JP5323024B2 - Method for producing biomass mixed fuel - Google Patents

Description

  The present invention relates to a method for producing a biomass mixed fuel.

  2. Description of the Related Art Conventionally, it is known that a coal-fired power plant uses a biomass mixed fuel obtained by mixing biomass fuel with coal to burn and generate power. Biomass fuel is supplied from the outside of the coal-fired power plant to the fuel supply facility of the coal-fired power plant, and is accumulated and stored in a storage facility such as a silo before the biomass fuel is mixed with coal. And since biomass fuel is made to co-fire with coal, after performing a required process, it is co-fired with coal (refer patent document 1).

JP 2005-291539 A

  However, when stored in a storage facility such as a silo, the biomass fuel may be clogged at the silo outlet when the biomass fuel is transported from the silo. In addition, when the biomass fuel received from the outside has a plurality of different types and dimensions, a plurality of silos that accept the biomass fuel are required in accordance with this, and equipment costs for installing a plurality of silos were required. . In addition, it takes time and effort to maintain and manage the silo according to the amount and type of biomass fuel received.

  An object of the present invention is to produce a mixed fuel by mixing biomass fuel with coal by a simpler method.

  (1) The manufacturing method of the biomass mixed fuel of this invention is equipped with the temporary receiving area which receives the said biomass fuel temporarily in the fuel supply equipment of the coal thermal power plant which uses the biomass mixed fuel which mixed biomass fuel with coal. The temporary receiving area is a flat area where vehicles can directly enter, and the coal and the biomass fuel are mixed within 24 hours from the temporary receiving in the temporary receiving area.

  (2) The fuel supply facility includes a delivery mechanism that delivers the biomass fuel from the temporary receiving area by a certain amount, and a transportation unit that mixes and transports the biomass fuel and the coal that are delivered from the delivery mechanism, The biomass fuel and the coal are mixed by the transport means having a predetermined transport speed after the amount of the biomass fuel sent out by the feed mechanism is measured, and the biomass fuel feed amount and / or the transport speed is adjusted. Accordingly, it is preferable to adjust the mixing ratio of the biomass fuel and the coal.

  (3) It is preferable that the biomass fuel mixed with the coal is always 3% by mass or less with respect to the coal.

  (4) The fuel supply facility includes a coal storage area that stores coal and a bunker that temporarily stores mixed fuel, and is determined by a coal transfer time and a coal transfer amount. Based on the plan to send coal to the bunker, the biomass fuel mixing plan determined by the mixing time and amount of the biomass fuel is determined, and the mixing of the biomass fuel and coal is performed based on the mixing plan. Preferably it is done.

  (5) It is preferable to determine the maximum amount of the biomass fuel received per day by the coal feeding plan and the mixing plan.

  According to the present invention, it is possible to provide a method for producing a mixed fuel by mixing biomass fuel with coal by a simpler method.

It is the schematic which shows the fuel supply equipment of this invention.

  Hereinafter, a preferred embodiment of the fuel supply facility 100 in a coal-fired power plant according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a fuel supply facility 100 according to an embodiment of the present invention. The fuel supply facility 100 receives the supply of biomass fuel from the outside in a coal-fired power plant that uses a mixed fuel obtained by mixing biomass fuel with coal, and supplies the mixed fuel by mixing coal and biomass fuel. It is equipment to do. The biomass fuel in the present invention is a plant-based fuel obtained from waste wood, thinned wood, etc., and is so-called woody biomass fuel.

  As shown in FIG. 1, a fuel supply facility 100 includes a temporary receiving area 1 that temporarily receives biomass fuel, a coal storage area 2 that stores coal, and a mill-type pulverized coal machine that pulverizes a mixed fuel of coal and biomass fuel. 3 (hereinafter referred to as a pulverized coal machine), a bunker 4 for supplying mixed fuel to the pulverized coal machine 3, a belt conveyor 20 and a biomass supply conveyor 10 as conveying means for conveying coal and biomass fuel, and a temporary receiving area 1 and a delivery mechanism 7 for delivering biomass fuel to the biomass supply conveyor 10.

