A method of improving a combination of pressure swing adsorption valve settings

Abstract

The present application relates to the technical field of gas separation, and particularly relates to a combined improvement method for pressure swing adsorption valve setting, comprising the following steps: integrating a plurality of pressure swing adsorption valves in a pressure swing adsorption system into a valve block; obtaining a change trend of sound intensity in a frequency band by acquiring acoustic characteristics of the valve block; adjusting an adsorption pressure threshold; determining a valve acoustic characteristic sampling point according to an equal pressure triggering condition, obtaining valve acoustic characteristic adjustment valve closing strategy; determining a final opening degree of an equal pressure valve according to an acoustic turbulent flow index, a pressure difference opening degree and a valve block temperature rise rate, determining whether to open a fixed switch of the equal pressure valve; determining a reason for the increase of sound intensity in the frequency band according to a change of pressure of the valve block and an acoustic pulse cluster meeting a judgment condition; determining a risk of insufficient regeneration according to a valve block temperature fluctuation, adjusting a flushing stage timing and an initial adsorption duration in the equal pressure triggering condition. The present application simplifies system structure and improves control accuracy by integrating a plurality of valves into a valve block.

Description

Technical Field

[0001] The present invention relates to the technical field of gas separation, and in particular to a combined improvement method for pressure swing adsorption valve settings. Background Art

[0002] Pressure Swing Adsorption (PSA) is a highly efficient and environmentally friendly gas separation technology widely used for the separation and purification of gases such as hydrogen, oxygen, and nitrogen. PSA achieves precise separation of mixed gases through cyclic adsorption and desorption of adsorbents, combined with valve mechanisms. In a PSA system, valves are key components responsible for gas switching, distribution, and pressure control. Therefore, valve selection and design directly determine system operating efficiency and gas purity, directly impacting separation efficiency and product purity.

[0003] Chinese Patent Publication No.: CN118391484A discloses an intelligent control valve for a pressure swing adsorption nitrogen production device and its control method. The intelligent control valve includes an input module for receiving a purity electrical signal corresponding to the oxygen purity measured by an oxygen analyzer per unit time; a logic module for converting the received purity electrical signal into a corresponding control electrical signal; a control module for generating a valve control electrical signal based on the received control electrical signal; a valve execution module for adjusting the degree of valve opening; and a proportional control module for controlling the operation of the valve execution module based on the valve control electrical signal. It can be seen that the intelligent control valve for a pressure swing adsorption nitrogen production device and its control method have the following problems:

[0004] In traditional pressure swing adsorption systems, the dispersed arrangement of valves requires a large number of connecting pipes, resulting in lengthy flow paths and numerous elbows. This increases gas flow resistance and reduces system efficiency. The number of flange or threaded connection points between pipes and valves increases, and potential leakage points increase. This is especially evident in high-frequency switching PSA systems. Valves are dispersed in multiple locations, and a large number of pipes and joints need to be checked during maintenance, which is time-consuming and labor-intensive. This results in complex pressure swing adsorption system piping, large pressure drop, and high energy consumption. Summary of the Invention

[0005] To this end, the present invention provides a combined improvement method for pressure swing adsorption valve settings to overcome the problems in the prior art of dispersed arrangement of valves leading to complex piping, large pressure drop, and high energy consumption in the pressure swing adsorption system.

[0006] To achieve the above objectives, the present invention provides a combined improvement method for pressure swing adsorption valve settings, comprising:

[0007] Integrating a plurality of the pressure swing adsorption valves in the pressure swing adsorption system into a valve block, and connecting the valve block to other equipment in the pressure swing adsorption system;

[0008] acquire a valve block acoustic feature of the valve block according to an initial detection cycle, determine a frequency band sound intensity trend according to the valve block acoustic feature, and trigger an adsorption tower switching to open an equalizing valve in the valve block according to a change trend or according to an equalizing trigger condition;

[0009] determine a valve acoustic feature sampling point according to the equalizing trigger condition, acquire valve acoustic features of several valves in the valve block at the determined valve acoustic feature sampling point, and adjust a valve closing strategy in the valve block according to the valve acoustic features;

[0010] When the equalizing valve in the valve block is triggered to open, the final opening degree of the equalizing valve is determined according to an acoustic turbulent flow index, a differential pressure opening degree of the adsorption tower, and a valve block temperature rise rate, and whether to open a fixed switch of the equalizing valve is determined according to the differential pressure opening degree;

[0011] determine a frequency band sound intensity rise reason according to a valve block pressure change and an acoustic pulse cluster meeting a judgment condition, and adjust a maintenance detection cycle, an initial detection cycle, or a valve block replacement accordingly;

[0012] determine a valve block temperature fluctuation condition according to the valve block temperature rise rate to determine a risk of insufficient regeneration of molecular sieve in the adsorption tower, and adjust a flushing stage timing and the initial adsorption time length in the equalizing trigger condition according to the valve block temperature fluctuation condition.

