JP2015117926A - Dryer using both fossil fuel and biomass fuel for firing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a kerosene fired boiler capable of using biomass fuel as well as fossil fuel in a dryer for drying a drying target using the fossil fuel and the biomass fuel, the dryer capable of ensuring short resident time of the drying target in a dry chamber and drying the drying target with excellent fuel economy in a short time.SOLUTION: In a combustion system firing kerosene as fossil fuel and woodchip pellets as biomass fuel, a combustion burner using the biomass fuel is attached to a combustor for a kerosene fuel burner in the combustion furnace. Flue gas generated by combustion in the combustor using the biomass fuel by a weight ratio of two to five times as high as that of the kerosene fuel is supplied from a flue gas channel to a hot blast heat source. Hot blast at 50°C to 90°C is supplied from the hot blast heat source to a heating target located in an upper portion of a circulation shelf box dryer either by a blower by implementing heat exchange or by partially directly supplying the hot blast from an entire lower portion of the circulation shelf dryer.

Description

The present invention relates to a drying apparatus for burning a fossil fuel of kerosene and biomass fuel of wood chip pellets to dry an object to be dried. The present invention relates to a drying apparatus for drying an object to be dried with biomass fuel of kerosene and wood chip pellets in order to prevent a reduction in combustion efficiency when burning biomass fuel with a kerosene-fired boiler.

In recent years, biomass fuels using biomass materials derived from organic substances such as plants have attracted attention as alternative fuels to fossil fuels such as heavy oil. Biomass fuels include biohydrogen and bioethanol that are obtained from a biomass material through chemical treatment in order to obtain combustion substances. In addition, there are RDF (Refuse Delivered Fuel) formed by mixing waste plastics and solid fuel formed by substantially molding only the biomass material in order to directly burn the biomass material.

As biomass materials used for such biomass fuel, woody materials such as sawdust, wood chips, thinned wood and pruned wood, agricultural materials such as rice straw, rice husks, weeds and bagasse, and waste such as construction waste There are system materials. In order to use these biomass materials for biomass fuel, it is necessary to dry them sufficiently to reduce the water content.

In order to dry the biomass material, conventionally, for example, a rotary drying apparatus as disclosed in Patent Document 1 is used. This drying apparatus has a drying chamber in a cylindrical furnace that is horizontally placed and rotationally driven, and the material to be dried supplied from one end side of the drying chamber is stirred by the slow rotation of the drying chamber. It is moved to the other end side.

Biomass fuel is a plant-based fuel other than fossil fuel, and its type is not limited to a specific one, but in particular, all waste materials and sludge that come out as forest and daily recycling, as well as secondary processed products, etc. A plant-based fuel having a calorific value capable of becoming a fuel containing odor. It is rarely used industrially in terms of heat.

Conventionally, a stoker furnace or a fluidized bed type combustion furnace has been mainly used for combustion of biomass fuel. In this case, a method of supplying biomass fuel as it is without drying biomass fuel has been adopted. When biomass fuel is supplied to a furnace without drying in advance and burned, combustion efficiency deteriorates due to energy loss due to sensible heat and latent heat due to moisture contained in the biomass fuel. However, the combustion efficiency of these furnaces is usually as low as about 20% to 30%, and the decrease in combustion efficiency due to the introduction of moisture into the furnace was negligible.

In recent years, the initiative to use biomass fuel as renewable energy has become active (see Patent Document 1). In particular, in a boiler for power generation, it is an essential condition to generate power while maintaining high efficiency when burning biomass fuel.

In a conventional coal-fired boiler furnace for power generation that is provided with a burner that is supplied to the furnace with combustion air and combusted after being finely pulverized, when biomass fuel is supplied to the furnace as a secondary fuel and burned, It is conceivable to finely pulverize and supply to a boiler furnace in an air stream.

