JP4644636B2 - Clinker ash production promotion method and clinker ash production promoter - Google Patents

Description

  The present invention relates to a clinker ash production promoting method for promoting the production of clinker ash and a clinker ash production promoting agent used therefor.

  There are various methods for burning coal in a coal-fired power generation system. Among them, so-called pulverized coal combustion in which particles obtained by finely pulverizing coal are blown into a furnace and burned is mainly employed. By burning coal, coal ash such as clinker ash and fly ash is produced as a by-product.

  Clinker ash falls from the furnace and is also called bottom ash.

  Fly ash is the remaining soot and is a particulate that is collected with high efficiency mainly by an electrostatic precipitator. Fly ash, which occupies most of coal ash, is effectively used as a new civil engineering material such as a cement raw material, a ground improver that substitutes for sea sand, or a solidified material for soft soil. Some of them are disposed of in landfills.

  By the way, the coal used as a raw material contains, in addition to carbon, harmful elements such as boron, fluorine, selenium, arsenic, hexavalent chromium and the like in a trace amount (hereinafter, the harmful elements are referred to as “toxic trace elements”). . For this reason, in consideration of the environment, the allowable concentration of toxic trace elements from coal ash, which is a residue after burning coal, is regulated by law.

  However, there are over 100 coal types exported to Japan per year, and not all of them meet the above-mentioned regulatory values. In particular, fly ash is a particle that is vitrified only on the surface. For this reason, when coal species containing a large amount of harmful trace elements are used, even if the harmful trace elements are once trapped in the fly ash particles, they are used as ground improvers, solidification treatment materials, etc. for a long time. Later, harmful trace elements may elute from the particles.

  In contrast, clinker ash is different from fly ash in that the entire particle is vitrified, so that no harmful trace elements are eluted even if it is used for some purpose and a long time has passed. Moreover, clinker ash reacts with the volatile component derived from coal contained in coal ash, especially a sulfur content, and takes in a sulfur content as a low melting-point compound. That is, in-furnace desulfurization is performed by generating clinker ash.

As described above, clinker ash is superior to fly ash in terms of environmental conservation in that it does not elute harmful trace elements and has a desulfurization effect. In addition, various effective methods of using clinker ash have been proposed, such as artificial aggregates and soil improvement materials as disclosed in Patent Documents 1 and 2. For this reason, the demand for clinker ash is increasing rapidly, and the economic value of clinker ash is also increasing rapidly.
JP-A-2005-187531 Japanese Patent Laid-Open No. 2005-104804

  However, the amount of clinker ash generated is 3-15% of the total coal ash, which is much smaller than that of fly ash. Therefore, a technique for promoting the generation of clinker ash is desired.

  On the other hand, in addition to the dust collector, coal ash is collected even from a small amount (about 1% to 2% in total) from the economizer, the air preheater, and the denitration device. The coal ash collected from the economizer, air preheater, and denitration equipment is collectively called Cinder Ash. Since cinder ash contains a large amount of Fe and has a small amount of generation, unlike fly ash and clinker ash, it has not been used effectively.

  The present invention has been made in view of the above-described problems, and it is possible to effectively use cinder ash, and the clinker ash generation promotion method capable of promoting the generation of clinker ash and the clinker ash generation promotion used therefor. The purpose is to provide an agent.

(1) a pulverized coal as a fuel in a coal-fired power generation system of the pulverized coal combustion method for burning by blowing pulverized coal obtained by pulverizing coal into the furnace, the clinker ash produced enhancer containing combustion residues of the pulverized coal A clinker ash generation promotion method that promotes the generation of clinker ash by adding the pulverized coal combustion residue as the combustion residue of the pulverized coal , the combustion residue of the pulverized coal discharged from the economizer, the exhausted from the air preheater A clinker ash generation promotion method using cinder ash containing at least one selected from the group consisting of combustion residues of pulverized coal and combustion residues of pulverized coal discharged from a denitration apparatus.

  The present inventors have found for the first time that the production of clinker ash can be promoted by adding cinder ash, which has been conventionally landfilled and has not been effectively used, to coal as fuel. .

