JPWO2010024333A1 - Coal processing method and processing system - Google Patents

Abstract

In particular, low-grade coal should be efficiently dried at low cost and efficiently in an environmentally friendly condition. The coal processing system 1 includes a coal thermal power generation facility 100, a cement manufacturing facility 200, and a coal drying processing facility 300. In the dryer 20 of the coal drying processing facility 300, the exhaust heat of the exhaust gas from the cement manufacturing facility 200 is dried. Used as heat energy for processing. The temperature of the exhaust gas is set in the range of about 80 ° C. to about 200 ° C. in the dryer 20. Further, low-grade coal such as sub-bituminous coal is dried by the dryer 20 until the total moisture becomes a predetermined moisture, that is, a moisture that does not fall below the equilibrium moisture. This makes it possible to effectively use low-grade coal with a quality equivalent to that of high-grade coal such as bituminous coal.

Description

  TECHNICAL FIELD The present invention relates to a coal processing method and a processing system for effectively using low-cost coal in coal utilization facilities at low cost and efficiently among coal.

  Due to the global increase in energy demand, the proportion of low-grade coal used in coal-fired power generation facilities is increasing year by year, and this trend is expected to increase further in the future.

  However, the use of low-grade coal with high moisture content reduces the fuel intensity of coal-fired power generation facilities. Particularly in a coal utilization facility using pulverized coal, the coal is mixed with high-temperature air for combustion, dried and pulverized, and then introduced into the boiler. For this reason, the increase in water content in coal as a fuel is not only directly linked to the deterioration in fuel intensity, but also affected by the drying capacity of the crusher, etc., so the amount of low-grade coal used must be limited. There is no situation.

  For example, a coal drying method and a drying facility disclosed in Patent Document 1 below are known as attempts to escape from such a situation. When drying low-grade coal as described above, this drying facility dries low-grade coal to 80 ° C to 150 ° C using the combustion exhaust gas after passing through the air heater of the boiler of the coal-fired power generation facility, and then dried. It is said that the later exhaust gas (exhaust gas) is supplied to an electric dust collector (electric dust collector) of a coal-fired power generation facility.

  And, after the pulverized coal accompanying the exhaust gas is removed by the electric dust collector, the exhaust gas is discharged through the desulfurization device. A scrubber (cleaning dust collector) that performs so-called wet processing is also known as a means for removing pulverized coal accompanying the exhaust gas. In this scrubber, various methods such as a reservoir type that collects dust by passing exhaust gas through the stored water, a pressurized water type that injects pressurized water into the flow of exhaust gas, and a packed bed type and a rotary type are adopted. ing.

  Normally, the transportation (coal transportation) of coal to such a coal-fired power generation facility is made of bituminous coal 501 that is high-grade coal and low-grade coal in a coal accumulation relay facility 500 called a coal center, as shown in FIG. For example, a sub-bituminous coal 502 is blended (mixed) in a coal blending process 503 at a ratio of, for example, 8 to 2 in a mass ratio, and the blended (mixed coal) coal is manufactured as a cement-using facility through a transport process 504 such as a belt conveyor. It is carried out by transporting to the facility 600 or the coal-fired power generation facility 700. As shown in FIG. 11, the transported coal is configured to be used as fuel in the firing process 601 of the cement manufacturing facility 600 and the boiler process 701 of the coal-fired power generation facility 700.

JP-A-10-281443

  However, in the conventional drying facility disclosed in Patent Document 1 described above, drying with high thermal efficiency is realized in the coal-fired power generation facility, but it is not always efficient due to fluctuations in operating conditions in the power generation facility. The process has not been completed.

  In addition, with soaring coal prices in recent years and the expansion of global energy demand, so-called high-grade coals such as bituminous coal tend to have lower reserves and higher prices. There is a demand to use a lot of low-grade coal with high environmental efficiency and good utilization efficiency.

  Furthermore, for example, in a conventional drying facility, exhaust gas containing pulverized coal after drying treatment is discharged through an electric dust collector and a desulfurization device or the like, or pulverized coal is removed by discharging it through a wet process. However, in the former case, pulverized coal that could not be completely removed may be discharged with high-temperature exhaust gas, which may cause environmental impact or cause ignition. Can not wipe. In the latter case, the pulverized coal removed from the exhaust gas is moistened. Therefore, when the pulverized coal is recovered and reused, it is necessary to perform a drying process again. There is a problem that it is difficult to prevent the expansion of energy loss.

  Further, for example, when the low-grade coal transported from the coal accumulation relay facility 500 described above is dried and only the dried low-grade coal is sent to the fuel combustion boiler (boiler process 701) of the coal-fired power generation facility 700, Before it burns the coal after blending with high-grade coal (mixed coal) in the coal-fired power generation facility 700, it may pollute the surrounding environment by generating dust (generating dust). When trying to dry, there is a problem that the amount of dry processing increases and efficiency decreases.

  In addition, in conventional drying equipment, for example, high-grade coal and low-grade coal that has been subjected to drying treatment are mixed and used as fuel for coal-fired power generation equipment, but various low-grade coals are used under uniform and constant conditions. Since the coal is dried together, for example, when the total moisture content of the low-grade coal varies depending on conditions, the total moisture content of the coal brought into the coal-fired boiler (fuel combustion boiler) may vary. is there. In addition, depending on the type of coal, the amount of moisture that can be dried is small, and the difference in total moisture before and after drying may be small.

  In this case, the conditions for drying the low-grade coal (for example, the amount of heat required for drying and the drying time) and the operating conditions for the coal-fired power generation facility (for example, the operating time and the amount of fuel supplied) vary frequently. Need to be made. For this reason, stable operation of the coal-fired power generation facility becomes difficult, and there is a problem that an increase in cost and an increase in equipment are unavoidable, resulting in an inevitable increase in cost.

The present invention has been made to solve such problems, and in particular, low-grade coal is efficiently dried at low cost and efficiently in an environmentally good state, and is effectively used in a coal utilization facility. It is an object of the present invention to provide a method and a system for treating coal.
In addition, the present invention can reduce the total water content of coal mixed with low-grade coal and high-grade coal, and thus can improve the thermal efficiency when burning in coal-utilizing facilities, To provide a coal processing method and a processing system capable of improving the utilization rate of low-grade coal while minimizing the influence on the environment such as dust generated from the low-grade coal during transportation. With the goal.
In addition, the present invention aims to stabilize the quality of coal blended coal that is brought into the coal-fired power generation facility and reduce the total water content, improve the combustion efficiency and improve the thermal efficiency, It is an object of the present invention to provide a coal processing method and a processing system capable of reducing the amount of heat required for drying while stabilizing the operating conditions of a power generation facility so that the coal utilization facility can be operated at a low cost.

  The method for treating coal according to the present invention is a method for treating coal in which coal is dried and burned in a coal-fired power generation facility, and the interior is partitioned into an upper drying chamber and a lower gas chamber by a gas dispersion plate, A paddle shaft horizontally mounted is rotatably provided, and a plurality of paddles for agitating coal at intervals in the axial direction of the paddle shaft are mounted in the drying chamber of the paddle stirring dryer. Then, hot gas is supplied into the gas chamber from a hot gas supply facility different from the coal thermal power generation facility to dry the coal.

  Moreover, you may provide the process of blending the dried dry coal with unprocessed coal other than the dry coal, and the process of sending coal blended coal to the coal thermal power generation equipment.

  Furthermore, you may provide the process of mixing other gas with the exhaust gas containing the pulverized coal discharged | emitted from drying equipment, and cooling the exhaust gas containing the said pulverized coal.

  In addition, the method includes a step of determining whether or not the coal needs to be dried before drying the coal, and the determination of whether or not the drying treatment is necessary is based on information on the total moisture and equilibrium moisture of the coal before drying. The coal to be treated having a predetermined property that has been determined to require drying may be dried to a predetermined state.

  The hot gas supply facility is preferably a cement manufacturing facility. As the hot gas discharged from the cement manufacturing facility, exhaust gas having a heat of about 400 ° C. discharged from a preheating device such as a suspension preheater in the firing process, or about a heat discharged from a cooling device such as a clinker cooler in the cooling process. There is an exhaust gas having a heat of 300 ° C. Among these, the exhaust gas discharged from the firing process has a low oxygen concentration of about several percent, and can be said to be preferable as a heat source to be supplied to the coal drying process from the viewpoint of safety. However, in many cement manufacturing facilities, the heat (exhaust heat) of the hot gas (exhaust gas) discharged from the firing process is already used for drying air, exhaust heat recovery power generation, etc. in the pulverization process. Therefore, the hot gas is preferably exhaust heat that is not used in the cement manufacturing facility, for example, hot gas discharged from the clinker cooler that is a cooling step (exhaust gas of the clinker cooler).

  Moreover, it is preferable to dry coal so that the temperature of coal after drying may be 70 degrees C or less. The mixed coal is preferably performed by supplying the dry coal to a transportation means for transporting the untreated coal. The other gas mixed with the exhaust gas after the drying treatment is preferably air at ambient temperature. The exhaust gas is preferably cooled to a temperature of 75 ° C. or lower. It is preferable that the exhaust gas containing pulverized coal and a mixed gas composed of another gas further include a step of separating the pulverized coal.

  The determination of whether or not the drying treatment is necessary is preferably performed based on information on the total moisture and equilibrium moisture of the coal. In addition, the determination of whether or not the drying treatment is necessary is performed when the numerical value obtained by subtracting the equilibrium moisture from the total moisture of the coal is 8 or more, and the drying treatment is determined to be necessary. It is preferably performed by determining that the drying process is unnecessary. It is preferable that the coal to be treated is obtained by reforming coal and molding and processing it into pellets and / or briquettes. The drying treatment is preferably performed so that the total moisture of the coal after the drying treatment exceeds the equilibrium moisture.

  The energy required to remove coal adhering moisture is about the latent heat of vaporization of water, while the removal of moisture inside particles (crystal water and internal water) other than adhering moisture requires more energy than removal of adhering moisture. Cost. Therefore, coal to be treated which is a drying target is preferably coal with a large amount of attached moisture. Since coal with a large amount of moisture adheres can reduce the amount of moisture reduction, it is possible to increase the merit of the drying operation, that is, the amount of increase in calorific value. Therefore, the coal to be treated is preferably low-grade coal such as subbituminous coal or lignite with a large amount of adhering moisture. On the other hand, high-grade coal such as bituminous coal has less adhesion moisture, and the merit of drying operation is small. Therefore, bituminous coal and the like are blended (blended coal) with dry coal as untreated coal.

  The method for treating coal according to the present invention is a process characterized by blending (mixing) dry coal obtained by drying the coal to be treated and untreated coal other than the dry coal. On the other hand, in the case of the process of drying after blending the coal to be treated and the untreated coal in advance, the drying merit is reduced, and in addition, the amount of drying treatment is increased, and the dryer and incidental equipment are Since it enlarges, it is not preferable. For this reason, compared with the latter process, the amount of drying treatment can be reduced, and the enlargement of a dryer and incidental equipment can be avoided.

  In addition, the blend (mixed coal) ratio by the mass ratio of the dried dry coal and the untreated coal other than the dry coal is 8 to 2 to 2 to 8, preferably 8 to 2 to 3 to 7, and particularly preferably 7 It is good to set in the range of the pair 3 to 5 to 5. If the mass ratio of the dry coal in the coal after blending (mixed coal) exceeds 8, the mass of the coal after blending (mixed coal) and the mass (the same mass) will be obtained, and it is more efficient to dry after blending (mixed coal). It is not preferable. In addition, if the mass ratio of the dry coal is less than 2, it is not preferable because the amount of increase in the amount of heat generated by drying becomes small.

  Further, the coal treatment system according to the present invention is a coal treatment system for drying coal and combusting it in a coal-fired power generation facility, wherein the interior is partitioned into an upper drying chamber and a lower gas chamber by a gas dispersion plate, The drying chamber of a paddle agitation dryer in which a horizontal paddle shaft is rotatably provided in the drying chamber, and a plurality of paddles for agitating coal are attached at intervals in the axial direction of the paddle shaft. Is provided with a supply port for supplying coal, the gas chamber is provided with a hot gas supply port for supplying hot gas for drying the coal, and the clinker cooler of the hot gas supply port and cement manufacturing facility It is characterized by being connected to an exhaust gas exhaust line.

