A kind of air supply aeration control system for sewage treatment

Abstract

The present invention relates to the technical field of sewage treatment, and provides an air supply aeration control system for sewage treatment, comprising: an air supply unit, a regulating unit, and an aeration unit, wherein the three units are arranged in sequence and the aeration unit is located in an aeration tank; a control unit, which is electrically connected to the above three units respectively; wherein the regulating unit is provided with a regulating valve, and the regulating valve comprises a streamlined valve seat, a streamlined valve core, a transmission mechanism and an actuator, wherein the streamlined valve seat has a throttling section, and the streamlined valve core has a linear regulating body; the actuator drives the streamlined valve core to move along the axial direction of the streamlined valve seat through the transmission mechanism, and can change the flow area between the linear regulating body and the throttling section to achieve the regulation of the air flow. Through the linear regulating body, the streamlined valve core can linearly regulate the flow within the opening range of 0 to 100%, and the valve flow and the valve core opening change are in a linear relationship, thereby avoiding the problem of poor adjustability under large opening conditions, and achieving precise and stable regulation of the aeration volume.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to an air supply aeration control system for sewage treatment. Background Art

[0002] According to statistics, about two-thirds of the energy consumption of sewage treatment plants is generated in the aeration process. Therefore, under the premise of process stability and effluent meeting discharge standards, it is necessary to carry out precise control of aeration to reduce aeration energy consumption costs.

[0003] At present, there are many intelligent aeration control systems on the market, and the configuration generally adopts the two configuration methods of "feedforward + feedback + model" and "feedback + high-quality control hardware". The "feedforward + feedback + model" configuration method can achieve a rapid increase in the aeration volume through the adjustment of the regulating valve, but the common problem is that it is difficult to accurately and stably reduce the aeration volume. If the adjustment cycle is too long, there will not be enough response speed, which will cause the aeration volume to decrease too slowly, and the system will be in an over-aerated state for a long time, affecting the stability of the total nitrogen outlet; if the response speed is too fast, it may cause the equipment to be over-adjusted, especially it may cause the blower to surge and start and stop frequently. The "feedback + high-quality control hardware" configuration method cannot fully cope with the impact of shock loads, and its information feedback is delayed, and it cannot provide effective protection for the outlet water quality.

[0004] Traditional air control valves are generally adjusted at an opening of 10% to 30%. According to measurements, the valve will produce a pressure loss of up to 58mbar at a low opening. A corresponding flow meter needs to be configured on the control valve installation pipeline. If the straight pipe section before and after the flow meter is installed is insufficient, the flow detection accuracy will be seriously affected. In addition, after the air enters the valve through the pipeline, there will be a certain error between the actual flow of the control valve and the flow detected by the flow meter during the flow adjustment process due to factors such as detection time, distance, turbulence, and pressure loss, which seriously affects the measurement and control accuracy of the control valve flow.

[0005] In addition, in aeration control, the aerators in the front section of the aeration tank often fall off / break and sludge is stratified in the outlet area due to the failure to divide the control area.

[0006] Therefore, in order to save the power consumption of the blower, stabilize the water quality of the aeration tank effluent and improve the intelligent control level of the sewage treatment plant, it is necessary to establish a new air supply and aeration control system to stably control the dissolved oxygen concentration at the level required by the process, achieve on-demand distribution of air volume, and realize the function of energy saving and efficiency improvement. Summary of the invention

[0007] In view of the deficiencies of the prior art, the present invention provides an air supply aeration control system for sewage treatment to solve the problem that the prior control system is difficult to accurately and stably regulate aeration.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] An air supply aeration control system for sewage treatment, comprising:

[0010] An air supply unit, a regulating unit, and an aeration unit are arranged in sequence, and the aeration unit is located in an aeration tank; and

[0011] A control unit, electrically connected to the above three units respectively, for coordinating their intelligent operation;

[0012] Wherein, the regulating unit is provided with a regulating valve, which includes a streamlined valve seat, a streamlined valve core, a transmission mechanism and an actuator, the streamlined valve seat has a throttling section, and the streamlined valve core has a linear regulating body; the actuator drives the streamlined valve core to move axially along the streamlined valve seat through the transmission mechanism, and can change the flow area between the linear regulating body and the throttling section to achieve air flow regulation.

[0013] In one embodiment disclosed in the present application, the streamlined valve seat is divided into an inlet straight section, an arc-shaped contraction section, a throttling section and a conical outlet section in sequence along the medium inlet and outlet direction, the inner diameter of the arc-shaped contraction section gradually decreases, the inner diameter of the conical outlet section gradually increases, and its maximum inner diameter is equal to the inner diameter of the inlet straight section, the length of the conical outlet section is greater than the inner diameter of the inlet straight section, and each section is streamlinedly connected to form a Venturi tube structure;

[0014] The streamlined valve core comprises a push rod, a slide and a linear adjustment body which are connected in sequence, the push rod is connected to the transmission mechanism, and the cross-sectional profile of the linear adjustment body is a smooth curve;

[0015] The diameter corresponding to one end point of the smooth curve is equal to the inner diameter of the throttling section, and this point is the 0% opening position in the valve stroke, and the other end point of the smooth curve is the 100% opening position in the valve stroke;

[0016] The angle between the tangent of any point on the smooth curve and the axis of the linear regulating body increases with the increase of the valve opening, and the change of the unit relative displacement at any point on the smooth curve is proportional to the change of the flow area corresponding to the point.