  The provisional receiving area 1 is a flat area into which the vehicle 11 can directly enter. A vehicle 11 loaded with biomass fuel enters the provisional receiving area 1 and carries the biomass fuel. In the provisional receiving area 1, the loaded biomass fuel is accommodated within 24 hours. The temporary receiving area 1 is a semi-indoor, and a roof is provided so that the humidity of the biomass fuel does not increase due to rain or the like. Biomass fuel is fermented at the stage of being supplied to a coal-fired power plant from the outside, and has a temperature of 30 ° C to 40 ° C.

  The coal storage area 2 is an area for temporarily storing massive coal carried into the fuel supply facility 100 from the outside. The coal storage area 2 is provided in the semi-indoor, and a conveyance port of the belt conveyor 20 extending from the coal storage area 2 toward the bunker 4 and the pulverized coal machine 3 is provided.

  The belt conveyor 20 extends from the coal storage area 2 to the bunker 4. The belt conveyor 20 includes a base end portion on the coal storage area 2 side and a terminal end portion on the bunker 4 side. The length from the base end part to the terminal end part of the belt conveyor 20 can be 50 m or more and 500 m or less. The belt conveyor 20 conveys coal from the coal storage area 2 to the bunker 4. Biomass fuel is supplied to the coal carried on the belt of the belt conveyor 20, and the belt conveyor 20 mixes the coal and the biomass fuel.

  The biomass supply conveyor 10 extends from the temporary receiving area 1 to the belt conveyor 20. The biomass supply conveyor 10 moves with the biomass fuel placed on the belt, and supplies the biomass fuel to the belt conveyor 20. The biomass conveyor side of the biomass supply conveyor is disposed above the belt conveyor 20 at a position overlapping the belt conveyor 20. The biomass fuel transported on the biomass supply conveyor 10 drops and is supplied onto the belt conveyor 20 that transports the coal, and is mixed with the coal on the belt conveyor 20.

  The delivery mechanism 7 is provided at the base end of the biomass supply conveyor 10 on the receiving area 1 side. The delivery mechanism 7 includes a screw 71 that sends biomass fuel from the temporary receiving area 1 to the biomass supply conveyor 10, a quantitative feeder 72 that is provided on the downstream side of the screw 71 and measures the amount of biomass fuel sent to the biomass supply conveyor 10, Have The delivery mechanism 7 delivers a certain amount of biomass fuel from the provisional receiving area 1.

  The screw 71 has a supply port for supplying biomass fuel at one end, and this supply port is disposed in the temporary receiving area 1. The other end of the screw 71 is provided with a quantitative feeder 72 that measures the amount of biomass fuel and supplies it to the biomass supply conveyor 10. The amount of biomass fuel delivered from the temporary receiving area 1 is adjusted by the rotational speed of the screw 71. The quantitative feeder 72 measures the amount of biomass fuel and supplies a predetermined amount of biomass fuel onto the biomass supply conveyor 10. The amount of biomass fuel to be sent out is adjusted to a constant amount by the delivery mechanism 7 and measured.

  The biomass supply conveyor 10 and the belt conveyor 20 as conveying means mix and convey the biomass fuel and coal fed from the feeding mechanism 7 after weighing by the feeding mechanism 7. The conveyance speeds of the biomass supply conveyor 10 and the belt conveyor 20 are appropriately adjusted according to the amount of coal fed and the amount of biomass fuel fed so that biomass fuel is mixed with coal at 3 mass% or less. The biomass fuel mixing rate is adjusted in accordance with the amount of biomass fuel delivered by the delivery mechanism 7 and / or the transport speed of the transport means. For example, when the belt conveyor 20 for transporting coal is transporting coal at a speed of 1000 t / hour, the biomass supply conveyor 10 is configured to supply biomass fuel at a speed of 7.5 to 20 t / h per hour. Adjustments can be made to transport the fuel. Only the speed of the belt conveyor 20 may be changed, only the biomass supply conveyor 10 may be changed, and both may be adjusted and adjusted for the conveyance speed of a conveyance means.

