JP2016049475A - Unburned carbon recovery method and flotation separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate and recover froth containing high-concentration of unburned carbon from fly ash.SOLUTION: A flotation separator comprises: a treatment tank 1 into which a liquid to be treated prepared by slurrying unburned carbon-containing coal ash and water by stirring means is charged; froth discrimination means 22 for discriminating the content of unburned carbon in overflowing froth in the flotation separator where air bubbles are injected into the liquid to be treated to generate a swirl flow in the treatment tank 1 and froth is overflowed from a froth overflow port 2a installed in an upper part of the treatment tank 1; discrimination and recovery means that discriminates the froth into V froth having high content of the unburned carbon and P froth having low content of the unburned carbon according to the content of the unburned carbon discriminated by the froth discrimination means 22 and recovering them respectively in a V froth recovery tank 12 and a P froth recovery tank 11; and returning means 16 that returns the whole or a part of the recovered P froth to the treatment tank 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an unburned carbon recovery method and a floating separation device, and more particularly, to a method and an apparatus capable of separating and collecting floss containing unburned carbon from fly ash.

  Conventionally, a liquid to be treated in which fly ash is dispersed in water is stored in a treatment tank, a vortex is generated in the liquid to be treated, tail ash with a small amount of unburned carbon is recovered from the lower part, and a floss provided in the upper part is provided. There is a floating separation device that overflows and separates a floss containing a relatively large amount of unburned carbon from an overflow port (see, for example, Patent Document 1).

Patent No. 4802305

  As described above, the conventional technology separates fly ash into tail ash and floss, and tail ash obtained by a conventional apparatus is used for a concrete admixture or the like. The fly ash containing a large amount of unburned carbon was disposed of without being collected. In order to use it as an industrial product without discarding the floss, it is necessary to make the unburned carbon of the floss stable at a high content (for example, 50% or more). Improve the technology of the separation device.

  The present invention has been made in view of such problems. An unburned carbon recovery method and a floating separation device that increase the amount of unburned carbon recovered from floss separated from fly ash and reduce the generation of new waste. The purpose is to provide.

The gist of the present invention is a separation step of separating the unburned carbon by flotation in a first treatment tank of a liquid to be treated which is a slurry obtained by dispersing coal ash containing unburned carbon in water in a stirring tank. A measuring step for measuring the floss obtained by the flotation,
Based on the measurement result in the measurement step, the floss is discriminated and recovered by discriminating and recovering the V floss with a high content of unburned carbon and the P floss with a low content of unburned carbon. The P froth is re-introduced into the liquid to be treated in the first treatment tank, and the step of flotation is performed again.

    In addition, in the second stirrer tank different from the stirrer tank, the V froth is treated as a liquid to be treated and the flotation is performed in the second treatment tank, and unburned carbon is recovered as C froth having a high content of 80% or more. A recovery method and apparatus comprising a process.

  According to the present invention, froth containing unburned carbon can be separated and recovered from fly ash, the content of unburned carbon is improved and stabilized, the generation of new waste is reduced, the effective use of resources and the environment It can contribute to conservation.

It is a system configuration figure showing an embodiment of a floating separation device by the present invention. It is explanatory drawing which shows embodiment of the floss discrimination | determination means provided with the direction switching valve. (A) is a graph showing the relationship between loss of ignition and floss collection time, (b) and (c) are luminance, and (d) is color intensity on the horizontal axis. (A) is a graph showing ignition loss of tail ash, and (b) is a graph showing ignition loss of V floss for the conventional apparatus and the apparatus according to the present invention. It is the graph which showed the relationship between C froth collection | recovery time and ignition loss at the time of processing V floss using the apparatus of FIG. It is a photograph explaining the ratio of color intensity. It is a system block diagram which shows other embodiment of the floating separation apparatus by this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a system configuration diagram showing an embodiment of the floating separation apparatus of the present invention.

    The floating separation apparatus shown in FIG. 1 has a cylindrical processing tank 1, and a frusto-collecting tray 2 having a truncated cone shape is provided in the upper part of the processing tank 1. A floss overflow port 2 a is provided at the upper end of the floss collection tray 2.

