CN110541812B

CN110541812B - Energy-saving air compressor control system and method based on DCS comprehensive control

Info

Publication number: CN110541812B
Application number: CN201910925344.6A
Authority: CN
Inventors: 沈志刚; 许江淮; 沈娅芳; 许积庄; 黄见勋; 王大伟; 林金标
Original assignee: Xiamen Huaxia International Power Development Co ltd
Current assignee: SDIC Xinjiang Lop Nur potash Co., Ltd; XIAMEN HUAXIA INTERNATIONAL POWER DEVELOPMENT Co.,Ltd.
Priority date: 2019-09-27
Filing date: 2019-09-27
Publication date: 2020-10-16
Anticipated expiration: 2039-09-27
Also published as: CN110541812A

Abstract

The invention provides an energy-saving air compressor control system and method based on DCS (distributed control system) overall control, wherein the energy-saving air compressor control system based on DCS overall control comprises a compressor unit, an electrical unit and a DCS control unit; the DCS control unit comprises a signal collector group and a DCS controller; the signal collector group is used for monitoring the running states of the electrical unit and the compressor group; and the electric unit controls the compressor unit to start, load, unload or stop according to the instruction sent by the DCS control unit. According to the energy-saving air compressor control system based on DCS comprehensive control, the DCS controller is adopted to control the compressor unit in real time, so that the operation of the compressor unit is more reasonable, and the operation energy consumption of the compressor unit can be reduced; meanwhile, data obtained by scanning of the DCS controller can be stored in a DCS historical database, so that the historical working condition of the equipment in any period of the whole life cycle can be read back, and the requirements of fault analysis and equipment optimization are fully met.

Description

Energy-saving air compressor control system and method based on DCS comprehensive control

Technical Field

The invention relates to the field of air compressor control, in particular to an energy-saving air compressor control system and method based on DCS (distributed control system) overall control.

Background

In recent years, the popularization of energy-saving products is continuously increased in China, and the development of energy-saving technology of the air compressor as a product applied to multiple industrial fields such as domestic mines, metallurgy, electric power, electronics, mechanical manufacturing, medicines, foods, textile light industry, petrochemical industry and the like has great significance to the energy-saving industry of China.

The existing active air compressor in the industrial field mainly has the following main problems. Firstly, most air compressors are originally designed and still based on a single chip microcomputer or early PLC, and a control strategy cannot be modified after being packaged and latched; secondly, the process control is simple, the adjustment precision of working condition parameters is poor, most pressure adjustment control modes are still rough mechanical pneumatic adjustment systems, the optimal point of the output adjustment of the compressor is only in the middle output section of the standard design, the linear area is narrow, the unbalance can be adjusted once the load change of a user is large, and the energy-saving efficiency is extremely low; thirdly, working condition parameters of the air compressor cannot be recalled, even the latest product can only inquire customized fault alarms within limited times, full working condition information when a fault occurs cannot be reproduced, and fault analysis cannot be effectively supported; and fourthly, the air compressor is limited by the control of a low-end single chip microcomputer and a PLC (programmable logic controller) packaged by an original factory, even if a majority of industrial enterprise main production service systems adopt an advanced industrial DCS (distributed control system) and can accept various data communication protocols such as Modbus, RS-232, RS-485 and the like, the air compressor has no data communication protocol interface, cannot exchange data with an external system, cannot improve the control precision by utilizing the superior performance of the advanced industrial control system, and becomes an information isolated island and a control short board.

Under the combined action of the social background and the current technical situation, most industrial enterprises are seriously worried about energy-saving modification projects of the air compressor, and although the working condition of the main engine of the air compressor is still good, a whole set of meat cutting modification mode for replacing new meat is finally adopted to solve the urgent need of energy saving. In the current sales market, the volume flow is more than or equal to 30m³The/min common air compressor needs about 30-50 ten thousand yuan, 3 or more air compressor stations are generally arranged in combination with industrial enterprises to form a set of air compressor station design mode, the labor material cost is superposed, one-time thorough energy-saving reconstruction of the air compressor station needs about 150 ten thousand yuan, and the recovery period of the generated energy-saving benefit is usually more than 10 years.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides the energy-saving air compressor control system and method based on DCS comprehensive control, which can be used for modifying the existing air compressor system at low cost, is particularly suitable for the situation of the existing industrial DCS control system of an industrial enterprise and achieves good energy-saving benefit.

In order to achieve the aim, the invention provides an energy-saving air compressor control system based on DCS comprehensive control, which comprises a compressor unit, an electrical unit, a signal collector group and a DCS control unit; the signal collector group is used for monitoring the running states of the electrical unit and the compressor unit; the DCS control unit sends out different control instructions according to the information fed back by the signal collector group; and the electrical unit controls the compressor unit to start, load, unload or stop according to the instruction sent by the DCS control unit.

Further, the compressor unit comprises an air filter, an electric regulating valve, a pneumatic valve, a compressor, an oil-gas barrel separator, an oil filter, a cooler and an outlet screwing valve; the air filter, the electric regulating valve, the pneumatic valve, the compressor, the oil-gas barrel separator cooler, the outlet screwing valve and the compressed gas main pipe are sequentially connected to form a compressed gas circuit; the top of the oil-gas barrel separator is connected to the front of the pneumatic valve through a discharge solenoid valve to form a discharge gas path; and an outlet pipe of the oil-gas barrel separator is connected to a driving cylinder of the pneumatic valve through a loading electromagnetic valve to form a loading gas circuit.

Further, the electric unit comprises a power supply end, an emergency stop button, a main motor contactor, a main motor star-shaped contactor and a main motor triangular contactor, wherein the main motor contactor, the main motor star-shaped contactor and the main motor triangular contactor are used for controlling power supply of the compressor motor, a cooling fan contactor is used for controlling power supply of the cooling fan motor, and the three electric branches are respectively used for controlling power supply of the electric regulating valve, the release electromagnetic valve and the loading electromagnetic valve.

