Balanced distribution control method for main control post-processing of compressed air system

Abstract

The present invention relates to gas processing technology, and aims to provide a balanced transmission and distribution control method for post-processing of a main control system supporting a compressed air system. It includes: constructing a compressed air and post-processing balanced transmission and distribution system based on the main control system; constructing a visualized initial resistance characteristic database and an interpolation fitting resistance characteristic database for the post-processing equipment of the entire system; and performing balanced transmission and distribution control of the post-processing equipment. The method proposed in the present invention to construct a visualized initial resistance characteristic based on a multi-point measurement method is not limited to the type of equipment and has stronger versatility and universality; the resistance characteristics of the equipment from the minimum flow rate to the maximum flow rate can be monitored and analyzed to realize visualization of the resistance characteristics; the operating resistance loss value can be calculated based on the measured monitoring data, and based on the difference between the resistance loss value and the initial state, an early warning can be issued as to whether the equipment needs maintenance; according to the differences in equipment models, a solution for visual control of hydraulic balance in different situations is provided.

Description

Technical Field

[0001] The present invention relates to gas processing technology, and in particular to a balanced transmission and distribution control method for main control post-processing of a compressed air system based on visualization of operating resistance characteristics. Background Art

[0002] Compressed air systems are a widely used utility. Depending on user needs, different sites may have varying quality requirements for the compressed air they provide. To meet these quality requirements, compressed air systems require a corresponding post-processing system (including but not limited to dryers, dust filters, and other equipment).

[0003] like Figure 1 As shown in Figure 2, in traditional compressed air after-treatment systems, each compressor is typically equipped with dedicated after-treatment equipment, employing a one-to-one correspondence approach. The advantage of this approach is the direct coupling between the compressor and after-treatment equipment, eliminating the need to consider hydraulic balance during operation (note: hydraulic properties are a fundamental term in fluid mechanics and are not limited to water). Under given design load conditions, after-treatment equipment typically operates in conjunction with the corresponding compressor, making it easier to manage and control from a purely equipment perspective. However, the major drawback of this approach is that if a compressor shuts down for some reason, its associated after-treatment equipment must also shut down, preventing the overall scheduling of multi-host operation. Alternatively, a problem with the after-treatment equipment could prevent the associated compressor from operating. From the perspective of overall control of a multi-host compressed air system, this strongly coupled, one-to-one correspondence inevitably carries the risk of pre-emptive resource utilization. On the other hand, optimizing transmission and distribution resistance losses, or supply pressure, for compressed air systems under different operating conditions is a key approach to reducing system energy consumption. In the traditional one-to-one coupling method, the number of post-processing equipment in operation must and can only match the number of compressors in operation, resulting in the entire system being unable to optimize and control the resistance loss of the post-processing equipment.

[0004] With the development of post-processing technology and the deepening of understanding of the optimization of pipe network resistance loss, designers have proposed a post-processing operation scheme based on the master control for the post-processing system. Figure 2As shown, the centrally managed post-processing solution establishes corresponding main pipes at the compressor outlet and dryer inlet, separating the compressor and post-processing operations into two relatively independent processes. This centrally managed system allows for decoupled control of compressor operation from that of the post-processing system. Specifically, for a given compressor unit, the control objective for its operational equipment is to maintain the required main pipe pressure. The operation of the accompanying post-processing system is thus decoupled, solely focused on ensuring that the quality parameters of the finished gas processed in the main pipe meet the required standards. The specific compressor unit or post-processing system in operation, as well as their individual operating states, can be independently controlled. This decoupling mechanism directly addresses the issue of limited operational resources and effectively ensures the safe and smooth operation of the overall system. In some on-site expansions, even filters, such as oil-injected screw compressors, are operated through centrally managed systems. From this perspective, the advantage of centrally managed systems lies in fully utilizing the invested equipment, a direct benefit. In addition, the main control provides a possibility for optimizing the operating resistance, that is, the number of post-processing equipment put into operation for the corresponding gas processing volume can be controlled. For example, the number of post-processing equipment put into operation can be more than the corresponding number of compressors. By reducing the processing flow of each post-processing equipment put into operation and connecting them in parallel through the pipeline network, the resistance loss of the post-processing link can be effectively reduced, thereby providing a feasible optimization method for the overall energy-saving operation of the compressed air system.