  The bunker 4 temporarily accommodates the mixed fuel composed of massive coal and biomass fuel before being supplied to the pulverized coal machine 3. The bunker 4 extends in the vertical direction and includes an opening provided at a lower end portion and a coal supply pipe extending from the opening, and supplies coal to the pulverized coal machine 3 through the coal supply pipe.

  The pulverized coal machine 3 is provided below the bunker 4. The pulverized coal machine 3 is a mill method for obtaining pulverized coal by grinding coal. The pulverized coal machine 3 has a roller for crushing coal inside, and a motor on which a roller is arranged is rotated to grind and crush the coal.

Next, the operation of the fuel supply facility 100 according to the embodiment of the present invention will be described.
Biomass fuel is directly carried into the temporary receiving area 1 from the vehicle 11. Biomass fuel is temporarily received in the temporary receiving area 1. Biomass fuel has a heat of 30 ° C. to 40 ° C. by fermentation when it is accepted in the provisional receiving area 1. The biomass fuel is supplied to the supply port of the screw 71 arranged in the temporary receiving area 1 and is sent out while the supply amount is adjusted by the screw 71. The fed biomass fuel is measured by a quantitative feeder 72 provided at the other end of the screw.

  Biomass fuel is supplied to the biomass supply conveyor 10 via the quantitative feeder 72. The biomass supply conveyor 10 has a proximal end disposed on the delivery mechanism 7 side and a terminal end disposed on the belt conveyor 20 side. The biomass fuel is conveyed by the biomass supply conveyor 10 and supplied onto the belt conveyor 20. From this provisional acceptance, the biomass fuel is conveyed by the biomass supply conveyor 10 to be supplied to the belt conveyor 20 and mixed with the coal within 24 hours. The biomass fuel supplied to the temporary receiving area 1 is mixed with coal within 24 hours without being stored.

  Bulk coal before pulverization is stored in the coal storage area 2. Coal is conveyed to the bunker 4 by a belt conveyor 20 extending from the coal storage area 2. As the belt conveyor 20 moves, the coal placed on the belt conveyor 20 moves. The end of the biomass supply conveyor 10 is arranged upstream of the belt conveyor 20 and vertically above the belt conveyor 20, and the biomass fuel conveyed by the biomass supply conveyor 10 is on the belt conveyor 20 that is conveying coal. Falls onto the ground, sprinkled on the coal and mixed with the coal. The belt conveyor 20 is provided so as to have a length of 50 m or more and 500 m or less from the base end portion on the coal storage area 2 side to the terminal end portion on the bunker 4 side. For this reason, while coal and biomass fuel are moving on the above-mentioned distance in a state where they are placed on the belt conveyor 20, the mixing is promoted with the vibration of the belt conveyor.

  Biomass fuel is appropriately dried by the heat of fermentation. Further, the biomass fuel is in a state suitable for combustion by further advancing fermentation and drying by agitation by the delivery mechanism 7 and vibration of the conveying means. Therefore, the agitation by the delivery mechanism 7 and the conveyance by the conveying means also serve as a biomass fuel drying step. The coal and biomass fuel before pulverization are mixed on the belt conveyor 20 in advance before being supplied to the bunker 4 to become a mixed fuel.

  For example, when the daily supply amount of coal is 4,000 t or more and 8,000 t or less, the mixed fuel has a biomass fuel supply amount of 60 t to 120 t. It becomes possible to supply the fuel at 3 mass% or less. In addition, even when the supply amount of biomass fuel per day is 160 t, when the supply amount of coal per day is 6,000 t or more and 8,000 t or less, the biomass fuel is 3% by mass with respect to coal. It becomes possible to supply below. The biomass fuel is preferably adjusted so that it is always supplied in an amount of 3% by mass or less based on coal.

As an example, Table 1 shows the relationship between the supply amount of coal and biomass fuel and the mixed firing rate. The values shown in Table 1 are the mixed firing rates when the number of bunkers 4 is 10 and the operation time of the belt conveyor 20 is 8 hours per day.

