KR100596034B1 - Apparatus for recovering the fly ash with high pure and fine size of coal-fired power station - Google Patents

Abstract

The present invention relates to a high purity and fine powder recovery ash recovery device of a thermal power plant having a low unburned carbon content and a high powder density by a centrifugation process using the particle size and specific gravity difference of each component in the powder, more specifically thermal power plant The present invention relates to a high-purity and fine coal ash recovery device that can be applied to a refining facility for easily separating unburned carbon and the like contained in coal ash generated from the back.

In the conventional coal ash separation process, most of the wet processes designed for use in a coal manufacturing plant have a problem in that coal purified by such a wet process has to be dehydrated and dried before being transported to a boiler and combusted. When the unburned carbon content is more than 9%, it is impossible to recover less than 3% of the unburned carbon content due to the occurrence of unburned carbon crushing as a granulated powder and a recovery rate at which coarse particles are removed.

The present invention uses the difference in particle size and specific gravity, which are inherent physical properties of coal ash and unburned carbon, to solve the above problems. If it is high, the opening angle is increased, and if the content of unburned carbon is low, the opening angle is improved to improve the removal rate of unburned carbon. The two-stage centrifugation and the fine particle suspension method which collect | recover were performed together.

A guide vane was installed to control the recovery rate and particle size during the unburned carbon centrifugation from coal ash, and the fine particle flotation induction device for recovering fine particles mixed in the removed granulated powder and the secondary air inlet for floating fine powder It is composed of high purity (less than 3% of unburned carbon content) and uniformly sized coal ash.

Description

Apparatus for recovering the fly ash with high pure and fine size of coal-fired power station

1 is an overall system diagram showing a high purity and coal ash recovery process of the thermal power plant to which the present invention is applied,

Figure 2 is a schematic top side view of the cyclone centrifugation unit that is the main part of the present invention,

3 is a side cross-sectional view of FIG. 2.

Explanation of symbols on the main parts of the drawing

1: hopper for storing coal ash, 2: hopper rotary feeder,

3: vibratory ash transport vibrator, 4: coal ash feed vibration plate,

5: blower for primary and secondary air propulsion, 6: nozzle for coal ash pressurization,

7: suction part, 8: propulsion air and suction powder mixing part,

9: guide plate type coal ash centrifugal separator, 10: guide plate,

11: guide plate opening angle adjuster, 12: fine powder floating induction device,

13: secondary air inlet for fine powder floating, 14: granulated powder collecting,

15: automatic load type double damper, 16: rotary feeder for discharging granulated powder,

17: upper fine powder outlet, 18: cyclone for collecting fine powder,

19: refinery discharge damper and rotary feeder,

20: upper discharge pipe, 21: bag filter,

22: clean air outlet, 24: round tube,

25: centrifuge, 26: funnel,

27: lower discharge pipe, 28: assembled powder collecting portion,

29: assembly powder collecting funnel, 30: assembly powder discharge pipe,

40: coal ash supply unit, 50: refinery ash recovery unit.

The present invention recovers high-purity and fine coal ash of a coal-fired power plant that easily separates unburned carbon, which is an impurity contained in coal ash generated from a coal-fired power plant, and granulated powders that drop powder, thereby recovering high-purity and fine-grain refined ash. Relates to a device.

Usually, coal ash generated after coal combustion during thermal power plant operation has high value as a concrete admixture, a building lightweight agent, and a fill agent. In general, however, coal ash generated from power plants contains a large amount (5-10%) of unburned carbon, which is an obstacle to recycling. Therefore, in order to use this for industrial purposes, the separation of unburned carbon in coal ash (3% or less) is essential.

Conventional unburned carbon separation methods include wet flotation and dry simple cyclone centrifugation.

The former wet method is economical due to the high cost of dehydration, drying and wastewater treatment. The latter dry centrifugation method is based on the fact that large particles of coal ash contain large amounts of unburned carbon. Although the air classifier is used, when the unburned carbon content in coal ash is more than 5%, the particle size classification is not complete, and it is converted into fine powder due to the crushing by the impact of the coarse and is discharged together with the coal ash fine powder. There is a disadvantage that can not recover the coal ash.