  The coal processing system according to the present invention includes a coal accumulation relay facility, a coal-fired power generation facility, a coal drying treatment facility, and a cement production facility, and the coal accumulation relay facility has a plurality of types of different properties. Before the coal is burned and used in the coal-fired power generation facility, the coal to be treated having a predetermined property of the coal is heated using the hot gas from the cement manufacturing facility. It is characterized by being configured to dry the dried coal so as to be in a predetermined state, and mix the dried coal with untreated coal other than the dried coal and send it to the coal-fired power generation facility.

  The coal treatment system according to the present invention includes a coal-fired power generation facility, a coal drying treatment facility, and a cement manufacturing facility, and before the coal-fired power generation facility burns and uses a plurality of types of coal having different properties. Introducing hot gas from the cement production facility in the coal drying treatment facility to dry the treated coal having a predetermined property of the coal so as to be in a predetermined state and occurring during drying It is also possible to cool the exhaust gas mixed with other gases.

  Furthermore, a coal accumulation relay facility, a coal thermal power generation facility, a coal drying treatment facility, and a cement production facility are provided, and before the coal is burned and used in the coal thermal power generation facility, a plurality of types are collected from the coal accumulation relay facility. The coal having different properties is transported to the coal drying processing facility, the hot gas from the cement manufacturing facility is introduced in the coal drying processing facility, and the coal to be treated having a predetermined property of the coal is predetermined. While drying so that it may be in a state, the dried dry coal can also be blended (blended coal) with unprocessed coal other than this dry coal, and can be sent to the coal thermal power generation equipment.

  The coal drying processing facility is divided into an upper drying chamber and a lower gas chamber by, for example, a gas dispersion plate, and a horizontal paddle shaft is rotatably provided in the drying chamber. It is preferable that the paddle stirring dryer is provided with a plurality of paddles for stirring coal at intervals in the direction.

  The coal treatment system according to the present invention includes a coal-fired power generation facility, a coal drying treatment facility, and a cement manufacturing facility, and before the coal-fired power generation facility burns and uses a plurality of types of coal having different properties. Determining whether or not the coal drying treatment is necessary in the coal drying treatment facility, and introducing hot gas from the cement manufacturing facility based on the determination result of whether or not the drying treatment is necessary. The coal to be treated having a predetermined property determined to require the drying process is dried so as to be in a predetermined state.

According to the present invention, a method and a process for treating coal, in which low-grade coal is dried in a low-cost and efficient manner, particularly in an environmentally good state, and can be effectively used in a coal-fired power generation facility. A system can be provided.
In addition, according to the present invention, it is possible to reduce the total water content of coal in which low-grade coal and high-grade coal are blended (mixed coal), so that it is possible to improve thermal efficiency when burning in coal-fired power generation equipment. It is possible to reduce the influence on the environment such as dust generated from the low-grade coal during transportation, and to improve the utilization rate of the low-grade coal.
Furthermore, it is possible to stably operate the coal-fired power generation facility by preventing the influence of the exhaust gas discharged during drying on the environment and the possibility of ignition.
In addition, according to the present invention, it is possible to stabilize the quality of coal mixed into the coal-fired power generation facility and reduce the total water content, achieve improvement in combustion efficiency and increase thermal efficiency, While stabilizing the operating conditions of the coal-fired power generation facility, the amount of heat required for drying can be reduced, and the coal-fired power generation facility can be operated at low cost.

It is a block diagram which shows an example of the whole outline | summary of the coal processing system which implement | achieves the coal processing method which concerns on the 1st Embodiment of this invention. It is explanatory drawing for demonstrating an example of the coal drying processing equipment of the processing system. It is a block diagram which shows an example of the whole flow of the coal processing system which implement | achieves the coal processing method which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows an example of the whole outline | summary of the processing system of the coal. It is explanatory drawing for demonstrating an example of the coal drying processing equipment of the coal processing system which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows an example of the whole flow of the processing method and processing system of coal which concern on the 3rd Embodiment of this invention. It is a block diagram which shows an example of the whole outline | summary of the processing system of the coal. It is explanatory drawing for demonstrating an example of the coal drying processing equipment of the processing system of the coal. It is a block diagram which shows an example of the whole flow of the processing method and the processing system of coal which concern on the 4th Embodiment of this invention. It is a block diagram which shows an example of the whole outline | summary of the processing system of the coal. It is a block diagram which shows an example of the whole flow of the conventional coal processing system.

  Hereinafter, preferred embodiments of a coal processing method and a processing system according to the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a block diagram showing an example of an overall outline of a coal processing system that realizes the coal processing method according to the first embodiment of the present invention. As shown in FIG. 1, the coal processing system 1 includes a coal-fired power generation facility 100, a cement manufacturing facility 200 that is a hot gas supply facility, and a coal drying processing facility 300.

  The coal-fired power generation facility 100 is a facility that generates power by burning and using coals having different types of properties, and includes a power generation process similar to the power generation process of a known coal-fired power generation facility. That is, in the coal-fired power generation facility 100, first, supplied coal is pulverized to a predetermined size in a pulverization process 102 using a vertical pulverizer and the like, and in a boiler process 103, about 1600 is obtained by a pulverized coal combustion boiler. Burns at a temperature of ° C.

  Then, the steam turbine is driven in the power generation process 104 by the heat energy generated in the boiler process 103 to supply electric power. In the feed water heating step 105, the feed water to the fuel combustion boiler is heated by using the extraction air from the steam turbine by the feed water heater to improve the thermal efficiency in the power generation step 104.

  On the other hand, the exhaust heat (exhaust) gas generated in the boiler process 103 is removed of nitrogen oxides in a denitration process 106 using a flue gas denitration apparatus or the like, and further in a heat recovery process 107 using a gas air heater or the like. Dust is collected in a dust collection step 108 using an electric dust collector or the like that collects dust floating in the exhaust heat gas after being used to warm the combustion air pressure-fed to step 103.

  Thereafter, the exhaust heat gas is discharged into the atmosphere as an exhaust gas after the sulfur oxide is removed in a desulfurization step 109 using a flue gas desulfurization apparatus or the like. In this way, power generation is performed in the coal-fired power generation facility 100 in the coal processing system 1 according to the first embodiment.

  In the present processing system 1, the coal is dried by the coal drying processing facility 300 before being supplied to the crushing process 102. Examples of the coal to be dried include low-grade coals such as subbituminous coal and lignite. The coal is dried to a predetermined moisture.

The predetermined moisture is moisture that is as low as possible and does not fall below the equilibrium moisture of the coal. Equilibrium moisture here refers to moisture that is in an equilibrium state in an atmosphere (dryer outlet, storage silo, air) to which coal is exposed in the course of use.
Since the heat generation can be increased by removing the moisture of the coal, it is desirable that the moisture of the dry coal be as low as possible. However, when the moisture of the dry coal discharged from the coal drying processing facility 300 is lower than the equilibrium moisture in the atmosphere, the dry coal absorbs moisture in the atmosphere.

  Therefore, the reason why the moisture does not fall below the predetermined equilibrium moisture is to prevent re-absorption of the dry coal and also to ensure the drying efficiency. The moisture not lower than the equilibrium moisture is equal to or higher than the equilibrium moisture of coal and 1.3 times or less of the equilibrium moisture, preferably equal to or higher than the equilibrium moisture and not more than 1.2 times the equilibrium moisture. For example, when drying subbituminous coal with a total water content of 25% by weight and an equilibrium water content of 15% by weight, the lowest possible water content, for example 15% to 19.5%, is avoided while avoiding the predetermined water content below 15% by weight. % By weight, preferably 15 to 18% by weight. In addition, the water | moisture content which is not less than predetermined equilibrium water | moisture content changes with kinds of coal. Accordingly, drying conditions of the drying equipment such as the supply amount of coal, the temperature of the dry hot gas, the supply amount of the dry hot gas, and the rotational speed of the paddle are appropriately set according to the total moisture of the coal.

  The total moisture was measured in accordance with JIS M8820 (coal and coke-lot total moisture measurement method). The equilibrium moisture content can be obtained by measuring the dry coal according to, for example, JIS A1475 (method for measuring the equilibrium moisture content of building materials) to obtain an equilibrium moisture content curve of the dry coal. The equilibrium moisture content of the dry coal is obtained from the equilibrium moisture content curve obtained here and the temperature and relative humidity data in each atmosphere (dryer outlet, storage silo, and air) exposed in the course of use of the dry coal. Since the obtained equilibrium moisture content is the percentage of water mass based on the total mass after drying, the equilibrium moisture content of the dry coal is obtained by converting to the percentage of water mass based on the total mass before drying by the following equation (1). Can do.

  In the present processing system 1, the waste heat energy in the cement manufacturing facility 200 is used for the coal drying processing facility 300. That is, the cement manufacturing facility 200 is configured to include a manufacturing process similar to that of a known cement manufacturing facility, and in this manufacturing process, raw materials such as limestone, clay, silica, and iron raw materials are pulverized. After being pulverized in the used pulverization step 201, the calcination step 202 is calcinated at a temperature of about 1450 ° C. using a calcination furnace using coal as a fuel to obtain a cement clinker. Thereafter, the cement clinker fired in the cooling step 203 using a clinker cooler or the like is cooled, mixed and pulverized with gypsum and other mixed materials in the finishing step 204, and finished as powdered cement.

  In such a manufacturing process, particularly in the cooling process 203, exhaust gas having a heat of about 300 ° C. is exhausted from a clinker cooler or the like, but the exhaust heat of this exhaust gas was exhausted without being used as it is. Is the current situation. Therefore, the present processing system 1 can use the exhaust heat of the exhaust gas for the coal drying process in the coal drying processing facility 300 without almost modifying existing facilities.

  As a result, energy saving in the use of coal can be promoted and fuel unit consumption can be improved, and treated coal such as low-grade coal with a high recoverable reserve and low cost can be used in the same way as high-grade coal. It will be possible to extend the life of coal resources.

  Here, the coal drying processing facility 300 that realizes the above-described coal drying processing will be described. FIG. 2 is an explanatory diagram for explaining an example of the coal drying processing facility 300 of the coal processing system 1 according to the first embodiment of the present invention. In the following description, parts that are the same as those already described are denoted by the same reference numerals, description thereof is omitted, and parts not particularly relevant to the present invention may not be specified.

  First, for example, high-grade coal or low-grade coal is supplied from the existing coal transmission line 2 to the bifurcated damper 3, and in this bifurcated damper 3, for example, high-grade coal is distributed to the existing coal delivery line 4 side, and low grade coal is also produced. Treated coal such as charcoal is distributed to the existing coal transmission line 5 side.

  The sorting by the bifurcated damper 3 is performed, for example, by the control device 7 controlling the bifurcated damper 3 based on the information of the measured total moisture of the coal from the moisture meter 6 installed in the existing coal feeding line 2. Processed coal such as low-grade coal distributed to the existing coal transmission line 5 side is input to the receiving silo 9.

  The to-be-processed coal thrown into the receiving silo 9 is extracted from the receiving silo 9 by the extraction conveyor 12 and conveyed to the screw feeder 14 via the vertical conveyor 13. The treated coal transported to the screw feeder 14 is fed into the dryer 20 through the rotary valve 15.

The dryer 20 is a known paddle stirring dryer that dries the coal to be treated on the gas (air) dispersion plate 22 with a paddle 21, for example, and the coal to be treated (dry coal) that has been stirred and dried is Then, it is carried out of the dryer 20 by the discharge conveyor 17 through the rotary valve 16. In this example, it is preferable to dry the coal so that the temperature of the dried coal is 70 ° C. or lower. Thereby, the possibility that dry coal will ignite can be suppressed effectively. For this purpose, drying conditions of the drying equipment such as the supply amount of coal, the temperature of the drying hot gas, the supply amount of the drying hot gas, and the rotational speed of the paddle are set as appropriate. It is also preferable to monitor the temperature in the dryer.
The exhaust from the dryer 20 is sent to the bag filter 19 by the exhaust fan 18, and after dust is removed by the bag filter 19, the exhaust is discharged from the exhaust duct 31 to the atmosphere by the bag filter fan 30.