  The amount of coal to be supplied and the time for supplying coal to the bunker 4 and the pulverized coal machine 3 are determined as a coal transfer plan according to the amount of power generation demand of the coal-fired power plant. And based on the coal transmission plan, the mixing amount and mixing time of the biomass fuel are determined as the mixing plan. The mixing of biomass fuel and coal is performed based on a mixing plan.

  If it demonstrates using Table 1, the coal feeding time will be 8 hours per day, and the amount of coal feeding will be determined as a coal feeding plan between 4,000 t and 8,000 t. Based on this coal transfer plan, for example, the amount of biomass fuel mixed per day is determined between 60 t and 120 t (in the case of coal transfer amount of 6,000 t to 8,000 t, biomass fuel It is also possible to supply 160 t). Moreover, when the coal feeding time is 8 hours per day, the mixing time of biomass fuel per day is 8 hours or less per day. The biomass fuel mixing time does not exceed the coal delivery time. Thus, a mixing plan is determined by the mixing amount and mixing time of biomass fuel. For example, on the basis of a coal transfer plan in which coal is sent for 8,000 t per day for 8 hours, a mix plan is determined in which the mixing amount of biomass fuel is 100 t per day and the mixing time is 8 hours per day.

  Further, by determining the mixing amount and mixing time of the biomass fuel, the rotational speed of the screw 71 in the delivery mechanism in the receiving area 1 and the supply amount by the quantitative feeder 72, the transport speed of the biomass supply conveyor 10, and / or the belt conveyor The conveyance speed of 20 is adjusted. In the case of the above example, the biomass fuel is adjusted to be supplied at 12.5 t per hour. For example, the belt conveyor 20 is not operated continuously for 8 hours, but is operated for 2 hours, stopped for 30 minutes, further operated for 2 hours, stopped for 30 minutes, and further operated for 1.5 hours. It is preferable to provide a stop period, such as inspecting and repairing the equipment and operating for 2.5 hours.

  The maximum amount of biomass fuel received per day is determined by the coal transmission plan and the mixing plan so that biomass fuel can always supply 3% by mass or less to the coal. And within 24 hours from acceptance to mixing, biomass fuel is used up in a short period of time.

  Coal and biomass fuel are mixed on the belt conveyor 20 before reaching the bunker 4 and supplied to the bunker 4. The mixed fuel mixture is supplied to the pulverized coal machine 3 from an opening provided at the lower end of the bunker 4. The pulverized coal machine 3 grinds the mixed fuel to a size suitable for combustion, and supplies it to a boiler (not shown) that burns the mixed fuel.

According to this embodiment, the following effects are produced.
After the biomass fuel was received in the temporary receiving area 1, the coal and the biomass fuel were mixed within 24 hours without being stored in a silo or the like. For this reason, biomass fuel is clogged in the discharge port of the silo, and it does not take time and effort for cleaning and inspection. Moreover, even when the types and dimensions of the biomass fuel are different, there is no need to maintain and manage silos according to the types and dimensions, and there is no equipment cost, and it is possible to respond flexibly.

  After measuring the amount of biomass fuel delivered by the delivery mechanism 7, the biomass fuel and coal are mixed by the biomass supply conveyor 10 and / or the belt conveyor 20 at a predetermined conveying speed, and the biomass fuel delivery amount and / or the belt conveyor 20 The mixing ratio of biomass fuel and coal was adjusted according to the conveyance speed. For this reason, the mixing amount of the biomass fuel with respect to coal can be adjusted easily. In addition, since the temporary acceptance area 1 is a flat ground into which the vehicle 11 can directly enter, there is a concern about moisture fluctuation of the biomass fuel due to weather, but the biomass fuel has a temperature of 30 ° C. to 40 ° C. due to fermentation. ing. Therefore, drying can be performed using this temperature. That is, the biomass fuel is stirred by the screw 71 of the delivery mechanism 7 and supplied to the biomass supply conveyor 10 by the quantitative feeder 72. Moreover, the belt conveyor 20 is provided so that it may become 50 m or more and 500 m or less in length. In this way, while being stirred by the delivery mechanism 7 and then transported and mixed while receiving vibrations from the biomass supply conveyor 10 and the belt conveyor 20 having a predetermined length or more, drying of the biomass fuel also proceeds at the above temperature. For this reason, biomass fuel will be in the state more suitable for combustion. And the drying process of this biomass fuel can be performed on the flat ground into which the vehicle 11 can directly enter the temporary receiving area 1. As described above, the present invention is also characterized in that the biomass fuel receiving facility can be simplified by utilizing the thermal properties of the biomass fuel itself.