The boiler furnace is provided with a plurality of burners in the height direction of the furnace and a plurality of burners in the width direction on the wall surface of the furnace facing each other, and on the downstream side of the burner, the position facing the furnace similar to the burner An air outlet OFA (Over Filing Airport) is provided on the wall surface.

The combustion air was pressurized by a forced draft fan FDF (Force Draft Fan), heated to about 350 ° C. by an air heater (heat exchanger), and then provided corresponding to each burner stage. It is supplied to a wind box for combustion air and distributed to a plurality of burners for each burner stage. Thereafter, the combustion air is given a speed and swirl strength necessary for high-efficiency combustion, and a method is proposed in which the combustion air is jetted and supplied from the burner throat facing the furnace and mixed with the pulverized coal fuel to burn. (See Patent Document 2).

JP 2006-84024 A Japanese Patent Laid-Open No. 2002-241761

In a drying apparatus using a kerosene-burning furnace, sufficient drying operation is not performed due to a rise in drying costs due to a rise in kerosene. If biomass fuel can be used in combination with a kerosene-burning combustion device, it is effective in terms of fuel costs. Until now, it has been difficult to attach a biomass fuel burner to a kerosene burner.

In an apparatus for drying an object to be dried as a fuel using kerosene fossil fuel and wood pellet pellet biomass fuel, pretreatment of moisture contained in the biomass fuel becomes a problem. When only biomass fuel is used as fuel, for example, if it is a biomass fuel with a moisture content of 50%, the boiler efficiency is calculated to be reduced by 5%.
Since it is a disadvantageous condition for realizing the co-firing of biomass fuel, the establishment of technology to prevent moisture from being brought into the boiler furnace is a condition to be solved when realizing co-firing of biomass fuel.

The subject of this invention is providing the kerosene fired boiler which uses the biomass fuel obtained by the biomass fuel drying apparatus which uses biomass fuel for the combustion furnace of kerosene cooking and uses it as a fuel, and the drying apparatus of the said biomass fuel.

Since the material to be dried is dried by stirring at a relatively low speed in high-temperature air, the drying time is relatively long, about 5 to 15 minutes. Along with this, there is a problem that the residence time of the material to be dried in the drying chamber is long, and the dryness is not stable due to the difference in the amount of water contained in the material to be dried supplied into the drying chamber.

Further, in an environment where the object to be dried is slowly moved into high-temperature air, the object to be dried with a small amount of water may be ignited. Moreover, since the to-be-dried material is a comparatively flexible biomass material of agricultural material, since it is comprised with a comparatively long flexible fiber, it is easy to become a lump with a entanglement of a component. The to-be-dried material that has become agglomerated has a problem that the inside is difficult to dry, and thus the degree of drying varies greatly, and handling is troublesome.

In addition, depending on the heating burner that is attached to the drying chamber, it takes time from the start of operation until it stabilizes in the dry state. For this reason, once the operation is started, it is difficult to stop the burner and the operation continues for a relatively long time. There is a problem that there is a lot of wasted fuel consumption. Furthermore, since the rotary drying apparatus is configured to rotate the entire drying chamber, it is relatively easy to break down and the apparatus configuration is complicated.

Therefore, the problem of the present invention is that the residence time of the material to be dried in the drying room is short, the material to be dried can be dried with a stable degree of dryness, there are few failures, and the apparatus configuration is relatively simple. There is an object of providing a drying apparatus suitable for drying an object to be dried using biomass fuel in a kerosene-burning combustion furnace.

In a combustion apparatus that burns kerosene as fossil fuel and biomass fuel of wood pellets in a combustion furnace, a combustion burner using biomass fuel is attached to the combustor for the kerosene fuel burner in the combustion furnace, and the kerosene fuel is The hot air heat source of the flue gas generated by the combustor supplied with a weight ratio of 2 to 5 times the biomass fuel is exchanged by blowing fresh air from the blower heat exchange and partially by directly introducing the flue gas. Circulation that allows hot air of ˜90 ° C. to be dried uniformly from the entire lower part of the drying chamber to the object to be dried placed on the upper circulation hole shelf or net plate This is a combined cooking and drying device of fossil fuel and biomass fuel, which is a mold box drying device.

