JP2007238706A - Gasification oven - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dissolve the bridging phenomenon of a biomass in an oven by an inexpensive means without requiring excessive maintenance. <P>SOLUTION: The bridging phenomenon is solved without requiring excessive maintenance by throwing-in a multiple number of small spheres G formed by a metal or ceramics having a larger size than the gap of fire grate 5 at the bottom of an oven, from upper direction into the oven from a constant feeding machine 10, when the bridging phenomenon of the biomass A is developed in the oven, and after solving the bridging phenomenon, sliding the bottom part 5a of the fire grate 5 in horizontal direction, discharging the small spheres G accumulated on the fire grate 5 from a discharging tube 8 by a screw conveyer 9 so as not to disturb combustion residue F falling through the fire grate 5, also separating the discharged small spheres G from combustion residue F by a separating unit 11 and conveying for returning the spheres to a hopper 10a of the constant-feeding machine 10 through a conveying tube 12 to make them repeatedly usable. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a gasification furnace that generates biomass gas by gasifying a biomass as a raw material.

  In a gasification furnace using biomass as a raw material, biomass is supplied from above into a vertical furnace with a raw material supply port provided at the top and a grate at the bottom, and the supplied biomass is supplied in the furnace. In some cases, gasification reaction is performed while moving to the respective zones of drying, pyrolysis, oxidation, and reduction in order downward, and biomass gas generated by this gasification reaction is discharged (for example, Patent Document 1). reference).

  In such a biomass gasification furnace, biomass having a low bulk density causes a bridging phenomenon in the furnace, and the smooth movement of the biomass downward is hindered, which may hinder stable operation. In the device described in Patent Document 1, stirring means is provided in the furnace to prevent the bridging phenomenon of biomass.

  Biomass gasification furnaces are pre-heated by laying multiple layers of refractory balls such as metal balls or ceramic balls on the bottom grate at the start of operation to shorten the operation start-up time. is there. This gasification furnace can shorten the operation start-up time, but the refractory balls laid in layers on the grate hinder combustion residues falling from the grate.

JP 2005-146188 A JP 2002-285172 A

  The biomass gasification furnace described in Patent Document 1 can eliminate the biomass bridging phenomenon by stirring the inside of the furnace with stirring means, even if biomass with a low bulk density is used as a raw material. Since it is necessary to provide it, there is a problem that the equipment cost increases and maintenance is troublesome.

  Therefore, an object of the present invention is to be able to eliminate the bridging phenomenon of biomass in the furnace without requiring an inexpensive and extra maintenance.

  In order to solve the above-described problems, the present invention supplies biomass as a raw material from above into a vertical furnace provided with a raw material supply port at the top and a grate at the bottom. In a gasification furnace that discharges biomass gas generated by the gasification reaction while moving biomass downward in the furnace, a plurality of metal or ceramics formed larger than the gap of the grate Of the small spheres from above into the furnace, means for taking out the small spheres that have been put into the furnace and accumulated on the grate, and the small spheres taken out to the outside to the charging means The structure provided with the means to carry back was employ | adopted.

  That is, a charging means for charging a plurality of small spheres made of metal or ceramics larger than the gap of the grate into the furnace from above, and taking out the small spheres charged in the furnace and accumulated on the grate to the outside And a means for returning and transporting the small spheres taken out to the outside to the charging means, and when a bridging phenomenon of biomass occurs in the furnace, the small spheres are thrown into the furnace from the top and bridged. After eliminating the phenomenon and eliminating the bridging phenomenon, take out the small spheres that accumulate on the grate to prevent it from interfering with the combustion residues falling from the grate, and return the globules taken out to the outside. It can be transported and used repeatedly, eliminating the need for extra maintenance at a low cost and eliminating the bridging phenomenon.

  At the start of the operation of the gasifier, the start-up time can be shortened by charging the plurality of small spheres onto the grate by the charging means and preheating these small spheres.