[0013] Further, the process of dynamically calibrating the adsorption pressure threshold according to the change trend includes:

[0014] when the frequency band sound intensity is detected to rise and a rise amplitude is greater than or equal to a critical amplitude, the adsorption pressure threshold is lowered according to a product of a sound intensity coefficient and the rise amplitude and the frequency band sound intensity;

[0015] when the frequency band sound intensity is not detected to rise or the rise amplitude is less than the critical amplitude, the equalizing valve in the valve block is opened according to the equalizing trigger condition.

[0016] Further, the equalizing trigger condition is to open the equalizing valve in the valve block after the initial adsorption time length after the adsorption pressure of the adsorption tower reaches the adsorption pressure threshold.

[0017] Further, the process of adjusting the valve closing strategy in the valve block according to the valve acoustic features includes:

[0018] acquire a valve acoustic feature at a determined valve acoustic feature sampling point, the valve acoustic feature being an amplitude ratio of a pressure reflection wave of an acoustic signal generated at a valve closing moment;

[0019] The actual amplitude ratio of the pressure reflected wave with a characteristic frequency greater than the fixed frequency is compared with the standard amplitude ratio, and whether the reflected wave amplitude is out of limit is determined according to the comparison result.

[0020] Further, when the reflected wave amplitude is in the normal range, the valve closing strategy of the valve block is determined as one-step hard closing strategy, and when the reflected wave amplitude is out of limit, the valve closing strategy in the valve block is adjusted to two-step soft closing strategy.

[0021] Further, when the equalizing valve in the valve block is determined to be opened, the final opening degree of the equalizing valve is determined according to the acoustic turbulence index, the pressure difference opening degree and the valve block temperature rise rate;

[0022] If the acoustic turbulence index is greater than the strong turbulence evaluation value, the final opening degree is reduced by the acoustic index percentage; if the valve block temperature rise rate is greater than the temperature rise evaluation value, the final opening degree is increased by the temperature rise percentage.

[0023] Further, the pressure difference opening degree is compared with the difference value evaluation value, and when the pressure difference opening degree is greater than the difference value evaluation value, the fixed switch of the equalizing valve is opened.

[0024] Further, the process of determining the reason for the increase of the frequency band sound intensity includes determining the reason for the increase of the frequency band sound intensity according to the change of the valve block pressure and the acoustic pulse cluster meeting the determination condition;

[0025] When the change amplitude of the valve block pressure in the initial detection period is less than or equal to a first standard value, it is determined that the valve block pressure change is slight.

[0026] When the change amplitude is greater than the first standard value and less than or equal to a second standard value, it is determined that the valve block pressure change is moderate, and when the change amplitude is greater than the second standard value, it is determined that the valve block pressure change is serious.

[0027] Further, when the valve block pressure change is slight and the acoustic pulse cluster meeting the determination condition is detected, the reason for the increase of the frequency band sound intensity is micro-cracks in the connecting structure, and the maintenance detection period is adjusted.

[0028] When the valve block pressure change is moderate, the reason for the increase of the frequency band sound intensity is that the internal cylinder or piston of the valve wears out to cause pipeline or joint leakage, and the initial detection period is adjusted.

[0029] When the valve block pressure change is serious, the reason for the increase of the frequency band sound intensity is that the valve action is frequent or the compressed gas flow is large and the impact is intense, causing the valve connecting structure to break, and the valve block is replaced for inspection.

[0030] Further, the temperature change acceleration is calculated in real time according to the calculated valve block temperature rise rate, and if the temperature change acceleration is greater than the standard acceleration for two consecutive minutes, it is determined that there is a risk of insufficient regeneration, and the flushing stage time sequence and the initial adsorption time length are extended.

[0031] Compared with the existing technology, the beneficial effect of the present invention is that in the traditional PSA system, the dispersed arrangement of valves leads to complex pipelines, large pressure drop and high energy consumption. The present invention simplifies the system structure, improves control accuracy, and reduces energy consumption by integrating several valves (such as intake valves, exhaust valves, and equalizing valves) into one valve block, and optimizes gas flow through internal flow channel design, reduces pressure drop and leakage, and improves system efficiency and reliability.