Combustion exhaust gas obtained by supplying a total of 6000 to 10000 Kcal / kg of calorie fuel of kerosene fossil fuel and wood pellet pellet fuel into the combustion furnace is divided into 5 to 20 m3 drying chambers in two upper and lower stages. Partition and ventilate through a flow-type box-type drying device in which a shelf or net plate having a hot air flow hole of 1 to 5 mm is installed in the partition part, and can generate hot air that can be maintained in a temperature range of 50 to 90 ° C. A combustion furnace with a combined burner of kerosene and biofuel is installed.

A drying device that dries an object to be dried with hot air in a drying chamber of a circulation type box-shaped device, and generates hot air for drying the object to be dried in a combustion furnace having a combined combustor of kerosene and biofuel, A shelf with hot air circulation holes to distribute the hot air evenly by dividing the circulation type shelf type box-shaped device of the drying chamber into two stages, with the lower part as the hot air supply space part and the upper part as the drying object loading part. Alternatively, it is partitioned by a net plate, and includes means for uniformly supplying hot air upstream from the lower stage, and means for controlling the degree of drying of the object to be dried by the temperature and amount of hot air supplied by the hot air supply means.

In the drying apparatus, the hot air supply means is formed by each combustor that generates hot air by combusting a combustor that uses kerosene fossil fuel and wood pellet pellet biomass fuel in front of the combustion furnace. Each of the three combustors includes a fuel supply unit that supplies kerosene fuel or biomass fuel, a blower that pumps the combustion air supplied into the combustor in each combustion furnace, and the fuel supply unit. A control unit for the combustor that adjusts the temperature and the amount of hot air generated by each combustor by adjusting the amount of each fuel supplied and the amount of air blown by the blower.

A combustor for supplying kerosene fossil fuel and wood pellet pellet biomass fuel into the combustion furnace is disposed on the front side of the combustion furnace, and combustion exhaust gas generated by combustion in the combustor is placed in the combustion furnace. A hot air source supplied from a flue gas flow path in an installed U-shaped bent pipe is sent directly from an air flow by pumping outside air from a blower and indirectly heat-exchanged, and directly from a combustion exhaust chimney Part of the combustion exhaust gas is introduced into the hot air supply space at the lower stage of the circulation type box-type device in the drying chamber.

The to-be-dried material is one of woody material, agricultural material, food material and waste material, and contains 30% by weight or more of water, and wood fuel is mainly used as biomass fuel. The fuel to be combusted in the combustor is a pellet-like biomass system with a length of 3 to 10 mm, and the dried agricultural material and waste material are added to 50% or less. And pellets mixed with crushed wood material.

Using the flue gas generated by the combustion in the biomass fuel furnace in the kerosene cooking furnace, the usability of biomass fuel has been improved with fuel efficiency.

The combustion exhaust gas temperature at the inlet of the dryer can be maintained at 50 to 90 ° C.
The exhaust gas used to dry the biomass fuel is recycled to the boiler, so there is no need for a special heat source for drying the biomass fuel, and there is no need for a treatment facility for exhaust gas containing VOC (volatile toxic compounds) after drying. And an effective woody biomass fuel combustion boiler system can be constructed.

According to the said form, the to-be-dried object can be dried, without consuming fossil fuels, such as kerosene, by forming the said hot air production | generation means with the burner which produces | generates a hot air using biomass fuel. Therefore, when the material to be dried is a biomass material for biomass fuel, by preventing consumption of fossil fuel in the production of biomass fuel, and by adjusting the fuel supply amount of the fuel supply means and the blower amount of the blower The temperature and air volume of the hot air generated by the combustor can be finely adjusted, and therefore the drying capacity of the drying device can be finely adjusted.

