阅读说明：本技术 一种苛化绿液系统变频调节的控制方法 (Control method for frequency conversion adjustment of causticized green liquor system ) 是由 林为军 王志良 陆依标 邹运通 于 2019-11-06 设计创作，主要内容包括：本发明公开了一种苛化绿液系统变频调节的控制方法,是对苛化绿液系统变频进行改造,利用变频器的无级调速对原绿液系统的电动阀门控制方式进行取代,解决了阀门开度量调节困难,误差大,精度低,绿液输送管道易结垢,绿液槽液位难以控制等诸多技术问题。(The invention discloses a control method for frequency conversion regulation of a causticized green liquor system, which is used for transforming the frequency conversion of the causticized green liquor system and replacing an electric valve control mode of an original green liquor system by utilizing the stepless speed regulation of a frequency converter, and solves the technical problems of difficult regulation of the opening degree of a valve, large error, low precision, easy scaling of a green liquor conveying pipeline, difficult control of the liquid level of a green liquor tank and the like.)

1. A control method for frequency conversion adjustment of a causticized green liquor system is characterized by comprising the following steps:

(1) centralized control: namely, the console is used for remote control;

(2) machine-side control: the motor is turned on or off on the motor field control box;

(3) the frequency conversion cabinet can input and output the following signals:

1) frequency conversion cabinet switching value input signal: the frequency converter is driven, namely a passive contact is closed to start, and the vehicle is cut off to stop;

2) frequency conversion cabinet speed given signal: 4-20 mADC, and giving a signal at a speed;

3) the frequency conversion cabinet at least outputs the following signals:

① running system, frequency conversion speed regulation device running signal;

② failure alarm, wherein the frequency conversion speed regulation control device stops the alarm signal of the main motor;

③, feeding back a motor rotating speed signal of 4-20 mADC;

④, feeding back current of 4-20 mADC and motor current signals;

4) step 1), all switching value contacts are passive contacts, the contact capacity is not less than 3A/220VAC, all analog values are 4-20 mADC signals, and a signal isolator is added in a variable-frequency speed-regulating switch cabinet;

(4) the front side of the variable frequency speed regulation switch cabinet is provided with a power frequency-variable frequency selection switch and a signal lamp;

(5) for the convenience of field maintenance, a field operation interface of the frequency converter switch cabinet can simultaneously display a bus voltage value of the frequency converter, a motor current, an output frequency of the frequency converter, a motor running direction, a given mode of a speed of the frequency converter and a current state of the frequency converter.

2. The causticized green liquor system frequency conversion regulation control method according to claim 1, wherein the motor field control box in the step (1) is provided with a rain hat.

3. The causticized green liquor system frequency conversion regulation control method according to claim 2, wherein cables of the motor field control box go in and out.

4. The control method for the frequency conversion regulation of the causticized green liquor system according to claim 3, wherein the shell material of the motor field control box is made of a stainless steel plate with the thickness not less than 1.5 mm.

5. The control method for the variable frequency regulation of the causticized green liquor system as recited in claim 4, wherein the specification of the motor field control box is 300mm × 200mm × 400 mm.

6. The causticized green liquor system frequency conversion regulation control method according to claim 1, wherein the specification of the switch cabinet in the step (4) is 600mm × 500mm × 1800 mm.

7. The causticized green liquor system frequency conversion regulation control method according to claim 6, wherein a cooling fan is installed in the switch cabinet.

8. The method for controlling the frequency conversion regulation of the causticized green liquor system according to claim 1, wherein the working environment temperature of the frequency converter in the step (5) is as follows: -10 ℃ to 40 ℃.

9. The method for controlling the frequency conversion regulation of a causticized green liquor system according to claim 8, wherein the rated input voltage of the frequency converter is 3 × 400V +/-10% and 50Hz +/-5%.

10. The causticized green liquor system frequency conversion regulation control method according to claim 9, wherein all circuit boards of the frequency converter are provided with a thickened anticorrosive coating.

[ technical field ] A method for producing a semiconductor device

The invention relates to the technical field of frequency conversion regulation, in particular to a control method of frequency conversion regulation of a causticized green liquor system.

