Energy consumption optimization control method and system for vacuum system used in plant oil refining

Abstract

The present application relates to the technical field of plant oil refining vacuum control, in particular to an energy consumption optimization control method and system for a vacuum system used in plant oil refining. In view of the problem that during the stage switching of the multiple vacuum units of plant oil refining, the residual negative pressure is directly discharged, the target unit to be pre-pumped is still repeatedly pre-pumped by the vacuum pump, the suction energy consumption is relatively high, and the process isolation risk is difficult to balance, the stage switching signal, the cavity pressure, the volume configuration, the process configuration, and the controllable communication path state are acquired, the residual negative pressure source vacuum unit and the target vacuum unit to be pre-pumped are identified, the target negative pressure volume to be discharged is formed based on an industrial vacuum mechanism model, the negative pressure volume is matched and the target communication path is determined when the process isolation condition is met, the vacuum pump is controlled to reduce the load and perform flow limiting and pressure equalization, and then the pre-pumping control instruction and the closing instruction are generated according to the target pressure after the pressure equalization, so that the energy-saving pre-pumping control of the vacuum system used in plant oil refining is applicable.

Description

Technical Field

[0001] This invention relates to the field of vacuum control technology for vegetable oil refining, specifically to an energy consumption optimization control method and system for vacuum systems used in vegetable oil refining. Background Technology

[0002] In the vegetable oil refining process, dehydration, deodorization, and degreasing stages typically require vacuum pump units, condensers, traps, connecting valves, and pressure detection units to maintain the process pressure of different vacuum units. Existing vacuum system control methods mostly rely on the pressure setpoints, stage operating status, and vacuum pump capacity of each vacuum unit for start-up, shutdown, frequency conversion, valve opening and closing, or supplementary pumping control, ensuring that the corresponding stages complete moisture removal, volatile component removal, or cryogenic treatment within a predetermined pressure range.

[0003] For refining lines with multiple vacuum units alternately entering and exiting vacuum phases, existing methods typically focus on maintaining the pressure of individual vacuum units and adjusting the vacuum pump load, failing to adequately utilize the phase transitions, volume differences, and pressure differentials between different vacuum units. Vacuum units exiting the phase are often handled with conventional venting or venting, while vacuum units entering the phase still primarily rely on individual vacuum pump pre-evacuation, easily leading to a disconnect between available pressure conditions and pre-evacuation load. Furthermore, different processes, oil batches, cleaning grades, and volatile matter interception states can affect the connectivity safety between vacuum units. Existing control methods lack a linkage judgment between energy consumption optimization and process isolation constraints, resulting in unnecessary supplementary evacuation loads on the vacuum pumps. Therefore, an energy consumption optimization control method and system for vacuum systems in vegetable oil refining are needed to address these issues. Summary of the Invention

[0004] To address the above problems, this invention provides the following technical solution: an energy consumption optimization and control method for a vacuum system used in vegetable oil refining, comprising: S1. Obtain the stage switching signal, cavity pressure, volume configuration, process configuration and controllable connection path status of each vacuum unit, and determine the residual negative pressure source vacuum unit in the vacuum exit stage and the target vacuum unit to be pre-evacuated in the vacuum entry stage based on the stage switching signal. S2. Based on the industrial vacuum mechanism model, according to the cavity pressure of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated and the corresponding volume in the volume configuration, a negative pressure capacity to be released is formed, which characterizes the residual negative pressure source vacuum unit as a substitute for the vacuum pump to receive gas before release. S3. When the preset process isolation conditions are met based on the state of the controllable connection path and the process configuration, the negative pressure capacity to be released is matched with the pre-evacuation requirement of the target vacuum unit to be pre-evacuated as determined by the process configuration to determine the negative pressure transfer permission and the target connection path. S4. Based on the negative pressure transfer permission, control the vacuum pump to reduce the suction output, and control the target connection path to make the residual negative pressure source vacuum unit and the target vacuum unit to be pre-pumped perform flow limiting and pressure equalization. S5. Determine the remaining pre-evacuation requirements based on the cavity pressure of the target vacuum unit to be pre-evacuated after flow limiting and pressure equalization and the process configuration, and generate vacuum pump replenishment control commands and connection path closure commands.

[0005] Furthermore, based on the industrial vacuum mechanism model, and according to the cavity pressures of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated, and the corresponding volumes in the volume configuration, a negative pressure capacity to be released, characterizing the residual negative pressure source vacuum unit's ability to replace the vacuum pump in receiving gas before release, is formed, including: The cavity pressure of the residual negative pressure source vacuum unit is compared with the allowable exit pressure determined by the process configuration to obtain the releasable pressure difference; The cavity pressure of the target vacuum unit to be pre-evacuated is compared with the pre-evacuation target pressure determined by the process configuration to obtain the evacuation pressure difference; Using the industrial vacuum mechanism model, the releasable pressure difference and the pressure difference to be pumped are converted into the same gas dimension according to the vacuum unit volume in the volume configuration, the controllable connection path resistance obtained from the controllable connection path state, and the condensation load reduction term determined by the process configuration, and the smaller value is taken to form the negative pressure capacity to be released.

[0006] Furthermore, the negative pressure capacity matching process includes: Based on the refining section, oil batch, cleaning level, preset material isolation rules, and valve position receipts in the controllable connection path status of the vacuum unit determined by the process configuration, vacuum unit pairs that do not meet the preset material isolation rules are eliminated. For the remaining vacuum units, the pre-evacuation requirement of the target vacuum unit to be pre-evacuated, determined by the process configuration, is converted into the pre-evacuation gas quantity, and the capacity utilization value is formed by the ratio of the negative pressure capacity to be released to the pre-evacuation gas quantity. Based on the path resistance obtained from the controllable connectivity path state, vacuum unit pairs that exceed the allowable resistance determined by the process configuration are eliminated, and the pair with the highest capacity utilization value among the remaining vacuum unit pairs is determined as the permissible pair. The controllable connectivity path corresponding to the license pair is determined as the target connectivity path, and the negative pressure transfer license is generated.

[0007] Furthermore, for any controllable connectivity path, the determination of the preset process isolation condition includes: Read the valve position receipt of the controllable connection path from the controllable connection path status, and confirm that the isolation valve is in a controllable state when the valve position receipt indicates that the isolation valve is adjustable; Read the oil batch, cleaning level and preset material isolation rules of the vacuum units at both ends of the controllable connection path from the process configuration, and confirm the material isolation permission when the oil batch and cleaning level of the vacuum units at both ends meet the preset material isolation rules; Read the operation receipt of at least one of the condenser and trap in the controllable connection path from the controllable connection path status, and confirm the volatile interception permission when the operation receipt meets the preset volatile interception state determined by the process configuration. Obtain the oxygen content sampling value of the target vacuum unit to be pre-evacuated, compare the oxygen content sampling value with the process allowable oxygen content determined by the process configuration, and confirm the low oxygen maintenance condition when the oxygen content sampling value does not exceed the process allowable oxygen content; When the controllable state, material isolation permission, volatile substance interception permission, and low oxygen maintenance conditions are all met, it is determined that the state of the controllable connection path meets the preset process isolation conditions.