  The dryer 20 is divided into an upper drying chamber and a lower air chamber by a gas (air) dispersion plate 22, and a number of slit-shaped openings are provided in parallel on the gas (air) dispersion plate 22. A paddle shaft horizontally mounted in the drying chamber is provided at a variable speed. A plurality of paddles 21 for stirring the coal to be treated are attached to the paddle shafts at intervals in the axial direction of the paddle shafts. The paddles 21 have the mounting angles in the axial direction of the paddles 21 adjacent to each other in the paddle axial direction. It is installed with the phase shifted. The amount of coal remaining in the drying chamber is adjusted by the paddle rotation speed, the paddle scraping area, the attachment position and shape of the discharge port, and the like. The bulk volume occupied by the coal staying in the drying chamber is a ratio of 20% to 30% by volume (holdup rate) with respect to the reachable cylinder volume of the paddle, that is, 100% by volume of the paddle stirring volume. It is preferable.

  The paddle 21 itself is attached to the paddle shaft in such a manner that the treated coal is inclined with respect to the axis of the paddle shaft so as to apply the axial stirring force to the treated coal and the inclination angle thereof is adjustable, and one end of the paddle shaft of the drying chamber is attached. A supply port and a discharge port for the coal to be treated are provided on the side and the other end, respectively, and a dry hot gas is introduced into the air chamber, and the dry hot gas is fed through the slit-shaped opening of the gas (air) dispersion plate 22 Then, the coal to be treated is fluidized by being injected into the drying chamber.

  For example, it is fluidized by a dry hot gas of about 100 ° C., the paddle 21 is rotated by the rotation of the paddle shaft, the coal to be treated is scraped up, and the particles are agitated well. On the other hand, the paddle 21 is attached while being inclined and is dried while being moved in the paddle axial direction.

  The dry coal transported from the dryer 20 is input from the discharge conveyor 17 to the product silo 34 via the vertical conveyor 33. Note that dust (pulverized coal) collected by the bag filter 19 is also introduced into the product silo 34 by a dust (pulverized coal) transport system 35.

  The product coal including the dry coal is supplied from the product silo 34 to the vertical conveyor 38 by the transport conveyor 37 having the quantitative supply and metering system 36, and is sent to the existing main coal feed line 39. It is mixed (mixed) with high-grade coal, sent to the pulverization process 102 of the coal-fired power generation facility 100, and used as fuel for the pulverized coal combustion boiler in the boiler process 103. Specific examples of the coal blending method include a method of supplying dry coal to bituminous coal transported by a belt conveyor, a method of supplying dry coal to a joint portion of a belt conveyor for transporting bituminous coal, such as a chute portion, and the like. Bituminous coal and dry coal are blended by repeatedly moving, dropping and rolling on the transported belt conveyor.

In the coal drying processing facility 300, exhaust gas including exhaust heat discharged from a clinker cooler or the like in the cooling step 203 of the cement manufacturing facility 200 described above is supplied during the drying processing of the coal to be processed in the dryer 20. Used.
In addition, low-grade coal is highly pyrophoric, and there is a risk that low-grade coal may ignite in the dryer due to drying. For this reason, nitrogen gas, plant air such as the atmosphere, tap water (industrial water), and the like are used as safety measures against ignition in the dryer 20.

  This exhaust gas contains thermal energy that has been discarded almost without being used even when the temperature is about 300 ° C. when discharged from a clinker cooler or the like. In the dryer 20 of the facility 300, even when the temperature is lowered to about 80 ° C. to about 200 ° C. when the dryer is introduced into the dryer 20, it is used for drying treatment of coal to be treated. And by the drying process by this dryer 20, the to-be-processed coal is dried so that it may become predetermined | prescribed moisture.

(Example of the first embodiment)
Hereinafter, the present invention will be described in detail by way of examples and comparative examples of the first embodiment.
The dryer used for the Example and the comparative example used the paddle stirring type dryer which has the structure equivalent to the said dryer 20, and it implemented on the following conditions.

  The dryer used has a cylindrical drying chamber with an inner dimension of φ268 mm × 740 mm, and a φ140 mm treated portion is located directly above the side wall on the treated coal supply port side in the drying chamber at a position 50 mm away in the paddle axis direction. 140 mm × 140 mm treated coal on the side wall (position of horizontal reference angle 5 ° to 75 °) at a position 495 mm away from the side wall on the treated coal supply port side in the drying chamber in the paddle axis direction It has a semicircular discharge port for discharging gas, and has a structure that discharges exhaust gas dust-removed by a cyclone from the exhaust gas line above the discharge port to the atmosphere.

The gas (air) dispersion plate between the drying chamber and the air chamber is provided with 3 mm × 140 mm slit openings at 45 mm intervals, and a 75 mm × 75 mm paddle is seen in the axial direction on a paddle shaft with a shaft diameter of φ76.3. The paddle shaft attached to the paddle shaft at 90 mm intervals with the mounting angles of 120 ° shifted from each other is horizontally mounted in the drying chamber, and a screw feeder for supplying the coal to be processed is provided above the coal supply port to be processed. .
In addition, in order to evaluate the safety of the dryer, analysis of exhaust gas from which dust was removed and the temperature of dry coal were measured.

  The properties of the coal to be treated (subbituminous coal) used in Examples and Comparative Examples are shown in Table 1 below. The total moisture was measured according to JIS M8820 (coal and coke-lot total moisture measurement method). The industrial analysis was measured in accordance with JIS M8812 (coal and coke-industrial analysis method). The calorific value was measured in accordance with JIS M8814 (coal and coke-bomb calorimeter measuring method of total calorific value and true calorific value calculating method). The particle size distribution was measured according to JIS M8801 (Coals-Test method).

  Table 2 below shows the equilibrium moisture content of the coal to be treated (sub-bituminous coal) used in Examples and Comparative Examples. The equilibrium moisture content is the equilibrium moisture content of the treated coal obtained according to the desiccator method (measurement temperature: 20 ° C. to 50 ° C., relative humidity: 10% to 98%) of JIS A1475 (equilibrium moisture content measurement method for building materials). Based on the rate data, create a correlation formula to find the equilibrium moisture from the temperature and relative humidity, using the temperature and relative humidity in the atmospheric conditions (dryer outlet and air) in which the examples and comparative examples were implemented in the same formula, The equilibrium moisture content of the dry coal was determined and calculated from the determined equilibrium moisture content according to the formula (1).

The drying heat source of the dryer was set so that the clinker cooler exhaust gas of the cement production facility was adjusted to about 80 ° C. to about 180 ° C. with air, and the flow rate was set to 150 Nm ³ / h. The residence time was set to be about 180 seconds by adjusting the rotation speed of the paddle.

  The results of tests conducted under the above conditions are shown in Table 3 below. Note that the effective volume used for calculating the heat capacity coefficient is the portion corresponding to the distance from the first slit of the gas dispersion plate to the discharge port in the volume of the drying chamber in which the coal stays. It was determined using a distance from 45 mm to 495 mm in the paddle axis direction from the side wall on the treated coal supply port side.

Hereinafter, examples and comparative examples will be described.
Example 1
As a result of conducting the test with a coal supply rate of 20.4 kg / h and a drying heat source temperature of 82 ° C., the total coal moisture was 32.5% by mass at the time of supply, but after drying it was 20.3% by mass. The heat capacity coefficient was 5612 kcal / m ³ hr ° C. Moreover, the coal temperature at this time was 19.9 degreeC.
(Example 2)
As a result of carrying out the test with a coal supply rate of 20.0 kg / h and a drying heat source temperature of 121 ° C., the total water content of coal was 33.1% by mass at the time of supply, but 19.0% by mass after drying. The heat capacity coefficient was 5236 kcal / m ³ hr ° C. Moreover, the coal temperature at this time was 25.3 degreeC.
(Example 3)
As a result of conducting the test with a coal supply rate of 40.1 kg / h and a drying heat source temperature of 180 ° C., the total coal moisture was 32.4% by mass at the time of supply, but 18.4% by mass after drying. The heat capacity coefficient was 5020 kcal / m ³ hr ° C. Moreover, the coal temperature at this time was 40.1 degreeC.
(Comparative example)
As a result of conducting the test with a coal supply rate of 20.3 kg / h and a drying heat source temperature of 180 ° C., the total water content of coal was 32.9% by mass at the time of supply, but 12.1% by mass after drying. The heat capacity coefficient was 2747 kcal / m ³ hr ° C. Moreover, the coal temperature at this time was 79.0 degreeC.

  As in Examples 1 to 3, by appropriately controlling the supply amount of the coal to be treated and the drying gas temperature, the coal to be treated is changed from the total moisture (about 32.8% by mass) to a predetermined moisture, that is, the equilibrium of the coal to be treated. It has been found that it is possible to dry to below the moisture (17.6% by mass) and to the lowest possible moisture. Moreover, in the existing coal-fired power generation facility, in order to prevent the ignition of coal in the pulverized coal mill, the temperature in the mill is controlled to 70 ° C. or less. The coal temperature observed in Examples 1 to 3 was lower than the control temperature, and it was confirmed that there was no safety problem.

  On the other hand, in the comparative example, the moisture of the dry coal was much lower than the equilibrium moisture, so that the moisture was absorbed again after drying. Since moisture absorption after drying leads to loss of drying energy, it is not preferable as an operating condition. Moreover, since the temperature of dry coal exceeds the pulverized coal mill management temperature (70 degreeC) of coal-fired power generation equipment, it cannot be said that it is a preferable method as an operating condition also in terms of safety.

  As a result of the above, the total water content of the coal is obtained by a drying heat source of about 80 ° C. to about 180 ° C. in a lower temperature range than the assumed temperature of about 200 ° C. to about 300 ° C. of the clinker cooler exhaust gas discharged from the cooling step 203 described above. It has been found that it is possible to reduce to a predetermined moisture.

  As described above, reducing the total moisture of the coal to be treated to a predetermined moisture (moisture exceeding the equilibrium moisture) using low level heat (for example, about 80 ° C. to about 180 ° C.) as a heat source has no safety problem. According to the processing system 1 according to the first embodiment, the thermal energy discharged from the cement manufacturing facility 200 is used in the coal-fired power generation facility 100, and the quality equivalent to that of a high-grade coal such as bituminous coal is used. It can be dried and effectively used as fuel.

  As described above, according to the method and system for treating coal according to the first embodiment, it is possible to use low-grade coal by reforming it to a quality equivalent to high-grade coal using existing equipment. Therefore, it is possible to expand the use of low-grade coal and enable effective use of resources.

  In addition, the treated coal (dry coal) after drying treatment has low possibility of ignition, is easy to handle and can be handled in the same way as high-grade coal, and exhaust heat of exhaust gas emitted from cement production Can be used as the energy for the drying treatment, so that it is possible to save energy through effective use of thermal energy in an environmentally favorable state, and to promote cost reduction of coal use.

(Second Embodiment)
FIG. 3 is a block diagram showing an example of the overall flow of a coal processing system that realizes the coal processing method according to the second embodiment of the present invention, and FIG. 4 shows an example of the overall outline of the coal processing system. FIG. As shown in FIGS. 3 and 4, the coal processing system 1A includes a coal-fired power generation facility 100, a cement manufacturing facility 200 that is a hot gas supply facility, a coal drying processing facility 300, the coal-fired power generation facility 100, A coal accumulation relay facility (call center) 400 that accumulates and relays coal used as fuel in the cement manufacturing facility 200 is provided.

  In the present processing system 1A, as shown in FIG. 3, for example, high-grade coal such as bituminous coal 401 collected in the coal accumulation relay facility 400 and treated coal 402 that is low-grade coal such as sub-bituminous coal and lignite coal, Are transported to the coal drying treatment facility 300 by separate routes. That is, bituminous coal 401 is carried by a transporting process 208 such as a belt conveyor, and the coal to be treated 402 is sent to a drying process 209 by another belt conveyor or the like.

  In the drying process 209 of the coal drying processing facility 300, exhaust heat from the cooling process 203 of the cement manufacturing facility 200 is introduced, and the drying process of the coal 402 to be treated is performed. The coal is blended with bituminous coal 401 in the belt on the transportation line that continues from the transportation step 208, that is, the transportation / mixing step 210, and then the boiler (combustion) step 110 of the coal-fired power generation facility 100 as coal for fuel. Used as fuel.

