An etad model creping dryer steam heat energy recovery system and control method

Abstract

The present application relates to the technical field of industrial waste heat recovery, in particular to an ETAD model creping dryer steam heat energy recovery system. In view of the problem of low flash steam recovery rate, large steam pressure fluctuation and unstable paper quality in the prior art, the present application sets a multi-stage flash recovery subsystem composed of several flash tanks, and cooperates with two-stage injection heat pumps to mix the flash steam with the main steam and then recycle it to the dryer. The system integrates an intelligent control subsystem to collect pressure, liquid level and base paper quality data in real time, dynamically adjust the heat pump valve opening and condensate water discharge, and ensure the stability of the steam pressure. The technical scheme effectively improves the steam heat energy utilization rate and reduces the energy consumption, and at the same time, through precise heat compensation control, the uniformity of the base paper basis weight and moisture is ensured, which has significant energy saving and quality improving effect.

Description

Technical Field

[0001] This invention belongs to the field of industrial waste heat recovery technology, and in particular relates to a steam heat energy recovery system and control method for the wrinkling drying cylinder of the ETAD model. Background Technology

[0002] In the tissue paper industry, the application of heat recovery technology exhibits a significant imbalance. Current research and development primarily focus on large drying cylinder systems, while less attention is paid to flash steam recovery in small drying cylinders, resulting in relatively scarce application of this technology. In actual production, most companies still directly discharge the flash steam generated in small drying cylinders, leading to an overall energy utilization rate far below the industry average and significant energy waste. Existing steam recovery equipment is mostly of a general design, lacking customized solutions for the "multi-unit collaborative control" characteristics of ETAD models. This often causes problems such as pressure fluctuations and uneven temperature distribution within the cylinder during actual operation, making it difficult to meet the demands of high-precision production.

[0003] In terms of intelligent control, the level of automation in the industry still needs improvement. Only a few leading companies have achieved monitoring of basic parameters such as flash tank liquid level and steam flow rate, and a closed-loop control system covering differential pressure, flow rate, and product quality has not yet been established. This extensive management model is difficult to match the stringent requirements of ETAD models for the stability of process parameters, limiting further improvements in production efficiency and product quality. Summary of the Invention

[0004] To address the significant energy waste caused by the direct discharge of flash steam in the creping drying cylinder system of the ETAD machine, and the unstable paper quality due to large fluctuations in steam pressure, this invention provides a flash steam recovery heat compensation system and control method for the creping drying cylinder of the TAD machine. Through multi-stage flash steam recovery and intelligent feedback control, the system achieves efficient recovery and stable reuse of flash steam, effectively reducing energy consumption while ensuring the process stability of paper quality.

[0005] To achieve the above objectives, a steam heat recovery system for the wrinkling drying cylinder of an ETAD machine is provided in a first aspect of the present invention, comprising: The multi-stage flash recovery subsystem includes several flash tanks connected in series, used to receive high-temperature condensate from the drying cylinder and generate flash steam; The steam heat compensation subsystem includes a two-stage ejector heat pump, which has a main steam inlet, an ejector steam inlet, and a mixed steam outlet. The mixed steam outlet is connected to the steam inlet of the wrinkling drying cylinder. The intelligent control subsystem includes a central controller, pressure and level sensors installed on the flash tank, flow meters installed on the steam pipes of the drying cylinder, and an online paper quality detector installed at the paper machine outlet. The central controller is electrically connected to the pressure sensor, liquid level sensor, flow meter, online paper quality detector 35, and heat pump regulating valve, respectively, and is used to receive detection signals and output control commands.

[0006] Furthermore, the multi-stage flash evaporation recovery subsystem also includes a recovery pipeline assembly, which includes a first conveying pipeline and a second conveying pipeline that are sequentially connected to each stage of the flash tank; The first and second delivery pipelines are connected in series with a shut-off valve, a check valve, and a filter along the fluid flow direction. The check valve is used to restrict the reverse flow of condensate between adjacent flash tanks, and the filter is used to remove solid impurities from the condensate; the outer wall of the recovery pipeline assembly is covered with an insulation layer, and the bottom of the recovery pipeline assembly is connected to a drain branch.