According to the invention of (1), the cinder ash which is a combustion residue of coal is added to coal. Cinder ash that has been conventionally landfilled contains Fe components sufficiently and Ca components slightly so as to contain 10% to 12% Fe ₂ O ₃ and 1% to 3% CaO. Since Fe component and Ca component produce low melting point compounds together with silica and aluminum contained in coal ash, the melting point of Cinder Ash itself is lowered.

  Moreover, since Cinder Ash is partly an amorphous substance, it has viscosity at a relatively low temperature (for example, about 1000 ° C.) with respect to the furnace temperature (for example, about 1300 ° C. to 1500 ° C.), which is a high temperature, Furthermore, it becomes fluidized at high temperatures. That is, the cinder ash is remelted at a relatively low temperature in the furnace.

  With the above mechanism, the added cinder ash can be melted at a low temperature. Coal-derived mineral particles and volatile components come into contact (condensate) with the surface of the cinder ash that has been softened by lowering the melting point. The contacted mineral particles and volatile components are taken into the cinder ash by gradually solidifying (vitrifying) the surface of the cinder ash. That is, mineral particles and volatile components are physically taken up by cinder ash.

  As described above, the cinder ash physically takes in the mineral particles and volatile components, and the clinker ash is generated. That is, according to the invention of (1), it is possible to promote the generation of clinker ash.

  Further, according to the invention of (1), it is possible to effectively use the cinder ash.

  In addition, the above physical uptake also occurs in harmful trace elements. Therefore, according to the invention of (1), particulate harmful trace elements that may be collected by the dust collector together with fly ash, and gaseous substances that may be contained in the desulfurization effluent. Increases the amount of harmful trace elements incorporated into clinker ash. For this reason, it is possible to prevent further elution of harmful trace elements. Moreover, since physical uptake | capture also occurs in the volatile component in exhaust gas, especially a sulfur component, it is possible to advance in-furnace desulfurization rather than the case where cinder ash is not added.

  “Harmful trace elements” refers to coal such as boron, arsenic, bromine, cyanide, chlorine, iodine, sulfur, nitrogen, phosphorus, silica, tin, titanium, vanadium, tungsten, selenium, fluorine, nickel, magnesium, manganese, etc. It is an element that can be harmful to humans.

  (2) The clinker ash formation accelerator is obtained by applying a calcium compound slurry containing at least one selected from the group consisting of quicklime slurry, limestone slurry, and slaked lime slurry to the surface of the cinder ash ( 1) The clinker ash production | generation promotion method of description.

  Cinder ash is not so high in specific gravity, and if it is put into the furnace as it is, it may be blown off to the next process due to the blowing in the furnace.

  According to the invention of (2), the specific gravity is increased by applying a calcium compound slurry containing at least one selected from the group consisting of a quicklime slurry, a limestone slurry, and a slaked lime slurry to the surface of Cinder Ash. The situation where the melt at low temperature is prevented by blowing out the cinder ash to the next process is avoided.

  Further, the calcium compound slurry is thermally decomposed by the heat in the furnace, and the calcium compound is decomposed into CaO. The Ca content in the CaO generates a low melting point compound together with silica, arsenic, and the like, which are minerals in the coal, so that the coal ash containing the added cinder ash itself has a low melting point. For this reason, as described in (1), it becomes possible to physically incorporate mineral particles and volatile components into coal ash containing cinder ash, further promoting the generation of clinker ash, It is possible to prevent further elution of harmful trace elements. Moreover, it is possible to further proceed in-furnace desulfurization.

(3) The clinker ash generation promotion method according to (1) or (2), wherein the clinker ash generation accelerator is added to the pulverized coal so that the concentration of the clinker ash generation accelerator is in a range of 0.1% by mass to 20% by mass .

  By adding so that the concentration of the clinker ash formation accelerator is in the range of 0.1% by mass or more and 20% by mass or less with respect to coal, it is possible to further promote the generation of clinker ash.

