Air compressor unit energy-saving cooling control method and system

Abstract

This invention discloses a control method and system for energy saving and cooling of an air compressor unit. The air compressor unit consists of multiple air compressors connected in parallel, all supplying air to a main air supply pipeline. The method includes: detecting the real-time pressure value at a system pressure detection point set on the main air supply pipeline; shutting down one currently operating air compressor; and when the real-time pressure value drops to a preset start-up pressure value, starting the shut-down air compressor and moving it to the end of the cycle sequence. This invention, by adding pressure detection to the main air supply pipeline and modifying the sequential start-up procedure of the air compressor unit, avoids frequent depressurization and no-load operation of the air compressor and prevents high-temperature aging of the air compressor unit due to prolonged operation, thereby achieving energy saving, consumption reduction, and extending the service life of the air compressor unit.

Description

Technical Field

[0001] This invention relates to the field of air compressor unit air supply technology, specifically to a control method and system for energy saving and cooling of air compressor units. Background Technology

[0002] Currently, air compressor units are widely used in industrial production for air supply, and a common practice is to operate multiple air compressors in parallel. During actual operation, when the gas load in the system pipeline decreases, the air compressor outlet pressure will rapidly rise to the preset unloading pressure threshold. At this point, the air compressor will automatically switch to unloading mode for no-load operation.

[0003] This operating mode has many technical drawbacks: First, the air compressor still consumes a lot of electricity during no-load operation, resulting in energy waste; second, the equipment operates at high temperatures for a long time under unload conditions, accelerating the aging process of electrical components and lubricating oil; third, the above factors together lead to a significant increase in operating costs and a rise in equipment failure rate, which in turn affects the stability and reliability of the system's air supply; finally, the unstable operation of the air supply system may pose serious personal safety and equipment safety hazards to the automated production line. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology. In order to achieve the above objectives, an energy-saving and cooling control method and system for air compressor units is adopted to solve the problems mentioned in the background technology.

[0005] The first proposed solution is a control method for energy saving and cooling of an air compressor unit. The air compressor unit consists of multiple air compressors connected in parallel, and at least one standby air compressor is configured to supply air according to the total actual air consumption, all of which supply air to the main air supply pipeline. The method includes the following steps: The real-time pressure value of the system pressure detection point set at the very end of the main gas supply pipeline is detected. When the real-time pressure value reaches the preset system demand pressure, the DCS control system will selectively shut down one of the currently running air compressors according to the preset cycle sequence, based on the exhaust temperature and cumulative running time. When the real-time pressure value drops to the preset start-up pressure value, the DCS control system automatically starts the shut-down air compressor and moves its position to the end in the cycle sequence.

[0006] As a further technical solution of the present invention: the specific steps for shutting down a currently running air compressor are to directly switch the air compressor from a loaded or unloaded running state to a completely stopped state, rather than switching it to an unloaded and unloaded state.

[0007] As a further technical solution of the present invention: after performing any start-up or shutdown operation of the air compressor, a preset stabilization delay is required before the DCS control system judges the real-time pressure value again.

[0008] As a further technical solution of the present invention: the step of automatically starting the shut-down air compressor further includes: The DCS control system first sends a start command to the air compressor. After the air compressor has started and is running stably under load, the DCS control system receives the air compressor's running signal and then marks it as an object that can be cyclically stopped, placing it at the end of the cycle sequence (after receiving the response feedback signal from the control cabinet and the load current after the air compressor has started).

[0009] As a further technical solution of the present invention: the preset system demand pressure is an upper limit of a pressure range set based on the rated working pressure of the air compressor unit, and the preset start-up pressure value is the lower limit of the pressure range; When the real-time pressure value reaches the upper limit of the pressure range of the cement clinker rotary kiln production line, a shutdown is triggered. When the pressure drops to the lower limit of the pressure range of 0.45MPa, a restart is triggered after a 30-second delay. After a 3-minute delay, a low pressure alarm is triggered in the system pipeline network. The fixed working pressure of the main process pipeline network of the cement clinker rotary kiln production line is 0.4MPa, with an upper limit of 0.55MPa and a lower limit of 0.4MPa.

[0010] As a further technical solution of the present invention: the preset cycle sequence is an optimized sequence generated by dynamically sorting the real-time cylinder head exhaust temperature and cumulative running time of each air compressor. The compressor with the highest cylinder head exhaust temperature is shut down first. When the cylinder head exhaust temperatures of two air compressors are the same, the air compressor with the longest cumulative running time is shut down (the cumulative running time recorded by the field control cabinet of each air compressor is received and sorted once a month).