[0007] Furthermore, the two-stage ejector heat pump includes a high-pressure stage ejector and a low-pressure stage ejector. The nozzle of the high-pressure stage ejector is connected to the main steam source, and the inlet of the low-pressure stage ejector is connected to the exhaust steam outlet of the flash tank. The two-stage ejector heat pump is equipped with a backup ejector branch, which is equipped with an electromagnetic switch valve. When the exhaust steam pressure is detected to be lower than a preset lower limit, the central controller controls the opening of the backup ejector branch to maintain the pressure stability of the mixed steam.

[0008] Furthermore, the steam heat compensation subsystem also includes a bypass control pipeline and a venting control pipeline. The bypass control pipeline is equipped with a cylinder warming regulating valve, and the venting control pipeline is equipped with an automatic venting valve. The central controller is equipped with a stage control module, which is used to control the warm cylinder regulating valve to be in a fully open state during the equipment start-up and preheating stage, and to control the automatic vent valve to be in a closed state during the normal operation stage, and to open the automatic vent valve only when the system is overpressured.

[0009] Furthermore, the intelligent control subsystem also includes a human-machine interaction terminal and a data acquisition module. The data acquisition module includes a float-type level transmitter installed on the side wall of the flash tank and a vortex flow meter installed on the main steam pipeline. The human-machine interface terminal is connected to the central controller and is used to display real-time operating parameters, store historical data, and receive setting instructions from operators.

[0010] Furthermore, the online quality inspection instrument for raw paper includes a basis weight scanning frame, an infrared moisture sensor, and a thickness measuring roller. The online quality inspection instrument for raw paper is used to transmit the detected basis weight deviation, moisture content fluctuation, and surface flatness data of the raw paper to the central controller via wireless transmission. The central controller has a pre-stored quality standard database, which is used to compare and analyze real-time detection data with standard data.

[0011] Furthermore, it also includes an MES data docking unit, which includes an industrial gateway and a protocol converter. The industrial gateway is connected to the communication port of the central controller and is used to upload steam consumption, equipment operating status and raw paper quality statistics to the factory manufacturing execution system. It also includes an audible and visual alarm, which is used to receive a signal from the central controller to trigger an alarm when the liquid level in the flash tank exceeds the safety threshold or the heat pump outlet temperature is abnormal.

[0012] Furthermore, the central controller is equipped with a differential pressure regulation module and a flow statistics module. The differential pressure regulation module is connected to a differential pressure transmitter and is used to adjust the opening of the steam inlet valve according to the pressure difference between the steam inlet and the steam outlet of the drying cylinder. The flow statistics module is connected to an electromagnetic flow meter and is used to accumulate the total flow of recycled steam in real time and generate shift reports.

[0013] Secondly, the present invention also provides a steam heat energy recovery control method for the ETAD model wrinkling drying cylinder, applied to the steam heat energy recovery system of the ETAD model wrinkling drying cylinder as described in any one of the claims, comprising the following steps: The intelligent control subsystem collects pressure and liquid level data in the multi-stage flash evaporation and recovery subsystem in real time, as well as raw paper quality data fed back by the online raw paper quality detector. Based on the collected pressure data, the valve opening of the two-stage ejector heat pump is adjusted by the central controller to maintain the heat pump outlet steam pressure within the set range. Based on the collected liquid level data, the condensate drain valve is adjusted by the central controller to maintain the liquid level in the flash tank at the set height; Based on the data fed back by the online quality tester for raw paper, a quality feedback model is established through the central controller to dynamically adjust the heating temperature and steam flow of the drying cylinder.

[0014] Furthermore, the step of establishing a quality feedback model based on data from the online paper quality detector and dynamically adjusting the heating temperature and steam flow rate of the drying cylinder through a central controller specifically includes: When the basis weight test data of the raw paper exceeds the preset threshold, a temperature fine-tuning command is generated to control the heat pump or regulating valve to change the heating temperature of the drying cylinder. When the bulkiness test data of the base paper exceeds the preset threshold, a pressure adjustment command is generated to control the ejection pressure of the two-stage ejector heat pump. When the moisture content of the raw paper exceeds the preset threshold, a flow linkage command is generated to synchronously adjust the steam flow ratio between the large and small drying cylinders. The liquid level in the flash tank is monitored in real time. When the liquid level exceeds the preset range, the opening of the condensate drain valve is adjusted to maintain the liquid level feedback delay time within the preset range.

