Air-suspending oil-free VPSA (Vacuum Pressure Swing Adsorption) oxygen generation system capable of actively recovering residual gas

Abstract

The invention relates to the technical field of pressure swing adsorption (VPSA) gas separation, and discloses an air suspension oil-free VPSA oxygen generation system capable of actively recovering residual gas, which comprises an oxygen generation host module, a gas path switching module, a buffer output module and a central control module. And the gas path switching module is integrated with a tower top pressure-equalizing regulating valve with continuous opening degree regulating capability, a tower bottom pressure-equalizing control valve and a tower bottom gas supplementing assembly independently communicated with the atmosphere. The central control module executes cooperative control based on the real-time pressure difference data: in the pressure equalizing process, the opening degree of a tower top pressure equalizing regulating valve and the real-time pressure difference are controlled to be subjected to inverse correlation dynamic regulation, and the flow speed is limited to prevent bed pulverization; synchronously opening a tower bottom pressure equalizing control valve to recover bottom dead gap gas potential energy; in the initial stage of pressure increasing and decreasing, the natural pressure difference between the adsorption tower and the atmosphere is used for controlling the air supply assembly to achieve unpowered auxiliary air intake and exhaust. The system operation energy consumption can be effectively reduced, molecular sieve pulverization is prevented, and the oxygen production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of pressure swing adsorption gas separation technology, specifically to an oil-free VPSA oxygen generation system for active recovery of residual gas. Background Technology

[0002] Vacuum pressure swing adsorption (VPSA) oxygen generation technology utilizes the selective adsorption characteristics of molecular sieves to separate oxygen from the air through periodic pressure adsorption and vacuum desorption cycles. Its advantages, such as rapid start-up and high degree of automation, have led to its widespread application in industrial and medical oxygen supply fields. In actual operation, to improve oxygen recovery rates, the system typically performs pressure equalization operations during the pressure switching intervals of the adsorption tower.

[0003] However, existing pressure equalization control logic often uses shut-off valves with only on / off functions. At the initial moment of pressure equalization, there is a significant pressure gradient between the high-pressure and low-pressure towers. The instantaneous full opening of the valve causes a surge in airflow velocity within the pipeline. This uncontrolled high-speed airflow impact directly affects the molecular sieve bed, easily leading to relative displacement and friction of adsorbent particles, and even causing bed "boiling." Long-term operation can cause molecular sieve pulverization, which can block the airflow channels and severely affect system lifespan and separation performance.

[0004] Furthermore, conventional VPSA processes have limitations in energy management, primarily relying on power equipment such as Roots blowers or vacuum pumps for forced delivery throughout the process, failing to effectively utilize the natural pressure difference between the internal pressure of the adsorption tower and the external atmospheric pressure. During the transition from positive pressure to vacuum, or vice versa, existing systems often directly activate the power equipment, neglecting to utilize the pressure difference with the atmosphere for passive venting and depressurization or natural intake and pressurization. This results in the power equipment operating under inefficient conditions for extended periods. Simultaneously, the pressure potential energy of the gas trapped in the dead space at the bottom of the adsorption tower is typically directly vented or left idle, lacking an effective recovery mechanism, thus limiting the overall energy efficiency improvement of the unit. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an oil-free VPSA oxygen generation system with active residual gas recovery, which solves the problems of easy pulverization of molecular sieves caused by airflow impact during pressure equalization switching in existing VPSA oxygen generation systems, and high system operating energy consumption due to insufficient utilization of natural pressure difference and residual gas potential energy at the bottom of the tower.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an oil-free VPSA oxygen generation system with active residual gas recovery, comprising: The oxygen generator module is equipped with a first adsorption tower and a second adsorption tower arranged in parallel. The first adsorption tower and the second adsorption tower are filled with molecular sieves. The gas power input end of the oxygen generator module is connected to an external gas power device to introduce compressed air and provide vacuum suction power. The gas path switching module is located in the gas pipeline network of the oxygen generator module. It includes a tower top pressure equalization component, a tower bottom pressure equalization component and a tower bottom gas supply component. It is used to control the gas flow direction, pressure balance and interaction with the external atmosphere inside the system. A buffer output module is connected to the output end of the gas path switching module. It collects the oxygen-enriched air produced by the first adsorption tower or the second adsorption tower through an oxygen buffer tank and stabilizes the output pressure. The central control module connects the sensors and actuators in the oxygen generator module, the gas path switching module and the buffer output module. Based on the collected real-time pressure and current parameters, it coordinates the valve opening change rate of the pressure equalization component (21) at the top of the tower, the on / off timing of the pressure equalization component (22) at the bottom of the tower, and the connection status between the gas supply component (23) at the bottom of the tower and the atmosphere, so as to achieve a smooth transition of internal pressure in the adsorption tower and recovery of residual potential energy.