[0032] Furthermore, the traditional method only uses pressure signals to judge the valve state. The present method reflects the degree of cylinder wear by obtaining the frequency band sound intensity change trend of the acoustic characteristics of the valve block, and predicts the working state of the valve block. When the sound intensity increase in a specific frequency band is detected, it may indicate that there is a risk of cylinder wear or valve leakage in the valve block. By lowering the adsorption pressure threshold that needs to be reached in the adsorption tower to reduce the valve block pressure caused by high-pressure gas flowing through the valve block, valve block failure can be avoided. Lowering the adsorption pressure threshold in advance can prevent gas blowby in the valve block, which leads to a decrease in the purity of the produced gas product. At the same time, comparing the increased amplitude with the critical amplitude avoids the situation where the working state of the valve block is misjudged due to the sound intensity fluctuation in the frequency band, thereby increasing the adaptability of the pressure swing adsorption to produce gas products after the pressure swing adsorption valve setting is combined and improved in the application scenario of the present invention where the valve is integrated into the valve block.

[0033] Furthermore, the valve block of the present invention is integrated with several valves and the several valves need to be continuously opened and closed during the pressure swing adsorption process. Over a long period of time, it is easy to accumulate structural impacts on the valve structure, resulting in damage to the valve seat sealing surface or stuck valve core fragments. The method collects the valve acoustic characteristics at the valve acoustic characteristic sampling point, determines whether it is necessary to adjust the valve closing strategy in the valve block according to the valve acoustic characteristics, and adjusts the original one-step hard closing strategy in the valve block to a two-step soft closing strategy. The two-step soft closing strategy can reduce more than half of the original structural impact generated by the one-step hard closing strategy, prevent the several valves in the valve block from accumulating excessive structural impacts, and cause valve seat damage. Compared with traditional vibration analysis, the sensitivity is higher, the sensitivity of detecting dynamic changes of the valve block is improved, and the stability of the pressure swing adsorption production process is increased.

[0034] Furthermore, the prior art simply adjusts the valve opening according to the pressure difference, and is unable to respond to changes in the airflow structure and perform thermal compensation for changes in the valve block temperature. The present method characterizes the airflow chaos in the valve block through the acoustic turbulence index TI, determines the final opening of the equalizing valve based on the acoustic turbulence index TI, the pressure difference opening and the valve block temperature rise rate, and performs multi-physical field coordinated control on the equalizing stage of the pressure swing adsorption, thereby increasing the applicability of the compact integrated valve block system with high-frequency switching of the present invention. At the same time, when the present method determines that the pressure difference between the first adsorption tower and the second adsorption tower is large, the fixed switch of the equalizing valve in the valve block is opened, and the equalizing airflow impact borne by the equalizing valve in the equalizing stage can be adjusted through the movable equalizing valve so that the impact on the equalizing valve is not too large.

[0035] Furthermore, the method combines pressure and acoustics to determine the cause of the increased sound intensity in the frequency band. When an acoustic pulse cluster that meets the judgment conditions is detected and there is no obvious change in the valve block pressure, the cause is determined to be microcracks in the connecting structure. When the valve block pressure changes moderately, the cause is determined to be internal wear of the valve leading to leakage in the pipeline or joint. When the valve block pressure changes severely, the cause is determined to be a break in the valve connecting structure. Corresponding measures are taken according to the determined causes. The method increases the intelligence and automation level of the pressure swing adsorption production process by comprehensively monitoring and analyzing the integrated valve block.

[0036] Furthermore, the adsorption capacity of the adsorbate in the air on the adsorbent in the adsorption tower increases with the increase of the partial pressure of the adsorbate and decreases with the increase of the adsorption temperature. The flow friction of the compressed air flow in the valve block after compression will affect the temperature of the valve block. The temperature fluctuation of the valve block has a lag correlation with the regeneration residual amount of the molecular sieve arranged in the adsorption tower. The method monitors the temperature changes in the oxygen production process in real time, judges the risk of insufficient regeneration of the molecular sieve according to the feedback data of the temperature sensor, and automatically adjusts the operating parameters in the pressure swing adsorption process, thereby effectively ensuring the regeneration effectiveness of the molecular sieve after desorption and backwashing, thereby improving the life of the molecular sieve, reducing the impact of temperature on the desorption and backwashing regeneration of the molecular sieve, reducing the product quality fluctuation of the gas product produced by pressure swing adsorption, increasing the accuracy of pressure swing adsorption production, and realizing adsorption of the adsorbent at low temperature and high pressure and desorption and regeneration at high temperature and low pressure, thereby achieving the adsorption and regeneration cycle of the adsorbent, and further achieving the purpose of continuous gas separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A flow chart of a combined improvement method for pressure swing adsorption valve settings according to an embodiment of the present invention;

[0038] Figure 2 Schematic diagram of a device for producing gas by pressure swing adsorption in an embodiment of the present invention;

[0039] Figure 3 This is a main structural diagram of the valve block in an embodiment of the present invention;

[0040] Figure 4 Schematic diagram of the arrangement of the pressure equalizing valve in the pressure equalizing passage within the valve block in an embodiment of the present invention.