  The biomass fuel mixed with the coal was always 3% by mass or less based on the coal. For this reason, even if the mixed fuel obtained by mixing coal and biomass fuel with the mill type pulverized coal machine 3 is pulverized, the biomass fuel is light so that it moves upward in the pulverized coal machine 3 and pulverizes the biomass fuel. Problems that occur in the pulverized coal machine 3, such as being unable to be performed or adhering to the inside of the pulverized coal machine 3, are less likely to occur, and the mixed fuel can be pulverized without placing a burden on the pulverized coal machine 3. In addition, as a result of the dry biomass fuel being mixed with coal as described above, the moisture content of the coal is also adjusted, so the mixed fuel is less likely to clog the coal supply pipe between the bunker 4 and the pulverized coal machine 3, and the coal Even when grinding with the roller of the pulverized coal machine 3, it is possible to effectively prevent a decrease in suitability due to an increase in moisture and to enable stable pulverization.

  Based on the coal transfer plan from the coal yard to the coal bunker determined by the coal transfer time and amount, the biomass fuel mixing plan determined by the biomass fuel mixing time and amount is determined. It was decided to mix biomass fuel and coal based on the mixing plan. For this reason, it can plan so that mixing with coal can be performed within 24 hours from provisional receipt.

  It was decided to determine the maximum amount of biomass fuel received per day according to the above coal transmission plan and mixing plan. For this reason, it can adjust easily so that the mixing amount of the biomass fuel with respect to coal can be 3 mass% or less.

1 Temporary receiving area 2 Coal storage area 4 Bunker 7 Delivery mechanism 10 Biomass supply conveyor (conveyance means)
11 Vehicle 20 Belt conveyor (conveyance means)
100 Fuel supply equipment

Claims (4)

In a fuel supply facility of a coal-fired power plant that uses biomass mixed fuel obtained by mixing biomass fuel with coal,
A provisional receiving area for temporarily receiving the biomass fuel;
The provisional receiving area is a flat area where vehicles can directly enter,
The fuel supply facility, the biomass fuel, a delivery mechanism for delivering a certain amount from the temporary receiving area,
A conveying means for mixing and conveying the biomass fuel and the coal fed from the feeding mechanism;
After weighing the amount of the biomass fuel sent out by the delivery mechanism, the biomass fuel and the coal are mixed by the transport means of a predetermined transport speed,
Adjust the mixing rate of the biomass fuel and the coal according to the amount of biomass fuel delivered,
The method for producing a biomass mixed fuel, wherein the coal and the biomass fuel are mixed within 24 hours from provisional acceptance in the provisional acceptance area. The biomass fuel to be mixed with the coal, always producing method of biomass mixed fuel according to claim 1, 3 mass% or less with respect to the coal. The fuel supply facility includes a coal storage area for storing coal, and a bunker for temporarily storing mixed fuel,
Based on the coal delivery plan from the coal storage area to the bunker, determined by the coal delivery time and the amount of coal delivered,
Determining the biomass fuel mixing plan determined by the mixing time and amount of the biomass fuel;
The manufacturing method of the biomass mixed fuel of Claim 2 which mixes the said biomass fuel and coal based on the said mixing plan. The method for producing a biomass mixed fuel according to claim 3 , wherein a maximum amount of the biomass fuel received per day is determined by the coal feeding plan and the mixing plan.

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