RU2232059C1 - Device for automatic control of an electrostatic precipitator - Google Patents

Abstract

FIELD: power engineering industry; thermoelectric power stations.

SUBSTANCE: the invention presents a device for automatic control of an electrostatic precipitator, that is dealt with the field of power engineering industry and may be used in the thermal power stations. In the device for automatic control of the electrostatic precipitator through two tubes, injected into an uprising part of section of a transport pipeline they realize an air supply for dust transportation and measurement of height (thickness) of its layer in the inclined and vertical parts of the section. The length of the uprising part is chosen smaller than the length of the vertical part, on the upper end of which there is a water resistance installed. For measurement of height of the dust layer in the section the device has a pressure sensor, a multiplier, a divider, a memory cell. The pressure regulator in the pipeline of an air supply allows to realize automatic control of dust passing through the transportation pipe-line depending on its passing the bin. The invention ensures reliability of operation of the electrostatic precipitator.

EFFECT: the invention ensures reliability of operation of the electrostatic precipitator.

1 dwg

Description

The invention relates to power engineering and can be used in electrostatic precipitators of thermal power plants.

A device for automatically controlling an electrostatic precipitator, comprising a hopper, actuating mechanisms for shaking the electrodes connected to a level gauge, a control unit, a gate feeder [1].

The disadvantage of this device is the inability to remove dust from the hopper at a considerable distance, the complexity of the design, determined by the presence of two level gauges.

The closest in technical essence to the considered solution is a device for automatic control of an electrostatic precipitator, containing a hopper, actuating mechanisms for shaking the electrodes connected to a level gauge, a transport pipeline consisting of sections in each with upward and inclined sections, air supply and exhaust units, respectively, in the lower and the upper parts of the ascending section, an air supply pipe connected to an overpressure source through a valve with an actuator connected to the outlet at the transmitter [2].

The disadvantage of this device is the inability to automatically control the process of removing dust from the hopper when changing the operating mode of the boiler, which determines a decrease in reliability.

SUMMARY OF THE INVENTION

A device for automatically controlling an electrostatic precipitator, comprising a hopper, actuating mechanisms for shaking electrodes connected to a level gauge, a transport pipeline consisting of sections in each with ascending and inclined sections, air supply and exhaust nodes respectively in the lower and upper parts of the ascending section, an air supply pipeline, connected to a source of excess pressure through a valve with an actuator connected to the output of the level gauge, two tubes, a pressure sensor, a multiplier, a divider, a memory element , a pressure regulator in the air supply pipe, constant hydraulic resistances, a pressure difference meter, wherein the air exhaust unit is made in the form of a vertical pipe, the lower end of which is connected to the upper part of the ascending section, and the hydraulic resistance is installed at the upper end, the length of the ascending section is chosen to be shorter vertical pipe, in the lower and middle parts of the ascending section of the first section there are output ends of two tubes, the input ends of which are connected to a source of excess the pressure, the inputs of the differential pressure meter are in communication with the tube cavities between the constant hydraulic resistance and the output end, the cavity of the upper tube between the constant hydraulic resistance and the output end is connected to a pressure sensor, the output of which is connected to the first input of the multiplier, the second input connected to the output of the memory element, and output - with the first input of the divider, the second input of which is connected to the output of the differential pressure meter, the output of the divider is connected to the air pressure regulator.

A device for automatic control of an electrostatic precipitator is shown in the drawing and contains a hopper 1, actuators 2 for shaking the electrodes connected to a level gauge 3, a transport pipeline, consisting of sections in each with ascending 4 and inclined 5 sections, supply nodes 6 and air exhaust 7, respectively, in the lower and the upper parts of the ascending section, the air supply pipe 8 connected to an overpressure source 9 through a valve 10 with an actuator. In the lower and middle parts of the ascending section 4 of the first section, the output ends of the tubes 11, 12 are located, the input ends of which are connected to a source of overpressure 9. The cavity of the tubes 11,12 between the constant hydraulic resistance 13, 14 and the output ends are connected to the inputs of the differential pressure gauge 15 . The cavity of the tube 12, located in the middle part of the ascending section, between its output end and constant hydraulic resistance is connected to a pressure sensor 16, the output of which is connected to the first input of the multiplier 17, the second input connected to the output of the memory element 18, and the output to the first input of the divider 19, the second input of which is connected to the output of the pressure difference meter 15, the output of the divider is connected to the air pressure regulator 20. The air exhaust unit is made in the form of a vertical pipe 21, the lower end of which is connected to the upper part of the ascending section, and a hydraulic resistance 22 is installed at the upper end.