[0041] In the figure: 1-filter, 2-compressor, 3-flow meter, 4-pressure gauge, 5-valve block, 61-first adsorption tower, 62-second adsorption tower, 7-gas storage tank, 8-pressure reducing valve, 9-oxygen analyzer, 10-solenoid valve, 11-pressure sensor, 12-controller, 13-equalizing valve, 14-equalizing spring. DETAILED DESCRIPTION

[0042] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0043] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0044] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside", and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0045] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0046] See also Figures 1-4 As shown, Figure 1 A flow chart of a combined improvement method for pressure swing adsorption valve settings according to an embodiment of the present invention; Figure 2 Schematic diagram of a device for producing gas by pressure swing adsorption in an embodiment of the present invention; Figure 3 This is a main structural diagram of a pressure swing adsorption valve assembly according to an embodiment of the present invention; Figure 4 Schematic diagram of the arrangement of the pressure equalizing valve in the pressure equalizing passage within the valve block in an embodiment of the present invention.

[0047] The present invention provides a combined improvement method for pressure swing adsorption valve settings, comprising:

[0048] Step S1, integrating a plurality of pressure swing adsorption valves in the pressure swing adsorption system into a valve block, and connecting the valve block to other equipment in the pressure swing adsorption system;

[0049] Step S2: Acquire the valve block acoustic characteristics of the valve block according to the initial detection period, determine the change trend of the frequency band sound intensity based on the valve block acoustic characteristics, dynamically calibrate the adsorption pressure threshold according to the change trend, or trigger the adsorption tower to switch and open the equalizing valve in the valve block according to the equalizing pressure trigger condition;

[0050] Step S3, determining valve acoustic characteristic sampling points according to the pressure equalization triggering condition, obtaining valve acoustic characteristics of several valves in the valve block at the determined valve acoustic characteristic sampling points, and adjusting the valve closing strategy in the valve block according to the valve acoustic characteristics;

[0051] Step S4, when the adsorption tower is triggered to switch and open the equalizing valve in the valve block, the final opening of the equalizing valve is determined according to the acoustic turbulence index, the pressure differential opening of the adsorption tower, and the temperature rise rate of the valve block, and whether to open the fixed switch of the equalizing valve is determined according to the pressure differential opening;

[0052] Step S5, determining the cause of the increase in sound intensity in the frequency band based on the change in valve block pressure and the acoustic pulse clusters that meet the determination criteria, and adjusting the maintenance and inspection cycle or the initial inspection cycle or replacing the valve block accordingly;

[0053] Step S6, determining the valve block temperature fluctuation according to the valve block temperature rise rate to determine the risk of insufficient regeneration of the molecular sieve in the adsorption tower, and adjusting the flushing phase timing and the initial adsorption time in the pressure equalization trigger condition according to the valve block temperature fluctuation.

[0054] PSA refers to Pressure Swing Adsorption (PSA) technology. To ensure continuous and uninterrupted gas output during the PSA process, one tower in a dual-tower system is in a high-pressure adsorption sequence while the other tower is in a low-pressure desorption sequence.

[0055] In this embodiment, a high-purity oxygen product is produced by pressure swing adsorption. The instruments involved in the preparation process include a filter 1, a compressor 2, a flow meter 3, a pressure gauge 4, a valve block 5, a first adsorption tower 61, a second adsorption tower 62, a gas storage tank 7, a pressure reducing valve 8, an oxygen analyzer 9, a solenoid valve 10, a pressure sensor 11, and a controller 12.

[0056] Among them, the controller 12 is used to control the working status of the valve block 5 and the compressor 2, and receive detection signals from the oxygen analyzer 9 and the pressure sensor 11; the valve block 5 is equipped with an air inlet valve, an air outlet valve, an exhaust valve and a pressure equalizing valve 13, which are respectively connected to the air inlet, air outlet, exhaust port and pressure equalizing port of the first adsorption tower 61 and the second adsorption tower 62, and the pressure equalizing valve 13 is provided with a fixed switch and is connected to a pressure equalizing spring 14.

[0057] In this embodiment, the working stage cycle sequence of the adsorption tower is high-pressure adsorption stage, pressure drop stage, desorption backwash stage, and pressure rise stage. The cycle sequence of the working stages includes:

[0058] Step Z1: The raw air is pressurized by the air compressor and enters the adsorption tower from the bottom air inlet. The impurities in the raw air are adsorbed by the adsorbent in the tower, and high-purity oxygen is discharged from the adsorption tower outlet.

