easily formed;Hot spots will exacerbate catalyst sintering, coking and side reactions, cold spots will cause conversion rate to decrease and temperature field fluctuation to expand, resulting in yield and running stability to be affected, and existing dehydrogenation device often relies on external heat supply or indirect heat supply means to compensate for heat absorption, temperature field adjustment usually has response lag, steady-state deviation is difficult to eliminate or control coupling is complex, etc. Phenomenon;When feed quantity, raw material concentration or environmental heat dissipation changes, bed temperature is prone to overshoot / oscillation, resulting in energy consumption rising and heat shock increasing, thereby affecting catalyst life and device economy, in addition, dehydrogenation reaction runs in high temperature zone, temperature anomaly (overtemperature or low temperature) is sensitive to catalyst and equipment safety boundary;Once local heat supply is out of control, temperature drift or working condition disturbance amplification occurs, if reliable interlocking and partition isolation strategy is lacked, local overheating damage, unstable operation or even forced overall shutdown are easily caused, thereby reducing long-period operation ability of device, therefore, the present application discloses a partition annular electric heat tracing radial propane dehydrogenation reactor and heating method thereof. SUMMARY

[0004] Therefore, the present application discloses a partition annular electric heat tracing radial propane dehydrogenation reactor and heating method thereof to solve the problems of uneven bed temperature, temperature adjustment response lag and easy fluctuation, insufficient safety interlocking and continuous operation ability when temperature anomaly exists in existing propane dehydrogenation reactor.

[0005] Based on the above purpose, the present application provides a partition annular electric heat tracing radial propane dehydrogenation reactor, which comprises: a reactor shell, a reaction cavity is formed in the reactor shell, and a heat preservation layer is arranged in the interlayer of the reactor shell; A radial bed structure is arranged in the reaction cavity, comprising concentrically arranged inner and outer cylinders and a catalyst bed filled between the inner and outer cylinders, and a plurality of groups of flow-through holes are arranged on the cylinder walls of the inner and outer cylinders to enable the reaction medium to flow radially through the catalyst bed; An electric heat tracing system comprises a plurality of electric heat tracing assemblies and a power supply module, the electric heat tracing assemblies are directly embedded inside the catalyst bed and divide the catalyst bed into at least two independent concentric annular heating zones along the radial direction of the reactor shell, and the electric heat tracing assemblies in each annular heating zone are connected to an independent power supply branch of the power supply module; A temperature control system comprises temperature sensors distributed in each annular heating zone and a controller electrically connected to each temperature sensor and each power supply branch, for independently adjusting the heating power of the corresponding annular heating zone according to the independent temperature monitoring data of each annular heating zone.

[0006] Preferably, the electric heat tracing assemblies are further divided into at least two axial heating sections along the axial direction of the reactor shell, and each axial heating section is respectively provided with an independent power supply branch, and the controller is used to independently adjust the heating power of different axial heating sections.

[0007] Preferably, the electric heat tracing assemblies are at least one of an electric heating rod, a flexible electric heat tracing tape or an electric heating plate; wherein the surface of the electric heating rod is provided with fins or heat transfer nails to increase the heat transfer area, and the material of the electric heating plate is silicon carbide or graphene composite heating material.

[0008] Preferably, the division of the annular heating zones is designed according to the radial heat load distribution of the catalyst bed 8, and the ratio of the design heating power of the outer annular heating zone to the inner annular heating zone satisfies the following relationship: wherein, and are the design heating powers of the outer annular heating zone and the inner annular heating zone, respectively, and are the equivalent radii of the outer annular heating zone and the inner annular heating zone, respectively, is a heat loss compensation coefficient, and the value range is 1.0-1.5.

[0009] Preferably, the temperature control system further comprises an alarm module; the controller is configured to trigger the alarm module and perform a safety interlock action of reducing the heating power or cutting off the power supply of the zone when the monitored temperature of any annular heating zone continuously exceeds a preset safety threshold range; the upper limit of the safety threshold range is 630℃, and the lower limit is 590℃.

[0010] Preferably, the inner cylinder and the outer cylinder are Johnson mesh structures with slit widths less than 2 mm; the upper part of the radial bed structure is provided with a raw material distribution pipe, the side wall of the raw material distribution pipe is provided with a plurality of distribution holes, the diameter of the distribution holes is 3 mm, and the opening rate of the raw material distribution pipe is 20%.

[0011] Preferably, the insulation layer is made of aluminum silicate cotton or rock wool, and its thickness is 50–200 mm.