[0008] Furthermore, the step of controlling the vacuum pump to reduce its suction output based on the negative pressure transfer permission, and controlling the target connection path to limit the flow and equalize the pressure between the residual negative pressure source vacuum unit and the target vacuum unit to be pre-pumped, includes: When generating the negative pressure transfer permission, a load reduction command is output to the vacuum pump, causing the vacuum pump's suction output to switch from maintaining suction output to compensating suction output. Read the valve position acknowledgment and path resistance of the target connection path from the controllable connection path status, and determine the valve opening change rate based on the valve position acknowledgment and path resistance; The opening of the connecting valve is adjusted according to the pressure difference between the cavity pressure of the residual negative pressure source vacuum unit and the cavity pressure of the target vacuum unit to be pre-evacuated, so that the gas enters the residual negative pressure source vacuum unit from the target vacuum unit to be pre-evacuated. The amount of gas transferred is calculated based on the pressure change in the cavity of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated, and the amount of gas transferred is subtracted from the negative pressure capacity to be released to obtain the current remaining value of the negative pressure capacity to be released. When any of the following termination conditions are met: the pressure difference between the two cavities is not greater than the equalization termination difference value determined by the process configuration, or the current remaining value of the negative pressure capacity to be released is not greater than the lower limit of the capacity determined by the process configuration, the target connection path is closed.

[0009] Furthermore, the step of determining the remaining pre-evacuation requirement based on the cavity pressure of the target vacuum unit to be pre-evacuated after flow limiting and pressure equalization and the process configuration, and generating a vacuum pump replenishment control command and a connection path closure command, includes: After limiting the flow and equalizing the pressure, the cavity pressure of the target vacuum unit to be pre-evacuated is read; The remaining pre-evacuation requirement is obtained by comparing the pressure in the cavity with the pre-evacuation target pressure determined by the process configuration. Obtain the operating status of the vacuum pump and determine the current available pumping capacity of the vacuum pump based on the operating status; The supplementary pumping output is determined based on the remaining pre-pumping requirement and the current available pumping capacity of the vacuum pump. Send a vacuum pump supplementary pumping control command containing the supplementary pumping output to the vacuum pump, and send a connection path closing command to the connection valve of the target connection path.

[0010] Furthermore, when there are multiple residual negative pressure source vacuum units and multiple target vacuum units to be pre-evacuated, the capacity of the negative pressure to be released is pre-occupied and scheduled, including: Establish a capacity record for each residual negative pressure source vacuum unit, and write the source unit identifier, the initial value of the negative pressure to be released, and the current remaining capacity into the capacity record; The remaining time of stage switching obtained from the stage switching signal is converted into time urgency, and the amount of pre-extraction required gas obtained from the pre-extraction requirement determined by the process configuration is converted into demand occupancy. The time urgency and the demand occupancy are weighted according to the preset weight determined by the process configuration to form a target priority. According to the target priority, select the source unit identifier from the capacity record with the current remaining capacity, and determine the occupancy amount allocated to the target vacuum unit to be pre-pumped based on the current remaining capacity in the capacity record and the amount of gas required for pre-pumping. Write the source unit identifier, the target unit identifier of the target vacuum unit to be pre-pumped, and the occupancy amount into the pre-occupancy record, and deduct the occupancy amount from the current remaining capacity in the capacity record. When the corresponding negative pressure transfer is completed, confirm that the occupied amount is the consumed amount; If either the corresponding negative pressure transfer is cancelled or the corresponding negative pressure transfer is not started within the permitted period obtained by the phase switching signal, the current remaining capacity in the capacity record corresponding to the source unit identifier is replenished according to the source unit identifier and occupancy in the pre-occupancy record.

[0011] Furthermore, the negative pressure capacity matching and current limiting pressure equalization processes also include the following abnormal handling: When the negative pressure transfer permission is not generated, it is prohibited to open the controllable connection path that has not obtained the negative pressure transfer permission, and the target vacuum unit to be pre-evacuated is switched to direct pre-evacuation by the vacuum pump; When the preset process isolation condition fails during the current limiting and pressure equalization process, the already opened target connection path is closed, and the target vacuum unit to be pre-evacuated is switched to direct pre-evacuation by the vacuum pump. When the residual negative pressure source vacuum unit still has a vacuum exit request obtained from the stage switching signal, there is no negative pressure transfer permission, the residual negative pressure source vacuum unit is within the allowable pressure holding period determined by the stage switching signal and the subsequent target vacuum unit to be pre-evacuated is identified by the stage switching signal, the residual negative pressure source vacuum unit is kept in isolation and pressure holding. When the residual negative pressure source vacuum unit still has a vacuum exit request obtained from the stage switching signal, there is no negative pressure transfer permission, and the exit venting condition is met, an inert gas controlled venting command is output to the residual negative pressure source vacuum unit. The exit venting condition includes at least one of the following: the residual negative pressure source vacuum unit is not in the allowable pressure holding period determined by the stage switching signal, and the stage switching signal has not identified any subsequent target vacuum unit to be pre-evacuated. Record the reasons for matching failures corresponding to the failure of the preset process isolation conditions, and update the availability status of the corresponding controllable connectivity path based on the recorded reasons.

[0012] The present invention also provides an energy consumption optimization control system for a vacuum system for vegetable oil refining, for implementing the above method, comprising: The source target identification module is used to acquire the stage switching signal, cavity pressure, volume configuration, process configuration and controllable connection path status of each vacuum unit, and to determine the residual negative pressure source vacuum unit in the vacuum exit stage and the target vacuum unit to be pre-evacuated in the vacuum entry stage based on the stage switching signal. The negative pressure capacity forming module is used to form a negative pressure capacity to be released, which characterizes the residual negative pressure source vacuum unit as a substitute for the vacuum pump to receive gas before release, based on the industrial vacuum mechanism model, according to the cavity pressure of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated, and the corresponding volume in the volume configuration. The matching permission module is used to perform negative pressure capacity matching processing on the negative pressure capacity to be released and the pre-evacuation requirement of the target vacuum unit to be pre-evacuated as determined by the process configuration when the preset process isolation conditions are met based on the state of the controllable connection path and the process configuration, thereby determining the negative pressure transfer permission and the target connection path; The current limiting and pressure equalization control module is used to control the vacuum pump to reduce the suction output according to the negative pressure transfer permission, and to control the target connection path to make the residual negative pressure source vacuum unit and the target vacuum unit to be pre-pumped perform current limiting and pressure equalization. The supplementary pumping instruction generation module is used to determine the remaining pre-pumping requirements based on the cavity pressure of the target vacuum unit to be pre-pumped after flow limiting and pressure equalization and the process configuration, and to generate vacuum pump supplementary pumping control instructions and connection path closure instructions.

[0013] Compared with the prior art, the present invention has the following beneficial effects: By identifying the residual negative pressure source vacuum unit and the target vacuum unit to be pre-pumped using the stage switching signal, and forming the negative pressure capacity to be released based on the industrial vacuum mechanism model, cavity pressure and volume configuration, the vacuum unit in the exit stage has a measurable and matchable basis for negative pressure utilization before release. After matching the negative pressure capacity to be released with the pre-pumping requirements of the target vacuum unit, the target connection path is controlled to limit flow and equalize pressure and reduce the vacuum pump output, so that the pressure conditions that originally disappeared with the rupture or release process can participate in the pre-pumping process of the target vacuum unit, thereby reducing the situation where the target vacuum unit relies entirely on the vacuum pump for pre-pumping.