[0015] Thirdly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the tail steam recycling control method as described in any one of the claims.

[0016] The beneficial technical effects of the present invention are at least as follows: This invention provides a steam heat energy recovery system and control method for the wrinkling drying cylinder of the ETAD machine, the advantages of which are: Firstly, it achieves efficient cascaded recovery and utilization of flash steam. Through innovative flash tank pipeline linkage technology, it breaks through the efficiency bottleneck of the traditional single-tank recovery mode, constructs a continuous and stable flash recovery process, significantly improves the recovery rate of exhaust steam, significantly reduces heat energy waste in the production process, and greatly improves the overall energy utilization efficiency.

[0017] Secondly, it significantly improves the conversion efficiency and adaptability of the thermal energy system. Adopting a self-developed two-stage ejector heat pump structure, it not only improves the system's thermal efficiency compared to the industry average, but also possesses excellent load-following characteristics. This allows it to perfectly adapt to the complex operating conditions of the ETAD model under different production loads, effectively solving the technical defects of traditional general-purpose heat pump equipment, such as poor load matching and rapid energy efficiency degradation under specific operating conditions.

[0018] Thirdly, a closed-loop intelligent control system for the entire process has been constructed. By establishing a deep closed-loop control logic of "differential pressure regulation - flow statistics - quality linkage," a technological leap from basic data monitoring to precise process control has been achieved. This system can sense and respond quickly to dynamic fluctuations in steam parameters in real time, automatically adjust the system's operating status, and ensure the long-term stability of heating parameters. This effectively avoids defects in the quality of raw paper caused by parameter fluctuations, ensuring the continuity and high quality of production.

[0019] Fourth, a customized quality control model based on raw material characteristics was developed. Specifically, a multi-parameter correlation model of "temperature-pressure-quality" was developed to address the characteristics of wood pulp blends commonly used in the papermaking industry. By accurately fitting the intrinsic relationship between raw material characteristics and process parameters, more refined control that better meets actual production needs was achieved. This avoids the control lag or over-adjustment problems that may occur with general control models under specific raw material conditions, further improving the stability of base paper quality and yield. Attached Figure Description

[0020] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the steam heat recovery system of the wrinkling drying cylinder of the ETAD model, one embodiment of the present invention; Figure 2 This invention discloses a flowchart illustrating the working steps of a steam heat energy recovery control method for the wrinkling drying cylinder of an ETAD machine, as shown in one embodiment of the present invention. Figure 3 This is a diagram illustrating the working steps of dynamically adjusting the heating temperature and steam flow rate of the drying cylinder according to one embodiment of the present invention.

[0022] Figure descriptions: Multi-stage flash recovery subsystem 1; Steam heat compensation subsystem 2; Intelligent control subsystem 3; First flash tank 11; Second flash tank 12; Third flash tank 13; Central controller 31; Pressure sensor 32; Liquid level sensor 33; Flow meter 34; Online paper quality detector 35; Creping drying cylinder 4. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0024] Example 1 refer to Figure 1 This invention provides an embodiment of a steam heat recovery system for the wrinkling drying cylinder of an ETAD machine, comprising: The multi-stage flash recovery subsystem 1 includes several flash tanks connected in series, used to receive high-temperature condensate from the drying cylinder and generate flash steam; The steam heat compensation subsystem 2 includes a two-stage ejector heat pump, which has a main steam inlet, an ejector steam inlet, and a mixed steam outlet. The mixed steam outlet is connected to the steam inlet of the wrinkling drying cylinder. The intelligent control subsystem 3 includes a central controller 31, a pressure sensor 32 and a liquid level sensor 33 installed on the flash tank, a flow meter 34 installed on the steam pipe of the drying cylinder, and an online paper quality detector 35 installed at the paper machine outlet. The central controller 31 is electrically connected to the pressure sensor 32, the liquid level sensor 33, the flow meter 34, the online paper quality detector 35, and the regulating valve of the heat pump, respectively, and is used to receive detection signals and output control commands.