[0017] In one embodiment disclosed in the present application, at least three first guide plates evenly distributed around the circumference are connected to the inner side wall of the inlet straight section;

[0018] At least three second guide plates evenly distributed around the circumference are connected to the inner side wall of the conical outlet section;

[0019] The cross sections of the first guide plate and the second guide plate are both spindle-shaped structures.

[0020] In one embodiment disclosed in the present application, the slide includes a sleeve and a support plate;

[0021] The sleeve is slidably mounted on the branch pipe of the transmission mechanism, and an end of the sleeve facing the outlet of the regulating valve is provided with an open groove for the corresponding second guide plate to pass through so as to be vertically connected to the outer side wall of the branch pipe;

[0022] The support plate is vertically connected to one end of the sleeve facing the inlet of the regulating valve, and two ends of the support plate are respectively connected to the push rod and the linear regulating body.

[0023] In one embodiment disclosed in the present application, the transmission mechanism includes a gear box integrally formed with the branch pipe and internally connected, the gear box is externally connected to a support extending to the outside of the streamlined valve seat, the gear box is internally rotatably connected to a first bevel gear, the first bevel gear is meshed with a main transmission shaft with a second bevel gear at the lower end, the main transmission shaft is sealed and rotated through the support and then connected to the actuator, and the actuator is supported outside the streamlined valve seat by a bracket;

[0024] The push rod passes through the branch pipe, and one end of the push rod facing the outlet of the regulating valve is a screw rod, which extends into the gear box and cooperates with the inner hole thread of the first bevel gear.

[0025] In one embodiment disclosed in the present application, a plurality of first permanent magnets evenly distributed around the circumference are installed in the gear box at a position corresponding to the end of the branch pipe, and a plurality of second permanent magnets evenly distributed around the circumference are installed at one end of the first bevel gear facing the inlet of the regulating valve, and the second permanent magnet is arranged opposite to the side having the same magnetic pole as the first permanent magnet;

[0026] The first bevel gear, the second bevel gear and the main transmission shaft are all made of non-magnetic stainless steel.

[0027] In one embodiment disclosed in the present application, the regulating valve further includes a detection mechanism and a displacement sensor located outside the streamlined valve seat;

[0028] The detection mechanism is used to detect the pressure difference before and after the linear adjustment body in the streamlined valve seat;

[0029] The displacement sensor is used to measure the axial displacement of the linear adjustment body.

[0030] In one embodiment disclosed in the present application, the detection mechanism includes a first pressure-taking tube, a second pressure-taking tube and a micro-differential pressure transmitter, one end of the first pressure-taking tube is connected to the inlet straight section, and the other end is connected to the micro-differential pressure transmitter, one end of the second pressure-taking tube is connected to the throttling section, and the other end is connected to the micro-differential pressure transmitter, and the micro-differential pressure transmitter is electrically connected to the control unit;

[0031] The displacement sensor is fixedly mounted on the outer side wall of the throttling section and is also electrically connected to the control unit.

[0032] In one embodiment disclosed in the present application, the control unit includes the following control method:

[0033] F1. Divide the aeration tank into 2-3 target control areas, and conduct independent load assessment and air flow independent loop control for each target control area;

[0034] F2. Predict the target dissolved oxygen value for each target control area.

[0035] In one embodiment disclosed in the present application, the prediction of the dissolved oxygen target value comprises the following steps:

[0036] S21, acquiring monitoring data of the target control area, and preprocessing the acquired monitoring data;

[0037] S22. According to the monitoring data obtained in S21, a prediction model for low dissolved oxygen in the pool based on the LSTM artificial neural network is established;

[0038] S23, collecting the current water quality data of the target control area, and randomly initializing a set of aeration operation parameter data; inputting the above water quality data and aeration operation parameter data into the low dissolved oxygen prediction model of the pool established in S22, and predicting the dissolved oxygen value of the target control area in the future;

[0039] S24. Build an activated sludge model (ASM) based on the influent and effluent water quality and the plant process flow and calculate the target dissolved oxygen threshold for the aeration tank setting;

[0040] S25, judging the dissolved oxygen value predicted by S23 according to the target dissolved oxygen threshold value set by S24 to output aeration operation parameters or optimizing the aeration operation parameters by genetic algorithm;

[0041] S26. According to the aeration operation parameters outputted from S25, the aerator in the target control area is regulated.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. The regulating valve adopts a streamlined valve seat with a micro-pressure differential Venturi tube structure. Its conical outlet section is conducive to the effective recovery of the pressure difference generated during the valve adjustment process. Therefore, the inlet and outlet pressure loss of the regulating valve is extremely small at a low opening, which can prevent the blower back pressure from being too high. Through the linear regulating body with a specific smooth curve in the cross-sectional profile, the streamlined valve core can linearly adjust the flow rate within the opening range of 0 to 100%. The valve flow rate and the valve core opening change are in a linear relationship, which avoids the problem of poor adjustability under large opening conditions. The valve has good adjustment performance and realizes precise and stable adjustment of the aeration volume.

[0044] 2. The first guide plate and the second guide plate with a spindle-shaped cross section can avoid turbulence caused by the diameter change of the streamlined valve seat and effectively reduce the pressure loss of air during flow.

[0045] 3. The repulsive force formed between the first permanent magnet and the second permanent magnet can continuously push the first bevel gear, so that the bevel gear pair between the first bevel gear and the second bevel gear fits tightly, which can eliminate the gear transmission gap and has the gap compensation function at any time, effectively improving the transmission repetitive accuracy.