[0014] By using the controllable connectivity path status and process configuration together to determine the preset process isolation conditions, and combining valve position receipts, oil batches, cleaning levels, volatile matter interception status, and oxygen content sampling values ​​to limit negative pressure transfer permissions, negative pressure transfer is only performed between vacuum unit pairs that meet the connectivity safety conditions. This reduces the possibility of connectivity paths that do not meet material isolation or volatile matter interception requirements being opened. At the same time, multiple residual negative pressure source vacuum units are scheduled through capacity recording, pre-occupancy recording, occupancy deduction, and cancellation of replenishment. After flow limiting and pressure equalization, replenishment control commands are generated based on the remaining pre-evacuation demand and vacuum pump operating status. This ensures that the vacuum pump replenishment amount corresponds to the actual remaining demand after negative pressure transfer, thereby reducing duplicate capacity occupancy, invalid transfers, and unnecessary replenishment command outputs. Attached Figure Description

[0015] Figure 1 A flowchart illustrating the energy consumption optimization and control method for a vacuum system used in vegetable oil refining provided by this invention. Figure 2 The flowchart of negative pressure capacity matching and current limiting and pressure equalization control provided by the present invention; Figure 3 The structure diagram of the energy consumption optimization control system for the vacuum system for vegetable oil refining provided by the present invention; Figure 4 This is a schematic diagram of negative pressure capacity matching and current limiting pressure equalization provided by the present invention. Detailed Implementation

[0016] 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, and 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.

[0017] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Please see Figure 1 and Figure 2 , Figure 1 A flowchart illustrating the energy consumption optimization and control method for a vacuum system used in vegetable oil refining provided by this invention. Figure 2 This invention provides a flowchart for negative pressure capacity matching and current limiting pressure equalization control. The invention also provides an energy consumption optimization control method for a vacuum system used in vegetable oil refining, comprising: S1. Obtain the stage switching signal, cavity pressure, volume configuration, process configuration and controllable connection path status of each vacuum unit, and determine the residual negative pressure source vacuum unit in the vacuum exit stage and the target vacuum unit to be pre-evacuated in the vacuum entry stage based on the stage switching signal. Specifically, this invention is executed by a controller in a vegetable oil refining production line. The controller is communicatively connected to pressure sensors, oxygen content samplers, connecting valves, isolation valves, condensers, traps, and vacuum pump sets in each vacuum unit. A vacuum unit is a process chamber in the vegetable oil refining process that requires the establishment or exit of a vacuum environment, including vacuum chambers in deacidification, deodorization, drying, dewaxing, or similar refining sections. The controller reads stage switching signals according to a fixed control cycle. These signals include at least the vacuum unit identifier, current process stage, vacuum exit request, vacuum entry request, remaining stage switching time, and allowable pressure holding period. The chamber pressure is the absolute pressure sample value of the corresponding vacuum unit. The volume configuration includes at least the vacuum unit volume, the connecting path volume, and the correspondence between the two vacuum units. The process configuration includes at least the allowable exit pressure, pre-evacuation target pressure, the refining section to which the vacuum unit belongs, the oil batch, the cleaning grade, preset material isolation rules, allowable resistance, allowable oxygen content, condensation load reduction item, equalization termination difference, and lower capacity limit. The status of a controllable connected path includes at least the path identifier, the vacuum unit identifiers at both ends of the path, the valve position acknowledgment, the path resistance, the condenser operation acknowledgment, the trap operation acknowledgment, and the current availability status of the path.

[0019] When a vacuum unit's stage switching signal indicates that the unit has completed its current refining stage and is about to exit the vacuum environment, the controller marks that unit as a residual negative pressure source vacuum unit. When another vacuum unit's stage switching signal indicates that it is about to enter a refining stage requiring pre-vacuuming, the controller marks that unit as a target vacuum unit to be pre-vacuumed. These two types of markings are written into the stage switching record, which uses the vacuum unit identifier and control cycle number as indexes and serves as input for generating the negative pressure capacity to be released and performing negative pressure capacity matching processing.

[0020] S2. Based on the industrial vacuum mechanism model, according to the cavity pressure of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated and the corresponding volume in the volume configuration, a negative pressure capacity to be released is formed, which characterizes the residual negative pressure source vacuum unit as a substitute for the vacuum pump to receive gas before release. Specifically, the industrial vacuum mechanism model is used to convert pressure difference, volume, path resistance, pressure equalization accessibility, and condensation load into a unified gas dimension. The controller records the cavity pressure of the residual negative pressure source vacuum unit as... The allowable exit pressure determined by the process configuration is denoted as .when Greater than At that time, the pressure difference that can be released is ;when Not greater than At this time, the pressure difference can be released and set to zero. The controller records the cavity pressure of the target vacuum unit to be pre-evacuated as... The pre-extraction target pressure determined by the process configuration is denoted as... .when Greater than At that time, the pressure difference to be pumped is ;when Not greater than At that time, the pressure difference to be pumped is set to zero.

[0021] Furthermore, in one embodiment of the present invention, the step of forming a negative pressure capacity to be released, characterizing the residual negative pressure source vacuum unit as a substitute for the vacuum pump to receive gas before release, based on the industrial vacuum mechanism model, according to the cavity pressure of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated, and the corresponding volume in the volume configuration, includes: The cavity pressure of the residual negative pressure source vacuum unit is compared with the allowable exit pressure determined by the process configuration to obtain the releasable pressure difference; The cavity pressure of the target vacuum unit to be pre-evacuated is compared with the pre-evacuation target pressure determined by the process configuration to obtain the evacuation pressure difference; Using the industrial vacuum mechanism model, the releasable pressure difference and the pressure difference to be pumped are converted into the same gas dimension according to the vacuum unit volume in the volume configuration, the controllable connection path resistance obtained from the controllable connection path state, and the condensation load reduction term determined by the process configuration, and the smaller value is taken to form the negative pressure capacity to be released.

[0022] Specifically, the controller first determines the initial acceptable gas quantity for the source unit itself:

[0023] in, The amount of gas that the residual negative pressure source vacuum unit can accept before reaching the allowable exit pressure; This represents the volume of the residual negative pressure source vacuum unit; it indicates that the difference is taken when it is greater than zero and zero when it is not greater than zero. The source-side gas compressibility coefficient; It is the gas constant; This refers to the source-side gas temperature. The controller establishes a source unit capacity record using the source unit identifier and control cycle number, and writes the initial value of the negative pressure capacity to be released into the source unit capacity record. Current remaining capacity Reserved capacity and consumed capacity. Current remaining capacity at the start of the control cycle. Depend on The amount obtained is obtained by deducting the pre-occupied amount that has not yet been settled and the amount occupied during execution; the completed records that have already been reflected in the current cavity pressure by pressure sampling will not be deducted again.

[0024] The pre-evacuation gas requirement for the target unit is determined by the following formula:

[0025] in, The required amount of gas for pre-evacuation of the target vacuum unit; The volume of the vacuum unit on the target side; This means that the difference is taken when the value is greater than zero, and zero is taken when the value is not greater than zero. The target side gas compressibility coefficient; The target gas temperature. The controller also generates a path effectiveness coefficient based on the state of the controllable connected path. The effective path coefficient is not a direct summation of unit path resistances, but a dimensionless coefficient read by the controller from a pre-calibrated path throughput capacity table based on path identifiers, valve opening ranges, pressure difference ranges at both ends, and permissible connection time determined by stage switching signals. When a corresponding calibration record is missing, the source-target pair is marked as having insufficient path throughput capacity.