The said combustor is arrange | positioned at the outer peripheral side of the said combustion furnace, can supply sufficient oxygen in a combustion furnace, and can burn biomass fuel completely. In this way, the combustion gas produced by complete combustion of the biomass fuel is generated as hot air, so that hot air with less ash components and unburned components could be supplied to the drying chamber.

According to the said embodiment, the biomass material containing either woody material, agricultural material, and waste material can be dried to the stable dryness, without making it ignite. In particular, woody materials and agricultural materials having a relatively high water content can be effectively dried.

It is a general view showing a kerosene and fossil fuel and wood pellet pellets combined biomass fuel drying apparatus. It is a top view which shows the structure in the heat exchange with a biomass fuel cooking combustor, a combustion furnace, and an air blower. FIG. 3 is a cross-sectional view of a circulation type shelf-type box device divided into two stages, a lower part of a hot air supply space part, and an upper part of a drying object storage part. It is sectional drawing of the biomass combustion furnace of a kerosene and fossil fuel and wood pellet pellet combined use cooking and drying apparatus. A: Plan view B: Cross section, C: Front view

Fig. 1 is an overall view showing a fossil fuel and wood pellet pellet biomass fuel combined drying apparatus, Fig. 2 is a plan view showing a configuration of heat exchange between a biomass fuel cooking combustor, a combustion furnace, and a blower. The distribution shelf type box-shaped device is divided into two stages, the lower part is shown in the hot air supply space part, and the upper part is shown in the figure of the drying object storage part.

As shown in FIG. 1, in a combustion apparatus for burning kerosene as a fossil fuel and biomass fuel of wood chip pellets in a combustion furnace, a combustion burner combustor using biomass fuel is used as the burner for the kerosene fuel burner in the combustion furnace. A hot wind heat source supplied from the combustion exhaust gas flow path to the combustion exhaust gas generated by combustion in the combustion furnace used at a weight ratio of 2.25 times the biomass fuel to the kerosene fuel is installed and blown into the drying chamber A circulation type box-shaped device for drying an object to be dried.

Combustion exhaust gas obtained by supplying a total of 256,000 Kcal / kg calorie fuel of kerosene fossil fuel (90 L) and wood pellet pellet biomass fuel (707 kg) (ratio 1: 3) to the combustion furnace is 20 m 3. Was a combustion furnace capable of generating hot air capable of maintaining the drying chamber in a temperature range of 60 to 75 ° C. As the biomass fuel, woody material pellets mainly using waste wood from dried wood were used.

As shown in FIG. 3, a drying apparatus for drying coconut grass as a material to be dried with hot air as shown in FIG. did. A hot air generating means for generating hot air for drying the dried material of the grass and supplying it from the upstream side of the drying chamber; and a dried material supply means for juxtaposing the dried grass material on the upper side of the drying chamber; Accordingly, a control unit for controlling the drying degree of the object to be dried is provided on the lower side of the means by adjusting the temperature and amount of hot air by the hot air generating means and the supply amount of the object to be dried.

In the drying apparatus, the hot air generating means is a burner that generates hot air by burning one kerosene fossil fuel and two wood chip pellet biomass fuels in a total of three combustion furnaces as shown in FIG. The burner is formed by a fuel supply means for supplying kerosene fuel and biomass fuel to the combustion furnace, a blower for pumping the combustion air supplied to the burner in each combustion furnace, and the fuel supply means. The burner control part which adjusts the supply amount of each fuel of this and each blast amount of the said air blower, and adjusts the temperature and air volume of the hot air which each burner produces | generates.

Burners that supply kerosene fossil fuel and wood pellet pellet biomass fuel into the combustion furnace are arranged on the front side of the combustion furnace, and the supply of fuel and air is controlled by the air flow pumped from each blower. Combustion was enhanced, and the combustion gas was applied to the heat exchanger from the air chamber into the combustion furnace and discharged from the chimney.
An air stream was sent from the blower to the heat exchanger and sent to the drying chamber.