  The processing system 1A configured as described above will be further described. As shown in FIG. 4, the coal-fired power generation facility 100 is mixed with a plurality of types of coal having different properties as described in the first embodiment. This is a facility for generating electricity by using a mixture of coal, and comprises a power generation process similar to that of a known coal-fired power generation facility. The coal-fired power generation of the processing system 1 in the first embodiment described above It has the same configuration and process as the equipment 100. Therefore, in the coal-fired power generation facility 100, first, the coal blend supplied from the coal drying processing facility 300 is pulverized to a predetermined size in the pulverization step 102 using a vertical pulverizer or the like. The subsequent boiler process (equivalent to the combustion process 110) 103, power generation process 104, feed water heating process 105, denitration process 106, heat recovery process 107, dust collection process 108, and desulfurization process 109 are as described above. The coal-fired power generation facility 100 in the coal processing system 1A according to the second embodiment generates electric power through these steps.

  In the present processing system 1 </ b> A, the coal to be processed 402 is dried by the coal drying processing facility 300 before being supplied to the pulverization process 102. Examples of the coal to be treated 402 dried here include low-grade coals such as subbituminous coal and lignite. Among these, low-grade coal that contains a lot of moisture and is inexpensive is preferably used. The coal 402 to be treated is dried so as to have the above-described predetermined moisture content.

  Here, the predetermined moisture, the equilibrium moisture, the moisture that does not fall below the equilibrium moisture, and the total moisture are as described in the first embodiment. Therefore, the description is omitted here, and the drying conditions of the drying equipment are the coal to be treated. It is set as appropriate according to the total water content and the equilibrium water content in the atmosphere. Moreover, the equilibrium water | moisture content of dry coal can be similarly calculated | required by said Formula (1).

  Note that, in the coal-fired power generation facility 100 according to the second embodiment, unlike the bituminous coal called so-called high-grade coal among the coals having different properties depending on the coal drying treatment facility 300, the coal-fired power generation facility 100 has a low water content and is inexpensive. Coal coal blended with high-grade coal is used as fuel after subjecting coal to be treated with specified properties, including sub-bituminous coal and lignite, which are high-grade coal, to a state as described above in advance. . In the present processing system 1A, the waste heat energy in the cement manufacturing facility 200 is transported in the coal drying processing facility 300, not in the coal thermal power generation facility 100, in the transportation / mixing process 210 including the coal drying processing (drying step 209). It is done using.

  The configuration, operation, manufacturing process, and the like of the cement manufacturing facility 200 are as described above. In such a manufacturing process, particularly in the cooling process 203, exhaust gas having a heat of about 300 ° C. is exhausted from a clinker cooler or the like, but the exhaust heat of this exhaust gas was exhausted without being used as it is. Is the current situation. Therefore, the present processing system 1A can utilize the exhaust heat of the exhaust gas for the coal drying process in the drying step 212 of the coal 402 to be processed in the coal drying processing facility 300 without almost modifying the existing facilities. It is configured.

  For example, the bituminous coal 401 is transported as it is from the coal accumulation relay facility 400 to the coal drying treatment facility 300 through the transportation step 208, and the treated coal 402 is cooled in the drying step 209 in the cooling step of the cement manufacturing facility 200. The coal drying process using the heat energy of the exhaust heat at 203 is performed. Then, the dried coal is mixed with bituminous coal 401 transported in the transport / mixing step 210 and then sent to the coal-fired power generation facility 100. Specific examples of the coal blending method include a method of supplying dry coal to bituminous coal transported by a belt conveyor, a method of supplying dry coal to a joint portion of a belt conveyor for transporting bituminous coal, such as a chute portion, and the like. Bituminous coal and dry coal are blended by repeatedly moving, dropping and rolling on the transported belt conveyor.

  As a result, as in the first embodiment, energy saving in the use of coal can be promoted to improve the fuel intensity, and the coal to be treated such as low-grade coal that has a large recoverable reserve and is inexpensive. Can be used in the same way as high-grade coal, and it is possible to extend the life of coal resources.

  Here, the coal drying processing facility 300 that realizes the transport / mixing process 210 including the drying process of the coal to be processed 402 in the drying process 209 described above will be described. FIG. 5 is an explanatory diagram for explaining an example of the coal drying processing facility 300 of the coal processing system 1A according to the second embodiment of the present invention.

  As shown in FIG. 5, first, low-grade coal is supplied to the bifurcated damper 3 from the existing coal line 2 that continues from the coal accumulation relay facility 400, and in this bifurcated damper 3, for example, low-grade coal that is not subjected to drying treatment is supplied. While being distributed to the existing coal transmission line 4 side, the coal to be treated which is a low-grade coal to be dried is distributed to the existing coal transmission line 5 side.

The distribution by the bifurcated damper 3 is performed by the control device 7 controlling the bifurcated damper 3 based on the information on the total moisture of the low-grade coal measured from the moisture meter 6 installed in the existing coal line 2, for example. Done.
The low-grade coal distributed to the existing coal transmission line 4 side, for example, has too much moisture or is of a quality that does not deserve processing, and is sent back to the coal accumulation relay facility 400, for other purposes. It is used for.

  The treated coal distributed to the existing coal transmission line 5 side is input to the receiving silo 9. The to-be-processed coal thrown into the receiving silo 9 is extracted from the receiving silo 9 by the extraction conveyor 12 and conveyed to the screw feeder 14 via the vertical conveyor 13. The treated coal transported to the screw feeder 14 is fed into the dryer 20 through the rotary valve 15.

  The dryer 20 is composed of, for example, the above-described known paddle stirring dryer, has the configuration and operation described in the first embodiment, and operates in the same manner. The coal to be treated is ejected from the air chamber through the gas (air) dispersion plate 22 into the drying chamber. The dry coal transported from the dryer 20 is fed into the product silo 34 from the discharge conveyor 17 through the vertical conveyor 33, and a predetermined amount is transferred from the product silo 34 to the vertical conveyor 38 by the transport conveyor 37 having the quantitative supply and metering system 36. They are supplied one by one and blended by being dropped onto the high-grade coal (bituminous coal) that has been transported on the existing main coal feeding line 39 in the transportation step 208. This part corresponds to the transportation / mixing process 210 described above. Thus, the blended blend of bituminous coal and dry coal is sent to the pulverization step 102 of the coal-fired power generation facility 100 and used as fuel for the fuel combustion boiler in the boiler step 103.

  In addition, the ratio of the blended coal by the mass ratio of the dry coal and the bituminous coal in the transport / mixing step 210 is, for example, 8 to 2 to 2 to 8, preferably 8 to 2 to 3 to 7, and particularly preferably 7 to 3 to 5. As set to about 5, the dry coal is fed into the existing main coal feeding line 39 by an accurate amount (for example, 50 t / h) by the quantitative supply and metering system 36, the transfer conveyor 37 and the vertical conveyor 38. Rarely supplied.

In the coal drying processing facility 300, exhaust gas including exhaust heat discharged from a clinker cooler or the like in the cooling step 203 of the cement manufacturing facility 200 described above is supplied during the drying processing of the coal to be processed in the dryer 20. Used.
In addition, low-grade coal is highly pyrophoric, and there is a risk that low-grade coal may ignite in the dryer due to drying. For this reason, nitrogen gas, industrial water, and the like are used as fire extinguishing equipment for ignition in the dryer 20.
This exhaust gas is used for the drying treatment of coal to be treated even when the temperature is lowered to about 80 ° C. to about 200 ° C. when introduced into the dryer 20 as described above. And by the drying process by this dryer 20, the to-be-processed coal is dried so that it may become predetermined | prescribed moisture.

(Example of the second embodiment)
Hereinafter, the present invention will be described specifically by way of examples and comparative examples of the second embodiment.
The dryer used for the Example and the comparative example used the paddle stirring type dryer which has the structure equivalent to the said dryer 20, and implemented on the conditions similar to 1st Embodiment.
The properties of the treated coal (subbituminous coal) used in Examples and Comparative Examples are shown in Table 1 above. Moreover, the equilibrium water | moisture content of the to-be-processed coal (subbituminous coal) used for the Example and the comparative example is shown in the said Table 2, and was computed by the said Formula (1).

The drying heat source of the dryer, its flow rate, and the coal residence time were set to the same conditions as in the first embodiment. The drying air of the dryer (that is, the exhaust gas introduced into the dryer 20) was set so that the temperature was about 80 ° C. to about 180 ° C. and the air flow rate was 150 Nm ³ / h. The results of Examples and Comparative Examples performed under the above conditions are shown in Table 3 above. Since the description of the example and the comparative example of the second embodiment is the same as that described in the example of the first embodiment, the description is omitted here.

  As in Examples 1 to 3, also in the second embodiment, by appropriately controlling the supply amount of the coal to be treated and the drying gas temperature, the coal to be treated is reduced from the total moisture (about 32.8% by mass) to a predetermined moisture. In other words, it has been found that it is possible to dry to the lowest possible moisture without falling below the equilibrium moisture (about 17.6% by mass) of the coal to be treated. Moreover, in the existing coal-fired power plant, in order to prevent the ignition of coal in the pulverized coal mill, the temperature in the mill is controlled to 70 ° C. or less. The coal temperature observed in Examples 1 to 3 was lower than the control temperature, and it was confirmed that there was no safety problem.

  On the other hand, in the comparative example, the moisture of the dry coal is much lower than the equilibrium moisture as in the case of the first embodiment. Since moisture absorption after drying leads to loss of drying energy, it is not preferable as an operating condition. Moreover, since the temperature of dry coal exceeds the pulverized coal mill management temperature (70 degreeC) of a coal-fired power plant, it cannot be said that it is a preferable method as an operating condition also in terms of safety.

  As a result of the above, the total moisture of the coal is obtained by dry air at a temperature lower than the estimated temperature of about 200 ° C. to about 300 ° C. of the clinker cooler exhaust gas discharged from the cooling step 203 described above at a temperature of about 80 ° C. to about 180 ° C. Has been found to be possible to reduce to a predetermined moisture content.

  As described above, reducing the total moisture of the coal to be treated to a predetermined moisture (moisture exceeding the equilibrium moisture) using low level heat (for example, about 80 ° C. to about 180 ° C.) as a heat source has no safety problem. According to the processing system 1A according to the second embodiment, the heat energy discarded in the cement manufacturing facility 200 is used in the coal drying processing facility 300, and high-moisture coal (low-grade coal) is used as a high-quality coal such as bituminous coal. It can be dried to a quality equivalent to that of high-grade coal and effectively used as fuel.

  Thus, since this processing system 1A can aim at the fall of the total water | moisture content of the coal used with the coal thermal power generation equipment 100, it can aim at the improvement of the thermal efficiency at the time of combusting with the coal thermal power generation equipment 100. it can. At the same time, before being used in the coal-fired power generation facility 100, the coal drying treatment facility 300 is dried in advance with low-grade coal, and then mixed with high-grade coal is supplied to the coal-fired power generation facility 100. Therefore, it is possible to minimize the influence on the environment of dust and the like generated from low-grade coal during transportation and to improve the utilization rate of low-grade coal.

  And in this processing system 1A, the to-be-processed coal (dry coal) dried in the optimal state in Examples 1-3 is mounted on the main coal feeding line 39 of the existing non-process coal, and is supplied to the coal thermal power generation facility 100. 30% by mass was supplied to 70% by mass of high-grade coal such as bituminous coal to be sent. As a result, it was visually confirmed that blending can be performed in the transportation / mixing process 210 by repeatedly moving, dropping, and rolling on the transported belt conveyor. It was also confirmed that dust generation can be prevented as compared with the case where only low-grade coal is supplied to the coal-fired power generation facility 100. Furthermore, when the coal blended was burned with a small-scale combustion test device, the combustion performance was also good. Therefore, compared with the case where only dry low-grade coal is supplied to the coal-fired power generation facility 100, it is possible to reduce the total water content of the coal blended while preventing dust generation. Achieving a reduction in the total water content of coal combusted in the power generation facility 100, effectively improving thermal efficiency, and dramatically improving the utilization rate of low-grade coal such as subbituminous coal and lignite It became clear that it would be possible.

  As described above, according to the method and system for treating coal according to the second embodiment, the coal to be treated of low-grade coal is reformed to a quality equivalent to that of high-grade coal using existing equipment. Therefore, it is possible to expand the use of low-grade coal and to make effective use of resources.