[0011] As a further technical solution of the present invention: the DCS control system is also used for: Calculate the rate of change of the real-time pressure value and the cylinder head exhaust temperature; Based on the difference between the current pressure value and the system demand pressure, and the rate of change, predict the remaining time required to reach the system demand pressure; If the remaining time is lower than a preset threshold, the auxiliary equipment will be shut down in advance or an early warning will be issued.

[0012] As a further technical solution of the present invention: after the DCS control system issues a shutdown command, if it is detected that the air compressor fails to enter the stop state within a predetermined time of 30 seconds, or the system pressure drops abnormally, the shutdown operation is immediately cancelled, and the shutdown command is executed on the next air compressor in the cycle sequence. At the same time, the fault alarm signal of the air compressor is output. The DCS control system detects that the running signal has not been cleared within 30 seconds and outputs a fault alarm signal.

[0013] As a further technical solution of the present invention: the system pressure detection point is specifically a pressure transmitter set on the common main air supply pipeline between the air compressor unit's main air storage tank and the field air storage tank, wherein the air compressor unit's main air storage tank and the field air storage tank at the very end of the gas-using workshop are on the common main air supply pipeline.

[0014] The second solution provides a technical solution: an energy-saving and cooling control system for air compressor units, comprising: At least one pressure detection module is installed on the main gas supply pipeline; Multiple air compressors; The DCS control system is communicatively connected to the pressure detection module and the multiple air compressors, and the DCS control system is configured to perform the method as described in any one of the above statements.

[0015] Compared with the prior art, the present invention has the following technical advantages: The above-mentioned technical solution involves using multiple air compressor units connected in parallel to supply air to the main air supply pipeline. The core of this method lies in: firstly, real-time monitoring of the pressure value at a system pressure detection point set on the main air supply pipeline; secondly, when the detected real-time pressure value reaches the preset system demand pressure, the DCS control system shuts down one currently operating air compressor according to a preset cycle sequence, causing it to stop completely rather than enter an unloaded state; thirdly, when the real-time pressure value drops to the preset start-up pressure value, the DCS control system automatically starts the shut-down air compressor and moves it to the end of the cycle sequence, thereby achieving orderly rotation operation of the air compressor units and on-demand air supply.

[0016] This technology effectively solves the problems of energy waste and equipment overheating caused by unloading and idling air compressors in existing technologies. By directly shutting down the air compressors when the system pressure reaches the required pressure, instead of unloading them, the power consumption during idling is significantly reduced. Simultaneously, the use of cyclical sequential control for the start and stop of each air compressor avoids prolonged continuous operation of a single unit, effectively reducing equipment operating temperature, slowing down the aging of components and lubricating oil, and extending equipment lifespan. Furthermore, by moving the already started air compressors to the end of the cycle sequence, a balanced distribution of operating time among the air compressors is achieved, improving the overall reliability and stability of the air compressor unit, reducing the risk of equipment failure and downtime, and ensuring the air supply safety of automated production lines. Attached Figure Description

[0017] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings: Figure 1 This is a schematic diagram illustrating the steps of the control method according to an embodiment of this application; Figure 2 This is a schematic diagram of the control flow steps of an embodiment disclosed in this application; Figure 3 This is a schematic diagram of control communication according to an embodiment of the present application; Figure 4 This is a schematic diagram of the control system structure according to an embodiment of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please refer to Figure 1 and Figure 2 In this embodiment of the invention, an energy-saving and cooling control method for air compressor units is applied to an air supply system in multiple manufacturing industries, consisting of multiple air compressors connected in parallel. At least one standby air compressor is configured to supply air to the main air supply pipeline based on the total actual air consumption. The method includes the following steps: Step S1: Detect the real-time pressure value of the system pressure detection point set on the main gas supply pipeline; In this embodiment, the system pressure detection point is specifically a pressure transmitter installed on the common main air supply pipeline between the air compressor unit's main air storage tank and the field air storage tank. The field air storage tank can buffer instantaneous fluctuations in field air consumption, avoiding frequent starts of the air compressor. At the same time, the proximity of the measuring point to the air consumption end allows for early detection of air pressure change trends, enabling timely activation of the air compressor to replenish and pressurize the main air storage tank, ensuring stable system pipeline pressure. The transmitter is located on the common main air supply pipeline between the air compressor unit's main air storage tank and the field air storage tank at the very end of the air-consuming workshop.

