JP2010125378A - System for cleaning combustion gas of coal fired boiler and operation method for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple structural and miniature system for cleaning a combustion gas of a coal fired boiler which classifies coal ash caught from the combustion gas discharged from the coal fired boiler and which can directly recover minute particle coal ash. <P>SOLUTION: The system for cleaning a combustion gas of a coal fired boiler includes a coal fired boiler burning coal as fuel, a denitrification device installed downstream of the coal fired boiler and decreasing nitrogen oxides in the combustion gas discharged from the coal fired boiler, a dust removing device installed downstream of the denitrification device and catching and recovering minute particles of coal ash contained in the combustion gas flowing down through the denitrification device, a desulfurization device placed downstream of the dust removing device and absorbing the sulfur oxides in the combustion gas flowing down through the dust removing device, and a classification device for coarse particles installed upstream of the dust removing device and installing a louver inside whose arrange angle can be adjusted and classifies the coarse particles in the coal ash contained in the combustion gas. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a combustion gas purification system for a coal fired boiler and a method for operating a combustion gas purification system for a coal fired boiler.

  A thermal power plant equipped with a coal-fired boiler has a combustion gas purification system that purifies the combustion gas discharged from the coal-fired boiler.

  As a combustion gas purification system of a thermal power plant equipped with a coal-fired boiler, for example, as described in JP-A-2002-349835, it is installed on the downstream side of a coal-fired boiler and is included in the combustion gas. A NOx removal device for removing nitrogen oxide (hereinafter referred to as NOx), a dust removal device installed downstream of the NOx removal device to remove coal ash contained in combustion gas, and a downstream of the dust removal device A technique including a desulfurization device that is installed and removes sulfur oxide (hereinafter referred to as SOx) is disclosed.

Although not described in Japanese Patent Application Laid-Open No. 2002-349835, a catalyst is inserted in the denitration apparatus to promote the reaction between ammonia (hereinafter referred to as NH ₃ ) injected as a reducing agent and NOx. It is configured to denitrate by converting to nitrogen (hereinafter referred to as N ₂ ).

  In addition, a dust collector that removes coal ash contained in the combustion gas is used in the dedusting device, and a wet desulfurization device that absorbs and removes SOx in the combustion gas is used in the desulfurization device. .

  Usually, a dry electrostatic precipitator (hereinafter referred to as dry EP) that charges and removes coal ash is used as the dedusting device. As the desulfurization device, SOx is sprayed by spraying limestone slurry into the combustion gas. Wet desulfurization equipment that absorbs gypsum is used.

  The coal ash dedusted by this dry EP is effectively used as fly ash cement and concrete admixture.

  The quality of fly ash is standardized in JIS A6201-1999. The lower the unburned content in the coal ash, and the lower the coarse ash of 45 μm or more, the higher the quality.

  The dry EP that charges and removes coal ash in the combustion gas is configured to collect coarse ash on the upstream side and fine ash on the downstream side.

  Fine ash collected on the downstream side of the dry EP can be effectively used as high-quality ash. On the other hand, among the coarse ash collected on the upstream side of the dry EP, there is coal ash that is disposed of without being effectively used.

  In recent years, depletion of landfills has become a problem, and volume reduction or effective utilization of landfilled coal ash has become a problem.

  Therefore, for example, Japanese Patent Application Laid-Open No. 2006-233408 discloses a technique for effectively utilizing coal ash by producing coal and making fly ash fiber that is made into slag by blowing air to the molten slag. Is disclosed.

  Japanese Patent Application Laid-Open No. 8-266830 discloses a raw powder of unburned residual coal ash collected and stored for coal ash with a large amount of unburned matter that cannot be used as fly ash cement or concrete admixture. In order to classify the ash, a technique is disclosed in which coarse ash with a large amount of unburned matter is removed using a louver classifier, and fine coal ash that can be used as a fly ash cement or a concrete admixture is extracted.

  JP-A-10-300020 discloses a combustion gas purification system for a pressurized fluidized bed boiler that burns coal in a paste form to collect ash contained in the combustion gas supplied from the pressurized fluidized bed boiler. As a dedusting device, a first-stage dedusting device that collects coarse ash and a second-stage dedusting device that collects fine ash are installed in series and collected by the first-stage dedusting device. By storing coarse ash in a hopper and returning the coarse ash stored in the hopper back to the boiler with a pressurized fluid, only the collected coarse ash is returned to the boiler and the pressurized fluidized bed boiler. A technique for preventing wear of turbine blades of a gas turbine driven by a combustion gas supplied from a gas turbine is disclosed.

JP 2002-349835 A JP 2006-233408 A JP-A-8-266830 Japanese Patent Laid-Open No. 10-300020 JIS A6201-1999

In the above-described conventional combustion gas purification system for coal fired boilers, classification is performed to classify coal ash to obtain fine coal ash by classifying coal ash collected from the combustion gas discharged from the coal fired boiler. In addition to installing a vessel, a hopper for storing coal ash collected from the combustion gas and a gas source supply facility for air-carrying the coal ash stored in this hopper are installed, or coal ash that is air-carrying Since it is necessary to install another dust removing device that classifies the dust and collects fine particles, the configuration of the combustion gas purification system of the coal fired boiler is complicated and large in order to install these devices There is.

  The object of the present invention is to simplify the combustion gas of a coal-fired boiler with a simple structure that can classify coal ash collected from the combustion gas discharged from a coal-fired boiler and directly collect fine-grained coal ash. An object of the present invention is to provide a method for operating a purification system and a combustion gas purification system for a coal fired boiler.

