JP2005224672A - Dehydrating system and method for clinker and fly ash sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To satisfactorily perform dehydrating treatment for clinker and fly ash in a dehydrating tank where dehydrating treatment therefor is performed, and to prevent the discharge of large quantities of water, clinker and fly ash sludge from a discharge port in the dehydrating tank by the fly ash sludge. <P>SOLUTION: The subject system for performing dehydrating treatment to fly ash sludge including clinker produced at a boiler and fine solid components recovered from exhaust gas in a coal type thermoelectric power station is provided with: an ash precipitating tank 28 for precipitating fly ash sludge; a high molecular flocculant injection apparatus 30 injecting a high molecular flocculant into the ash precipitating tank 28; and a dehydrating tank 34 where fly ash sludge is charged from the ash precipitating tank 28, further, clinker is charged from a clinker hopper 40, and dehydration therefor is performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a system and method for dehydrating clinker and fly ash sludge generated in a coal-type thermal power plant.

  In a boiler of a thermal power plant that uses coal as fuel, the ash produced by burning the coal melts and adheres to the boiler, which solidifies and falls as a clinker to the bottom of the boiler. The clinker generated in this way is mixed with water and then charged into the dehydration tank. And after completion | finish of spin-drying | dehydration, the ash gate of a spin-drying tank is opened manually, the dehydrated clinker is discharged | emitted, and it carries out outside with a conveyor. Conventionally, in this dewatering tank, not only the clinker but also fly ash sludge, which is a mixture of fly ash and water generated in the exhaust gas dedusting tower, has been dehydrated. That is, both clinker and fly ash sludge are put into the dewatering tank, and each dewatering process is performed.

Patent Document 1 discloses a technique in which a polymer aggregating material is added to a mixture of fly ash and water so that ash is aggregated and flocked.
JP-A-6-134470

  Since the clinker and the fly ash sludge are charged into the dewatering tank at independent timings, the clinker layer and the fly ash sludge layer are alternately formed in the dewatering tank. Since fly ash sludge is in the form of fine sludge, the layer of fly ash sludge has poor dewaterability. Because of this fly ash sludge layer, the dehydration efficiency of the clinker layer, which originally has a large particle size and good drainage, is deteriorated. In addition, when discharging from the ash gate after dehydration, the fly ash sludge layer suddenly improves the flow of the ash gate, and a large amount of water, clinker and fly ash sludge are discharged from the dehydration tank, and the surroundings are submerged. There is also a problem that the cleaning work is difficult. Even in Patent Document 1, there is no mention of the above-mentioned problems associated with dehydrating clinker and fly ash sludge in the same dewatering tank.

  The present invention has been made in view of the above points. In the dehydration tank for dehydrating clinker and fly ash, the dehydration process can be performed well, and a large amount of water, clinker, and fly can be removed from the discharge port of the dehydration tank. The purpose is to prevent ash sludge from being discharged.

In order to achieve the above object, the invention described in claim 1 is a system for performing dehydration treatment of fly ash sludge containing clinker generated in a boiler in a coal-type thermal power plant and fine solid components recovered from exhaust gas. Because
A dehydration tank in which the clinker and the fly ash sludge are charged to dehydrate them;
And an injection device for injecting the polymer flocculant into the fly ash sludge before being put into the dewatering tank.

Further, the invention described in claim 4 is a method for performing dehydration treatment of fly ash sludge containing fine solid components recovered from clinker generated in a boiler and exhaust gas in a coal-type thermal power plant,
Injecting a polymer flocculant into the fly ash sludge;
Supplying the clinker to a dehydration tank;
Supplying the fly ash sludge into which the polymer flocculant has been injected to the dewatering tank.

  According to the first and fourth aspects of the invention, the fly ash sludge is put into the dewatering tank in a flocked state by introducing the polymer flocculant into the fly ash sludge before being put into the dewatering tank. The For this reason, the fly ash sludge is not solidified in the dewatering tank and the dehydrating property of the clinker is not inhibited, and the dewatering of the fly ash sludge and the clinker can be performed efficiently. Further, since the fly ash sludge is flocked, a large amount of water, clinker, and fly ash sludge are not discharged from the discharge port when discharged from the dehydration tank.

  The invention described in claim 2 is the clinker and fly ash sludge dewatering system according to claim 1, further comprising an ash settling tank for precipitating the fly ash sludge before being put into the dewatering tank. The injection device injects the polymer flocculant into the ash precipitation tank.

  The invention described in claim 3 is the clinker and fly ash sludge dewatering system according to claim 2, further comprising a neutralizing means for neutralizing the fly ash sludge before being supplied to the ash settling tank. It is characterized by providing.

  According to the present invention, in a dewatering tank that dehydrates clinker and fly ash, they can be dehydrated well, and a large amount of water, clinker, and fly ash sludge are prevented from being discharged from the discharge port of the dewatering tank. it can.

  FIG. 1 is an overall configuration diagram of a dehydration processing system 10 according to an embodiment of the present invention. This dehydration treatment system 10 dehydrates clinker generated in a boiler and fly ash sludge generated in a dedusting tower in a coal-type thermal power plant.

