Exhaust gas treatment system automatic control method, device, equipment and storage medium

Abstract

The application discloses a waste gas treatment system automatic control method, device, equipment and storage medium, the method comprises the steps that when the preset starting condition is met, the liquid ring compressor is started; when the liquid ring compressor is successfully started, the inlet pressure of the liquid ring compressor is controlled in the preset negative pressure interval through single loop feedback control; the real-time collected inlet pressure value is taken as a parameter, and the target flow set value corresponding to the required waste gas flow of the inlet of the liquid ring compressor is determined according to the preset control rule; the waste gas flow is controlled to the flow set value corresponding to the current negative pressure sub-interval through single loop feedback control, and the liquid ring compressor is regulated to the motor frequency corresponding to the current negative pressure sub-interval. The application can effectively control the flow of the liquid ring compressor waste gas inlet in the set value range under the condition that the liquid ring compressor consumes low energy, so that the long-period continuous stable operation of the liquid ring compressor can be effectively ensured.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology, and in particular to automatic control methods, devices, equipment and storage media for waste gas treatment systems. Background Technology

[0002] To effectively and deeply treat VOCs vapors from gasoline, styrene, and other substances transported in vehicles (and ships), a "low-temperature diesel absorption" deep purification technology has been developed. This technology utilizes a liquid ring compressor to introduce exhaust gas, which is then sent to an absorption tower for oil and gas recovery. Specifically, the exhaust gas is fed into the liquid ring compressor, compressed, and then sent to the absorption tower for oil and gas recovery. A pressure sensor is installed at the inlet of the liquid ring compressor, and the inlet pressure and reflux valve are designed for single-loop control. A simple PID control algorithm is used to maintain a stable inlet pressure for the liquid ring compressor by adjusting the opening of the reflux valve.

[0003] The inventors discovered through research that the existing liquid ring compressor dynamic control method still has at least the following drawbacks:

[0004] The amount of VOCs generated during loading (loading) is dynamic, meaning the inlet pressure of the liquid ring compressor is constantly changing. This causes the inlet pressure of the liquid ring compressor to change synchronously. When the amount of VOCs fluctuates greatly, the existing technology of adjusting the opening of the liquid ring compressor's return valve cannot keep the inlet pressure of the liquid ring compressor stable. Consequently, the liquid ring compressor will frequently stop and cannot operate continuously and stably for a long time.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to effectively ensure the long-term continuous and stable operation of a liquid ring compressor while maintaining low energy consumption.

[0007] This invention provides an automatic control method for a waste gas treatment system, comprising the following steps:

[0008] S11. When the preset start-up conditions are met, start the liquid ring compressor;

[0009] S12. After the liquid ring compressor starts successfully, the inlet pressure of the liquid ring compressor, which is collected in real time, is used as a parameter and the flow rate of the exhaust gas inlet valve is used as the controlled object. The inlet pressure of the liquid ring compressor is controlled within the preset negative pressure range through single-loop feedback control.

[0010] S13. Using the real-time collected inlet pressure value as a parameter, determine the target flow set value corresponding to the required waste gas flow at the inlet of the liquid ring compressor according to a preset control rule; the preset rule includes dividing the preset negative pressure interval into a plurality of negative pressure sub-intervals, and setting a corresponding flow set value and a corresponding motor frequency for each preset negative pressure sub-interval;

[0011] S14. Taking the waste gas flow at the inlet of the liquid ring compressor as a parameter and the return valve as the controlled object, controlling the waste gas flow to the flow set value corresponding to the current negative pressure sub-interval through single-loop feedback control, and adjusting the liquid ring compressor to the motor frequency corresponding to the current negative pressure sub-interval; the return valve is arranged on a one-way return line, which is used for returning the separated gas of the gas-liquid separation tank to the waste gas inlet.

[0012] Preferably, in the embodiment of the present invention, the preset start condition includes:

[0013] The inlet pressure value at the waste gas inlet of the liquid ring compressor is greater than a preset start threshold, and the liquid ring compressor is not in an interlock or alarm state.