[0012] This invention also discloses a heating method for a partitioned annular electrically heated radial propane dehydrogenation reactor, which, when used in the aforementioned partitioned annular electrically heated radial propane dehydrogenation reactor, includes the following steps: S1: Start the electric heat tracing system to heat the catalyst bed 8 through the electric heat tracing components of each annular heating zone; S2: Temperature data of each zone is collected in real time through temperature sensors distributed within each annular heating zone. ,in The numbering of the annular heating zone; S3: The controller will collect temperature data from each zone. and their respective preset target temperatures Compare and calculate real-time temperature difference , Based on a preset collaborative control algorithm, it independently calculates and outputs power regulation signals for each power supply branch; S4: Based on the power adjustment signal, independently adjust the real-time heating power of each annular heating zone. To adjust the temperature of each zone Stabilize at the target temperature This ensures a uniform radial temperature distribution within the catalyst bed 8, thus achieving a uniform distribution of temperature in the vicinity. Wherein, the target temperature The value ranges from 590℃ to 630℃.

[0013] Preferably, the cooperative control algorithm described in step S3 is a composite control algorithm combining feedforward and feedback, specifically as follows: The controller is based on the formula Calculate the first Heating power of the zone; in, The numbering of the annular heating zone; For the first Real-time heating power of each annular heating zone; For the first The basic power setting value for each annular heating zone; and These are the proportional and integral coefficients of the controller, respectively. For real-time temperature difference; When the annular heating zone includes an outer annular heating zone and an inner annular heating zone, the outer annular heating zone has a larger equivalent radius, and the inner annular heating zone has a smaller equivalent radius. The base power settings for the outer annular heating zone and the inner annular heating zone are respectively denoted as... and And satisfy the following relationship: , in, and These are the equivalent radii of the outer and inner annular heating zones, respectively, where the equivalent radius is the arithmetic mean of the radial inner boundary radius and the radial outer boundary radius of the corresponding annular heating zone. This is the radial heat loss compensation coefficient, with a value ranging from 1.0 to 1.5.

[0014] Preferably, the process further includes an optimization step: dynamically adjusting the set value of the base power Pbase,i based on changes in the reactor feed flow rate or raw material concentration; and, when a certain annular heating zone is cut off from power due to a fault, correspondingly increasing the target temperature Tset,j (j≠i) of its adjacent annular heating zones to maintain the overall reactor processing efficiency, and the increased target temperature Tset,j does not exceed 630℃. The beneficial effects of this invention are: This type of partitioned annular electrically heated radial propane dehydrogenation reactor and its heating method directly embeds the electrically heated components inside the catalyst bed and divides the reactor radially into at least two independent concentric annular heating zones. Each zone is powered by an independent power supply branch and its power is independently adjusted by a controller. This allows for "zonal differentiated heating" to address the difference between the stronger heat dissipation of the outer ring and the stronger heat absorption of the inner ring. This significantly reduces the radial temperature difference and local temperature fluctuations in the bed, minimizing catalyst sintering deactivation caused by hot spots and conversion loss caused by cold spots. At the same time, the radial bed structure, combined with the uniform feed distribution pipe, reduces local high reaction rates and temperature disturbances caused by biased flow, making the reaction closer to plug flow and the temperature field more uniform. This improves propylene selectivity and yield stability and extends catalyst life.

[0015] Distributed temperature sensors are used to collect temperature data in real time for each annular heating zone and adjust the power of each zone in a closed loop. This achieves an independent control link of "zoned heating - zoned temperature measurement - zoned power adjustment," which avoids control lag and missed hot spots caused by single-point temperature measurement. This allows the bed to quickly return to the target temperature zone even when the feed rate, raw material concentration, or environmental heat dissipation changes. Furthermore, by combining a feedforward + feedback composite power adjustment approach (using the base power to cover the average heat load and using the proportional / integral term to correct for disturbance deviations), overshoot and oscillation caused by relying solely on feedback can be reduced, as well as thermal shock and ineffective energy consumption caused by frequent large-scale power adjustments. This makes the 590–630℃ target temperature zone more stable, thereby reducing the energy consumption per unit product while ensuring conversion rate and selectivity.

[0016] The temperature control system incorporates an alarm module that triggers an alarm and implements interlocking protection by reducing power or cutting off the power supply to any annular heating zone when the temperature continuously exceeds the safety threshold. This gives the system clear "hard boundary" safety control: on the one hand, it suppresses the risk of catalyst sintering, coking side reactions, and thermal stress on equipment caused by overheating; on the other hand, it promptly alarms and takes protective measures when the temperature is low or the power supply is abnormal, avoiding the expansion of fluctuations due to malfunctions. At the same time, the structure of independent power supply in zones naturally supports "fault zone isolation rather than system-wide shutdown". Combined with adjacent zone compensation and control strategies, it can significantly reduce the probability of unplanned shutdowns and improve the long-term stable operation capability and economy of the unit. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a top view of the structure of the present invention; Figure 3 This is a schematic diagram of the overall structure and partitions of the reactor of the present invention; Figure 4 This is a block diagram of the power supply for the electric heat tracing system of the present invention. Figure 5 This is a schematic diagram of the closed-loop control principle of the temperature control system of the present invention; Figure 6 This is a flowchart of the heating method control of the present invention; Figure 7 This is a schematic diagram of the collaborative control algorithm of the present invention.