[0005] However, the existing post-processing systems of the main pipe system generally have a limitation, namely, hydraulic imbalance in the post-processing link. This hydraulic imbalance brings two problems: (1) Due to the difference in the hydraulic characteristics of the pipeline network, the gas volume processed by different post-processing equipment in the same post-processing system is different. Some equipment has a large corresponding processing volume due to the hydraulic characteristics of the pipeline network (for example, it is close to the main pipe, that is, the user with favorable hydraulic characteristics), which easily leads to the problem of substandard treatment quality; while some equipment has a small processing volume due to the hydraulic characteristics that are unfavorable to the user, and the equipment processing capacity cannot be fully utilized. This is a fundamental problem of the main pipe system. Therefore, compared with the traditional one-to-one corresponding solution, it is necessary to consider the configuration of a corresponding control system; but the technology of the main pipe system in this regard is still blank; (2) The post-processing equipment itself changes with the operating conditions. For example, when the same processing volume changes under different environmental conditions, or the same environmental conditions change the processing volume, or when both change, it must be adjusted within a certain range to match the changes. When these post-processing devices with certain adjustment capabilities are combined into a corresponding post-processing process, the hydraulic balance of the post-processing system must be considered again. In other words, the adjustment capability of a single device is only necessary but not sufficient for the optimal operation of the entire post-processing process.

[0006] From the above two perspectives, it can be seen that in order to ensure the quality of compressed air and the overall control post-processing link that affects the energy consumption of the compressed air system, it is necessary to build a universal balanced optimization distribution control solution for different manufacturers' products and different on-site conditions. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a balanced transmission and distribution control method for a main control post-processing of a compressed air system.

[0008] In order to solve the above technical problems, the solution adopted by the present invention is:

[0009] A method for balanced distribution control of a main control post-processing system for a compressed air system is provided, comprising the following steps:

[0010] (1) Construct a compressed air and post-processing balanced distribution system based on master control:

[0011] The system comprises: at least two compressor units operating in parallel, and at least two post-processing devices operating in parallel; the output end of each compressor unit is connected to a compressed gas main pipe; the input end of each post-processing device is connected to the compressed gas main pipe, and the output end is connected to a purified gas main pipe; the input end of the gas storage tank is connected to the purified gas main pipe, and the output end is connected to a user main pipe; the post-processing devices at least include a dryer and a dust filter connected in series; a pressure monitoring device is provided at the input end of the post-processing device, and a pressure monitoring device, a balancing regulating valve, and a flow meter are provided at the output end of the post-processing device in series.

[0012] (2) During the installation and commissioning phase, based on the initial state of the equipment, the pressure and flow data of multiple groups of different gas flow operating points are measured by utilizing the adjustment function of the balancing control valve and the pressure gauges and flow meters at both ends of the post-processing equipment. Based on the measurement results, the relationship between the actual pressure loss and the flow rate is calculated, and a visual initial resistance loss curve and a corresponding resistance characteristic array of each post-processing device are established. On this basis, a visual initial resistance characteristic database of the post-processing equipment of the entire system is constructed.

[0013] (3) On the basis of step (2), the interpolation fitting resistance characteristic curve or the segmented interpolation fitting resistance characteristic curve of each post-processing device from the minimum flow rate to the maximum flow rate is established by using the least squares method of multi-point interpolation, and on this basis, the interpolation fitting resistance characteristic database of the post-processing devices in the entire system is constructed;

[0014] (4) When all post-processing equipment comes from the same manufacturer and has the same equipment model, the balanced transmission and distribution control of the post-processing equipment shall be carried out in the following manner:

[0015] (4.1.1) Calculate the number of post-processing equipment that meets basic operating requirements using the following formula:

[0016]

[0017] In this formula, N is the number of post-processing equipment that needs to be put into operation; Q 总 is the total flow rate of the finished purified gas that needs to be processed under the current working conditions, Nm 3 / min;Q 额定 is the rated processing flow of a single post-processing device, Nm 3 / min;

[0018] (4.1.2) Calculate the gas flow rate Q that each post-processing device needs to process under balanced transmission and distribution conditions:

[0019]

[0020] (4.1.3) Taking the gas flow rate Q as the target, the balance control valve of the post-processing equipment is used to adjust the flow rate of each device to be basically consistent; then, the resistance characteristics of each post-processing device are determined by interpolation fitting the resistance characteristic database, and the resistance loss Δp of each post-processing device under the corresponding flow conditions is calculated. i Sort by

[0021] If the ranking result satisfies the following formula (1), it is determined that the resistance characteristics of each post-processing device in the system are basically the same, and the processing flow of each device can be kept consistent;

[0022]

[0023] If the resistance characteristics of a post-processing device meet the following formula (2), the device needs to be maintained first to ensure that it meets the requirements of the resistance characteristics described in formula (1);

[0024]

[0025] In the above formulas (1) and (2), Δp i is the resistance loss of a single post-processing device, and i is the given number of a single post-processing device in the system.