[0014] Preferably, in the embodiment of the present invention, the value range of the preset start threshold includes:

[0015] 0.1-0.5kPa.

[0016] Preferably, in the embodiment of the present invention, the negative pressure interval includes -10kPa<P<0kPa; the negative pressure sub-intervals include:

[0017] -10kPa<P<-7kPa, -7kPa<P<-4kPa, and -4kPa<P<0kPa.

[0018] Preferably, the embodiment of the present invention further comprises:

[0019] After the liquid ring compressor is started successfully, when the real-time collected inlet pressure value is lower than a preset extreme value, a shutdown control instruction and / or a shutdown alarm for the liquid ring compressor is generated.

[0020] Preferably, the embodiment of the present invention further comprises:

[0021] When the liquid ring compressor fails, the start-up process of the standby liquid ring compressor is executed.

[0022] In another aspect of the present invention, an automatic control device for a waste gas treatment system is further provided, comprising:

[0023] A start control unit, configured to start the liquid ring compressor when a preset start condition is met;

[0024] a first loop control unit, configured to, after the liquid ring compressor is successfully started, take the real-time collected inlet pressure of the liquid ring compressor as a parameter and the flow rate of the waste gas inlet valve as a controlled object, and control the inlet pressure of the liquid ring compressor within a preset negative pressure interval through single-loop feedback control;

[0025] a flow rate correspondence unit, configured to take the real-time collected inlet pressure value as a parameter, and determine a target flow rate set value corresponding to the waste gas flow rate required at the inlet of the liquid ring compressor according to a preset control rule; the preset rule comprises: dividing the preset negative pressure interval into a plurality of negative pressure sub-intervals, and setting a corresponding flow rate set value and a corresponding motor frequency for each preset negative pressure sub-interval;

[0026] a second loop control unit, configured to take the waste gas flow rate at the inlet of the liquid ring compressor as a parameter and the return valve as a controlled object, control the waste gas flow rate to the flow rate set value corresponding to the current negative pressure sub-interval through single-loop feedback control, and adjust the liquid ring compressor to the motor frequency corresponding to the current negative pressure sub-interval; the return valve is arranged on a one-way return pipeline, and the one-way return pipeline is used for returning the separated gas from the gas-liquid separation tank to the waste gas inlet.

[0027] Preferably, in the embodiment of the present invention, the preset start condition comprises:

[0028] the inlet pressure value at the waste gas inlet of the liquid ring compressor is greater than a preset start threshold, and the liquid ring compressor is not in an interlock or alarm state.

[0029] Preferably, in the embodiment of the present invention, the value range of the preset start threshold comprises:

[0030] 0.1-0.5kPa.

[0031] Preferably, in the embodiment of the present invention, the negative pressure interval comprises -10kPa<P<0kPa; the negative pressure sub-intervals comprise:

[0032] -10kPa<P<-7kPa, -7kPa<P<-4kPa, and -4kPa<P<0kPa.

[0033] Preferably, in the embodiment of the present invention, the system further comprises:

[0034] a shutdown alarm unit, configured to, after the liquid ring compressor is successfully started, generate a shutdown control instruction and / or a shutdown alarm for the liquid ring compressor when the real-time collected inlet pressure value is lower than a preset extreme value.

[0035] In another aspect of the embodiment of the present invention, there is further provided an automatic control device for a waste gas treatment system, comprising:

[0036] Memory, used to store computer programs;

[0037] A processor is used to invoke and execute the computer program to implement the various steps of the automatic control method for the exhaust gas treatment system as described in any of the preceding claims.

[0038] In another aspect of the present invention, a storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the various steps of the automatic control method for the exhaust gas treatment system as described in any of the preceding claims.

