Multi-stage cold hydrogen grading temperature control method for high-pressure hydrogenation reactor

Abstract

The application discloses a kind of high-pressure hydrogenation reactor multi-stage cold hydrogen grading temperature control methods, belong to high-pressure hydrogenation reactor temperature control technical field.The method is set in the cold hydrogen injection unit of multiple catalyst bed between cold hydrogen injection manifold, and the temperature, pressure, hydrogen flow, cold hydrogen flow and pressure difference of each bed layer entrance and exit are collected;To the uppermost cold hydrogen injection point pulse injection cold hydrogen and record each downstream catalyst bed layer pressure fluctuation arrival time, form pressure wave arrival order;According to pressure wave arrival order and each catalyst bed layer temperature change time generation cold hydrogen branch opening sequence;According to opening sequence, gradually adjust the opening of cold hydrogen branch regulating valve and pass downstream control cycle upstream cold hydrogen flow and pressure data.The method makes cold hydrogen injection timing and bed dynamic response match, improves the stability of multi-stage cold hydrogen grading temperature control.

Description

Technical Field

[0001] This invention relates to the field of temperature control technology for high-pressure hydrogenation reactors, specifically a method for multi-stage cold hydrogen stage temperature control in high-pressure hydrogenation reactors. Background Technology

[0002] High-pressure hydrogenation reactors contain multiple catalyst beds. The exothermic reaction causes the bed temperatures to rise, necessitating the injection of cold hydrogen between the beds to control the reaction temperature. Current cold hydrogen injection control methods often employ fixed allocation or single-loop temperature feedback, adjusting the cold hydrogen branch valves based on the inlet or outlet temperature deviation of each catalyst bed. Due to differences in pressure wave propagation speed, temperature response time, and cold hydrogen mixing process among the beds, the opening sequence of the cold hydrogen branches is typically set according to bed numbering or experience, failing to reflect the actual timing of pressure fluctuations and temperature changes. Cold hydrogen injection can easily precede or lag behind the bed thermal dynamics, leading to localized overheating or overcooling. Downstream cold hydrogen branch regulation generally only utilizes the temperature signal of its own bed, failing to transmit upstream cold hydrogen flow and pressure data to the downstream control cycle. This lack of coordination between branch regulation actions easily leads to interstage temperature disturbances. The start-up timing and duration of cold hydrogen branches are often determined based on steady-state temperature difference or fixed timing sequences. There is a lack of a mechanism to adjust the operating parameters for the next cycle based on the correlation between the downstream bed temperature rise rate and the upstream cold hydrogen injection rate. When feed rate, hydrogen flow rate, or catalyst activity changes, the fixed timing sequence cannot meet the dynamic temperature control requirements of each bed. The multi-stage cold hydrogen staged temperature control in high-pressure hydrogenation reactors suffers from problems such as an unreasonable cold hydrogen branch start-up sequence due to the mismatch between the pressure wave arrival order and the temperature change timing, and the failure to use the correlation between the downstream temperature rise rate and the upstream cold hydrogen injection rate to adjust the start-up timing and duration of the cold hydrogen branches. Summary of the Invention

[0003] To address the shortcomings of existing methods that fail to match the timing of cold hydrogen injection with the dynamic response of the bed and cannot dynamically adjust the opening parameters of the cold hydrogen branch according to the downstream temperature rise rate, this invention provides a multi-stage cold hydrogen staged temperature control method for high-pressure hydrogenation reactors. This method involves pulsed injection of cold hydrogen into the uppermost cold hydrogen injection point and recording the arrival sequence of the pressure waves. This sequence is then paired with the temperature change times of each catalyst bed to generate a cold hydrogen branch opening sequence. Furthermore, the relationship between the downstream bed temperature rise rate and the upstream cold hydrogen injection amount is used to correct the opening time and duration of the cold hydrogen branch in the next cycle. This ensures that the cold hydrogen injection timing matches the dynamic response of the bed, improving the accuracy of multi-stage cold hydrogen staged temperature control.

[0004] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides a multi-stage cold hydrogen staged temperature control method for a high-pressure hydrogenation reactor, comprising: setting up a staged cold hydrogen injection unit on the cold hydrogen injection main pipe between multiple catalyst beds in the high-pressure hydrogenation reactor; collecting the temperature, pressure, hydrogen flow rate, cold hydrogen flow rate, and pressure difference at the inlet and outlet of each catalyst bed; pulse-injecting cold hydrogen to the uppermost cold hydrogen injection point; recording the arrival time of pressure fluctuations in each downstream catalyst bed to form a pressure wave arrival sequence; generating a cold hydrogen branch opening sequence based on the relationship between the pressure wave arrival sequence and the timing of temperature changes in each catalyst bed; adjusting the opening degree of the cold hydrogen branch regulating valves step by step according to the cold hydrogen branch opening sequence, and transmitting the upstream cold hydrogen flow rate and pressure data to the downstream control cycle; correcting the opening time and duration of each cold hydrogen branch in the next cycle based on the correspondence between the downstream bed temperature rise rate and the upstream cold hydrogen injection amount; and writing the corrected opening time and duration into the output channel of the staged cold hydrogen controller to control the valves of each cold hydrogen branch. This method generates an activation sequence by matching the pressure wave propagation order with the timing of temperature changes, and uses the upstream cold hydrogen flow rate and pressure as the initial values ​​of the downstream control cycle, so that each level of cold hydrogen branch can act according to the actual disturbance propagation characteristics, thereby improving the synergy of bed temperature control.

[0005] As a technical solution of this invention, when pulse-injecting cold hydrogen into the uppermost cold hydrogen injection point, the pressure regulating valve of the cold hydrogen injection main pipe is used as a guide. Within a set time window, the opening of the pressure regulating valve is increased in steps, while other cold hydrogen branch regulating valves are closed. The pressure of the cold hydrogen injection main pipe, the cold hydrogen flow rate, and the pressure of each downstream catalyst bed are collected. The arrival time of the pressure fluctuation peak at each catalyst bed is extracted, and the pressure wave arrival sequence is formed according to the time sequence. The pressure wave arrival sequence is sent to the staged cold hydrogen controller. This process, through step-by-step perturbation and peak arrival time identification, can obtain the transmission sequence of pressure waves between each bed without introducing large temperature disturbances.

[0006] Preferably, when increasing the pressure regulating valve opening in steps within a set time window, the set time window is divided into multiple consecutive time slots. Within each time slot, the pressure regulating valve opening remains constant, and the pressure of the cold hydrogen injection main pipe, the cold hydrogen flow rate, and the pressure of each downstream catalyst bed are collected. At the end of the time slot, the increase in the pressure regulating valve opening for the next time slot is determined based on the direction of change in the cold hydrogen injection main pipe pressure within the time slot. The increase in the pressure regulating valve opening for each time slot is sent to the pressure regulating valve in chronological order. If a pressure fluctuation occurs in any downstream catalyst bed, the step increase in the pressure regulating valve opening is stopped, and the current time slot number is sent to the staged cold hydrogen controller. This method gradually increases the pressure regulating valve opening in steps of time slots, enabling timely termination of disturbance inputs based on system response, and improving the stability and safety of pressure wave arrival order determination.