  The gasification furnace of the present invention has a charging means for charging a plurality of small spheres made of metal or ceramics larger than the gap of the grate into the furnace from above, and is charged into the furnace and collected on the grate. By providing means for taking out the small balls to the outside and means for returning the small balls taken out to the outside to the charging means, when the biomass bridging phenomenon occurs in the furnace, the small balls are removed from the top of the furnace. After eliminating the bridging phenomenon by introducing it into the inside, take out the small spheres that accumulate on the grate outside so as not to interfere with the combustion residue falling from the grate and to the outside Since the taken out small spheres are returned and transported and can be used repeatedly, it is possible to eliminate the bridging phenomenon without requiring extra maintenance at low cost.

  At the start of the operation of the gasifier, the start-up time can be shortened by charging the plurality of small spheres onto the grate by the charging means and preheating these small spheres.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, this gasification furnace is provided with a supply port 2 for biomass A in the upper part of a vertical furnace body 1, and an air supply pipe 3 for supplying combustion air B to the side wall and an ignition A burner 4 is provided, and a mortar-like grate 5 is provided at the bottom. The biomass A supplied from the supply port 2 and deposited in the furnace is gasified with the air B. The produced biomass gas C is discharged from a gas discharge port 6 provided on the lower side of the grate 5, and foreign matter D such as char and ash is removed by a cyclone 7, and then recovered as product gas E. The combustion residue F generated by the gasification reaction falls from the grate 5 and is discharged to the outside by the screw conveyor 9 from the discharge pipe 8 connected to the bottom.

  Above the furnace body 1, a fixed quantity feeder 10 is provided that supplies a small sphere G made of metal or ceramics and having a diameter larger than the gap of the grate 5 by several millimeters. When the phenomenon occurs, a plurality of small spheres G supplied from the quantitative feeder 10 are put into the furnace from above to eliminate the bridge phenomenon. The fixed quantity feeder 10 supplies the small sphere G into the furnace even at the start of operation, and the small sphere G put on the grate 5 is preheated by the burner 4 which is inclined downward. .

  The bottom portion 5a of the mortar-shaped grate 5 is slidable in the horizontal direction, and the small spheres G that accumulate on the grate 5 after the elimination of the bridge phenomenon and after the start of operation are taken out from the discharge pipe 8 to the outside by the screw conveyor 9. It is like that. The small sphere G discharged together with the combustion residue F by the screw conveyor 9 is separated from the combustion residue F by the sieve separator 11, transported back to the metering feeder 10 by the transport pipe 12, and is transported to the hopper 10a. Stored. The small spheres G stored in the hopper 10a are supplied again from the fixed quantity feeder 10 into the furnace when the bridge phenomenon occurs or when the operation is started, and are repeatedly used.

A longitudinal sectional view showing an embodiment of a gasification furnace

Explanation of symbols

A Biomass B Combustion Air C Biomass Gas D Foreign Material E Product Gas F Combustion Residue G Small Ball 1 Furnace 2 Supply Port 3 Air Supply Pipe 4 Burner 5 Grate 5a Bottom 6 Gas Discharge Port 7 Cyclone 8 Discharge Pipe 9 Screw Conveyor 10 Fixed quantity feeder 10a Hopper 11 Separator 12 Conveying pipe

Claims (2)

  A gasification reaction is performed by supplying biomass from above as a raw material into a vertical furnace with a raw material supply port at the top and a grate at the bottom, and moving the supplied biomass downward in the furnace. In the gasification furnace for discharging the biomass gas generated by this gasification reaction, a charging means for charging a plurality of small spheres formed of metal or ceramic larger than the gap of the grate into the furnace from above And a means for taking out the small spheres that have been thrown into the furnace and collecting on the grate to the outside, and a means for returning and feeding the small spheres taken out to the outside to the throwing means. Gasification furnace.   The gasification furnace according to claim 1, wherein at the start of operation of the gasification furnace, the plurality of small spheres are charged onto the grate by the charging means, and these small spheres are preheated.

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