  A slurry charging channel 3 and a pine oil charging channel 4 are connected to the upper part of the floss overflow port 2a, and a floss recovery channel 5 is connected to the vicinity of the lower end of the floss recovery tray 2. A circulation channel 6 is connected between the upper part and the lower part of the treatment tank 1. The upper end of the circulation channel 6 is located at the upper part of the processing tank 1 (below the froth collection tray 2) and below the surface of the liquid to be treated in the processing tank 1, and the lower end of the circulation channel 6 is treated. Located in the lower part of the tank 1. A pump 7 and a microbubble generator 8 are provided in the middle of the circulation flow path 6. Pine oil is a kind of foaming agent.

  A direction switching valve 10 is provided in the floss recovery flow path 5, and a P floss recovery flow path 12 that leads from the direction switching valve 10 to the P floss recovery tank 11 and a V floss recovery flow path 14 that leads to the V floss recovery tank 13 branch off. Has been. A P-floss reflux channel 16 is connected from the P-floss recovery tank 11 to the stirring vessel 15, and a pump 17 is provided in the P-floss reflux channel 16. The slurry charging flow path 3 is connected to the lower end of the stirring tank 15, and a pump 18 is provided in the middle thereof.

  A raw material containing unburned carbon (for example, fly ash), water, and a scavenger (for example, kerosene) is introduced into the stirring tank 15 from above, and the stirring bar 19 is rotated through the rotating shaft 21 to form a slurry. The liquid to be treated is obtained, and this is introduced into the treatment tank 1 from the floss overflow port 2a through the slurry introduction channel 3 by the pump 18. The raw material, water, and collecting material may be input in any order. Note that pine oil is introduced after water is introduced.

  The liquid to be processed falls and is stored in the processing tank 1, and the stored liquid to be processed is forcibly circulated through the circulation channel 6. Microbubbles are mixed in the microbubble generator in the middle of the circulation channel 6 and flow along the inner surface of the processing tank 1 to form a vortex in the processing tank 1. It overflows from the floss overflow port 2 a and falls along the floss collection tray 2.

A tail ash collection channel 36 is provided at the lower end of the treatment tank 1, and the tail ash T from which most unburned carbon has been removed from the tail ash collection channel 36 falls into the tail ash collection tank 37. Collected.

  The floss F overflowed from the floss overflow port is measured by the floss discrimination means 22, and the measured data is converted into a direction switching signal by the floss discrimination means 22. The floss discrimination means 22 transmits the direction switching signal to the direction switching valve 10, and the direction switching valve 10 is controlled based on the direction switching signal. The floss discrimination means 22 will be described later.

  The fallen Floss F is recovered from the Floss recovery flow path 5 and sent to the direction switching valve 10. The direction switching valve 10 is controlled by a direction switching signal from the floss discriminating means 22 and is distributed to either the P floss recovery flow path 12 or the V floss recovery flow path 14, and the P floss FP is transferred to the P floss recovery tank 11. The floss FV is recovered in the V floss recovery tank 13.

  Here, V floss is a component having a high content of unburned carbon in floss F (unburned carbon is 50% or more), and P floss is a low content of unburned carbon less than that ( It is defined as a component having an unburned carbon content of less than 50%. Part or all of the P froth FP collected in the P froth collection tank 11 is returned to the stirring tank 15 from the P froth reflux channel 16 and is again stirred with the raw material to repeat the above flotation.

FIGS. 2A to 2D show specific examples of the floss discrimination means 22 and the direction switching valve.
FIG. 2A shows an example in which the floss discrimination means 22 is composed of a timer 23. That is, the time after the floss F starts to overflow is measured by the timer 23, and the direction switching valve 10 is switched based on the time measured by the timer 23.

FIG. 3A shows the results of testing the relationship between the collection time and the loss on ignition for two types of froth, A ash and B ash.
It can be seen that in both A ash and B ash, the loss on ignition decreased to less than 50% almost 10 minutes after the floss began to overflow. Accordingly, in FIG. 2 (a), by switching the direction switching valve 10 to the V floss recovery flow path 14 side when it is less than 10 minutes after the floss F starts to overflow, to the P floss recovery flow path 12 side when it is 10 minutes or longer. The P-floss FP and the V-floss FV can be discriminated and recovered in the P-floss collection tank 11 and the V-floss collection tank 12, respectively.