[0007] Preferably, when generating the cold hydrogen branch opening sequence, a correspondence table between bed numbers and cold hydrogen branch numbers is established in the staged cold hydrogen controller; the temperature change time of each catalyst bed is paired item by item with the arrival time of the corresponding bed in the pressure wave arrival sequence to obtain the pairing results; according to the pairing results, the cold hydrogen branch number corresponding to the catalyst bed whose temperature change time is earlier than the arrival time is shifted forward; according to the pairing results, the cold hydrogen branch number corresponding to the catalyst bed whose temperature change time is later than the arrival time is shifted backward; a cold hydrogen branch opening sequence containing the cold hydrogen branch number, opening time, and initial opening degree is generated, and the cold hydrogen branch opening sequence is sent to each cold hydrogen branch regulating valve. By comparing the timing of temperature change with the arrival time of pressure wave, the opening sequence of the cold hydrogen branches is corrected by shifting forward or backward, so that the opening sequence matches the actual dynamic response of the bed.

[0008] Preferably, when establishing the correspondence table between bed numbers and cold hydrogen branch numbers, the identifiers are read from the manhole number of the high-pressure hydrogenation reactor, the location of the catalyst bed support, and the orientation of the cold hydrogen injection port; the inlet temperature measuring point, outlet temperature measuring point, pressure measuring point of the catalyst bed, and the valve number of the cold hydrogen branch are numbered in the same row and column; the catalyst bed is arranged according to the material flow direction within the row and column to form the correspondence table between bed numbers and cold hydrogen branch numbers; the correspondence table between bed numbers and cold hydrogen branch numbers is stored in the staged cold hydrogen controller, and updated according to the identifiers after reactor maintenance; the updated correspondence table between bed numbers and cold hydrogen branch numbers is sent to the register in the staged cold hydrogen controller for matching the arrival order of pressure waves. This correspondence table can be updated according to the on-site identifiers after maintenance to avoid mismatch in the opening sequence due to changes in bed or branch numbers.

[0009] Preferably, when adjusting the opening degree of the cold hydrogen branch regulating valves step by step according to the cold hydrogen branch opening sequence, the staged cold hydrogen controller outputs opening commands sequentially according to the cold hydrogen branch opening sequence. For each stage of cold hydrogen branch opening, the instantaneous flow rate and pressure of the upstream cold hydrogen main pipe are collected, and the inlet and outlet temperatures of that stage of cold hydrogen branch are read. The instantaneous flow rate, pressure, inlet temperature, and outlet temperature are sent to the downstream control cycle via the fieldbus. The downstream control cycle uses the received instantaneous flow rate and pressure as the initial value for the next stage valve opening, and updates the next stage valve opening with this initial value before opening the next stage cold hydrogen branch. By transmitting the upstream measured flow rate and pressure along the control cycle, the initial value of the downstream valve opening can reflect the real-time changes in upstream cold hydrogen distribution, avoiding temperature fluctuations in each branch due to setpoint lag.

[0010] Preferably, when the downstream control cycle uses the received instantaneous flow rate and pressure as the initial value for the next-level valve opening, the downstream control cycle receives the instantaneous flow rate and pressure from the upstream cold hydrogen main pipe and reads the current valve opening, inlet temperature, and outlet temperature of the next-level cold hydrogen branch; it then forms a start-up data set for the next-level cold hydrogen branch based on the instantaneous flow rate, pressure, current valve opening, inlet temperature, and outlet temperature; it determines the action direction of the regulating valve in the next-level cold hydrogen branch according to the inlet temperature and outlet temperature in the start-up data set; it transmits the start-up data set and action direction to the next-next control cycle; and before the next-level cold hydrogen branch opens, it updates the current valve opening to the initial value of the next-level valve opening according to the action direction. This method incorporates temperature deviation into the action direction judgment, ensuring that the valve opening update direction of the next level is consistent with the actual heat exchange requirements of the bed.

[0011] Preferably, when correcting the start-up time and duration of each cold hydrogen branch in the next cycle based on the correspondence between the downstream bed temperature rise rate and the upstream cold hydrogen injection amount, the downstream bed temperature rise rate and the upstream cold hydrogen injection amount are collected according to the catalyst bed sequence number, and the downstream bed temperature rise rate and the upstream cold hydrogen injection amount at the same time are stored in the timing table of the staged cold hydrogen controller; when the temperature rise rate reaches the peak value of the catalyst bed in the current cycle, the upstream cold hydrogen injection amount at the corresponding time is recorded as the peak injection amount; based on the numerical sequence of the peak injection amount before and after the occurrence time of the peak injection amount in the catalyst bed, the start-up time and duration of the cold hydrogen branch in the next cycle are adjusted; the adjusted start-up time and duration of the cold hydrogen branch are written into the timing table of the staged cold hydrogen controller for the next cycle and sent to the regulating valve of each cold hydrogen branch. By using the time correspondence between the peak temperature rise rate and the peak injection amount to correct the parameters of the next cycle, the cold hydrogen injection duration can be dynamically matched for the exothermic response characteristics of different beds, reducing temperature overshoot.

[0012] Preferably, when adjusting based on the numerical sequence of the peak injection amount before and after the occurrence of the peak injection amount in the catalyst bed, the rising segment of the cold hydrogen injection amount before the occurrence of the peak injection amount and the falling segment of the cold hydrogen injection amount after the occurrence of the peak injection amount are recorded. If the duration of the rising segment is longer than that of the falling segment, the start time of the cold hydrogen branch in the next cycle is advanced, and the duration of the start time is extended. If the duration of the rising segment is shorter than that of the falling segment, the start time of the cold hydrogen branch in the next cycle is delayed, and the duration of the start time is shortened. The advanced or delayed start time and the extended or shortened duration of the start time are written into the timing table of the next cycle of the staged cold hydrogen controller according to the cold hydrogen branch number. The timing table of the next cycle is sent to the regulating valve of each cold hydrogen branch. By comparing the duration of the cold hydrogen injection amount before and after the peak injection amount, the speed of the endothermic response of each bed to cold hydrogen can be identified, and the start time and duration can be directionally corrected.

[0013] Preferably, when writing the corrected opening time and duration into the output channel of the graded cold hydrogen controller, an output register corresponding to each cold hydrogen branch is set in the graded cold hydrogen controller; the corrected opening time is converted into the time base count value of the graded cold hydrogen controller, and the opening duration is converted into the valve action pulse width; the time base count value and valve action pulse width are written into the corresponding output register according to the cold hydrogen branch number; the output register reads the time base count value and valve action pulse width according to the scan cycle, and drives the regulating valve of that cold hydrogen branch to act; the write status and read status of the output register are fed back to the timing table of the next cycle of the graded cold hydrogen controller. By converting the corrected opening time and duration into the time base count value and pulse width that the valve can execute through the output register, the action timing accuracy is improved, and the execution status is fed back to the next cycle, forming a closed-loop correction.