  In addition, the treated coal (dry coal) after drying treatment has low possibility of ignition, is easy to handle and can be handled in the same way as high-grade coal, and exhaust heat of exhaust gas emitted from cement production Can be used as the energy for the drying treatment, so that it is possible to save energy through effective use of thermal energy in an environmentally favorable state, and to promote cost reduction of coal use.

(Third embodiment)
FIG. 6 is a block diagram showing an example of the overall flow of the coal processing system for realizing the coal processing method according to the third embodiment of the present invention, and FIG. 7 shows an example of the overall outline of the coal processing system. FIG. As shown in FIGS. 6 and 7, the coal processing system 1B includes a coal-fired power generation facility 100, a cement manufacturing facility 200 that is a hot gas supply facility, a coal drying processing facility 300, the coal-fired power generation facility 100, A coal accumulation relay facility (call center) 400 that accumulates and relays coal used as fuel in the cement manufacturing facility 200 is provided.

  In the present processing system 1B, as shown in FIG. 6, for example, high-grade coal such as bituminous coal 401 collected in the coal accumulation relay facility 400 passes through the transport process 208 and the transport / mixing process 210, and the coal thermal power generation facility 100 is transported. On the other hand, the coal to be treated 402, which is a low-grade coal such as subbituminous coal, is transported to the coal drying treatment facility 300 by another belt conveyor or the like.

  In the drying process 209 of the coal drying processing equipment 300, the hot gas from the cooling process 203 of the cement manufacturing equipment 200 is introduced, the drying treatment of the coal to be treated 402 is performed, and the pulverized coal discharged from the drying process 209 is removed. The contained exhaust gas is cooled by another gas. The dried coal dried in the drying step 209 is blended with the bituminous coal 401 in the belt on the transportation line following the transportation step 208, that is, the transportation / blending step 210, and then coal for fuel. As the fuel in the boiler process 110 of the coal-fired power generation facility 100.

  Examples of the coal combustion facility include the coal-fired power generation facility 100, a cement factory, an iron mill, and various factories. The coal to be treated that has been dried by the drying treatment facility is used as a fuel for boilers or a fuel for heating. Is done.

  The processing system 1B configured in this manner will be described in further detail. As shown in FIG. 7, the coal-fired power generation facility 100 has a plurality of different properties as described in the first and second embodiments. A facility that generates power by burning coal and is configured to include a power generation process similar to that of a known coal-fired power generation facility, and the coal-fired power generation facility 100 of the processing system 1, 1A in the above embodiment. It has the same configuration and process. Therefore, in the coal-fired power generation facility 100, first, coal obtained by blending (mixed coal) dry coal and bituminous coal 401 of the coal to be treated 402 supplied from the coal drying treatment facility 300 is pulverized using a vertical crusher or the like. In step 102, it is pulverized to a predetermined size. The subsequent boiler process (equivalent to the boiler process 110) 103, the power generation process 104, the feed water heating process 105, the denitration process 106, the heat recovery process 107, the dust collection process 108, and the desulfurization process 109 are as described above. The coal-fired power generation facility 100 in the coal processing system 1B according to the third embodiment generates electric power through these steps.

  In the present processing system 1B, the coal to be processed 402 is dried by the coal drying processing facility 300 before being supplied to the pulverization step 102, similarly to the processing system 1A. Examples of the coal to be treated 402 dried here include low-grade coal such as subbituminous coal. Of these, low-grade coal containing a large amount of moisture is preferably used. The coal 402 to be treated is dried so as to have the above-described predetermined moisture content.

  Here, the predetermined moisture is preferably as low as possible and does not fall below the equilibrium moisture in the atmosphere of the coal to be treated. Equilibrium moisture is moisture that is in an equilibrium state in an atmosphere of coal, and the equilibrium moisture depends on the temperature and humidity in the atmosphere. The treated coal 402 subjected to the drying process is discharged from the dryer outlet in the drying step 209, stored in a product silo, blended with the bituminous coal 401 by a belt conveyor, and transported to the coal-fired power generation facility 100. . Since the atmospheres of these processes, that is, the temperature and the humidity are different from each other, the dried coal to be treated absorbs and desorbs moisture (moisture varies) depending on the atmosphere of each process.

  And as above-mentioned, if it remove | excludes the water | moisture content of coal, it can aim at high calorific value, Therefore It is desirable that the water | moisture content of dry coal is as low as possible. However, in order to avoid waste of drying energy, it is necessary not to absorb moisture once treated coal. Therefore, it is preferable that the moisture after drying of the coal to be treated does not fall below the equilibrium moisture on the belt conveyor, that is, in the atmosphere, which is the final stage of each process described above.

  In addition, since the meaning of the water | moisture content which is not less than equilibrium water | moisture content and the drying conditions of drying equipment are as having described in 2nd Embodiment, description is abbreviate | omitted here. Here, the total moisture is moisture contained before or after the coal to be treated is dried. A coal sample for measuring total moisture is taken before being transported to the drying step 209. The total moisture is based on JIS M8820, and the equilibrium moisture is measured according to JIS A1475 using the treated coal as a sample. The equilibrium moisture content of the dry coal is obtained from the equilibrium moisture content curve obtained here and the temperature and relative humidity data in the atmosphere exposed to the dry coal. Since the obtained equilibrium moisture content is a percentage by mass of water based on the total mass after drying, the equilibrium moisture in the atmosphere of the dry coal can be obtained by the above formula (1).

  In the coal-fired power generation facility 100 according to the third embodiment, unlike the bituminous coal called a so-called high-grade coal among the coals having different properties depending on the coal drying treatment facility 300, the coal-fired power generation facility 100 has a low water content and is inexpensive. Coal to be treated such as sub-bituminous coal, which is a high-grade coal, is dried in advance so as to be as low as possible without lowering the equilibrium state, that is, the equilibrium moisture. In the coal processing system 1 </ b> B according to the third embodiment, thermal energy discharged from the cement manufacturing facility 200 is used in the coal drying processing facility 300.

  The configuration, operation, manufacturing process, and the like of the cement manufacturing facility 200 are as described above. In such a manufacturing process, particularly in the cooling process 203, a hot gas having a heat of about 300 ° C. is discharged from a clinker cooler or the like, but the heat of this hot gas is discharged almost without being used as it is. is the current situation. Therefore, the present processing system 1B can utilize the heat of this hot gas for the coal drying process 209 in the drying process 209 of the coal 402 to be processed in the coal drying processing facility 300 without almost modifying the existing facilities. It is configured.

  Further, the bituminous coal 401 is transported from the coal accumulation relay facility 400 to the coal drying treatment facility 300 through the transportation step 208 as it is, and the treated coal 402 is cooled in the drying step 209 in the cooling step of the cement manufacturing facility 200. The coal drying process using the thermal energy of the hot gas discharged from 203 is performed. Moreover, the exhaust gas containing the pulverized coal discharged from the drying step 209 is cooled by another gas. Then, the dried dry coal is blended (blended coal) with bituminous coal 401 transported in the transport and blending step 210 and then sent to the coal-fired power generation facility 100.

  As a result, as in the first and second embodiments, energy saving in coal utilization can be promoted to improve the fuel consumption rate, and a low-grade coal that has a high recoverable reserve and is inexpensive. Since the treated coal can be used in the same manner as high-grade coal, it is possible to extend the life of coal resources.

  Here, the coal drying processing facility 300 that realizes the transport / mixing process 210 including the drying process of the coal to be processed 402 in the drying process 209 described above will be described. FIG. 8 is an explanatory diagram for explaining an example of the coal drying processing facility 300 of the coal processing system 1B according to the third embodiment of the present invention. As shown in FIG. 8, first, low-grade coal is supplied to the bifurcated damper 3 from the existing coal delivery line 2 that continues from the coal accumulation relay facility 400, and low-grade coal that is not subjected to drying processing is installed in the bifurcated damper 3, for example. While being distributed to the coal transmission line 4 side, the coal to be treated, which is a low-grade coal to be dried, is distributed to the existing coal transmission line 5 side.

  The treated coal distributed to the existing coal transmission line 5 side is input to the receiving silo 9. The to-be-processed coal thrown into the receiving silo 9 is extracted from the receiving silo 9 by the extraction conveyor 12 and conveyed to the screw feeder 14 via the vertical conveyor 13. The treated coal transported to the screw feeder 14 is fed into the dryer 20 through the rotary valve 15.

  The dryer 20 is composed of, for example, the above-described known paddle agitation dryer, has the configuration and operation described in the first and second embodiments, and operates similarly. Here, it is preferable to dry the coal so that the temperature of the dried coal is 75 ° C. or less. The exhaust gas from the dryer 20 is cooled to 75 ° C. or lower by air having an atmospheric temperature as another gas introduced into the exhaust gas line, and is sent to the bag filter 19 by the exhaust fan 18. After the pulverized coal is removed by the bag filter 19, it is discharged into the atmosphere from the exhaust duct 31 by the bag filter fan 30.

  The exhaust gas line of the dryer 20 has a structure capable of introducing air at atmospheric temperature (atmosphere) as another gas different from the exhaust gas as illustrated, for example. For this reason, the exhaust gas is mixed with the atmosphere introduced in the exhaust gas line of the dryer 20 and cooled to a temperature of about 75 ° C. or less. Therefore, since the exhaust gas discharged into the atmosphere from the exhaust duct 31 has already been cooled, it is environmentally friendly, and even if there is some pulverized coal accompanied, there is little risk of ignition etc. can do.

  Moreover, it is preferable to further include a step of removing pulverized coal from a mixed gas of exhaust gas containing pulverized coal and another gas.

  Furthermore, since the exhaust gas is cooled in the exhaust gas line of the dryer 20 to a temperature of 75 ° C. or lower, the removal (separation) efficiency of pulverized coal accompanying the exhaust gas is improved, and the inside of the bag filter 19 is improved. Therefore, the coal drying treatment facility 300 can be stably operated.

  Although not shown in the figure, a pulverized coal removing device such as an electrostatic precipitator or a cyclone is further installed on the front side of the exhaust port of the bag filter 19 so that the pulverized coal still remains in the exhaust gas exhausted from the bag filter 19. You may make it have a double pulverized coal removal structure in preparation for the case where it was accompanied.

  The configuration and operation of the dryer 20 are as described above, and the coal to be treated is dried while being moved in the direction of the paddle shaft by the operation of the paddle 21 attached to the paddle shaft as described above. The

  And the dry coal carried out from the dryer 20 is thrown into the product silo 34 through the vertical conveyor 33 from the discharge conveyor 17. Note that the pulverized coal collected by the bag filter 19 is also fed into the product silo 34 by the pulverized coal transport system 35.

  As described above, since the pulverized coal is removed by the bag filter 19, the removed pulverized coal is in a dry state. Compared to performing pulverized coal removal by wet processing such as a scrubber, the pulverized coal transport system 35 Even if it is directly put into the product silo 34, the total moisture of the mixed dry coal is not increased. For this reason, according to this processing system 1B, the process of drying again the pulverized coal removed with the bag filter 19 becomes unnecessary, and the whole energy saving can be promoted.

  Then, the dry coal is supplied from the product silo 34 to the vertical conveyor 38 by a conveying conveyor 37 having a quantitative supply and weighing system 36, and is transported by being placed on the existing main coal feeding line 39 by the transporting process 208. It is blended by being dropped onto high-grade coal (bituminous coal). This part corresponds to the transportation / mixing process 210 described above. Thus, the blended (blended coal) coal is sent to the pulverization process 102 of the coal-fired power generation facility 100 and used as fuel for the fuel combustion boiler in the boiler process 103.

  The ratio of the blend of dry coal and bituminous coal (mixed coal) in this transport / mixing step 210 is, for example, 8 to 2 to 2 to 8, preferably 8 to 2 to 3 to 7, particularly preferably 7 The dry coal is supplied in an accurate amount (for example, 50 t / h) to the existing main coal supply line 39 by the fixed amount supply and metering system 36, the transfer conveyor 37 and the vertical conveyor 38 so that the ratio is set to about 3 to 5 to 5. Supplied on top. The coal blending method is not limited to the above, and examples include a method of supplying dry coal to a joint portion of a belt conveyor that transports bituminous coal, such as a chute portion. Bituminous coal and dry coal are blended by repeatedly moving, dropping and rolling on the transported belt conveyor.