[0019] The diagram is marked as follows: 1. Reactor shell; 2. Insulation layer; 3. Reaction chamber; 4. Radial bed structure; 5. Inner cylinder; 6. Outer cylinder; 7. Flow hole; 8. Catalyst bed. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0021] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] like Figures 1 to 7As shown, the partitioned annular electrically heated radial propane dehydrogenation reactor includes a reactor shell 1, with a reaction chamber 3 formed inside the reactor shell 1. An insulation layer 2 is provided in the internal interlayer of the reactor shell 1. A radial bed structure 4 is disposed within the reaction chamber 3, including concentrically arranged inner cylinders 5 and outer cylinders 6, and a catalyst bed 8 filled between the inner and outer cylinders 5 and 6. Multiple sets of flow holes 7 are provided on the walls of both the inner and outer cylinders 5 and 6 to allow the reaction medium to flow radially through the catalyst bed 8. An electric heating system includes several electric heating components and a power supply module. The electric heating components are directly embedded inside the catalyst bed 8 and divide the catalyst bed 8 into at least two independent concentric annular heating systems along the radial direction of the reactor shell 1. The heating zone, with each annular heating zone having an electric heat tracing component connected to an independent power supply branch of the power supply module; the temperature control system, including temperature sensors distributed in each annular heating zone and a controller, the controller being electrically connected to each temperature sensor and each power supply branch, used to independently adjust the heating power of the corresponding annular heating zone based on the independent temperature monitoring data of each annular heating zone; the inner cylinder 5 and the outer cylinder 6 are Johnson mesh structures with slit widths less than 2mm; the upper part of the radial bed structure 4 is provided with a raw material distribution pipe, the side wall of which has several distribution holes with a diameter of 3mm and an opening rate of 20%; the insulation layer 2 is made of aluminum silicate cotton or rock wool with a thickness of 50–200mm; The reactor shell 1 forms a reaction chamber 3 inside to accommodate the radial bed structure 4 and provide a closed reaction space for the reaction medium. An insulation layer 2 (preferably aluminosilicate cotton or rock wool, 50–200 mm thick) is installed outside the reactor shell 1. Its function is to significantly reduce heat loss from the reaction chamber 3 to the environment, reduce thermal bridges and temperature fluctuations on the outer wall, and allow more of the heat provided by the electric heating to compensate for the strong endothermic demand of the propane dehydrogenation reaction, thereby reducing energy consumption per unit product and improving bed temperature stability. The radial bed structure 4 is located inside the reaction chamber 3 and includes concentrically arranged inner cylinders 5 and outer cylinders 6, with a catalyst bed 8 filling the space between them. Multiple sets of flow holes 7 are opened on the walls of the inner cylinders 5 and outer cylinders 6 to allow the reaction medium to pass through. The catalyst flows radially through the catalyst bed 8. This radial flow pattern, compared to axial flow, effectively reduces bed pressure drop and mitigates channeling phenomena, resulting in a more uniform distribution of reactants in both the circumferential and radial directions. Combined with electric heat tracing for zoned heating, this reduces local temperature differences within the bed, suppresses hot spots, and extends catalyst life. The inner cylinder 5 and outer cylinder 6 are preferably Johnson mesh structures with slit widths less than 2 mm. This ensures sufficient opening area while reliably trapping catalyst particles to prevent spillage. Furthermore, the uniform slits facilitate radial flow rectification, making the heating and reaction of the catalyst bed 8 more consistent. The electric heat tracing components of the electric heat tracing system are directly embedded inside the catalyst bed 8 and extend radially along the reactor shell 1. The catalyst bed 8 is divided into at least two independent concentric annular heating zones. The electric heating components within each annular heating zone are connected to an independent power supply branch of the power supply module. This allows for differentiated heating based on the heat dissipation and endothermic reaction intensities at different radial locations, avoiding underheating on the outer side or overheating on the inner side caused by single-loop heating, thus improving the uniformity of the radial temperature field and propylene selectivity. The temperature control system uses distributed temperature sensors within each annular heating zone to collect temperature data and transmit it to the controller. The controller is electrically connected to each power supply branch and independently adjusts the heating power of the corresponding annular heating zone based on the independent temperature monitoring data, ensuring that the catalyst bed 8 operates under conditions such as feed rate and raw material fluctuations. Even under changes in concentration and environmental heat dissipation, it can still quickly stabilize to the target temperature range, reducing the adverse effects of temperature overshoot and fluctuations on catalyst activity and equipment thermal shock. The upper part of the radial bed structure 4 is equipped with a raw material distribution pipe with several distribution holes on its side wall. The hole diameter is 3mm and the opening rate is 20%. This setting achieves circumferential uniform distribution of feed before entering the outer cylinder 6 through the orifice plate throttling and uniform distribution mechanism, reducing the local high reaction rate and temperature disturbance caused by local high flow rate injection. It improves the flow distribution of radial bed penetration from the source. Combined with zoned electric heating and zoned temperature measurement closed-loop control, it can further reduce the bed temperature difference and the risk of local overheating, thereby improving reaction stability, reducing coking tendency and improving the long-term operation capability of the unit.