[0014] The technical effects and advantages provided by the present invention in the above technical solution are as follows: Cold hydrogen is pulsed into the uppermost cold hydrogen injection point. Within a set time window, the regulating valves of other cold hydrogen branches are closed. The pressure of the main cold hydrogen injection pipe, the cold hydrogen flow rate, and the pressure of each downstream catalyst bed are collected. The arrival time of the pressure fluctuation peak at each catalyst bed is extracted to form a pressure wave arrival sequence. The pressure wave arrival sequence is paired item by item with the temperature change time of each catalyst bed. For beds where the temperature change precedes the pressure wave arrival, the cold hydrogen branch number is shifted forward; for beds where the temperature change precedes the pressure wave arrival, the cold hydrogen branch number is shifted backward, generating a cold hydrogen branch opening sequence containing the cold hydrogen branch number, opening time, and initial opening degree. After pairing the pulse injection and pressure wave arrival sequence, the opening sequence of the cold hydrogen branches is determined based on the actual pressure wave propagation and temperature dynamic response of each bed. The cold hydrogen branch actions are no longer executed according to fixed numbers or empirical sequences. The timing of cold hydrogen injection is matched with the bed's thermal dynamics, reducing bed temperature fluctuations caused by premature or delayed cold hydrogen injection. A time series table is established based on the downstream bed temperature rise rate and the upstream cold hydrogen injection rate. When the temperature rise rate reaches the peak of the current cycle, the corresponding upstream cold hydrogen injection rate is recorded as the peak injection rate. The rising segment before the peak injection rate and the falling segment after the peak injection rate are compared. If the rising segment lasts longer than the falling segment, the opening time of the cold hydrogen branch in the next cycle is advanced and the opening duration is extended; if the rising segment lasts shorter than the falling segment, the opening time of the cold hydrogen branch in the next cycle is delayed and the opening duration is shortened. The operating parameters for the next cycle are corrected based on the numerical sequence before and after the peak injection rate, so that the opening time and duration of the cold hydrogen branch are dynamically adjusted according to the downstream bed temperature rise rate. This avoids adjustment lag or over-injection caused by setting only based on steady-state temperature difference, adapts to changes in feed rate and catalyst activity, and improves the uniformity of temperature distribution and operational stability of each catalyst bed. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0016] Figure 1 This is a flowchart of a multi-stage cold hydrogen stage temperature control method for a high-pressure hydrogenation reactor; Figure 2 This is a flowchart of the generation and distribution of the cold hydrogen branch activation sequence for the graded cold hydrogen controller. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] See Figure 1 This invention provides a multi-stage cold hydrogen staged temperature control method for a high-pressure hydrogenation reactor. A staged cold hydrogen injection unit is installed on the cold hydrogen injection main pipe between multiple catalyst beds in the high-pressure hydrogenation reactor. Temperature, pressure, hydrogen flow rate, cold hydrogen flow rate, and pressure difference are collected at the inlet and outlet of each catalyst bed. Cold hydrogen is pulsedly injected into the uppermost cold hydrogen injection point, and the arrival time of pressure fluctuations in each downstream catalyst bed is recorded to form a pressure wave arrival sequence. Based on the relationship between the pressure wave arrival sequence and the timing of temperature changes in each catalyst bed, a cold hydrogen branch opening sequence is generated. The opening degree of the cold hydrogen branch regulating valves is adjusted stage by stage according to the cold hydrogen branch opening sequence, and the upstream cold hydrogen flow rate and pressure data are transmitted to the downstream control cycle. Based on the correspondence between the downstream bed temperature rise rate and the upstream cold hydrogen injection amount, the opening time and duration of each cold hydrogen branch in the next cycle are corrected. The corrected opening time and duration are written into the output channel of the staged cold hydrogen controller to control the valves of each cold hydrogen branch.

[0019] In practice, the cold hydrogen injection main pressure regulating valve is used as a pilot valve. Within a set time window, the opening of the cold hydrogen injection main pressure regulating valve is increased in steps. Simultaneously, the staged cold hydrogen controller sends a closing command to the regulating valves of other cold hydrogen branches, causing the openings of the other cold hydrogen branch regulating valves to return to zero. The cold hydrogen injection main pressure regulating valve receives the step opening command output by the staged cold hydrogen controller and maintains its current opening constant within each time slot.

[0020] The time window is set by the staged cold hydrogen controller based on the number of catalyst beds in the high-pressure hydrogenation reactor and the length of the cold hydrogen injection manifold. The time window is divided into multiple consecutive time slots, each 200 milliseconds long. Within each time slot, the opening of the cold hydrogen injection manifold pressure regulating valve remains constant. The pressure of the cold hydrogen injection manifold is collected by a pressure transmitter installed on the manifold, the cold hydrogen flow rate is collected by a flow meter installed on the manifold, and the pressure of each downstream catalyst bed is collected by pressure measuring points installed on each downstream catalyst bed.

[0021] At the end of each time slot, the staged cold hydrogen controller determines the increase in the opening of the cold hydrogen injection main pressure regulating valve for the next time slot based on the direction of pressure change in the main cold hydrogen injection line during that time slot. The increase in the opening of the cold hydrogen injection main pressure regulating valve for the next time slot is calculated using the following formula:

[0022] in, Indicates the first The increase in the opening of the cold hydrogen injection main pressure regulating valve for each time slot, expressed as a percentage of opening. This represents the opening adjustment coefficient, which is 0.5% per 0.1 MPa. The opening adjustment coefficient is determined based on the flow characteristic curve of the cold hydrogen injection main pipe pressure regulating valve. Within the commonly used operating range, a 0.5% change in opening corresponds to a 0.1 MPa change in the cold hydrogen injection main pipe pressure. Indicates the first The change in cold hydrogen injection main pressure within each time slot, in MPa. The change in cold hydrogen injection manifold pressure within the first time slot is equal to the first... At the end of the time slot, the cold hydrogen injection main pressure is reduced by the first... The cold hydrogen injection manifold pressure at the start of each time slot.

[0023] The staged cold hydrogen controller sends the increase in the opening of the cold hydrogen injection main manifold pressure regulating valve for each time slot to the cold hydrogen injection main manifold pressure regulating valve in a chronological order. Specifically, the staged cold hydrogen controller adds the opening of the cold hydrogen injection main manifold pressure regulating valve in the current time slot to the calculated increase in the opening of the cold hydrogen injection main manifold pressure regulating valve in the next time slot, forming the opening command for the cold hydrogen injection main manifold pressure regulating valve in the next time slot, and writes the opening command for the cold hydrogen injection main manifold pressure regulating valve in the next time slot into the control loop of the cold hydrogen injection main manifold pressure regulating valve.