[ background of the invention ]

The causticized green liquor conveying system is an important link of an alkali recovery plant, and #1 and # 2 alkali furnace green liquor is conveyed to a green liquor tank and then is conveyed to a digester by a causticized green liquor pump to react with quick lime to form primary white liquor for a pulping plant to use. The main components of the green liquor are sodium carbonate and sodium sulfide, the green liquor has the characteristics of high concentration and high viscosity, a conveying pipeline is easy to scale, and the scale formation is closely related to the conveying speed of the green liquor.

The raw green liquor system design capacity is as follows: the flow rate is 60-120 m³And h, the opening of the electric regulating valve is 0-100%, and the power of the motor is 22 KW/380V. The control mode adopts an electric regulating valve, the opening degree of the valve is difficult to regulate, the error is large, the precision is low, and the green liquor conveying pipeEasy scaling, difficult control of the liquid level of the green liquor tank and the like.

[ summary of the invention ]

The technical problem to be solved by the invention is to provide a control method for frequency conversion adjustment of a causticized green liquor system, so as to solve the problems of difficult adjustment of the opening degree of a valve, large error, low precision, easy scaling of a green liquor conveying pipeline, difficult control of the liquid level of a green liquor tank and the like.

In order to achieve the technical purpose, the design scheme of the invention is as follows:

a control method for frequency conversion adjustment of a causticized green liquor system comprises the following steps:

(1) centralized control: namely, the console is used for remote control;

(2) machine-side control: the motor is turned on or off on the motor field control box;

(3) the frequency conversion cabinet can input and output the following signals:

1) frequency conversion cabinet switching value input signal: the frequency converter is driven, namely a passive contact is closed to start, and the vehicle is cut off to stop;

2) frequency conversion cabinet speed given signal: 4-20 mADC, and giving a signal at a speed;

3) the frequency conversion cabinet at least outputs the following signals:

① running system, frequency conversion speed regulation device running signal;

② failure alarm, wherein the frequency conversion speed regulation control device stops the alarm signal of the main motor;

③, feeding back a motor rotating speed signal of 4-20 mADC;

④, feeding back current of 4-20 mADC and motor current signals;

4) step 1), all switching value contacts are passive contacts, the contact capacity is not less than 3A/220VAC, all analog values are 4-20 mADC signals, and a signal isolator is added in a variable-frequency speed-regulating switch cabinet;

(4) the front side of the variable frequency speed regulation switch cabinet is provided with a power frequency-variable frequency selection switch and a signal lamp;

(5) for the convenience of field maintenance, a field operation interface of the frequency converter switch cabinet can simultaneously display a bus voltage value of the frequency converter, a motor current, an output frequency of the frequency converter, a motor running direction, a given mode of a speed of the frequency converter and a current state of the frequency converter.

Further, the motor field control box in the step (1) is provided with a rain hat.

Further, the cables of the motor field control box enter and exit from the lower part.

Further, the shell material of the motor field control box is made of a stainless steel plate with the thickness not less than 1.5 mm.

Further, the specification of the motor field control box is 300mm × 200mm × 400 mm.

Further, the specification of the switch cabinet in the step (4) is 600mm × 500mm × 1800 mm.

Further, a heat radiation fan is installed in the switch cabinet.

Further, the working environment temperature of the frequency converter in the step (5): -10 ℃ to 40 ℃.

Furthermore, the rated input voltage of the frequency converter is 3 × 400V +/-10% and 50Hz +/-5%.

Furthermore, all circuit boards of the frequency converter are provided with thickening anti-corrosion coatings.

Through this technical scheme, can realize following effect:

(1) the causticized green liquor system is transformed by frequency conversion, the electric valve control mode of the original green liquor system is replaced by the stepless speed regulation of the frequency converter, and the problems of difficult adjustment of the opening degree of the valve, large error, low precision, easy scaling of a green liquor conveying pipeline, difficult control of the liquid level of a green liquor tank and the like are solved.

(2) The improved causticized green liquor system has the main functions as follows: the rotating speed of the green liquor pump is automatically/manually controlled, stepless automatic/manual adjustment is realized, and the adjusting speed is sensitive; the current is small and the starting torque is large during starting; the frequency converter implements the over-frequency function of the motor and the green liquor pump; optimizing the conveying speed of the green liquor, controlling scaling and ensuring the liquid level of the green liquor tank; energy saving is large and efficiency is high.