[0059] Step Z2, the adsorption tower enters the equalizing pressure drop stage, and the adsorption tower is connected to the equalizing pressure port of another adsorption tower in the equalizing pressure rise stage to reduce the pressure in the tower;

[0060] Step Z3, vacuuming, depressurizing and backwashing the adsorption tower to desorb the impurity gas adsorbed by the adsorbent, and the impurity gas is discharged from the exhaust port through a vacuum pump;

[0061] Step Z4, the adsorption tower enters the equalization pressure rising stage, the adsorption tower is connected to another adsorption tower in the equalization pressure falling stage, and after the equalization pressure rising is completed, the pressure in the tower is increased to proceed to step Z1;

[0062] Step Z5, loop steps Z1 to Z4.

[0063] Specifically, in traditional PSA systems, the dispersed arrangement of valves leads to complex pipelines, large pressure drop, and high energy consumption. The present invention simplifies the system structure, improves control accuracy, and reduces energy consumption by integrating several valves (such as intake valves, exhaust valves, and pressure equalizing valves) into one valve block. It also optimizes gas flow through internal flow channel design, reduces pressure drop and leakage, and improves system efficiency and reliability.

[0064] The acoustic characteristics of the valve block and valve are obtained by dynamically calibrating the adsorption pressure threshold driven by acoustic characteristics.

[0065] Using an acoustic pressure sensor to perform acoustic testing on the valve block according to an initial testing cycle to obtain the acoustic characteristics of the valve block, the acoustic characteristics of the valve block being the acoustic energy of the valve block in a number of specific frequency bands, and determining a change trend of the frequency band sound intensity based on the acoustic energy of the number of specific frequency bands;

[0066] In implementation, the sound intensity in the frequency band can be obtained by multiplying the square of the sound pressure by the frequency spectrum density; preferably, the specific frequency band is 1.2 to 1.8 kHz.

[0067] When it is detected that the sound intensity in the frequency band increases and the increase amplitude is greater than or equal to the critical amplitude, the adsorption pressure threshold is lowered in advance;

[0068] Specifically, the reduction amount ΔP of the adsorption pressure threshold is calculated as follows: sound intensity coefficient × increase amplitude × current frequency band sound intensity, where the increase amplitude is the ratio of the increase in frequency band sound intensity of the specific frequency band to the frequency band sound intensity. The unit of the sound intensity coefficient is MPa / dB, the unit of the adsorption pressure threshold is MPa, and the unit of the frequency band sound intensity is dB.

[0069] When no increase in the sound intensity in the frequency band is detected or the increase amplitude is less than the critical amplitude, the adsorption tower is switched to determine the opening of the pressure equalizing valve according to the pressure equalizing trigger condition;

[0070] Specifically, the pressure equalization triggering condition is to open the pressure equalizing valve in the valve block after the adsorption pressure of the adsorption tower reaches the adsorption pressure threshold for the initial adsorption time.

[0071] The critical amplitude is 5%, the sound intensity coefficient is 0.01-0.05 MPa / dB, and the sound intensity coefficient in this embodiment is 0.03 MPa / dB.

[0072] Specifically, the traditional method only uses pressure signals to judge the valve state. The present method reflects the degree of cylinder wear by obtaining the frequency band sound intensity change trend of the acoustic characteristics of the valve block, and predicts the working state of the valve block. When the sound intensity increase in a specific frequency band is detected, it may indicate that there is a risk of cylinder wear or valve leakage in the valve block. By lowering the adsorption pressure threshold that needs to be reached in the adsorption tower to reduce the valve block pressure caused by high-pressure gas flowing through the valve block, valve block failure can be avoided. Lowering the adsorption pressure threshold in advance can prevent gas blowby in the valve block, which leads to a decrease in the purity of the produced gas product. At the same time, comparing the increased amplitude with the critical amplitude avoids the situation where the working state of the valve block is misjudged due to the sound intensity fluctuation in the frequency band, thereby increasing the adaptability of the pressure swing adsorption to produce gas products after the pressure swing adsorption valve setting is combined and improved in the application scenario of the present invention where the valve is integrated into the valve block.

[0073] When the adsorption tower switching is triggered, the outlet valves of the two adsorption towers are switched from open to closed, and the determined valve closing moment is defined as the valve acoustic characteristic sampling point;

[0074] The valve acoustic feature is obtained at a determined valve acoustic feature sampling point, and the valve closing strategy in the valve block is adjusted. The valve acoustic feature is the amplitude ratio of the pressure reflection wave of the acoustic signal generated at the moment of valve closing:

[0075] During implementation, the acoustic signal of the valve block is collected by a high-frequency dynamic pressure sensor to identify the pressure reflection wave generated at the moment the valve is closed. The high-frequency dynamic pressure sensor is respectively set at 50 mm upstream and downstream of the valve block;

[0076] Acquiring an incident wave peak value detected by a high-frequency dynamic pressure sensor located upstream of the valve block and a reflected wave peak value detected by a high-frequency dynamic pressure sensor located downstream of the valve block;

[0077] If the actual amplitude ratio of the pressure reflection wave with a characteristic frequency greater than the fixed frequency is less than or equal to the standard amplitude ratio, it is determined that the amplitude of the reflection wave is within the normal range, and the valve closing strategy of the valve block is determined to be a one-step hard closing strategy;

[0078] If the actual amplitude ratio of the pressure reflection wave with a characteristic frequency greater than the fixed frequency is greater than the standard amplitude ratio, it is determined that the reflection wave amplitude exceeds the limit, and the valve closing strategy in the valve block is adjusted to adopt a two-step soft closing strategy.