(4) by adding the pulverized coal to be fuel in coal-fired power generation system of the pulverized coal combustion method for burning by blowing pulverized coal obtained by pulverizing coal into the furnace, the pulverized coal to promote the generation of clinker ash of a clinker ash growth promoter containing combustion residues, the pulverized coal combustion residues discharged from the economizer, the fines are discharged the discharged from the air preheater pulverized coal combustion residues from the denitrification device A clinker ash growth promoter which is a cinder ash containing at least one selected from the group consisting of char residue.

  The invention of (4) captures the invention of (1) as a clinker ash production promoter, and has the same effect as (1).

  (5) The clinker ash formation accelerator is obtained by applying a calcium compound slurry containing at least one selected from the group consisting of quick lime slurry, limestone slurry, and slaked lime slurry on the surface of the clinker ash (4 ) Clinker ash formation promoter.

  The invention of (5) captures the invention of (2) as a clinker ash production promoter, and has the same effect as (2).

  (6) The clinker ash generation accelerator according to (5), wherein the concentration of the calcium compound slurry in the clinker ash generation accelerator is in a range of 0.1% by mass to 20% by mass.

  By setting the concentration of the calcium compound slurry in the clinker ash production accelerator to be in the range of 0.1% by mass or more and 20% by mass or less, the production of clinker ash can be further promoted.

  According to the present invention, since the cinder ash is remelted at a relatively low temperature in the furnace and the coal-derived mineral particles and volatile components coming into contact with the surface of the clinker ash softened by remelting are taken in, the clinker ash Generation is promoted.

  Further, according to the present invention, it is possible to effectively use cinder ash.

  In addition, particulate harmful trace elements that could be collected by the dust collector along with fly ash and gaseous harmful trace elements that could be contained in the desulfurization effluent are taken into the clinker ash. The amount increases. For this reason, it is possible to prevent further elution of harmful trace elements. Moreover, since physical uptake | capture also occurs in the volatile component in exhaust gas, especially a sulfur component, it is possible to advance in-furnace desulfurization rather than the case where cinder ash is not added.

<A: Configuration of pulverized coal combustion facility in coal-fired power generation system>
Hereinafter, an embodiment showing an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a pulverized coal combustion facility 1 in a coal-fired power generation system. Here, as shown in FIG. 1, the pulverized coal combustion facility 1 includes a coal supply unit 12 that supplies coal, a pulverized coal generation unit 14 that converts the supplied coal into pulverized coal, and a pulverized coal that burns pulverized coal. The combustion part 16, the waste gas processing part 18 which processes the waste gas produced | generated by combustion of pulverized coal, and the slurry application part 20 are provided. FIG. 2 is an enlarged view of the vicinity of the furnace 161 in the pulverized coal combustion unit 16. FIG. 3 is an example of a schematic configuration diagram of the pulverized coal combustion facility 1.

<A-1: Coal supply section>
The coal supply unit 12 includes a coal bunker 121 that stores coal, and a coal feeder 122 that supplies the coal stored in the coal bunker 121. The coal bunker 121 stores coal to be supplied to the coal feeder 122. The coal feeder 122 continuously supplies the coal supplied from the coal bunker 121 to the coal pulverized coal machine 141. Moreover, this coal feeder 122 is provided with the apparatus which adjusts the supply_amount | feed_rate of coal, and, thereby, the amount of coal supplied to the coal pulverizer 141 is adjusted. Further, a coal gate is provided at the boundary between the coal bunker 121 and the coal feeder 122, thereby preventing air from the coal feeder from flowing into the coal bunker.

<A-2: Pulverized coal generation unit>
The pulverized coal generation unit 14 includes a coal pulverized coal machine (mill) 141 that converts coal into pulverized coal capable of pulverized coal combustion, and a ventilator 142 that supplies air to the coal pulverized coal machine 141.

  The coal pulverized coal machine 141 pulverizes the coal supplied from the coal feeder 122 through the coal supply pipe to form fine pulverized coal, and is supplied from the pulverized coal and the ventilator 142. Mix with air. Thus, by mixing pulverized coal and air, the pulverized coal is preheated and dried to facilitate combustion. Air is blown onto the formed pulverized coal, thereby supplying the pulverized coal to the pulverized coal combustion unit 16.