[0007] Preferably, the tower top pressure equalization assembly includes a tower top pressure equalization pipe, a tower top pressure equalization regulating valve, and an oxygen outlet pipe. The two ends of the tower top pressure equalization pipe are respectively airtightly connected to the top outlets of the first adsorption tower and the second adsorption tower to form a bidirectional gas channel. The tower top pressure equalization regulating valve is connected in series in the middle section of the tower top pressure equalization pipe, and the tower top pressure equalization regulating valve (2102) is configured as an electric regulating valve capable of receiving analog control signals to continuously adjust the valve core opening. The buffer output module is connected in parallel to the top of the first adsorption tower and the second adsorption tower through the oxygen outlet pipe and the tower top pressure equalization pipe.

[0008] Preferably, the bottom pressure equalization assembly includes a bottom gas inlet / outlet pipe, a bottom pressure equalization control valve, and a bottom pressure equalization pipe. The two ends of the bottom gas inlet / outlet pipe are respectively fixedly connected to the bottom gas inlet of the first adsorption tower and the bottom gas inlet of the second adsorption tower to form a communication structure. The two ends of the bottom pressure equalization pipe are respectively connected to the side wall of the bottom gas inlet / outlet pipe. The bottom pressure equalization control valve (2202) is installed on the pipeline path of the bottom pressure equalization pipe (2203) to control the direct connection and cut-off between the bottoms of the two adsorption towers. The gas supply component at the bottom of the tower includes a gas supply branch pipe, a gas supply valve, and a silencer filter assembly. One end of each of the two gas supply branch pipes is connected to the bottom of the first adsorption tower and the second adsorption tower, respectively. The other end of each gas supply branch pipe is fixedly connected to a gas supply valve, and one end of the gas supply valve is fixedly connected to a silencer filter assembly.

[0009] Preferably, the silencer and filter assembly in the bottom gas supply assembly includes a resistive silencer structure and an air filter covering the air inlet end face; the effective flow cross-sectional area of ​​the silencer and filter assembly (2303) is larger than the pipe cross-sectional area of ​​the gas supply branch pipe (2301), and discharges the gas in the tower to the atmosphere when the gas supply valve (2302) is open and the pressure in the adsorption tower is higher than the atmospheric pressure, and filters the external air and draws it into the adsorption tower when the gas supply valve (2302) is open and the pressure in the adsorption tower is lower than the atmospheric pressure.

[0010] Preferably, the sensor devices connected to the central control module include: The first pressure transmitter is installed at the top of the first adsorption tower and is used to collect the instantaneous absolute pressure value inside the first adsorption tower. The second pressure transmitter is installed at the top of the second adsorption tower and is used to collect the instantaneous absolute pressure value inside the second adsorption tower. The environmental pressure monitoring unit is used to collect real-time atmospheric pressure data of the environment in which the equipment is located. A current sensing element is connected in series in the power supply circuit of the external gas power equipment to detect the load current signal.

[0011] Preferably, the central control module is configured to execute active pressure equalization control logic for the residual gas at the top of the tower: When the adsorption cycle ends, the central control module calculates the real-time pressure difference between the first adsorption tower and the second adsorption tower; When the real-time pressure difference is greater than the preset start-up pressure difference threshold, the central control module sends an opening command to the tower top equalizing regulating valve; During the pressure equalization process, the opening of the pressure equalization regulating valve (2102) at the top of the tower is dynamically adjusted based on the real-time pressure difference data calculated in real time, so that the opening of the pressure equalization regulating valve (2102) at the top of the tower is inversely correlated with the real-time pressure difference data, thereby limiting the gas flow rate in the initial large pressure difference stage to a preset range to prevent the molecular sieve bed from pulverizing.

[0012] Preferably, the central control module is configured to perform valve opening adjustment based on a function model, and the target opening of the tower top equalizing regulating valve (2102) is set as the sum of a preset minimum initial opening and a dynamic opening adjustment amount; The dynamic opening adjustment amount is configured to be proportional to the attenuation ratio of the current real-time pressure difference data relative to the starting pressure difference threshold, until the real-time pressure difference data drops to the cutoff threshold, controlling the tower top equalization regulating valve (2102) to close.

[0013] Preferably, the central control module is configured to execute bypass balance control logic for potential energy exchange at the base of the tower: During the execution of the active pressure equalization control logic, the pressure equalization control valve (2202) at the bottom of the tower is simultaneously controlled to be fully open, so that the gas at the bottom of the high-pressure side adsorption tower bypasses the external gas power equipment and flows directly to the bottom of the low-pressure side adsorption tower. The rate of change of the real-time pressure difference is monitored in real time. When the rate of change is less than a preset slowdown threshold, or when the pressure of the high-pressure side adsorption tower drops to a preset intermediate pressure value, the pressure equalization control valve at the bottom of the tower is closed.