A combustion gas purification system for a coal-fired boiler according to the present invention includes a coal-fired boiler that burns coal as fuel, and nitrogen oxides in the combustion gas that is installed downstream of the coal-fired boiler and discharged from the coal-fired boiler A denitration device that reduces the amount of coal ash contained in the combustion gas that is installed downstream of the denitration device and flows down the denitration device, and a dedusting device A desulfurization device that absorbs sulfur oxides in the combustion gas that has been installed downstream and flows down the dedusting device is installed, and coarse particles of coal ash contained in the combustion gas are disposed upstream of the dedusting device. A coarse-grain classifier equipped with a louver that can be adjusted in the angle at which it is arranged is provided.

  A combustion gas purification system for a coal fired boiler according to the present invention includes a coal fired boiler that burns coal as fuel, and nitrogen oxidation in a combustion gas that is installed downstream of the coal fired boiler and discharged from the coal fired boiler. A denitration device that reduces waste, a dedusting device that is installed downstream of the denitration device and collects and collects fine particles of coal ash contained in combustion gas flowing down the denitration device, and the dedusting device A desulfurization device that absorbs sulfur oxides in the combustion gas that has flowed down the dedusting device and is installed on the downstream side of the dedusting device is installed, and coarse particles out of the coal ash contained in the combustion gas inside the dedusting device A coarse-grain classifier equipped with a louver that can adjust the arrangement angle for the classification is installed.

  The operation method of the combustion gas purification system of the coal fired boiler according to the present invention is a denitration apparatus installed on the downstream side of the coal fired boiler, in which fuel coal is mixed with air and burned in the coal fired boiler to generate combustion gas. And reducing the nitrogen oxides in the combustion gas discharged from the coal-fired boiler, and the coal-fired by a louver provided in a coarse particle classifier installed downstream of the denitration device. Combustion in which coarse particles are classified and removed from coal ash contained in the combustion gas discharged from the boiler, and then flowed down the coarse particle classifier using a dust removing device installed downstream of the coarse particle classifier. Fine particles of coal ash contained in the gas are collected and recovered, and sulfur oxides in the combustion gas flowing down the dedusting device are absorbed by the desulfurization device installed on the downstream side of the dedusting device. It is characterized by that.

  According to the present invention, the combustion of a small-sized coal-fired boiler with a simple configuration capable of classifying coal ash collected from combustion gas discharged from a coal-fired boiler and directly collecting fine-grained coal ash An operation method of the gas purification system and the combustion gas purification system of the coal fired boiler can be realized.

  Next, a method for operating a combustion gas purification system for a coal fired boiler and a combustion gas purification system for a coal fired boiler according to an embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an embodiment of a combustion gas purification system for a coal fired boiler according to the present invention.

  In the coal combustion gas purification system for effective utilization of coal ash according to the present embodiment shown in FIG. 1, the coal-fired boiler 1 is supplied with fuel coal 20 and combustion air 21 to burn the fuel coal, and the high temperature The combustion gas is generated.

  The temperature of the combustion gas produced | generated inside the coal burning boiler 1 becomes a high temperature of about 1600-1800 degreeC.

  This high-temperature combustion gas is reduced in temperature by heat exchange with a heat exchanger 4 that generates steam to be supplied to a steam demand destination installed in the coal fired boiler 1, and a denitration device installed downstream of the coal fired boiler 1 22 is supplied.

In the denitration device 22, NH ₃ is supplied as a reducing agent, and the NOx concentration contained in the combustion gas is reduced to N ₂ by bringing the denitration catalyst filled in the denitration device 22 into contact with the combustion gas, whereby the concentration of NOx is reduced. Reduce.

  The combustion gas 5 flowing down the denitration device 22 is installed on the downstream side of the denitration device 22 and supplied to the air preheater 2 that preheats the combustion air supplied to the coal-fired boiler 1. The air 21 taken in from the outside by the forced draft fan (hereinafter referred to as FDF) 6 and the combustion gas 5 are heat-exchanged at 2, and the combustion gas 5 whose temperature is further reduced is coarse particles having a louver 30 inside. It is supplied to the classifier 3.

  The air heated by the air preheater 2 by heat exchange with the combustion gas 5 is used as combustion air 21 in the coal fired boiler 1.

  The combustion gas 5 supplied from the air preheater 2 to the coarse particle classifier 3 is provided inside the coarse particle classifier 3 and flows down between a plurality of louvers 30 whose installation angles are adjusted. The coarse particles of coal ash having a particle size of 45 μm or more are removed by colliding the coarse particles larger than 45 μm in the coal ash contained in the combustion gas 5 with the louver 30 and dropping the coarse particles. The

  Further, the combustion gas 5 from which coarse particles have been removed by the coarse particle classifier 3 from the coal ash flowing down the coarse particle classifier 3 is a dry EP9 which is a dedusting device installed on the downstream side of the coarse particle classifier 3. Flow into.

  The dry EP9 is configured to charge and remove the coal ash in the combustion gas, and a recovery chamber (collecting chamber (collecting points) for collecting the coal ash installed inside the dry EP9 ( The upstream recovery chamber has a fine grain 1 ash that is relatively larger in size than the 2 ash fine particles, and the downstream recovery chamber has a fine 2 ash). Ashes are recovered.

The combustion gas 5 from which the coal ash has been removed by flowing down the dry EP 9 is supplied to a desulfurization apparatus 10 installed on the downstream side of the dry EP 9, and limestone (CaCO ₃ ) and water are mixed in the desulfurization apparatus 10. The slurry is sprayed on the combustion gas 5, and SOx in the combustion gas 5 is absorbed and removed by gas-liquid contact.