[ description of the drawings ]

FIG. 1 is a schematic control diagram of the frequency conversion regulation of the causticized green liquor system of the present invention.

[ detailed description ] embodiments

In order to facilitate a better understanding of the invention, the following examples are given to illustrate, but not to limit the scope of the invention.

As shown in fig. 1, a control method for frequency conversion adjustment of a causticized green liquor system comprises the following steps:

(1) centralized control: namely, the console is used for remote control;

(2) machine-side control: the motor is turned on or off on the motor field control box;

(3) the frequency conversion cabinet can input and output the following signals:

1) frequency conversion cabinet switching value input signal: the frequency converter is driven, namely a passive contact is closed to start, and the vehicle is cut off to stop;

2) frequency conversion cabinet speed given signal: 4-20 mADC, and giving a signal at a speed;

3) the frequency conversion cabinet at least outputs the following signals:

① running system, frequency conversion speed regulation device running signal;

② failure alarm, wherein the frequency conversion speed regulation control device stops the alarm signal of the main motor;

③, feeding back a motor rotating speed signal of 4-20 mADC;

④, feeding back current of 4-20 mADC and motor current signals;

4) step 1), all switching value contacts are passive contacts, the contact capacity is not less than 3A/220VAC, all analog values are 4-20 mADC signals, and a signal isolator is added in a variable-frequency speed-regulating switch cabinet;

(4) the front of the frequency conversion speed regulation switch cabinet is provided with a power frequency-frequency conversion selection switch and a signal lamp.

(5) For the convenience of field maintenance, a field operation interface of the frequency converter switch cabinet can simultaneously display a bus voltage value of the frequency converter, a motor current, an output frequency of the frequency converter, a motor running direction, a given mode of a speed of the frequency converter and a current state of the frequency converter.

The motor field control box in the step (1) is provided with a rain hat, a cable of the motor field control box enters and exits from the lower part, the shell of the motor field control box is made of a stainless steel plate with the thickness not less than 1.5mm, and the specification of the motor field control box is 300mm × 200mm × 400 mm.

The specification of the switch cabinet in the step (4) is 600mm × 500mm × 1800mm, and a heat radiation fan is installed in the switch cabinet.

In the step (5), the working environment temperature of the frequency converter is-10-40 ℃, the rated input voltage of the frequency converter is 3 × 400V +/-10%, 50Hz +/-5%, and all circuit boards of the frequency converter are provided with thickening anticorrosive coatings.

The present invention is illustrated by the following more specific examples.

Technical requirements of frequency converter

The frequency converter adopts international and domestic famous brands, is applied to mature series products in the industrial field, is provided with a helper-type control panel, has friendly interface and has a Chinese display function.

Basic data:

1. the temperature of the working environment: -10 ℃ to 40 ℃;

2. rated input voltage 3 × 400V + -10%, 50Hz + -5%;

3. the modulation method comprises the following steps: PWM pulse width modulation and U/f control;

4. setting frequency precision: ± 0.2% output frequency: 0.5-60 Hz;

5. overload capacity: 150% (60S), 200% (0.5S);

6. starting torque: 150% (from 0.5 Hz);

7. and (4) protective measures: earthing fault, overcurrent, overvoltage, undervoltage, overload and overtemperature of frequency converter I²tt monitoring, device overtemperature protection and the like;

8. analog output input signal: at least 2 of 4-20 mADCs respectively;

9. digital quantity output input signal: at least 6, with potential isolation and free programming;

10. outputting a signal: frequency converter failure, operation, etc.;

11. all circuit boards must be provided with a thickened corrosion resistant coating.