Further, the signal acquisition device group includes, but is not limited to, an air-filter differential pressure switch PS₁A main motor temperature switch TS, a main motor current transducer I, a thermocouple relay TH, a phase sequence protector PH, an oil filtration pressure difference switch PS₂Separator pressure transmitter P₃Separator temperature sensor T₂Exhaust port temperature sensor T₁Exhaust port pressure transmitter P₁Closed water pressure transmitter P₄Pressure transmitter P of compressed gas main pipe₂Position feedback V of electric regulating valve_ZMain power supplyFeedback contact C of mechanical contactor_MFeedback contact C of star-type contactor of main motor_SFeedback contact C of triangular contactor of main motor_DCooling fan contactor feedback contact C_FAnd scram button feedback contact C_E。

Further, the DCS unit comprises a DCS controller, an input module, an output module and a human-computer interface; the human-computer interface comprises but is not limited to a starting control signal input interface, a stopping control signal input interface, an electric control valve control instruction input interface and a display interface.

The invention also provides an energy-saving air compressor control method based on DCS overall control, which is applied to any one of the energy-saving air compressor control systems based on DCS overall control; the method comprises the following steps:

and the DCS controller scans the signal collector group in real time and controls the compressor unit to enter a starting process, a loading process, an unloading process or a stopping process according to data fed back by the signal collector group.

Further, the starting procedure comprises the following steps:

step S11: if the DCS controller receives an interlocking starting instruction F_ROr receiving a start control signal K_RThe DCS controller sends out a control signal K of the main motor contactor_MMain motor star contactor control signal K_SCooling fan contact control signal K_FThereby starting the main motor, the star-shaped loop of the main motor and the cooling fan motor; wherein the interlock starts the instruction

I.e. compressed gas main pipe pressure transmitter P₂When the deviation is lower than the set value, the phase sequence protector PH, the thermocouple relay TH and the temperature switch TS of the main motor are not closed, and the feedback contact C of the main contactor_MThe disconnection time meets a set value;

step S12: after the star-shaped loop of the main motor is started, if the DCS controller receives a switching permission instruction F of the main motor loop_ΔThe DCS controller sends out the triangular contactor control of the main motorSystem signal K_DAnd the star contactor control signal K of the main motor is cut off_SSwitching the star-shaped loop of the main motor into a triangular loop to complete the starting of the compressor unit; wherein

That is, the phase sequence protector PH, the thermocouple relay TH and the main motor temperature switch TS are not actuated, and the main contactor feedback contact C_MStar-shaped contactor feedback contact C_SThe closing time meets the set value, and the signal quality of the current transducer I of the main motor is good.

Further, the shutdown process comprises the following steps:

step S21: if the DCS controller receives an electric protection shutdown loop instruction F_SEThermal protection shutdown loop instruction F_STOr automatic shutdown loop command F_SAThe DCS controller sends an unloading instruction, a locking loading instruction and a locking output adjusting instruction, and disconnects a main motor contactor control signal K_MMain motor star contactor control signal K_SControl signal K of triangular contactor of main motor_DCooling fan contact control signal K_FStopping the compressor unit; wherein F_SE＝TH+C_E+ PH + TS, i.e. thermocouple relay TH, emergency stop button feedback contact C_EAt least one action of the phase sequence protector PH and the main motor temperature switch TS; f_ST＝OT₁+OP₁I.e. exhaust port temperature sensor T₁Exceeding the shut-down protection set value, or the exhaust port pressure transmitter P₁Exceeding the set shutdown protection value;

namely, the closing time of the control signal of the bleed-off electromagnetic valve meets the set value and the compressed gas main pipe pressure transmitter P₂The deviation is not lower than a set value;

or when the DCS controller receives the stop control signal K_TThe DCS controller sends an unloading instruction, continuously unloads and locks loading and output adjustment, and when the pressure transmitter P of the separator is used₃Control signal K below set value or discharging solenoid valve_UWhen the continuous on-time reaches the set value, the main motor contactor control signal K is switched off_MMain motor star contactor control signal K_SControl signal K of triangular contactor of main motor_DCooling fan contact control signal K_FAnd stopping the compressor unit.

Further, the loading process comprises the following steps:

step S31: if the DCS controller receives a load permission instruction F_LThe DCS controller sends out a control signal K for loading the electromagnetic valve_LSwitching on the loading gas circuit and switching off the control signal K of the bleed solenoid valve_UWherein

Instant stop instruction F_SOn the premise of not triggering, the air compressor is started to complete the star-delta switching for the first time, or the pressure transmitter P at the air outlet₁The loading threshold is reduced and the main motor completes the star-delta switching;

step S32: after the loading gas circuit is connected, if the DCS controller receives a loading adjustment permission instruction F_CIf yes, the DCS controller is allowed to send out an electric regulating valve control command V_SAt this time, the electric control valve control instruction V_SAs output variable and controlled variable P₁A PID operation loop is adopted to realize the loading regulation of the air compressor; wherein F_C＝F_L·ΔP₁·Q_I·Q_VI.e. load-enable instruction F_LPresence and exhaust port pressure transmitter P₁The deviation exceeds the regulation dead zone, the signal quality of the current transducer I of the main motor is good, and the position feedback V of the electric regulating valve_ZThe signal quality is good.

Further, the unloading process comprises the following steps:

step S41: if the DCS controller receives the interlocking unloading instruction F_UIf so, the DCS controller sends out a control signal K of the discharge solenoid valve_USwitching on the unloading gas path and switching off the control signal K of the loading solenoid valve_LThe unloading of the air compressor is realized; wherein

I.e. the main motor has been started but not completed the star-delta switching, or the exhaust port pressure transmitter P₁Rising to the unloading threshold value and finishing star-delta switching by the main motor to start acting or stopping command F_SAre present.