[0024] When a pressure fluctuation occurs in any downstream catalyst bed, the staged cold hydrogen controller stops the stepwise increase of the opening of the cold hydrogen injection main pressure regulating valve and sends the current time slot number to the pressure wave detection register inside the staged cold hydrogen controller. Pressure fluctuations in the downstream catalyst bed are determined as follows: when the change in pressure value collected at any downstream catalyst bed pressure measuring point relative to the pressure value collected in the previous sampling period exceeds the pressure fluctuation judgment threshold, a pressure fluctuation is determined to have occurred in that downstream catalyst bed. The pressure fluctuation judgment threshold is set to 0.05 MPa, and is determined based on the upper limit of catalyst bed pressure fluctuation during normal operation of the high-pressure hydrogenation reactor.

[0025] The staged cold hydrogen controller collects the pressure of the cold hydrogen injection main pipe, the cold hydrogen flow rate, and the pressure of each downstream catalyst bed. It performs peak detection on the pressure value sequence collected from each downstream catalyst bed pressure measurement point, and identifies the moment when the pressure value transitions from a gradual increase to a gradual decrease as the arrival time of the pressure fluctuation peak for that downstream catalyst bed. The staged cold hydrogen controller sorts the arrival times of the pressure fluctuation peaks of each downstream catalyst bed in chronological order, forming a pressure wave arrival sequence. This pressure wave arrival sequence is then written into an internal register for pressure wave arrival sequence matching.

[0026] In specific implementation, please refer to Figure 2 The staged cold hydrogen controller establishes a correspondence table between bed sequence numbers and cold hydrogen branch numbers. The staged cold hydrogen controller reads the manhole identifier from the manhole number of the high-pressure hydrogenation reactor; the manhole identifier is the string of manhole number marked on the manhole cover of each manhole in the high-pressure hydrogenation reactor. The staged cold hydrogen controller reads the support component position identifier from the catalyst bed support component position; the support component position identifier is the elevation value and azimuth angle of the catalyst bed support component on the high-pressure hydrogenation reactor shell. The staged cold hydrogen controller reads the cold hydrogen injection port orientation identifier from the cold hydrogen injection port orientation; the port orientation identifier is the angle between the centerline of the cold hydrogen injection port and the vertical centerline of the high-pressure hydrogenation reactor shell.

[0027] The staged cold hydrogen controller groups the catalyst bed inlet temperature measuring point, catalyst bed outlet temperature measuring point, catalyst bed pressure measuring point, and cold hydrogen branch valve numbers into the same row and column. The same row and column begins with the measuring point number of the catalyst bed inlet temperature measuring point, followed by the measuring point numbers of the catalyst bed outlet temperature measuring point, catalyst bed pressure measuring point, and cold hydrogen branch valve numbers.

[0028] The staged cold hydrogen controller arranges the catalyst beds in rows and columns according to the material flow direction. The material flow direction is from the top inlet of the high-pressure hydrogenation reactor to the bottom outlet of the high-pressure hydrogenation reactor. Each row and column corresponds to one catalyst bed, and adjacent rows and columns are separated by catalyst bed supports. The completed set of rows and columns forms a correspondence table between bed numbers and cold hydrogen branch numbers. The bed numbers increase sequentially starting from the top catalyst bed, with the top catalyst bed corresponding to bed number 1, and subsequent catalyst beds corresponding to bed numbers 2, 3, 4, and so on, until the bottom catalyst bed corresponds to the maximum bed number.

[0029] The staged cold hydrogen controller stores the correspondence table between bed numbers and cold hydrogen branch numbers in its non-volatile memory. After the high-pressure hydrogenation reactor is overhauled, the staged cold hydrogen controller rereads the manhole identifier from the manhole number of the high-pressure hydrogenation reactor, the support position identifier from the catalyst bed support location, and the port orientation identifier from the cold hydrogen injection port orientation. Based on the reread manhole identifier, support position identifier, and port orientation identifier, the staged cold hydrogen controller updates the correspondence table between bed numbers and cold hydrogen branch numbers.

[0030] The staged cold hydrogen controller sends the updated correspondence table between bed numbers and cold hydrogen branch numbers to the register within the staged cold hydrogen controller that performs pressure wave arrival order pairing. This register is a dedicated unit within the staged cold hydrogen controller used to store the correspondence between bed numbers and cold hydrogen branch numbers. The register unit stores the cold hydrogen branch number and the measurement point number of the catalyst bed inlet temperature measurement point sequentially according to the bed number.

[0031] The staged cold hydrogen controller pairs the time of temperature change of each catalyst bed with the arrival time of the corresponding bed in the pressure wave arrival sequence. The time of temperature change of the catalyst bed is the moment when the temperature value collected by the inlet temperature measuring point of the catalyst bed exceeds the temperature change threshold of the catalyst bed. The temperature change threshold of the catalyst bed is obtained by subtracting the current operating temperature from the upper limit of the allowable temperature rise of the catalyst bed specified in the high-pressure hydrogenation reactor process design document. The arrival time of the corresponding bed in the pressure wave arrival sequence is the arrival time of the peak pressure wave for that catalyst bed read by the staged cold hydrogen controller from the pressure wave arrival sequence register. During pairing, the staged cold hydrogen controller aligns the time of temperature change of the catalyst bed with the arrival time of the same bed number in the pressure wave arrival sequence to form a pairing result.

[0032] The staged cold hydrogen controller, based on the catalyst bed whose temperature change time is earlier than its arrival time in the pairing results, shifts the cold hydrogen branch number corresponding to that catalyst bed forward. Shifting the cold hydrogen branch number forward means moving the branch number one position ahead of the cold hydrogen branch opening sequence. Conversely, the staged cold hydrogen controller, based on the catalyst bed whose temperature change time is later than its arrival time in the pairing results, shifts the cold hydrogen branch number corresponding to that catalyst bed backward. Shifting the cold hydrogen branch number backward means moving the branch number one position behind the cold hydrogen branch opening sequence.

[0033] The staged cold hydrogen controller generates a cold hydrogen branch opening sequence including the cold hydrogen branch number, opening time, and initial opening degree. The cold hydrogen branch number is the branch number after shifting forward or backward. The opening time is calculated by the staged cold hydrogen controller based on the total feed flow rate of the high-pressure hydrogenation reactor and the pressure difference between each catalyst bed, with a resolution of 1 second. The initial opening degree is calculated by the staged cold hydrogen controller based on the cold hydrogen branch flow characteristic curve corresponding to the cold hydrogen branch valve number and the upstream cold hydrogen mains pressure of the cold hydrogen branch, with the initial opening degree expressed as an opening percentage.

[0034] The staged cold hydrogen controller sends the cold hydrogen branch opening sequence to each cold hydrogen branch control valve. During the sending process, the staged cold hydrogen controller writes the opening time and initial opening degree corresponding to each cold hydrogen branch number in the opening sequence into the positioner register of the corresponding cold hydrogen branch control valve via the fieldbus. After receiving the written opening time and initial opening degree, the positioner register of the cold hydrogen branch control valve executes the valve action according to the initial opening degree when the opening time arrives.