[0026] As a preferred solution of the present invention, on the basis of achieving flow transmission and distribution balance, the operating pressure of the system is further optimized. The specific method is: gradually reduce the operating frequency of the variable frequency screw compressor in the compressor unit, and gradually increase the opening of the balancing regulating valve at the outlet of each processing equipment while ensuring the balance of resistance loss, until the maximum opening value of a valve is greater than 80%.

[0027] As a preferred solution of the present invention, when the post-processing equipment comes from different manufacturers or from the same manufacturer but with different equipment models, step (4) is changed to the following operation to achieve balanced transmission and distribution control:

[0028] During the debugging phase after the system is installed, for a given design operating condition, the processing capacity of each post-processing device is adjusted to the rated operating condition; the pressure and flow data of each post-processing device are measured, and the resistance loss value and corresponding ratio of each device are calculated; during actual operation, even if the total flow processed by the system changes, each post-processing device distributes the flow in proportion, so that the entire system operates while basically maintaining a balanced flow transmission and distribution.

[0029] As a preferred embodiment of the present invention, the adjusted step (4) specifically includes:

[0030] (4.2.1) For a given design operating condition, adjust the processing capacity of each post-processing equipment to the rated operating condition through the balancing control valve, and calculate the corresponding resistance loss value Δp based on the monitoring data. i额定 ; As the value of the device number i changes, the initial resistance characteristic array {Δp i额定};

[0031] (4.2.2) Take one of the devices with a specified number and use its resistance loss as the static resistance characteristic value of the entire system; the ratio of the rated working condition initial resistance loss of each post-processing device to this characteristic value constitutes a ratio array {ε i}, record this array in the interpolation fitting resistance characteristic database of the entire system;

[0032] (4.2.3) When the total processing flow condition of actual operation changes, the proportional array {ε i} is used to distribute the flow to each post-processing device, so that the entire system can operate in a state of basically maintaining flow transmission and distribution balance.

[0033] As a preferred solution of the present invention, for any post-processing equipment in actual operation, the flow range it is in is determined based on the measured flow at its output end; then, the initial state resistance loss value under the corresponding flow conditions is calculated using the interpolation fitting resistance loss curve; if the minimum value of the relative deviation between the operating resistance loss value calculated based on the measured monitoring data and the initial state resistance loss value is greater than a preset threshold, a warning message is issued to prompt that the equipment needs maintenance.

[0034] As a preferred embodiment of the present invention, the initial state of the equipment in step (2) refers to a relatively ideal state when the post-processing equipment has not yet been put into operation and there is no change in equipment conditions caused by operation.

[0035] As a preferred solution of the present invention, the pressure monitoring device is a pressure gauge or a pressure sensor, the latter of which is connected to a host computer via a signal line.

[0036] As a preferred solution of the present invention, the balancing control valve is an electrically controlled pneumatic butterfly valve, or an electric butterfly valve, and is connected to a host computer via a signal line.

[0037] As a preferred solution of the present invention, a manual inspection valve is provided at each end of the balancing regulating valve, and the manual inspection valve is a gate valve or a butterfly valve.

[0038] Compared with the prior art, the technical effects of the present invention are:

[0039] 1. Compared with the existing method of constructing a resistance model, the method of constructing a visual initial resistance characteristic based on a multi-point measurement method proposed in the present invention is not limited to the type of equipment and has greater versatility and universality.

[0040] 2. Calculate the resistance characteristics based on the measured data of different post-processing equipment, and further use the least squares method of multi-point interpolation to construct a resistance characteristic curve or a segmented resistance characteristic curve; the resistance characteristics of the equipment from minimum flow to maximum flow can be monitored and analyzed to achieve resistance characteristic visualization.

[0041] 3. Based on the application of the interpolation fitting resistance characteristic database, the present invention can calculate the operating resistance loss value based on the measured monitoring data, and issue an early warning on whether the equipment needs maintenance based on the difference between the resistance loss value and the initial state.

[0042] 4. In view of the differences in post-processing equipment models, the present invention provides two solutions for visual control of hydraulic balance in different situations, and each solution can enable the entire system to operate while basically maintaining a balance in flow distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a flow chart of a one-to-one post-processing method for a compressed air system in the prior art.