According to the energy-saving air compressor control system based on DCS comprehensive control, the running state of the compressor set is monitored by installing the signal collector group on the compressor set; the DCS controller is adopted to periodically scan the signal collector group so as to obtain the current running state of the compressor unit in real time, and a corresponding DCS control strategy is formulated, so that the compressor unit can switch the working procedures of running starting, loading, unloading, stopping and the like according to the working conditions, the running of the compressor unit is more reasonable, and the running energy consumption of the compressor unit can be reduced; meanwhile, data obtained by scanning of the DCS controller can be stored in a DCS historical database, so that the historical working condition of the equipment in any period of the whole life cycle can be read back, and the requirements of fault analysis and equipment optimization are fully met.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an energy-saving air compressor control system based on DCS overall control according to the present invention;

FIG. 2 is a schematic flow chart of a start-up procedure provided by the present invention;

FIG. 3 is a schematic flow chart of a stopping process provided by the present invention;

FIG. 4 is a schematic flow chart of a loading process provided by the present invention;

FIG. 5 is a schematic flow chart of an unloading process provided by the present invention;

FIG. 6 is a logic diagram of a start-up procedure and a stop procedure provided by the present invention;

fig. 7 is a logic diagram of a loading process and an unloading process according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Moreover, the use of "first," "second," and similar language does not denote any order, quantity, or importance, but rather the components are distinguished. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

As shown in fig. 1, the invention provides an energy-saving air compressor control system based on DCS overall control, which includes a compressor unit, an electrical unit, a signal collector group and a DCS control unit; the signal collector group is used for monitoring the running states of the electrical unit and the compressor unit; the DCS control unit sends out different control instructions according to the information fed back by the signal collector group; and the electrical unit controls the compressor unit to start, load, unload or stop according to the instruction sent by the DCS control unit.

In specific implementation, as shown in fig. 1, the compressor unit includes an air filter, an electric control valve, a pneumatic valve, a compressor, an oil-gas barrel separator, an oil filter, a cooler, and an outlet screw valve; the air filter, the electric regulating valve, the pneumatic valve, the compressor, the oil-gas barrel separator cooler and the outlet screwing valve are connected to a compressed gas main pipe in sequence to form a compressed gas circuit; after being filtered by an air filter, the outside air enters the compressor through an electric regulating valve and an air inlet pipeline where a pneumatic valve is arranged; the oil-gas mixed compressed gas is formed under the action of a compressor, and the oil-gas mixed compressed gas passes through an oil-gas barrel separator to form compressed air and lubricating oil; compressed air is output from an outlet pipe of the oil-gas barrel separator, is cooled by a cooler and then enters a compressed air main pipe through an outlet screwing valve to be supplied to a user; the lubricating oil separated by the oil-gas barrel separator is cooled by a cooler and filtered by an oil filter, and then returns to the compressor to continuously support compression and do work; preferably, the cooler is a closed water cooler.

As shown in fig. 1, the top of the oil-gas barrel separator is connected to the pneumatic valve through a discharge solenoid valve to form a discharge gas path; an outlet pipe of the oil-gas barrel separator is connected to a driving cylinder of the pneumatic valve through a loading electromagnetic valve to form a loading gas circuit.

As shown in fig. 1, the electric unit includes a power supply terminal, an emergency stop button, a main motor contactor M, a main motor star-shaped contactor S, and a main motor delta-shaped contactor D for controlling power supply of the compressor motor, a cooling fan contactor F for controlling power supply of the cooling fan motor, and three electric branches for controlling power supply of the electric control valve, the bleed-off solenoid valve, and the load solenoid valve, respectively; when the star-shaped contactor of the main motor works, a power supply loop of the main motor is in a star-shaped connection mode; when the triangular contactor of the main motor works, the power supply loop of the main motor is in a triangular connection mode; the emergency stop button is connected in series between the power supply end and the main motor contactor M, the main motor star-shaped contactor S, the main motor triangular contactor D and the cooling fan contactor F, and when the emergency stop button is disconnected, the main motor contactor M, the main motor star-shaped contactor S, the main motor triangular contactor D and the cooling fan contactor F are all powered off to stop working.

As shown in FIG. 1, the signal acquisition device group includes, but is not limited to, an air-filter differential pressure switch PS₁A main motor temperature switch TS, a main motor current transducer I, a thermocouple relay TH, a phase sequence protector PH, an oil filtration pressure difference switch PS₂Separator pressure transmitter P₃Separator temperature sensor T₂Exhaust port temperature sensor T₁Exhaust port pressure transmitter P₁Closed water pressure transmitter P₄Pressure transmitter P of compressed gas main pipe₂Position feedback V of electric regulating valve_ZMain motor contactor feedback contact C_MFeedback contact C of star-type contactor of main motor_SFeedback contact C of triangular contactor of main motor_DCooling fan contactor feedback contact C_FAnd scram button feedback contact C_E。

Wherein, the air filter differential pressure switch PS₁For detecting whether the air filter is clogged; the main motor temperature switch TS is arranged near the main motor of the compressor, and is disconnected when the temperature of the main motor reaches a set threshold value; the main motor current transmitter I, the thermocouple relay TH and the phase sequence protector PH are all connected in series on a power supply loop of a main motor of the compressor, the main motor current transmitter I is used for detecting the power supply current of the main motor, the thermocouple relay TH is used for disconnecting the power supply of the main motor when the power supply current of the main motor is too large, and the phase sequence protector PH is used for disconnecting the power supply of the main motor when the power supply phase sequence connected into the main motor is wrong.