[0046] 4. The regulating valve integrates the functions of air flow linear regulation and pressure difference detection. Since the streamlined valve seat has the characteristics of a Venturi tube, the detection position of its detection mechanism is the same as the valve opening adjustment position, which reduces the installation requirements of the gas distribution system equipment on the pipeline, avoids the detection error caused by distance, time, turbulence, pressure loss, etc., and completely solves the problem of error between the actual flow of the regulating valve and the flow detected by the external flow meter, thereby improving the timeliness and accuracy of flow detection.

[0047] 5. The regulating valve realizes the functions of self-detection and adjustment through the control system, ensuring that the flow detection and control is not affected by static and dynamic pressure changes, improving the accuracy of flow distribution and regulation, and the measurement and control accuracy of the system flow is better than 3%.

[0048] 6. The control system performs independent load assessment and independent air flow loop control according to each target control area, and adopts cooperative adjustment of regulating valve and blower. During operation, it timely evaluates and optimizes the DO value according to load changes, ensuring that the effluent water quality can stably meet the standards under various working conditions, avoiding excessive aeration in the process, and achieving energy saving and consumption reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0050] Figure 1 It is a structural schematic diagram of the present invention;

[0051] Figure 2 It is a structural schematic diagram of a regulating valve;

[0052] Figure 3 It is a structural schematic diagram of a streamlined valve seat;

[0053] Figure 4 for Figure 3 AA-direction cross-sectional structural diagram;

[0054] Figure 5 It is a structural schematic diagram of a streamlined valve core;

[0055] Figure 6 It is a schematic diagram of the structure of the linear regulator;

[0056] Figure 7 This is a flow characteristic diagram of a DN250 regulating valve;

[0057] Figure 8 The target dissolved oxygen calculation flow chart of the present invention;

[0058] Fig. 9 This is a schematic diagram of the dissolved oxygen curve of the aeration tank in the sewage treatment site for one month.

[0059] The following are the descriptions of the reference numerals:

[0060] a, air supply unit, a1, blower, a2, control cabinet, b, regulating unit, c, aeration unit, d, control unit;

[0061] 100, regulating valve, 110, streamlined valve seat, 111, inlet straight section, 112, arc-shaped contraction section, 113, throttling section, 114, conical outlet section, 115, first guide plate, 116, second guide plate, 120, streamlined valve core, 121, push rod, 122, slide, 122a, sleeve, 122b, support plate, 123, linear adjustment body, 124, first end cover, 130, transmission mechanism, 1 31. branch pipe, 132. gear box, 133. support, 134. first bevel gear, 135. second bevel gear, 136. main transmission shaft, 137. first permanent magnet, 138. second permanent magnet, 139. second end cover, 140. actuator, 141. bracket, 150. detection mechanism, 151. first pressure taking tube, 152. second pressure taking tube, 153. micro differential pressure transmitter, 160. displacement sensor;

[0062] 200. Pressure gauge. DETAILED DESCRIPTION

[0063] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0064] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0065] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0066] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0067] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0068] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention.

[0069] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0070] See also Figures 1 to 9 As shown, the present invention provides an air supply aeration control system for sewage treatment, comprising:

[0071] The air supply unit a, the regulating unit b, and the aeration unit c are arranged in sequence, and the aeration unit c is located in the aeration tank; and

[0072] A control unit d is electrically connected to the above three units respectively to coordinate their intelligent operation;

[0073] Among them, the regulating unit b is provided with a regulating valve 100, which includes a streamlined valve seat 110, a streamlined valve core 120, a transmission mechanism 130 and an actuator 140. The streamlined valve seat 110 has a throttling section 113, and the streamlined valve core 120 has a linear regulating body 123; the actuator 140 drives the streamlined valve core 120 to move axially along the streamlined valve seat 110 through the transmission mechanism 130, and can change the flow area between the linear regulating body 123 and the throttling section 113 to achieve air flow regulation.

[0074] See also Figure 3 As shown, the streamlined valve seat 110 is divided into an inlet straight section 111, an arc-shaped contraction section 112, a throttling section 113 and a conical outlet section 114 in sequence along the medium inlet and outlet directions. The inner diameter of the arc-shaped contraction section 112 gradually decreases, and the inner diameter of the conical outlet section 114 gradually increases, and its maximum inner diameter is equal to the inner diameter of the inlet straight section 111. The length of the conical outlet section 114 is greater than the inner diameter of the inlet straight section 111, and each section is streamlinedly connected to form a Venturi tube structure (i.e., the shape and size meet the characteristic requirements of the Venturi tube). Specifically, the diameter ratio of the throttling section 113 to the inlet straight section 111 is 0.6-0.75 to ensure that the regulating valve 100 produces a significant Venturi effect; the conical angle of the inner hole of the conical outlet section 114 is 7-8°, and the pressure difference generated during the valve adjustment process can be recovered by more than 80% in the conical outlet section 114. That is, the regulating valve 100 adopts the streamlined valve seat 110 of the micro-pressure differential venturi tube structure, and its conical outlet section 114 is conducive to the effective recovery of the pressure difference generated during the valve adjustment process. Therefore, the inlet and outlet pressure loss of the regulating valve 100 is extremely small at a low opening, which can prevent the back pressure of the blower a1 from being too high.

[0075] At least three first guide plates 115 evenly distributed around the circumference are connected to the inner side wall of the inlet straight section 111, and at least three second guide plates 116 evenly distributed around the circumference are connected to the inner side wall of the conical outlet section 114. The cross sections of the first guide plates 115 and the second guide plates 116 are both spindle-shaped. The first guide plates 115 and the second guide plates 116 with spindle-shaped cross sections can avoid turbulence caused by the diameter change of the streamlined valve seat 110, and effectively reduce the pressure loss of air during flow.