[0014] Preferably, the central control module is configured to execute natural intake and exhaust control logic based on atmospheric pressure difference: For an adsorption tower in the initial stage of depressurization, determine whether its internal pressure is higher than the sum of the real-time atmospheric pressure and the set positive pressure difference of the exhaust gas; if so, control the main process valve group connected to the external gas power equipment to close or remain closed, and open the corresponding gas supply valve to use the pressure difference to discharge the gas in the tower to the atmosphere until the pressure is close to the real-time atmospheric pressure, then close the gas supply valve and switch to the vacuum suction process. For the adsorption tower in the initial stage of pressurization, determine whether its internal pressure is lower than the difference between the real-time atmospheric pressure and the set negative pressure difference for air intake; if so, control the main process valve group connected to the external gas power equipment to close or remain closed, and open the corresponding air supply valve to use the pressure difference to draw external air into the tower until the pressure is close to the real-time atmospheric pressure, then close the air supply valve and switch to the active pressurization process.

[0015] Preferably, the central control module is equipped with a logic interlock program, which includes: during the period when the pressure equalization control valve at the bottom of the tower is open, forcibly locking the gas supply valves corresponding to the first adsorption tower and the second adsorption tower to the closed state; during the period when any gas supply valve is open, forcibly locking the main process valve group between the corresponding adsorption tower and the external gas power equipment to the closed state, or controlling the external gas power equipment to be in the unloading state.

[0016] This invention provides an oil-free VPSA oxygen generation system with active residual gas recovery. It has the following beneficial effects: 1. This invention configures a tower top pressure equalization regulating valve with continuous opening adjustment capability and implements a control strategy inversely correlated with the valve opening and the real-time pressure difference between the two towers. During the initial stage of pressure equalization with a large pressure difference, the valve is forced to maintain a small opening, gradually increasing the opening as the pressure difference decreases. This logic effectively limits the peak gas velocity in the pipeline, avoiding the high-speed airflow impact caused by the instantaneous full opening of traditional on / off valves. It also prevents the molecular sieve bed in the adsorption tower from fluidizing or pulverizing due to airflow disturbance, ensuring the stability of the adsorbent's performance and extending its service life.

[0017] 2. This invention features an independent atmospheric-vented silencing filter and air supply component at the bottom of the adsorption tower. A central control module determines the pressure difference between the tower and atmospheric pressure, controlling the air supply valve to open during the initial stages of pressure increase or decrease in the adsorption tower. This design utilizes natural pressure difference to replace power equipment for passive air intake or exhaust, eliminating the need for the oxygen generator to rely entirely on blowers or vacuum pumps during the pressure balance transition phase. This reduces the operating time of power equipment under inefficient conditions and lowers the overall energy consumption of the system.

[0018] 3. This invention establishes a bypass channel that directly connects the bottoms of the two towers through a tower bottom equalization component. This bypass channel is activated synchronously with the tower top equalization action, allowing the stagnant gas at the bottom of the high-pressure side adsorption tower to be directly introduced into the bottom of the low-pressure side adsorption tower. This enables the recovery of the pressure potential energy and effective components of the gas in the dead space at the bottom of the tower. Without consuming external power, this invention assists the low-pressure tower in quickly completing the initial pressurization, thereby improving the oxygen recovery rate and gas production efficiency of the device. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the system framework of the present invention; Figure 2 This is an electrical connection block diagram of the central control module of the present invention; Figure 3 This is a flowchart of the full-cycle coordinated control based on differential pressure drive according to the present invention; Figure 4 This is a schematic diagram of the opening control characteristic curve of the tower top pressure equalization regulating valve of the present invention; Figure 5 This is a schematic diagram of the main view of the device of the present invention; Figure 6 This is a schematic side view of the device of the present invention.

[0020] Among them, 10, oxygen generator module; 11, first adsorption tower; 12, second adsorption tower; 20, gas path switching module; 21, tower top pressure equalization assembly; 2101, tower top pressure equalization pipeline; 2102, tower top pressure equalization regulating valve; 2103, oxygen outlet pipeline; 22, tower bottom pressure equalization assembly; 2201, tower bottom inlet and outlet gas pipelines; 2202, tower bottom pressure equalization control valve; 2203, tower bottom pressure equalization pipeline; 23, tower bottom gas replenishment assembly; 2301, gas replenishment branch pipeline; 2302, gas replenishment valve; 2303, silencer filter assembly; 30, buffer output module; 3001, oxygen buffer tank; 40, central control module. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see the appendix Figure 1 -Appendix Figure 6 This invention provides an oil-free VPSA oxygen generation system with active residual gas recovery, comprising: The oxygen generator module 10 is equipped with a first adsorption tower 11 and a second adsorption tower 12 arranged in parallel. The first adsorption tower 11 and the second adsorption tower 12 are filled with molecular sieves. The oxygen generator module 10 is connected to an external gas power device to introduce compressed air and provide vacuum suction power. The gas path switching module 20 is installed in the gas pipeline network of the oxygen generator module 10. It includes a tower top pressure equalization component 21, a tower bottom pressure equalization component 22 and a tower bottom gas supply component 23. It is used to control the gas flow direction, pressure balance and interaction with the external atmosphere inside the system. The buffer output module 30 is connected to the output end of the gas path switching module 20 and is used to collect the oxygen-enriched air produced by the first adsorption tower 11 or the second adsorption tower 12 and stabilize the output pressure. The central control module 40 is connected to the sensors and actuators in the oxygen generator module 10, the gas path switching module 20 and the buffer output module 30. It is used to collect pressure and current parameters and control the operation of each component.