[0044] Figure 2 This is a flow chart of post-processing of compressed air master control in the prior art.

[0045] Figure 3 This is a flow chart of the post-processing of the compressed air master control for balanced transmission and distribution control provided by the present invention.

[0046] 1. Inlet filter; 2. Regulating valve; 3. Compressor; 4. Dryer; 5. Dust filter; 6. Pressure gauge; 7. Gas storage tank; 8. Balancing regulating valve; 9. Flow meter; 10. Compressed gas main; 11. Purified gas main. DETAILED DESCRIPTION

[0047] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0048] In response to the problems existing in the main control and post-processing system of the compressed air system in the existing technology, the present invention first introduces the concept of balanced control, and realizes system operation monitoring and control by adding balanced control valves, pressure monitoring equipment and flow meters.

[0049] like Figure 3 As shown, the hardware modification of the system mainly includes: (1) setting corresponding pressure signal acquisition equipment on the inlet and outlet pipelines of each post-processing device (optionally, on-site pressure gauges or pressure sensors, the latter can realize remote data transmission); (2) setting a balancing regulating valve on the outlet pipeline of each post-processing device, and matching manual inspection valves (gate valves or butterfly valves) before and after it; (3) setting a finished gas flow meter on the outlet pipeline of each post-processing device. At the same time, the system is also equipped with a host computer for installing the control platform software (running the post-processing control interface) and storing corresponding data. The above links provide the basic conditions for balanced transmission and distribution control in terms of software and hardware, and constitute the difference between the present invention and the existing master control post-processing in terms of topology. Through the post-processing control interface, the present invention can realize visual analysis and control functions. At the same time, the computer in the control system is connected to the group control host for controlling each compressor group through a signal line (or the group control system is directly built into the computer) for real-time monitoring of the operation of each compressor group.

[0050] 1. Analysis of resistance characteristics of basic design of post-processing equipment

[0051] From the perspective of fluid mechanics, the traditional method of analyzing resistance characteristics is to construct a resistance model:

[0052]

[0053] in:

[0054] Δp——resistance loss, inlet and outlet pressure difference, MPa;

[0055] k(ρ, p, T) - resistance coefficient, dimensionless, with a more complex empirical formula and temperature and pressure correction model;

[0056] v——average flow velocity of the flowing medium cross section, m / s;

[0057] ρ——density of the flowing medium, kg / m 3 ;

[0058] p——working pressure, MPa;

[0059] T——operating temperature, K.

[0060] However, for a given post-processing device, varying drying mechanisms can lead to differences in resistance characteristics and resistance change characteristics during actual operation. Furthermore, due to differences in gas flow structures between different brands and types of post-processing equipment, it's difficult to develop a universally applicable model for the flow resistance coefficient. Therefore, from a fluid mechanics perspective, constructing post-processing resistance analysis using the traditional local resistance coefficient approach and flow resistance model has certain limitations, and it's also difficult to develop a universal model.

[0061] By deploying a balancing control valve on the outlet piping of post-processing equipment, the present invention proposes a method for constructing resistance characteristics based on multi-point field measurements using interpolation and fitting. For post-processing equipment, resistance curves for different throughput rates are directly constructed based on actual measured parameters, rather than considering a resistance model. The basic process of this method involves adding a balancing control valve to the existing system. Utilizing its adjustment function, in conjunction with a pressure gauge and flowmeter, the relationship between the actual pressure loss and flow rate of the equipment at multiple operating points is measured, creating an initial resistance characteristic diagram for the equipment. During the installation and commissioning phase, a visual database of initial resistance characteristics is constructed for each device number based on the equipment's initial state. This initial state refers to a relatively ideal state of the post-processing equipment, preserving conditions unaffected by operational changes, such as a dryer with no pipe corrosion or a desiccant with no adsorbent degradation. Based on this process, a corresponding resistance characteristic database can be constructed using actual test data and multi-point interpolation, rather than using conventional modeling techniques. From this perspective, the method proposed in this invention for constructing visual initial resistance characteristics based on multi-point field measurements is relatively more versatile and applicable.