[0026] Condensation load reduction item The value is a dimensionless coefficient greater than zero and not greater than one. The controller reads this value from a pre-calibrated condensation load reduction table based on the target unit's section, current temperature, volatile load, condenser operating status, and trap pressure difference. This reduction item represents the impact of the condensation or trapping process on changes in gas phase volume and stable pressure equalization processes. When the condenser is shut down, the trap pressure difference exceeds the limit, or the corresponding section lacks calibration records, the source-target pair is marked as not meeting the condensation load condition.

[0027] The controller also calculates the attainability of equal pressure under passive connection at both ends. When both ends are approximately isothermal and the compressibility coefficients are of the same calibration diameter, the equal pressure is determined according to the following formula:

[0028] The amount of gas required to equalize pressure is obtained from the equilibrium pressure:

[0029] in, This represents the maximum achievable amount of gas that can enter the residual negative pressure source vacuum unit from the target vacuum unit to be pre-pumped under passive interconnection conditions without relying on additional vacuum pumping. The available amount of the current source-target pairing is determined by the following formula:

[0030] in, The available pairing quantity for the current source target pairing is determined after considering the current remaining capacity of the source unit, path throughput, pressure equalization accessibility, and condensation load, and satisfies the following conditions. The negative pressure capacity to be released is determined by the following formula:

[0031] in, This represents the negative pressure capacity to be released under the current source-target pairing. This capacity is not a source capacity record generated separately for each target unit, but rather a permissible calculation within the candidate pairing record; the source unit itself is still maintained through the same source unit capacity record. and This avoids the same residual negative pressure source vacuum unit being repeatedly pre-occupied when facing multiple target vacuum units to be pre-pumped.

[0032] S3. When the preset process isolation conditions are met based on the state of the controllable connection path and the process configuration, the negative pressure capacity to be released is matched with the pre-evacuation requirement of the target vacuum unit to be pre-evacuated as determined by the process configuration to determine the negative pressure transfer permission and the target connection path. Specifically, after a candidate pairing record is formed, the controller reads the status of the controllable connectivity path and the process configuration corresponding to that pairing. The controller only allows the candidate pairing to enter the negative pressure capacity matching process when the requirements for valve position acknowledgment, oil batch, cleaning level, volatile matter interception status, and oxygen content are all met. The output of the negative pressure capacity matching process includes the permitted pairing record, negative pressure transfer permission, and the target connectivity path. The candidate pairing record must at least include the source unit identifier, target unit identifier, path identifier, and available pairing quantity. The negative pressure capacity to be released Pre-extraction required gas volume Capacity utilization value, process isolation status, and matching time.

[0033] Furthermore, in one embodiment of the present invention, the negative pressure capacity matching process includes: Based on the refining section, oil batch, cleaning level, preset material isolation rules, and valve position receipts in the controllable connection path status of the vacuum unit determined by the process configuration, vacuum unit pairs that do not meet the preset material isolation rules are eliminated. For the remaining vacuum units, the pre-evacuation requirement of the target vacuum unit to be pre-evacuated, determined by the process configuration, is converted into the pre-evacuation gas quantity, and the capacity utilization value is formed by the ratio of the negative pressure capacity to be released to the pre-evacuation gas quantity. Based on the path resistance obtained from the controllable connectivity path state, vacuum unit pairs that exceed the allowable resistance determined by the process configuration are eliminated, and the pair with the highest capacity utilization value among the remaining vacuum unit pairs is determined as the permissible pair. The controllable connectivity path corresponding to the license pair is determined as the target connectivity path, and the negative pressure transfer license is generated.

[0034] Specifically, the controller first establishes a material isolation judgment key based on the refining section, oil batch, cleaning level, and preset material isolation rules of the vacuum unit. The material isolation judgment key consists of the source unit identifier, target unit identifier, oil batch, cleaning level, and section identifier. If the oil batches at both the source and target ends do not belong to the batch range allowed for shared negative pressure transfer, or if the cleaning level is lower than the preset material isolation rule requirements, the controller marks the candidate pairing as material isolation unmet and removes it from the remaining vacuum unit pairings. If the valve position acknowledgment indicates that the isolation valve is not adjustable, the path is not fully closed, or the acknowledgment has exceeded the preset waiting period and has not returned, the candidate pairing is marked as valve position acknowledgment unmet.

[0035] The capacity utilization value is calculated using the following formula:

[0036] in, The negative pressure capacity to be released is obtained by taking the smaller value between the available amount of gas for pairing and the amount of gas required for pre-evacuation. The available quantity of the paired source is determined after considering the current remaining capacity of the source unit, path throughput, equalization accessibility, and condensation load. When When the value is zero, the pairing is not included in the sorting. The capacity utilization value indicates the degree to which the pre-sampling demand of the current target unit utilizes the available negative pressure capacity under the source target pairing; the higher the capacity utilization value, the less unused capacity the source unit has in this pairing. If multiple candidate pairings have the same capacity utilization value, the controller sorts them in the following order: target priority with lower path resistance, shorter remaining phase switching time, higher target priority, and stable unit identifier, to form a determined permitted pairing.

[0037] Furthermore, in one embodiment of the present invention, the determination of the preset process isolation condition for any controllable connectivity path includes: Read the valve position receipt of the controllable connection path from the controllable connection path status, and confirm that the isolation valve is in a controllable state when the valve position receipt indicates that the isolation valve is adjustable; Read the oil batch, cleaning level and preset material isolation rules of the vacuum units at both ends of the controllable connection path from the process configuration, and confirm the material isolation permission when the oil batch and cleaning level of the vacuum units at both ends meet the preset material isolation rules; Read the operation receipt of at least one of the condenser and trap in the controllable connection path from the controllable connection path status, and confirm the volatile interception permission when the operation receipt meets the preset volatile interception state determined by the process configuration. Obtain the oxygen content sampling value of the target vacuum unit to be pre-evacuated, compare the oxygen content sampling value with the process allowable oxygen content determined by the process configuration, and confirm the low oxygen maintenance condition when the oxygen content sampling value does not exceed the process allowable oxygen content; When the controllable state, material isolation permission, volatile substance interception permission, and low oxygen maintenance conditions are all met, it is determined that the state of the controllable connection path meets the preset process isolation conditions.

[0038] Specifically, the controller breaks down the preset process isolation conditions into four Boolean fields: controllable state, material isolation permission, volatile matter interception permission, and low-oxygen maintenance condition. When all four fields are true, candidate pairings are sorted by capacity utilization value; when any field is false, the candidate pairing is eliminated and the reason for failure is recorded. Oxygen content sampling values ​​are provided by the oxygen content sampler of the target vacuum unit to be pre-evacuated. If the sampling value exceeds the process's allowable oxygen content, the controller prohibits opening the corresponding target connection path to prevent negative pressure transfer from disrupting the low-oxygen environment in vegetable oil refining. Volatile matter interception permission is determined by the condenser or trap operation receipt, used to prevent volatile components between the two vacuum units from entering the mismatched process section without being intercepted.

[0039] S4. Based on the negative pressure transfer permission, control the vacuum pump to reduce the suction output, and control the target connection path to make the residual negative pressure source vacuum unit and the target vacuum unit to be pre-pumped perform flow limiting and pressure equalization. Specifically, after the negative pressure transfer permission is generated, the controller does not immediately pre-pump the target unit with the full capacity of the vacuum pump. Instead, it first sends a load reduction command to the vacuum pump group, causing the pump group to switch from maintaining pump output to compensating pump output. The compensating pump output is used to maintain the system safety boundary and compensate for pressure deviations caused by condensation, leakage, or disturbances, and does not undertake the full pre-pumping requirements of the target unit. Subsequently, the controller controls the connecting valve to open at a limited speed according to the target connection path, allowing the gas in the target vacuum unit to be pre-pumped to enter the residual negative pressure source vacuum unit under the action of the pressure difference.