[0023] The working principles and technical details of the above modules will be explained in detail below with reference to specific embodiments.

[0024] The oxygen generator module 10 adopts a redundant topology structure with two towers in parallel, specifically including a first adsorption tower 11 and a second adsorption tower 12. Both the first adsorption tower 11 and the second adsorption tower 12 adopt a vertical cylindrical pressure vessel structure, and the material is selected from carbon steel or stainless steel to meet the fatigue strength requirements of alternating positive and negative pressure cycles during pressure swing adsorption. In this embodiment, lithium-based zeolite molecular sieve is preferably used, which has the characteristic of preferentially adsorbing nitrogen gas, while oxygen permeates the bed as the product gas.

[0025] The gas power input terminal of the oxygen generator module 10 is connected to an external gas power device via a pipeline. The gas power device mainly includes an oil-free Roots blower or an oil-free screw air compressor, and a matching water-cooled or air-cooled aftercooler. Before entering the adsorption tower, the compressed air provided by the gas power device is cooled to the optimal operating temperature range of the molecular sieve by the cooler. The bottom interfaces of the first adsorption tower 11 and the second adsorption tower 12 are respectively connected to a vacuum pump via pipelines, which is used to extract the adsorbed saturated nitrogen and discharge it into the atmosphere during the desorption stage, thereby realizing the regeneration of the adsorbent.

[0026] The gas path switching module 20 is located between the oxygen generator module 10 and the external environment. Its physical topology consists of three independent fluid control loops: the top pressure equalization component 21 located at the top of the adsorption tower, the bottom pressure equalization component 22 located at the bottom of the adsorption tower, and the bottom gas supply component 23 located on the branch line at the bottom of the adsorption tower. In order to cooperate with the gas path switching, the gas path switching module 20 also includes a main inlet valve group and a main exhaust valve group connected between the adsorption tower and the gas power equipment, which are used to control the on / off of the main process flow.

[0027] The top pressure equalization assembly 21 establishes a direct bidirectional gas channel between the top gas chambers of the first adsorption tower 11 and the second adsorption tower 12 via the top pressure equalization pipe 2101. Both ends of the top pressure equalization pipe 2101 are airtightly connected to the top outlets of the two adsorption towers via tee fittings. A top pressure equalization regulating valve 2102 is connected in series in the middle section of the top pressure equalization pipe 2101. This valve is configured as an electrically operated regulating valve with bidirectional flow capability and a response time that meets the system switching frequency. The top pressure equalization regulating valve 2102 can adjust the valve core opening according to external control signals and can receive opening signals output by the central control module 40 to continuously adjust the valve core angle, thereby precisely controlling the gas flow rate through the channel, rather than simply performing an on / off function.

[0028] The oxygen outlet pipe 2103 serves as the main collection pipe for oxygen-enriched gas. Its inlet end is connected to the remaining ports of the tee joints at the top of the first adsorption tower 11 and the second adsorption tower 12, respectively. That is, the oxygen outlet pipe 2103 and the tower top equalization pipe 2101 are connected in parallel to the top of the adsorption tower. A one-way valve group is installed on the oxygen outlet pipe 2103. The conduction direction of the one-way valve group is towards the buffer output module 30 to prevent gas backflow.

[0029] The bottom pressure equalization assembly 22 directly connects the bottom inlet of the first adsorption tower 11 to the bottom inlet of the second adsorption tower 12 via the bottom pressure equalization pipe 2203, forming a connected structure. The bottom inlet / outlet pipe 2201 serves as the main airflow channel at the bottom of the adsorption tower, with one end connected to the bottom of the adsorption tower and the other end connected to the gas power equipment. A controlled main process valve group is installed on the bottom inlet / outlet pipe 2201 to control the connection or disconnection between the adsorption tower and the gas power equipment, in order to coordinate with the subsequent gas replenishment logic. Both ends of the bottom pressure equalization pipe 2203 are connected to the side walls of the bottom inlet / outlet pipe 2201.