[0035] In practice, the staged cold hydrogen controller outputs opening commands sequentially according to the cold hydrogen branch opening sequence. The cold hydrogen branch opening sequence is stored in the sequence register inside the staged cold hydrogen controller, and includes the cold hydrogen branch number, opening time, and initial opening degree. The staged cold hydrogen controller reads the cold hydrogen branch number and initial opening degree from the opening sequence line by line according to the order of opening times, and outputs the opening command to the corresponding cold hydrogen branch regulating valve.

[0036] Each time a first-stage cold hydrogen branch is activated, a flow meter installed on the cold hydrogen injection main pipe collects the instantaneous flow rate of the upstream cold hydrogen main pipe of the current-stage cold hydrogen branch, a pressure transmitter installed on the cold hydrogen injection main pipe collects the pressure of the upstream cold hydrogen main pipe of the current-stage cold hydrogen branch, an inlet temperature measuring point installed on the current-stage cold hydrogen branch reads the inlet temperature of the current-stage cold hydrogen branch, and an outlet temperature measuring point installed on the current-stage cold hydrogen branch reads the outlet temperature of the current-stage cold hydrogen branch.

[0037] The instantaneous flow rate, pressure, inlet temperature, and outlet temperature of the current-stage cold hydrogen branch's upstream cold hydrogen main pipe are transmitted to the downstream control cycle via a fieldbus. The fieldbus uses an RS485 bus, and its data frame contains four data fields: instantaneous flow rate, pressure, inlet temperature, and outlet temperature of the current-stage cold hydrogen branch's upstream cold hydrogen main pipe.

[0038] The downstream control cycle uses the instantaneous flow rate of the upstream cold hydrogen main pipe of the current-stage cold hydrogen branch and the pressure of the upstream cold hydrogen main pipe of the current-stage cold hydrogen branch as the initial value of the regulating valve opening of the next-stage cold hydrogen branch. The initial value of the regulating valve opening of the next-stage cold hydrogen branch is calculated according to the following formula:

[0039] in, This indicates the initial opening value of the regulating valve in the next-level cold hydrogen branch, expressed as a percentage of opening. This represents the conversion factor for flow rate, pressure, and opening degree of the cold hydrogen branch, with units of opening percentage·MPa·h / standard cubic meter, and a value of [value missing]. The value is determined based on the rated flow coefficient of the regulating valve in the next-level cold hydrogen branch and the inner diameter of the cold hydrogen branch pipeline. This indicates the instantaneous flow rate of the upstream cold hydrogen main pipe of the current-level cold hydrogen branch, expressed in standard cubic meters per hour. This indicates the pressure in the upstream cold hydrogen main pipe of the current cold hydrogen branch, expressed in megapascals (MPA).

[0040] The downstream control cycle receives the instantaneous flow rate and pressure of the upstream cold hydrogen main pipe of the current cold hydrogen branch, and reads the current valve opening of the next-level cold hydrogen branch through the valve position feedback sensor of the regulating valve of the next-level cold hydrogen branch, reads the inlet temperature of the next-level cold hydrogen branch through the inlet temperature measuring point of the next-level cold hydrogen branch, and reads the outlet temperature of the next-level cold hydrogen branch through the outlet temperature measuring point of the next-level cold hydrogen branch.

[0041] The startup data set for the next-stage cold hydrogen branch consists of the instantaneous flow rate of the upstream cold hydrogen main pipe of the current-stage cold hydrogen branch, the pressure of the upstream cold hydrogen main pipe of the current-stage cold hydrogen branch, the current valve opening of the next-stage cold hydrogen branch, the inlet temperature of the next-stage cold hydrogen branch, and the outlet temperature of the next-stage cold hydrogen branch. The startup data set for the next-stage cold hydrogen branch is stored in the following order: instantaneous flow rate of the upstream cold hydrogen main pipe of the current-stage cold hydrogen branch, pressure of the upstream cold hydrogen main pipe of the current-stage cold hydrogen branch, current valve opening of the next-stage cold hydrogen branch, inlet temperature of the next-stage cold hydrogen branch, and outlet temperature of the next-stage cold hydrogen branch.

[0042] The direction of action of the regulating valve for the next-stage cold hydrogen branch is determined by the inlet and outlet temperatures of the next-stage cold hydrogen branch in the start-up data group of the next-stage cold hydrogen branch. When the inlet temperature of the next-stage cold hydrogen branch is higher than its outlet temperature, the regulating valve decreases its opening. When the inlet temperature of the next-stage cold hydrogen branch is lower than its outlet temperature, the regulating valve increases its opening. When the inlet temperature of the next-stage cold hydrogen branch equals its outlet temperature, the regulating valve maintains its current opening.

[0043] The start-up data set of the next-level cold hydrogen branch and the operating direction of the next-level cold hydrogen branch control valve are transmitted to the next-next control cycle. During transmission, the staged cold hydrogen controller writes the start-up data set of the next-level cold hydrogen branch and the operating direction of the next-level cold hydrogen branch control valve into the receive buffer of the next-next control cycle via the fieldbus. The receive buffer of the next-next control cycle stores all data fields in the start-up data set of the next-level cold hydrogen branch and the operating direction of the next-level cold hydrogen branch control valve.

[0044] Before the next-level cold hydrogen branch is activated, the staged cold hydrogen controller reads the start-up data group of the next-level cold hydrogen branch from the receive buffer of the next-level control cycle. It replaces the current valve opening of the next-level cold hydrogen branch in the start-up data group with the calculated initial value of the regulating valve opening of the next-level cold hydrogen branch. Then, it writes the replaced initial value of the regulating valve opening of the next-level cold hydrogen branch into the positioner register of the regulating valve of the next-level cold hydrogen branch according to the direction of action of the regulating valve of the next-level cold hydrogen branch, thus completing the opening update of the regulating valve of the next-level cold hydrogen branch.

[0045] In implementation, the staged cold hydrogen controller collects the downstream bed temperature rise rate and upstream cold hydrogen injection rate according to the catalyst bed sequence number. The catalyst bed sequence number increases sequentially from the uppermost catalyst bed to the lower layers. The downstream bed temperature rise rate is obtained by dividing the difference between the temperature value collected from the catalyst bed outlet temperature measuring point and the temperature value collected from the catalyst bed inlet temperature measuring point by the sampling period, which is set to 1 second. The upstream cold hydrogen injection rate is collected by a flow meter installed on the cold hydrogen injection manifold. The flow meter outputs a current signal of 4 mA to 20 mA. The staged cold hydrogen controller converts the current signal into a cold hydrogen injection rate value, in standard cubic meters per hour. The staged cold hydrogen controller combines the downstream bed temperature rise rate and the upstream cold hydrogen injection rate at the same moment into a data pair and stores the data pair in the staged cold hydrogen controller's time series table. The time series table contains four fields: catalyst bed sequence number, timestamp, downstream bed temperature rise rate, and upstream cold hydrogen injection rate. The timestamp is the internal time base count value of the staged cold hydrogen controller, with a timestamp resolution of 1 second.