[0079] Specifically, the two-step soft closing strategy is to first close the outlet valve to 50% valve opening, and then fully close the outlet valve after a delay of 2ms.

[0080] The fixed frequency is 5 kHz, the amplitude ratio is the ratio of the reflected wave peak to the incident wave peak, and the standard amplitude ratio is 0.8.

[0081] Specifically, the valve block of the present invention is integrated with several valves, and the several valves need to be continuously opened and closed during the pressure swing adsorption process. Over a long period of time, it is easy to accumulate structural impacts on the valve structure, resulting in damage to the valve seat sealing surface or stuck valve core fragments. The method collects the valve acoustic characteristics at the valve acoustic characteristic sampling point, and determines whether it is necessary to adjust the valve closing strategy in the valve block according to the valve acoustic characteristics, and adjusts the original one-step hard closing strategy in the valve block to a two-step soft closing strategy. The two-step soft closing strategy can reduce more than half of the original structural impact generated by the one-step hard closing strategy, and prevent the several valves in the valve block from accumulating excessive structural impacts, resulting in valve seat damage. Compared with traditional vibration analysis, the sensitivity is higher, the sensitivity of detecting dynamic changes of the valve block is improved, and the stability of the pressure swing adsorption production process is increased.

[0082] When determining to open the pressure equalizing valve in the valve block, the final opening of the pressure equalizing valve is determined according to the acoustic turbulence index TI, the pressure difference opening and the valve block temperature rise rate;

[0083] During implementation, the current pressure difference between the first adsorption tower and the second adsorption tower is calculated and recorded as the pressure differential opening, the valve block temperature rise rate detected by the temperature sensor within a unit time is calculated, and the acoustic turbulence index TI is calculated by the spectral entropy value of the sound signal in the 20-200 Hz frequency band;

[0084] Specifically, the acoustic signal in the 20-200 Hz frequency band is decomposed by wavelet packet decomposition into several sub-generation energy entropies Ei, TI = -∑(Ei / E)·log(Ei / E), where E is the total energy of the acoustic signal;

[0085] Final opening = differential pressure opening × (1-TI / 10) + 8% (1 + valve block temperature rise rate);

[0086] Among them, if the acoustic turbulence index is greater than the strong turbulence rating value, the final opening is reduced according to the acoustic index percentage; if the valve block temperature rise rate is greater than the temperature rise rating value, the final opening is increased according to the temperature rise percentage.

[0087] Specifically, the strong turbulence rating value is 7, the temperature rise rating value is 1°C / min, the acoustic index percentage is 20%, and the temperature rise percentage is 5%.

[0088] When the pressure difference opening is greater than the difference evaluation value, the fixed switch of the pressure equalizing valve is opened, and the pressure equalizing valve moves under the action of the pressure difference;

[0089] The difference evaluation value is a preset value set according to historical data of the pressure difference between the first adsorption tower and the second adsorption tower.

[0090] Specifically, the prior art simply adjusts the valve opening according to the pressure difference, and is unable to respond to changes in the airflow structure and perform thermal compensation for changes in the valve block temperature. The present method characterizes the airflow chaos in the valve block through the acoustic turbulence index TI, determines the final opening of the equalizing valve based on the acoustic turbulence index TI, the pressure difference opening and the valve block temperature rise rate, and performs multi-physical field coordinated control on the equalizing stage of the pressure swing adsorption, thereby increasing the applicability of the compact integrated valve block system with high-frequency switching of the present invention. At the same time, when the present method determines that the pressure difference between the first adsorption tower and the second adsorption tower is large, the fixed switch of the equalizing valve in the valve block is opened, and the equalizing airflow impact borne by the equalizing valve in the equalizing stage can be adjusted through the movable equalizing valve so that the impact on the equalizing valve is not too large.

[0091] A pressure sensor is used to detect the valve block pressure applied to the valve block, and the cause of the increase in sound intensity in the frequency band is determined based on the change in the valve block pressure and the acoustic pulse cluster that meets the determination conditions;

[0092] When an acoustic pulse cluster meeting the judgment conditions is detected and the amplitude of the change in the valve block pressure within the initial detection period is less than or equal to the first standard value, it is determined that the valve block pressure change is slight, the increase in the sound intensity in the frequency band is caused by microcracks in the connection structure, and the maintenance and inspection cycle is adjusted;

[0093] Specifically, the acoustic pulse cluster that meets the judgment conditions is a burst high-frequency signal with an interval of less than 100ms; during implementation, the current maintenance and repair cycle is compressed to 30%.