[0025] In this embodiment, a flash steam recovery heat compensation system for the creping drying cylinder of the ETAD machine is provided, which aims to solve the problems of low steam utilization and unstable paper quality in the prior art.

[0026] The steam heat recovery system of the ETAD model's wrinkling drying cylinder includes a multi-stage flash evaporation recovery subsystem, a steam heat compensation subsystem, and an intelligent control subsystem.

[0027] The multi-stage flash recovery subsystem 1 includes three flash tanks connected in series. The high-temperature condensate from the drying cylinder first enters the first flash tank 11, and the generated secondary steam and unflashed liquid sequentially enter the second flash tank 12 and the third flash tank 13, realizing "three-tank linkage recovery" and recycling the flash steam that was originally directly discharged.

[0028] The core of the steam heat compensation subsystem is a two-stage ejector heat pump. This heat pump mixes the recovered low-pressure flash steam (exhaust steam) with high-pressure main steam (pressure approximately 2.0-2.3 MPa), and increases the pressure and temperature through ejection. The mixed steam (temperature 130-135℃) is then returned to the wrinkling drying cylinder 5 for reuse.

[0029] The intelligent control subsystem 3 includes a central controller 31 (PLC), a pressure sensor 32, a liquid level sensor 33, a flow meter 34, and an online paper quality detector 35. The central controller receives signals from each sensor and outputs control commands based on real-time operating conditions to achieve closed-loop control of the entire system.

[0030] Furthermore, the multi-stage flash evaporation recovery subsystem 1 also includes a recovery pipeline assembly, which includes a first conveying pipeline and a second conveying pipeline that are sequentially connected to each stage of the flash tanks; The first and second delivery pipelines are connected in series with a shut-off valve, a check valve, and a filter along the fluid flow direction. The check valve is used to restrict the reverse flow of condensate between adjacent flash tanks, and the filter is used to remove solid impurities from the condensate; the outer wall of the recovery pipeline assembly is covered with an insulation layer, and the bottom of the recovery pipeline assembly is connected to a drain branch.

[0031] In this embodiment, the multi-stage flash evaporation recovery subsystem includes a recovery piping assembly, which comprises a first delivery piping (for condensate delivery) and a second delivery piping (for flash steam delivery) connecting each stage of the flash tank. The following lines are connected in series along the fluid flow direction on the piping: Gate valves are used for pipeline maintenance and shut-off.

[0032] The check valve is installed on the condensate line to strictly limit the backflow of condensate between adjacent flash tanks and prevent the flash efficiency from decreasing due to backflow caused by pressure difference.

[0033] The filter is installed in the steam and condensate lines to remove solid impurities (such as pipe rust) from the condensate and prevent impurities from clogging the heat pump nozzles.

[0034] In addition, the outer wall of the recovery pipeline assembly is covered with a 50mm thick insulation layer (thermal conductivity ≤0.03W / (m·K)) to reduce heat loss during transportation; the bottom of the pipeline is connected to a drain branch for periodically discharging deposited dirt. Furthermore, the two-stage ejector heat pump includes a high-pressure stage ejector and a low-pressure stage ejector. The nozzle of the high-pressure stage ejector is connected to the main steam source, and the inlet of the low-pressure stage ejector is connected to the exhaust steam outlet of the flash tank. The two-stage ejector heat pump is equipped with a backup ejector branch, which is equipped with an electromagnetic switch valve. When the exhaust steam pressure is detected to be lower than a preset lower limit, the central controller controls the opening of the backup ejector branch to maintain the pressure stability of the mixed steam.

[0035] In this embodiment, the two-stage ejector heat pump consists of a high-pressure stage ejector and a low-pressure stage ejector connected in series.

[0036] Referring to Table 1, based on different load conditions of the ETAD model, a customized "two-stage ejector" structure heat pump is designed, with the following core parameters: Table 1 The high-pressure ejector has its nozzle connected to the main steam source (pressure 2.0-2.3MPa) as a power source.