Oil filter differential pressure switch PS₂For detecting whether the oil filter is clogged; separator pressure transmitter P₃Separator temperature sensor T₂The device is respectively used for detecting the internal air pressure of the oil-gas barrel separator and the temperature of the oil-gas barrel separator; exhaust port temperature sensor T₁Exhaust port pressure transmitter P₁The temperature and the air pressure of the exhaust port are respectively used; closed water pressure transmitter P₄The pressure sensor is used for detecting the internal pressure of a cooling water pipeline of the cooler; compressed gas main pipe pressure transmitter P₂The air pressure detection device is used for detecting the internal air pressure of the compressed air main pipe.

The DCS control unit comprises a DCS controller, an input module, an output module and a human-computer interface; the human-computer interface comprises but is not limited to a starting control signal input interface, a stopping control signal input interface, an electric control valve control instruction input interface and a display interface, and the input module, the output module and the human-computer interface are electrically connected with the DCS controller. Wherein the start control signal input interface is used for inputting a start control signal K to the DCS controller_RA stop control signal input interface for inputting a stop control signal K to the DCS controller_TThe electric control valve control instruction input interface is used for inputting an electric control valve control instruction V to the DCS controller_S(ii) a The starting control signal input interface, the stopping control signal input interface and the electric control valve control instruction input interface can be electric switch elements such as keys and buttons which are electrically connected with the DCS controller, and can also be virtual input interfaces integrated on a display interface.

Display interface comprehensive display main motor current transducer I and separator pressure transducer P₃Separator temperature sensor T₂Exhaust port temperature sensor T₁Exhaust port pressure transmitter P₁Closed water pressure transmitter P₄Pressure transmitter P of compressed gas main pipe₂Position feedback V of electric regulating valve_ZMain motor contactor feedback contact C_MFeedback contact C of star-type contactor of main motor_SFeedback contact C of triangular contactor of main motor_DCooling fan contactor feedback contact C_FEmergency stop button feedback contact C_EAnd the signals are used as an air compressor state display query interface, and meanwhile, an alarm pop-up window body can be generated on the display interface to summarize and display the air filter differential pressure switch PS₁Emergency stop button feedback contact C_ETemperature switch TS of main motor, thermocouple relay TH, phase sequence protector PH and oil filtration differential pressure switch PS₂And waiting for a fault signal alarm.

In the embodiment of the invention, the air filter differential pressure switch PS₁Temperature switch TS of main motor, thermocouple relay TH, phase sequence protector PH and oil filtration differential pressure switch PS₂Main motor contactor feedback contact C_MStar type of main motorContactor feedback contact C_SFeedback contact C of triangular contactor of main motor_DCooling fan contactor feedback contact C_FEmergency stop button feedback contact C_EAccessing a DCS switching value input module;

main motor current transducer I, separator pressure transducer P₃Separator temperature sensor T₂Exhaust port temperature sensor T₁Exhaust port pressure transmitter P₁Closed water pressure transmitter P₄Pressure transmitter P of compressed gas main pipe₂Position feedback V of electric regulating valve_ZAccessing a DCS analog quantity input module;

the functional logic module can output a main motor contactor control signal K through the DCS switching value output module_MMain motor star contactor control signal K_SControl signal K of triangular contactor of main motor_DCooling fan contact control signal K_FAnd a discharge solenoid valve control signal K_ULoad the control signal K of the electromagnetic valve_LOutputting a control instruction V of the electric control valve through a DCS analog quantity output module_S。

Specifically, the DCS controller performs cyclic scanning on the signal collector group at a fixed period of less than 1 second, stores data obtained through scanning into a DCS historical database, sets the data to be stored for a certain time (such as 2190 days), realizes the reading back of historical working conditions at any time period in the whole life cycle of the equipment, and fully meets the requirements of fault analysis and equipment optimization.

As shown in fig. 2, the start-up process of the present invention comprises the steps of:

step S11: if the DCS controller receives the interlocking start fingerLet F_ROr receiving a start control signal K_RThe DCS controller sends out a control signal K of the main motor contactor_MMain motor star contactor control signal K_SCooling fan contact control signal K_FThereby starting the main motor, the star-shaped loop of the main motor and the cooling fan motor; wherein the interlock starts the instruction

I.e. compressed gas main pipe pressure transmitter P₂When the deviation is lower than the set value, the phase sequence protector PH, the thermocouple relay TH and the main motor temperature switch TS are not closed, and the feedback contact C of the main contactor_MThe disconnection time meets a set value;

as shown in fig. 6, when step S11 is implemented, the main contactor feedback contact C_MEntering a first TD _ ON lag position type timer functional block through a first NOT logic non functional block, and sending a main contactor feedback contact C with a value of 1 after judging that the duration is greater than a set value (such as 60S)_MOff-time satisfaction signal

The temperature switch TS of the main motor enters a second AND logic AND function block together through a second NOT logic non-function block, a thermocouple relay TH passes through a third NOT logic non-function block AND a phase sequence protector PH passes through a fourth NOT logic non-function block, AND a protection tripping non-signal with the value of 1 is sent out when the temperature switch TS, the thermocouple relay TH AND the phase sequence protector PH are all 0

Compressed gas main pipe pressure transmitter P₂The fourth HLALM high-low limit judgment module judges that the pressure of the compressed gas main pipe is low_2L(e.g. below 730Kpa) and DCS picture start control signal K_RThe output signals of the first OR logic OR function block and the feedback contact C of the main contactor_MOff-time satisfaction signal

And protection trip non-signal

Sending an interlocking start instruction with the value of 1 to the EMD1 override input pin when the first AND logic AND function block AND the first DEVICE digital manual operator function block are all 1, AND forcing the first DEVICE digital manual operator function block OUT1 to output an air compressor start instruction F with the output value of 1 on the output pin_STRSending the signal to the setting end of the first RS trigger functional block to send a main motor contactor control signal K_MCooling fan contact control signal K_FAnd sends out a control signal K of the star-shaped contactor of the main motor through a setting end of a second RS trigger functional block_SAnd starting the air compressor in a star shape. Simultaneous main contactor C_MOff-time satisfaction signal

And protection trip non-signal

The third AND logic AND function block is commonly fed in, AND then as a start enable signal into the D1P pin of the first DEVICE digital hand operator function block, thereby enabling the OUT1 output pin output.