In the coal drying treatment facility 300, when the coal to be treated in the dryer 20 is dried, the hot gas discharged from the clinker cooler or the like in the cooling step 203 of the cement manufacturing facility 200 described above is supplied and used.
In addition, low-grade coal is highly pyrophoric, and low-grade coal may ignite in the dryer due to drying. For this reason, it is preferable to install a device for supplying nitrogen gas and / or industrial water as a fire extinguishing facility for the ignition in the dryer 20.

  This hot gas is used for the drying treatment of the coal to be treated even when the temperature is lowered to about 80 ° C. to about 180 ° C. when introduced into the dryer 20 as described above. And by the drying process by this dryer 20, the to-be-processed coal is dried so that it may become predetermined | prescribed moisture.

(Example of the third embodiment)
Hereinafter, the present invention will be described specifically by way of examples and comparative examples of the third embodiment.
The dryer used for the Example and the comparative example used the paddle stirring type dryer which has the structure equivalent to the said dryer 20, and it implemented on the conditions similar to 1st and 2nd embodiment.

  The dryer used in this example has a cylindrical drying chamber with an inner dimension of φ268 mm × 740 mm, and is directly above the position 50 mm away from the side wall on the treated coal supply port side in the drying chamber in the paddle axis direction. Has a φ140 mm treated coal supply port, and is 140 mm × on the side wall (at a horizontal reference angle of 5 ° to 75 °) located 495 mm away from the side wall on the treated coal supply port side in the drying chamber in the paddle axis direction. It has a semicircular discharge port for discharging 140 mm of coal to be treated, and has a structure that can introduce air (atmosphere) of atmospheric temperature into the exhaust gas line above the discharge port. After cooling to a temperature, the exhaust gas removed by the cyclone is released to the atmosphere.

  The air dispersion plate between the drying chamber and the air chamber is provided with 3 mm × 140 mm slit openings at 45 mm intervals, and a 75 mm × 75 mm paddle is attached to the paddle shaft with an axis diameter of φ76.3 mm as viewed in the axial direction. The paddle shafts attached to the paddle shafts at intervals of 90 mm while being shifted from each other by 120 ° are horizontally mounted in the drying chamber, and a screw feeder for supplying the coal to be processed is provided above the coal supply port to be processed. In addition, in order to monitor the safety of the dryer, the temperature of the dry coal and the exhaust gas temperature above the discharge port were measured.

  The properties of the coal to be treated (subbituminous coal) used in Examples and Comparative Examples are shown in Table 1 above. Moreover, 17.6 mass% as shown in the said Table 2 used the equilibrium water | moisture content of the to-be-processed coal (subbituminous coal) used for the Example and the comparative example. Equilibrium moisture is obtained from temperature and relative humidity based on the equilibrium moisture content data of the coal to be treated obtained in accordance with the desiccator method (measurement temperature: 20 ° C. to 50 ° C., relative humidity: 10% to 98%). Create a correlation equation to find the equilibrium moisture, use the temperature and relative humidity in the conditions (atmosphere) under which the examples and comparative examples were implemented in the same equation to determine the equilibrium moisture content of the dry coal. It was calculated by equation (1).

  The drying capacity of the dryer was set so that the coal supply amount was about 20 kg / h to about 40 kg / h by adjusting the rotation speed of a screw feeder as a coal feeder. The drying heat source of the dryer, the flow rate thereof, and the coal residence time were set to satisfy the same conditions as those in the first and second embodiments.

  The results of Examples and Comparative Examples performed under the above conditions are shown in Table 3 above. Note that the effective volume used for calculating the heat capacity coefficient is the portion corresponding to the distance from the first slit of the gas dispersion plate to the discharge port in the volume of the drying chamber in which the coal stays. It was determined using a distance from 45 mm to 495 mm in the paddle axis direction from the side wall on the treated coal supply port side.

Hereinafter, examples and comparative examples will be described.
Example 1
As a result of carrying out the test with a coal supply rate of 20.4 kg / h and a drying heat source temperature of 82 ° C., the total moisture of the coal was 32.5% by mass at the time of supply, whereas after drying, it was 20.3% by mass Thus, the heat capacity coefficient was 5612 kcal / m ³ hr ° C. Moreover, the coal temperature at this time was 19.9 degreeC. The exhaust gas temperature at the top of the outlet was 55.4 ° C.
(Example 2)
As a result of conducting the test with a coal supply rate of 20.0 kg / h and a drying heat source temperature of 121 ° C., the total moisture of the coal was 33.1% by mass at the time of supply, whereas 19.0% by mass after drying. Thus, the heat capacity coefficient was 5236 kcal / m ³ hr ° C. Moreover, the coal temperature at this time was 25.3 degreeC. The exhaust gas temperature at the top of the outlet was 75.1 ° C. Therefore, the exhaust gas was cooled to 75 ° C. or less by supplying air to the exhaust gas.
(Example 3)
As a result of conducting the test with a coal supply amount of 40.1 kg / h and a drying heat source temperature of 180 ° C., the total moisture of the coal was 32.4% by mass at the time of supply, whereas 18.4% by mass after drying. Thus, the heat capacity coefficient was 5020 kcal / m ³ hr ° C. Moreover, the coal temperature at this time was 40.1 degreeC. The exhaust gas temperature at the top of the outlet was 82.0 ° C. Therefore, the exhaust gas was cooled to 75 ° C. or less by supplying air to the exhaust gas.
(Comparative example)
As a result of carrying out the test with a coal supply rate of 20.3 kg / h and a drying heat source temperature of 180 ° C., the total moisture of the coal was 32.9% by mass at the time of supply, but 12.1% by mass after drying. Thus, the heat capacity coefficient was 2747 kcal / m ³ hr ° C. Moreover, the coal temperature at this time was 79.0 degreeC. The exhaust gas temperature at the top of the outlet was 109.0 ° C. As a result, both dried coal and exhaust gas exceeded 75 ° C.

  As in Examples 1 to 3, also in the third embodiment, by appropriately controlling the supply amount of the coal to be treated and the drying heat source temperature, the coal to be treated is reduced from the total moisture (about 32.8% by mass) to a predetermined moisture. In other words, it has been found that it is possible to dry to the lowest possible moisture without falling below the equilibrium moisture (about 17.6% by mass) of the coal to be treated. Moreover, in the existing coal-fired power plant, in order to prevent the ignition of coal in the pulverized coal mill, considering the characteristics of the coal used, the temperature in the mill is 75 ° C. or lower, preferably 70 ° C. or lower, The temperature is preferably controlled to 50 ° C. or lower. The coal temperature observed in Examples 1 to 3 was lower than the control temperature, and it was confirmed that there was no safety problem.

  On the other hand, in the comparative example, the moisture of the dry coal was much lower than the equilibrium moisture as in the first and second embodiments, so that the moisture was absorbed again after drying. Since moisture absorption after drying leads to loss of drying energy, it is not preferable as an operating condition. Moreover, since the temperature of dry coal exceeds the maximum value (75 ° C.) of the pulverized coal mill management temperature of the coal-fired power plant, it cannot be said that it is a preferable method as operating conditions in terms of safety.

  As a result of the above, all of the coal is produced by the hot gas having a temperature of about 80 ° C. to about 180 ° C. lower than the assumed temperature of about 200 ° C. to about 300 ° C. of the clinker cooler hot gas discharged from the cooling step 203 described above. It has been found that it is possible to dry the moisture until it reaches a predetermined moisture content.

  As described above, reducing the total coal moisture of the coal to be treated to a predetermined moisture (moisture exceeding the equilibrium moisture) using low level heat (for example, about 80 ° C. to about 180 ° C.) as a heat source has no safety problem. According to the coal processing system 1B according to the third embodiment, the heat energy discarded in the cement manufacturing facility 200 is used in the coal drying processing facility 300, and high-moisture coal (low-grade coal) is used as bituminous coal. It can be dried to the same quality as high-grade coal and can be used effectively as fuel.

  Since the exhaust gas from the dryer 20 is also cooled to a temperature of 75 ° C. or lower and then exhausted, the total moisture of the dry coal is dried to the lowest possible moisture without falling below the predetermined moisture, that is, the equilibrium moisture. However, the possibility of ignition of pulverized coal in the exhaust gas is reduced to enable safe exhaust. As a result, it is possible to dry the coal to be treated in an optimum state in terms of both improvement in drying energy efficiency and safety.

  That is, the exhaust gas generated during drying in the drying process in the dryer 20 is mixed with the air to cool the exhaust gas to a temperature of 75 ° C. or lower, so that warming due to the exhaust gas discharged during drying The coal-fired power generation facility 100 can be stably operated and the coal drying treatment facility 300 can be stably operated by preventing the influence on the environment and the ignition of pulverized coal accompanying the high-temperature exhaust gas. Therefore, low-grade coal can be used safely and reliably.

  As described above, according to the coal treatment system 1B according to the third embodiment, the coal to be treated, particularly low-grade coal, is dried in the coal drying treatment facility 300 in a low-cost and efficient manner in an environmentally good state. In addition to being able to be used effectively in the coal-fired power generation facility 100, the exhaust gas discharged during drying prevents environmental influences and ignition, and the coal-fired power generation facility 100 can be operated stably. can do.

  In addition, since the coal to be treated (dry coal) after the drying treatment has a very low possibility of being ignited, it is easy to handle and can be handled in the same manner as high-grade coal, and is discharged at the cement manufacturing facility 200. Since the heat of the hot gas can be used as the energy for the drying process, it is possible to save energy by effectively using the thermal energy in an environmentally favorable state, and to promote the cost reduction of the use of coal.

  Furthermore, since the present processing system 1B can reduce the total moisture of the coal used in the coal-fired power generation facility, it is possible to improve the thermal efficiency when the coal-fired power generation facility 100 burns. At the same time, before being used in the coal-fired power generation facility 100, the coal drying treatment facility 300 is previously dried with low-grade coal and then blended with high-grade coal (mixed coal) is supplied to the coal-fired power generation facility 100. Therefore, it is possible to minimize the influence on the environment of dust and the like generated from low-grade coal during transportation and to improve the utilization rate of low-grade coal.

  As described above, according to the above-described method and system for treating coal according to the third embodiment, low-grade coal is efficiently dried by being dried at low cost and in an environmentally good state. In addition, it is possible to prevent the environmental impact and ignition caused by the exhaust gas discharged during drying, and to operate the coal utilization facility stably. In addition, according to the method and system for treating coal according to the third embodiment, the coal to be treated of low-grade coal is used after being reformed to a quality equivalent to that of high-grade coal using existing equipment. Therefore, it is possible to expand the use of low-grade coal and enable effective use of resources.

(Fourth embodiment)
FIG. 9 is a block diagram showing an example of the overall flow of a coal processing system for realizing the coal processing method according to the fourth embodiment of the present invention, and FIG. 10 shows an example of the overall outline of the coal processing system. FIG. As shown in FIGS. 9 and 10, the coal processing system 1 </ b> C basically has the same configuration as the processing system 1 </ b> B in the third embodiment, and includes a coal-fired power generation facility 100, a cement manufacturing facility 200, and the like. The coal drying processing facility 300 and the coal accumulation relay facility (call center) 400 are provided.

  In the present processing system 1C, as shown in FIG. 9, for example, high-grade coal such as bituminous coal 401 collected in the coal accumulation relay facility 400 passes through the transport process 208 and the transport / mixing process 210, and the coal-fired power generation facility 100 is transported. On the other hand, the coal to be treated 402, which is a low-grade coal such as subbituminous coal, is transported to the coal drying treatment facility 300 by another belt conveyor or the like.