It was used for drying licorice as an object to be dried. The bundles of cut grass were placed on a shelf and dried with hot air in the range of 65 to 75 ° C. for 16 hours. As a result, 10% or less of dried licorice product was obtained. Compared to burning with kerosene alone, the fuel was saved by about 42%.

In the combustion apparatus for burning kerosene as fossil fuel and biomass fuel of wood chip pellets in a combustion furnace as in Example 1, a combustion burner using biomass fuel is attached to the combustor for the kerosene fuel burner in the combustion furnace. The hot air heat source supplied from the combustion exhaust gas flow path to the combustion exhaust gas generated by the combustion in the combustion furnace used at a weight ratio of 4 times that of kerosene fuel and biomass fuel is blown into the drying chamber, and the material to be dried is removed. It is a circulation type box-shaped device to be dried.

Combustion exhaust gas obtained by supplying a total of 7000 Kcal / kg fuel of kerosene fossil fuel and wood pellet pellet biomass fuel (ratio 1: 4) into the combustion furnace has a drying chamber of 70 m2 It was a combustion furnace capable of generating hot air that can be maintained in a temperature range of 75 ° C. As the biomass fuel, a woody material pellet in which the waste fungus bed at the time of waste wood from dried wood was partially mixed was used.

As shown in FIG. 3, a drying apparatus that dries hay as a material to be dried with hot air in a drying chamber. Made uniform. A hot air generating means for generating hot air for drying the dried material of the grass and supplying it from the upstream side of the drying chamber; and a dried material supply means for juxtaposing the dried grass material on the upper side of the drying chamber; Accordingly, a control unit for controlling the drying degree of the object to be dried is provided on the lower side of the means by adjusting the temperature and amount of hot air by the hot air generating means and the supply amount of the object to be dried.

In the drying apparatus, the hot air generating means is formed of a burner that generates hot air by burning one kerosene fossil fuel and three wood chip pellet biomass fuels in a total of four combustion furnaces. The fuel supply means for supplying kerosene fuel and biomass fuel to the combustion furnace, the blower for pumping the combustion air supplied to the burner in each combustion furnace, and the supply of each fuel by the fuel supply means The burner control part which adjusts the temperature and the air volume of the hot air which each burner produces | generates by adjusting quantity and each ventilation volume of the said air blower was provided.

Burners that supply kerosene fossil fuel and wood pellet pellet biomass fuel into the combustion furnace are arranged on the front side of the combustion furnace, and the supply of fuel and air is controlled by the air flow pumped from each blower. Combustion was enhanced, and the combustion gas was applied to the heat exchanger from the air chamber into the combustion furnace and discharged from the chimney.
An air flow was sent from the blower to the heat exchanger, and it was taken out in front of the chimney and a part of the combustion gas was added to the supply air flow and sent to the drying chamber.

It was used for drying licorice as an object to be dried. The bundles of cut grass were placed on a shelf and dried with hot air at 70 to 75 ° C. for 14 hours. As for the cocoon grass, 70% was 15%, and a dry cocoon product was obtained. Compared to burning with kerosene alone, the fuel was saved by about 55%.

DESCRIPTION OF SYMBOLS 1 Kerosene fuel burner 2 Biomass fuel burner 3 Pellet tank 4 Screw conveyor for fuel supply 5 Hot air generator 6 Drying device (box type drying device)
7 Heat Exchanger 8 Chimney 9 Suction Fan 10 Combustion Furnace 11 Blower 12 Dried Object Support Shelf 13 Dried Object 14 Hot Air Path (Hot Air Supply Space)
15 Kerosene tank 16 Flame 17 Burner nozzle 18 Air introduction port 19 Bogie 20 Discharge port 21, 22 Control panel 23 Pellet supply port

Claims (6)