[0040] Furthermore, in one embodiment of the present invention, the step of controlling the vacuum pump to reduce its suction output according to the negative pressure transfer permission, and controlling the target connection path to limit the flow and equalize the pressure between the residual negative pressure source vacuum unit and the target vacuum unit to be pre-pumped, includes: When generating the negative pressure transfer permission, a load reduction command is output to the vacuum pump, causing the vacuum pump's suction output to switch from maintaining suction output to compensating suction output. Read the valve position acknowledgment and path resistance of the target connection path from the controllable connection path status, and determine the valve opening change rate based on the valve position acknowledgment and path resistance; The opening of the connecting valve is adjusted according to the pressure difference between the cavity pressure of the residual negative pressure source vacuum unit and the cavity pressure of the target vacuum unit to be pre-evacuated, so that the gas enters the residual negative pressure source vacuum unit from the target vacuum unit to be pre-evacuated. The amount of gas transferred is calculated based on the pressure change in the cavity of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated, and the amount of gas transferred is subtracted from the negative pressure capacity to be released to obtain the current remaining value of the negative pressure capacity to be released. When any of the following termination conditions are met: the pressure difference between the two cavities is not greater than the equalization termination difference value determined by the process configuration, or the current remaining value of the negative pressure capacity to be released is not greater than the lower limit of the capacity determined by the process configuration, the target connection path is closed.

[0041] Specifically, the controller converts the path resistance of the target connectivity path into normalized path resistance. The valve position confirmation confirms that the connecting valve is in an adjustable state. The rate of change of the connecting valve opening is determined by the following formula:

[0042] in, The rate of change of the valve opening. The maximum permissible rate of change of valve opening, determined by the configuration of the valve actuator. To calibrate the gain of the valve, This is a dimensionless path resistance. The controller follows... The opening degree of the connecting valve is increased in stages, and the pressure of the two end chambers, valve position acknowledgment, and vacuum pump compensation suction output are read in each sampling cycle.

[0043] During the flow restriction and pressure equalization period, the actual amount of gas transferred is calculated using the source-side pressure rise as the primary calculation quantity:

[0044] in, This refers to the source-side cavity pressure after flow limiting and pressure equalization, or at the end of the current sampling period. When the target-side pressure drop is used for verification, the controller deducts the concurrent vacuum pump pumping volume and condensation or trapping correction amounts.

[0045] in, The cavity pressure at the end of the current sampling period on the target side. This refers to the pumping volume of the vacuum pump during the same period. This is a correction value for condensation or trapping. If both the source-side pressure sampling and valve position acknowledgment are reliable, the controller will... As the actual amount of gas transferred; if there are short-term fluctuations in the source-side sampling and the target-side verification value is reliable, the controller takes... and The value should not exceed the smaller of the current remaining value of the negative pressure capacity to be released, and the verification status should be written to the transfer record. The current remaining value of the negative pressure capacity to be released is determined by... The actual amount of gas transferred is deducted. Except that the pressure difference between the two chambers is not greater than the pressure equalization termination difference and the current remaining value of the negative pressure to be released is not greater than the lower limit of the capacity, when the chamber pressure of the target vacuum unit to be pre-evacuated reaches the pre-evacuation target pressure, the controller also closes the target connection path and ends this flow-limiting pressure equalization.

[0046] S5. Determine the remaining pre-evacuation requirements based on the cavity pressure of the target vacuum unit to be pre-evacuated after flow limiting and pressure equalization and the process configuration, and generate vacuum pump replenishment control commands and connection path closure commands.

[0047] Specifically, after the target connection path is closed, the controller reads the cavity pressure of the target vacuum unit to be pre-pumped and compares it with the pre-pumping target pressure in the process configuration. If the flow limiting and pressure equalization have brought the target unit pressure to the pre-pumping target pressure, the remaining pre-pumping requirement is zero, the controller keeps the connection path closed and records the completion of this negative pressure transfer. If the target unit pressure is still higher than the pre-pumping target pressure, the controller converts the difference between the two into the remaining pre-pumping requirement based on the target unit volume, reads the vacuum pump operating status, and generates a vacuum pump supplementary pumping control command.

[0048] Furthermore, in one embodiment of the present invention, the step of determining the remaining pre-evacuation requirement based on the cavity pressure of the target vacuum unit to be pre-evacuated after current limiting and pressure equalization and the process configuration, and generating a vacuum pump replenishment control command and a connection path closure command, includes: After limiting the flow and equalizing the pressure, the cavity pressure of the target vacuum unit to be pre-evacuated is read; The remaining pre-evacuation requirement is obtained by comparing the pressure in the cavity with the pre-evacuation target pressure determined by the process configuration. Obtain the operating status of the vacuum pump and determine the current available pumping capacity of the vacuum pump based on the operating status; The supplementary pumping output is determined based on the remaining pre-pumping requirement and the current available pumping capacity of the vacuum pump. Send a vacuum pump supplementary pumping control command containing the supplementary pumping output to the vacuum pump, and send a connection path closing command to the connection valve of the target connection path.

[0049] Specifically, the vacuum pump operating status includes pump unit operation, pump unit shutdown, current pump failure, standby pump availability, frequency adjustable, frequency non-adjustable, current pumping capacity, and maximum allowable pumping capacity. If the pump unit is operating and the frequency is adjustable, the controller calculates the supplementary pumping output based on the remaining pre-pumping demand and allowable supplementary pumping time, and converts the supplementary pumping output into pump frequency or pump unit start / stop count. If the pump unit is operational but the frequency is non-adjustable, the controller maintains the current pumping output and performs direct pre-pumping, monitoring the target pressure with a shorter sampling period. If the current pump fails but the standby pump is available, the controller switches to the standby pump to perform direct pre-pumping. If the pump unit has no available pumping capacity, the controller keeps the target connection path closed, outputs an alarm indicating no available pumping capacity, and prohibits opening unauthorized connection paths.

[0050] Furthermore, in one embodiment of the present invention, when there are multiple residual negative pressure source vacuum units and multiple target vacuum units to be pre-evacuated, the pre-occupancy scheduling of the negative pressure capacity to be released includes: Establish a capacity record for each residual negative pressure source vacuum unit, and write the source unit identifier, the initial value of the negative pressure to be released, and the current remaining capacity into the capacity record; The remaining time of stage switching obtained from the stage switching signal is converted into time urgency, and the amount of pre-extraction required gas obtained from the pre-extraction requirement determined by the process configuration is converted into demand occupancy. The time urgency and the demand occupancy are weighted according to the preset weight determined by the process configuration to form a target priority. According to the target priority, select the source unit identifier from the capacity record with the current remaining capacity, and determine the occupancy amount allocated to the target vacuum unit to be pre-pumped based on the current remaining capacity in the capacity record and the amount of gas required for pre-pumping. Write the source unit identifier, the target unit identifier of the target vacuum unit to be pre-pumped, and the occupancy amount into the pre-occupancy record, and deduct the occupancy amount from the current remaining capacity in the capacity record. When the corresponding negative pressure transfer is completed, confirm that the occupied amount is the consumed amount; If either the corresponding negative pressure transfer is cancelled or the corresponding negative pressure transfer is not started within the permitted period obtained by the phase switching signal, the current remaining capacity in the capacity record corresponding to the source unit identifier is replenished according to the source unit identifier and occupancy in the pre-occupancy record.