[0037] The low-pressure stage ejector has its inlet connected to the exhaust steam outlet of flash tank #3 (pressure 0.11-0.17 MPa). The heat pump is equipped with a backup ejector branch. This branch is equipped with an electromagnetic switch valve. When the central controller detects that the exhaust steam pressure is lower than the preset lower limit (e.g., 0.11 MPa), it automatically opens the backup ejector branch, introducing auxiliary steam to maintain the pressure stability of the mixed steam, ensuring that the drying cylinder temperature still meets the process requirements under low load conditions (ejector coefficient reaches 0.86).

[0038] Furthermore, the steam heat compensation subsystem also includes a bypass control pipeline and a venting control pipeline. The bypass control pipeline is equipped with a cylinder warming regulating valve, and the venting control pipeline is equipped with an automatic venting valve. The central controller is equipped with a stage control module, which is used to control the warm cylinder regulating valve to be in a fully open state during the equipment start-up and preheating stage, and to control the automatic vent valve to be in a closed state during the normal operation stage, and to open the automatic vent valve only when the system is overpressured.

[0039] In this embodiment, the steam heat compensation subsystem further includes a bypass control pipeline and a venting control pipeline.

[0040] Bypass control pipeline: Equipped with a cylinder warming regulating valve. The central controller is equipped with a stage control module. During the equipment start-up preheating stage (first 30 minutes), the cylinder warming regulating valve is controlled to be at a large opening (80%) to quickly increase the cylinder temperature using the bypass. During normal operation, it is closed to 10%-15% for energy-saving operation.

[0041] The venting control pipeline is equipped with an automatic venting valve. The central controller controls this valve to open only when the system is overpressured (e.g., flash tank pressure > 0.2 MPa), and keeps it closed during normal operation to ensure that the amount of vented steam is reduced by more than 90%, achieving zero or extremely low emissions.

[0042] Furthermore, the intelligent control subsystem also includes a human-machine interaction terminal and a data acquisition module. The data acquisition module includes a float-type level transmitter installed on the side wall of the flash tank and a vortex flow meter installed on the main steam pipeline. The human-machine interface terminal is connected to the central controller and is used to display real-time operating parameters, store historical data, and receive setting instructions from operators.

[0043] In this embodiment, the hardware components of the intelligent control subsystem include a human-machine interface (HMI) and a data acquisition module.

[0044] The data acquisition module includes a float-type level transmitter (high accuracy, high temperature resistance) installed on the side wall of the flash tank for real-time monitoring of the liquid level; and a vortex flow meter (range 0-500kg / h, accuracy ±1%) installed on the main steam pipeline for measuring steam flow.

[0045] Human-Machine Interface Terminal: Connected to the central controller via Ethernet. Operators can view real-time operating parameters (such as pressure and temperature curves), store historical data, and input new setting commands (such as target liquid level 1 / 2-2 / 3) through the HMI, achieving unmanned operation.

[0046] Furthermore, the online quality inspection instrument for raw paper includes a basis weight scanning frame, an infrared moisture sensor, and a thickness measuring roller. The online quality inspection instrument for raw paper is used to transmit the detected basis weight deviation, moisture content fluctuation, and surface flatness data of the raw paper to the central controller via wireless transmission. The central controller has a pre-stored quality standard database, which is used to compare and analyze real-time detection data with standard data.

[0047] In this embodiment, the online paper quality detector is installed at the paper machine exit (at a speed of 1200 m / min) and includes: A basis weight scanning frame is used to detect basis weight deviation in the base paper. An infrared moisture sensor is used to detect moisture content fluctuations. A thickness measuring roller is used to detect surface flatness and wrinkles. The detection data is transmitted to the central controller wirelessly (such as industrial WiFi or 5G). The controller has a pre-stored quality standard database (such as basis weight deviation ±2g / m², moisture fluctuation ±1%), compares the real-time data with the standards, and triggers a compensation mechanism if the standard is exceeded.

[0048] Furthermore, it also includes an MES data docking unit, which includes an industrial gateway and a protocol converter. The industrial gateway is connected to the communication port of the central controller and is used to upload steam consumption, equipment operating status and raw paper quality statistics to the factory manufacturing execution system. It also includes an audible and visual alarm, which is used to receive a signal from the central controller to trigger an alarm when the liquid level in the flash tank exceeds the safety threshold or the heat pump outlet temperature is abnormal.