  FIG. 2B shows the intensity of the reflected light from the light source 26 of the overflow Floss F, for example, the brightness of the surface of the Floss F is measured, and the valve 30 or 31 is controlled to be opened based on this measurement data. It is. That is, a floss measuring tank 25 is provided in the middle of the floss collecting flow path 5, and the floss F collected in the floss measuring tank 25 is irradiated from a distance of 300 mm with a light source 26 (halogen lamp, illuminance 3500 lx). Consists of a luminance meter and measures luminance. The control unit 28 determines whether the luminance measured as the intensity of the reflected light is greater than or equal to the set value and controls to open either the solenoid valve 30 or the solenoid valve 31, whereby P floss and V Floss can be determined.

Illuminance can also be used as the intensity of reflected light. In that case, the photometer 27 is composed of an illuminometer, measures the illuminance, and controls to open the valve 30 or 31 based on the measurement data.

FIGS. 3B and 3C show the results of testing the relationship between the brightness of floss (common logarithm) and ignition loss for two types of floss (A ash and B ash). As is clear from the figure, the luminance and ignition loss are correlated for both A ash and B ash, and the common logarithm Log10 (Cd / m2) of luminance for both A and B ash is about 2.6. The ignition loss is reduced to less than 50%.

Here, the numerical value of the common logarithm Log10 (Cd / m2) of 2.6 is an example in the case where a halogen lamp and illuminance of 3500 lx are used as the light source 26. It is necessary to obtain a relationship with ignition loss by a test and set the common logarithm of luminance corresponding to the desired ignition loss as a set value.

FIG. 2 (c) shows that the floss F immediately after overflowing from the floss overflow port 2a is irradiated from a distance of 300 mm with a light source 33 (halogen lamp, illuminance 3500 lx), and a camera 32 (digital camera, open aperture value F3.3, (ISO sensitivity 2400, shutter speed 1/10 seconds), the reflectance of the floss F is measured, the measurement data is judged by the control unit 34, and the direction switching valve 10 is controlled based on this measurement data.

FIG. 3 (d) shows the Floss F measured with a camera 32 (digital camera, open aperture value F3.3, ISO sensitivity 2400, shutter speed 1/10 seconds) irradiated with a light source 33 (halogen lamp, illuminance 3500 lx). The result of testing the relationship between the ratio of color intensity (see FIG. 6) and loss on ignition is shown. As apparent from FIG. 3 (d), the red R, green G, and blue B all have a loss on ignition of less than 50% when the color intensity ratio is approximately 0.3. Therefore, in FIG. 2 (c), the control unit 34 determines whether the ratio of the color intensity is greater than or equal to the set value and switches the direction switching valve 10 to the V floss F side or the P floss F side. P floss and V floss can be discriminated.

FIG. 6 is a diagram (photograph) for explaining the intensity ratio of the color of the floss F. FIG. In FIG. 6, Floss F immediately after overflowing from the floss overflow port 2a is irradiated with a light source (not shown), and within 100 pixels square of RGB data (0 to 255) obtained from the camera (not shown). The ratio of the average values (the ratio in which the white W sample is 1 and the black B sample is 0) is the color intensity ratio.

FIG. 2 (d) shows an example in which a cylindrical floss reservoir 2b is provided in the floss overflow port 2, and the floss F 'immediately after collecting in the floss reservoir 2b is measured and recovered. That is, the floss F ′ is recovered from the floss reservoir 2b via the two floss recovery passages 12 and 14, and the electromagnetic valves 30 and 31 are provided in the respective floss recovery passages 12 and 14, respectively. The reflected light from the floss F ′ is measured by the luminance meter 27 (or camera) after being irradiated with the light source, and any one of the solenoid valves 30 or 31 is opened based on this measurement data. . Note that the means for collecting the floss F ′ in the floss reservoir 2b in this way can also be applied to the means for measuring the overflow time with a timer shown in FIG.
In addition, as shown in FIGS. 2A to 2D, in the determination using the reflection of light, it is necessary to prevent the light other than the light source from entering and to avoid the influence of disturbance light.

FIG. 4 (a) is a graph comparing the quality of tail ash ignition loss obtained by a conventional general floating separation apparatus and the method and apparatus of the present invention. As shown in the figure, the average of the conventional apparatus is about 1.4%, and in the present invention it is about 1.5%, and the input of P-floss does not affect the ignition loss of the collected tail ash. Recognize.

FIG. 4 (b) shows ignition loss of V froth obtained when the reprocessing of P froth collected by the method and apparatus of the present invention is not performed and when the reprocessing of P floss is performed. It is the graph which compared the quality of.