[0062] For example: For a given post-processing device, its number is i, and the corresponding instrument parameter number is also numbered based on it. For example, the inlet pressure value of the device is numbered p i1 , the outlet pressure value is numbered as p i2 , the traffic number is Q i During the design process of the equipment, there will be processing conditions of maximum gas volume, minimum gas volume and intermediate gas volume, and its initial resistance characteristics have a certain range of values. Based on this, according to the adjustment capacity of the balancing valve, from maximum to minimum flow rate, there are 10 flow conditions (including the maximum and minimum flow rates, the interval is divided into 9 parts), that is, the values ​​of the inlet and outlet pressures and flows tested are: p i1j 、p i2j and Q ij , where j = 1, ..., 10. During the normal commissioning of the post-processing equipment, the target working condition of the flow distribution is set, and the balance regulating valve opening is adjusted to achieve the corresponding processing flow value Q ij Then, the corresponding p i1j and pi2j , thus the resistance loss of the post-processing equipment under this flow condition can be calculated:

[0063] Δp ij =p i1j -p i2j

[0064] When j=1,……,10 corresponds to different values, we can get the array {Δp ij , Qij}.

[0065] From a visualization perspective, these measured values ​​can be plotted into corresponding resistance loss curves, with the independent variable being Q ij , the corresponding variable is Δp ij This allows for the establishment of a visual multi-point interpolated resistance curve and corresponding resistance characteristic array for each device. Throughout the system, each device can be measured using this method, thereby constructing a visual initial resistance characteristic database for the corresponding on-site post-processing equipment.

[0066] Essentially, the goal of constructing resistance characteristics is to be able to visually determine the basic resistance state of a given device based on changes in flow. Because the parameter values ​​of each discrete operating point are measured, the least squares method of multi-point interpolation is further used on this basis to construct a resistance characteristic curve or a segmented resistance characteristic curve; for example, a cubic interpolation curve is used for fitting on each corresponding segment, so that the resistance of the flow value between the interpolation nodes is calculated within the second-order accuracy range. That is, from the perspective of the least squares method, the 10 measured operating points are divided into 1, 2 or a maximum of three intervals, and Δp=a+bQ+cQ is introduced in each interval. 2 +dQ 3 Fitting curve. The interpolation fitting polynomial coefficients a, b, c, and d vary and require adjustment depending on the set range, determined based on actual measured values. Based on this model, the resistance characteristics of the device from minimum to maximum flow can be monitored and analyzed, visualizing the resistance characteristics.

[0067] An example: For a measured flow rate, determine the flow interval it is in, and calculate the initial state resistance loss value under the corresponding flow condition based on the interpolation fitting resistance characteristic database of the interval. If the difference between the operating resistance loss value calculated based on the measured monitoring data and the initial state resistance loss value is greater than the preset threshold, a warning message can be issued through the control platform software installed on the computer, prompting that the equipment needs maintenance. For example, when designing a post-processing device, the minimum value of the relative deviation is specified. When the threshold value of 30% is used to determine whether the equipment needs maintenance, the specific value of the threshold value can be adjusted according to the actual situation.

[0068] As can be seen from the above process, the resistance characteristics visualization method proposed in this invention is not limited to any specific equipment type. The field measurement and interpolation analysis methods are applicable to various types of post-processing equipment. For compressed air systems, compressed air quality is graded during operation, and the post-processing employed for each grade is, in principle, the same. To reduce the total amount of operational maintenance, the various treatment methods can be categorized into the following two scenarios.

[0069] 2. Visual control of hydraulic balance of the master control post-processing system

[0070] For systems consisting of multiple compressors and dryers, after the main pressure and quality level are determined, the system balance of the compressed air system with the specified pressure and quality level can be divided into two major types from a system perspective. The first type is when the post-processing system manufacturers have unified models, and the second type is when the post-processing system manufacturers have inconsistent models. The goal of balancing control is to ensure that each operating equipment can fully utilize its processing capacity under variable operating conditions. For a given design operating condition, this processing capacity is measured by the gas volume processed being the same as the rated gas volume, regardless of whether the model and manufacturer are unified. However, as mentioned earlier, in actual processes, since the total gas volume processed varies and often deviates significantly from the design operating conditions, it is difficult to accurately measure the transmission and distribution balance characteristics of the post-processing system simply by flow rate.

[0071] According to the above classification, the present invention provides two solutions for visual control of hydraulic balance:

[0072] (1) The situation of unified post-processing equipment manufacturers and models

[0073] For this case, as mentioned above, the hydraulic balance characteristics corresponding to the post-processing link when operating under variable working conditions require mutual verification of the two-dimensional parameters of pressure difference and flow rate, which is also the goal of the supplementary parameter information acquisition link of the present invention.