[0076] In this embodiment, the streamlined valve seat 110 is a machined part, which can effectively ensure the dimensional accuracy of the flow channel and the smooth appearance of the internal components. The material of each section is non-magnetic stainless steel, preferably a non-magnetic stainless steel casting.

[0077] See also Figure 5 and Figure 6 As shown, the streamlined valve core 120 includes a push rod 121, a slide 122 and a linear regulating body 123 which are connected in sequence. The push rod 121 is connected to the transmission mechanism 130. The cross-sectional outline X of the linear regulating body 123 is a smooth curve. The diameter corresponding to one end point (point B) of the smooth curve is equal to the inner diameter of the throttling section 113. This point is the 0 opening position in the valve stroke. The other end point (point A) of the smooth curve is the 100% opening position in the valve stroke. The angle θ between the tangent of any point on the smooth curve and the axis of the linear regulating body 123 increases with the increase of the valve opening, and the change of the unit relative displacement at any point on the smooth curve is proportional to the change of the flow area corresponding to the point. Specifically, the cross-sectional profile X of the linear regulating body 123 from A to B is closely related to the valve flow characteristics. X is a smooth curve, which can ensure the continuity of valve regulation. According to the relationship between the stroke, opening, pressure loss, flow and angle θ of the streamlined valve core 120, the change range of the angle θ from B to A is 2 to 48 degrees, which can ensure the linear relationship between the stroke of the streamlined valve core 120 and the flow change. After experimental testing, the flow characteristics of the regulating valve 100 with a specification of DN250 are as follows: Figure 7 As shown, the flow rate is linearly related to the stroke of the streamlined valve core 120 in the range of 0 to 100%. That is, the streamlined valve core 120 can linearly adjust the flow rate in the opening range of 0 to 100% through the linear adjustment body 123 whose cross-sectional profile is a specific smooth curve. The valve flow rate and the valve core opening change are linearly related, which avoids the problem of poor adjustability under large opening conditions, has good valve adjustment performance, and realizes precise and stable adjustment of aeration volume.

[0078] The slide 122 includes a sleeve 122a and a support plate 122b. The sleeve 122a is slidably mounted on the branch pipe 131 of the transmission mechanism 130. An open groove is provided at one end of the sleeve 122a facing the outlet of the regulating valve 100, for the corresponding second guide plate 116 to pass through so as to be vertically connected to the outer wall of the branch pipe 131; the support plate 122b is vertically connected to one end of the sleeve 122a facing the inlet of the regulating valve 100, and both ends of the support plate 122b are respectively connected to the push rod 121 and the linear regulating body 123.

[0079] The streamlined valve core 120 also includes a first end cover 124. After the first end cover 124 covers the push rod 121, the middle part of the first end cover 124 is fixedly connected to the end of the push rod 121 facing the inlet of the regulating valve 100 through screws, and the first end cover 124 is snap-fitted with the linear regulating body 123, and its outer surface forms a spindle shape.

[0080] See also Figure 2 and Figure 3 As shown, the transmission mechanism 130 includes a gear box 132 which is integrally formed with the branch pipe 131 and is internally connected. The gear box 132 is externally connected to a support 133 extending to the outside of the streamlined valve seat 110 (conical outlet section 114). The gear box 132 is internally rotatably connected to a first bevel gear 134. The first bevel gear 134 is meshed with a main transmission shaft 136 with a second bevel gear 135 at the lower end. The main transmission shaft 136 rotates in a sealed manner and passes through the support 133, and then is connected to the actuator 140. The actuator 140 is supported outside the streamlined valve seat 110 (conical outlet section 114) by a bracket 141. The push rod 121 passes through the branch pipe 131, and one end thereof facing the outlet of the regulating valve 100 is a screw rod, which extends into the gear box 132 and is threadedly matched with the inner hole of the first bevel gear 134. Specifically, the first bevel gear 134 is a composite bevel gear, whose inner hole is a threaded hole, the middle section is a support shaft, and the outlet end (i.e., the end facing the outlet of the regulating valve 100) is a bevel gear; the bevel gear pair transmission between the first bevel gear 134 and the second bevel gear 135 at the lower end of the main transmission shaft 136, and the thread pair transmission between the inner threaded hole of the first bevel gear 134 and the screw rod together constitute a two-stage transmission transmission mechanism 130. The actuator 140 drives the main transmission shaft 136 to rotate on the support 133, and the second bevel gear 135 drives the first bevel gear 134. The first bevel gear 134 rotates while driving the screw rod to move, so that the streamlined valve core 120 moves along the axial direction of the streamlined valve seat 110, thereby changing the opening change between the linear regulating body 123 and the throttling section 113, and then realizing the air flow regulation function. In the transmission process, because the "bevel gear pair and thread pair" transmission mode is adopted, the transmission ratio of the two is constant, and the transmission is stable and reliable.

[0081] A plurality of first permanent magnets 137 evenly distributed around the circumference are installed in the gear box 132 at the position corresponding to the end of the branch pipe 131. A plurality of second permanent magnets 138 evenly distributed around the circumference are installed at one end (i.e., the air inlet end) of the first bevel gear 134 facing the inlet of the regulating valve 100. The second permanent magnet 138 is arranged opposite to the side with the same magnetic pole as the first permanent magnet 137. The first bevel gear 134, the second bevel gear 135, and the main transmission shaft 136 are all made of non-magnetic stainless steel. Specifically, the first permanent magnet 137 and the second permanent magnet 138 are ferrite or neodymium iron boron, and the shape can be fan-shaped, rectangular or other regular shapes. When installing, it should be ensured that the two are completely installed inside and in a sealed state. When arranging, it should be ensured that their magnetic poles are consistent along the axial direction of the streamlined valve seat 110, that is, they are both S or N. However, the sides with the same magnetic poles of the two should be arranged opposite to each other and maintain a spacing of 5 to 20 mm to ensure that a repulsive magnetic force is formed between the two. Since the surrounding components are made of non-magnetic materials, the magnetic strength between the two will not be affected, thus ensuring a certain repulsive force between the two. This repulsive force continuously pushes the first bevel gear 134, making the bevel gear pair between the first bevel gear 134 and the second bevel gear 135 fit tightly, thereby eliminating the gear transmission gap and having the ability to compensate for the gap at any time, thereby effectively improving the transmission repeatability.

