Effect of pyrolysis temperature on composition, surface properties

P. R. BONELLI; P. A. DELLA ROCCA; E. G. CERRELLA; A. L. CUKIERMAN

BIORESOURCE TECHNOLOGY

ELSEVIER SCIENCE LTD.

Lugar: OXFORD, UK; Año: 2001 vol. 76 p. 15 - 22

0960-8524

Changes in chemical and surface characteristics of Brazil Nut shells (Bertholletia excelsa) due to pyrolysis at di?erent temperatures (350°C, 600°C, 850°C) were examined. For this purpose, proximate and ultimate analyses, physical adsorption measurements of N2 ()196°C) and CO2 (25°C) as well as samples visualisation by scanning electronic microscopy (SEM) were performed. Appreciable di?erences in the residue characteristics, depending markedly on the pyrolysis temperature, were observed. Release of volatile matter led to the development of pores of di?erent sizes. Progressive increases in micropore development with increasing pyrolysis temperature took place, whereas a maximum development of larger pores occurred at 600°C. Furthermore, kinetics measurements of Brazil Nut shells pyrolysis from ambient temperature up to 900°C were performed by non-isothermal thermogravimetric analysis. A model taking into account the signiÆcant changes in the residue during pyrolysis, through an increase in the activation energy with temperature and solid conversion, were found to properly Æt the kinetics data over the wide range of degradation investigated.