  Examples of the type of the coal pulverized coal machine 141 include a roller mill, a tube mill, a ball mill, a beater mill, an impeller mill, and the like. However, the type of the coal pulverized coal machine 141 is not limited to these and may be any mill used in pulverized coal combustion.

<A-3: Pulverized coal combustion section>
The pulverized coal combustion unit 16 includes a furnace 161 that burns the pulverized coal generated by the pulverized coal generation unit 14, an air preheater 162 (heat exchange unit) that heats the furnace 161, and a ventilation that supplies air to the furnace 161. Machine 163.

  The furnace 161 is heated by a heater (not shown) and combusts the pulverized coal supplied from the coal pulverized coal machine 141 via the pulverized coal pipe together with the air supplied from the ventilator 163. The air preheater 162 (heat exchange unit, AH) performs heat exchange between the air (untreated gas) sent to the furnace 161 and the exhaust gas. The air preheater 162 has an ash treatment hopper 162f from which AH ash described later is discharged.

  By burning pulverized coal, coal ash (coal combustion residue) such as clinker ash and fly ash is generated as a by-product.

  The clinker ash falls from the furnace 161 to the furnace bottom and is cooled by water, and is also referred to as bottom ash. Clinker ash is porous and has drainage (water permeability) and breathability.

  The fly ash is the remaining soot and is collected (collected) by a dust collector 182 described later.

  In addition to the dust collector 182, a small amount of coal ash is collected from a secondary economizer 161 e, an air preheater 162, which will be described later, and a denitration device 181, which will be described later, in total (about 1% to 2%). The The coal ash collected from the secondary economizer 161e, the air preheater (AH) 162, and the denitration device 181 is referred to as ECO ash, AH ash, and denitration device ash, respectively, and these are collectively referred to as “cinda ash”. Since cinder ash contains a large amount of Fe and has a small amount of generation, unlike fly ash and clinker ash, it has not been used effectively. According to the present invention, it is possible to effectively use this cinder ash. In addition, the cinder ash should just contain at least 1 or more types chosen from the group of ECO ash, AH ash, and denitration apparatus ash.

Further, together with the above coal ash, exhaust gases such as sulfur oxides (SOx) such as sulfur dioxide (SO ₂ ) and sulfur trioxide (SO ₃ ), and nitrogen oxides (NOx) are generated. Furthermore, among harmful trace elements such as boron, fluorine, selenium and arsenic contained in coal, boron, fluorine and selenium are gaseous compounds such as boron oxide, hydrogen fluoride and selenium oxide. It will be present in the exhaust gas. These harmful trace element compounds are sent to the exhaust gas treatment unit 18 together with the exhaust gas and fly ash.

  The furnace 161 will be described in detail with reference to FIGS. 2 and 3. In FIG. 2, the furnace 161 has a generally inverted U shape as a whole, and the combustion gas has an inverted U shape along the arrow in the figure. After moving, after passing through the secondary economizer 161e, it is inverted again into a small U shape, and the outlet of the furnace 161 (the end of the arrow in FIG. 2) is connected to a denitration device 181 and a dust collector 182 (not shown). Yes. In the pulverized coal combustion facility 1 according to the present embodiment, the height of the furnace 161 is 40 m to 60 m, and the total length of the exhaust gas passage ranges from 200 m to 800 m.

  Below the furnace 161, a burner 161a for burning pulverized coal in the vicinity of the burner zone 161a 'in the furnace 161 and an ash treatment hopper 161f for discharging clinker ash are disposed. The clinker ash discharged from the ash treatment hopper 161 f is sent to the coal ash mixing unit 20. Further, near the top of the U-shape in the furnace 161, a furnace upper dividing wall 161b, a final superheater 161b ′, and a first reheater 161f (all of which are heat exchange units) are arranged, and further placed horizontally from there. A primary superheater 161c (heat exchange unit) is subsequently arranged. Further, a second reheater 161f ′ is provided in parallel with the horizontal primary superheater 161c, and from the vicinity of the terminal end of the horizontal primary superheater 161c, a primary economizer 161d (heat exchange unit). A secondary economizer 161e (heat exchange unit) is provided in two stages. Here, the economizer (also called ECO) is a group of heat transfer surfaces provided to preheat boiler feedwater using the heat held by the combustion gas, and below it is collected by inertial collision. An ash treatment hopper 161g for discharging coal ash, so-called ECO ash, is provided. The ECO ash discharged from the ash treatment hopper 161 g is sent to the slurry application unit 20 as cinder ash. In the present embodiment, in the furnace 161, the primary economizer 161d and the secondary economizer 161e are separately installed in two stages, but the present invention is not limited to such a form. That is, the furnace 161 may have only a single economizer.