[0046] In some embodiments, the staged cold hydrogen controller determines the peak value of the downstream bed temperature rise rate for each catalyst bed in each sampling cycle. When the downstream bed temperature rise rate in the current sampling cycle is greater than that in the previous sampling cycle, and also greater than that in the next sampling cycle, the staged cold hydrogen controller determines the downstream bed temperature rise rate in the current sampling cycle as the peak value for that catalyst bed in the current cycle. The staged cold hydrogen controller records the upstream cold hydrogen injection amount at the moment the peak value occurs as the peak injection amount. The peak injection amount is obtained by the staged cold hydrogen controller reading the upstream cold hydrogen injection amount corresponding to the moment the peak value occurs from the time series table, and the peak injection amount is stored in the peak injection amount field of the time series table of the staged cold hydrogen controller.

[0047] In practical implementation, the staged cold hydrogen controller determines the rising and falling segments of cold hydrogen injection based on the numerical sequences before and after the peak injection amount appears in the catalyst bed. Starting from the timestamp corresponding to the peak injection amount, the staged cold hydrogen controller searches backwards in the time series table for the upstream cold hydrogen injection amount of the same catalyst bed number until it finds a starting timestamp where the upstream cold hydrogen injection amount no longer increases for two consecutive sampling periods. The time interval between the starting timestamp and the timestamp corresponding to the peak injection amount is recorded as the rising segment of cold hydrogen injection. Similarly, starting from the timestamp corresponding to the peak injection amount, the staged cold hydrogen controller searches backwards in the time series table for the upstream cold hydrogen injection amount of the same catalyst bed number until it finds an ending timestamp where the upstream cold hydrogen injection amount no longer decreases for two consecutive sampling periods. The time interval between the timestamp corresponding to the peak injection amount and the ending timestamp is recorded as the falling segment of cold hydrogen injection. The duration of the rising segment is obtained by subtracting the starting timestamp from the timestamp corresponding to the peak injection amount, and the duration of the falling segment is obtained by subtracting the timestamp corresponding to the peak injection amount from the ending timestamp. The staged cold hydrogen controller records the duration of the cold hydrogen injection rise phase as... The duration of the cold hydrogen injection rate decrease phase is denoted as... , and All units are seconds.

[0048] Optionally, the staged cold hydrogen controller adjusts the cold hydrogen injection rate based on the duration of the rising phase. Duration of the cold hydrogen injection decrease phase The difference is used to calculate the adjustment amount at the start time of the cold hydrogen branch in the next cycle. The calculation formula is as follows:

[0049] in, This indicates the adjustment amount for when the cold hydrogen branch will start in the next cycle, in seconds. A positive value indicates that the cold hydrogen branch will start earlier in the next cycle. A negative value indicates that the start time of the cold hydrogen branch in the next cycle is delayed; This represents the time scale conversion factor, with a value of 1.0. The basis for setting the time scale conversion factor to 1.0 is to directly use the difference between the duration of the cold hydrogen injection rise segment and the duration of the cold hydrogen injection fall segment as the adjustment amount for the opening time of the cold hydrogen branch in the next cycle. The units for the duration of the cold hydrogen injection rise segment, the duration of the cold hydrogen injection fall segment, and the adjustment amount for the opening time of the cold hydrogen branch in the next cycle are the same, all in seconds. This indicates the duration of the cold hydrogen injection rate increase, in seconds. The duration of the cold hydrogen injection rate increase is obtained by subtracting the start timestamp from the timestamp corresponding to the peak injection rate. This indicates the duration of the cold hydrogen injection rate decrease, in seconds. The duration of the cold hydrogen injection rate decrease is obtained by subtracting the timestamp corresponding to the peak injection rate from the end timestamp.

[0050] When the duration of the rising phase of the cold hydrogen injection rate is longer than the duration of the falling phase of the cold hydrogen injection rate. Greater than , If the value is greater than 0, the staged cold hydrogen controller will advance the start time of this cold hydrogen branch in the next cycle by an advance amount of 0. The absolute value of the cold hydrogen injection rate is used to extend the duration of the cold hydrogen branch's operation in the next cycle, with the extension duration being the same as the advance amount. When the duration of the cold hydrogen injection rate increase is shorter than the duration of the cold hydrogen injection rate decrease... Less than , If the value is less than 0, the staged cold hydrogen controller will delay the start-up time of this cold hydrogen branch in the next cycle by an amount of [missing value]. The absolute value of the cold hydrogen branch is determined, and the duration of its operation in the next cycle is shortened by the same amount as the delay.

[0051] In practical implementation, the tiered cold hydrogen controller writes the start time of the next cycle's cold hydrogen branch (advanced or delayed) and the duration of its operation (extended or shortened) into the next cycle's timing table according to the cold hydrogen branch number. The next cycle timing table contains three fields: cold hydrogen branch number, next cycle cold hydrogen branch start time, and next cycle cold hydrogen branch operation duration. The tiered cold hydrogen controller first reads the start time and operation duration corresponding to the cold hydrogen branch number in the current cycle's timing table. Then, it adds the next cycle cold hydrogen branch start time adjustment amount to the start time to obtain the new start time. If the next cycle cold hydrogen branch start time adjustment amount is positive, the new start time equals the original start time minus the absolute value of the adjustment amount; if the next cycle cold hydrogen branch start time adjustment amount is negative, the new start time equals the original start time plus the absolute value of the adjustment amount. The tiered cold hydrogen controller then writes the new start time into the next cycle cold hydrogen branch start time field corresponding to the cold hydrogen branch number in the next cycle's timing table. The staged cold hydrogen controller adds or subtracts the absolute value of the adjustment amount from the original start duration to obtain a new start duration, and writes the new start duration into the start duration field of the cold hydrogen branch corresponding to the cold hydrogen branch number in the next cycle timing table.

[0052] In some embodiments, the staged cold hydrogen controller sends the next cycle timing table to each cold hydrogen branch control valve. The staged cold hydrogen controller writes the next cycle cold hydrogen branch start time and the next cycle cold hydrogen branch start duration corresponding to each cold hydrogen branch number in the next cycle timing table into the positioner register of the corresponding cold hydrogen branch control valve via the fieldbus. Upon receiving the next cycle cold hydrogen branch start time and the next cycle cold hydrogen branch start duration, the positioner register of the cold hydrogen branch control valve updates the timer setting value and action pulse width setting value internally. After transmission is complete, the staged cold hydrogen controller writes the transmission completion status to the next cycle timing table status register of the staged cold hydrogen controller.

[0053] In practical implementation, the staged cold hydrogen controller sets up output registers in its digital output unit that correspond one-to-one with each cold hydrogen branch. Each output register corresponds to a regulating valve in a cold hydrogen branch, and includes a time base count value storage unit and a valve action pulse width storage unit. The time base count value storage unit stores the staged cold hydrogen controller time base count value obtained by converting the corrected opening time, and the valve action pulse width storage unit stores the valve action pulse width obtained by converting the opening duration. The output register address corresponds one-to-one with the cold hydrogen branch number, starting from 0 and sequentially from 1. Output register address 0 corresponds to cold hydrogen branch number 1, output register address 1 corresponds to cold hydrogen branch number 2, and so on.