  In the coal drying processing facility 300, whether or not the drying process of the coal to be processed 402, which will be described later, is determined in the determination step 209P is determined. In step 209, the hot gas from the cooling step 203 of the cement manufacturing facility 200 is introduced to dry the coal to be treated 402, and the exhaust gas containing pulverized coal discharged from the drying step 209 is other Cooled by gas. The dried coal dried in the drying step 209 is blended with the bituminous coal 401 in the belt on the transportation line following the transportation step 208, that is, the transportation / blending step 210, and then coal for fuel. As the fuel in the boiler process 110 of the coal-fired power generation facility 100. Specific examples of the coal blending method include a method of supplying dry coal to bituminous coal transported by a belt conveyor, a method of supplying dry coal to a joint portion of a belt conveyor for transporting bituminous coal, such as a chute portion, and the like. Bituminous coal and dry coal are blended by repeatedly moving, dropping and rolling on the transported belt conveyor. Examples of coal combustion facilities include the coal-fired power generation facility 100, cement factories, steel mills, and various factories. The treated coal dried by the coal drying treatment facility 300 is used as boiler fuel or heating fuel. Is done.

  The processing system 1C configured as described above will be described in more detail. As shown in FIG. 10, the coal-fired power generation facility 100 has a plurality of different properties as described in the first to third embodiments. A facility that generates power by burning coal, and includes a power generation process similar to that of a known coal-fired power generation facility, and is equivalent to the coal-fired power generation facility 100 of the processing system 1B in the above embodiment. The structure and process are provided. Therefore, the pulverization process 102, the boiler process (equivalent to the boiler process 110) 103, the power generation process 104, the feed water heating process 105, the denitration process 106, the heat recovery process 107, the dust collection process 108, and the desulfurization of the coal-fired power generation facility 100 Step 109 is as described above, and power is generated in the coal-fired power generation facility 100 in the coal processing system 1C according to the fourth embodiment by these steps.

  In the present processing system 1C, similarly to the above processing system 1B, before being supplied to the pulverizing step 102, the coal to be processed out of various types of coal is dried by the coal drying processing facility 300. Examples of the coal to be dried here include low-grade coals such as subbituminous coal and lignite. Among these, low-grade coal that contains a lot of moisture and is inexpensive is preferably used. The coal to be treated is dried so as to have the predetermined moisture content described above.

  Here, the predetermined moisture, equilibrium moisture, moisture not lower than the equilibrium moisture, total moisture, etc. are as described in the third embodiment, so the explanation is omitted here, and the drying conditions of the drying equipment are the coal to be treated. It is set as appropriate according to the total water content and the equilibrium water content in the atmosphere. Moreover, the equilibrium water | moisture content in the atmosphere of dry coal can be calculated | required similarly by said Formula (1). The coal sample for measuring the total moisture is collected in the determination step 209P before being transported to the drying step 209.

  In the coal-fired power generation facility 100 according to the fourth embodiment, among the coals having different properties, the coal drying processing facility 300 determines whether or not the drying process is necessary in the determination step 209P, so-called high-grade coal. Unlike bituminous coal called, sub-bituminous coal such as sub-bituminous coal, which is a low-grade coal that contains a lot of water and is cheap, is not less than the above condition, that is, equilibrium water, when it is determined that drying treatment is required It is dried in advance so that the moisture content is as low as possible. In the coal processing system 1C according to the fourth embodiment, thermal energy discharged from the cement manufacturing facility 200 is used in the coal drying processing facility 300.

  The configuration, operation, manufacturing process, and the like of the cement manufacturing facility 200 are as described above. In such a manufacturing process, particularly in the cooling process 203, a hot gas having a heat of about 300 ° C. is discharged from a clinker cooler or the like, but the heat of this hot gas is discharged almost without being used as it is. is the current situation. Therefore, the present processing system 1C can utilize the heat of this hot gas for the coal drying process 209 in the drying process 209 of the coal 402 to be processed in the coal drying processing facility 300 without almost modifying existing facilities. It is configured.

  Further, the bituminous coal 401 is transported from the coal accumulation relay facility 400 to the coal drying processing facility 300 through the transporting process 208 as it is, and it is determined that a drying process is required in the determination process 209P of the coal 402 to be processed. The treated coal 402 is subjected to a coal drying process using the thermal energy of the hot gas discharged from the cooling process 203 of the cement manufacturing facility 200 in the drying process 209. Moreover, the exhaust gas containing the pulverized coal discharged from the drying step 209 is cooled by another gas. Then, the dried dry coal is blended (blended coal) with bituminous coal 401 transported in the transport and blending step 210 and then sent to the coal-fired power generation facility 100.

  As a result, as in the first to third embodiments, energy saving in coal utilization can be promoted to improve the fuel consumption rate, and a low-grade coal that has a high recoverable reserve and is inexpensive. Since the treated coal can be used in the same manner as high-grade coal, it is possible to extend the life of coal resources.

  Here, the coal drying processing facility 300 that realizes the transport / mixing process 210 including the drying process of the treated coal 402 in the determination process 209P and the drying process 209 described above will be described with reference to FIG. As shown in FIG. 8, first, coal is supplied to the bifurcated damper 3 from the existing coal delivery line 2 that continues from the coal accumulation relay facility 400, and untreated coal that is not worthy of drying processing is supplied to the existing bifurcated damper 3 While being distributed to the coal line 4 side, the coal to be treated to be dried is distributed to the existing coal transmission line 5 side.

  The treated coal distributed to the existing coal transmission line 5 side is input to the receiving silo 9. The to-be-processed coal thrown into the receiving silo 9 is extracted from the receiving silo 9 by the extraction conveyor 12 and conveyed to the screw feeder 14 via the vertical conveyor 13. The treated coal transported to the screw feeder 14 is fed into the dryer 20 through the rotary valve 15.

  The energy required to remove coal adhering moisture is about the latent heat of vaporization of water, whereas the removal of moisture in the particles (crystal water and pore water) other than adhering moisture is more than the removal of adhering moisture. Requires energy. Therefore, coal to be treated which is a drying target is preferably coal with a large amount of attached moisture. Since coal with a large amount of attached moisture can increase the amount of moisture reduction, the merit due to the drying operation, that is, the amount of increase in calorific value is increased. On the other hand, since coal with little moisture adheres has a small merit by the drying operation, it is determined that it is not worthy of drying treatment, and is blended (blended coal) with dry coal as untreated coal.

  In the fourth embodiment, the moisture adhering to the coal is defined as the value obtained by subtracting the equilibrium moisture from the total moisture in the determination step 209P described above, and the necessity of the drying process is determined using the value obtained by subtracting the equilibrium moisture from the total moisture of the coal. It is characterized by being decided. Since the total moisture varies depending on the weather and season, it is measured every time the coal is used (every time it is determined whether or not to dry). The equilibrium moisture is an eigenvalue for each coal type (coal brand). Therefore, it is not necessary to measure each time the coal is used. Equilibrium moisture in the external environment (due to temperature and humidity) at the time of use can be obtained from an estimation formula specific to the coal type obtained based on equilibrium moisture data measured for each coal type in advance. “Equilibrium moisture” is known information for each type of coal (measurement time may take several days or more in some cases), and “total moisture” is measured each time (influences on coal storage conditions and weather conditions such as rainfall) Therefore, the above numerical value is calculated and discriminated. In addition, if total moisture is measured in accordance with JIS, it takes several hours or more of measurement time. In some cases, a simple measurement method (such as omitting pretreatment such as grinding) is used. It is also possible to do.

  Equilibrium moisture is a specific value determined by the type of coal. Varies with ambient temperature and humidity. Experimentally, it can be calculated as a function of temperature and humidity for each coal type. Therefore, if the type of coal to be used is determined, it can be calculated based on the atmospheric conditions (temperature / humidity) at that time (or assuming the time when the coal is used). Whether or not the drying process is necessary is determined based on whether or not the value obtained by subtracting the “equilibrium water content” obtained above from the “total water content” measured each time is within a suitable range.

  In addition, determination of the necessity of the drying process in the determination process 209P is good based on the information of the total water | moisture content and equilibrium water | moisture content of coal. Table 4 below shows the total moisture, equilibrium moisture, and the value obtained by subtracting the equilibrium moisture content from the total moisture content for two types of coal of different grades. The total moisture was measured according to JIS M8820 (coal and coke-lot total moisture measurement method). Further, the equilibrium moisture is a numerical value calculated under the conditions (average atmospheric temperature and average relative humidity) of a temperature of 30 ° C. and a relative humidity of 75%, respectively, according to the above-described formula (1) created for each coal type. Total moisture varies with coal storage conditions, and equilibrium moisture varies with atmospheric temperature and relative humidity. Therefore, the numerical value obtained by subtracting the equilibrium moisture from the total moisture varies depending on the coal storage situation, the atmospheric temperature and the relative humidity.

  In the fourth embodiment, the difference between the equilibrium moisture and the total moisture is defined as adhering moisture, and coal with a large amount of adhering moisture (coal with a large amount of moisture reduction per drying energy) is determined as a coal that needs to be dried. Features. In the determination step 209P, whether or not the drying treatment is necessary is determined as a coal to be treated that requires drying treatment when the value obtained by subtracting the equilibrium moisture from the total moisture of the coal is 8 or more. In some cases, it is preferable that the determination is made as untreated coal that does not require a drying process.

In general, low-grade coal, which has a high total water content, has a numerical value exceeding 8 and is often determined to be treated coal that needs to be dried. However, the value obtained by subtracting the equilibrium moisture from the total moisture may decrease due to coal storage conditions and atmospheric temperature and relative humidity fluctuations, and this value may be less than 8. In this case, Determined.
Conversely, even for high-grade coal, which is generally considered to have a low total moisture, the value obtained by subtracting the equilibrium moisture from the total moisture increases due to the coal storage situation and fluctuations in atmospheric temperature and relative humidity. If it exceeds, it is determined to be treated coal.

Here, the total water content of the coal required for the determination of sorting is measured in advance by an analysis method such as JIS M8820 (Coal and coke-lot total water content measurement method) or other water content measurement. Perform by device. Other moisture measuring devices include a halogen moisture meter and an infrared moisture meter. However, the drying temperature at the time of moisture measurement is preferably 107 ° C. or lower in order to prevent coal alteration.
In addition, although illustration is omitted, a moisture measuring device is installed in the existing coal feeding line 2, and a control device for controlling the bifurcated damper 3 with information on the total moisture of coal from the moisture measuring device and equilibrium moisture is installed, It is also possible to determine whether or not the drying process is necessary by the control device, and to control the bifurcated damper 3 based on the determination result.

  For example, if it is determined that the value obtained by subtracting the equilibrium moisture from the total moisture of the coal is 8 or more, it is distributed to the existing coal transmission line 5 side as being necessary for the drying process, and this value is less than 8 When it is determined, it is distributed to the existing coal transmission line 4 side because the drying process is unnecessary. Note that the coal distributed to the existing coal transmission line 4 side is, for example, sent back to the coal accumulation relay facility and stored again, or used for other purposes.

The drying process is preferably performed so that the total moisture of the coal after the drying process exceeds the equilibrium moisture.
As a result, once dried coal absorbs moisture before use, it is possible to prevent the total moisture of the coal from rising, and avoid waste of drying energy.

  The coal to be treated, which is distributed to the existing coal transmission line 5 and needs to be dried, is put into the receiving silo 9. The coal to be treated that has been input to the receiving silo 9 is extracted from the receiving silo 9 by the extraction conveyor 12 and conveyed to the screw feeder 14 via the vertical conveyor 13. The treated coal transported to the screw feeder 14 is fed into the dryer 20 through the rotary valve 15.

  The dryer 20 is composed of, for example, the above-described known paddle agitation dryer, has the configuration and operation described in the first to third embodiments, and operates similarly. Then, the coal to be treated that has been agitated and dried is carried out of the dryer 20 by the discharge conveyor 17 through the rotary valve 16. The exhaust gas from the dryer 20 is sent to the bag filter 19 by the exhaust fan 18, and after dust (fine powder etc.) is removed by the bag filter 19, the bag filter fan 30 passes the exhaust gas from the exhaust duct 31 to the atmosphere. To be discharged.

  In this dryer 20, as demonstrated in 3rd Embodiment, it is preferable to dry coal so that the temperature of the coal after drying may be 75 degrees C or less. Thereby, the possibility that dry coal will ignite can be suppressed effectively. For this purpose, it is preferable to appropriately set drying conditions of the drying equipment such as the supply amount of coal, the temperature of the drying heat gas, the supply amount of the drying heat gas, and the rotational speed of the paddle, and monitor the temperature in the dryer.