[0094] If the change amplitude is greater than the first standard value and less than or equal to the second standard value, it is determined that the valve block pressure change is moderate, and the reason for the increase in the sound intensity in the frequency band is that the cylinder or piston inside the valve is worn, resulting in leakage in the pipeline or joint, and the initial detection cycle is adjusted;

[0095] Specifically, the initial detection period is reduced according to the ratio of the first standard value to the variation amplitude;

[0096] If the variation is greater than the second standard value, it is determined that the pressure variation of the valve block is serious. The reason for the increase in the sound intensity in the frequency band is that the valve connection structure is broken due to frequent valve operation or large flow of compressed gas and severe impact. The valve block should be replaced and inspected.

[0097] Among them, the first standard value is 5% and the second standard value is 15%.

[0098] Specifically, this method combines pressure and acoustics to determine the cause of the increased sound intensity in the frequency band. When an acoustic pulse cluster that meets the judgment conditions is detected and there is no obvious change in the valve block pressure, the cause is determined to be microcracks in the connecting structure. When the valve block pressure changes moderately, the cause is determined to be internal wear of the valve causing leakage in the pipeline or joint. When the valve block pressure changes severely, the cause is determined to be a break in the valve connecting structure. Corresponding measures are taken according to the determined causes. This method increases the intelligence and automation level of the pressure swing adsorption production process by comprehensively monitoring and analyzing the integrated valve block.

[0099] Determine the risk of insufficient regeneration based on the temperature fluctuation of the valve block, and adjust the flushing phase timing and the initial adsorption duration during the pressure swing adsorption oxygen production process;

[0100] The temperature change acceleration is calculated in real time based on the calculated valve block temperature rise rate. If the temperature change acceleration is greater than the standard acceleration for two consecutive minutes, it is determined that there is a risk of insufficient regeneration, and the flushing phase sequence and the initial adsorption time are extended;

[0101] Specifically, the flushing phase timing and the initial adsorption time are extended according to the ratio of the temperature change acceleration to the standard acceleration;

[0102] The standard acceleration is 0.1°C / s².

[0103] Specifically, the adsorption capacity of the adsorbate in the air on the adsorbent in the adsorption tower increases with the increase of the partial pressure of the adsorbate and decreases with the increase of the adsorption temperature. The flow friction of the compressed air flow in the valve block after compression will affect the temperature of the valve block. There is a lag correlation between the temperature fluctuation of the valve block and the regeneration residual amount of the molecular sieve arranged in the adsorption tower. The method monitors the temperature changes in the oxygen production process in real time, judges the risk of insufficient regeneration of the molecular sieve according to the feedback data of the temperature sensor, and automatically adjusts the operating parameters in the pressure swing adsorption process, effectively ensuring the regeneration effectiveness of the molecular sieve after desorption and backwashing, thereby improving the life of the molecular sieve, reducing the impact of temperature on the desorption and backwashing regeneration of the molecular sieve, reducing the product quality fluctuation of the gas product produced by pressure swing adsorption, increasing the accuracy of pressure swing adsorption production, and realizing adsorption of the adsorbent at low temperature and high pressure and desorption and regeneration at high temperature and low pressure, so as to achieve the adsorption and regeneration cycle of the adsorbent, and further achieve the purpose of continuous separation of gases.

[0104] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

[0105] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A combined improvement method for pressure swing adsorption valve setting, characterized in that: include: Integrating a plurality of pressure swing adsorption valves in the pressure swing adsorption system into a valve block, and connecting the valve block to other equipment in the pressure swing adsorption system; Acquiring the valve block acoustic characteristics of the valve block according to the initial detection period, determining the change trend of the frequency band sound intensity based on the valve block acoustic characteristics, and dynamically calibrating the adsorption pressure threshold according to the change trend or triggering the adsorption tower to switch and open the equalizing valve in the valve block according to the equalizing pressure triggering condition; determining valve acoustic feature sampling points according to the pressure equalization triggering condition, acquiring valve acoustic features of a plurality of valves in the valve block at the determined valve acoustic feature sampling points, and adjusting a valve closing strategy in the valve block according to the valve acoustic features; When the adsorption tower is triggered to switch on the equalizing valve in the valve block, the final opening of the equalizing valve is determined according to the acoustic turbulence index, the pressure differential opening of the adsorption tower, and the temperature rise rate of the valve block, and whether to open the fixed switch of the equalizing valve is determined according to the pressure differential opening; Determine the cause of the increase in sound intensity in the frequency band based on the change in valve block pressure and the acoustic pulse clusters that meet the judgment conditions, and adjust the maintenance and repair cycle or initial inspection cycle or replace the valve block accordingly; The valve block temperature fluctuation is determined according to the valve block temperature rise rate to judge the risk of insufficient regeneration of the molecular sieve in the adsorption tower, and the flushing phase timing and the initial adsorption time in the pressure equalization trigger condition are adjusted according to the valve block temperature fluctuation.