[0030] The bottom pressure equalization control valve 2202 is installed on the pipeline path of the bottom pressure equalization pipe 2203. This valve is configured as a large-diameter, low-flow-resistance straight-through electric gate valve or butterfly valve. When the bottom pressure equalization control valve 2202 is opened, the bottom of the first adsorption tower 11 and the bottom of the second adsorption tower 12 form a communicating vessel structure, allowing the compressed gas in the high-pressure side adsorption tower to flow directly to the bottom of the low-pressure side adsorption tower through the bottom pressure equalization pipe 2203 without passing through a mechanical compressor.

[0031] Two bottom gas supply components 23 are independently installed in the bottom piping network of the first adsorption tower 11 and the second adsorption tower 12. Each adsorption tower 11 and the second adsorption tower 12 is equipped with a gas supply branch pipe 2301, one end of which is connected to the bottom inlet / outlet gas pipe 2201, and the other end extends to the external space of the equipment. A gas supply valve 2302 is installed on the gas supply branch pipe 2301, serving as an isolation interface between the internal pressure environment of the system and the external atmospheric environment. A silencer filter component 2303 is fixedly connected to the external port of the gas supply valve 2302.

[0032] The silencer filter assembly 2303 employs a resistive silencer structure filled with microporous ceramic or fiber cotton, and is covered with a removable and washable air filter on the air inlet end face. The effective flow cross-sectional area of ​​the silencer filter assembly 2303 is designed to be larger than the cross-sectional area of ​​the air supply branch pipe 2301 to reduce gas flow resistance. This allows the bottom of the adsorption tower to be directly connected to the atmospheric environment when the air supply valve 2302 is open: if the pressure inside the tower is higher than atmospheric pressure, the gas inside the tower is discharged to the atmosphere through the silencer filter assembly 2303; if the pressure inside the tower is lower than atmospheric pressure, outside air is drawn into the tower after being filtered by the silencer filter assembly 2303.

[0033] The aforementioned tower top equalizing pressure regulating valve 2102, tower bottom equalizing pressure control valve 2202, and gas replenishment valve 2302 are all equipped with position feedback sensors to provide real-time feedback to the central control module 40 on the actual opening status of the valve core.

[0034] The buffer output module 30 is located downstream of the gas path switching module 20 and mainly consists of an oxygen buffer tank 3001, a pressure regulating valve assembly, and a precision filter. The oxygen buffer tank 3001 is airtightly connected to the oxygen outlet pipe 2103 of the gas path switching module 20 via an air inlet. The oxygen buffer tank 3001 is designed as a large-capacity pressure vessel with a physical volume of… The design is based on smoothing the flow pulsation during the switching of the adsorption towers. When the first adsorption tower 11 or the second adsorption tower 12 completes adsorption and oxygen production, a high-concentration pulsed oxygen enrichment flow enters the oxygen buffer tank 3001. The gas expands and mixes in the tank, and is transformed into a continuous gas flow with relatively constant pressure and flow rate, which is discharged from the outlet.

[0035] To quantify the pressure-stabilizing function of the oxygen buffer tank 3001 and its support for the system's continuous gas supply capacity, a dynamic pressure balance model within the buffer tank is established. The rate of pressure change within the buffer tank is proportional to the difference between the inflow and outflow mass flow rates, and its physical process follows the following state equation: ; In the formula, express Real-time pressure inside oxygen buffer tank 3001. Represents the universal gas constant. The thermodynamic temperature of the gas inside the container is represented and treated as an isothermal process. This indicates the molar mass of oxygen. Indicates time Real-time pressure inside oxygen buffer tank 3001 This indicates the effective physical volume of oxygen buffer tank 3001. This represents the instantaneous mass flow rate of oxygen-enriched air from the adsorption tower. Indicates time The mass flow rate of oxygen flowing out of the buffer tank This represents the instantaneous mass flow rate of oxygen supplied to the user, which is approximately constant under steady-state conditions.

[0036] The central control module 40 serves as the control core of the entire system. It is connected to the oxygen generator module 10, the gas path switching module 20, and the buffer output module 30 via electrical circuits to realize signal acquisition, processing, and command output.

[0037] For signal acquisition, multiple physical state monitoring elements are configured. The first pressure transmitter is located at the top of the first adsorption tower 11, with its probe extending into the tower or connected to the top gas manifold. It is used to acquire the instantaneous absolute pressure value inside the first adsorption tower 11 in real time, denoted as [insert value here]. The second pressure transmitter is installed at the top of the second adsorption tower 12 to collect the instantaneous absolute pressure value inside the second adsorption tower 12 in real time, denoted as . .

[0038] The output pressure transmitter is installed on the oxygen buffer tank 3001 of the buffer output module 30 to monitor the steady-state pressure output by the system to the user end, denoted as . The environmental pressure monitoring unit is located outside the cabinet of the central control module 40 or at a separate air intake sampling point. It is used to collect the real-time atmospheric pressure of the environment in which the equipment is located, denoted as [missing information]. Data from the environmental pressure monitoring unit is used as a baseline variable in subsequent differential pressure calculations to eliminate the influence of altitude and meteorological conditions on the control logic.