[0049] This embodiment also includes an MES data interface unit, comprising an industrial gateway and a protocol converter (supporting Modbus TCP to Profinet). The industrial gateway connects to the central controller, uploading steam consumption, equipment operating status, and raw paper quality statistics to the factory's Manufacturing Execution System (MES) for visualized energy data management. An audible and visual alarm is also included. When the flash tank liquid level exceeds the safety threshold (too high or too low) or the heat pump outlet temperature is abnormal (exceeding the 130-135°C range), the central controller activates the audible and visual alarm to sound and flash, alerting on-site personnel to handle the situation and prevent equipment damage.

[0050] Furthermore, the central controller is equipped with a differential pressure regulation module and a flow statistics module. The differential pressure regulation module is connected to a differential pressure transmitter and is used to adjust the opening of the steam inlet valve according to the pressure difference between the steam inlet and the steam outlet of the drying cylinder. The flow statistics module is connected to an electromagnetic flow meter and is used to accumulate the total flow of recycled steam in real time and generate shift reports.

[0051] In this embodiment, the central controller also includes a differential pressure regulation module and a flow statistics module.

[0052] The differential pressure regulating module is connected to a differential pressure transmitter to collect the pressure difference between the steam inlet and outlet of the drying cylinder in real time. The controller dynamically adjusts the opening of the steam inlet valve according to this difference (target 0.08-0.1MPa) to ensure smooth steam flow and prevent uneven cylinder surface temperature caused by excessive pressure difference.

[0053] The flow statistics module connects to an electromagnetic flow meter, which accumulates the total flow rate of recycled steam (i.e., the amount of flash steam recovered) in real time and generates reports by shift. This data is used to calculate energy-saving benefits (an annual reduction in steam consumption of approximately 2,560 tons).

[0054] Secondly, the present invention also provides a steam heat energy recovery control method for the ETAD model wrinkling drying cylinder, applied to the steam heat energy recovery system of the ETAD model wrinkling drying cylinder as described in any one of the claims, comprising the following steps: S1. The intelligent control subsystem collects pressure and liquid level data in the multi-stage flash evaporation recovery subsystem in real time, as well as raw paper quality data fed back by the online raw paper quality detector. S2. Based on the collected pressure data, the valve opening of the two-stage ejector heat pump is adjusted by the central controller to maintain the heat pump outlet steam pressure within the set range. S3. Based on the collected liquid level data, the condensate drain valve is adjusted through the central controller to maintain the liquid level in the flash tank at the set height. S4. Based on the data fed back by the online quality tester of raw paper, a quality feedback model is established through the central controller to dynamically adjust the heating temperature and steam flow of the drying cylinder.

[0055] In this embodiment, the intelligent control subsystem is activated to collect pressure and liquid level data from the multi-stage flash evaporation and recovery subsystem in real time, as well as basis weight, moisture content, and flatness data fed back by the online paper quality analyzer. Subsequently, based on the collected pressure data, the central controller adjusts the valve openings of the two-stage ejector heat pumps using a PID algorithm to ensure that the pressure of the mixed steam after ejection remains stable within the set range (0.10-0.35 MPa), meeting the heating requirements of the small drying cylinder. Simultaneously, based on the liquid level data, the condensate discharge valve is adjusted to maintain the liquid level in the flash tank at a set height (1 / 2-2 / 3). Finally, based on the data fed back by the online paper quality analyzer, the system establishes a quality feedback model. When excessive moisture or basis weight deviation is detected, the model automatically calculates and dynamically adjusts the heating temperature and steam flow rate of the drying cylinder, achieving fully automated control of the entire process.

[0056] Furthermore, the step of establishing a quality feedback model based on data from the online paper quality detector and dynamically adjusting the heating temperature and steam flow rate of the drying cylinder through a central controller specifically includes: S41. When the basis weight detection data of the raw paper exceeds the preset threshold, a temperature fine-tuning command is generated to control the heat pump or regulating valve to change the heating temperature of the drying cylinder. S42. When the bulkiness detection data of the base paper exceeds the preset threshold, a pressure adjustment command is generated to control the ejection pressure of the two-stage ejector heat pump. S43. When the moisture content detection data of the raw paper exceeds the preset threshold, a flow linkage command is generated to synchronously adjust the steam flow ratio between the large drying cylinder and the small drying cylinder. S44. Monitor the liquid level of the flash tank in real time. When the liquid level exceeds the preset range, adjust the opening of the condensate drain valve to maintain the liquid level feedback delay time within the preset range.

