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|Type:||Artigo de periódico|
|Title:||Preparing and characterizing biocarbon electrodes|
|Abstract:||In this research, eucalyptus wood is used as a source of coke (charcoal) and pitch (biopitch) feedstocks for the production of graphite-like materials. The wood process starts with batch pyrolysis of Eucalyptus saligna wood samples heated up to 1000 degrees C under a heating rate of 3 degrees C min(-1). Volatiles are condensed to originate an organic tar (bio-oil), and later distilled to recover heavier fractions that are used as a binder in the electrodes manufacture. The solid charcoal is ground and compressed together with biopitch. The pre-molded green electrode has a 25-mm diameter and 120-mm length. It is read to be cured in an increasing temperature treatment. The next step is the calcination at 1000 degrees C, followed by graphitization at 2700 degrees C. The material presented a turbostratic structure, which is monitored by X-ray diffraction (XRD), and the line widths of (002) and (100) lines indicate values of L-c = 12.4 nm and L-c = 56.5 nm. The electrical resistivity of the biocarbon samples, treated at heat temperatures (HTT's) higher than 900 degrees C, presented values of 10(-4) Omega m. Compression tests indicate that Young's modulus has a maximum of 3.0 GPa at HTT of 1000 degrees C. The rupture strength also goes through a maximum of 50 MPa at similar HTT. Thermal expansion measurements indicate a linear coefficient of 6.10(-6) degrees C-1 for the samples heat-treated at 2700 degrees C. In this work, a comparison between the biocarbon electrode (BCE) and a traditional electrode from coal and petroleum derivatives is made. We found out that an ordinary electrode used to scratch furnace has comparable properties to BCE. The main purpose of this research is to prove that electrodes can be made from renewable sources and, in this way, decrease pollutant in the industrial process. (C) 2000 Elsevier Science B.V. All rights reserved.|
|Editor:||Elsevier Science Bv|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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