[0039] The current sensing element, specifically a Hall current sensor or a current transformer, is connected in series in the motor power supply circuit of the gas power equipment to detect the load current signal of the motor in real time, denoted as... This signal is used to provide feedback on the mechanical load status of the system.

[0040] The central control module 40 coordinates the actions of the oxygen generator module 10 and the gas path switching module 20 based on a preset logical timing sequence and real-time sensor data. The control process is executed cyclically by the logic processing unit within the central control module 40, and specifically includes the following sub-steps: S401, Active pressure equalization control step for residual gas at the top of the tower: When the adsorption cycle of the first adsorption tower 11 ends, the central control module 40 obtains the pressure value of the first adsorption tower 11 through the first pressure transmitter and the second pressure transmitter, respectively. Pressure value of the second adsorption tower 12 The central control module 40 calculates the real-time pressure difference between the two towers. .

[0041] when Greater than the preset start-up differential pressure threshold At this time, the central control module 40 controls the tower top pressure equalization regulating valve 2102 to perform a variable opening action. The control logic is set as follows: in the initial stage of pressure equalization when the pressure difference is large, the valve is limited to a small opening; as the pressure difference decreases, the valve opening is gradually increased.

[0042] Specifically, the opening degree of the pressure equalization regulating valve 2102 at the top of the tower. Following an inverse proportional adjustment function or a piecewise linear function, this embodiment adopts the following control model.

[0043] ; In the formula, Indicates time, Indicates time The target opening degree of the tower top equalizing pressure regulating valve 2102. This indicates the minimum initial opening of the valve, used to ensure a small initial flow. This represents the valve opening gain coefficient. Indicates time Real-time pressure difference at the top of the tower Indicates the measuring point at the top of the tower. This represents the initial pressure difference at the moment when pressure equalization begins.

[0044] As the pressure equalization process proceeds... Gradually decrease, valve opening The flow rate is gradually increased to maintain a sufficient isostatic flow rate in the later stages of isostaticization, ensuring a relatively stable gas flow rate throughout the isostatic process and avoiding the impact of peak flow rates on the adsorbent. When the pressure drops to the cutoff threshold (e.g., 5 kPa-10 kPa), the central control module 40 controls the tower top equalization regulating valve 2102 to close.

[0045] S402, Bypass balancing control step for potential energy exchange at the bottom of the tower. During the execution of step S401, the central control module 40 controls the bottom pressure equalization control valve 2202 to be fully open. At this time, the high-pressure gas at the bottom of the first adsorption tower 11 flows directly into the bottom of the second adsorption tower 12 through the bottom pressure equalization pipe 2203, and then recovers the high-pressure gas that is not fully utilized at the bottom of the adsorption tower and in the dead space of the pipe, transferring it to the low-pressure tower to assist in pressurization, reducing the work load of the subsequent blower, and realizing the direct transfer of pressure potential energy.

[0046] During this process, the central control module 40 monitors... rate of change When detected If the pressure is less than the preset threshold for slowing down, it indicates that the pressure at the bottom of the two towers is approaching equilibrium, or that the pressure in the first adsorption tower 11 is below the preset threshold for slowing down. Reduce to the preset intermediate pressure value At that time, the central control module 40 immediately closes the pressure equalization control valve 2202 at the bottom of the tower, ending the potential energy exchange at the bottom of the tower.

[0047] S403. Natural intake and exhaust control steps based on atmospheric pressure difference: Before the adsorption tower completes pressure equalization and is connected to the power equipment, the system utilizes the pressure inside the tower and atmospheric pressure. Passive gas exchange is performed using the natural pressure difference to reduce the starting load of power equipment.

[0048] For the first adsorption tower 11, which is in the initial stage of pressure reduction, the central control module 40 determines whether the exhaust conditions are met. ( (A positive pressure differential is set for the exhaust). If this is satisfied, the central control module 40 controls the main process valve group connected to the first adsorption tower 11 to close, and outputs a signal to open the corresponding gas supply valve 2302 of the first adsorption tower 11. At this time, the high-pressure gas remaining in the tower is discharged into the atmosphere through the silencer filter assembly 2303 by its own pressure, without the need for a vacuum pump. When dropped to near At this time, close the gas supply valve 2302, and then connect the vacuum pump for deep suction.

[0049] For the second adsorption tower 12, which is in the initial stage of pressurization, the central control module 40 determines whether the air intake conditions are met. ( (A negative pressure difference is set for the intake air). If this is met, the central control module 40 controls the main process valve group connected to the second adsorption tower 12 to close, and outputs a signal to open the corresponding air supply valve 2302 of the second adsorption tower 12. At this time, outside air is naturally drawn into the tower under atmospheric pressure, which can quickly raise the pressure inside the tower from negative pressure to near atmospheric pressure. Rise to near At this time, close the air supply valve 2302, and then connect the blower to actively pressurize. When performing the above actions, the central control module 40 runs a logic interlock detection program in real time: First interlock logic: During the opening of the tower bottom equalization control valve 2202, the program forcibly locks the two gas supply valves 2302 in the closed state to prevent high-pressure gas from bypassing and leaking into the atmosphere.