2. The combined improvement method for pressure swing adsorption valve setting according to claim 1 is characterized in that: The process of dynamically calibrating the adsorption pressure threshold according to the change trend includes: When it is detected that the sound intensity of the frequency band increases and the increase amplitude is greater than or equal to the critical amplitude, the adsorption pressure threshold is reduced according to the product of the sound intensity coefficient, the increase amplitude and the sound intensity of the frequency band; When no increase in the sound intensity in the frequency band is detected or the increase amplitude is less than the critical amplitude, the adsorption tower is switched to determine the opening of the pressure equalizing valve in the valve block according to the pressure equalizing trigger condition.

3. The combined improvement method for pressure swing adsorption valve setting according to claim 2 is characterized in that: The pressure equalization triggering condition is to open the pressure equalization valve in the valve block after the adsorption pressure of the adsorption tower reaches the adsorption pressure threshold value and the initial adsorption time.

4. The combined improvement method for pressure swing adsorption valve setting according to claim 1 is characterized in that: The process of adjusting the valve closing strategy in the valve block according to the valve acoustic characteristics includes: Acquiring a valve acoustic feature at a determined valve acoustic feature sampling point, wherein the valve acoustic feature is an amplitude ratio of a pressure reflection wave of an acoustic signal generated at the moment the valve is closed; The actual amplitude ratio of the pressure reflection wave with a characteristic frequency greater than the fixed frequency is compared with the standard amplitude ratio, and whether the reflection wave amplitude exceeds the limit is determined based on the comparison result.

5. The combined improvement method for pressure swing adsorption valve setting according to claim 4 is characterized in that: If the actual amplitude ratio is less than or equal to the standard amplitude ratio, it is determined that the reflected wave amplitude is within a normal range; if the actual amplitude ratio is greater than the standard amplitude ratio, it is determined that the reflected wave amplitude exceeds the limit.

6. The combined improvement method for pressure swing adsorption valve setting according to claim 4 is characterized in that: When the reflected wave amplitude is within a normal range, the valve closing strategy of the valve block is determined to be a one-step hard closing strategy, and when the reflected wave amplitude exceeds a limit, the valve closing strategy in the valve block is adjusted to a two-step soft closing strategy.

7. The combined improvement method for pressure swing adsorption valve setting according to claim 2, characterized in that: When determining whether to open the equalizing valve in the valve block, the final opening of the equalizing valve is determined based on the acoustic turbulence index, the differential pressure opening, and the temperature rise rate of the valve block; Among them, if the acoustic turbulence index is greater than the strong turbulence rating value, the final opening is reduced according to the acoustic index percentage; if the valve block temperature rise rate is greater than the temperature rise rating value, the final opening is increased according to the temperature rise percentage.

8. The combined improvement method for pressure swing adsorption valve arrangement according to claim 6, characterized in that: The pressure difference opening is compared with the difference evaluation value, and when the pressure difference opening is greater than the difference evaluation value, the fixed switch of the pressure equalizing valve is opened.

9. The combined improvement method for pressure swing adsorption valve setting according to claim 1, characterized in that: Determine the cause of the increase in sound intensity in the frequency band based on the change in valve block pressure and the acoustic pulse cluster that meets the judgment conditions; The change amplitude of the valve block pressure in the initial detection period is less than or equal to the first standard value, and when an acoustic pulse cluster meeting the judgment conditions is detected, the cause of the increase in sound intensity in the frequency band is microcracks in the connection structure, and the maintenance and inspection period is adjusted; When the amplitude of the change is greater than the first standard value and less than or equal to the second standard value, the reason for the increase in the sound intensity in the frequency band is that the cylinder or piston inside the valve is worn, resulting in leakage in the pipeline or joint, and the initial detection cycle is adjusted; When the variation amplitude is greater than the second standard value, the reason for the increase in the sound intensity in the frequency band is that the valve connection structure is broken due to frequent valve action or large impact of compressed gas flow. The valve block should be replaced and inspected.

10. The combined improvement method for pressure swing adsorption valve setting according to claim 6, characterized in that: The temperature change acceleration is calculated in real time based on the calculated valve block temperature rise rate. If the temperature change acceleration is greater than the standard acceleration for two consecutive minutes, it is determined that there is a risk of insufficient regeneration, and the flushing phase timing and initial adsorption time are extended.

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