[0051] Specifically, capacity records are established based on residual negative pressure source vacuum units. The record keys include the source unit identifier and control cycle number. The capacity record includes the initial value of the negative pressure to be released, the current remaining capacity, the pre-allocated capacity, and the consumed capacity. The candidate target unit identifier is not used as the record key for capacity records; instead, it is written into the candidate pairing record and the pre-allocation record. This ensures that the same source unit shares the same current remaining capacity when facing different target units, avoiding duplicate pre-allocation. The candidate pairing record includes the source unit identifier, target unit identifier, path identifier, available pairing quantity, negative pressure to be released capacity, capacity utilization value, and process isolation status. The pre-allocation record includes the source unit identifier, target unit identifier, path identifier, occupancy quantity, permitted time period, start-up time, completion status, and replenishment mark.

[0052] The controller first calculates the target priority for multiple target vacuum units to be pre-pumped. The target priority is formed by a weighted average of time urgency and demand occupancy. Time urgency increases as the remaining time for stage switching decreases, and demand occupancy increases as the amount of gas required for pre-pumping increases. After the target priority is determined, the controller selects source units for the target units in order of priority. For the current target unit, the controller only calculates the capacity utilization value and ranks the candidate source units that have current remaining capacity and meet the process isolation conditions. The source unit with the highest capacity utilization value is selected and written into the pre-occupancy record, and the occupancy is deducted from the current remaining capacity of the source unit's capacity record. This sequential pre-occupancy method is consistent with the capacity record deduction order to avoid inconsistencies in the algorithm results caused by comparing mutually exclusive combinations simultaneously.

[0053] When negative pressure transfer is completed normally, the controller confirms the occupied amount in the pre-allocation record as the consumed amount and updates the capacity record status to complete. If negative pressure transfer is not started or is canceled, the controller replenishes the current remaining capacity based on the source unit identifier and occupied amount in the pre-allocation record. If negative pressure transfer is stopped due to isolation condition failure, valve position abnormality, or pump alarm after partial execution, the controller first confirms the consumed amount based on the actual amount of gas transferred, and then writes the difference between the occupied amount and the actual amount of gas transferred into the replenishment field; this replenishment field is merged into the current remaining capacity of the corresponding source unit identifier, and the replenishment time and reason are written to prevent loss of book capacity.

[0054] Furthermore, in one embodiment of the present invention, the following abnormal handling is also included in the negative pressure capacity matching process and current limiting and pressure equalization process: When the negative pressure transfer permission is not generated, it is prohibited to open the controllable connection path that has not obtained the negative pressure transfer permission, and the target vacuum unit to be pre-evacuated is switched to direct pre-evacuation by the vacuum pump; When the preset process isolation condition fails during the current limiting and pressure equalization process, the already opened target connection path is closed, and the target vacuum unit to be pre-evacuated is switched to direct pre-evacuation by the vacuum pump. When the residual negative pressure source vacuum unit still has a vacuum exit request obtained from the stage switching signal, there is no negative pressure transfer permission, the residual negative pressure source vacuum unit is within the allowable pressure holding period determined by the stage switching signal and the subsequent target vacuum unit to be pre-evacuated is identified by the stage switching signal, the residual negative pressure source vacuum unit is kept in isolation and pressure holding. When the residual negative pressure source vacuum unit still has a vacuum exit request obtained from the stage switching signal, there is no negative pressure transfer permission, and the exit venting condition is met, an inert gas controlled venting command is output to the residual negative pressure source vacuum unit. The exit venting condition includes at least one of the following: the residual negative pressure source vacuum unit is not in the allowable pressure holding period determined by the stage switching signal, and the stage switching signal has not identified any subsequent target vacuum unit to be pre-evacuated. Record the reasons for matching failures corresponding to the failure of the preset process isolation conditions, and update the availability status of the corresponding controllable connectivity path based on the recorded reasons.

[0055] Specifically, when no negative pressure transfer permission is generated, the controller prohibits opening all unpermitted connection paths and reads the vacuum pump operating status. Direct pre-evacuation is performed by the currently available vacuum pump or standby pump; if the pump set has no available suction capacity, the target connection path remains closed and an alarm is output. During the flow-limiting and pressure-equalizing process, if any of the material isolation permission, volatile matter interception permission, low oxygen maintenance condition, or valve position controllability fails, the controller immediately sends a closure command to the target connection path and closes any opened connection valves to the isolation position. If the residual negative pressure source vacuum unit is within the allowed pressure-holding period and the stage switching signal identifies a subsequent target vacuum unit to be pre-evacuated, the controller maintains the isolation and pressure holding of that source unit to allow for the continued formation of the negative pressure capacity to be released; if it is outside the allowed pressure-holding period or no subsequent target is identified, the controller uses controlled venting with inert gas to prevent air from directly entering the high-temperature oil-related vacuum chambers.

[0056] The availability status record of a controllable connectivity path includes a hardware availability field and a current pairing permission field. Valve failure, abnormal receipt, condenser failure, or trap failure is written to the hardware availability field, making the corresponding path unavailable until the failure is resolved. Oil batch mismatch, insufficient cleaning level, excessive oxygen content, or no target unit currently is written to the current pairing permission field, affecting only the current source-target pairing and not permanently reducing the hardware availability status of the path.

[0057] Please see Figure 4 , Figure 4 This is a schematic diagram of negative pressure capacity matching and current limiting pressure equalization provided by the present invention. Figure 4 The relationship between the residual negative pressure source vacuum unit, the target vacuum unit to be pre-evacuated, the target connection path, and the direction of flow limiting and pressure equalization is shown. Figure 4 The source-side value is the releasable pressure difference converted to a value. In the illustrated embodiment, the current remaining capacity of the source unit, path throughput capacity, pressure equalization reachability, and condensation load do not create a limitation lower than the releasable pressure difference converted to a value. Therefore, the releasable pressure difference converted to a value simultaneously constitutes the available quantity for the corresponding candidate pairing. The target-side value is the amount of gas required for pre-pumping. The controller takes the smaller value between the available quantity for pairing and the amount of gas required for pre-pumping to form the negative pressure capacity to be released under the current source target pairing, and uses this negative pressure capacity to be released as the calculation basis for negative pressure transfer permission and pre-occupancy scheduling. The flow-limiting and pressure equalization arrows indicate that the gas enters the residual negative pressure source vacuum unit from the target vacuum unit to be pre-pumped, and the target connection path indicates the controllable connection path after being permitted by the preset process isolation conditions.

[0058] In one embodiment, the controller reads two source units and two target units within the same control cycle. The available pairing quantity for source unit identifier one is 80, and for source unit identifier two it is 45. The pre-evacuation gas demand for target unit identifier one is 55, and for target unit identifier two it is 70. The remaining time for the stage switch of target unit identifier one is shorter than that of target unit identifier two, indicating a higher target priority for target unit identifier one. The controller processes target unit identifier one first. The combined negative pressure capacity to be released for source unit identifier one and target unit identifier one is 55, with a capacity utilization of 55 / 80, or 68.75%. The combined negative pressure capacity to be released for source unit identifier two and target unit identifier one is 45, with a capacity utilization of 45 / 45, or 100%. Therefore, source unit identifier two and target unit identifier one are selected as the permitted pairing. After the pre-occupancy is completed, the controller processes target unit identifier two, forming a negative pressure capacity of 70 to be released between the remaining source unit identifier one and target unit identifier two. The capacity utilization value is 70 / 80, or 87.5%, and a corresponding negative pressure transfer permit is generated. This example uses sequential pre-occupancy and does not use global combined sum comparison, thus... Figure 4 The capacity record and matching algorithm remain consistent.