[0050] The second interlock logic: During the opening of the gas supply valve 2302, the program forcibly locks the main air inlet valve and main exhaust valve of the corresponding adsorption tower and power equipment, or controls the power equipment to be in an unloaded state to prevent airflow short circuit or equipment surge.

[0051] Abnormal protection logic: When the current sensing element detects the load current... If the system continues to exceed the rated value setting time limit, the central control module 40 determines that the system is overloaded and triggers the emergency shutdown procedure, opening the gas supply valve 2302 and the tower top pressure equalization regulating valve 2102 in sequence for pressure relief protection.

[0052] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas-suspension oil-free VPSA oxygen generation system with active residual gas recovery, characterized in that, include: The oxygen generator module is equipped with a first adsorption tower (11) and a second adsorption tower (12) arranged in parallel. The first adsorption tower (11) and the second adsorption tower (12) are filled with molecular sieves. The gas power input end of the oxygen generator module is connected to an external gas power device to introduce compressed air and provide vacuum suction power. The gas path switching module is located in the gas pipeline network of the oxygen generator module and includes a tower top pressure equalization component (21), a tower bottom pressure equalization component (22) and a tower bottom gas supply component (23). It is used to control the gas flow direction, pressure balance and interaction with the external atmosphere inside the system. The buffer output module is connected to the output end of the gas path switching module. It collects the oxygen-enriched air produced by the first adsorption tower (11) or the second adsorption tower (12) through the oxygen buffer tank (3001) and stabilizes the output pressure. The central control module connects the sensors and actuators in the oxygen generator module, the gas path switching module and the buffer output module. Based on the collected real-time pressure and current parameters, it coordinates the valve opening change rate of the pressure equalization component (21) at the top of the tower, the on / off timing of the pressure equalization component (22) at the bottom of the tower, and the connection status between the gas supply component (23) at the bottom of the tower and the atmosphere, so as to achieve a smooth transition of internal pressure in the adsorption tower and recovery of residual potential energy.

2. The residual gas active recovery oil-free VPSA oxygen generation system according to claim 1, characterized in that, The tower top equalization assembly (21) includes a tower top equalization pipe (2101), a tower top equalization regulating valve (2102), and an oxygen outlet pipe (2103). The two ends of the tower top equalization pipe (2101) are respectively airtightly connected to the top outlets of the first adsorption tower (11) and the second adsorption tower (12) to form a bidirectional gas channel. The tower top equalization regulating valve (2102) is connected in series in the middle section of the tower top equalization pipe (2101), and the tower top equalization regulating valve (2102) is configured as an electric regulating valve that can receive analog control signals to continuously adjust the valve core opening. The buffer output module is connected in parallel to the top of the first adsorption tower (11) and the second adsorption tower (12) through the oxygen outlet pipe (2103) and the tower top equalization pipe (2101).

3. The residual gas active recovery oil-free VPSA oxygen generation system according to claim 1, characterized in that, The tower bottom equalization assembly (22) includes a tower bottom inlet / outlet gas pipe (2201), a tower bottom equalization control valve (2202), and a tower bottom equalization pipe (2203). The two ends of the tower bottom inlet / outlet gas pipe (2201) are respectively fixedly connected to the bottom inlet end of the first adsorption tower (11) and the bottom inlet end of the second adsorption tower (12) to form a communication structure. The two ends of the tower bottom equalization pipe (2203) are respectively connected to the side wall of the tower bottom inlet / outlet gas pipe (2201). The tower bottom equalization control valve (2202) is installed on the pipeline path of the tower bottom equalization pipe (2203) to control the direct connection and cut-off between the bottoms of the two adsorption towers. The gas supply component (23) at the bottom of the tower includes a gas supply branch pipe (2301), a gas supply valve (2302), and a noise reduction filter component (2303). One end of each of the two gas supply branch pipes (2301) is connected to the bottom of the first adsorption tower (11) and the second adsorption tower (12), respectively. The other end of each gas supply branch pipe (2301) is fixedly connected to a gas supply valve (2302), and one end of each gas supply valve (2302) is fixedly connected to a noise reduction filter component (2303).