[0023] like Figures 1 to 5As shown, the electric heat tracing assembly is further divided into at least two axial heating sections along the axial direction of the reactor shell 1. Each axial heating section is provided with an independent power supply branch. The controller is used to independently adjust the heating power of different axial heating sections. The electric heat tracing assembly is at least one of electric heating rod, flexible electric heating tape, or electric heating plate. The surface of the electric heating rod is provided with fins or heat transfer nails to increase the heat transfer area. The electric heating plate is made of silicon carbide or graphene composite heating material. Based on the aforementioned radial concentric annular partitioning, the electric heating assembly is further divided into at least two axial heating sections along the axial direction of the reactor shell 1. Each axial heating section is equipped with an independent power supply branch, and its heating power is independently adjusted by the controller. The purpose of this arrangement is that propane dehydrogenation typically exhibits differences in reaction rate and endothermic intensity along the bed height (e.g., the reaction is more vigorous and the temperature drop is more significant in the inlet section). If only radial partitioning is performed, axial temperature differences and local temperature fluctuations may still occur. However, axial partitioning allows for stronger supplemental heating of the inlet section and more precise temperature stabilization of the middle and later sections. This simultaneously suppresses the temperature gradient in the "radial × axial" two-dimensional space, improves the temperature uniformity of the entire bed and the stability of propylene yield, and reduces the thermal shock caused by frequent and large-scale power adjustments. The electric heating assembly can be selected from at least one of electric heating rods, flexible electric heating tapes, or electric heating plates. Among them, electric heating rods are preferably provided with fins or heat transfer nails on their surface to increase the heat exchange area with catalyst particles and enhance the local thermal conductivity / radiation heat transfer capacity, so that heat is more evenly diffused to the surrounding catalyst particles, reducing the "heat source near" area. The temperature difference phenomenon of "overheating and underheating away from the heat source" is eliminated, thereby reducing the risk of catalyst deactivation due to hot spots. When using electric heating plates, silicon carbide or graphene composite heating materials can be selected to obtain higher temperature resistance and more stable electrothermal conversion performance, which is suitable for long-term high-temperature operation. The specific implementation method is as follows: when filling the catalyst bed 8, the electric heating components corresponding to each axial heating section are inserted / laid inside the bed according to the predetermined circumferential spacing and height position, and fixed by high-temperature resistant insulating brackets and positioning components to prevent displacement caused by operating vibration. At the same time, the leads of each section are led out through sealed electrical penetration parts and connected to the corresponding branch of the power supply module. The controller outputs power adjustment signals based on the real-time temperature data of temperature sensors arranged in each axial section and each annular area to achieve coordinated heating and stable temperature control between different axial sections. Through the combination of the above structure and control, the radial and axial temperature consistency of the bed can be significantly improved while ensuring heating safety and reliability, reducing side reactions and coking caused by local overheating and temperature fluctuations, improving reactor operation stability and extending catalyst service life. To ensure that those skilled in the art can implement the in-bed electric heating structure, it is preferable to embed the electric heating components inside the catalyst bed 8 at predetermined circumferential spacing and axial height during catalyst loading, and fix them with high-temperature resistant insulating supports, positioning components, or sheath structures to prevent displacement, short circuits, or localized overheating of heating elements due to operating vibrations or catalyst settling. The leads for each heating zone are preferably led out through sealed electrical penetrations on the reactor shell 1, and employ high-temperature resistant insulating materials and grounding protection measures to meet electrical safety requirements under high-temperature hydrocarbon atmospheres. Furthermore, it is preferable to design the electric heating components as a modular, replaceable structure, allowing them to be pulled out from the top or side of the reactor for maintenance or catalyst replacement during shutdown, thereby improving the long-term operational reliability and engineering feasibility of the unit.