In a combustion apparatus that burns kerosene as fossil fuel and biomass fuel of wood pellets in a combustion furnace, a combustion burner using biomass fuel is attached to the combustor for the kerosene fuel burner in the combustion furnace, and the kerosene fuel is The hot air heat source of the combustion exhaust gas generated by the combustor supplied 2 to 5 times by weight with the biomass fuel is exchanged by blowing fresh air from the blower in a heat exchange manner and partially by directly introducing the combustion exhaust gas. Circulation that allows hot air of ˜90 ° C. to be dried uniformly from the entire lower part of the drying chamber to the object to be dried placed on the upper circulation hole shelf or net plate A combined cooking and drying device of fossil fuel and biomass fuel, characterized in that it is a mold box drying device. Combustion exhaust gas in which a total of 6000 to 10000 Kcal / kg calorific fuel of kerosene fossil fuel and wood pellet fuel is supplied into the combustion furnace is divided into two upper and lower stages of a drying chamber of 5 to 20 m3, Kerosene and bio that can generate hot air that can be maintained in a temperature range of 50 to 90 ° C by passing through a circulation type box-type drying device that has a shelf or net board with a hot air circulation hole of 1 to 5 mm in the partition. 2. The combined cooking and drying apparatus for fossil fuel and biomass fuel according to claim 1, wherein a combustion furnace having a combined fuel combustor is installed. A drying device that dries an object to be dried with hot air in a drying chamber of a circulation type box-shaped device, and generates hot air for drying the object to be dried in a combustion furnace having a combined combustor of kerosene and biofuel, A shelf with hot air circulation holes to distribute the hot air evenly by dividing the circulation type shelf type box-shaped device of the drying chamber into two stages, with the lower part as the hot air supply space part and the upper part as the drying object loading part. Or it is partitioned by a net plate, and comprises means for uniformly supplying hot air upstream from the lower stage and means for controlling the degree of drying of the object to be dried by the temperature and amount of hot air by the hot air supply means. A combined cooking and drying apparatus of the fossil fuel and the biomass fuel according to claim 1 or 2, wherein the fossil fuel and the biomass fuel are combined. In the drying apparatus, the hot air supply means is formed by each combustor that generates hot air by combusting a combustor that uses fossil fuel of kerosene and biomass fuel of wood chip pellets in front of the combustion furnace, 1 to 3 combustors include fuel supply means for supplying kerosene fuel or biomass fuel, a blower for pumping combustion air supplied to the combustor in each combustion furnace, and the fuel supply means. 2. Combustor control means for adjusting the temperature and air volume of hot air generated by each combustor by adjusting the supply amount of each fuel and the air flow rate of each of the blowers. A combined cooking and drying apparatus of the fossil fuel and the biomass fuel according to any one of claims 3 to 4. A combustor for supplying kerosene fossil fuel and wood pellet pellet biomass fuel into the combustion furnace is disposed on the front side of the combustion furnace, and combustion exhaust gas generated by combustion in the combustor is placed in the combustion furnace. A hot air source supplied from a flue gas flow path in an installed U-shaped bent pipe is sent directly from an air flow by pumping outside air from a blower and indirectly heat-exchanged, and directly from a combustion exhaust chimney The fossil fuel and the biomass fuel according to any one of claims 1 to 4, wherein a part of the combustion exhaust gas is introduced into a hot air supply space at a lower stage of the circulation type box-shaped device in the drying chamber. Combined cooking and drying equipment. The to-be-dried material is any of woody material, agricultural material, food material and waste material, and contains 30% by weight or more of moisture, and the biomass fuel is mainly wood waste. The fuel to be combusted in the combustor is a biomass wood material in the form of pellets of 3 to 20 mmφ and length of 3 to 20 mm, and 50% by volume or less of dried agricultural material and waste material The combined cooking and drying apparatus for fossil fuel and biomass fuel according to any one of claims 1 to 5, which is a biomass wood pellet mixed with a crushed material of wood material.

Images