The operation of the device is as follows.

As a result of the actuation of the level gauge transducer 3, the process of shaking the electrodes through the actuators 2 begins, dust enters the lower cavity of the hopper 1. Valve 10 opens, air enters the lower parts of the ascending sections of the sections of the transport pipeline, and also through the tubes 11, 12 to the first section, where sparges through the dust layer, and the parameters of the air flow in the tubes 11, 12 will be determined by the height of the dust layer in the upstream section and in the pipe 21. The height of the dust in the pipe 21 depends on its flow through the hopper and scab air in the tubes 11, 12. The equation of the mass balance in the channels with local expiration air of the two tubes has the form

P ₁ = ρ _t g (1-ε) H ₁ + P ₀ ;

P ₂ = ρ _t g (1-ε) H ₂ + P ₀ ,

where P ₁ and P ₂ - pressure in the cavities at the output ends of the tubes (bar);

ρ _t is the density of the particle material (g / cm ³ );

g is the acceleration of gravity (cm / s ² );

ε is the porosity (fraction of voids) of the dust layer;

H ₁ and H ₂ - the height of the output ends of the tubes (cm) from the dust level;

P ₀ - pressure above the dust layer.

After solving these equations together, we get

when H ₂ = H ₁ + l; and P ₀ = P _a (atmospheric pressure) we obtain the expression for determining the level of dust in the pipe 21:

From this expression, it is possible to determine the dust flow through the hopper and, depending on its size, regulate the productivity (flow) of dust through sections of the transport pipeline. The value of this flow rate depends on the air velocity in the nodes of its supply to the lower parts of the ascending section:

Q = (1-ε) ρ _t

where U is the velocity of the outflow of particles (U≈U _in - the speed of air);

S is the effective section of the pipeline.

Therefore, when receiving express information about the level in the pipe 21, it is possible to automatically adjust the performance of the transport pipeline and increase the reliability of the process of removing dust from the hopper.

Measuring the pressure value P _{1 by the} sensor 16 in the multiplier 17, we obtain the value l · P ₁ using a constant coefficient proportional to the distance between the output ends of the tubes 11, 12.

As a result of the conversion in the divider 19 of the output signals of the multiplier 17 and the pressure difference meter 15, we obtain a value corresponding to the height of the dust layer in the pipe 21, which does not depend on its physical parameters. According to the obtained value, the air flow rate is adjusted by the regulator 20.

According to experimental data, the critical height of the separation space — the height of the vertical section at which the particles are separated with a minimum size — corresponds to the length of the inclined section. Therefore, to exclude emissions of particles of a fine dust fraction into the atmosphere, the length of the vertical pipe 21 is chosen to be greater than the length of the inclined section. Installation at the upper end of the vertical pipe 21 of hydraulic resistance allows to reduce the air velocity in its separation space, which also determines the reduction of emissions into the atmosphere.

Thus, due to the introduction of two additional tubes that simultaneously implement two tasks of measuring the level of dust entering the transport pipeline and its pneumatic transport along the inclined section of the first section, an increase in the reliability of the electrostatic precipitator is achieved.

Sources of information

1. USSR author's certificate No. 1588440, B 03 S 3/68, 1987

2. RF patent No. 2192928, B 03 C 3/68, 2002

Claims (1)

A device for automatically controlling an electrostatic precipitator, comprising a hopper, actuating mechanisms for shaking electrodes connected to a level gauge, a transport pipeline consisting of sections in each with ascending and inclined sections, air supply and exhaust nodes, respectively, in the lower and upper parts of the ascending section, the air supply pipe, connected to a source of excess pressure through a valve with an actuator connected to the output of the level gauge, characterized in that two tubes are introduced into it, a pressure sensor I, a multiplier, a divider, a memory element, a pressure regulator in the air supply pipe, constant hydraulic resistance, a differential pressure meter, and the air exhaust unit is made in the form of a vertical pipe, the lower end of which is connected to the upper part of the ascending section, and a hydraulic one is installed on the upper end resistance, the length of the ascending section is chosen to be less than the length of the vertical pipe, in the lower and middle parts of the ascending section of the first section there are the output ends of two tubes, the input ends of which They are connected to a source of overpressure, the inputs of the differential pressure meter are in communication with the tube cavities between the constant hydraulic resistance and the output end, the cavity of the upper tube between the constant hydraulic resistance and the output end is connected to a pressure sensor, the output of which is connected to the first input of the multiplier, the second input connected to the output of the memory element, and the output with the first input of the divider, the second input of which is connected to the output of the differential pressure meter, the output of the divider is connected to Knob air pressure.