[0082] The gear box 132 is detachably connected to the second end cover 139, and the outer surface of the second end cover 139 is spindle-shaped after being connected to the gear box 132. The first guide plate 115, the second guide plate 116, the linear adjustment body 123, the first end cover 124, the gear box 132 and the second end cover 139 are all spindle-shaped (spindle-shaped), which effectively reduces the pressure loss of air during flow.

[0083] In this embodiment, the actuator 140 is a multi-turn electric actuator electrically connected to the control unit d. The actuator can feed back the valve state to the control unit d in real time, and receive the 4-20mA, DC analog signal or switch signal from the control unit d to adjust the valve opening, and the full stroke time is not less than 240s. Its rotation is proportional to the displacement of the streamlined valve core 120, which can effectively improve the control accuracy and sensitivity of the regulating valve 100.

[0084] The regulating valve 100 further includes a detection mechanism 150 and a displacement sensor 160 located outside the streamlined valve seat 110. The detection mechanism 150 is used to detect the pressure difference before and after the linear regulating body 123 in the streamlined valve seat 110, and the displacement sensor 160 is used to measure the axial displacement (valve position, i.e., valve opening) of the linear regulating body 123. The detection mechanism 150 includes a first pressure-taking tube 151, a second pressure-taking tube 152, and a micro-differential pressure transmitter 153. One end of the first pressure-taking tube 151 is connected to the inlet straight section 111, and the other end is connected to the micro-differential pressure transmitter 153. One end of the second pressure-taking tube 152 is connected to the throttling section 113, and the other end is connected to the micro-differential pressure transmitter 153. The micro-differential pressure transmitter 153 is electrically connected to the control unit d; the displacement sensor 160 is fixedly installed on the outer wall of the throttling section 113, and it is also electrically connected to the control unit d. Specifically, manual ball valves are provided on the first pressure-taking pipe 151 and the second pressure-taking pipe 152, and small holes are provided on the side walls of the inlet straight section 111 and the throttling section 113, respectively, for connecting the first pressure-taking pipe 151 and the second pressure-taking pipe 152. In actual operation, a pressure difference is generated in the two pressure-taking pipes due to the Venturi effect of the streamlined valve seat 110. The displacement sensor 160 is an external displacement sensor, and a magnetic sensor, a grating scale sensor, etc. can be selected according to actual needs. The control unit d is responsible for collecting and analyzing the pressure signal transmitted by the micro-differential pressure transmitter 153 and the displacement signal of the linear regulating body 123 transmitted by the displacement sensor 160. It calculates the actual flow rate of the regulating valve 100 according to the principle of the Venturi flowmeter, and reversely compensates the metering error between the set flow rate and the actual flow rate and the opening error of the flow regulation to the detection mechanism 150, thereby ensuring the timeliness of the pressure difference detection. At the same time, according to the difference between the set flow rate and the actual flow rate, it sends an adjustment signal to the actuator 140, forming a response to the command of less than 1s and a closed-loop control of the flow rate, thereby realizing the self-monitoring and rapid adjustment function of the regulating valve 100. It has been verified experimentally that the measurement and control accuracy of the flow rate of this system is better than 3%.

[0085] The regulating unit b is also provided with a pressure gauge 200 electrically connected to the control unit d. The pressure gauge 200 is fixedly installed on the connecting main pipe between the air supply unit a and the regulating unit b and is used to monitor the pressure at the inlet of the regulating valve 100.

[0086] The air supply unit a comprises a blower a1 and a control cabinet a2. At least two blowers a1 are provided in parallel and are electrically connected to the control cabinet a2 respectively. The control cabinet a2 is electrically connected to the control unit d.

[0087] The control unit d is responsible for uploading and downloading system signals, and can also obtain and record water volume, water quality data, etc. Specifically, the control unit d includes the following control methods:

[0088] F1. Divide the aeration tank into 2 to 3 target control areas, and perform independent load assessment and air flow independent loop control in each target control area.

[0089] The aeration tank is divided into 2 to 3 target control areas according to the process characteristics (such as water flow direction). The target control areas correspond to the aeration units c and the regulating valves 100. Each aeration unit c is equipped with at least three sets of aerators. According to the process requirements, the representative points are equipped with dissolved oxygen detectors. The DO, sludge concentration, and NH4 + -N, temperature and pH value are fed back to the control unit d. Each target control area performs independent load assessment and independent air flow loop control, thereby improving the aeration tank's processing capacity and impact resistance; different target control areas are responsible for different processing tasks, meeting the different aeration needs of different process areas in the aeration tank, and avoiding the aeration tank front aerator falling off / damage and the rear end area sludge stratification.

[0090] F2. Use the built-in low dissolved oxygen prediction model (LDO-LSTM) to predict the dissolved oxygen target value of each target control area.