[0074] For post-treatment equipment of the same type and design, operating within the same system hierarchy, the unified characteristic of hydraulic balance is that each device should process the same flow rate. Due to their varying locations within the pipeline network, each post-treatment device corresponds to a different inlet pressure. Based on resistance characteristics, the balance characteristic must be consistent flow rates, and the resistance losses through identically designed devices should be consistent at the same flow rate. However, in practice, traditional post-treatment solutions do not utilize balancing control valves. Under varying operating conditions, the gas throughput of the equipment is directly limited by its resistance characteristics within the given structural conditions. This often results in users with favorable hydraulic conditions processing larger volumes, while users with poorer hydraulic conditions process smaller volumes. This can create a vicious cycle in post-treatment operations. Typically, for devices based on adsorption treatment principles, the maintenance frequency and workload of high-capacity equipment are increased. Furthermore, if a balancing system cannot be established, effective resistance optimization of the overall control post-treatment system becomes difficult. For example, in a centrally managed after-treatment system, under certain operating conditions, to reduce overall operating resistance, multiple devices can be used, reducing the processing capacity of each device and thus optimizing the overall resistance. However, if balance is not achieved, this goal will be difficult to achieve. Consequently, when operating conditions change, the traditional centrally managed system struggles to adapt.

[0075] For consistent selections, if visual analysis of resistance characteristics confirms that each device's operating resistance characteristics are essentially identical, the overall requirements for each operational device are: identical process flow rates and corresponding resistance losses. These two similarities ensure a balanced post-treatment system. Of course, for any given system, the existing resistance characteristics of the corresponding post-treatment equipment should be determined first.

[0076] Based on the addition of inlet and outlet pressure gauges, outlet flow meters, and balancing control valves to the traditional system, the present invention determines the number of post-processing equipment required to meet basic operating requirements for the total processing volume under any common working condition according to the following formula:

[0077]

[0078] in:

[0079] N——represents the number of post-processing equipment that needs to be put into operation;

[0080] Q 总 ——Represents the total flow rate of finished gas that needs to be processed under the current working conditions, Nm 3 / min;

[0081] Q 额定 ——Represents the rated processing flow of a single post-processing device, Nm 3 / min;

[0082] The significance of the above formula is to reserve a certain operating margin for each dryer put into operation, thereby improving the treatment quality and reducing the treatment pressure loss.

[0083] Under this condition, the flow rate that each post-processing device needs to handle under balanced conditions can be calculated:

[0084]

[0085] Taking the flow rate as the target, first adjust the flow rate of each device to a consistent state through the regulating valve; then determine the resistance characteristics of each device respectively, and calculate the corresponding resistance loss Δp of each post-processing device under the corresponding flow rate conditions. i If the following formula (1) is satisfied, it is determined that the resistance characteristics of the existing post-processing equipment are basically the same; for the post-processing equipment that meets the following formula (2), maintenance is required first to ensure that the resistance characteristics of each device can be consistent, and then the balanced transmission and distribution control of the post-processing system can be reasonably carried out.

[0086]

[0087]

[0088] Under this condition, it is required that each branch handles the same flow rate under variable working conditions, so that the first level of transmission and distribution balance can be achieved.

[0089] For compressed air systems, based on the first-level distribution balance, in fact, the system operating pressure value should be considered, that is, the operating pressure of a given pipeline system should be optimized as much as possible. At this time, the openings θx of each balanced distribution control valve should be counted and sorted. If the corresponding first-level balance conditions are met under the system operating conditions, the maximum opening max (θ i )<80%, which means that the resistance wasted in the transmission and distribution process of the entire system is too great. At this time, the opening value of the regulating valve with the largest opening is less than 80%. The system can further reduce the operating pressure value through transmission and distribution optimization, thereby reducing the overall energy consumption of producing finished gas and improving the energy efficiency of system operation.

[0090] The second level requirement of balanced control is to minimize the system transmission and distribution resistance while maintaining balance, that is, to maximize the corresponding regulating valve opening. Of course, for a given pipeline network and equipment, this maximization is difficult to achieve simply by adjusting the valve itself. The present invention proposes to use the system's existing group control system to gradually reduce the frequency of the variable frequency screw compressor of the compressor unit, and adjust the balance regulating valve of each device while minimizing the frequency, and slowly increase the opening of each valve under the premise of balanced resistance until the maximum opening value is ≥80%. For systems without frequency conversion, it is necessary to first optimize them, and improve the adjustment ability of the compressor unit by adding a frequency converter, so as to perform the second level of balanced transmission and distribution optimization on this basis.