Step S12: after the star-shaped loop of the main motor is started, if the DCS controller receives a switching permission instruction F of the main motor loop_ΔThe DCS controller sends out a control signal K of the triangular contactor of the main motor_DAnd the star contactor control signal K of the main motor is cut off_SSwitching the star-shaped loop of the main motor into a triangular loop to complete the starting of the compressor unit; wherein

Namely, the phase sequence protector PH, the thermocouple relay TH and the main motor temperature switch TS are not triggered to perform protection actions, and the feedback contact C of the main contactor_MStar-shaped contactor feedback contact C_SThe closing time meets the set value, and the signal quality of the current transducer I of the main motor is good; in the embodiment of the invention, the good signal quality of the current transducer I of the main motor indicates the current of the main motorThe current value detected by the transmitter I is within a set current range.

As shown in fig. 6, in the specific implementation of step S12, the current value I detected by the main motor current transmitter I is determined by the first HLALM high/low limit determining module, and is output from the pin D of the first HLALM high/low limit determining module to the twelfth NOT logic non-functional block, if the main motor current is in the set current range (for example, 350 f)>I>50) Sending a main motor current quality signal Q with a value of 1_I(ii) a Main contactor feedback contact C_MFeedback contact C with star contactor_SAfter the judgment of the fourth AND logic AND function block, a star starting feedback signal is output to the first Timer function block, a Boolean signal with the value of 1 is sent out after 8 seconds of timing, AND the Boolean signal AND a protection trip non-signal are sent out

And main motor current quality signal Q_IThe three signals jointly enter a fifth AND logic AND functional block, AND when the input signals of the fifth AND logic AND functional block are all 1, a main motor loop switching permission instruction with the value of 1 is sent out

Main motor loop switching permission command F_△And an air compressor shutdown instruction F_STP(see step S21 described later in detail) the seventh OR logic OR function block is jointly fed, and when any signal is 1, a Boolean quantity with the value of 1 is sent to the reset end of the second RS trigger function block to disconnect the star-shaped contactor control signal K of the main motor_SMain motor loop switching permission command F_△Simultaneously sends the signals to a set end of a third RS trigger to output a control signal K of the triangular contactor of the main motor_DAnd finishing the switching of the star-delta starting mode of the air compressor.

As shown in fig. 3, the shutdown process of the present invention comprises the steps of:

step S21: if the DCS controller receives an electric protection shutdown loop instruction F_SEThermal protectionStall loop instruction F_STOr automatic shutdown loop command F_SAThe DCS controller sends an unloading instruction and disconnects a main motor contactor control signal K_MMain motor star contactor control signal K_SControl signal K of triangular contactor of main motor_DCooling fan contact control signal K_FStopping the compressor unit; wherein the electrical protection is stopped the loop command F_SE＝TH+C_E+ PH + TS, i.e. thermocouple relay TH, emergency stop button feedback contact C_EAt least one trigger protection action is arranged in the phase sequence protector PH and the main motor temperature switch TS; thermotechnical protection shutdown loop instruction F_ST＝OT₁+OP₁I.e. the exhaust port temperature sensor T1 exceeds the shut down protection set point, or the exhaust port pressure transmitter P₁Exceeding the set shutdown protection value; automatic shutdown loop instruction

or if the DCS controller receives the stop control signal K_TAnd the DCS controller sends an unloading instruction, continuously unloads and locks loading and output regulation. When the pressure transmitter P of the separator₃Control signal K below set value or discharging solenoid valve_UWhen the continuous on-time reaches the set value, the main motor contactor control signal K is switched off_MMain motor star contactor control signal K_SControl signal K of triangular contactor of main motor_DCooling fan contact control signal K_FAnd stopping the compressor unit.

Preferably, the thermocouple relay TH and the emergency stop button are connected in series between the power supply terminal and each contactor, and when the thermocouple relay TH and the emergency stop button are triggered, the main motor contactor M, the main motor star-shaped contactor S, and the main motor delta-shaped contactor D are powered off and disconnected.

As shown in FIG. 6, when step S21 is embodied, the scram button contact C_ETS signal and thermocouple relay connected with main motor temperature switchThe TH signal and the PH signal of the phase sequence protector enter a second OR logic OR functional block together, and any input signal of the second OR logic OR functional block is 1, and the output value of the electrical protection shutdown loop instruction F is 1_SE. Exhaust port temperature sensor T₁Pressure transmitter P with exhaust port₁Respectively sending the judgment results of the second HLALM high-low limit judgment functional block and the third HLALM high-low limit judgment functional block into a third OR logic OR functional block, and outputting a thermal protection shutdown loop instruction F with an output value of 1 if any signal of the two functional blocks is 1_ST。

Compressed gas main pipe pressure transmitter P₂The fourth HLALM high-low limit judgment functional block judges and outputs a compressed air main pipe pressure low signal P_2LAfter passing through a fifth NOT logic non-function block, outputting a low-pressure non-signal of a compressed air main pipe