[0091] The specific prediction steps for the dissolved oxygen target value of each target control area are as follows (see Figure 8 shown):

[0092] S21. Obtain the monitoring data of the target control area and pre-process the acquired monitoring data. The monitoring data include water quality data such as chemical oxygen demand, ammonia nitrogen, total nitrogen, total phosphorus, dissolved oxygen value, liquid level, suspended solids concentration, chemical oxygen demand, ammonia nitrogen and other water quality data of the target control area, and aeration operation parameter data such as aeration branch air flow, aeration branch air pressure, valve opening of aerobic zone air duct, blower start and stop status and blower power. The collected data is connected to PLC for real-time monitoring through modbus-tcp protocol or opcNerver, and the data pre-processing process includes outlier deletion, blank value filling and data normalization.

[0093] S22. According to the monitoring data obtained in S21, a low dissolved oxygen prediction model for the pool body based on the LSTM artificial neural network is established. The prediction step size is determined according to the specific conditions of the target control area, and the accuracy deviation of the low dissolved oxygen prediction model (LDO-LSTM) can be controlled within 5%.

[0094] S23, collecting the current water quality data of the target control area, and randomly initializing a set of aeration operation parameter data; inputting the above water quality data and aeration operation parameter data into the pool low dissolved oxygen prediction model established in S22 at the same time, and predicting the dissolved oxygen value of the future target control area.

[0095] S24. Build an activated sludge model (ASM) based on the inlet and effluent water quality and the plant process flow and calculate the target dissolved oxygen threshold for the aeration tank. The dissolved oxygen setting value at the inlet of the aeration tank is ≤2.0mg / L, and the dissolved oxygen setting value at the outlet of the aeration tank is ≤1.0mg / L.

[0096] S25. According to the target dissolved oxygen threshold value set in S24, the dissolved oxygen value predicted by S23 is judged to output the aeration operation parameters or optimize the aeration operation parameters through the genetic algorithm. If the dissolved oxygen value predicted by S23 is within the target dissolved oxygen threshold range set in S24, the current aeration operation parameters are output; if the dissolved oxygen value predicted by S23 is not within the target dissolved oxygen threshold range set in S24, the aeration operation parameters are optimized by the genetic algorithm, and the target dissolved oxygen value and judgment are calculated and judged repeatedly until the dissolved oxygen value predicted by S23 is within the target dissolved oxygen threshold range set in S24, and the current aeration operation parameters are output.

[0097] The genetic algorithm uses binary or real number coding to encode the aeration operation parameter data randomly initialized in S23, thereby generating individuals and an initial population.

[0098] The objective function is set as follows:

[0099] in is the objective function; Mathematical expression of the low dissolved oxygen prediction model for the pool constructed for S22; It is a one-dimensional array consisting of the water quality data collected in S23 and the aeration operation parameter data generated.

[0100] S26. According to the aeration operation parameters outputted from S25, the aerator in the target control area is regulated.

[0101] Through the inlet water quality, the low dissolved oxygen prediction model of the tank body based on the LSTM artificial neural network feeds forward the load change of the aeration tank, and timely and effectively matches the required air supply of the aeration tank, changing the hysteresis of relying solely on the DO value in the aeration tank for control. The aeration efficiency of the aeration tank is evaluated by the measured values ​​of ammonia nitrogen and DO at the end of the aeration tank to eliminate the differences in water temperature, air pressure, load differences of each aeration tank, and aeration efficiency. The matching target DO value is re-output according to the low dissolved oxygen prediction model to achieve the stability of dissolved oxygen in each target control area, thereby ensuring that each target control area can operate efficiently and stably.

[0102] F3. Load judgment and priority processing.

[0103] When the change in influent volume or influent load (ammonia nitrogen, COD) is judged as an impact load, the feedforward open-loop control has the highest priority; the closed-loop control of the ammonia nitrogen in the pool has the second highest priority, followed by the closed-loop control of the dissolved oxygen feedback in the pool.

[0104] F4. Coordinated regulation of blower a1 and regulating valve 100.

[0105] The regulating valve 100 of each target control zone determines the required aeration volume according to the DO setting value, dynamically adjusts the valve opening, and the execution cycle is 2 minutes. Non-step / non-PID regulation is adopted; the control unit d continuously monitors the operating status and opening of all regulating valves 100, calculates the minimum pressure required by the blower a1 to meet the required gas volume of the system, and optimizes the blower a1 according to the pressure optimization value, and adjusts the gas volume by starting and stopping the blower and the inlet and outlet guide vanes through the control cabinet a2. The control signal cycle of the blower a1 is less than or equal to 2 minutes. According to the project verification, after pressure optimization, the blower a1 can save 10% to 15% of energy consumption. Since the monitoring of the opening of the regulating valve 100 keeps most valves at the maximum opening, the pressure or aeration volume of the blower a1 can be adjusted as needed during the nitrification period to achieve the optimization adjustment of the required pressure, thereby effectively avoiding the pressure surging and frequent start and stop of the blower a1.

[0106] F5. Load assessment and optimization and adjustment of dissolved oxygen set point.

[0107] Control unit d collects NH4 at the end of the aeration tank + -N data and load assessment, set the upper limit value according to the water output requirements. + When the -N data is higher than the set upper limit, the system automatically activates the aeration ammonia nitrogen optimization control model to optimize and increase the dissolved oxygen set value; when NH4 + When the -N data is lower than the set lower limit, the system will automatically activate the aeration total nitrogen optimization control model, which automatically optimizes and adjusts the dissolved oxygen set values ​​at the front, middle and back ends of the aerobic zone of the aeration tank to prevent excessive aeration. + -N data is within the set range, and the dissolved oxygen detection value exceeds the set upper and lower limits, the dissolved oxygen optimization control model is automatically activated to optimize the target dissolved oxygen value, so that the output dissolved oxygen value can be quickly tracked and controlled.