[0091] (2) Inconsistency between manufacturers and models of post-processing equipment

[0092] Adjusting this situation requires utilizing the static resistance distribution principle of fluid mechanics, but this must be based on visual control of the system's resistance characteristics. Initial resistance characteristic analysis during the system commissioning phase forms the foundation for subsequent balance control. For a given system, during the commissioning phase, during a design load test run, the initial resistance characteristics of each device are plotted based on the resistance test system. The resistance ratios of each device are then determined based on the resistance state of the design condition.

[0093] That is, under the design operating conditions, based on the added flowmeters and regulating valves, the initial balance of the design operating conditions is ensured, and the resistance loss of each device under the corresponding processing flow conditions is measured, and the proportional distribution of static resistance is recorded. In other words, the initial resistance value of each device is proportional. Then, if the total flow rate of compressed air processed by the system changes, the flow rate of each different type of post-processing equipment is distributed according to this ratio. This way, a basic balance state can be achieved to the greatest extent possible for systems with multiple factors.

[0094] An example: The analysis method of the initial rated resistance ratio is as follows: for a given design condition, the processing capacity of each post-operation treatment equipment is adjusted to the rated condition through the regulating valve, and the corresponding resistance loss value Δp is recorded at the same time. i额定 ; As the value of the device number i changes, an initial resistance characteristic array {Δp i额定 Take one of the devices with a specified number and use its resistance as the characteristic value of the static resistance of the entire system; the ratio of the initial resistance characteristics of the rated working condition of each post-processing device (including the specified one) to the characteristic value will form a proportional array facing the rated initial resistance, defined as {ε iThis array is recorded in the previously described system interpolation fitting resistance characteristic database. When operating conditions subsequently change, the proportion of flow rate allocated to each device under different processing flow rates will be allocated according to this value. This ensures basic balance requirements, or in other words, the flow rate processed by each operating device will not significantly affect the balanced transmission and distribution. Under this distribution condition, combined with the added flowmeters and pressure sensors, the actual resistance status of each device can also be dynamically analyzed in real time.

[0095] Specific application examples:

[0096] In actual field operations, the system typically lacks data or a database for analyzing equipment resistance characteristics under the aforementioned initial design load conditions. In other words, there is no historical data to serve as a basis. The following details the actual operations involved.

[0097] (1) Equipment modification, resistance characteristics database construction, and resistance characteristics visualization

[0098] The basic starting point of this invention is to first modify the data acquisition and control systems of the traditional system. This requires adding inlet and outlet pressure sensors, outlet flowmeters, and outlet regulating valves to each device. This addition can be performed between the inlet and outlet service valves retained in the original design of each device. This can be done unit by unit without interrupting production, with the service valves of each device in the original system closed. The flowmeters can be inline plug-in type, which can be implemented without interrupting production. Of course, this is not a problem for new systems; they can simply be reserved during the design phase.

[0099] Once the data acquisition equipment is configured, resistance characteristics testing can be performed on each device. For any given device, the initial flow rate and resistance loss are known. Regardless of the operating conditions, the device under test is adjusted to its designed flow rate using the added control valve, and the corresponding resistance loss is recorded. If the measured value and the rated design resistance loss satisfy the following equation, the overall condition of the device deviates minimally from the initial design resistance characteristics. Otherwise, maintenance is required.

[0100]

[0101] As mentioned previously, the 30% threshold can be adjusted to suit different site conditions. The resistance characteristics of each device measured at this time are recorded in a database, and a database of the operating resistance characteristics of that device is constructed using the aforementioned method. For post-processing equipment requiring maintenance, a corresponding resistance characteristics database is also constructed after timely maintenance, allowing for visual resistance characteristic analysis.

[0102] (2) Classification and balance control of post-processing system

[0103] For the existing post-processing system, according to the characteristics of the equipment, it is divided into two types: the selection and manufacturer are consistent, and the selection and manufacturer are inconsistent. Then, according to the contents mentioned in the hydraulic balance visualization control of the general control post-processing system, the corresponding visualization transmission and distribution balance work is gradually carried out.

