Further aspects and advantages of the present invention will become better understood with reference to the description in association with the following Figures, in which similar references used in different Figures denote similar components, wherein:
With reference to the annexed drawings the preferred embodiment of the present invention will be herein described for indicative purpose and by no means as of limitation.
Referring first to
A feed hopper 10 is disposed vertically above the opening 7 and has a rotatable drive spindle 9 carrying a plurality of comminuting paddles 11; the hopper 10 has an outlet 13 feeding onto a rotating feed table 14 provided with a discharge station 15 selectively aligned with the opening 7 and the outlet 13. In use feedstock, namely the biomass, is fed into the hopper 10 wherein it is comminuted prior to delivery to the combustion zone 4.
Alternatively, as it would be obvious to one skilled in the art, the feedstock, typically fed from a conveyor (not shown), can be directed into the hopper 10 free of any spindle 9 and paddles 11, or even directly fed into the feed tube 6 through opening 7, without deviating from the scope of the present invention.
At the base of the combustion zone 4 there is provided a circular rotatable grate 20 the diameter of which is greater than the base dimension of the zone 4 which is spaced therefrom to provide a path in use for the centrifugal conveyance of incandescent biomass. The biomass located in the upper region of the combustion zone 4 is heated and dried by the heat generated by the incandescent biomass to form a pyrolysis zone. At the center of the grate 20 is a foraminous conical plenum chamber 22 for the introduction of air into the combustion zone 4, an air inlet pipe 24 being connected thereto and extending therefrom the exterior of the body 2. A drive shaft 26 for the grate 20 extends through the pipe 24 for rotating the grate. A solid waste collection area 30 is defined beneath the rotatable grate 20 and a discharge outlet 32 is provided for that area and leads to a removal station 34.
A secondary, normal combustion zone 40 is defined externally of the primary zone 4 and is provided with perforated air distributor tubes or sparge pipes 42 to provide air for the combustion.
Both the zones 4 and 40 are contained within a central cylindrical core 50, which is provided with suitable outlets 52 and 54 respectively for said zones, a gas discharge conduit 53 connecting the zone 4 to the outlet 52.
A gas mixing chamber 60 is defined between the core 50 and the wall of the body 2 at the exit from the zones 4 and 40 and in this chamber the gases arising from pyrolysis and the combustion zones are mixed. Thence the mixture of gases flows through into a heat exchange zone 59 including a tube bank 61 formed in the annular space between the core 50 and the wall of the body 2. In
In use comminuted poultry litter biomass is fed from the hopper 10 into the feed tube 6 of the combustion zone 4 and descends onto the grate 20 and forms a bed of biomass typically extending up into the tube as shown in order to prevent heat losses there through. The temperature of the zone 4 is initially raised to a level appropriate for the ignition of the biomass and air is provided through the plenum 22. The biomass is burned only at the bottom (lower region 5b) of the zone (smothered combustion) and that combustion energy allows the pyrolysis phenomenon in the biomass column thereabove (upper region 5a), and the hot gases of pyrolysis exit therefrom through the conduit 53 and the outlet 52 into the mixing chamber 60.
An incandescent layer or cake of biomass gradually radiates on the rotating grate 20 to pass from the pyrolysis zone 4 into the normal combustion zone 40 supplied with air through sparge pipes 42, the gas being generated passing through the outlet 54 into the mixing chamber 60 after providing more energy to the biomass in zone 4 for pyrolysis.
In the embodiment of
In the embodiment of
The baffles are provided to improve turbulence and simultaneously increase residence time of the gases to enhance heat transfer and the consumption of potentially noxious elements in the gases.
The present invention thus provides a relatively simple and yet effective means of disposing of a waste biomass product in a useful ‘green’ energy way, thus reducing the time and cost of conventional disposal.
Although the present invention has been described with a certain degree of particularity, it is to be understood that the disclosure has been made by way of example only and that the present invention is not limited to the features of the embodiments described and illustrated herein, but includes all variations and modifications within the scope and spirit of the invention as hereinafter claimed.
Benefit of U.S. Provisional Application for Patent Ser. No. 60/795,572, filed on Apr. 28, 2006, is hereby claimed.
Number | Date | Country | |
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60795572 | Apr 2006 | US |