[0020] like Figure 3 The diagram shown is a schematic of control communication. For example, a high-precision pressure transmitter can be used as a pressure detection module. This pressure transmitter will transmit the acquired real-time pressure signal to the DCS control system.

[0021] Step S2: When the real-time pressure value reaches the preset system demand pressure, the DCS control system shuts down the currently running air compressor according to the preset cycle sequence, based on the exhaust temperature and cumulative running time. In this embodiment, the specific steps for shutting down a currently running air compressor are to directly switch the air compressor from a loaded or unloaded operating state to a completely stopped state, rather than switching it to an unloaded and unloaded state.

[0022] For example, if compressors 1, 2, 3, and 4 are all running, and the cycle sequence is [1,2,3,4], then the DCS will first issue a shutdown command to compressor 1, causing it to switch directly from the loaded running state to the completely stopped state (i.e., the motor stops running), rather than unloading and running unloaded.

[0023] In this embodiment, after any air compressor starts or stops, a preset stabilization delay of 3 minutes (air compressor start-up time) is required before the DCS control system re-evaluates the real-time pressure value.

[0024] In this embodiment, the step of automatically starting the shut-down air compressor further includes: The DCS control system first sends a start command to the air compressor. After the air compressor has started and is running stably under load, the DCS control system receives the air compressor's running signal and then marks it as an object that can be cyclically stopped, placing it at the end of the cycle sequence (after receiving the response feedback signal from the control cabinet and the load current after the air compressor has started).

[0025] In this embodiment, the preset system demand pressure is the upper limit of a pressure range set based on the rated working pressure of the air compressor unit, and the preset start-up pressure value is the lower limit of the pressure range. When the real-time pressure value reaches the upper limit of the pressure range of the cement clinker rotary kiln production line, a shutdown is triggered. When the pressure drops to the lower limit of the pressure range of 0.45MPa, a restart is triggered after a 30-second delay. After a 3-minute delay, a low pressure alarm is triggered in the system pipeline network. The fixed working pressure of the main process pipeline network of the cement clinker rotary kiln production line is 0.4MPa, with an upper limit of 0.55MPa and a lower limit of 0.4MPa.

[0026] Step S3: When the real-time pressure value drops to the preset start-up pressure value, the DCS control system automatically starts the shut-down air compressor and moves its position to the end in the cycle sequence.

[0027] When air compressor No. 1 stops supplying air, the total air supply of the system decreases, and the pipeline pressure gradually decreases accordingly. The DCS control system continuously monitors the real-time pressure value and compares it with an internally preset "start-up pressure value." This "start-up pressure value" is set as the minimum operating pressure to ensure normal production downstream.

[0028] In this embodiment, the preset cycle sequence is an optimized sequence generated by dynamically sorting the real-time cylinder head exhaust temperature and cumulative running time of each air compressor. The compressor with the highest cylinder head exhaust temperature is shut down first. When the cylinder head exhaust temperatures of two air compressors are the same, the air compressor with the longest cumulative running time is shut down.

[0029] In this embodiment, the preset system demand pressure is the upper limit of a pressure range set based on the rated working pressure of the air compressor unit, and the preset start-up pressure value is the lower limit of the pressure range. When the real-time pressure value reaches the upper limit of the pressure range of the cement clinker rotary kiln production line, a shutdown is triggered. When the pressure drops to the lower limit of the pressure range of 0.45MPa, a restart is triggered after a 30-second delay. After a 3-minute delay, a low pressure alarm is triggered in the system pipeline network. The fixed working pressure of the main process pipeline network of the cement clinker rotary kiln production line is 0.4MPa, with an upper limit of 0.55MPa and a lower limit of 0.4MPa.

[0030] In this embodiment, the DCS control system is also used for: Calculate the rate of change of the real-time pressure value; Based on the difference between the current pressure value and the system demand pressure, and the rate of change, predict the remaining time required to reach the system demand pressure; If the remaining time is lower than a preset threshold, the auxiliary equipment will be shut down in advance or an early warning will be issued.

[0031] Working principle: By monitoring the system pressure in real time, the air compressors are shut down in a preset sequence when the pressure reaches the upper limit, preventing them from entering an unloaded state and thus achieving energy saving and cooling. When the pressure drops to the lower limit, the shut-down air compressors are restarted and placed at the end of the cycle sequence to ensure that the running time of each air compressor is relatively balanced.