[0024] like Figures 1 to 5 As shown, the division of the annular heating zone is designed based on the radial heat load distribution of the catalyst bed 8. The ratio of the design heating power of the outer annular heating zone to that of the inner annular heating zone satisfies the following relationship: ,in, and The design heating power for the outer annular heating zone and the inner annular heating zone are respectively. and These are the equivalent radii of the outer and inner annular heating zones, respectively. This is the heat loss compensation coefficient, with a value ranging from 1.0 to 1.5; Specifically, the division of the annular heating zone is designed based on the radial heat load distribution of the catalyst bed 8. The core idea is to distribute and compensate for the "reaction endothermic demand + outward heat loss" at different equivalent radius positions of the catalyst bed 8, thereby avoiding underheating on the outer side or overheating on the inner side caused by uniform heating in a single area. In actual operation, the outer ring area near the reactor shell 1 is more susceptible to radial heat loss due to the temperature difference between the shell and the environment, and a lower outer temperature can cause a decrease in local conversion rate and increased temperature fluctuations. Therefore, this embodiment satisfies the requirement that the ratio of the designed heating power of the outer annular heating zone to the inner annular heating zone be preset to meet the specified requirements. The relationship allows the outer ring area to have a higher heating capacity in terms of basic heating supplementation, among which... and These represent the design heating power for the outer ring area and the inner ring area, respectively. and The equivalent radius corresponds to the annular heating zone. In engineering, the equivalent radius can be determined by the radial inner boundary radius of each annular zone. Radial outer boundary radius The arithmetic mean is determined, that is This allows the outer ring region with a larger radius to obtain a basic power configuration that matches its radial heat loss; heat loss compensation coefficient The value used to characterize the additional heat dissipation compensation intensity of the outer ring region relative to the inner ring region ranges from 1.0 to 1.5. During implementation, it can be calibrated based on the thickness of the insulation layer 2, ambient temperature, outer surface temperature of the shell, and temperature deviation during the initial stage of operation. For example, a lower value (close to 1.0) is used when the insulation is good, the ambient temperature is high, and the heat dissipation from the outer wall is small; a higher value (close to 1.5) is used when the ambient temperature is low, or the heat dissipation from the outer wall is large, and the temperature drop in the outer ring region is more significant. Specifically, the catalyst bed 8 is first divided into at least two concentric annular heating zones based on its radial thickness, and the boundary radius of each annular zone is determined. The calculated value is then obtained... and Then, according to the above relationship, the basic design power ratio of each ring zone is given and the number or rated power of electric heating components is allocated to make the outer ring zone have higher basic heating redundancy. Finally, the power of each zone is finely adjusted under the closed-loop regulation of the temperature control system to offset the disturbance caused by fluctuations in feed rate, raw material composition and reaction intensity. Through the combination strategy of "basic power allocation based on heat loss compensation + zoned closed-loop fine adjustment", the radial temperature difference of catalyst bed 8 can be significantly reduced, the risk of insufficient reaction caused by local temperature trough and catalyst sintering deactivation caused by local hot spots can be reduced, thereby improving propylene selectivity and yield stability, and reducing energy consumption and thermal shock of electric heating elements caused by frequent large-scale power adjustment. The temperature control system also includes an alarm module; the controller is configured to trigger the alarm module and execute a safety interlock action of reducing the heating power of the zone or cutting off the power supply to the zone when the monitored temperature of any annular heating zone continuously exceeds the preset safety threshold range; the upper limit of the safety threshold range is 630℃ and the lower limit is 590℃. The temperature control system is equipped with an alarm module, and the controller performs a safety interlock action of reducing power or cutting off power supply when the temperature in any annular heating zone continuously exceeds the preset safety threshold range. Its function is to provide a clear "hard protection boundary" for zoned electric heating, preventing irreversible overheating damage to the catalyst bed 8 or reaction instability caused by excessively low temperatures due to abnormal electric heating elements, power supply module malfunction, thermocouple drift, feed fluctuations, or local reaction anomalies. In this embodiment, the upper limit of the safety threshold is set at 630℃ and the lower limit at 590℃. When the monitored temperature exceeds 630℃... At ℃, local hot spots may appear in the bed, accelerating catalyst sintering, coking, or increasing side reactions. This also negatively impacts the thermal stress on the inner and outer cylinders and the shell. Therefore, the controller prioritizes rapid power reduction. If the temperature continues to rise or exceeds the set sustained threshold, the corresponding power supply branch is immediately cut off, triggering an audible and visual alarm to achieve graded protection of "suppression first, then isolation." When the monitored temperature is below 590℃, the bed may experience a decrease in reaction rate, a decline in conversion rate, and increased temperature fluctuations. The controller can first increase the power in this area to compensate. If the low temperature persists, it indicates a power supply failure. If the heat source fails, an alarm will be triggered and corresponding protection strategies will be implemented (e.g., disconnecting the faulty branch and prompting for maintenance) to avoid greater fluctuations caused by operating with defects. The specific implementation method is as follows: at least one temperature sensor is arranged in each annular heating zone and its signal is connected to the controller. The controller collects and filters the temperature at a fixed sampling period (e.g., moving average or multi-point consistency check to eliminate instantaneous spikes), sets a "continuous over-limit" criterion (e.g., multiple consecutive samplings exceeding the limit or the over-limit lasting for a preset time) to avoid false alarms, and then implements the corresponding interlock strategy for the over-limit area: when the temperature is too high, the power in that area is reduced by a set slope and the power supply branch is disconnected if necessary; when the temperature is too low, the power is increased and the power supply is disconnected and an alarm is triggered when a fault is detected. At the same time, the event and temperature curve are recorded for traceability. Through this alarm interlock mechanism, the system safety and reliability can be significantly improved while ensuring that the reaction temperature zone is controllable, reducing the shortening of catalyst life and equipment damage caused by local overheating, reducing the probability of unplanned shutdowns, and achieving "fault zone isolation rather than full system shutdown" in conjunction with the structure of independent power supply in zones, thereby improving the long-term stable operation capability and economy of the device.