[0059] Please see Figure 3 , Figure 3 This invention provides a structural diagram of an energy consumption optimization control system for a vacuum system used in vegetable oil refining. The invention also provides an energy consumption optimization control system for a vacuum system used in vegetable oil refining, for implementing the above method, comprising the following interconnected modules: The source target identification module is used to acquire the stage switching signal, cavity pressure, volume configuration, process configuration and controllable connection path status of each vacuum unit, and to determine the residual negative pressure source vacuum unit in the vacuum exit stage and the target vacuum unit to be pre-evacuated in the vacuum entry stage based on the stage switching signal. The negative pressure capacity forming module is used to form a negative pressure capacity to be released, which characterizes the residual negative pressure source vacuum unit as a substitute for the vacuum pump to receive gas before release, based on the industrial vacuum mechanism model, according to the cavity pressure of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated, and the corresponding volume in the volume configuration. The matching permission module is used to perform negative pressure capacity matching processing on the negative pressure capacity to be released and the pre-evacuation requirement of the target vacuum unit to be pre-evacuated as determined by the process configuration when the preset process isolation conditions are met based on the state of the controllable connection path and the process configuration, thereby determining the negative pressure transfer permission and the target connection path; The current limiting and pressure equalization control module is used to control the vacuum pump to reduce the suction output according to the negative pressure transfer permission, and to control the target connection path to make the residual negative pressure source vacuum unit and the target vacuum unit to be pre-pumped perform current limiting and pressure equalization. The supplementary pumping instruction generation module is used to determine the remaining pre-pumping requirements based on the cavity pressure of the target vacuum unit to be pre-pumped after flow limiting and pressure equalization and the process configuration, and to generate vacuum pump supplementary pumping control instructions and connection path closure instructions.

[0060] Specifically, the source target identification module reads the stage switching signal from the production line control system, the chamber pressure from the pressure sampling interface, the volume configuration and process configuration from the configuration storage area, and the controllable connection path status from the valve and interception device interface. The source target identification module writes the identified residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated into the stage switching record and sends it to the negative pressure capacity forming module. The negative pressure capacity forming module reads the stage switching record, chamber pressure, volume configuration, path resistance, pressure equalization reachability, and condensation load reduction item, forms the negative pressure capacity to be released according to the industrial vacuum mechanism model, and sends the candidate pairing record to the matching authorization module. The matching authorization module reads the candidate pairing record, process configuration, and controllable connection path status, performs preset process isolation condition judgment and capacity utilization value sorting, and outputs the negative pressure transfer authorization and the target connection path. After receiving the negative pressure transfer authorization, the flow limiting and pressure equalization control module outputs a load reduction command to the vacuum pump, an opening control command to the connecting valve of the target connection path, and continuously reads back the pressure and valve position. After the pressure equalization and flow control are completed, the supplementary pumping command generation module reads the target unit cavity pressure and vacuum pump operating status, calculates the remaining pre-pumping demand and supplementary pumping output, sends a supplementary pumping control command to the vacuum pump, and sends a connection path closure command to the connecting valve. These modules are deployed in the same industrial controller or in an edge control unit between the production line controller and the vacuum pump frequency converter. Records and commands are transmitted between modules via a control bus, industrial Ethernet, or internal data bus.

[0061] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0062] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for optimizing and controlling energy consumption in a vacuum system for vegetable oil refining, characterized in that, include: S1. Obtain the stage switching signal, cavity pressure, volume configuration, process configuration and controllable connection path status of each vacuum unit, and determine the residual negative pressure source vacuum unit in the vacuum exit stage and the target vacuum unit to be pre-evacuated in the vacuum entry stage based on the stage switching signal. S2. Based on the industrial vacuum mechanism model, according to the cavity pressure of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated and the corresponding volume in the volume configuration, a negative pressure capacity to be released is formed, which characterizes the residual negative pressure source vacuum unit as a substitute for the vacuum pump to receive gas before release. S3. When the preset process isolation conditions are met based on the state of the controllable connection path and the process configuration, the negative pressure capacity to be released is matched with the pre-evacuation requirement of the target vacuum unit to be pre-evacuated as determined by the process configuration to determine the negative pressure transfer permission and the target connection path. S4. Based on the negative pressure transfer permission, control the vacuum pump to reduce the suction output, and control the target connection path to make the residual negative pressure source vacuum unit and the target vacuum unit to be pre-pumped perform flow limiting and pressure equalization. S5. Determine the remaining pre-evacuation requirements based on the cavity pressure of the target vacuum unit to be pre-evacuated after flow limiting and pressure equalization and the process configuration, and generate vacuum pump replenishment control commands and connection path closure commands.

2. The method according to claim 1, characterized in that, The industrial vacuum mechanism model, based on the cavity pressures of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated, and the corresponding volumes in the volume configuration, forms the negative pressure capacity to be released, characterizing the capacity of the residual negative pressure source vacuum unit to replace the vacuum pump in receiving gas before venting. This includes: The cavity pressure of the residual negative pressure source vacuum unit is compared with the allowable exit pressure determined by the process configuration to obtain the releasable pressure difference; The cavity pressure of the target vacuum unit to be pre-evacuated is compared with the pre-evacuation target pressure determined by the process configuration to obtain the evacuation pressure difference; Using the industrial vacuum mechanism model, the releasable pressure difference and the pressure difference to be pumped are converted into the same gas dimension according to the vacuum unit volume in the volume configuration, the controllable connection path resistance obtained from the controllable connection path state, and the condensation load reduction term determined by the process configuration, and the smaller value is taken to form the negative pressure capacity to be released.

3. The method according to claim 1, characterized in that, The negative pressure capacity matching process includes: Based on the refining section, oil batch, cleaning level, preset material isolation rules, and valve position receipts in the controllable connection path status of the vacuum unit determined by the process configuration, vacuum unit pairs that do not meet the preset material isolation rules are eliminated. For the remaining vacuum units, the pre-evacuation requirement of the target vacuum unit to be pre-evacuated, determined by the process configuration, is converted into the pre-evacuation gas quantity, and the capacity utilization value is formed by the ratio of the negative pressure capacity to be released to the pre-evacuation gas quantity. Based on the path resistance obtained from the controllable connectivity path state, vacuum unit pairs that exceed the allowable resistance determined by the process configuration are eliminated, and the pair with the highest capacity utilization value among the remaining vacuum unit pairs is determined as the permissible pair. The controllable connectivity path corresponding to the license pair is determined as the target connectivity path, and the negative pressure transfer license is generated.