Claims

1. A method for balanced distribution control of a main control post-processing system for a compressed air system, characterized in that: The following steps are involved: (1) Construct a compressed air and post-processing balanced distribution system based on master control: The system comprises: at least two compressor units operating in parallel, and at least two post-processing devices operating in parallel; the output end of each compressor unit is connected to the compressed gas main pipe; the input end of each post-processing device is connected to the compressed gas main pipe, and the output end is connected to the purified gas main pipe; the input end of the gas storage tank is connected to the purified gas main pipe, and the output end is connected to the user main pipe; the post-processing equipment comprises at least a dryer and a dust filter connected in series; a pressure monitoring device is provided at the input end of the post-processing device, and a pressure monitoring device, a balancing regulating valve, and a flow meter are provided at the output end of the post-processing device in series. (2) During the installation and commissioning phase, based on the initial state of the post-processing equipment, the adjustment function of the balancing control valve is utilized in conjunction with the pressure monitoring equipment and flowmeters at both ends of the post-processing equipment to measure the pressure and flow data of multiple sets of different gas flow operating points; based on the measurement results, the relationship between the actual pressure loss and the flow rate is calculated, and a visual initial resistance loss curve and a corresponding resistance characteristic array of each post-processing equipment are established. On this basis, a visual initial resistance characteristic database of the post-processing equipment of the entire system is constructed; (3) On the basis of step (2), the interpolation fitting resistance characteristic curve or the segmented interpolation fitting resistance characteristic curve of each post-processing device from the minimum flow rate to the maximum flow rate is established by using the least squares method of multi-point interpolation, and on this basis, the interpolation fitting resistance characteristic database of the post-processing devices in the entire system is constructed; (4) When all post-processing equipment are from the same manufacturer and have the same model, the balanced transmission and distribution control of the post-processing equipment shall be carried out in the following manner: (4.1.1) Calculate the number of post-processing equipment that meets basic operating requirements using the following formula: In this formula, N is the number of post-processing equipment that needs to be put into operation; Q 总 is the total flow rate of the finished purified gas that needs to be processed under the current working conditions, Nm 3 / min;Q 额定 is the rated processing flow of a single post-processing device, Nm 3 / min; (4.1.2) Calculate the gas flow rate Q that each post-processing device needs to process under balanced transmission and distribution conditions: (4.1.3) Using the gas flow rate Q as the target, use the balancing control valves provided by the post-processing equipment to adjust the flow rate of each post-processing device to be roughly consistent. Then, use the interpolation fitting resistance characteristic database to determine the resistance characteristics of each post-processing device and rank the resistance loss of each post-processing device under the corresponding flow conditions. If the ranking result satisfies the following formula (1), it is determined that the resistance characteristics of each post-processing device in the system are basically the same, and the processing flow of each post-processing device can be kept consistent; If the resistance characteristics of a post-processing device meet the following formula (2), the post-processing device needs to be maintained first to ensure that the resistance characteristics described in formula (1) are consistent; In the above formulas (1) and (2), Δp i is the resistance loss of a single post-processing device, and i is the given number of a single post-processing device in the system.

2. The method according to claim 1, characterized in that On the basis of achieving flow distribution balance, the system operating pressure is further optimized by gradually reducing the operating frequency of the variable-frequency screw compressor in the compressor unit and gradually increasing the opening of the balancing control valve at the outlet of each post-processing equipment while ensuring the balance of resistance loss, until the maximum opening value of a balancing control valve is greater than 80%.

3. The method according to claim 1, characterized in that For any post-processing equipment in actual operation, the flow range it is in is determined based on the measured flow at its output end; then, the initial state resistance loss value under the corresponding flow conditions is calculated using an interpolation fitting resistance characteristic curve or a segmented interpolation fitting resistance characteristic curve; if the minimum value of the relative deviation between the operating resistance loss value calculated based on the measured monitoring data and the initial state resistance loss value is greater than a preset threshold, a warning message is issued to prompt that the post-processing equipment needs maintenance.

4. The method according to claim 1, wherein The initial state of the post-processing equipment in step (2) refers to a relatively ideal state when the post-processing equipment has not yet been put into operation and there is no change in the post-processing equipment conditions caused by operation.

5. The method according to claim 1, wherein The pressure monitoring device is a pressure gauge or a pressure sensor, the latter of which is connected to a host computer via a signal line.

6. The method according to claim 1, characterized in that The balancing control valve is an electrically controlled pneumatic butterfly valve or an electric butterfly valve, and is connected to a host computer via a signal line.

7. The method according to claim 1, characterized in that A manual inspection valve is respectively provided at both ends of the balancing regulating valve, and the manual inspection valve is a gate valve or a butterfly valve.

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