  And the combustion gas 5 discharged | emitted from the said desulfurization apparatus 10 is discharge | released in air | atmosphere through the chimney 11. FIG.

  Incidentally, the quality of fly ash, which is coal ash removed from the combustion gas 5 in the dry EP9, is standardized according to JIS A6201-1999.

  The quality of fly ash is specified from 1 to 4 in order of suitability as a concrete admixture, among which unburned matter and particle size in coal ash are specified.

  1 type of fly ash is 3% or less unburned, 10% or less of particle size 45μm or more, 2 types of fly ash is 5% or less of unburned particle size, 40% or less of particle size 45μm or more, 3 types of fly ash are unburned 8% or less, a particle size of 45 μm or more is 40% or less, and four types of fly ash have an unburned content of 5% or less, and a particle size of 45 μm or more is 70% or less.

  Therefore, the dust removal performance required for the coarse particle classifier 3 is the ability to remove coal ash having a particle size of 45 μm or more.

  The dust removal performance of the dry EP9 is 98% or more in terms of dust removal, and the dry EP9 shown in FIG. 1 has two recovery chambers for collecting coal ash installed inside the dry EP9. The upstream collection chamber is called 1 ash, and the downstream collection chamber is called 2 ash.

  Of the coal ash removed and recovered by the dry EP9, coarse particles are collected in the collection chamber at the upstream collection site, and fine particles are collected in the collection chamber at the downstream collection site. Therefore, the 1st ash in the upstream collection chamber has many coarse particles, and the 2nd ash in the downstream collection chamber has many fine particles.

  Therefore, since the two-zone ash has many fine particles, it can be effectively used as it is as a high quality coal ash that is adapted to JIS standard fly ash 1 type unburned 5% or less and particle size 45 μm or more 40% or less.

  In the combustion gas purification system for a coal fired boiler according to this embodiment, as shown in FIG. 1, coarse particles having a louver 30 with an adjustable arrangement angle for classifying coarse particles on the upstream side of the dry EP9. The classifier 3 is installed, and as described above, coarse particles having a particle diameter larger than 45 μm are removed from the coal ash contained in the combustion gas 5 by the coarse particle classifier 3.

  For this reason, in the dry EP9 installed on the downstream side of the coarse particle classifier 3, not only the two-zone ash of the downstream recovery chamber, which is the location for collecting fine coal ash, but also the upstream recovery chamber Coal ash collected by the 1st ash can be reduced in coarse particles, and in addition to the high quality fine 2nd ash that can be effectively used as it is, the 1st ash can also be used as it is. Diameter coal ash can be obtained.

  The fine ash particles collected in the upstream collection chamber inside the dry EP 9 are periodically taken out through the discharge channel 41 and collected in the downstream collection chamber. The grains are configured to be periodically taken out through the discharge channel 42.

  In addition, the 1 ash collected in the collection chamber at the upstream collection point installed inside the dry EP9 is periodically extracted and supplied to the particle size distribution measuring device 31 provided in the dry EP9. The distribution meter 31 measures the particle size distribution of the coal ash of the first ash.

  The measurement data of the particle size distribution of 1 ash measured by the particle size distribution measuring device 31 of the dry EP9 is the angle of a plurality of louvers 30 installed inside the coarse particle classifier 3 installed upstream of the dry EP9. The louver angle is calculated by calculating the optimum louver angle based on the measurement data of the particle size distribution of the first ash measured by the particle size distribution measuring device 31 in the control device 32. A command signal is output to the louver 30 of the classifier 3, and the louver 30 of the coarse particle classifier 3 is operated at an appropriate angle so that the coarse particles having a particle diameter of 45 μm or more among the coal ash contained in the combustion gas 5. Is to collide with the louver 30 and drop to remove coarse particles having a particle size of 45 μm or more.

  That is, in the measurement data of the particle size distribution of the first ash measured by the particle size distribution measuring device 31, the horizontal axis represents the coal ash particle size (μm), and the vertical axis represents the cumulative volume ratio (%). In this case, it is expressed as a curve as shown in FIG. The position of the coal ash particle size of 45 μm is shown as a dotted line in FIG.

  High quality coal with 1 ash collected in the recovery chamber on the upstream side of the dry EP9 that is less than 5% unburned JIS standard fly ash and less than 40% particle size 45μm In order to fill the ash, by adjusting the louver 30 of the upstream coarse particle classifier 3 to an appropriate angle, coarse particles having a particle size larger than 45 μm among the coal ash contained in the combustion gas 5 are obtained. It needs to be removed.

  Therefore, in the control device 32, the particle size distribution of 45 μm is a cumulative volume ratio as shown in the solid line A curve in FIG. The control device 32 outputs a command signal to the louver 30 of the coarse particle classifier 3 so as to maintain a particle size distribution of 90% to 93%, and the louver 30 is adjusted to an appropriate angle to adjust the coarse particle. The classifier 3 classifies and removes coarse particles having a particle size larger than 45 μm from the combustion gas 5.

  For example, when the measurement data of the particle size distribution of the first ash measured by the particle size distribution measuring device 31 is the particle size distribution shown as a curve of the solid line A in FIG. Since the quality of one kind of fly ash of JIS standard is satisfied, the command signal is not output from the control device 32 and the angle of the louver 30 of the coarse classifier 3 is While maintaining the state as it is, the coarse particle classifier 3 classifies and removes coarse particles having a particle size larger than 45 μm from the combustion gas 5.