On the other hand, even if the raw carbon ash content of raw ash is low, there is a disadvantage that can not adjust the fine fraction recovery.

Accordingly, the present invention has been invented to solve the problems as described above, the secondary air to prevent the simultaneous removal of granulated powder and the ability to adjust the overall efficiency by adjusting the angle of the guide plate according to the coal ash content The purpose is to provide a high-purity and fine coal ash recovery apparatus of the thermal power plant that can be recovered by injecting the fine particles to increase the recovery rate of the fine particles.

The present invention for achieving the above object, unlike the existing cyclone is equipped with a guide plate (Guide Vane) at the inlet of the cyclone (Tangential of the flow rate inside the cyclone according to the opening angle even if the air injection amount is the same (Tangential) As the centrifugal force is changed due to the change of Velocity, the classification particle size is adjusted secondly. Also, the fine powder among the granulated powder descending to the side (outer wall) of the fine particle induction device is suspended by secondary air in the upper part of the cyclone. The fine powder suspension and the granulated powder recovery part were separately installed so as to discharge them.

Coal ash is quantitatively controlled by the coal ash storage hopper and the coal ash transport vibrator, and flows into the cyclone through the ejector according to the principle of venturi tube. The removal angle of granular powder is increased by reducing the opening angle of the guide plate, and when the unburned carbon content is 5% or less, the removal angle of the granular powder is decreased by increasing the opening angle of the guide plate. It is discharged through the cyclone upper discharge pipe and collected in the cyclone collector of the rear stage, and the uncollected ultrafine particles are completely removed by a bag filter and recovered together with the fine coal ash.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

Figure 1 shows the overall schematic diagram of the high purity and fine coal ash recovery device of the thermal power plant according to the present invention, a device for dry separation of unburned carbon contained in coal ash.

The present invention relates to a coal ash storage hopper (1), a coal ash conveying vibrator (3) and a diaphragm (4) for supplying coal ash by appropriate amounts by the vibrator (3) and a coal ash pressurization nozzle (6) based on the principle of a venturi tube. Suction part 7 in which coal ash and external air are sucked by negative pressure by the nozzle 6, and mixing part 8 in which coal ash and propulsion air sucked by the suction part 7 are mixed and frictionally charged. Coal ash supply unit 40 comprising an ejector composed of a) and a blower (5) for supplying air to the ejector;

The coal ash supplied by the coal ash supply unit 40 to the induction plate 10 for adjusting the separation recovery rate according to the unburned carbon content and the opening angle controller 11 for adjusting the opening angle of the induction plate 10 and the cyclone bottom. Secondary air is injected to float the fine powder contained in the fine powder floating induction device 12 which prevents the discharge of fine powder, and the fine powder contained in the granulated powder descending to the side (outer wall) of the fine particle floating induction device 12. The injection portion 13 and the granulated powder descending from the granulated powder collecting unit 14 are introduced through the automatic load type double damper 15 and the double damper 15 to prevent air leakage and lower the granulated powder. A granulated powder recovery and fine powder floating device 14 for centrifuging coal ash composed of a rotary feeder 16 for discharging the granulated powder;

The fine powder collected by the fine powder collecting cyclone 18 and the fine powder collecting cyclone 18 to collect the fine powder discharged through the upper fine powder outlet 17 in the guide plate centrifugal separator 9. After removing the fine particles collected in the discharge damper and rotary feeder 19 and the fine dust collecting cyclone 18 to recover the refinery ash to the upper discharge pipe 20 to remove them from the bag filter 21 to completely remove the clean air It consists of a purified ash recovery unit 50 as a component of the clean air outlet 22 for discharging.

2 is a top cross-sectional view of a cyclone centrifugal separator which is the core of the component of the present invention, and FIG. 3 is a cross-sectional view of the front of the cyclone centrifugal separator.