[0054] The staged cold hydrogen controller reads the corrected start-up time and start-up duration from the timing table of the next cycle according to the cold hydrogen branch number. The corrected start-up time is the time offset relative to the start time of the next cycle, in seconds. The staged cold hydrogen controller converts the corrected start-up time into a staged cold hydrogen controller time base count value. The staged cold hydrogen controller's internal timer generates counting pulses according to the scan cycle. The staged cold hydrogen controller's scan cycle is set to 0.05 seconds per count. This 0.05-second count cycle is based on the fact that the staged cold hydrogen controller's internal timer has a counting frequency of 20 Hz and a counting period of 50 milliseconds, generating one counting pulse every 50 milliseconds, with one counting pulse corresponding to 0.05 seconds. The staged cold hydrogen controller time base count value is calculated using the following formula:

[0055] in, This represents the time base count value of the staged cold hydrogen controller, a dimensionless integer. This indicates the corrected start-up time in seconds. The corrected start-up time is read by the staged cold hydrogen controller from the next cycle cold hydrogen branch start-up time field of the corresponding cold hydrogen branch number in the next cycle timing table. This indicates the scanning cycle of the graded cold hydrogen controller, in seconds per count. The scanning cycle of the graded cold hydrogen controller is set to 0.05 seconds per count. The scanning cycle of the graded cold hydrogen controller is set based on the counting frequency of the internal timer of the graded cold hydrogen controller being 20 Hz and the counting cycle being 50 milliseconds.

[0056] The staged cold hydrogen controller converts the on-duration duration into valve action pulse width. The on-duration duration is the time, in seconds, required for the cold hydrogen branch control valve to maintain the drive signal. The staged cold hydrogen controller divides the on-duration duration by its scan cycle and rounds down to obtain the valve action pulse width. The valve action pulse width represents the number of scan cycles required to maintain the drive signal for the cold hydrogen branch control valve. The staged cold hydrogen controller writes the staged cold hydrogen controller time base count value to the corresponding output register's time base count value storage unit according to the cold hydrogen branch number, and writes the valve action pulse width to the corresponding output register's valve action pulse width storage unit. The writing order is ascending order of the cold hydrogen branch numbers. After writing is complete, the output register sets the write status to "write successful"; if an error occurs during the write process, the output register sets the write status to "write failed".

[0057] In some embodiments, the output register reads the time base count value and valve action pulse width according to the scan cycle of the staged cold hydrogen controller. At the beginning of each scan cycle, the output register reads the staged cold hydrogen controller time base count value from the time base count value storage unit and the valve action pulse width from the valve action pulse width storage unit. The output register compares the read staged cold hydrogen controller time base count value with the current count value of the staged cold hydrogen controller's internal timer. When the current count value of the staged cold hydrogen controller's internal timer is equal to the read staged cold hydrogen controller time base count value, the output register outputs a drive signal to the corresponding cold hydrogen branch regulating valve. The duration of the drive signal is equal to the valve action pulse width multiplied by the staged cold hydrogen controller scan cycle. After outputting the drive signal, the output register sets the read status to read successful; if the output register does not read a valid staged cold hydrogen controller time base count value or valve action pulse width within the scan cycle, the read status is set to read failed.

[0058] Optionally, the staged cold hydrogen controller feeds back the write and read statuses of the output registers to the timing table for the next cycle. At the end of each scan cycle, the staged cold hydrogen controller reads the write and read statuses of each output register, writes the write status corresponding to the cold hydrogen branch number to the write status field of the corresponding cold hydrogen branch number in the timing table for the next cycle, and writes the read status corresponding to the cold hydrogen branch number to the read status field of the corresponding cold hydrogen branch number in the timing table for the next cycle. The write status field and read status field in the timing table for the next cycle are used to record the write and read results of the output registers for the staged cold hydrogen controller's time base count value and valve action pulse width, respectively. Based on the write failure status in the write status field or the read failure status in the read status field, the staged cold hydrogen controller re-executes the write operation for the staged cold hydrogen controller's time base count value and valve action pulse width for the corresponding cold hydrogen branch number before the start of the next cycle.

[0059] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for controlling the temperature of multi-stage cold hydrogen stage in a high-pressure hydrogenation reactor, characterized in that, include: A staged cold hydrogen injection unit is set up on the cold hydrogen injection main pipe between multiple catalyst beds in the high-pressure hydrogenation reactor to collect the temperature, pressure, hydrogen flow rate, cold hydrogen flow rate, and pressure difference at the inlet and outlet of each catalyst bed. Cold hydrogen is pulsed into the uppermost cold hydrogen injection point, and the arrival time of pressure fluctuations in each downstream catalyst bed is recorded to form the pressure wave arrival sequence. Based on the relationship between the arrival order of pressure waves and the timing of temperature changes in each catalyst bed, a cold hydrogen branch opening sequence is generated. The opening degree of the cold hydrogen branch regulating valve is adjusted step by step according to the opening sequence of the cold hydrogen branch, and the upstream cold hydrogen flow and pressure data are transmitted to the downstream control cycle. Based on the relationship between the downstream bed temperature rise rate and the upstream cold hydrogen injection volume, the start-up time and duration of each cold hydrogen branch in the next cycle are adjusted. The corrected start time and duration are written into the output channel of the staged cold hydrogen controller to control the valves of each cold hydrogen branch.

2. The method for multi-stage cold hydrogen stage temperature control in a high-pressure hydrogenation reactor according to claim 1, characterized in that, The steps for pulse-injecting cold hydrogen into the uppermost cold hydrogen injection point include: With the pressure regulating valve of the cold hydrogen injection main as the lead, the opening of the pressure regulating valve is increased in steps within a set time window, while other cold hydrogen branch regulating valves are closed. Collect the pressure of the cold hydrogen injection main pipe, the cold hydrogen flow rate, and the pressure of each downstream catalyst bed. Extract the time when the pressure fluctuation peak reaches each catalyst bed and form the pressure wave arrival order according to the time sequence. The pressure wave arrival order is sent to the staged cold hydrogen controller.

3. The method for multi-stage cold hydrogen stage temperature control in a high-pressure hydrogenation reactor according to claim 1, characterized in that, Based on the relationship between the arrival order of pressure waves and the timing of temperature changes in each catalyst bed, the steps for generating the cold hydrogen branch activation sequence include: Establish a correspondence table between bed sequence number and cold hydrogen branch number in the staged cold hydrogen controller; The temperature change time of each catalyst bed was matched with the arrival time of the corresponding bed in the order of pressure wave arrival to obtain the matching results; Based on the catalyst bed whose temperature change time is earlier than the arrival time in the pairing results, the cold hydrogen branch number corresponding to that catalyst bed is moved forward. Based on the catalyst bed whose temperature change time is later than the arrival time in the pairing results, the cold hydrogen branch number corresponding to that catalyst bed is shifted to the next step. Generate a cold hydrogen branch opening sequence containing the cold hydrogen branch number, opening time, and initial opening degree, and send the cold hydrogen branch opening sequence to each cold hydrogen branch regulating valve.