<A-4: Exhaust gas treatment unit>
The exhaust gas treatment unit 18 includes a denitration device 181 that removes nitrogen oxides in the exhaust gas discharged from the pulverized coal combustion unit 16, and a dust collector 182 that removes fly ash in the exhaust gas discharged from the pulverized coal combustion unit 16. And a desulfurization device 183 that removes sulfur oxide in the exhaust gas, and a chimney 184 that discharges the exhaust gas treated by the desulfurization device 183 to the atmosphere.

  The denitration device 181 removes nitrogen oxides in the exhaust gas. That is, ammonia gas is injected as a reducing agent into exhaust gas at a relatively high temperature (300 to 400 ° C.), and nitrogen oxides in the exhaust gas are decomposed into harmless nitrogen and water vapor by the action of a denitration catalyst, so-called dry ammonia contact. A reduction method is preferably used. The denitration device 181 includes an ash treatment hopper 181f for discharging denitration device ash collected by inertial collision. The denitration device ash discharged from the ash treatment hopper 181 f is sent to the slurry application unit 20.

  The dust collector 182 is a device that collects fly ash in the exhaust gas with an electrode. The dust collector 182 is preferably provided in a plurality of stages. The dust collector 182 includes an ash treatment hopper 182f for discharging fly ash. The fly ash collected by the dust collector 182 is conveyed to a coal ash collection silo (not shown).

  The desulfurizer 183 removes sulfur oxides in the exhaust gas. That is, the desulfurization device 183 sprays a mixed liquid (limestone slurry) of limestone and water onto the exhaust gas, thereby absorbing the sulfur oxide contained in the exhaust gas into the mixed liquid and generating a gypsum slurry. The desulfurization device 183 generates gypsum by dehydrating the gypsum slurry. The generated gypsum is collected by a gypsum collection device (not shown).

  The chimney 184 emits the exhaust gas treated by the denitration device 181, the dust collector 182 and the desulfurization device 183 to the atmosphere.

<A-5: Slurry application part>
The slurry application unit 20 includes a mixing tank 201. The mixing tank 201 includes ECO ash discharged from the ash treatment hopper 161g of the furnace 161 (primary economizer 161d and secondary economizer 161e) of the pulverized coal combustion unit 16, and ash of the air preheater 162 of the pulverized coal combustion unit 16. This is a tank in which AH ash discharged from the processing hopper 162f and Cinder ash in which the ash removal ash 181f discharged from the denitration device 181f of the denitration device 181 of the exhaust gas treatment unit 18 are combined with calcium compound slurry. . Cinder ash and a calcium compound slurry are mixed, and the calcium compound slurry is applied to the cinder ash, whereby a clinker ash generation accelerator is generated. Here, the calcium compound slurry includes at least one selected from the group consisting of quick lime slurry, limestone slurry, and slaked lime slurry, and the clinker ash formation accelerator is a calcium compound slurry on the surface of the cinder ash. Is applied.

  In this embodiment, the clinker ash production promoter is a cinna ash coated with a calcium compound slurry, but the clinker ash production promoter is used as it is without applying the calcium compound slurry. But you can.

<B: Clinker ash production promotion method of the present invention>
The clinker ash production promotion method of the present invention is a method of promoting the production of clinker ash by adding a clinker ash production accelerator containing the combustion residue of the coal to coal as fuel in a coal thermal power generation system, The coal combustion residue is selected from the group consisting of the coal combustion residue discharged from a economizer, the coal combustion residue discharged from an air preheater, and the coal combustion residue discharged from a denitration device. The production of clinker ash is promoted by using a cinder ash containing at least one kind, and this will be described using the pulverized coal combustion facility 1 described above. Preferably, it is performed in any one of coal supply process S10, pulverized coal production process S20, and pulverized coal combustion process S30.