4. The residual gas active recovery oil-free VPSA oxygen generation system according to claim 3, characterized in that, The silencer and filter assembly (2303) in the gas replenishment assembly (23) includes a resistive silencer structure and an air filter covering the air inlet end face; the effective flow cross-sectional area of ​​the silencer and filter assembly (2303) is larger than the pipe cross-sectional area of ​​the gas replenishment branch pipe (2301), and discharges the gas in the tower to the atmosphere when the gas replenishment valve (2302) is open and the pressure in the adsorption tower is higher than the atmospheric pressure, and filters the external air and draws it into the adsorption tower when the gas replenishment valve (2302) is open and the pressure in the adsorption tower is lower than the atmospheric pressure.

5. The residual gas active recovery oil-free VPSA oxygen generation system according to claim 4, characterized in that, The sensors connected to the central control module include: The first pressure transmitter is located at the top of the first adsorption tower (11) and is used to collect the instantaneous absolute pressure value inside the first adsorption tower (11). The second pressure transmitter is located at the top of the second adsorption tower (12) and is used to collect the instantaneous absolute pressure value inside the second adsorption tower (12). The environmental pressure monitoring unit is used to collect real-time atmospheric pressure data of the environment in which the equipment is located. A current sensing element is connected in series in the power supply circuit of the external gas power equipment to detect the load current signal.

6. The residual gas active recovery oil-free VPSA oxygen generation system according to claim 5, characterized in that, The central control module is configured to execute the active pressure equalization control logic for the residual gas at the top of the tower: When the adsorption cycle ends, the central control module calculates the real-time pressure difference between the first adsorption tower (11) and the second adsorption tower (12); When the real-time pressure difference is greater than the preset start-up pressure difference threshold, the central control module sends an opening command to the tower top equalizing regulating valve (2102); During the pressure equalization process, the opening of the pressure equalization regulating valve (2102) at the top of the tower is dynamically adjusted based on the real-time pressure difference data calculated in real time, so that the opening of the pressure equalization regulating valve (2102) at the top of the tower is inversely correlated with the real-time pressure difference data, thereby limiting the gas flow rate in the initial large pressure difference stage to a preset range to prevent the molecular sieve bed from pulverizing.

7. The residual gas active recovery oil-free VPSA oxygen generation system according to claim 6, characterized in that, The central control module is configured to perform valve opening adjustment based on a function model, and the target opening of the tower top equalizing pressure regulating valve (2102) is set as the sum of the preset minimum initial opening and the dynamic opening adjustment amount; The dynamic opening adjustment amount is configured to be proportional to the attenuation ratio of the current real-time pressure difference data relative to the starting pressure difference threshold, until the real-time pressure difference data drops to the cutoff threshold, controlling the tower top equalization regulating valve (2102) to close.

8. The residual gas active recovery oil-free VPSA oxygen generation system according to claim 6, characterized in that, The central control module is configured to execute the bypass balance control logic for potential energy exchange at the base of the tower: During the execution of the active pressure equalization control logic, the pressure equalization control valve (2202) at the bottom of the tower is simultaneously controlled to be fully open, so that the gas at the bottom of the high-pressure side adsorption tower bypasses the external gas power equipment and flows directly to the bottom of the low-pressure side adsorption tower. The rate of change of the real-time pressure difference is monitored in real time. When the rate of change is less than a preset slowing threshold, or when the pressure of the high-pressure side adsorption tower drops to a preset intermediate pressure value, the pressure equalization control valve (2202) at the bottom of the tower is closed.

9. The residual gas active recovery oil-free VPSA oxygen generation system according to claim 6, characterized in that, The central control module is configured to execute natural intake and exhaust control logic based on atmospheric pressure difference: For an adsorption tower in the initial stage of depressurization, determine whether its internal pressure is higher than the sum of the real-time atmospheric pressure and the set positive pressure difference of the exhaust gas; if so, control the main process valve group connected to the external gas power equipment to close or remain closed, and open the corresponding gas supply valve (2302) to use the pressure difference to discharge the gas in the tower to the atmosphere until the pressure is close to the real-time atmospheric pressure, then close the gas supply valve (2302) and switch to the vacuum suction process. For the adsorption tower in the initial stage of pressurization, determine whether its internal pressure is lower than the difference between the real-time atmospheric pressure and the set negative pressure difference for air intake; if so, control the main process valve group connected to the external gas power equipment to close or remain closed, and open the corresponding air supply valve (2302) to use the pressure difference to draw external air into the tower until the pressure is close to the real-time atmospheric pressure, then close the air supply valve (2302) and switch to the active pressurization process.

10. The residual gas active recovery oil-free VPSA oxygen generation system according to claim 9, characterized in that, The central control module is equipped with a logic interlock program, which includes: During the period when the pressure equalization control valve (2202) at the bottom of the tower is open, the gas supply valve (2302) corresponding to the first adsorption tower (11) and the second adsorption tower (12) is forcibly locked in the closed state; During the opening of any gas supply valve (2302), the main process valve group between the corresponding adsorption tower and the external gas power equipment is forcibly locked in the closed state, or the external gas power equipment is controlled to be in the unloading state.

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