Control signal K for opening discharge solenoid valve_UAfter the second TD _ ON hysteresis setting type timer function block judges that the duration is greater than the set value (for example, 600 seconds), the opening duration satisfying signal dTK of the bleed solenoid valve with the value of 1 is sent_UAnd is and

jointly enter a sixth AND logic AND functional block, AND send out an automatic shutdown loop instruction F with the value of 1 when the input signals are all 1_SA。F_SE、F_ST、F_SAJointly enter a fourth OR logic OR function block, and output a shutdown command F if any input signal is 1_S。

Halt instruction F_SAnd DCS picture stop control signal K_TThe input signals of the first AND second AND logic AND function blocks are input into a fifth OR logic OR function block together, AND when any input signal is 1, a boolean signal with the value of 1 is output, as shown in fig. 7, the boolean signal, an output signal of an eleventh AND logic AND function block AND an output signal of a twelfth AND logic AND function block are input into a tenth OR logic OR function block together, AND after the output signal of the tenth OR logic OR function block passes through the eleventh OR logic OR function block, the output signal enters a first PID operation function block to lock an input pin so as to lock the control command V of the electric control valve_S(ii) a Meanwhile, the output signal of the tenth OR logic OR function block also enters a second EMD2 override input pin of a second DEVICE digital manual operator function block, the Boolean quantity with the output value of 1 of the output pin of the second DEVICE digital manual operator function block OUT2 is forced to be sent to the reset end of a fourth RS trigger function block and the set end of a fifth RS trigger function block, and a control signal K for opening and discharging the electromagnetic valve is sent_UAnd disconnect the control signal K of the loading electromagnetic valve_L。

Bleed solenoid valve control signal K_UEntering a third TD _ ON lag set type timer function block, judging whether the duration is greater than a set value (such as 15 seconds), sending a shutdown unloading time satisfying signal with a value of 1, and sending a pressure transmitter P of the separator₃When the output value is less than the set value (for example, 150Kpa) through the fifth HLALM high-low limit judgment functional block, outputting a Boolean signal with the value of 1, and enabling the Boolean signal and the set value to jointly enter an eighth OR logic OR functional block; if any input signal of the eighth OR logic OR functional block is 1, outputting a Boolean signal with the value of 1; the output signal of the eighth OR logic OR function block and the DCS picture stop control signal K_TJointly enter a seventh AND logic AND function block, AND when the input signals of the seventh AND logic AND function block are both 1, the seventh AND logic AND function block sends out a stop control low signal K with the value of 1 for disconnecting the main contactor_TL。

Halt instruction F_SAnd stop control low signal K_TLJointly enter a sixth OR logic OR function block, and if any input signal is 1, a Boolean quantity signal with the value of 1 is output to a second EMD2 override input pin of the first DEVICE digital manual operator function block to force the first DEVICE digital manual operator function block OUT2 to output an air compressor shutdown command F with the output pin of 1_STPAir compressor stop command F_STPSending a control signal K to a reset end of a first RS trigger functional block to disconnect a main motor contactor_MContact control signal K with cooling fan_FAir compressor stop command F_STPMeanwhile, the control signal K is also sent to the reset end of the third RS trigger functional block to disconnect the triangle contactor control signal K of the main motor_D(ii) a Air compressor shutdown instruction F_STPSwitching with Main Motor Loop Enable instruction F_△Sending the signals into a seventh OR logic OR function block together, and sending a Boolean quantity with the value of 1 to the second RS trigger when any signal is 1Star-shaped contactor control signal K for disconnecting main motor at energy block reset end_SAnd the main motor contactor, the main motor star-shaped contactor, the main motor triangular contactor and the cooling fan are disconnected in contact, so that the compressor unit is stopped.

As shown in fig. 4, the loading process of the present invention comprises the steps of:

step S31: if the DCS controller receives the interlocking loading instruction, the DCS controller sends out a loading electromagnetic valve control signal K_LSwitching on the loading gas circuit and switching off the control signal K of the bleed solenoid valve_UWherein

Namely, on the premise that the stop command FS is not triggered, the air compressor is started to complete star-delta switching for the first time, or the air outlet pressure transmitter P₁The loading threshold is reduced and the main motor completes the star-delta switching;

as shown in FIG. 7, in step S31, the vent pressure transmitter P is implemented₁When the exhaust port pressure is judged to be lower than the set value (for example, 750Kpa), the sixth HLALM high-low limit judgment function block sends an exhaust port pressure low signal P with the value of 1_1L. Main contactor feedback contact signal C_MFeedback contact C of triangular contactor of main motor_DSending the signals C of the main motor star-delta switching completion with the value of 1 when the signals are all 1_Δ. Halt instruction F_S+K_TSignal after passing through sixth NOT logic non-function block, exhaust port pressure low signal P_1LAnd a main motor star-delta switching completion signal C_ΔEnter the tenth AND logical AND function block together. Feedback contact C of star-shaped contactor of main motor_SSending into a first TD _ OFF hysteresis reset type timer function block, and judging the feedback contact C of the star-shaped contactor of the main motor_SSending out a Boolean signal with a value of 1 second after disappearance, wherein the Boolean signal and a feedback contact signal C of the triangular contactor_DHalt instruction F_S+K_TAND the signals after passing through the first NOT logic non-functional block enter a ninth AND logic AND functional block together. The ninth AND logic AND function block judgment result AND the tenth AND logic AND function block judgment result are the sameThe same goes into a ninth OR logic OR functional block, any input signal of which is 1, and the interlocked load instruction F with the output value of 1_LThe first EMD1 override input pin to the second DEVICE digital manual operator function block forces the output value of the output pin of the second DEVICE digital manual operator function block OUT1 to be 1 Boolean quantity to be sent to the set end of the fourth RS trigger function block and the reset end of the fifth RS trigger function block, and sends OUT a control signal K for loading an electromagnetic valve_LAnd disconnecting the bleed solenoid control signal K_U。

Step S32: after the loading gas circuit is connected, if the DCS controller receives a loading adjustment permission instruction F_CIf yes, the DCS controller is allowed to send out an electric regulating valve control command V_SAt this time, the electric control valve control instruction V_SAs output variable and controlled variable P₁A PID operation loop is adopted to realize the loading of the air compressor; wherein F_C＝F_L·ΔP₁·Q_I·Q_VI.e. load-enable instruction F_LPresence and exhaust port pressure transmitter P₁The deviation exceeds the regulation dead zone, the signal quality of the current transducer I of the main motor is good, and the position feedback V of the electric regulating valve_ZThe signal quality is good.