  Further, when the measurement data of the particle size distribution of the first ash is the particle size distribution shown as a curve of the broken line B in FIG. 8, the coal ash having a particle size of 45 μm is not supplemented by the coarse particle classifier 3 and is downstream. Since the control device 32 calculates an optimum louver angle and outputs a command signal for operating the louver 30 angle, the louver of the coarse particle classifier 3 is shown. 30 is adjusted so that the angle becomes larger with respect to the flow of the combustion gas, and coarse particles having a particle size larger than 45 μm are classified and removed from the combustion gas 5 by the coarse particle classifier 3.

  In addition, when the measurement data of the particle size distribution of the first ash is the particle size distribution shown as a curve of the one-dot chain line C in FIG. 8, the coal ash having a particle size of 45 μm is supplemented by the coarse particle classifier 3 too much. Therefore, the control device 32 calculates an optimum louver angle and outputs a command signal for manipulating the angle of the louver 30. The louver 30 of the coarse particle classifier 3 is angled with respect to the flow of combustion gas. The coarse particles having a particle size larger than 45 μm are classified and removed from the combustion gas 5 by the coarse particle classifier 3.

  As a result, the particle size distribution of the first ash collected in the collection chamber of the upstream collection point installed in the dry EP9 is monitored, and the angle of the louver 30 of the coarse particle classifier 3 is set appropriately. By adjusting the angle, it becomes possible to accurately adjust the particle size of the coal ash of the 1st ash to be collected into fine particles, and not only the 2nd ash composed of high precision fine particles but also the 1st ash It is possible to stably obtain coal ash that conforms to the JIS standard fly ash class 1 and corresponding to the stipulation that the unburned content is 3% or less and the particle size of 45 μm or more is 10% or less.

  Next, the coarse particle classifier 3 used in the combustion gas purification system of the coal fired boiler of this embodiment shown in FIG. 1 will be described with reference to FIG.

  A top view of the coarse particle classifier 3 is shown in the upper part of FIG. 2 and a side view of the coarse particle classifier 3 is shown in the lower part. The coarse particle classifier 3 is a louver type coarse particle having a louver 30 inside. A classifier is used. The louver type coarse particle classifier 3 is a dust removing device that utilizes the difference in inertial force between airflow and dust.

  The louver 30 is obtained by attaching a plurality of plates in parallel to the coarse particle classifier 3 with a certain distance and angle in parallel. A plurality of the louvers 30 are arranged in the height direction of the coarse particle classifier 3. It has a configuration.

  And the combustion gas 5 which flowed down one by one through the coal-fired boiler 1, the denitration device 22 and the air preheater 2 installed on the upstream side, and the coal ash accompanying the combustion gas 5 flow into the coarse particle classifier 3.

  Coal ash having a particle size larger than 45 μm out of the coal ash flowing into the coarse particle classifier 3 collides with the louver 30 attached to the coarse particle classifier 3 and is collected.

  Further, among the coal ash flowing into the coarse particle classifier 3, fine particles having a particle size smaller than 45 μm and the combustion gas 5 pass through the gap between the louvers 30 attached inside and flow down to the dry EP 9 on the downstream side.

  If the louver 30 installed inside the coarse particle classifier 3 is set to an angle at which the inclination of the louver 30 increases with respect to the flow direction of the combustion gas 5 flowing down inside the coarse particle classifier 3, The number of coal ash particles that collide with 30 increases, and the dust removal rate increases.

  On the other hand, if the louver 30 is inclined toward the horizontal direction where the inclination of the louver 30 is small with respect to the flow direction of the combustion gas 5, the number of coal ash particles colliding with the louver 30 is reduced, and the dust removal rate is lowered.

  Further, whether or not the coal ash particles collide with the louver 30 of the coarse particle classifier 3 depends on the particle diameter and specific gravity of the particles. Since the particle size and specific gravity of coal ash differ depending on the type of coal and the particle size when the coal is pulverized, the installation angle of the louver 30 is adjusted according to the operation of the coarse particle classifier 3, and the dust removal rate is adjusted. It is desirable to do.

  Next, a modification of the coarse particle classifier 3 shown in FIG. 2 will be described with reference to FIG.

  A top view of the coarse particle classifier 3 is shown in the upper part of FIG. 3 and a side view of the coarse particle classifier 3 is shown in the lower part of the louver type coarse particle classifier 3 of this modification. A plurality of louvers 30 are arranged in the width direction of the coarse particle classifier 3 by attaching the plates in parallel to the coarse particle classifier 3 with a certain interval and angle.

  By the way, mercury is a problem as a trace harmful substance in the combustion gas 5 discharged from the coal-fired boiler 1. Mercury exists in the combustion gas 5 as gaseous metallic mercury and reacts with chlorine to produce mercury chloride gas.

  Gaseous metallic mercury itself is hardly adsorbed on the coal ash contained in the combustion gas 5, but the mercury chloride gas is easily adsorbed on the coal ash contained in the combustion gas 5.

  Further, several percent of SOx gas in the combustion gas 5 discharged from the coal-fired boiler 1 becomes sulfur trioxide gas, and this sulfur trioxide gas is adsorbed on coal ash contained in the combustion gas.

  Moreover, in the location where sulfur trioxide gas falls below the acid dew point, it becomes sulfuric acid mist, which causes corrosion of equipment piping. The coarse particle classifier 3 is desirably used at a temperature equal to or higher than the acid dew point of the sulfur trioxide gas.