  The exhaust gas of the dryer 20 is mixed with the atmosphere introduced through the exhaust gas line of the dryer 20 and cooled to a temperature of about 75 ° C. or lower. Therefore, since the exhaust gas discharged into the atmosphere from the exhaust duct 31 has already been cooled, it is environmentally friendly, and even if there is some pulverized coal accompanied, there is little risk of ignition etc. can do.

  Moreover, it is preferable to further include a step of removing pulverized coal from a mixed gas of exhaust gas containing pulverized coal and another gas.

  Furthermore, since the exhaust gas is cooled in the exhaust gas line of the dryer 20 to a temperature of 75 ° C. or lower, the removal (separation) efficiency of pulverized coal accompanying the exhaust gas is improved, and the inside of the bag filter 19 is improved. Therefore, the coal drying treatment facility 300 can be stably operated.

  Although not shown in the figure, a pulverized coal removing device such as an electrostatic precipitator or a cyclone is further installed on the front side of the exhaust port of the bag filter 19 so that the pulverized coal still remains in the exhaust gas exhausted from the bag filter 19. You may make it have a double pulverized coal removal structure in preparation for the case where it was accompanied.

  The configuration and operation of the dryer 20 are as described above, and the coal to be treated is dried while being moved in the paddle shaft direction as described above. And the dry coal carried out from the dryer 20 is thrown into the product silo 34 through the vertical conveyor 33 from the discharge conveyor 17. Note that the pulverized coal collected by the bag filter 19 is also fed into the product silo 34 by the pulverized coal transport system 35.

  As described above, since the pulverized coal is removed by the bag filter 19, the removed pulverized coal is in a dry state. Compared with the case where the pulverized coal is removed by a wet process such as a scrubber, the pulverized coal transport system 35 If directly put into the product silo 34, the total moisture of the mixed dry coal will not be increased. For this reason, according to this processing system 1C, the process of drying the pulverized coal removed with the bag filter 19 again becomes unnecessary, and the whole energy saving can be promoted.

  Then, the dry coal is supplied from the product silo 34 to the vertical conveyor 38 by a conveying conveyor 37 having a quantitative supply and weighing system 36, and is transported by being placed on the existing main coal feeding line 39 by the transporting process 208. It is blended by being dropped onto high-grade coal (bituminous coal). This part corresponds to the transportation / mixing process 210 described above. Thus, the blended (blended coal) coal is sent to the pulverization process 102 of the coal-fired power generation facility 100 and used as fuel for the fuel combustion boiler in the boiler process 103.

  The ratio of the blend of dry coal and bituminous coal (mixed coal) in this transportation / mixing step 210 is, for example, 8 to 2 to 2 to 8, preferably 8 to 2 to 3 to 7, particularly preferably 7 to 3 to 5. As set to about 5, the dry coal is fed into the existing main coal feeding line 39 by an accurate amount (for example, 50 t / h) by the quantitative supply and metering system 36, the transfer conveyor 37 and the vertical conveyor 38. Rarely supplied.

In the coal drying treatment facility 300, when the coal to be treated in the dryer 20 is dried, the hot gas discharged from the clinker cooler or the like in the cooling step 203 of the cement manufacturing facility 200 described above is supplied and used.
In addition, low-grade coal is highly pyrophoric, and low-grade coal may ignite in the dryer due to drying. For this reason, it is preferable to install an apparatus for supplying nitrogen gas and / or industrial water as fire extinguishing equipment for the ignition in the dryer 20.

  This hot gas is used for the drying treatment of the coal to be treated even when the temperature is lowered to about 80 ° C. to about 180 ° C. when introduced into the dryer 20 as described above. And by the drying process by this dryer 20, the to-be-processed coal is dried so that it may become predetermined | prescribed moisture.

(Example of the fourth embodiment)
Hereinafter, the present invention will be described specifically by way of examples and comparative examples of the fourth embodiment.
The dryer used for the Example and the comparative example used the paddle stirring type dryer which has the structure equivalent to the said dryer 20, and implemented on the conditions similar to 3rd Embodiment.

  The dryer used in this example is the same as that used in the example of the third embodiment. The properties of the treated coal (subbituminous coal) used in Examples and Comparative Examples are shown in Table 1. The method for measuring the total moisture and the like is also as described above. Moreover, the equilibrium water | moisture content was computed by the said Formula (1).

  As mentioned above, the to-be-processed coal (subbituminous coal) used for the Example and the comparative example has a total moisture of 32.8% by mass and an equilibrium moisture of 17.6% by mass, and the numerical value obtained by subtracting the equilibrium moisture from the total moisture is Since it exceeds 8, it is coal worthy of drying (coal to be treated).

  The drying capacity of the dryer, the drying heat source of the dryer, the flow rate thereof, and the coal residence time were set to satisfy the same conditions as in the third embodiment. The results of Examples and Comparative Examples performed under the above conditions are shown in Table 3 above. Descriptions of the examples and the comparative examples are the same as those described in the examples of the third embodiment, and thus description thereof is omitted here.

  As in Examples 1 to 3, also in the fourth embodiment, by appropriately controlling the supply amount of the coal to be treated and the drying heat source temperature, the coal to be treated is reduced from the total moisture (about 32.8% by mass) to a predetermined moisture. In other words, it has been found that it is possible to dry to the lowest possible moisture without falling below the equilibrium moisture (about 17.6% by mass) of the coal to be treated. Moreover, in the existing coal-fired power plant, in order to prevent the ignition of coal in the pulverized coal mill, considering the characteristics of the coal used, the temperature in the mill is 75 ° C. or lower, preferably 70 ° C. or lower, The temperature is preferably controlled to 50 ° C. or lower. The coal temperature observed in Examples 1 to 3 was lower than the control temperature, and it was confirmed that there was no safety problem.

  On the other hand, in the comparative example, the moisture of the dry coal was much lower than the equilibrium moisture as in the first to third embodiments, so that moisture was absorbed again after drying. Since moisture absorption after drying leads to loss of drying energy, it is not preferable as an operating condition. Moreover, since the temperature of dry coal exceeds the maximum value (75 ° C.) of the pulverized coal mill management temperature of the coal-fired power plant, it cannot be said that it is a preferable method as operating conditions in terms of safety.

  As a result of the above, all of the coal is produced by the hot gas having a temperature of about 80 ° C. to about 180 ° C. lower than the assumed temperature of about 200 ° C. to about 300 ° C. of the clinker cooler hot gas discharged from the cooling step 203 described above. It has been found that it is possible to dry the moisture until it reaches a predetermined moisture content.

  As described above, reducing the total coal moisture of the coal to be treated to a predetermined moisture (moisture exceeding the equilibrium moisture) using low level heat (for example, about 80 ° C. to about 180 ° C.) as a heat source has no safety problem. According to the coal processing system 1C according to the fourth embodiment, the heat energy discarded in the cement manufacturing facility 200 is used in the coal drying processing facility 300 to convert high moisture coal (low-grade coal) to bituminous coal. It can be dried to the same quality as high-grade coal and can be used effectively as fuel. Other functions and effects are the same as those of the third embodiment. That is, according to the method and system for treating coal according to the fourth embodiment described above, low-grade coal can be effectively dried and dried at low cost and in good condition in terms of the environment. In addition, it is possible to prevent the environmental impact and ignition caused by the exhaust gas discharged during drying, and to operate the coal utilization facility stably. In addition, according to the method and system for treating coal according to the fourth embodiment, the treated coal of low-grade coal is used after being reformed to a quality equivalent to high-grade coal using existing equipment. Therefore, it is possible to expand the use of low-grade coal and enable effective use of resources.

  The treated coal to be dried is preferably low-grade coal such as subbituminous coal or lignite with a large amount of adhering moisture as described above, but is not limited thereto. For example, coal such as low-grade coal is reformed (reducing moisture) by appropriately combining various operations such as heating, pressurization, drying, and dehydration. What was formed into pellets and / or briquettes can be used. The reformed and pelletized or / and briquetted coal is stored outdoors before being used in a coal-fired power plant. Pellet-like and / or briquette-like coal whose water content has increased again due to rainwater or the like during storage can be dried as needed and used in a coal-fired power generation facility.

DESCRIPTION OF SYMBOLS 1 Coal processing system 2 Existing coal line 3 Bifurcated damper 4 Existing coal line 5 Existing coal line 6 Moisture meter 7 Controller 9 Receiving silo 12 Extraction conveyor 13 Vertical conveyor 14 Screw feeder 15 Rotary valve 16 Rotary valve 17 Discharge Conveyor 18 Ventilator 19 Bag filter 20 Dryer 21 Paddle 22 Gas (air) dispersion plate 30 Bag filter fan 31 Exhaust duct 33 Vertical conveyor 34 Product silo 35 Dust (pulverized coal) transport system 36 Fixed supply weighing system 37 Transport conveyor 38 Vertical Conveyor 39 Existing main coal line 100 Coal-fired power generation facility 102 Grinding process 103 Boiler process 104 Power generation process 105 Feed water heating process 106 Denitration process 107 Heat recovery process 108 Dust collection process 1 9 desulfurization step 200 cement production facility 201 pulverization step 202 baking step 203 the cooling step 204 finishing step 208 transportation step 209 drying step 210 transport and CCS, the imported coal is blended step 300 coal drying treatment facility 400 coal integrated relay equipment 401 bituminous coal (high-grade coal)
402 Coal to be treated (low grade coal)
500 Coal Accumulation Relay Facility 501 Bituminous Coal 502 Subbituminous Coal 503 Coal Mixing Process 504 Transport Process 600 Cement Manufacturing Facility 601 Transport Process 700 Coal Thermal Power Generation Facility 701 Boiler Process

Claims (11)

In a method of treating coal that is dried and burned in a coal-fired power plant,
A gas dispersion plate divides the interior into an upper drying chamber and a lower gas chamber, and a horizontal paddle shaft is rotatably provided in the drying chamber, and coal is spaced apart in the axial direction of the paddle shaft. Supplying coal into the drying chamber of a paddle stirring dryer equipped with a plurality of paddles for stirring;
A method for treating coal, in which hot gas is supplied into the gas chamber from a hot gas supply facility different from the coal-fired power generation facility to dry the coal. Blending the dried dry coal with untreated coal other than the dry coal;
The coal processing method according to claim 1, further comprising: feeding coal that has been mixed into the coal-fired power generation facility. The method for treating coal according to claim 1, further comprising a step of cooling the exhaust gas containing the pulverized coal by mixing another gas with the exhaust gas containing the pulverized coal discharged from the drying facility. A step of determining whether or not the coal needs to be dried before drying the coal, and whether or not the drying treatment is necessary is determined based on information on the total moisture and equilibrium moisture of the coal before drying. ,
The method for treating coal according to any one of claims 1 to 3, wherein the coal to be treated having a predetermined property that is determined to require drying treatment is dried so as to be in a predetermined state. The method for treating coal according to claim 1, wherein the hot gas supply facility is a cement manufacturing facility. The method for treating coal according to claim 2, wherein the blended coal is supplied by supplying the dry coal to a transportation means for transporting the untreated coal. The method for treating coal according to claim 3, wherein the exhaust gas is cooled to a temperature of 75 ° C. or less. Whether or not the drying process is necessary is determined when the numerical value obtained by subtracting the equilibrium moisture content from the total moisture content of the coal is 8 or more, the drying process is determined to be necessary, and when the numerical value is less than 8. The method for treating coal according to claim 4, wherein the method is performed by determining that the drying treatment is unnecessary. The coal treatment method according to claim 1, wherein the coal to be treated is obtained by reforming coal and molding and processing it into pellets and / or briquettes. The method for treating coal according to claim 1, wherein the drying treatment is performed so that the total moisture of the coal after the drying treatment exceeds the equilibrium moisture.   In a coal processing system that dries coal and burns it with a coal-fired power generation facility, the interior is partitioned into an upper drying chamber and a lower gas chamber by a gas dispersion plate, and a horizontal paddle shaft rotates in the drying chamber. A supply port for supplying coal is provided in the drying chamber of a paddle agitation dryer in which a plurality of paddles for agitating coal are attached at intervals in the axial direction of the paddle shaft. The gas chamber is provided with a hot gas supply port for supplying hot gas for drying coal, and the hot gas supply port is connected to an exhaust gas exhaust line of a clinker cooler of a cement manufacturing facility. Coal processing system characterized by.

Images