  This step includes coal supply step S10 for supplying coal, pulverized coal generation step S20 for pulverizing the supplied coal to generate pulverized coal, pulverized coal combustion step S30 for burning this pulverized coal, Including an exhaust gas treatment step S40 for removing nitrogen oxides, fly ash, and sulfur oxide, and a slurry application step S45, each of which includes a coal supply unit 12 of the above-described pulverized coal combustion facility 1, It is performed in the pulverized coal generation unit 14, the pulverized coal combustion unit 16, the exhaust gas processing unit 18, and the slurry application unit 20. And the clinker ash production | generation promoter addition process S50 which is the characteristics of this invention is preferably performed in either of said coal supply process S10, pulverized coal production | generation process S20, and pulverized coal combustion process S30.

<Coal supply process S10>
First, in the coal supply process, the coal stored in the coal bunker 121 is supplied to the coal pulverized coal machine 141 by the coal feeder 122. The coal supplied to the coal pulverized coal machine 141 is specifically bituminous coal, subbituminous coal, lignite, or the like, but is not limited to these coals and may be coal capable of pulverized coal combustion. That's fine.

<Pulverized coal production process S20>
Next, in the pulverized coal generation step, the coal supplied from the coal feeder 122 is pulverized by the coal pulverized coal machine 141, thereby generating pulverized coal. The generated pulverized coal is supplied to the furnace 161. At this time, the average particle size of the pulverized coal formed in the pulverized coal generation step may be a particle size range generally used in pulverized coal combustion, and generally 74 μm under 80 wt% or more. The degree of pulverization. This range can also be applied when a clinker ash formation accelerator is added.

<Pulverized coal combustion process S30>
Next, in the pulverized coal combustion process, the pulverized coal generated by the coal pulverized coal machine 141 is burned by the furnace 161. As shown in FIG. 2, pulverized coal is burned in the burner zone 161a ′, and the temperature at this time ranges from 1300 ° C. to 1500 ° C. Among the coal ash generated by combustion, the clinker ash is a downward arrow. And is discharged from the ash treatment hopper 161f. The fly ash rises along the direction of the upward arrow, passes through the superheaters (heat exchange units) 161b and 161c together with the exhaust gas, and passes through the primary economizer 161d (heat exchange unit) and the secondary economizer 161e (heat exchange unit). ) In order.

  As described above, the vicinity of the economizer is an area where the temperature is maintained at about 850 ° C. to about 900 ° C., and the heat transfer surface provided for preheating boiler feedwater using the heat held by the combustion gas. By passing through the group, heat is exchanged, and the temperature decreases. The time required for the exhaust gas to reach the vicinity of the superheater from the burner zone 161a 'is approximately 5 to 15 seconds. Then, it is sent to a denitration device 181 and a dust collecting device 182 at the subsequent stage. The coal ash produced in this pulverized coal combustion process is usually in the form of a powder having an average particle size in the range of 1 μm to 100 μm.

<Exhaust gas treatment step S40>
In the exhaust gas treatment process, the exhaust gas generated by the combustion of pulverized coal is sent to the denitration device 181, further passed through the dust collector 182 and the desulfurization device 183, and then released to the atmosphere by the chimney 184.

<Slurry coating step S45>
In the slurry application step S45, the cinder ash and the calcium compound slurry are mixed in the mixing tank 201, and the clinker ash generation accelerator in which the calcium compound slurry is applied to the cinder ash is generated.

<Clinker ash formation accelerator addition step S50>
As shown in FIG. 1, the clinker ash generation accelerator addition step S50, which is a step of adding the clinker ash generation accelerator, which is a feature of the present invention, is preferably the above coal supply step S10, pulverized coal generation step S20, pulverized powder. It is performed for any one of the charcoal combustion steps S30 (S51, S52, S53 in FIG. 1 respectively).