[0039] The automatic control equipment of the exhaust gas treatment system includes a computer program stored on a medium. The computer program includes program instructions. When the program instructions are executed by the computer, the computer performs the methods described in the above aspects and achieves the same technical effect.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The automatic control method for exhaust gas treatment in an oil and gas recovery system provided by this invention includes pressure and flow detection at the inlet of the liquid ring compressor. It also sets a pressure range (i.e., a preset negative pressure range) for the exhaust gas at the liquid ring compressor inlet during normal operation, and further divides this preset negative pressure range into three sub-ranges (i.e., negative pressure sub-ranges), corresponding to three different flow rate settings for the exhaust gas at the liquid ring compressor inlet, and three motor frequencies for the liquid ring compressor. By forming a single loop between the flow rate of the exhaust gas at the liquid ring compressor inlet and the return valve, and by adjusting the opening of the return valve, the inlet flow rate to the liquid ring compressor is kept stable, and the liquid ring compressor is adjusted to a suitable operating frequency, thus achieving energy saving and emission reduction. This control scheme can effectively control the flow rate at the liquid ring compressor inlet within the set value range while maintaining low energy consumption, thereby effectively ensuring the long-term continuous and stable operation of the liquid ring compressor.

[0042] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0043] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a flowchart illustrating the steps of the automatic control method for the waste gas treatment system described in this invention;

[0045] Figure 2 This is a schematic diagram of the structure of the waste gas treatment system described in this invention;

[0046] Figure 3 This is a schematic diagram of the structure of the automatic control device for the waste gas treatment system described in this invention;

[0047] Figure 4 This is a schematic diagram of the automatic control equipment structure of the waste gas treatment system described in this invention. Detailed Implementation

[0048] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0049] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0050] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0051] Example 1

[0052] To effectively ensure the long-term, continuous, and stable operation of the liquid ring compressor while maintaining low energy consumption, such as... Figure 1 As shown, an automatic control method for a waste gas treatment system is provided in this embodiment of the invention, including the following steps:

[0053] S11. When the preset start-up conditions are met, start the liquid ring compressor;

[0054] refer to Figure 2 In the waste gas treatment system of the present invention, a typical process flow for bleed gas from a liquid ring compressor includes:

[0055] VOCs exhaust gas generated from tank farms, sewage ponds, gasoline loading, etc. is compressed by liquid ring compressor 10 and sent to gas-liquid separator 20, where gas-liquid separation is achieved.

[0056] Regarding the liquid component, some of the liquid contained in the exhaust gas will enter the bottom of the gas-liquid separator 20 along with the working fluid of the liquid ring compressor 10. After heat exchange in the heat exchanger 30, the working fluid will enter the motor of the liquid ring compressor 10 and then be compressed by the motor of the liquid ring compressor 10 and sent to the bottom of the gas-liquid separator 20.

[0057] Regarding the gas, part of the waste gas enters the return pipeline 40 to achieve reflux to the liquid ring compressor 10 (a return valve 401 is installed on the return pipeline 40 to regulate the waste gas flow), and the other part is sent to the absorption tower for oil and gas recovery. The gas-liquid separator 20 is connected to the liquid replenishment pipeline and the liquid discharge pipeline, and two liquid discharge pumps are installed on the liquid discharge pipeline.

[0058] Temperature detection points are set before and after heat exchanger 30, using Pt100 resistance thermometers. When the temperatures before and after the heat exchanger reach the high-high limit, the liquid ring compressor interlock will be triggered, stopping the operation of the liquid ring compressor. The high-high limit for reaching the interlock is determined by the specific process conditions.

[0059] Pressure detection is installed on the gas-liquid separator 20. When the pressure inside the tank is too high, it will trigger the interlock of the liquid ring compressor and stop the operation of the liquid ring compressor.

[0060] A liquid level detector is installed on the gas-liquid separator 20 to control the opening and closing of the replenishment valve and / or drain valve based on the liquid level inside the tank. When the liquid level in the gas-liquid separator 20 drops to the low limit, the replenishment valve opens; when the liquid level rises to the normal value, the replenishment valve closes. When the liquid level in the gas-liquid separator 20 rises to the high limit, the drain valve opens; when the liquid level drops to the normal value, the drain valve closes.

[0061] When the gas-liquid separator 20 discharges liquid, the discharge pump also needs to automatically start / stop according to the operator's selection. A delay program needs to be set to ensure that the discharge pump runs after the discharge valve opens and stops before it closes.