Second, technical requirements of the switch cabinet

1. The switch cabinet is controlled by frequency conversion and power frequency, and the frequency conversion constant voltage control receiver controls a PID to output a 4-20 mA signal to regulate frequency conversion;

2. protection grade of the switch cabinet: above IP 54;

3. the specification of the switch cabinet is 600 × 500 × 1800(W × D × H), the material is steel plate which is not less than 2mm, the switch cabinet is installed by wall, camel grey, and cables enter and exit from the lower part;

4. the distribution element should adopt ABB, Siemens and Schneider products;

5. a circuit breaker and a fast fuse must be installed between the frequency converter and the input power supply;

6. the connecting terminal is a Wendly Miller or a phoenix product;

7. the frequency converter is in signal connection with external connection and requires electrical isolation;

8. a heat radiation fan is arranged in the switch cabinet;

9. in order to reduce the interference to other equipment, reactors are required to be additionally arranged on the wire inlet side and the wire outlet side of the variable-frequency speed regulating device, and the reactors specified in a product sample of a frequency converter manufacturer are required to be adopted;

10. the motor field control box is provided with a rain-proof cap, IP54, a cable goes in and out from the lower part, a stainless steel plate with the material being not less than 1.5mm, and 300 × 200 × 400(W × D × H).

Third, control method (as shown in the figure)

1. Centralized control: namely, the console is used for remote control;

2. machine-side control: the motor is turned on or off on the motor field control box;

3. the frequency conversion cabinet can input and output the following signals:

3.1 input signal of the switching value of the frequency conversion cabinet: frequency converter drive (passive contact, closed start, open stop);

3.2 frequency conversion cabinet speed given signal: 4-20 mADC, and giving a signal at a speed;

3.3 signals that the frequency conversion cabinet should output at least:

3.3.1 System operation: running signals of a variable frequency speed regulating device;

3.3.2 Fault alarm: the frequency conversion speed regulation control device stops the alarm signal of the main motor;

3.3.3 speed feedback: 4-20 mADC, motor rotation speed signal;

3.3.4 Current feedback: 4-20 mADC, motor current signal;

all the switching value contacts above 3.4 are passive contacts, the contact capacity is not less than 3A/220VAC, and all the analog values are 4-20 mADC signals. A signal isolator is added in the variable-frequency speed-regulating switch cabinet;

4. the front of the variable frequency speed regulation switch cabinet is provided with a power frequency-variable frequency selection switch and necessary signal lamps;

5. for the convenience of field maintenance, a field operation interface of the frequency converter switch cabinet can simultaneously display a bus voltage value of the frequency converter, a motor current, an output frequency of the frequency converter, a motor running direction, a given mode (such as automatic/manual) of the speed of the frequency converter, a current state (ready/running/fault) of the frequency converter and the like.

Fourth, the analysis of the improved effect

1. Energy saving

It is known from hydrodynamics that P (power) is Q (flow rate) x H (pressure), the flow rate Q is proportional to the first power of the rotation speed N, the pressure H is proportional to the square of the rotation speed N, and the power P is proportional to the cube of the rotation speed N. Namely, the power consumption of the water pump motor and the rotating speed are approximately in a cubic ratio relation. Tests show that the power of a pump motor of the green liquor pump is 22KW, and the power consumption is 11.26KW when the rotating speed is reduced to 4/5 of the original rotating speed, namely 40HZ, and the electricity is saved by 48.8%.

2. Soft start

Because original motor starts for direct start, and the starting current equals 4 ~ 7 times rated current, the damage to baffle and valve during heavy current and the vibrations that produce during the start is big, and is unfavorable to the life of equipment, pipeline. After the frequency conversion energy-saving device is used, the starting current starts from zero by utilizing the soft starting function of the frequency converter, and the maximum value does not exceed the rated current, so that the service lives of equipment, valves and the like are greatly prolonged. The maintenance cost of the equipment is saved.

3. Automatic control

The green liquor pump is controlled by the frequency converter and the PID controller to realize stepless automation, the regulation speed is sensitive, the control precision is high, and the liquid level and flow control accuracy is high.

4. Overclocking

The conveying speed of the green liquor is optimized, scaling is controlled, and short-time high-pressure washing and scaling are carried out on the pipeline scaling by using a frequency converter over-frequency technology if necessary.

The above-mentioned embodiments are only preferred embodiments of the present invention, and do not limit the technical scope of the present invention, so that the changes and modifications made by the claims and the specification of the present invention should fall within the scope of the present invention.