  In addition, the addition place of a clinker ash production | generation promoter will not be specifically limited if it is the state of coal, For example, the transfer path between coal supply process S10 and pulverized coal production | generation process S20, pulverized coal production | generation process S20, and pulverized You may perform by the transfer path between charcoal combustion process S30, etc.

  Specifically, for example, a method of supplying and mixing a clinker ash generation accelerator on a belt conveyor being transferred when transporting from the coal feeder 122 to the coal pulverized coal machine 141 (see FIG. 3), clinker ash generation A method in which an accelerator is directly charged into a coal hopper (not shown) of a coal pulverized coal machine 141, a method in which an agent inlet is provided in a pipe between the coal pulverized coal machine 141 and the furnace 161, and a combustion to the furnace 161 Examples include, but are not limited to, a method of directly charging with air. As described above, the method of the present invention does not require a new facility, and can be applied by a slight improvement of the existing facility. Therefore, the existing facility can be used effectively, which is advantageous in terms of cost.

  By adding the above clinker ash generation accelerator, in the present invention, it is possible to suppress the inflow of harmful trace elements into the desulfurization effluent regardless of the type of harmful trace elements contained in the exhaust gas. Specific examples of harmful trace elements that can suppress inflow to desulfurization wastewater are not particularly limited, but boron, arsenic, bromine, cyanide, chlorine, iodine, sulfur, nitrogen, phosphorus, silica, tin, titanium, vanadium. , Tungsten, selenium, fluorine, nickel, magnesium, manganese and the like. Among these, inflow to desulfurization effluents such as boron, fluorine and arsenic, which can be a gaseous compound, can be further suppressed.

  The clinker ash production accelerator of the present invention is a medicine containing clinker ash, and a calcium compound slurry containing at least one selected from the group consisting of quick lime slurry, limestone slurry, and slaked lime slurry on the surface of clinker ash. Preferably it is an applied drug.

  It is preferable to add the clinker ash formation accelerator so that the concentration of the clinker ash formation accelerator is 0.1 mass% or more and 20 mass% or less with respect to the coal. If it is this range, it is possible to accelerate | stimulate the production | generation of clinker ash, without giving a load to the furnace 161. FIG.

  The concentration of the calcium compound slurry in the clinker ash formation accelerator is preferably in the range of 0.1% by mass to 20% by mass. If it is this range, it is possible to accelerate | stimulate the production | generation of clinker ash.

  The concentration of the calcium compound slurry in the clinker ash generation accelerator is preferably in the range of 0.1% by mass to 20% by mass. If it is this range, it is possible to accelerate | stimulate the production | generation of clinker ash.

  When the clinker ash generation accelerator is added to coal, the cinder ash in the clinker ash generation accelerator contains a sufficient amount of the Fe component and a slight amount of the Ca component, and these Fe component and Ca component are included in the cinder ash. Since low melting point compounds are produced together with silica and aluminum, Cinder Ash itself has a low melting point.

  In addition, since Cinder Ash is partly an amorphous substance, it has a viscosity at a relatively low temperature (for example, about 1000 ° C.) with respect to a high temperature in the furnace (for example, about 1300 ° C. to 1500 ° C.), Furthermore, it becomes fluidized at high temperatures. That is, the cinder ash is remelted at a relatively low temperature in the furnace.

  Further, the calcium compound slurry in the clinker ash generation accelerator is thermally decomposed by heat in the furnace, and the calcium compound is decomposed into CaO. The Ca content in the CaO generates a low melting point compound together with minerals such as silica and arsenic, so that the coal ash containing the added cinder ash itself has a low melting point.

  With the above mechanism, the added cinder ash and coal ash other than the added cinder ash can be melted at a low temperature. Coal-derived mineral particles and volatile components come into contact (condensate) with the surface of the cinder ash and coal ash that have been softened by lowering the melting point. The contacted mineral particles and volatile components are taken into the cinder ash and the coal ash by gradually solidifying (vitrifying) the surfaces of the cinder ash and the coal ash. That is, mineral particles and volatile components are physically taken up by cinder ash and coal ash.