As shown in FIG. 7, in step S32, the vent pressure transmitter P is implemented₁Sending the set value SP of the outlet pressure of the air compressor and the set value SP of the outlet pressure of the air compressor into a first DEV deviation operation functional block, carrying out nonlinear calculation on the deviation value of the set value and the actual exhaust pressure, outputting a calculated value Y to be used as a main regulation quantity of a first PID operation functional block to participate in PID operation, and finally outputting a control command V of an electric regulating valve_SAnd the loading output of the air compressor is precisely adjusted. In the embodiment of the invention, the control instruction V of the electric regulating valve_SThe PID operation loop of (1) can adopt a PID operation loop similar to a slow electric regulation stage in a patent application (with the publication number of CN109026688A) already filed by the applicant.

Electric regulator valve position feedback V_ZJudging the signal quality through a first TQ quality judgment function block, and sending the signal quality to a tenth NOT logic non-function block; the current I of the main motor is judged to be signal quality through the second TQ quality judgment functional block and is sent to the eleventh NOT logic non-functional block; pressure P of exhaust port₁With air pressureThe set value SP of the machine outlet pressure is calculated and judged by the first DEV deviation operation functional block, and then an out-of-limit judgment signal (such as lower than-10 Kpa or higher than 10Kpa) is output and sent to the ninth NOT logic non-functional block; load enable instruction F_LA signal after passing through the seventh NOT logic NOT function block, and an interlock unload instruction signal F output from the tenth OR logic OR function block_UAnd the output signal of the ninth NOT logic non-function block, the output signal of the tenth NOT logic non-function block and the output signal of the eleventh NOT logic non-function block enter an eleventh OR logic OR function block together, and if any input signal of the eleventh OR logic OR function block is 1, a locking instruction is output to the locking input pin of the first PID operation function block to lock the control function of the electric regulating valve.

It should be noted that good signal quality in the embodiments of the present invention means that the current signal or the pressure signal detected by the transmitter is within a set value range.

As shown in fig. 5, the unloading process of the present invention includes the following steps:

That is, the main motor has started but did not complete the star-delta switch, or the exhaust port pressure transmitter P1 rises to the unload threshold and the main motor completes the star-delta switch to begin doing work, or the shutdown command FS exists.

As shown in FIG. 7, in step S41, the vent pressure transmitter P is implemented₁Sending a pressure high signal P with a value of 1 when the exhaust port pressure is judged to be higher than the unloading threshold (such as 830Kpa) through a sixth HLALM high-low limit judgment function block_1HSignal C for completing star-delta switching with main motor_ΔEnter the eleventh AND logical AND function block together. Main contactor feedback contact signal C_MTriangle type contactor feedback contact C_DSignals passing through the eighth NOT logic non-functional block and a contact signal C fed back by the star contactor_SEnter the twelfth AND logical AND function block together. An output signal of the eleventh AND logic AND function block, an output signal of the twelfth AND logic AND function block AND the halt instruction F_S+K_TEnter the tenth OR logic OR function block together, any input signal of which is 1 will output the interlocking unload instruction F with 1_UThe second DEVICE digital manual operator function block EMD2 overrides the input pin, forces the output value of the output pin of the second DEVICE digital manual operator function block OUT2 to be 1 Boolean quantity to be sent to the reset end of the fourth RS trigger function block and the set end of the fifth RS trigger function block, and sends OUT a control signal K for opening and discharging the electromagnetic valve_UAnd disconnect the control signal K of the loading electromagnetic valve_L。

When the energy-saving modification of the existing air compressor system is carried out, according to the structural schematic diagram of the energy-saving air compressor control system based on the DCS comprehensive control shown in the figure 1, the existing air compressor system is modified, the electric control system of the existing air compressor system is removed to replace the electric unit and the signal collector group provided by the embodiment of the invention, so that the electric unit is connected with the output module of the DCS control unit, the signal collector group is connected with the input module of the DCS control unit, and the output module and the input module are electrically connected with the DCS controller through signal cables; and change the partial structure of air compressor machine system, if change the pressure sensor that current air compressor machine system generally adopted for standard pressure transmitter, will hold the accent valve, shuttle valve and change for electrical control valve, pneumatic valve etc. above-mentioned transformation need not to change the main part of current air compressor machine system, consequently can greatly reduce the cost of energy-conserving transformation.

In order to further verify the actual energy-saving effect of the energy-saving air compressor control system and method based on DCS comprehensive control provided by the invention, the practical tests are carried out in company A: an air compressor station formed by 4 air compressors of company A is improved, and the air compressor of company A is a screw compressor of SA-185W/0.85 type of Kanshiza, Guangdong; the company A has an industrial DCS control system consisting of GE Xinhua OCE6000 type controllers, and one set of control units are selected as DCS control units; the logic function blocks of the control module and the configuration software language adopted by each DCS strategy in the DCS control unit are all universal, the method can be realized by increasing, decreasing and replacing logic function blocks of similar control modules and configuration software languages in other domestic and foreign brand types of DCS systems, the implementation cost is 35 ten thousand yuan in total, after 2 months of continuous operation, electricity is saved by 648 degrees every day, the accumulated recovery cost is 1.9 ten thousand yuan, all the modification cost can be recovered within 3 years, the stable operation period of the modified equipment is estimated to be about 10 years, and the energy-saving benefit is extremely obvious.