[0062] Combustible gas detectors and toxic gas detectors are installed near the liquid ring compressor 10. When the concentration of combustible or toxic gas in the environment reaches the high limit, an alarm signal will be issued.

[0063] The control method for the liquid ring compressor 10 in this embodiment of the invention is implemented under the following prerequisites: the automatic control program of the liquid ring compressor 10 has been activated; there are no interlocks or alarms in the liquid ring compressor 10; a certain positive pressure exists at the exhaust gas inlet of the liquid ring compressor 10; the existence of a certain positive pressure at the exhaust gas inlet of the liquid ring compressor 10 indicates that the exhaust gas has diffused to the inlet of the liquid ring compressor 10, thus meeting the starting conditions of the liquid ring compressor 10. In practical applications, a preset starting threshold can be set. By judging whether the inlet pressure value of the exhaust gas inlet of the liquid ring compressor 10 is greater than the preset starting threshold, it can be determined whether the pressure at the exhaust gas inlet of the liquid ring compressor 10 meets the standard. Preferably, the preset starting threshold can be in the range of 0.1-0.5 kPa.

[0064] S12. After the liquid ring compressor is started successfully, taking the real-time collected inlet pressure of the liquid ring compressor as a parameter and the waste gas inlet valve as the controlled object, the inlet pressure of the liquid ring compressor is controlled within the preset negative pressure interval through single-loop feedback control;

[0065] In practical applications, the next step can be executed only after the liquid ring compressor 10 is started successfully; specifically, when there is an operation status feedback of the liquid ring compressor 10, it can be proved that the liquid ring compressor 10 is started successfully.

[0066] The embodiment of the present invention improves the control mode of the liquid ring compressor 10. The inventive concept of the embodiment of the present invention includes: firstly, according to the monitoring of the inlet pressure of the liquid ring compressor 10, the opening of the waste gas inlet valve 101 is adjusted, so that the inlet pressure of the liquid ring compressor 10 can be maintained within a reasonable working interval (i.e., the preset negative pressure interval).

[0067] S13. Taking the real-time collected inlet pressure value as a parameter, determine the target flow set value corresponding to the required waste gas flow at the inlet of the liquid ring compressor according to a preset control rule; the preset rule includes: dividing the preset negative pressure interval into a plurality of negative pressure sub-intervals, and setting a corresponding flow set value and a corresponding motor frequency for each preset negative pressure sub-interval;

[0068] The preset control rule in the embodiment of the present invention includes the correspondence between the inlet pressure value of the liquid ring compressor and the target flow set value, specifically:

[0069] After the inlet pressure of the liquid ring compressor 10 is maintained within the preset negative pressure interval (for example: -10kPa<P<0kPa), the correspondence between the inlet pressure value of the liquid ring compressor 10 and the target flow set value is further set; specifically: the preset negative pressure interval is further divided into a plurality of negative pressure sub-intervals, and a corresponding flow set value is set for each preset negative pressure sub-interval, that is, when the inlet pressure value of the liquid ring compressor 10 is in a certain sub-interval, it is determined that the waste gas flow at the inlet of the liquid ring compressor 10 at this time should be at a corresponding target flow set value, which can effectively avoid abnormal shutdown of the liquid ring compressor 10; in practical applications, the reasonable interval of the inlet pressure of the liquid ring compressor 10 generally will not be lower than -10kPa, so the preset negative pressure interval can be set to -10kPa<P<0kPa; then, the negative pressure sub-intervals can be set as: -10kPa<P<-7kPa, -7kPa<P<-4kPa, and -4kPa<P<0kPa, these three sub-intervals, correspondingly according to the actual working conditions of the liquid ring compressor 10, those skilled in the art can determine the target flow set values (which can be recorded as F1, F2 and F3) corresponding to the three sub-intervals according to experimental results or experience.

[0070] In this embodiment of the invention, a correspondence between each preset negative pressure sub-range and the motor frequency is also set. Specifically, the liquid ring compressor in this embodiment of the invention includes a variable frequency motor, which can adjust the motor's operating frequency according to the different negative pressure sub-ranges so that the motor can work at an appropriate operating frequency, thereby reducing the motor's ineffective energy consumption.