  When mineral particles and volatile components are physically taken into the added cinder ash and coal ash other than the added cinder ash as described above, clinker ash is generated. That is, it is possible to promote the production of clinker ash by adding a clinker ash production promoter to coal.

  In addition, the above physical uptake also occurs in harmful trace elements. Therefore, particulate harmful trace elements that may be collected by the dust collector together with fly ash, and gaseous harmful trace elements that may be contained in the desulfurization effluent are Cinder Ash and Cinder Ash. The amount taken up by other coal ash increases. For this reason, it is possible to prevent further elution of harmful trace elements. Moreover, since physical uptake | capture also occurs in the volatile component in exhaust gas, especially a sulfur component, it is possible to advance in-furnace desulfurization rather than the case where a clinker ash production | generation promoter is not added.

  In addition, according to the present invention, it is possible to effectively use cinder ash.

  According to the present invention, it is possible to promote the production of cinder ash, and it is possible to incorporate harmful trace elements and sulfur components into the clinker ash whose production is promoted. In other words, the present invention is a technology that can promote the generation of clinker ash whose demand is rapidly increasing, and thus has a large economic effect and can contribute to environmental conservation. Furthermore, the present invention is a technique capable of effectively utilizing the cinder ash that has been previously landfilled.

It is a schematic block diagram of the pulverized coal combustion facility in the coal thermal power generation system which shows one Embodiment of this invention. It is an enlarged view of the vicinity of the furnace in FIG. It is a schematic block diagram of the pulverized coal combustion facility in a coal thermal power generation system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coal dust combustion facility 12 Coal supply part 121 Coal bunker 122 Coal feeder 14 Pulverized coal production | generation part 141 Coal pulverization coal machine 142 Ventilator 16 Pulverized coal combustion part 161 Furnace 162 Air supply device 163 Ventilation machine 18 Exhaust gas treatment part 181 Denitration apparatus 182 Dust collector 183 Desulfurizer 184 Chimney 201 Mixing tank S10 Coal supply process S20 Pulverized coal generation process S30 Pulverized coal combustion process S40 Exhaust gas treatment process S45 Slurry coating process S50 Clinker ash generation accelerator addition process

Claims (6)

The pulverized coal to be fuel in coal-fired power generation system of the pulverized coal combustion method for burning by blowing pulverized coal obtained by pulverizing coal into the furnace, the addition of clinker ash processing aids containing combustion residues of the pulverized coal A clinker ash production promoting method for promoting the production of clinker ash by:
Combustion residue of the pulverized coal discharged from the economizer , combustion residue of the pulverized coal discharged from the air preheater, and combustion residue of the pulverized coal discharged from the denitration device as the combustion residue of the pulverized coal A method for promoting clinker ash generation using a cinder ash containing at least one selected from the group.   2. The clinker ash growth promoter is obtained by applying a calcium compound slurry containing at least one selected from the group consisting of a quicklime slurry, a limestone slurry, and a slaked lime slurry to the surface of the cinder ash. Clinker ash generation promotion method. The clinker ash production | generation promotion method of Claim 1 or 2 added so that the density | concentration of the said clinker ash production | generation promoter may become 0.1 to 20 mass% with respect to the said pulverized coal . Combustion residue of the pulverized coal that promotes the generation of clinker ash by adding to the pulverized coal as fuel in the coal-fired power generation system of the pulverized coal combustion method in which pulverized coal obtained by pulverizing coal is blown into the furnace and burned A clinker ash growth promoter comprising:
The pulverized coal combustion residues discharged from the economizer, the discharged from the air preheater pulverized coal combustion residues, the at least one or more kinds of the discharged from the denitration apparatus selected from the group consisting of pulverized coal combustion residues A clinker ash growth promoter that is a cinder ash.   5. The clinker ash growth promoter is obtained by applying a calcium compound slurry containing at least one selected from the group consisting of a quicklime slurry, a limestone slurry, and a slaked lime slurry to the surface of the cinder ash. Clinker ash formation accelerator.   The clinker ash production promoter according to claim 5, wherein the concentration of the calcium compound slurry in the clinker ash production promoter is in the range of 0.1 mass% to 20 mass%.

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