An integral characterization study on olive stones pyrolysis

P. A. DELLA ROCCA; G. I. HOROWITZ; P. R. BONELLI; M. C. CASSANELLO; A. L. CUKIERMAN

Banff

Congreso; Developments in Thermochemical Biomass Conversion Conference; 1996

Olive stones, a numerous agricultural by-product in several countries,  have been recognized as an interesting source for activated carbons production. Two steps thermal activation processes are commonly applied for activated carbons preparation, being pyrolysis of raw materials the first one  Significant variations in chemical comwsition and oore structure of the solid with pyrolysis extentoccur due to a complex network of reactions The present paper is concerned with several aspects involved in olive stones pyrolysis, focusing on the reaction study togaher with the analysis of the evolution of physical and textural modifications  Non-isothermal experimems are carried out at aheating rate of 10 K/min up to l273 K. Isothermal ones are performed at l00 K/min and nine different temPeratures within the range of olive stones decomposition On the other hand, in order to analyze chemical and textural variations of olive stones during pyrolysis, experiments in a fixed bed reactor heated by an electric furnace are carried out by pyrolyzing them at different final reaction temperatures during one hour. Proximate and elemental analvsis of the samples obtained in this wav are performed. Besides, specific surface areas are evaluated from adsorption isothermsemploying carbon dioxide at 298 K by applying the Dubinin-Radushknich eauation. As expected, samples carbon contents and surface areas increase with pyrolysis temperature Virgin stones and samples stmcture modifications are vimalized by optical and scanning electronic microscopy (SEM), respectively. volysis trends to open the structure due to volatile materials release. Increasing temperature leads to generation of new pores and to a significam pores widening. rhex trends are supponed by surface area values found in each case. A recent model,  reported in the literature, verified for pyrolysis of lignin, is applied to fit TG data. Model is found to describe satisfactorily olive stones pyrolysis. Present results contribute to improve the understanding of olivestones pyroly;is and may be of particular utility when they are employed as precursorsfor activated carbons preparation.