  For the reasons described above, the amount of mercury released into the atmosphere can be reduced by increasing the amount of mercury chloride gas and sulfur trioxide gas in the combustion gas 5 discharged from the coal-fired boiler 1 and adsorbed to the coal ash. Corrosion can also be suppressed.

  Next, another modification of the coarse particle classifier 3 shown in FIG. 2 will be described with reference to FIG.

  FIG. 4 shows a new louver structure installed in the coarse particle classifier 3 of this modification. The louver 30a of this embodiment flows down inside the coarse particle classifier 3 as shown in FIG. The louver 30a adopts a wedge-shaped louver 30a in which a plurality of louver crests 30b and louver troughs 30c are continuously formed with respect to the flowing direction of the combustion gas 5.

  By disposing the wedge-shaped louver 30a inside the coarse particle classifier 3, a large number of vortex flows 5b are formed in the combustion gas 5 flowing down in the flow path between the adjacent wedge-shaped louvers 30a. Thus, the residence time of the combustion gas 5 can be earned.

  As a result, the mercury chloride gas and the sulfur trioxide gas in the combustion gas 5 can sufficiently come into contact with the combustion gas 5 that stays and flows down in the gap between the wedge-shaped louvers 30a. The amount of ash adsorption by which mercury chloride gas and sulfur trioxide gas are adsorbed on the coal ash contained in the gas 5 is increased.

  The shape of the louver 30a shown in FIG. 4 may be a corrugated shape in which a louver crest 30b and a louver trough 30c are continuously curved.

  In the above-described coal combustion gas purification system for effective utilization of coal ash according to this embodiment, a louver classifier is used as the coarse particle classifier 3, but the coarse particle classifier 3 can classify coarse particles. The classifier may have a configuration in which a collision plate that operates in the same manner as the louver is installed therein. Moreover, it may replace with the coarse particle classifier 3 of a present Example, and the cyclone classifier using the airflow classifier using a sedimentation speed difference and the centrifugal force difference may be sufficient.

  According to the present embodiment, a small-sized coal-fired boiler with a simple configuration capable of classifying coal ash collected from combustion gas discharged from a coal-fired boiler and directly collecting fine-grained coal ash. An operation method of the combustion gas purification system and the combustion gas purification system of the coal fired boiler can be realized.

  FIG. 5 shows another embodiment of the combustion gas purification system for a coal fired boiler according to the present invention.

  The combustion gas purification system of the coal fired boiler of this embodiment shown in FIG. 5 has the same general configuration as the combustion gas purification system of the coal fired boiler of the previous embodiment shown in FIG. The description is omitted, and different configurations will be described below.

  In this embodiment shown in FIG. 5, the dry EP9a having the function of the coarse particle classifier 3 shown in FIG. 1 is adopted by installing the louver 30 in the previous stage inside the dry EP9a. .

  Then, by the louver 30 installed in the previous stage inside the dry EP9a, coarse particles having a particle size of 45 μm or more out of coal ash contained in the flowing down combustion gas 5 are collided with the louver 30 and coarse particles having a particle size of 45 μm or more. It is configured to remove the grains.

  Further, in the dry EP9a, coarse particles having a particle size of 45 μm or more are removed by colliding with coal ash contained in the combustion gas 5 by the louver 30 installed in the previous stage inside the dry EP9a. Of the multiple collection chambers that collect and collect installed coal ash, the 1st ash collected and collected in the collection chamber of the third collection site from the upstream side is discharged. Similarly, the second ash collected and collected in the collection chamber of the fourth collection point from the upstream side is also periodically extracted to the outside through the discharge channel 42. It is configured as follows.

  Further, the first ash recovered in the third recovery chamber from the upstream side inside the dry EP9 is fed to a particle size distribution measuring device 31 attached to the dry EP9a. The particle size distribution of the coal ash of the first ash is measured.

  And the measurement data of the particle size distribution of the first ash measured by the particle size distribution measuring device 31 of the dry EP9a is input to the control device 32 for adjusting the angle of the louver 30 installed in the previous stage inside the dry EP9a, The control device 32 calculates an optimum louver angle based on the measurement data of the particle size distribution of the first ash measured by the particle size distribution measuring device 31, outputs a command signal, and is installed in the dry EP9a. Operate 30 to the appropriate angle and adjust.

  As a result, the particle size distribution of the first ash collected in the third recovery chamber from the upstream side installed in the dry EP9 is monitored, and the angle of the louver 30 of the coarse particle classifier 3 is set to an appropriate angle. It is possible to accurately adjust the particle size of the coal ash of the 1st ash collected to be fine, and not only the 2nd ash consisting of high precision fine particles but also the 1st ash is stable. Thus, coal ash corresponding to the JIS standard fly ash type 1 can be obtained that meets the regulations of 3% or less unburnt and 10% or less with a particle size of 45 μm or more.

  In the dry EP9a, the areas charged with coal ash are the 3rd and 4th areas which are the third and fourth collection points from the upstream side installed in the dry EP9a.

  The first ash recovered in the plurality of recovery chambers for recovering the coal ash collected at the third collection point from the upstream side of the dry EP9a in the present embodiment shown in FIG. In dry EP9 of an Example, it corresponds to the 1st ash collected and collect | recovered in the collection | recovery chamber of the 1st collection location from the upstream.

  Therefore, in this example, the particle size distribution of the dry ash of the dry EP9a is measured by the particle size distribution measuring device 31, and the measurement data of the particle size distribution of the single ash measured by the particle size distribution measuring device 31 is the dry type. Based on the measurement data of the particle size distribution of the 1 ash which is input to the control device 32 for adjusting the angle of the louver 30 installed in the front stage of EP9a and is measured by the particle size distribution measuring device 31 in the control device 32. An optimum louver angle is calculated and a command signal is output, and the louver 30 installed in the previous stage of the dry EP 9a is adjusted to an appropriate angle.