[0071] S14. Using the exhaust gas flow rate at the inlet of the liquid ring compressor as a parameter and the reflux valve as the controlled object, the exhaust gas flow rate is controlled to the set flow rate corresponding to the current negative pressure sub-range through single-loop feedback control, and the liquid ring compressor is adjusted to the motor frequency corresponding to the current negative pressure sub-range; the reflux valve is located in the one-way reflux pipeline, and the one-way reflux pipeline is used to return the separated gas from the gas-liquid separator to the exhaust gas inlet.

[0072] After determining the corresponding target flow rate setting value based on the inlet pressure value of the liquid ring compressor 10, the opening degree of the return valve 401 is adjusted by the control loop (i.e., single-loop feedback control) so that the exhaust gas flow rate at the inlet of the liquid ring compressor 10 reaches the corresponding flow rate setting value.

[0073] In this embodiment of the invention, the process of maintaining the inlet pressure of the liquid ring compressor within a reasonable operating range by adjusting the exhaust gas inlet valve 101 is a coarse adjustment process. In addition, this embodiment of the invention also sets up a control circuit for the return valve 401 of the one-way return pipeline 40 to further determine the amount of return exhaust gas replenishment based on the current inlet pressure value of the liquid ring compressor 10 to fine-tune the exhaust gas flow rate at the inlet of the liquid ring compressor 10, thereby making the exhaust gas flow rate at the inlet of the liquid ring compressor 10 more stable.

[0074] To ensure production safety and avoid production accidents or losses, preferably, in this embodiment of the invention, the steps of emergency alarm and / or emergency shutdown may also be included, specifically including:

[0075] When the liquid ring compressor 10 starts successfully, if the real-time collected inlet pressure value is lower than the preset extreme value, a shutdown control command and / or shutdown alarm for the liquid ring compressor 10 will be generated.

[0076] Preferably, in this embodiment of the invention, in order to reduce production losses caused by unexpected downtime, the liquid ring compressor may also be equipped with a main and backup dual motor, so that when the motor currently operating the liquid ring compressor fails, the backup motor of the liquid ring compressor is started.

[0077] In summary, the automatic control method for the exhaust gas treatment system of an oil and gas recovery system provided in this embodiment of the invention sets pressure and flow detection at the inlet of the liquid ring compressor. It also sets a pressure range (i.e., a preset negative pressure range) for the exhaust gas at the inlet of the liquid ring compressor during normal operation, and further divides this preset negative pressure range into three sub-ranges (i.e., negative pressure sub-ranges), corresponding to three different flow rate settings for the exhaust gas at the inlet of the liquid ring compressor, and three motor frequencies of the liquid ring compressor. Thus, by forming a single loop between the flow rate of the exhaust gas at the inlet of the liquid ring compressor and the return valve, and by adjusting the opening of the return valve, the inlet flow rate into the liquid ring compressor is kept stable, and the liquid ring compressor is adjusted to a suitable operating frequency, thereby simultaneously achieving energy saving and emission reduction. The control scheme of this invention can effectively control the flow rate at the inlet of the liquid ring compressor exhaust gas within the set value range while maintaining low energy consumption, thereby effectively ensuring the long-term continuous and stable operation of the liquid ring compressor.

[0078] Example 2

[0079] Corresponding to the method embodiment, another aspect of the present invention also provides an automatic control device for a waste gas treatment system. Figure 3 This diagram illustrates the structure of an automatic control device for a waste gas treatment system provided in an embodiment of the present invention. The automatic control device for the waste gas treatment system is... Figure 1 The device corresponding to the automatic control method of the waste gas treatment system in the corresponding embodiment is implemented through a virtual device. Figure 1 In the corresponding embodiment of the automatic control method for the waste gas treatment system, each virtual module constituting the automatic control device for the waste gas treatment system can be executed by electronic devices, such as network devices, terminal devices, or servers. Specifically, the automatic control device for the waste gas treatment system in this embodiment of the invention includes:

[0080] Start control unit 01 is used to start the liquid ring compressor when the preset start conditions are met;

[0081] The first loop control unit 02 is used to control the inlet pressure of the liquid ring compressor within a preset negative pressure range by using the inlet pressure of the liquid ring compressor collected in real time as a parameter and the flow rate of the exhaust gas inlet valve as the controlled object through single-loop feedback control after the liquid ring compressor is successfully started.