4. The method for multi-stage cold hydrogen stage temperature control in a high-pressure hydrogenation reactor according to claim 1, characterized in that, The steps of adjusting the opening degree of the cold hydrogen branch regulating valve step by step according to the cold hydrogen branch opening sequence, and transmitting the upstream cold hydrogen flow and pressure data to the downstream control cycle, include: The staged cold hydrogen controller outputs opening commands sequentially according to the opening sequence of the cold hydrogen branches; Each time a cold hydrogen branch is opened, the instantaneous flow rate and pressure of the upstream cold hydrogen main pipe of that branch are collected, and the inlet and outlet temperatures of that cold hydrogen branch are read. Instantaneous flow rate, pressure, inlet temperature, and outlet temperature are sent to the downstream control cycle via fieldbus; The downstream control cycle uses the received instantaneous flow rate and pressure as the initial value of the next-level valve opening, and updates the next-level valve opening with this initial value before the next-level cold hydrogen branch is opened.

5. The method for multi-stage cold hydrogen stage temperature control in a high-pressure hydrogenation reactor according to claim 1, characterized in that, Based on the correlation between the downstream bed temperature rise rate and the upstream cold hydrogen injection volume, the steps for correcting the start-up time and duration of each cold hydrogen branch in the next cycle include: The downstream bed temperature rise rate and upstream cold hydrogen injection amount are collected according to the catalyst bed number, and the downstream bed temperature rise rate and upstream cold hydrogen injection amount at the same time are stored in the time series table of the staged cold hydrogen controller. When the rate of temperature rise reaches the peak value of the catalyst bed in the current cycle, the upstream cold hydrogen injection amount at the corresponding moment is recorded as the peak injection amount; Based on the numerical sequence of peak injection volume before and after the occurrence of peak injection volume in the catalyst bed, adjust the start time and duration of the cold hydrogen branch in the next cycle. The adjusted start time and duration of the cold hydrogen branch are written into the timing table of the next cycle of the staged cold hydrogen controller and sent to the regulating valves of each cold hydrogen branch.

6. The method for multi-stage cold hydrogen stage temperature control in a high-pressure hydrogenation reactor according to claim 2, characterized in that, The steps for increasing the opening of the pressure regulating valve in steps within a set time window include: Divide the set time window into multiple consecutive time slots; Keep the opening of the pressure regulating valve constant in each time slot, and collect the cold hydrogen injection main pressure, cold hydrogen flow rate and pressure of each downstream catalyst bed; At the end of the time slot, the increase in the opening of the pressure regulating valve in the next time slot is determined based on the direction of change of the cold hydrogen injection main pressure within the time slot. The increase in the opening of the pressure regulating valve in each time slot is sent to the pressure regulating valve in chronological order. When a pressure fluctuation occurs in any downstream catalyst bed, the pressure regulating valve opening increment is stopped, and the current time slot number is sent to the staged cold hydrogen controller.

7. The method for multi-stage cold hydrogen stage temperature control in a high-pressure hydrogenation reactor according to claim 1, characterized in that, The steps for writing the corrected start-up time and duration into the output channel of the staged cold hydrogen controller include: In the staged cold hydrogen controller, an output register is set up that corresponds one-to-one with each cold hydrogen branch; The corrected opening time is converted into the time base count value of the staged cold hydrogen controller, and the opening duration is converted into the valve action pulse width. Write the time base count value and valve action pulse width into the corresponding output register according to the cold hydrogen branch number; The output register reads the time base count value and valve action pulse width according to the scan cycle, and drives the regulating valve of the cold hydrogen branch to act. The write and read status of the output register are fed back to the timing table of the next cycle of the staged cold hydrogen controller.

8. The method for multi-stage cold hydrogen stage temperature control in a high-pressure hydrogenation reactor according to claim 3, characterized in that, The steps for establishing a correspondence table between bed numbers and cold hydrogen branch numbers in a staged cold hydrogen controller include: Read the markings from the manhole number, catalyst bed support location, and cold hydrogen injection port orientation of the high-pressure hydrogenation reactor; The inlet temperature measuring point, outlet temperature measuring point, pressure measuring point, and cold hydrogen branch valve number of the catalyst bed are numbered in the same row; The catalyst beds are arranged in rows and columns according to the material flow direction, forming a correspondence table between the bed number and the cold hydrogen branch number; The correspondence table between bed number and cold hydrogen branch number is stored in the staged cold hydrogen controller, and the correspondence table between bed number and cold hydrogen branch number is updated according to the identification after reactor maintenance. The updated table of correspondence between bed number and cold hydrogen branch number is sent to the register in the staged cold hydrogen controller to perform pressure wave arrival order pairing.

9. The method for multi-stage cold hydrogen stage temperature control in a high-pressure hydrogenation reactor according to claim 4, characterized in that, The downstream control cycle uses the received instantaneous flow rate and pressure as the initial value for the next-stage valve opening, and updates the next-stage valve opening with this initial value before the next-stage cold hydrogen branch opens. This includes the following steps: The downstream control cycle receives the instantaneous flow rate and pressure from the upstream cold hydrogen main pipe and reads the current valve opening, inlet temperature and outlet temperature of the next-level cold hydrogen branch. The instantaneous flow rate, pressure, current valve opening, inlet temperature, and outlet temperature are combined to form the startup data set for the next stage of the cold hydrogen branch; Determine the direction of action of the next-stage cold hydrogen branch regulating valve based on the inlet and outlet temperatures in the startup data set. The start data set and action direction will be passed to the next level of control cycle; Before the next stage cold hydrogen branch is opened, the current valve opening is updated to the initial value of the next stage valve opening according to the direction of action.

10. The method for multi-stage cold hydrogen stage temperature control in a high-pressure hydrogenation reactor according to claim 5, characterized in that, The steps for adjusting the start-up time and duration of the cold hydrogen branch in the next cycle, based on the numerical sequence of injection rates before and after the peak injection rate appears in the catalyst bed, include: Record the rising segment of cold hydrogen injection volume before the peak injection volume occurs and the falling segment of cold hydrogen injection volume after the peak injection volume occurs; If the rising segment lasts longer than the falling segment, the start time of the cold hydrogen branch in the next cycle will be brought forward, and the duration of the start-up will be extended. If the duration of the rising segment is shorter than that of the falling segment, the start time of the cold hydrogen branch in the next cycle will be delayed and the duration of the start-up will be shortened. Write the earlier or later start time and the extended or shortened start duration into the next cycle timing table of the tiered cold hydrogen controller according to the cold hydrogen branch number. The timing table for the next cycle is sent to the regulating valves of each cold hydrogen branch.

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