  As a result, the particle size distribution of the first ash collected in the collection chamber of the upstream collection point installed in the dry EP9 is monitored, and the angle of the louver 30 of the coarse particle classifier 3 is set appropriately. By adjusting the angle, it becomes possible to accurately adjust the particle size of the coal ash of the 1st ash to be collected into fine particles, and not only the 2nd ash composed of high precision fine particles but also the 1st ash It is possible to stably obtain coal ash that conforms to the JIS standard fly ash class 1 and corresponding to the stipulation that the unburned content is 3% or less and the particle size of 45 μm or more is 10% or less.

  According to the present embodiment, a small-sized coal-fired boiler with a simple configuration capable of classifying coal ash collected from combustion gas discharged from a coal-fired boiler and directly collecting fine-grained coal ash. An operation method of the combustion gas purification system and the combustion gas purification system of the coal fired boiler can be realized.

  FIG. 6 shows another embodiment of the combustion gas purification system for a coal fired boiler according to the present invention.

  The combustion gas purification system for the coal fired boiler of this embodiment shown in FIG. 6 has the same general configuration as the combustion gas purification system for the coal fired boiler of the previous embodiment shown in FIG. The description is omitted, and different configurations will be described below.

  In the present embodiment shown in FIG. 6, GGH heat recovery for exchanging heat with the combustion gas 5 flowing down the air preheater 2 at a position downstream of the air preheater 2 and upstream of the coarse particle classifier 3. A vessel 24 is installed.

  Further, a GGH reheater 25 for exchanging heat with the combustion gas 5 flowing down the desulfurization device 10 is installed at a position downstream of the desulfurization device 10 and upstream of the chimney 11.

  Between the GGH heat recovery unit 24 and the GGH reheater 25, a circulation channel 27 for circulating the heat medium 26 used in the GGH heat recovery unit 24 and the GGH reheater 25 is disposed.

  A heat medium 26 that flows through a circulation flow path 27 disposed between the GGH heat recovery device 24 and the GGH reheater 25 is used as a heat medium for the GGH reheater 25 installed downstream of the desulfurization apparatus 10. And it becomes possible to prevent the white smoke of the combustion gas emitted from the chimney 11 to the atmosphere by raising the temperature of the exhaust gas at the outlet of the desulfurization apparatus 10.

  In the present embodiment, the particle size distribution of the first ash of dry EP9 is measured by the particle size distribution measuring device 31, and the measurement data of the particle size distribution of the first ash measured by the particle size distribution measuring device 31 is sent to the control device 32. The control device 32 calculates an optimum louver angle based on the measurement data of the particle size distribution of the first ash measured by the particle size distribution measuring device 31 in the control device 32 and outputs a command signal, and the coarse particle classification The angle of the louver 30 installed inside the vessel 3 is configured to be adjusted by operating to an appropriate angle.

  As a result, the particle size distribution of the first ash collected in the collection chamber of the upstream collection point installed in the dry EP9 is monitored, and the angle of the louver 30 of the coarse particle classifier 3 is set appropriately. By adjusting the angle, it becomes possible to accurately adjust the particle size of the coal ash of the 1st ash to be collected into fine particles, and not only the 2nd ash composed of high precision fine particles but also the 1st ash It is possible to stably obtain coal ash that meets the stipulations that the unburned content corresponding to one type of fly ash of JIS standard is 3% or less and the particle size of 45 μm or more is 10% or less.

  In the case of the present embodiment, the coarse particle separator 3 is installed between the GGH heat recovery device 24 and the dry EP9.

  Further, instead of the dry EP9 of this embodiment, a louver 30 is provided in the front stage of the dry EP9a as in the configuration of the dry EP9a of the embodiment shown in FIG. 5, and the function of the coarse particle classifier is provided in the dry EP9a. You may do it.

  According to the present embodiment, a small-sized coal-fired boiler with a simple configuration capable of classifying coal ash collected from combustion gas discharged from a coal-fired boiler and directly collecting fine-grained coal ash. An operation method of the combustion gas purification system and the combustion gas purification system of the coal fired boiler can be realized.

FIG. 7 shows still another embodiment of the combustion gas purification system for a coal fired boiler according to the present invention.

  The combustion gas purification system for the coal fired boiler of this embodiment shown in FIG. 7 has the same general configuration as the combustion gas purification system for the coal fired boiler of the previous embodiment shown in FIG. The description is omitted, and different configurations will be described below.

  In the present embodiment shown in FIG. 7, the GGH heat recovery unit having the function of the coarse particle classifier 3 shown in FIG. 6 by installing the louver 30 in the rear stage inside the GGH heat recovery unit. 24a is adopted.

  A plurality of recovery chambers for recovering the collected coal ash are installed in the rear stage of the GGH heat recovery unit 24a, and a louver 30 is installed in the rear stage of the GGH heat recovery unit 24a. The GGH heat recovery unit 24a has the function of the coarse particle classifier 3 shown in FIG.

  In the present embodiment, the particle size distribution of the first ash of dry EP9 is measured by the particle size distribution measuring device 31, and the measurement data of the particle size distribution of the first ash measured by the particle size distribution measuring device 31 is sent to the control device 32. The GGH heat recovery is performed by calculating an optimum louver angle based on the measurement data of the particle size distribution of the first ash measured by the particle size distribution measuring device 31 in the control device 32 and outputting a command signal. The angle of the louver 30 installed at the rear stage inside the vessel 24a is adjusted to be adjusted to an appropriate angle.