[0082] The flow rate corresponding unit 03 is used to determine the target flow rate setting value corresponding to the required exhaust gas flow rate at the inlet of the liquid ring compressor according to the preset control rules, using the inlet pressure value collected in real time as a parameter; the preset rules include: dividing the preset negative pressure range into multiple negative pressure sub-ranges, and setting a corresponding flow rate setting value and a corresponding motor frequency for each preset negative pressure sub-range;

[0083] The second loop control unit 04 is used to control the exhaust gas flow rate to a set value corresponding to the current negative pressure sub-range through single-loop feedback control, using the exhaust gas flow rate at the inlet of the liquid ring compressor as a parameter and the reflux valve as the controlled object. It also adjusts the liquid ring compressor to the motor frequency corresponding to the current negative pressure sub-range. The reflux valve is located in a one-way reflux pipeline, which is used to return the separated gas from the gas-liquid separator to the exhaust gas inlet.

[0084] Preferably, in this embodiment of the invention, it further includes:

[0085] A shutdown alarm unit (not shown in the figure) is used to generate a shutdown control command and / or shutdown alarm for the liquid ring compressor when the inlet pressure value collected in real time is lower than a preset extreme value after the liquid ring compressor starts successfully.

[0086] It should be noted that the specific implementation method and technical effects of the automatic control device for the waste gas treatment system in the embodiments of the present invention can be referred to Figure 1 The corresponding automatic control methods for the waste gas treatment system will not be elaborated here.

[0087] Example 3

[0088] Corresponding to the method embodiments, this embodiment of the invention also provides an automatic control device for a waste gas treatment system, such as a terminal or a server. The server can be a standalone physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The terminal can be a smartphone, tablet, laptop, desktop computer, etc., but is not limited to these.

[0089] An example diagram of the hardware structure block diagram of the automatic control equipment for the waste gas treatment system provided in this application is shown below. Figure 4 As shown, it may include:

[0090] Processor 1, communication interface 2, memory 3, and communication bus 4;

[0091] The processor 1, communication interface 2, and memory 3 communicate with each other via communication bus 4.

[0092] Optionally, communication interface 2 can be an interface of a communication module, such as the interface of a GSM module;

[0093] Processor 1 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0094] Memory 3 may include high-speed RAM, and may also include non-volatile memory, such as at least one disk drive.

[0095] Specifically, processor 1 is used to execute the computer program stored in memory 3 to perform the following steps:

[0096] S11. When the preset start-up conditions are met, start the liquid ring compressor;

[0097] S12. After the liquid ring compressor starts successfully, the inlet pressure of the liquid ring compressor, which is collected in real time, is used as a parameter and the flow rate of the exhaust gas inlet valve is used as the controlled object. The inlet pressure of the liquid ring compressor is controlled within the preset negative pressure range through single-loop feedback control.

[0098] S13. Using the inlet pressure value collected in real time as a parameter, determine the target flow rate setting value corresponding to the required exhaust gas flow rate at the inlet of the liquid ring compressor according to the preset control rules; the preset rules include: dividing the preset negative pressure range into multiple negative pressure sub-ranges, and setting a corresponding flow rate setting value and a corresponding motor frequency for each preset negative pressure sub-range;

[0099] S14. Using the exhaust gas flow rate at the inlet of the liquid ring compressor as a parameter and the reflux valve as the controlled object, the exhaust gas flow rate is controlled to the set flow rate corresponding to the current negative pressure sub-range through single-loop feedback control, and the liquid ring compressor is adjusted to the motor frequency corresponding to the current negative pressure sub-range; the reflux valve is located in the one-way reflux pipeline, and the one-way reflux pipeline is used to return the separated gas from the gas-liquid separator to the exhaust gas inlet.

