Biomass gasification apparatus
A compact biomass gasification apparatus is capable of gasifying a wide variety of biomass materials, without regard to their size and/or the water content of those materials, and also capable of substantially removing the tar component generated in a gasification process. A biomass gasification apparatus primarily includes an externally heated rotary kiln-type thermal cracking unit ( 2 ) indirectly heating and thermally cracking a biomass material to generate a tar-containing pyrolysis gas and char from the biomass material, and a gasification unit ( 3 ) receiving the tar-containing pyrolysis gas and char from the thermal cracking unit ( 2 ) and thermally cracking the tar component in the pyrolysis gas and gasifying the char by an oxidation gas being introduced therein.
1. A biomass gasification apparatus comprising:
an externally heated rotary kiln thermal cracking unit that indirectly heats and thermally cracks a biomass material to generate a tar-containing pyrolysis gas and char from the biomass material, and
a gasification unit that receives the tar-containing pyrolysis gas and char from said thermal cracking unit, and thermally cracks the tar component in the pyrolysis gas and gasifies the char by an oxidation gas introduced therein, wherein said gasification unit comprises a tar component thermal cracking region in which the tar component is thermally cracked, a char gasification region in which the char is gasified and remaining ash discharged therefrom, and a reduction region in which a combustible fuel gas is created from combusted pyrolysis gas passed through said tar component thermal cracking region; and is a vertical shaft furnace having an insertion port, a first accumulator, a first oxidation gas supply part, a second accumulator, a gas extraction port, a second oxidation gas supply part, and an ash trap in sequence starting from a topmost part towards a bottom part,
said insertion port connects to said thermal cracking unit and feeds the tar-containing pyrolysis gas and char to said gasification unit,
said first accumulator is formed beneath said insertion port and temporarily stores flowing char downward from said insertion port,
said first oxidation gas supply part is formed beneath said first accumulator to define inside a downflow duct for the flowing char and introduces an oxidation gas into said downflow duct,
said second accumulator is formed below and connects to said downflow duct and provides a space for temporary storage of char flowing downward through said downward duct,
said gas extraction port is formed at a top portion of said second accumulator directly below said first oxidation gas supply part and extracts gas generated in said gasification unit,
said second oxidation gas supply part is structured at a lower portion of said second accumulator, guides the char downward and allows introduction of oxidation gas into said second accumulator,
said ash trap is formed directly beneath said second accumulator,
said tar component thermal cracking region is formed by a combustion reaction of the pyrolysis gas and oxidation gas supplied from said first oxidation gas supply part,
said char gasification region is formed by a combustion reaction of the char and oxidation gas supplied from said second oxidation gas supply part, and
said reduction region is formed between the tar component thermal cracking region and char gasification region to reduce the combusted pyrolysis gas by the flowing char.