RU2330726C1 - Electric filter with wave section electrodes - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: electric filter consists of a casing, shaking mechanisms, wave-section precipitation elements and needle-type corona-forming elements. The wave-section precipitation elements have their adjacent sides arranged at the angle α varying from 30° to 120° and with the spacing equal to that the wave span of precipitation elements. The needle-type corona-forming elements have the planes arranged parallel to a flat part of precipitation elements. Distance (B) of the corona-forming elements flat part from that of the precipitation elements makes B=R/(1.1...2.3), where R is the distance from the corona-forming element end to the precipitation element rounded-off part.

EFFECT: high reduction of dust outburst from the electric filter.

2 dwg

Description

The invention relates to apparatuses designed to remove solid and liquid particles from gases using electrostatic precipitators, and can be used in power engineering, metallurgy, petrochemical and other industries.

Known electrostatic precipitators (analogs) such as UG, EGA, etc., equipped with C-shaped electrodes [1, 2], which are actually flat plates located parallel to the cleaned gas stream. To give stiffness when dusting off the elements, a “profile” is given, the height of which protrudes from the center line by 17 ... 20 mm. In addition, electrostatic precipitators are known [3, 4], equipped with smooth deposition electrodes.

The disadvantage of the precipitation electrodes in these electrostatic precipitators is the relatively low degree of gas purification due to the poorly developed deposition area. In addition, in these electrostatic precipitators there is a high uneven distribution of the corona current during the capture of high resistance dust.

The prototypes of the invention are electric aerosol coagulator A.S. No. 887469 and A.S. electrostatic precipitator SU 1643092 A1.

In these electrostatic precipitators, the precipitation electrodes have a deep wave profile. However, the gas flow does not follow along the bends of the precipitation electrode and the residence time of the gases in the electrostatic precipitator does not increase, which does not allow to obtain an additional effect on dust collection.

The proposed electrostatic precipitating electrode with a wave profile is devoid of these disadvantages. The difference of the proposed electrostatic precipitator is that the corona elements are provided with planes parallel to the flat part of the precipitation elements, while the angle formed by the adjacent sides of the profile of the precipitation elements is 30 ... 120 °, and the distance (B) of the flat part of the corona elements is from the flat part of the precipitation elements is B = R / (1.1 ... 2.3), where R is the distance of the needles of the corona elements from the rounded part of the precipitation electrodes.

Figure 1 shows a cross section of an electrostatic precipitator. Figure 2 - active zone of the electrostatic precipitator. The list of positions in the figures:

1 - electrostatic filter housing;

2 - precipitating element;

3 - corona element;

4 - shaking devices for sedimentary and corona elements (conditionally);

5 - flat part of the precipitating element;

6 - rounded part of the precipitating element;

7 - the needle of the corona element;

8 is a flat part of the corona element.

α is the angle between the flat adjacent sides of the profile of the precipitation electrode.

Precipitation element (2) is a combination of flat (5) and rounded (6) parts. In the center of the rounded parts are the ends of the needles (7) of the corona elements (3). To increase the intensity of the electrostatic field, the housing of the corona elements has a flat part and is made, for example, in a box shape. The angle α formed by the flat adjacent sides of the profile of the precipitation elements is shown in the drawing equal to 90 °. Depending on the required degree of gas purification, the angle α can vary in the range of 120 ... 30 °. At an angle greater than 120 °, an increase in the field length and the degree of gas purification will be insignificant. With a decrease in the angle α less than 30 °, a sharp increase in the hydraulic resistance of the electrostatic precipitator will occur, therefore, a further decrease in the value of the angle is impractical.

The functioning of the proposed electrostatic precipitator is as follows: dusty gas enters the interelectrode gap (Fig. 1) and, thanks to the directing action of the flat parts of the corona elements (3), moves in the interelectrode gap, making turns in accordance with the direction of the interelectrode gaps. In this case, the flow path increases. So, for example, if the angle α between adjacent flat sides of the profile of the precipitation elements is 90 °, then the calculated flow path increases by 1.41 times (when the angle α changes from 120 to 30 °, the calculated flow path changes from 1.23 to 4 , 34 times). This increases the degree of gas purification, as it increases the residence time of dust particles in the active zone of the electrostatic precipitator.

Calculations show that, for example, when the angle α = 90 °, dust emissions are reduced by 3.5 ... 6.0 times compared with the analogue and prototype. (3.5 times - with the degree of purification of the prototype 98% and 6 times with the degree of purification of the prototype 99.88%). Moreover, the degree of purification of the proposed electrostatic precipitator is 99.49% and 99.98%, respectively.

The most important parameter of the proposed electrostatic precipitator is to ensure electrical equal strength (equality of breakdown voltage) between: 1 - the ends of the corona needles and the rounded part of the precipitation electrode and 2 - the flat parts of the corona and precipitation electrodes. This condition of equal strength is provided depending on the technological conditions of operation of the electrostatic precipitator as follows:

- when capturing low resistance dusts and at low concentrations of dust, in particular in the last fields of the electrostatic precipitator, the value B = R · k,

where B is the distance between the flat parts of the corona and precipitation electrodes;

R is the distance from the ends of the needles of the corona elements to the rounded part of the precipitation elements;

K - coefficient equal to 1.1 ... 1.3.

With high-resistance dusts and dusts having a high concentration, in particular, in the first fields of electrostatic precipitators, the value k = 1.9 ... 2.3.

When capturing dusts having an intermediate value

specific electrical resistance (10 ⁸ ... 10 ⁹ Ohm / m), the value of the coefficient k = 1.3 ... 1.9.

In addition to increasing the degree of gas purification due to an increase in the residence time of gases in the electrostatic precipitator, there is an increase in the degree of purification due to the improved current distribution:

- in the zone of the crown - due to the equal distance of the corona needles from the precipitating surface (the rounded part of the element);

- in the area of the electrostatic field - due to increased tension. In this zone, due to the absence of corona current, the reverse corona is absent, which contributes to the efficient capture of high-resistance dust.

The manufacture of precipitation and corona electrodes according to the invention does not cause fundamental difficulties, since this can be used known methods of rolling sheet materials.

Literature

1. Chekalov L.V. (Edited) Ecotechnics. Yaroslavl “Russia”, 2004, p. 195, 196.

2. Uzhov V.N. Industrial gas purification by electrostatic precipitators. "Chemistry", Moscow, 1967, p. 121.

3. Patent JP 2001009305, IPC B03C 3/41, etc. 2001-01-16.

4. Patent JP 11156236, IPC B03C 3/08, etc. 1999-06-15.

5. Copyright certificate of the USSR SU 1643092 A1.

6. USSR copyright certificate SU 887469.

Claims (1)

An electrostatic precipitator consisting of a housing, shaking mechanisms, precipitation elements of the wave profile and needle-shaped corona elements, the step of the corona elements being equal to the step of the wave profile of the precipitation elements, characterized in that the corona elements are provided with planes parallel to the flat part of the precipitation elements, the angle being formed flat adjacent sides of the profile, precipitation elements is 30-120 °, and the distance (B) of the flat part of the corona elements from the flat part will precipitate of solid elements is B = R / (1.1 ... 2.3), where R is the distance of the needles of the corona elements from the rounded part of the precipitation elements.

Images