[0100] Preferably, in this embodiment of the invention, it further includes:

[0101] Once the liquid ring compressor starts successfully, when the inlet pressure value collected in real time is lower than the preset extreme value, a shutdown control command and / or shutdown alarm for the liquid ring compressor is generated.

[0102] The above-described product can execute the method provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the method. Technical details not described in detail in this embodiment can be found in the automatic control method for the waste gas treatment system provided in the embodiments of the present invention.

[0103] Example 4

[0104] In this embodiment of the invention, a storage medium is also provided, which can store a program suitable for execution by a processor, the program being used for:

[0105] S11. When the preset start-up conditions are met, start the liquid ring compressor;

[0106] S12. After the liquid ring compressor starts successfully, the inlet pressure of the liquid ring compressor, which is collected in real time, is used as a parameter and the flow rate of the exhaust gas inlet valve is used as the controlled object. The inlet pressure of the liquid ring compressor is controlled within the preset negative pressure range through single-loop feedback control.

[0107] S13. Using the inlet pressure value collected in real time as a parameter, determine the target flow rate setting value corresponding to the required exhaust gas flow rate at the inlet of the liquid ring compressor according to the preset control rules; the preset rules include: dividing the preset negative pressure range into multiple negative pressure sub-ranges, and setting a corresponding flow rate setting value and a corresponding motor frequency for each preset negative pressure sub-range;

[0108] S14. Using the exhaust gas flow rate at the inlet of the liquid ring compressor as a parameter and the reflux valve as the controlled object, the exhaust gas flow rate is controlled to the set flow rate corresponding to the current negative pressure sub-range through single-loop feedback control, and the liquid ring compressor is adjusted to the motor frequency corresponding to the current negative pressure sub-range; the reflux valve is located in the one-way reflux pipeline, and the one-way reflux pipeline is used to return the separated gas from the gas-liquid separator to the exhaust gas inlet.

[0109] Preferably, in this embodiment of the invention, it further includes:

[0110] Once the liquid ring compressor starts successfully, when the inlet pressure value collected in real time is lower than the preset extreme value, a shutdown control command and / or shutdown alarm for the liquid ring compressor is generated.

[0111] Optionally, the refined and extended functions of the program can be found in the description above.

[0112] The above-described product can execute the methods provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the methods. Technical details not described in detail in this embodiment can be found in the methods provided in other embodiments of the present invention.

[0113] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0114] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0115] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0116] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0117] It should be understood that in the embodiments of this application, the claims, various embodiments, and features can be combined with each other to solve the aforementioned technical problems.

[0118] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0119] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An automatic control method for a waste gas treatment system, applied to an oil-gas recovery system comprising a liquid ring compressor, a gas-liquid separator, a one-way return pipeline with a return valve, a waste gas inlet valve, and a heat exchanger, wherein a portion of the liquid in the waste gas enters the bottom of the gas-liquid separator along with the working fluid of the liquid ring compressor, and the working fluid enters the liquid ring compressor after heat exchange in the heat exchanger, characterized in that... Including the following steps: S11. When the preset start-up conditions are met, start the liquid ring compressor; The preset start-up conditions include: the inlet pressure of the exhaust gas inlet of the liquid ring compressor is greater than the preset start-up threshold, the preset start-up threshold is 0.1-0.5 kPa, and the liquid ring compressor is not in an interlocked or alarm state; S12. After the liquid ring compressor starts successfully, the first loop control unit uses the inlet pressure of the liquid ring compressor collected in real time as a parameter and the exhaust gas inlet valve as the controlled object to control the inlet pressure of the liquid ring compressor within the preset negative pressure range of -10kPa < P < 0kPa through single-loop feedback control, so as to achieve coarse adjustment. S13. Using the inlet pressure value collected in real time as a parameter, determine the target flow rate setting value corresponding to the required exhaust gas flow rate at the inlet of the liquid ring compressor according to the preset control rules; the preset control rules include: dividing the preset negative pressure range into multiple negative pressure sub-ranges, and setting a corresponding flow rate setting value and a corresponding motor frequency for each preset negative pressure sub-range; the negative pressure sub-ranges include: a first sub-range -10kPa < P < -7kPa, a second sub-range -7kPa < P < -4kPa, and a third sub-range -4kPa < P < 0kPa; wherein, the first sub-range corresponds to the first flow rate setting value F1 and the first motor frequency, the second sub-range corresponds to the second flow rate setting value F2 and the second motor frequency, and the third sub-range corresponds to the third flow rate setting value F3 and the third motor frequency; S14. Fine-tuning the exhaust gas flow rate at the inlet of the liquid ring compressor includes: using the exhaust gas flow rate at the inlet of the liquid ring compressor as a parameter, and the reflux valve as the controlled object, the second loop control unit controls the exhaust gas flow rate to a flow rate set value corresponding to the current negative pressure sub-range through single-loop feedback control, and adjusts the liquid ring compressor to a motor frequency corresponding to the current negative pressure sub-range; the reflux valve is located in a one-way reflux pipeline, and the one-way reflux pipeline is used to return the separated gas from the gas-liquid separator to the exhaust gas inlet.