As shown in FIG. 4 (b), the V floss obtained when the reprocessing of P floss is not performed in the device of the present invention and the V floss obtained by the method and device of the present invention are the second time, the third time, It turns out that it is the ignition loss of about the same level in the 4th time. This means that it is possible to reduce the P-floss that has conventionally been treated as waste, and to increase the V-floss that can be used as an industrial product.

As described above, the ignition loss of V froth collected in the V froth recovery tank 13 is 50% or more, and this value is an experiment that is almost constant regardless of the ignition loss of fly ash as a raw material. It was confirmed by. When the calorific value of V floss is estimated from this ignition loss, it is 19.7 MJ / kg. Such V floss can be used as auxiliary fuel, pencil lead, recycled fuel, and the like.

FIG. 5 shows the content of a component with a loss on ignition of 80% or more by flotation using the floss obtained as described above as a raw material for 1 to 15 minutes using the floating separation apparatus shown in FIG. It is a figure which shows that C floss can be isolate | separated.

FIG. 7 shows a floating separation device for flotation of V-floss and recovering C-floss containing a component with an ignition loss of 80% or more.

The floating separation apparatus shown in FIG. 7 includes a cylindrical processing tank 10A, and a frusto-collecting tray 20A having a truncated cone shape is provided in an upper part of the processing tank 10A. A floss overflow port 20a is provided at the upper end of the floss collection tray 20A.

A slurry charging channel 30 and a pine oil charging channel 40 are connected to the upper part of the floss overflow port 20a, and a floss recovery channel 50 is connected near the lower end of the floss recovery tray 20A. A circulation channel 60 is connected between the upper and lower portions of the treatment tank 10A. The upper end of the circulation channel 60 is the upper part of the treatment tank 10A (below the froth collection tray 20A) and is located below the liquid surface to be treated in the treatment tank 10A. It is located in the lower part of the tank 10A. A pump 70 and a microbubble generator 80 are provided in the middle of the circulation channel 60.

A direction switching valve 100 is provided in the floss recovery flow path 50, and a P froth recovery flow path 120 that leads from the direction change valve 100 to the P froth recovery tank 110 and a C froth recovery flow path 140 that leads to the C floss recovery tank 130 branch off. Has been. A P froth return flow path 160 is connected from the P froth recovery tank 110 to the stirring tank 150, and a pump 170 is provided in the P floss return flow path 160. The slurry charging channel 30 is connected to the lower end of the stirring tank 150, and a pump 180 is provided in the middle thereof.

V stir FV obtained by the floating separation apparatus shown in FIG. 1, water, and a collecting agent (for example, kerosene) are introduced into the stirring tank 150 from above, and the stirrer 190 is rotated through the rotating shaft 210. A slurry-treated liquid is obtained, and this is introduced into the treatment tank 10 </ b> A from the floss overflow port 20 a through the slurry introduction channel 30 by the pump 180.

The liquid to be treated is dropped and accommodated in the treatment tank 10A, and the accommodated liquid to be treated is forcibly circulated through the circulation channel 60 so that microbubbles are generated in the tangential direction of the treatment tank 10A. The microbubble generator 80 rises as a swirling flow in the treatment tank 10A, and the floss F adhering to the bubbles overflows from the floss overflow port 20a and falls along the floss collection tray 20A.

A tail ash collection channel 360 is provided at the lower end of the treatment tank 10A, and the tail ash T falls from the tail ash collection channel 360 to the tail ash collection tank 370 and is collected.

The overflow Floss F is measured by the floss discrimination means 220, and the measurement data is transmitted to the direction switching valve 100 to control it.

The fallen Floss F is recovered from the Floss recovery flow path 50 and sent to the direction switching valve 100. The floss discriminating means 220 is controlled by the measurement data from the floss discriminating means 220 and the direction switching valve 100 is distributed to either the P floss recovery flow path 120 or the C floss recovery flow path 140, and the P floss FP is the P floss recovery flow path. The C floss FC is recovered in the tank 110 and the C floss recovery tank 130, respectively. Here, C froth is defined as a component having a high content of unburned carbon in the floss F (80% or more of unburned carbon).

The configuration of the floss discrimination means 220 is the same as that shown in FIGS. In addition, when obtaining C floss of ignition loss 80% or more, it can discriminate | determine as follows by what becomes a reference | standard. The measuring device using the light source and the camera has the same configuration as that used for determining the V floss. The standard differs depending on the type of ash, the brightness of the light source, the position and performance of the camera, and the density of the color sample.