[0025] like Figures 1 to 7 As shown, a heating method for a partitioned annular electrically heated radial propane dehydrogenation reactor, applied to the aforementioned partitioned annular electrically heated radial propane dehydrogenation reactor, includes the following steps: S1: Start the electric heat tracing system to heat the catalyst bed 8 through the electric heat tracing components in each annular heating zone; S2: Temperature data of each zone is collected in real time through temperature sensors distributed within each annular heating zone. ,in The numbering of the annular heating zone; S3: The controller will collect temperature data from each zone. and their respective preset target temperatures Compare and calculate real-time temperature difference , Based on a preset collaborative control algorithm, it independently calculates and outputs power regulation signals for each power supply branch; S4: Independently adjust the real-time heating power of each annular heating zone according to the power adjustment signal. To adjust the temperature of each zone Stabilize at the target temperature This ensures a uniform radial temperature distribution within the catalyst bed 8, thus achieving a uniform distribution of temperature in the vicinity. Among them, target temperature The value ranges from 590℃ to 630℃; Specifically, the rapid heating and steady-state temperature control of catalyst bed 8 are achieved through a closed-loop process of "zoned heating - zoned temperature measurement - zoned power adjustment": In step S1, the electric heating system is activated, so that the electric heating components embedded in the catalyst bed 8 in each annular heating zone are energized and heated, thereby providing in-situ heating to the catalyst bed 8 to counteract the strong endothermic effect of the propane dehydrogenation reaction. In step S2, temperature sensors distributed within each annular heating zone (and, if necessary, at different radial positions inside / in the middle / outside the bed) are used to collect temperature data of each zone in real time. This zoned temperature measurement can create a real-time "portrait" of the radial temperature distribution of the bed, avoiding control lag or missed detection of local hot spots caused by relying solely on single-point temperature measurement; In step S3, the controller will With the corresponding target temperature Compare and calculate real-time temperature differences Then, the power adjustment signals of each power supply branch are output independently, so that the adjustment of different annular heating zones is not coupled or interfered with each other, thus allowing for differentiated heating based on differences such as greater heat dissipation in the outer ring zone and stronger heat absorption in the inner ring zone. In step S4, the real-time heating power of each zone is adjusted according to the power adjustment signal. Independent adjustments are made to ensure the temperature in each zone is controlled. Stable at the corresponding This allows for a uniform distribution of radial temperature in the catalyst bed 8, thereby reducing the risk of side reactions, coking, and catalyst deactivation caused by temperature fluctuations. in The value is limited to the range of 590℃ to 630℃. On the one hand, it covers the effective temperature range of propane dehydrogenation reaction to ensure conversion rate and selectivity. On the other hand, it is coordinated with the safety threshold to avoid overheating damage, thereby improving the stability of propylene yield while reducing energy consumption and the probability of unplanned shutdowns.

[0026] The cooperative control algorithm in step S3 is a composite control algorithm that combines feedforward and feedback, specifically as follows: The controller is based on the formula Calculate the first Heating power of the zone; in, The numbering of the annular heating zone; For the first Real-time heating power of each annular heating zone; For the first The basic power setting value for each annular heating zone; and These are the proportional and integral coefficients of the controller, respectively. For real-time temperature difference; When the annular heating zone includes an outer annular heating zone and an inner annular heating zone, the outer annular heating zone has a larger equivalent radius, and the inner annular heating zone has a smaller equivalent radius. The base power settings for the outer and inner annular heating zones are denoted as follows: and And satisfy the following relationship: , in, and These are the equivalent radii of the outer and inner annular heating zones, respectively. The equivalent radius is the arithmetic mean of the radial inner boundary radius and the radial outer boundary radius of the corresponding annular heating zone. This is the radial heat loss compensation coefficient, with a value ranging from 1.0 to 1.5; To improve the response speed and steady-state accuracy of zoned temperature control and reduce the lag and overshoot caused by relying solely on feedback adjustment, this invention employs a composite control algorithm combining feedforward and feedback in step S3: the controller... Each annular heating zone is arranged according to Calculate the heating power, where The base power, pre-set based on the average heat load of the area, is used to offset the "static" portion of the heat absorbed by the reaction and the heat dissipated radially. and These are the proportional and integral coefficients, used to dynamically correct for disturbances and residual biases. For real-time temperature difference; by introducing it into the power command The feedforward term allows the system to compensate for fluctuations in feed volume or changes in environmental heat dissipation without waiting for a significant increase in temperature deviation, thereby significantly shortening the temperature recovery time and reducing the amplitude of temperature fluctuations. When the annular heating zone includes an outer annular heating zone and an inner annular heating zone, considering the objective operating condition differences of the outer annular zone being closer to the shell, having greater radial heat dissipation, and being more prone to temperature drop, the base power of the outer annular zone and the inner annular zone are respectively denoted as... and and set it to satisfy ,in , The equivalent radius of the corresponding annular heating zone is the arithmetic mean of the radial inner boundary radius and the outer boundary radius of the annular zone. The radial heat loss compensation coefficient is set at 1.0 to 1.5; during implementation, the boundaries of each annular zone can be determined first based on the structural dimensions, and calculations can be performed. , Then, select based on insulation conditions and external wall heat dissipation level. And based on this, give and The ratio is then fine-tuned by the feedback term for transient disturbances in different ring regions, thereby achieving the control effect of "outer ring preferentially compensating for heat dissipation and inner ring finely maintaining the reaction temperature zone", further reducing radial temperature difference, suppressing hot spots and improving propylene yield and catalyst life.