  As a result, the louver 30 installed in the GGH heat recovery unit 24a is monitored by monitoring the particle size distribution of the first ash collected in the collection chamber of the upstream collection site installed in the dry EP9. By adjusting the angle of the ash to an appropriate angle, it becomes possible to accurately adjust the particle size of the coal ash of the 1st ash collected by the dry EP9 to a fine granule, and the 2nd ash composed of high precision fine particles In addition to the above-mentioned 1 ash, coal ash can be stably obtained that conforms to the regulations of unburned 3% or less and particle size 45 μm or more and 10% or less corresponding to JIS standard fly ash.

  Further, in the combustion gas purification system for a coal fired boiler according to the present embodiment, combustion is performed in the GGH reheater 25 installed in the downstream of the desulfurization apparatus 10 in the same manner as the combustion gas purification system for a coal fired boiler shown in FIG. Since the temperature of the gas is raised, it is possible not only to prevent the white smoke of the combustion gas released from the chimney 11 to the atmosphere, but also the GGH heat recovery device 24a and coarse particles compared to the embodiment of FIG. Since the duct for flowing down the combustion gas communicating with the classifier 3 can be omitted, a more compact configuration can be achieved.

  In the combustion gas purification system for a coal fired boiler according to the present embodiment, the GGH heat recovery device 24a is used as a coarse particle classifier that classifies coal ash collected from the combustion gas discharged from the coal fired boiler and removes coarse particles. Using the louver 30 installed inside, adjusting the louver angle based on the measured value of the particle size distribution of the 1 ash collected and collected by the dry EP9 installed downstream of the GGH heat recovery unit 24a. The combustion gas purification system for a small-sized coal-fired boiler with a simple configuration that can directly collect fine-grained coal ash obtained by classifying coal ash collected from the combustion gas discharged from a coal-fired boiler. Since it can be realized, the fine coal ash collected by the dedusting device can be effectively used directly as fly ash cement or concrete admixture.

  According to the present embodiment, a small-sized coal-fired boiler with a simple configuration capable of classifying coal ash collected from combustion gas discharged from a coal-fired boiler and directly collecting fine-grained coal ash. An operation method of the combustion gas purification system and the combustion gas purification system of the coal fired boiler can be realized.

  The present invention is applicable to a combustion gas purification system for a coal fired boiler.

The schematic block diagram which shows the combustion gas purification system of the coal fired boiler which is one Example of this invention. The schematic block diagram which shows the coarse particle classifier installed in the combustion gas purification system of the coal burning boiler of the Example of this invention shown in FIG. The schematic block diagram which shows the modification of the coarse particle classifier installed in the combustion gas purification system of the coal burning boiler of the Example of this invention shown in FIG. The schematic block diagram which shows the other modification of the coarse particle classifier installed in the combustion gas purification system of the coal burning boiler of the Example of this invention shown in FIG. The schematic block diagram which shows the combustion gas purification system of the coal fired boiler which is the other Example of this invention. The schematic block diagram which shows the combustion gas purification system of the coal fired boiler which is another Example of this invention. The schematic block diagram which shows the combustion gas purification system of the coal burning boiler which is another Example of this invention. FIG. 2 is a particle size distribution diagram of 1 ash collected by dry EP9 measured by a particle size distribution measuring device in the combustion gas purification system of the coal fired boiler of the embodiment of the present invention shown in FIG. 1.

Explanation of symbols

  1: coal-fired boiler, 2: air preheater, 3: coarse particle classifier, 5: combustion gas, 6: FDF, 9: dry EP, 10: desulfurizer, 11: chimney, 20: coal, 21: air, 22: Denitration device, 24: GGH heat recovery device, 25: GGH reheater, 26: Heat medium, 27: Circulation channel, 30: Louver, 31: Particle size distribution measuring device, 32: Louver angle control device, 41 , 42: discharge channel.

Claims (12)