[0032] This embodiment provides an energy-saving and cooling control system for an air compressor unit, including: like Figure 4 As shown, the diagram is a schematic diagram of the control system structure; At least one pressure detection module is installed on the main air supply pipeline; in practice, a temperature detection module is also installed on each air compressor and installed on the cylinder head exhaust pipeline.

[0033] Multiple air compressors; The DCS control system is communicatively connected to the pressure detection module and the multiple air compressors, and the DCS control system is configured to perform the method as described in any one of the above statements.

Claims

1. A control method for energy saving and cooling of an air compressor unit, wherein the air compressor unit is composed of multiple air compressors connected in parallel, and at least one standby air compressor is configured to supply air according to the total actual air consumption, all supplying air to the main air supply pipeline, characterized in that, Includes the following steps: The real-time pressure value of the system pressure detection point set at the very end of the main gas supply pipeline is detected. When the real-time pressure value reaches the preset system demand pressure, the DCS control system shuts down one of the currently running air compressors according to the preset cycle sequence. When the real-time pressure value drops to the preset start-up pressure value, the DCS control system automatically starts the shut-down air compressor and moves its position to the end in the cycle sequence.

2. The energy-saving and cooling control method for an air compressor unit according to claim 1, characterized in that, The specific steps for shutting down a currently running air compressor are to directly switch the air compressor from a loaded or unloaded operating state to a completely stopped state, rather than switching it to an unloaded and unloaded state.

3. The energy-saving and cooling control method for an air compressor unit according to claim 1, characterized in that, After any air compressor is started or stopped, a preset stabilization delay is required before the DCS control system re-evaluates the real-time pressure value.

4. The energy-saving and cooling control method for an air compressor unit according to claim 1, characterized in that, The step of automatically starting the shut-down air compressor further includes: The DCS control system first sends a start command to the air compressor. After the compressor starts up and runs stably under load, it is then marked as an object that can be cyclically stopped and placed at the end of the cycle sequence.

5. The energy-saving and cooling control method for an air compressor unit according to claim 1, characterized in that, The preset system demand pressure is the upper limit of a pressure range set based on the rated working pressure of the air compressor unit, and the preset start-up pressure value is the lower limit of this pressure range. When the real-time pressure value reaches the upper limit of the pressure range of the cement clinker rotary kiln production line, a shutdown is triggered. When the pressure drops to the lower limit of the pressure range of 0.45MPa, a restart is triggered after a 30-second delay. After a 3-minute delay, a low pressure alarm is triggered in the system pipeline network. The fixed working pressure of the main process pipeline network of the cement clinker rotary kiln production line is 0.4MPa, with an upper limit of 0.55MPa and a lower limit of 0.4MPa.

6. The energy-saving and cooling control method for an air compressor unit according to claim 1, characterized in that, The preset cycle sequence is an optimized sequence generated by dynamically sorting the real-time cylinder head exhaust temperature and cumulative running time of each air compressor. The sorting is performed once a month based on the cumulative running time recorded by each air compressor.

7. The energy-saving and cooling control method for an air compressor unit according to claim 1, characterized in that, The DCS control system is also used for: Calculate the rate of change of the real-time pressure value and the cylinder head exhaust temperature; Based on the difference between the current pressure value and the system demand pressure, and the rate of change, predict the remaining time required to reach the system demand pressure; If the remaining time is lower than a preset threshold, the auxiliary equipment will be shut down in advance or an early warning will be issued.

8. The energy-saving and cooling control method for an air compressor unit according to claim 1, characterized in that, After the DCS control system issues a shutdown command, if it detects that the air compressor fails to enter the stop state within the predetermined time of 30 seconds, or the system pressure drops abnormally, the shutdown operation is immediately canceled, and the shutdown command is executed on the next air compressor in the cycle sequence. At the same time, a fault alarm signal for the air compressor is output. The DCS control system outputs a fault alarm signal if it detects that the running signal has not been cleared within 30 seconds.

9. The energy-saving and cooling control method for an air compressor unit according to claim 1, characterized in that, The system pressure detection point is specifically a pressure transmitter installed on the common main air supply pipeline between the air compressor unit's main air storage tank and the field air storage tank.

10. An energy-saving cooling control system for an air compressor unit, characterized in that, include: At least one pressure detection module is installed on the main gas supply pipeline; Multiple air compressors; The DCS control system is communicatively connected to the pressure detection module and the multiple air compressors, and the DCS control system is configured to perform the method as described in any one of claims 1 to 9.

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