[0027] It also includes an optimization step: dynamically adjusting the set value of the base power Pbase,i according to the changes in reactor feed flow rate or raw material concentration; and when a certain annular heating zone is cut off from power due to a fault, the target temperature Tset,j (j≠i) of its adjacent annular heating zone is increased accordingly to maintain the overall reactor processing efficiency, and the increased target temperature Tset,j does not exceed 630℃. To improve the continuous operation capability of the device under load changes and local fault conditions, this invention also includes an optimization step: when the reactor feed flow rate or raw material concentration changes, the controller updates the base power of each annular heating zone based on flow meter / component analysis or operational settings. (For example, increasing the feed rate will result in a corresponding increase) The decrease is due to the reduction in feed rate. This allows the feedforward term to adaptively cover changes in the "average heat load" according to operating conditions, avoiding temperature lag and large fluctuations caused by complete reliance on the feedback term. This ensures that the catalyst bed 8 temperature remains stable within the target temperature range and reduces energy consumption during load increases / decreases, start-ups / shutdowns, or raw material fluctuations. Simultaneously, when a certain annular heating zone is cut off from power due to an electrical fault, component damage, or protective interlock, the controller enters a fault degradation mode. While maintaining power outage and alarming in the faulty zone, it maintains the target temperature of the adjacent annular heating zone. ( The power command is moderately increased to compensate for the failure zone by utilizing bed thermal diffusion and radial heat conduction, and the power command of adjacent zones is adjusted simultaneously to maintain the overall reactor processing efficiency. A clear limit of 630℃ is established to ensure a safety boundary. Through this optimization strategy of "adaptive base power + fault adjacent zone compensation," system-wide downtime due to single-zone faults can be reduced without sacrificing safety, improving long-term operational stability and economy, and reducing the risk of localized coking and catalyst deactivation caused by uneven temperature. It should be further noted that 590℃~630℃ is the safe protection temperature boundary for reactor operation in this application, where 630℃ is the upper limit of over-temperature hard protection and 590℃ is the lower limit of low-temperature hard protection. The target control temperature Tset,i of each annular heating zone is preferably set within a sub-interval of the aforementioned safety threshold range to avoid overlap between the control target and the protection boundary. When the temperature of a certain area continuously exceeds 630℃ for a preset duration (e.g., 5s~30s), an alarm is triggered, and power reduction or power-off interlocking is executed. When the temperature recovers to below 630℃ and is lower than 630℃-ΔTh, the interlocking is released, thereby ensuring consistency between the temperature control logic and the safety interlocking logic and avoiding frequent actions at the boundary.

[0028] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0029] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A partitioned annular electrically heated radial propane dehydrogenation reactor, characterized in that, include: The reactor shell (1) has a reaction chamber (3) inside, and an insulation layer (2) is provided in the inner interlayer of the reactor shell (1). A radial bed structure (4) is disposed in the reaction chamber (3), including an inner cylinder (5) and an outer cylinder (6) arranged concentrically, and a catalyst bed (8) filled between the inner cylinder (5) and the outer cylinder (6). Multiple sets of flow holes (7) are provided on the cylinder walls of the inner cylinder (5) and the outer cylinder (6) so that the reaction medium can flow radially through the catalyst bed (8). The electric heat tracing system includes several electric heat tracing components and a power supply module. The electric heat tracing components are directly buried inside the catalyst bed (8) and divide the catalyst bed (8) into at least two independent concentric annular heating zones along the radial direction of the reactor shell (1). The electric heat tracing components in each annular heating zone are connected to an independent power supply branch of the power supply module. A temperature control system includes temperature sensors distributed within each of the annular heating zones, and a controller. The controller is electrically connected to each of the temperature sensors and each of the power supply branches, and is used to independently adjust the heating power of the corresponding annular heating zone based on the independent temperature monitoring data of each annular heating zone.