  A coal-fired boiler that burns coal as fuel; a denitration device that is installed on the downstream side of the coal-fired boiler to reduce nitrogen oxides in the combustion gas discharged from the coal-fired boiler; and a downstream side of the denitration device A dust removing device that collects and collects fine particles of coal ash contained in the combustion gas that has flowed down the denitration device, and is placed downstream of the dust removal device to flow down the dust removal device. Install a desulfurization device that absorbs sulfur oxides in the combustion gas, and install a louver on the upstream side of the dust removal device that can adjust the arrangement angle for classifying coarse particles of coal ash contained in the combustion gas. A combustion gas purification system for a coal fired boiler, characterized by installing a coarse particle classifier provided inside.   A coal-fired boiler that burns coal as fuel; a denitration device that is installed downstream of the coal-fired boiler to reduce nitrogen oxides in the combustion gas discharged from the coal-fired boiler; and a downstream side of the denitration device A dust removing device that collects and collects fine particles of coal ash contained in the combustion gas that has flowed down the denitration device, and is installed downstream of the dust removal device to flow down the dust removal device. Installed a desulfurization device that absorbs sulfur oxides in the combustion gas, and inside the dedusting device has a louver with an adjustable arrangement angle for classifying coarse particles of coal ash contained in the combustion gas A combustion gas purification system for coal-fired boilers, which is equipped with a coarse-grain classifier provided in the factory. In the combustion gas purification system of the coal fired boiler according to claim 1 or 2,
A particle size distribution measuring device for measuring the particle size distribution of coal ash collected and recovered by the dust removing device, and a louver of the coarse particle classifier based on a measured value of the particle size distribution by the particle size distribution measuring device. A combustion gas purification system for a coal fired boiler, characterized in that a control device for controlling the arrangement angle of the coal fired boiler is installed.   The combustion gas purification system for a coal fired boiler according to claim 1, wherein a heat exchanger for heat recovery by heat exchange with the combustion gas flowing down the denitration device is installed downstream of the denitration device. An air preheater is installed on the downstream side of the denitration device to exchange heat with the combustion gas flowing down the denitration device and preheats combustion air supplied to the coal-fired boiler, and flowed down the air preheater A GGH heat recovery unit that exchanges heat between the combustion gas and the heat medium; and a combustion gas that is installed downstream of the desulfurization unit and flows down the desulfurization unit using the heat medium of the GGH heat recovery unit as a heating medium. A combustion gas purification system for a coal fired boiler, characterized by comprising a GGH reheater for reheating.   In the combustion gas purification system for a coal fired boiler according to claim 1, a heat exchanger for heat recovery by exchanging heat with the combustion gas flowing down the denitration device is installed downstream of the denitration device, An air preheater installed on the downstream side of the denitration device to exchange heat with the combustion gas flowing down the denitration device and to preheat combustion air supplied to the coal-fired boiler, and the coarse particle classifier A GGH heat recovery device for exchanging heat between the combustion gas flowing down the air preheater and the heat medium, and a GGH installed downstream of the desulfurization device and provided in the coarse particle classifier A combustion gas purification system for a coal-fired boiler, comprising a GGH reheater that reheats the combustion gas that has flowed down the desulfurizer using the heat medium of the heat recovery device as a heating medium.   The combustion gas purification system for a coal fired boiler according to any one of claims 1 to 4, wherein the coarse particle classifier has a configuration in which a plurality of the louvers are attached at substantially constant intervals and angles. A combustion gas purification system for a coal-fired boiler, characterized by being a louver type coarse particle classifier.   7. The combustion gas purification system for a coal fired boiler according to claim 6, wherein the louver installed in the coarse particle classifier is formed in a wedge shape or a corrugated shape with respect to the flow direction of the combustion gas. A combustion gas purification system for a coal-fired boiler.   Nitrogen oxidation in the combustion gas discharged from the coal-fired boiler using a denitration device installed downstream of the coal-fired boiler to generate combustion gas by mixing the fuel coal with air in a coal-fired boiler and burning it Of coal ash contained in the combustion gas discharged from the coal-fired boiler by a louver provided with a coarse particle classifier installed on the downstream side of the denitration device. Coarse particles are classified and removed, and coal ash fine particles contained in the combustion gas flowing down the coarse particle classifier are collected and recovered by a dust removing device installed downstream of the coarse particle classifier. An operation method of a combustion gas purification system for a coal fired boiler, characterized in that sulfur oxides in the combustion gas flowing down the dedusting device are absorbed by a desulfurization device installed on the downstream side of the dedusting device .   The operation method of the combustion gas purification system of a coal fired boiler according to claim 8, wherein the louver of the coarse particle classifier is based on a measured value of a particle size distribution of coal ash collected and recovered by the dust removing device. Coarse particles are removed from the coal ash contained in the combustion gas by controlling the arrangement angle, and fine particles are collected and recovered from the coal ash contained in the combustion gas from which the coarse particles have been removed by the dedusting device. A method for operating a combustion gas purification system for a coal-fired boiler, characterized in that:   The operation method of the combustion gas purification system of the coal fired boiler according to claim 8 or 9, wherein the particle size distribution of the coal ash collected and recovered by the dust removing device is measured, and the measured particle size distribution A method for operating a combustion gas purification system for a coal fired boiler, wherein the coarse particles of the coal ash are removed by controlling the arrangement angle of the louver of the coarse particle classifier based on the measured value.   9. The operation method of a combustion gas purification system for a coal fired boiler according to claim 8, wherein heat is recovered by exchanging heat with the combustion gas flowing down the denitration device by a heat exchanger installed downstream of the denitration device. The combustion air supplied to the coal-fired boiler is preheated by exchanging heat with the combustion gas flowing down the denitration device by an air preheater installed downstream of the denitration device constituting one of the heat exchangers. The GGH heat recovery unit installed on the downstream side of the air preheater constituting one of the heat exchangers exchanges heat between the combustion gas flowing down the air preheater and the heat medium. Coal heated by the GGH reheater installed on the downstream side of the desulfurization device constituting the same and using the heat medium of the GGH heat recovery device as a heating medium to reheat the combustion gas flowing down the desulfurization device Burning boiler The method of operating a gas cleaning system.   9. The operation method of a combustion gas purification system for a coal fired boiler according to claim 8, wherein heat is recovered by exchanging heat with the combustion gas flowing down the denitration device by a heat exchanger installed downstream of the denitration device. The combustion air supplied to the coal-fired boiler is preheated by exchanging heat with the combustion gas flowing down the denitration device by an air preheater installed downstream of the denitration device constituting one of the heat exchangers. The GGH heat recovery unit provided in the coarse particle classifier and constituting one of the heat exchangers exchanges heat between the combustion gas flowing down the air preheater and the heat medium, and downstream of the desulfurization apparatus. The GGH reheater installed on the side reheats the combustion gas flowing down the desulfurization apparatus using the heat medium of the GGH heat recovery device provided in the coarse particle classifier as a heating medium. Coal fired boiler The method of operating a gas cleaning system.

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