Here, the powder and the air mixture are configured to flow in the tangential direction of the cyclone rotating body, and the guide plate 10 is formed in a rectangular shape. And the opening angle adjuster 11 is installed at the top to adjust the opening angle of the guide plate 10.

In FIG. 3, an adjustment scale is indicated on the opening angle controller 11 of the guide plate 10 made of SUS304 material. In the present invention, by installing a cyclone made of SUS304 material to prevent the wear caused by the coal ash as much as possible, the size and recovery rate of the particles discharged to the upper fine particle outlet 17 of the cyclone portion according to the opening angle of the guide plate 10 is controlled. The opening angle adjuster 11 is provided so that it is possible.

Here, the guide plate 10 is a rectangular guide plate, which is provided with a funnel pipe 26 connected to a circular tube 24 and a centrifugal separator 25 on the outside thereof, and connected to the funnel pipe 26. The lower discharge pipe 27, the granulated powder collecting part 28, and the granulated powder collecting funnel 29 are provided.

In the induction plate-type cyclone apparatus of the present invention, the principle of centrifugation is to remove the unburned carbon distributed in the granulated powder to the bottom by using the centrifugal force difference according to the opening angle of the guide plate, and to recover the fine powder refinery to the top. On the other hand, a fine powder floating induction device 12 is installed to guide the suspended fine coal ash contained in the coarse ash coal ash removed to the bottom to be discharged to the upper side, and descend to the side of the fine powder floating induction device 12. The granulated powder is discharged through the direct assembly powder discharge pipe 30 and the fine powder is suspended by secondary air, characterized in that configured to be discharged through the upper fine powder discharge port (17).

Induction plate-type coal ash centrifugal separator (9), which is the main part of the present invention, was made of SUS304 material to reduce wear due to contact with powder, and the unburned carbon removal rate was controlled by using the opening angle of the induction plate (10). The fine particle recovery rate is configured to be adjusted by using a recovery rate control plate at an opening angle of 60 ° or more.

In addition, in order to improve the particle size classification efficiency (performance curve), the secondary air injector 13 for fine particle floating and the fine particle floating inducing device 12 are provided.

<Example>

Referring to the size of the guide plate centrifugal separator according to the present invention for treating the size of the embodiment as follows.

Equipment specifications of the cyclone electrostatic separator are as shown in Figs. 2 and 3, the cyclone diameter (Dc) 20cm, the discharge pipe diameter (De) 10cm, the height (Lc + Zc) 80cm, the upper outlet 17 Is located in the center of the cyclone and installed with De = Dc / 2, Lc = 2DC, and Sc = Dc / 4.

The guide plate 10 of FIG. 3 is provided with 12 SUS304 plates having a width of 4.3 cm, a height of 9.5 cm, and a thickness of 2 mm toward the discharge port 17 at 30 degrees to allow full opening and closing.

The size of the cyclone inlet was 5.0 cm in width (Bc) and 10 cm in length (Hc). In the case of granulated powder collection and fine powder floating induction part, the form and configuration of the cyclone in the specifications of Dt 10cm, Lc = 2Ls = 4Li, 4Dt = 5Di are shown in FIGS. 2 and 3.

Experimental conditions are as follows.

Experimental variable: cyclone guide plate opening angle

-Inflow air: 3 ~ 4㎥ / min

-Secondary air volume: 0.5 ~ 1㎥ / min

-Coal ash composition: 1 kind of coal ash with 9% unburned carbon content

-Capacity: 30Kg / hr

The fine ash refinery recovery was measured using the mass distribution collected in the refinery bag filter, and the unburned carbon content was measured using a thermal analyzer.

The analysis results of the test sample used for the experiment are shown in Table 1.