2. The partitioned annular electrically heated radial propane dehydrogenation reactor according to claim 1, characterized in that, The electric heat tracing assembly is further divided into at least two axial heating sections along the axial direction of the reactor shell (1). Each axial heating section is provided with an independent power supply branch. The controller is used to independently adjust the heating power of different axial heating sections.

3. The partitioned annular electrically heated radial propane dehydrogenation reactor according to claim 2, characterized in that, The electric heat tracing assembly is at least one of an electric heating rod, a flexible electric heating tape, or an electric heating plate; wherein the surface of the electric heating rod is provided with fins or heat transfer nails to increase the heat transfer area, and the electric heating plate is made of silicon carbide or graphene composite heating material.

4. The partitioned annular electrically heated radial propane dehydrogenation reactor according to claim 3, characterized in that, The division of the annular heating zone is designed based on the radial heat load distribution of the catalyst bed (8), and the ratio of the design heating power of the outer annular heating zone to that of the inner annular heating zone satisfies the following relationship: ,in, and The design heating power for the outer annular heating zone and the inner annular heating zone are respectively. and These are the equivalent radii of the outer and inner annular heating zones, respectively. This is the heat loss compensation coefficient, with a value ranging from 1.0 to 1.

5.

5. The partitioned annular electrically heated radial propane dehydrogenation reactor according to claim 1, characterized in that, The temperature control system also includes an alarm module; the controller is configured to trigger the alarm module and perform a safety interlock action of reducing the heating power of the zone or cutting off the power supply of the zone when the monitored temperature of any of the annular heating zones continuously exceeds the preset safety threshold range; the upper limit of the safety threshold range is 630℃ and the lower limit is 590℃.

6. The partitioned annular electrically heated radial propane dehydrogenation reactor according to claim 1, characterized in that, The inner cylinder (5) and the outer cylinder (6) are Johnson mesh structures, and their slit width is less than 2 mm; the upper part of the radial bed structure (4) is provided with a raw material distribution pipe, and the side wall of the raw material distribution pipe is provided with a number of distribution holes, the diameter of the distribution holes is 3 mm, and the opening rate of the raw material distribution pipe is 20%.

7. The partitioned annular electrically heated radial propane dehydrogenation reactor according to claim 1, characterized in that, The insulation layer (2) is made of aluminum silicate cotton or rock wool, and its thickness is 50–200 mm.

8. A heating method for a partitioned annular electrically heated radial propane dehydrogenation reactor, applied to the partitioned annular electrically heated radial propane dehydrogenation reactor as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Start the electric heat tracing system and heat the catalyst bed (8) through the electric heat tracing components of each annular heating zone; S2: Temperature data of each zone is collected in real time through temperature sensors distributed within each annular heating zone. ,in The numbering of the annular heating zone; S3: The controller will collect temperature data from each zone. and their respective preset target temperatures Compare and calculate real-time temperature difference Based on a preset collaborative control algorithm, it independently calculates and outputs power regulation signals for each power supply branch; S4: Based on the power adjustment signal, independently adjust the real-time heating power of each annular heating zone. To adjust the temperature of each zone Stabilize at the target temperature Nearby, thereby achieving a uniform radial temperature distribution in the catalyst bed (8); Wherein, the target temperature The value ranges from 590℃ to 630℃.

9. The heating method for a partitioned annular electrically heated radial propane dehydrogenation reactor according to claim 8, characterized in that, The cooperative control algorithm described in step S3 is a composite control algorithm that combines feedforward and feedback, specifically as follows: The controller is based on the formula Calculate the first Heating power of the zone; in, The numbering of the annular heating zone; For the first Real-time heating power of each annular heating zone; For the first The basic power setting value for each annular heating zone; and These are the proportional and integral coefficients of the controller, respectively. For real-time temperature difference; When the annular heating zone includes an outer annular heating zone and an inner annular heating zone, the outer annular heating zone has a larger equivalent radius, and the inner annular heating zone has a smaller equivalent radius. The base power settings for the outer annular heating zone and the inner annular heating zone are respectively denoted as... and And satisfy the following relationship: , in, and These are the equivalent radii of the outer and inner annular heating zones, respectively, where the equivalent radius is the arithmetic mean of the radial inner boundary radius and the radial outer boundary radius of the corresponding annular heating zone. This is the radial heat loss compensation coefficient, with a value ranging from 1.0 to 1.

5.

10. The heating method for a partitioned annular electrically heated radial propane dehydrogenation reactor according to claim 8, characterized in that, It also includes an optimization step: dynamically adjusting the set value of the base power Pbase,i according to the changes in reactor feed flow rate or raw material concentration; and when a certain annular heating zone is cut off from power due to a fault, correspondingly increasing the target temperature Tset,j (j≠i) of its adjacent annular heating zone to maintain the overall reactor processing efficiency, and the increased target temperature Tset,j does not exceed 630°C.

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