  In the dehydration processing system 10 shown in FIG. 1, the dedusting tower 20 is cooled by spraying water on the exhaust gas after passing through the electrostatic precipitator to facilitate the reaction in a desulfurization apparatus (not shown). When water is blown to the exhaust gas in the dedusting tower 20, fine solid components (fly ash) such as coal ash remaining in the exhaust gas are recovered as fly ash sludge together with cooling water, and are stored in the primary storage tank (drainage thickener) 22. Supplied. The fly ash sludge stored in the primary storage tank (drainage thickener) 22 is precipitated, and the supernatant water is secondarily used as cooling water for the dedusting tower 20 through the pipe 24.

  The fly ash sludge stored in the primary storage tank (drainage thickener) 22 is supplied to the neutralization tank 27 by the drainage thickener extraction pump 26, and further supplied from the neutralization tank 27 to the coagulation agitation tank 29. In the neutralization tank 27, neutralization is performed by mixing, for example, sodium hydroxide with acidic fly ash sludge.

  The coagulation agitation tank 29 is injected with the polymer coagulant from the polymer coagulant injecting device 30 in accordance with the supply amount of fly ash sludge, and further supplied from the coagulation agitation tank 29 to the ash precipitation tank 28. The polymer flocculant is conventionally used for agglomeration of particles dispersed in irrigation water or wastewater, and is made of, for example, polyvinyl chloride. In general, the polymer flocculant cannot exhibit a sufficient aggregation effect in an acidic state. Therefore, in the present embodiment, as described above, the fly ash sludge is neutralized in the neutralization tank 27 so that a high coagulation effect by the polymer coagulant can be obtained.

  Thus, by injecting the polymer flocculant into the flocculation agitation tank 29, the fly ash sludge aggregates to form a large lump (floc) and precipitates at the bottom of the ash precipitation tank 28. The flocs of the precipitated fly ash sludge are put into the dewatering tank 34 by the sludge return pump 32. The supernatant water of the ash settling tank 28 is supplied to a water storage tank 36, supplied from the water storage tank 36 to a clinker hopper 40 by an ash treatment pump 38, and also as coal ash humidification water or ash treatment miscellaneous water by a pump 42 or the like. Secondary used.

  The clinker hopper 40 is installed at the bottom of the boiler and accumulates the clinker generated in the boiler. The clinker is mixed with the water supplied to the clinker hopper 40 by the ash treatment pump 38 as described above. When the mixture of clinker and water reaches a certain amount in the clinker hopper 40, the mixture is introduced into the dehydration tank 34 via the pipe 44.

  As described above, since fly ash sludge and clinker are supplied to the dewatering tank 34 at independent timings, the fly ash sludge layer and the clinker layer are alternately formed in the dewatering tank 34. . The dewatering tank 34 is switched to the dewatering mode at an appropriate timing, and the dewatering treatment of fly ash sludge and clinker is performed. The dehydrated water is discharged from the dehydration pipe 46 at the bottom of the dehydration tank 34 and stored in the ash precipitation tank 28. After completion of the dewatering, the ash gate 50 provided on the bottom side surface of the dewatering tank 34 is manually opened, and the fly ash sludge and clinker after the dewatering treatment are discharged. The discharged fly ash sludge and clinker are carried out by the draining conveyor 52, the conveyors 54 to 64, and the like.

  As described above, in this embodiment, the fly ash sludge is precipitated as floc in the ash settling tank 28 by injecting the polymer flocculant into the coagulation stirring tank 29. For this reason, flocked fly ash sludge is introduced into the dewatering tank 34, the water permeability of the fly ash sludge layer is improved in the dewatering tank 34, and the dewaterability of the clinker layer is not hindered. Therefore, according to the present embodiment, the fly ash sludge and the clinker in the dewatering tank 34 can be dehydrated satisfactorily.

  Further, as described above, the fly ash sludge becomes floc, so that water, clinker, and fly ash sludge are not discharged from the ash gate 50 when discharged from the dehydration tank 34. Therefore, unlike the conventional case, cleaning work by discharging a large amount of water, clinker, and fly ash sludge becomes unnecessary, and the workability of the discharge work is improved.

1 is an overall configuration diagram of a dehydration processing system according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Dehydration processing system 20 Dedusting tower 22 Primary storage tank 26 Drainage thickener extraction pump 27 Neutralization tank 28 Ash precipitation tank 29 Coagulation stirring tank 30 Polymer flocculant injection device 34 Dehydration tank 36 Water storage tank 40 Clinker hopper 50 Ash gate

Claims (4)

A system for dewatering fly ash sludge containing fine solid components recovered from clinker generated in a boiler and exhaust gas in a coal-type thermal power plant,
A dehydration tank in which the clinker and the fly ash sludge are charged to dehydrate them;
A clinker and fly ash sludge dewatering system comprising an injection device for injecting a polymer flocculant into the fly ash sludge before being put into the dewatering tank.   The ash precipitation tank for precipitating the fly ash sludge before thrown into the dehydration tank is provided, The injection device injects the polymer flocculant into the ash precipitation tank. Dewatering system for clinker and fly ash sludge.   The clinker and fly ash sludge dewatering system according to claim 2, further comprising neutralizing means for neutralizing the fly ash sludge before being supplied to the ash settling tank. A method for dehydrating fly ash sludge containing fine solid components recovered from clinker generated in a boiler and exhaust gas in a coal-type thermal power plant,
Injecting a polymer flocculant into the fly ash sludge;
Supplying the clinker to a dehydration tank;
And a step of supplying fly ash sludge into which the polymer flocculant has been injected to the dewatering tank. A method for dewatering clinker and fly ash sludge.

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