<Table 1> Mass distribution, cumulative distribution and unburned carbon content of coal ash samples by particle size

                                                        (Unit: wt.%)

Sample Type Particle Size Distribution [㎛] +150 150-105 105-75 75-53 53-38 38-26 -26 5% Mass distribution 2.6 2.9 3.8 5.6 6.2 8.0 70.9 Unburned carbon 67.01 36.95 26.2 12.5 4.75 3.2 1.9 9% Mass distribution 2.8 3.9 4.6 5.5 5.8 6.4 71 Unburned carbon 62.39 33.38 30.36 17.33 12.03 6.69 2.92

As shown in <Table 1>, the mass distribution of coal ash increased as the particulate content, and the unburned carbon content tended to decrease as the particle size was increased. The unburned carbon content of 5% coal ash showed 70.9% of mass distribution and 1.9% of unburned carbon content below 26㎛. That is, it can be expected that high-purity coal ash of 3% or less can be recovered even by centrifugation (particle size separation) at 26 μm or less.

On the other hand, as a result of centrifugal experiment of 9% coal ash of unburned carbon, reducing the opening angle of the induction plate reduced coal ash recovery and unburned carbon content of fine powder as shown in <Table 2>. That is, 67% of unburned carbon with 3% coal was recovered at the induction plate opening angle of 60˚. The smaller the opening angle of the guide plate is, the smaller the particle size classification is, which reduces the recovery rate but increases the purity. In addition, in the case of powder, the raw ash ash increased from 2400 m2 / g to 4,500 m2 / g in fine refined ash, which greatly improved the quality of coal ash.

<Table 2> Changes in centrifugation efficiency according to guide plate opening angle

                                                     (Unit: wt.%)

Sample feed, unburned carbon content Opening angle 30˚ 40˚ 50˚ 60˚ Recovery Unburned carbon Recovery Unburned carbon Recovery Unburned carbon Recovery Unburned carbon 9% A closing society 45 40 46 28 Refinery 55 2.6 60 2.8 63 2.9 67 3.0

As described above, the high purity and fine coal ash recovery apparatus of the thermal power plant according to the present invention can improve the filling rate of concrete when recycled, that is, when used as a mixed concrete admixture because the particle size of the refinery ash is fairly uniform.

Claims (2)

Coal ash storage hopper (1), vibratory ash transport vibrator (3) and diaphragm (4) for supplying coal ash in an appropriate amount by the vibrator (3), coal ash pressurized nozzle (6) and pressurized nozzle (6) based on the venturi tube principle. A suction part (7) where coal ash and external air are sucked by negative pressure by a negative pressure) and a mixing part (8) where coal ash and propulsion air sucked by the suction part (7) are mixed and frictionally charged. A coal ash supply unit 40 having an ejector to be used and a blower 5 for supplying air to the ejector; The coal ash supplied by the coal ash supply unit 40 to the induction plate 10 for adjusting the separation recovery rate according to the unburned carbon content and the opening angle controller 11 for adjusting the opening angle of the induction plate 10 and the cyclone bottom. Secondary air is injected in order to float the fine powder contained in the fine powder floating induction apparatus 12 which prevents discharge of fine powder, and the granulated powder contained in the granulated powder falling to the side surface (outer wall) of the fine particle floating induction apparatus 12. The injection portion 13 and the granulated powder descending from the granulated powder collecting unit 14 are introduced through the automatic load type double damper 15 and the double damper 15 to prevent air leakage and lower the granulated powder. A granulated powder recovery and fine powder floating device 14 for centrifuging coal ash composed of a rotary feeder 16 for discharging the granulated powder; The fine powder collected by the fine powder collecting cyclone 18 and the fine powder collecting cyclone 18 to collect the fine powder discharged through the upper fine powder outlet 17 in the guide plate centrifugal separator 9. After removing the fine particles collected in the discharge damper and rotary feeder 19 and the fine dust collecting cyclone 18 to recover the refinery ash to the upper discharge pipe 20 to remove them from the bag filter 21 to completely remove the clean air High purity and fine coal ash recovery device of the thermal power plant, characterized in that consisting of a refinery ash recovery unit 50 as a component of the clean air outlet 22 for discharging. 2. The cyclone guide plate 10 is provided with an opening angle adjuster 11 for adjusting the opening angle of the guide plate 10 for adjusting the recovery rate of coal ash. High purity and fine ash recovery device of thermal power plant characterized by consisting of SUS304 material to prevent wear.

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