Although terms such as air compressor, DCS, sensors, pressure transducers, electrically operated regulator valves, pneumatic valves, chiller solenoid valves, oil and gas barrel separators are used more often herein, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. The energy-saving air compressor control method based on DCS comprehensive control is characterized by comprising the following steps: the system comprises a compressor unit, an electrical unit, a signal collector group and a DCS control unit; the signal collector group is used for monitoring the running states of the electrical unit and the compressor unit; the DCS control unit sends out different control instructions according to the information fed back by the signal collector group; the electrical unit controls the compressor unit to start, load, unload or stop according to the instruction sent by the DCS control unit;

the method comprises the following steps:

scanning the signal collector group in real time through a DCS controller, and controlling the compressor unit to enter a starting process, a loading process, an unloading process or a stopping process according to data fed back by the signal collector group through the DCS controller;

the starting procedure comprises the following steps:

step S12: after the star-shaped loop of the main motor is started, if the DCS controller receives a switching permission instruction F of the main motor loop_ΔThe DCS controller sends out a control signal K of the triangular contactor of the main motor_DAnd is disconnectedMain motor star contactor control signal K_SSwitching the star-shaped loop of the main motor into a triangular loop to complete the starting of the compressor unit; wherein

That is, the phase sequence protector PH, the thermocouple relay TH and the main motor temperature switch TS are not actuated, and the main contactor feedback contact C_MStar-shaped contactor feedback contact C_SThe closing time meets the set value, and the signal quality of the current transducer I of the main motor is good;

the shutdown process comprises the following steps:

or when the DCS controller receives the stop control signal K_TThe DCS controller sends an unloading instruction, continuously unloads and locks loading and output adjustment, and when the pressure transmitter P of the separator is used₃Control signal K below set value or discharging solenoid valve_UThe continuous on-time reaches toConstant value, cut-off main motor contactor control signal K_MMain motor star contactor control signal K_SControl signal K of triangular contactor of main motor_DCooling fan contact control signal K_FStopping the compressor unit;

the loading process comprises the following steps:

step S32: after the loading gas circuit is connected, if the DCS controller receives a loading adjustment permission instruction F_CIf yes, the DCS controller is allowed to send out an electric regulating valve control command V_SAt this time, the electric control valve control instruction V_SAs output variable and controlled variable P₁A PID operation loop is adopted to realize the loading regulation of the air compressor; wherein F_C＝F_L·ΔP₁·Q_I·Q_VI.e. load-enable instruction F_LPresence and exhaust port pressure transmitter P₁The deviation exceeds the regulation dead zone, the signal quality of the current transducer I of the main motor is good, and the position feedback V of the electric regulating valve_ZThe signal quality is good;

the unloading process comprises the following steps:

I.e. masterThe machine has been started but has not completed star-delta switching, or the exhaust port pressure transmitter P₁Rising to the unloading threshold value and finishing star-delta switching by the main motor to start acting or stopping command F_SAre present.

2. The DCS comprehensive control-based energy-saving air compressor control method of claim 1, wherein the method comprises the following steps: the compressor unit comprises an air filter, an electric regulating valve, a pneumatic valve, a compressor, an oil-gas barrel separator, an oil filter, a cooler and an outlet screwing valve; the air filter, the electric regulating valve, the pneumatic valve, the compressor, the oil-gas barrel separator cooler, the outlet screwing valve and the compressed gas main pipe are sequentially connected to form a compressed gas circuit; the top of the oil-gas barrel separator is connected to the front of the pneumatic valve through a discharge solenoid valve to form a discharge gas path; and an outlet pipe of the oil-gas barrel separator is connected to a driving cylinder of the pneumatic valve through a loading electromagnetic valve to form a loading gas circuit.

3. The DCS comprehensive control-based energy-saving air compressor control method of claim 2, wherein the method comprises the following steps: the electric unit comprises a power supply end, an emergency stop button, a main motor contactor, a main motor star-shaped contactor and a main motor triangular contactor, wherein the main motor contactor, the main motor star-shaped contactor and the main motor triangular contactor are used for controlling the power supply of the compressor motor, a cooling fan contactor is used for controlling the power supply of the cooling fan motor, and three electric branches are respectively used for controlling the power supply of the electric regulating valve, the release electromagnetic valve and the loading electromagnetic valve.

4. The DCS comprehensive control-based energy-saving air compressor control method of claim 1, wherein the method comprises the following steps: the signal acquisition element group comprises but is not limited to an air filtering differential pressure switch PS₁A main motor temperature switch TS, a main motor current transducer I, a thermocouple relay TH, a phase sequence protector PH, an oil filtration pressure difference switch PS₂Separator pressure transmitter P₃Separator temperature sensor T₂Exhaust port temperature sensor T₁Exhaust port pressure transmitter P₁Closed water pressure transmitter P₄Pressure transmitter P of compressed gas main pipe₂Position feedback V of electric regulating valve_ZMain motor contactor feedback contact C_MFeedback contact C of star-type contactor of main motor_SFeedback contact C of triangular contactor of main motor_DCooling fan contactor feedback contact C_FAnd scram button feedback contact C_E。

5. The DCS comprehensive control-based energy-saving air compressor control method of claim 1, wherein the method comprises the following steps: the DCS unit comprises a DCS controller, an input module, an output module and a human-computer interface; the human-computer interface comprises but is not limited to a starting control signal input interface, a stopping control signal input interface, an electric control valve control instruction input interface and a display interface.