2. The automatic control method for the waste gas treatment system according to claim 1, characterized in that, Also includes: Once the liquid ring compressor starts successfully, when the inlet pressure value collected in real time is lower than the preset extreme value, a shutdown control command and / or shutdown alarm for the liquid ring compressor is generated.

3. The automatic control method for the waste gas treatment system according to claim 1, characterized in that, Also includes: When the motor of the liquid ring compressor fails, the backup motor of the liquid ring compressor is started.

4. An automatic control device for a waste gas treatment system, used to implement the automatic control method for a waste gas treatment system as described in any one of claims 1 to 3, characterized in that, include: The start control unit is used to start the liquid ring compressor when preset start conditions are met; The first loop control unit is used to control the inlet pressure of the liquid ring compressor within a preset negative pressure range by using the inlet pressure of the liquid ring compressor collected in real time as a parameter and the flow rate of the exhaust gas inlet valve as the controlled object, through single-loop feedback control after the liquid ring compressor is successfully started. A flow correspondence unit, configured to take the real-time collected inlet pressure value as a parameter, and determine a target flow set value corresponding to the required waste gas flow at the inlet of the liquid ring compressor according to a preset control rule; the preset control rule includes dividing the preset negative pressure interval into a plurality of negative pressure sub-intervals, and setting a corresponding flow set value and a corresponding motor frequency for each preset negative pressure sub-interval; the negative pressure interval includes -10kPa<P<0kPa; the negative pressure sub-intervals include -10kPa<P<-7kPa, -7kPa<P<-4kPa, and -4kPa<P<0kPa; A second loop control unit, configured to take the waste gas flow at the inlet of the liquid ring compressor as a parameter, take the return valve as the controlled object, control the waste gas flow to the flow set value corresponding to the current negative pressure sub-interval through single-loop feedback control, and adjust the liquid ring compressor to the motor frequency corresponding to the current negative pressure sub-interval; the return valve is arranged on a one-way return pipeline, and the one-way return pipeline is used for returning the separated gas of the gas-liquid separation tank to the waste gas inlet.

5. The automatic control device for the waste gas treatment system according to claim 4, characterized in that, Further comprising: A shutdown alarm unit, configured to generate a shutdown control instruction and / or a shutdown alarm for the liquid ring compressor when the real-time collected inlet pressure value is lower than a preset extreme value after the liquid ring compressor is successfully started.

6. An automatic control device for a waste gas treatment system, characterized in that, comprising: A memory, configured to store a computer program; A processor, configured to call and execute the computer program, so as to implement the steps of the automatic control method for the waste gas treatment system according to any one of claims 1 to 3.

7. A storage medium, characterized in that, comprising a software program, wherein the software program is adapted to be executed by a processor to implement the steps of the automatic control method for the waste gas treatment system according to any one of claims 1 to 3.

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