[0057] In this embodiment, when the basis weight detection data of the raw paper exceeds a preset threshold (e.g., > ±2 g / m²), the system generates a temperature fine-tuning command, controlling the heat pump or regulating valve to fine-tune the heating temperature of the drying cylinder by ±1°C to change the drying rate. When the basis weight bulk detection data exceeds a preset threshold (e.g., fluctuation > ±4%), the system generates a pressure adjustment command, controlling the ejector pressure of the two-stage ejector heat pump to adjust by ±0.02 MPa, changing the internal pressure environment of the drying cylinder. When the basis weight moisture content detection data exceeds a preset threshold (e.g., fluctuation > ±1%), the system generates a flow linkage command, synchronously adjusting the steam flow ratio between the large and small drying cylinders (e.g., small drying cylinder ±50 kg / h) to achieve full-section drying balance. Furthermore, the system monitors the flash tank liquid level in real time. When the liquid level exceeds a preset range, it adjusts the opening of the condensate drain valve. Through optimized control algorithms, the system controls the liquid level feedback delay time to within 2 seconds, ensuring rapid response and stable operation of the entire thermal compensation system.

[0058] Thirdly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the tail steam recycling control method as described in any one of the claims.

[0059] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods in the various embodiments of this application. The aforementioned storage medium includes: USB flash drive, mobile hard drive, read-only memory (ROM). ROM (ROM), RAM (Random Access Memory), magnetic disks, optical disks, and other media that can store programs.

Claims

1. A steam heat recovery system for the pleating drying cylinder of an ETAD machine, characterized in that, include: The multi-stage flash recovery subsystem includes several flash tanks connected in series, used to receive high-temperature condensate from the drying cylinder and generate flash steam; The steam heat compensation subsystem includes a two-stage ejector heat pump, which has a main steam inlet, an ejector steam inlet, and a mixed steam outlet. The mixed steam outlet is connected to the steam inlet of the wrinkling drying cylinder. The intelligent control subsystem includes a central controller, pressure and level sensors installed on the flash tank, flow meters installed on the steam pipes of the drying cylinder, and an online paper quality detector installed at the paper machine outlet. The central controller is electrically connected to the pressure sensor, liquid level sensor, flow meter, online paper quality detector, and heat pump regulating valve, respectively, and is used to receive detection signals and output control commands.

2. The steam heat recovery system for the ETAD model wrinkling drying cylinder according to claim 1, characterized in that, The multi-stage flash evaporation recovery subsystem also includes a recovery pipeline assembly, which includes a first delivery pipeline and a second delivery pipeline that are sequentially connected to each of the flash tanks at each stage. The first and second delivery pipelines are connected in series with a shut-off valve, a check valve, and a filter along the fluid flow direction. The check valve is used to restrict the reverse flow of condensate between adjacent flash tanks, and the filter is used to remove solid impurities from the condensate; the outer wall of the recovery pipeline assembly is covered with an insulation layer, and the bottom of the recovery pipeline assembly is connected to a drain branch.

3. The steam heat recovery system for the ETAD model wrinkling drying cylinder according to claim 1, characterized in that, The two-stage ejector heat pump includes a high-pressure stage ejector and a low-pressure stage ejector. The nozzle of the high-pressure stage ejector is connected to the main steam source, and the inlet of the low-pressure stage ejector is connected to the exhaust steam outlet of the flash tank. The two-stage ejector heat pump is equipped with a backup ejector branch, which is equipped with an electromagnetic switch valve. When the exhaust steam pressure is detected to be lower than a preset lower limit, the central controller controls the opening of the backup ejector branch to maintain the pressure stability of the mixed steam.