[0108] F6. Evaluate the equipment operating status.

[0109] The control unit d monitors the pressure parameters provided by the detection mechanism 150 of each regulating valve 100 in real time, determines whether each pipeline and aerator are operating normally, and alarms and enters the safety mode when an abnormal situation occurs, to ensure the normal operation of the system.

[0110] F7. Calibration and automatic verification of flow regulation and flow detection of the control valve 100.

[0111] The above units constitute a four-stage series control structure. The first stage is a feedforward open-loop control. The optimal dissolved oxygen value is calculated by the low dissolved oxygen prediction model of the control unit d to control the total gas output of the blower a1 of the air supply unit a; the second stage is a feedback closed-loop control of ammonia nitrogen and dissolved oxygen. Through the real-time detection values ​​of ammonia nitrogen and dissolved oxygen in the aeration tank, the control unit d optimizes the target dissolved oxygen value and adjusts the opening of the regulating valve 100 of the regulating unit b; the third stage is the closed-loop control of the air supply unit a, that is, the total gas volume of the blower a1 is adjusted according to the flow signal of the regulating unit b, the opening of the regulating valve 100, and the pressure gauge 200; the fourth stage is the closed-loop control of the flow regulation and automatic verification of the flow detection of the regulating valve 100 of the regulating unit b. The use of a four-stage series control structure not only ensures a rapid response to impact loads, but also ensures that the biochemical process can stably meet the standards under the stable operation of low-carbonization.

[0112] The present invention is applicable to A / O, AAO, oxidation ditch, SBR, CASS and other processes. In this embodiment, the aeration amount required for each target control area is automatically adjusted according to the dissolved oxygen value set by the operator. Fig. 9 The figure shows the test data curve of a regulating valve position in a sewage treatment plant with AAO process for one month. In the figure, the set dissolved oxygen (DO) value can be adjusted dynamically, and the dissolved oxygen value is basically controlled within the deviation range of ±0.3mg / L. The flow curve of the regulating valve 100 in the flow range of 0-100% is consistent with the change trend of the valve position (valve opening) curve, reflecting the high regulation accuracy and fast response speed of the regulating valve 100; in addition, the blower pressure setting value at the top of the figure is basically consistent with the measured value curve, and the linearity is stable, indicating that the blower pressure regulation has a fast response speed and stable operation.

[0113] The above embodiments are only preferred embodiments of the present invention and are not limitations of the technical solutions of the present invention. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present invention.