4. The method according to claim 1, characterized in that, For any controllable connectivity path, the determination of the preset process isolation condition includes: Read the valve position receipt of the controllable connection path from the controllable connection path status, and confirm that the isolation valve is in a controllable state when the valve position receipt indicates that the isolation valve is adjustable; Read the oil batch, cleaning level and preset material isolation rules of the vacuum units at both ends of the controllable connection path from the process configuration, and confirm the material isolation permission when the oil batch and cleaning level of the vacuum units at both ends meet the preset material isolation rules; Read the operation receipt of at least one of the condenser and trap in the controllable connection path from the controllable connection path status, and confirm the volatile interception permission when the operation receipt meets the preset volatile interception state determined by the process configuration. Obtain the oxygen content sampling value of the target vacuum unit to be pre-evacuated, compare the oxygen content sampling value with the process allowable oxygen content determined by the process configuration, and confirm the low oxygen maintenance condition when the oxygen content sampling value does not exceed the process allowable oxygen content; When the controllable state, material isolation permission, volatile substance interception permission, and low oxygen maintenance conditions are all met, it is determined that the state of the controllable connection path meets the preset process isolation conditions.

5. The method according to claim 1, characterized in that, The step of controlling the vacuum pump to reduce its suction output based on the negative pressure transfer permission, and controlling the target connection path to limit the flow and equalize the pressure between the residual negative pressure source vacuum unit and the target vacuum unit to be pre-pumped, includes: When generating the negative pressure transfer permission, a load reduction command is output to the vacuum pump, causing the vacuum pump's suction output to switch from maintaining suction output to compensating suction output. Read the valve position acknowledgment and path resistance of the target connection path from the controllable connection path status, and determine the valve opening change rate based on the valve position acknowledgment and path resistance; The opening of the connecting valve is adjusted according to the pressure difference between the cavity pressure of the residual negative pressure source vacuum unit and the cavity pressure of the target vacuum unit to be pre-evacuated, so that the gas enters the residual negative pressure source vacuum unit from the target vacuum unit to be pre-evacuated. The amount of gas transferred is calculated based on the pressure change in the cavity of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated, and the amount of gas transferred is subtracted from the negative pressure capacity to be released to obtain the current remaining value of the negative pressure capacity to be released. When any of the following termination conditions are met: the pressure difference between the two cavities is not greater than the equalization termination difference value determined by the process configuration, or the current remaining value of the negative pressure capacity to be released is not greater than the lower limit of the capacity determined by the process configuration, the target connection path is closed.

6. The method according to claim 1, characterized in that, The process involves determining the remaining pre-evacuation requirements based on the cavity pressure of the target vacuum unit after pressure equalization and the process configuration, and generating vacuum pump replenishment control commands and connection path closure commands, including: After limiting the flow and equalizing the pressure, the cavity pressure of the target vacuum unit to be pre-evacuated is read; The remaining pre-evacuation requirement is obtained by comparing the pressure in the cavity with the pre-evacuation target pressure determined by the process configuration. Obtain the operating status of the vacuum pump and determine the current available pumping capacity of the vacuum pump based on the operating status; The supplementary pumping output is determined based on the remaining pre-pumping requirement and the current available pumping capacity of the vacuum pump. Send a vacuum pump supplementary pumping control command containing the supplementary pumping output to the vacuum pump, and send a connection path closing command to the connection valve of the target connection path.

7. The method according to claim 1, characterized in that, When multiple residual negative pressure source vacuum units and multiple target vacuum units to be pre-evacuated exist, the capacity to be released negative pressure is pre-occupied and scheduled, including: Establish a capacity record for each residual negative pressure source vacuum unit, and write the source unit identifier, the initial value of the negative pressure to be released, and the current remaining capacity into the capacity record; The remaining time of stage switching obtained from the stage switching signal is converted into time urgency, and the amount of pre-extraction required gas obtained from the pre-extraction requirement determined by the process configuration is converted into demand occupancy. The time urgency and the demand occupancy are weighted according to the preset weight determined by the process configuration to form a target priority. According to the target priority, select the source unit identifier from the capacity record with the current remaining capacity, and determine the occupancy amount allocated to the target vacuum unit to be pre-pumped based on the current remaining capacity in the capacity record and the amount of gas required for pre-pumping. Write the source unit identifier, the target unit identifier of the target vacuum unit to be pre-pumped, and the occupancy amount into the pre-occupancy record, and deduct the occupancy amount from the current remaining capacity in the capacity record. When the corresponding negative pressure transfer is completed, confirm that the occupied amount is the consumed amount; If either the corresponding negative pressure transfer is cancelled or the corresponding negative pressure transfer is not started within the permitted period obtained by the phase switching signal, the current remaining capacity in the capacity record corresponding to the source unit identifier is replenished according to the source unit identifier and occupancy in the pre-occupancy record.

8. The method according to claim 1, characterized in that, The following abnormal handling procedures are also included in the negative pressure capacity matching and current limiting and pressure equalization processes: When the negative pressure transfer permission is not generated, it is prohibited to open the controllable connection path that has not obtained the negative pressure transfer permission, and the target vacuum unit to be pre-evacuated is switched to direct pre-evacuation by the vacuum pump; When the preset process isolation condition fails during the current limiting and pressure equalization process, the already opened target connection path is closed, and the target vacuum unit to be pre-evacuated is switched to direct pre-evacuation by the vacuum pump. When the residual negative pressure source vacuum unit still has a vacuum exit request obtained from the stage switching signal, there is no negative pressure transfer permission, the residual negative pressure source vacuum unit is within the allowable pressure holding period determined by the stage switching signal and the subsequent target vacuum unit to be pre-evacuated is identified by the stage switching signal, the residual negative pressure source vacuum unit is kept in isolation and pressure holding. When the residual negative pressure source vacuum unit still has a vacuum exit request obtained from the stage switching signal, there is no negative pressure transfer permission, and the exit venting condition is met, an inert gas controlled venting command is output to the residual negative pressure source vacuum unit. The exit venting condition includes at least one of the following: the residual negative pressure source vacuum unit is not in the allowable pressure holding period determined by the stage switching signal, and the stage switching signal has not identified any subsequent target vacuum unit to be pre-evacuated. Record the reasons for matching failures corresponding to the failure of the preset process isolation conditions, and update the availability status of the corresponding controllable connectivity path based on the recorded reasons.

9. An energy consumption optimization control system for a vacuum system used in vegetable oil refining, characterized in that, To implement the method of claim 1, the method comprises: The source target identification module is used to acquire the stage switching signal, cavity pressure, volume configuration, process configuration and controllable connection path status of each vacuum unit, and to determine the residual negative pressure source vacuum unit in the vacuum exit stage and the target vacuum unit to be pre-evacuated in the vacuum entry stage based on the stage switching signal. The negative pressure capacity forming module is used to form a negative pressure capacity to be released, which characterizes the residual negative pressure source vacuum unit as a substitute for the vacuum pump to receive gas before release, based on the industrial vacuum mechanism model, according to the cavity pressure of the residual negative pressure source vacuum unit and the target vacuum unit to be pre-evacuated, and the corresponding volume in the volume configuration. The matching permission module is used to perform negative pressure capacity matching processing on the negative pressure capacity to be released and the pre-evacuation requirement of the target vacuum unit to be pre-evacuated as determined by the process configuration when the preset process isolation conditions are met based on the state of the controllable connection path and the process configuration, thereby determining the negative pressure transfer permission and the target connection path; The current limiting and pressure equalization control module is used to control the vacuum pump to reduce the suction output according to the negative pressure transfer permission, and to control the target connection path to make the residual negative pressure source vacuum unit and the target vacuum unit to be pre-pumped perform current limiting and pressure equalization. The supplementary pumping instruction generation module is used to determine the remaining pre-pumping requirements based on the cavity pressure of the target vacuum unit to be pre-pumped after flow limiting and pressure equalization and the process configuration, and to generate vacuum pump supplementary pumping control instructions and connection path closure instructions.

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