When judging on the basis of time, the ignition loss is reduced to less than 80% after 15 minutes.
When the determination is made based on the luminance, the loss on ignition decreases to less than 80% when the common logarithm Log10 (Cd / m2) of the luminance is approximately 2.07 as a boundary.
When judging based on the color intensity, the ratio of the color intensities is -0.14 for red R, -0.1 for green G, and -0.13 for blue B, respectively. Thus, the ignition loss is reduced to less than 80%. Here, the negative color intensity means that the color of the floss is blacker than the black specimen used. That is, it should be noted that the color intensity is a relative value, and the color intensity ratio varies depending on the color density of the sample.

As described above, in the floating separation apparatus shown in FIG. 7, it is possible to obtain C froth having a high content rate of 80% or more of unburned carbon from V froth.

As described above, according to the method and apparatus of the present invention, instead of the floss that has been treated as waste in the past, unburned carbon has a high content of V-floss, and even higher content of C-floss. There is an advantage that it can be obtained, waste can be almost eliminated, and the amount of recovered tail ash is also increased.

DESCRIPTION OF SYMBOLS 1 ... Processing tank 2 ... Floss collection tray 2a ... Floss overflow port 8 ... Micro bubble generator 10 ... Direction switching valve 11 ... P froth collection tank 13 ... V floss collection tank 16 ... P floss return flow path 15 ... Stirring tank 20 ... Liquid to be treated 22 ... Floss discriminating means 23 ... Timer 27 ... Luminance meter 30, 31 ... Solenoid valve 32 ... Camera 110 ... P froth recovery tank 150 ... Stirring tank 130 ... C floss recovery tank 300 ... V floss recovery tank F ... Floss T ... tail ash FP ... P floss FC ... C floss FV ... V floss

Claims (10)

A separation step of separating the unburned carbon and the tail ash by flotation of the liquid to be treated in which coal ash containing unburned carbon is dispersed in water and slurried;
A floss discrimination step for discriminating the floss obtained by the flotation;
A discriminating and recovering step for discriminating and recovering the floss from V floss having a high content of unburned carbon and P floss having a low content of unburned carbon based on the discrimination result in the floss discrimination step;
A method of recovering unburnt carbon, comprising: re-introducing the recovered P-floss into the liquid to be treated and performing flotation again.   Using the recovered V floss as a liquid to be treated, a second flotation apparatus different from the flotation apparatus is used to perform flotation, and unburned carbon is recovered as C froth having a high content of 80% or more. And an unburned carbon recovery method according to claim 1, further comprising: a step. A treatment tank into which a liquid to be treated which is a slurry of unburned carbon containing fly ash and water is stirred by a stirring means, and bubbles are injected into the liquid to be treated in the treatment tank to cause overflow, and the treatment In the floating separation device that causes the froth to overflow from the froth overflow port provided in the upper part of the tank, and collects the tail ash by the recovery flow path provided in the lower part of the processing tank,
Floss discriminating means for discriminating floss based on data including at least a time from the start of overflow of the floss, a photometric value, and a color density;
A discriminating and collecting means for discriminating and collecting V-floss having a high content rate and P-floss having a low content rate by the floss discriminating means;
And a reflux means for refluxing all or part of the recovered P-floss to the treatment tank. The floss discriminating means measures the time from the start of overflow of the floss, and determines that it is the V floss if it is less than a preset time, and the P floss if it is not less than a preset time. The floating separation device according to claim 3. 4. The floating separation device according to claim 3, wherein the floss discrimination means measures light by irradiating the floss with light and determines whether the V floss or the P floss is based on a measurement result.   4. The floss determination means irradiates light with the floss, measures the intensity of the color, and determines whether it is the V floss or the P floss based on the intensity value of the color. The floating separator described.   The discriminating and collecting means includes a direction switching valve or an electromagnetic valve that operates so that the floss flows through the V floss collecting flow path or the P floss collecting flow path based on the control by the floss discriminating means, and the V floss and P floss respectively. The floating separation apparatus according to any one of claims 4 to 6, further comprising a V froth collection tank and a P froth collection tank to be collected. A V-floss recovered by the unburned carbon recovery method according to claim 1 or 2 or the floating separation device according to any one of claims 3 to 7. Tail ash recovered by the unburned carbon recovery method according to claim 1 or 2, or the floating separation device according to any of claims 3 to 7. C floss recovered by the unburned carbon recovery method according to claim 2.