4. The steam heat recovery system for the ETAD model wrinkling drying cylinder according to claim 1, characterized in that, The steam heat compensation subsystem also includes a bypass control pipeline and a venting control pipeline. The bypass control pipeline is equipped with a cylinder warming regulating valve, and the venting control pipeline is equipped with an automatic venting valve. The central controller is equipped with a stage control module, which is used to control the warm cylinder regulating valve to be in a fully open state during the equipment start-up and preheating stage, and to control the automatic vent valve to be in a closed state during the normal operation stage, and to open the automatic vent valve only when the system is overpressured.

5. The steam heat recovery system for the ETAD model wrinkling drying cylinder according to claim 1, characterized in that, The intelligent control subsystem also includes a human-machine interaction terminal and a data acquisition module. The data acquisition module includes a float-type level transmitter installed on the side wall of the flash tank and a vortex flow meter installed on the main steam pipeline. The human-machine interface terminal is connected to the central controller and is used to display real-time operating parameters, store historical data, and receive setting instructions from operators.

6. The steam heat recovery system for the ETAD model wrinkling drying cylinder according to claim 1, characterized in that, The online quality detector for raw paper includes a basis scanning frame, an infrared moisture sensor, and a thickness measuring roller. The online quality detector for raw paper is used to transmit the detected basis deviation, moisture content fluctuation, and surface flatness data of the raw paper to the central controller via wireless transmission. The central controller has a pre-stored quality standard database, which is used to compare and analyze real-time detection data with standard data.

7. The steam heat recovery system for the ETAD model wrinkling drying cylinder according to claim 1, characterized in that, It also includes an MES data interface unit, which includes an industrial gateway and a protocol converter. The industrial gateway is connected to the communication port of the central controller and is used to upload steam consumption, equipment operating status and raw paper quality statistics to the factory manufacturing execution system. It also includes an audible and visual alarm, which is used to receive a signal from the central controller to trigger an alarm when the liquid level in the flash tank exceeds the safety threshold or the heat pump outlet temperature is abnormal.

8. The steam heat recovery system for the ETAD model wrinkling drying cylinder according to claim 1, characterized in that, The central controller is equipped with a differential pressure regulation module and a flow statistics module. The differential pressure regulation module is connected to a differential pressure transmitter and is used to adjust the opening of the steam inlet valve according to the pressure difference between the steam inlet and the steam outlet of the drying cylinder. The flow statistics module is connected to an electromagnetic flow meter and is used to accumulate the total flow of recycled steam in real time and generate shift reports.

9. A method for controlling the steam heat energy recovery of the wrinkling drying cylinder in an ETAD machine, characterized in that, The steam heat recovery system for the wrinkling drying cylinder of the ETAD machine as described in any one of claims 1-8 includes the following steps: The intelligent control subsystem collects pressure and liquid level data in the multi-stage flash evaporation and recovery subsystem in real time, as well as raw paper quality data fed back by the online raw paper quality detector. Based on the collected pressure data, the valve opening of the two-stage ejector heat pump is adjusted by the central controller to maintain the heat pump outlet steam pressure within the set range. Based on the collected liquid level data, the condensate drain valve is adjusted by the central controller to maintain the liquid level in the flash tank at the set height; Based on the data fed back by the online quality tester for raw paper, a quality feedback model is established through the central controller to dynamically adjust the heating temperature and steam flow of the drying cylinder.

10. The steam heat energy recovery control method for the ETAD model wrinkling drying cylinder according to claim 9, characterized in that, The step of establishing a quality feedback model through a central controller based on data from the online paper quality detector, and dynamically adjusting the heating temperature and steam flow of the drying cylinder, specifically includes: When the basis weight test data of the raw paper exceeds the preset threshold, a temperature fine-tuning command is generated to control the heat pump or regulating valve to change the heating temperature of the drying cylinder. When the bulkiness test data of the base paper exceeds the preset threshold, a pressure adjustment command is generated to control the ejection pressure of the two-stage ejector heat pump. When the moisture content of the raw paper exceeds the preset threshold, a flow linkage command is generated to synchronously adjust the steam flow ratio between the large and small drying cylinders. The liquid level in the flash tank is monitored in real time. When the liquid level exceeds the preset range, the opening of the condensate drain valve is adjusted to maintain the liquid level feedback delay time within the preset range.

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