Claims

1. An air supply aeration control system for sewage treatment, characterized in that: include: The air supply unit, the regulating unit and the aeration unit are arranged in sequence and the aeration unit is located in the aeration tank; and A control unit, electrically connected to the above three units respectively, for coordinating their intelligent operation; The air supply unit includes a blower and a control cabinet; the regulating unit is provided with a regulating valve, which includes a streamlined valve seat, a streamlined valve core, a transmission mechanism and an actuator, wherein the streamlined valve seat has a throttling section, and the streamlined valve core has a linear regulating body; the actuator drives the streamlined valve core to move along the axial direction of the streamlined valve seat through the transmission mechanism, and can change the flow area between the linear regulating body and the throttling section to achieve air flow regulation; The streamlined valve seat is divided into an inlet straight section, an arc-shaped contraction section, a throttling section and a conical outlet section in sequence along the medium inlet and outlet direction. The inner diameter of the arc-shaped contraction section gradually decreases, and the inner diameter of the conical outlet section gradually increases, and its maximum inner diameter is equal to the inner diameter of the inlet straight section. The length of the conical outlet section is greater than the inner diameter of the inlet straight section, and each section is streamlinedly connected to form a Venturi tube structure. The streamlined valve core comprises a push rod, a slide and a linear adjustment body which are connected in sequence, the push rod is connected to the transmission mechanism, and the cross-sectional profile of the linear adjustment body is a smooth curve; The diameter corresponding to one end point of the smooth curve is equal to the inner diameter of the throttling section, and this point is the 0% opening position in the valve stroke, and the other end point of the smooth curve is the 100% opening position in the valve stroke; The angle between the tangent of any point on the smooth curve and the axis of the linear regulating body increases with the increase of the valve opening, and the change of the unit relative displacement at any point on the smooth curve is proportional to the change of the flow area corresponding to the point; The transmission mechanism comprises a gear box which is integrally formed with the branch pipe of the transmission mechanism and is internally connected, the gear box is externally connected with a support extending to the outside of the streamlined valve seat, the gear box is internally rotatably connected with a first bevel gear, the first bevel gear is meshed with a main transmission shaft with a second bevel gear at the lower end, the main transmission shaft is sealed and rotated through the support and then connected to the actuator, the actuator is supported outside the streamlined valve seat by a bracket; wherein the first bevel gear is a composite bevel gear, the inner hole of which is a threaded hole, the middle section is a support shaft, and the air outlet end is a bevel gear; The push rod passes through the branch pipe, and one end of the push rod facing the outlet of the regulating valve is a screw rod, which extends into the gear box and cooperates with the inner hole thread of the first bevel gear; the bevel gear pair transmission between the first bevel gear and the second bevel gear at the lower end of the main transmission shaft, and the thread pair transmission between the inner thread hole of the first bevel gear and the screw rod together constitute the transmission mechanism of two-stage transmission; A plurality of first permanent magnets evenly distributed around the circumference are installed in the gear box at a position corresponding to the end of the branch pipe, and a plurality of second permanent magnets evenly distributed around the circumference are installed at one end of the first bevel gear facing the inlet of the regulating valve, and the second permanent magnets are arranged opposite to the side having the same magnetic pole as the first permanent magnet; The first bevel gear, the second bevel gear and the main transmission shaft are all made of non-magnetic stainless steel; The regulating valve further comprises a detection mechanism and a displacement sensor located outside the streamlined valve seat; The detection mechanism is used to detect the pressure difference before and after the linear adjustment body in the streamlined valve seat; The displacement sensor is used to measure the axis displacement of the linear adjustment body; The detection mechanism includes a first pressure-taking tube, a second pressure-taking tube and a micro-differential pressure transmitter, wherein one end of the first pressure-taking tube is connected to the inlet straight section, and the other end is connected to the micro-differential pressure transmitter, one end of the second pressure-taking tube is connected to the throttling section, and the other end is connected to the micro-differential pressure transmitter, and the micro-differential pressure transmitter is electrically connected to the control unit; The displacement sensor is fixedly mounted on the outer side wall of the throttling section and is also electrically connected to the control unit; The control unit is responsible for collecting and analyzing the pressure signal transmitted by the micro-differential pressure transmitter and the displacement signal of the linear regulating body transmitted by the displacement sensor, and calculating the current actual flow of the regulating valve according to the principle of the Venturi flowmeter, and reversely compensating the metering error between the set flow and the actual flow and the opening error of the flow regulation to the detection mechanism; at the same time, according to the difference between the set flow and the actual flow, an adjustment signal is sent to the actuator to form a response to the instruction of less than 1s and a closed-loop control of the flow; The control unit includes the following control method: F1. Divide the aeration tank into 2-3 target control areas, and conduct independent load assessment and air flow independent loop control for each target control area; F2. Predict the target dissolved oxygen value of each target control area; F3. Load judgment and priority level processing: When the water inflow or water inflow load change is judged as an impact load, the feedforward open-loop control has the highest priority; the closed-loop control of ammonia nitrogen in the pool has the second highest priority, followed by the closed-loop control of dissolved oxygen feedback in the pool; F4, collaborative regulation of the blower and the regulating valve: the regulating valve of each target control area determines the required aeration volume according to the dissolved oxygen set value, dynamically adjusts the valve opening, and the execution cycle is 2 minutes, using non-equal-step / non-PID regulation; the control unit continuously monitors the operating status and opening of all the regulating valves, calculates the minimum pressure required by the blower to meet the required gas volume of the system, and optimizes it. The blower starts and stops the blower and adjusts the gas volume through the control cabinet based on the pressure optimization value and the inlet and outlet guide vanes. The control signal cycle of the blower a1 is less than or equal to 2 minutes; F5. Load assessment and optimization of dissolved oxygen setting value: The control unit collects NH4 + -N data and load assessment, set the upper limit value according to the water output requirements; when the NH4 + -N data is higher than the set upper limit, the system automatically activates the aeration ammonia nitrogen optimization control model to optimize and increase the dissolved oxygen set value; when the NH4 + -N data is lower than the set lower limit, the system will automatically activate the aeration total nitrogen optimization control model, which automatically optimizes and adjusts the dissolved oxygen set values ​​at the front, middle and back ends of the aerobic zone of the aeration tank to prevent over-aeration; when the NH4 + -N data is within the set range, and the dissolved oxygen detection value exceeds the set upper and lower limits, the dissolved oxygen optimization control model is automatically activated to optimize the target dissolved oxygen value, so that the output dissolved oxygen value can be quickly tracked and controlled; F6. Evaluate the equipment operating status; F7. Calibration and automatic verification of the flow regulation and flow detection of the regulating valve.

2. The air supply aeration control system for sewage treatment according to claim 1, characterized in that: At least three first guide plates evenly distributed around the circumference are connected to the inner side wall of the inlet straight section; At least three second guide plates evenly distributed around the circumference are connected to the inner side wall of the conical outlet section; The cross sections of the first guide plate and the second guide plate are both spindle-shaped structures.

3. The air supply aeration control system for sewage treatment according to claim 2, characterized in that: The slide includes a sleeve and a support plate; The sleeve is slidably mounted on the branch pipe of the transmission mechanism, and an end of the sleeve facing the outlet of the regulating valve is provided with an open groove for the corresponding second guide plate to pass through so as to be vertically connected to the outer side wall of the branch pipe; The support plate is vertically connected to one end of the sleeve facing the inlet of the regulating valve, and two ends of the support plate are respectively connected to the push rod and the linear regulating body.

4. The air supply aeration control system for sewage treatment according to claim 1, characterized in that: The prediction of the dissolved oxygen target value comprises the following steps: S21, acquiring monitoring data of the target control area, and preprocessing the acquired monitoring data; S22. According to the monitoring data obtained in S21, a prediction model for low dissolved oxygen in the pool based on the LSTM artificial neural network is established; S23, collecting the current water quality data of the target control area, and randomly initializing a set of aeration operation parameter data; inputting the above water quality data and aeration operation parameter data into the low dissolved oxygen prediction model of the pool established in S22, and predicting the dissolved oxygen value of the target control area in the future; S24. Build an activated sludge model ASM based on the influent and effluent water quality and the plant process flow and calculate the target dissolved oxygen threshold for the aeration tank; S25, judging the dissolved oxygen value predicted by S23 according to the target dissolved oxygen threshold value set by S24 to output aeration operation parameters or optimizing the aeration operation parameters by genetic algorithm; S26. According to the aeration operation parameters outputted from S25, the aerator in the target control area is regulated.

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