Pyrolysis of Olive Mill Waste with On-line and Ex-post Analysis

Abstract

Olive mill wastes constitute a serious environmental problem in the Mediterranean region due to the unique features associated with this type of agricultural waste. Therefore, it is not surprising that research efforts have been directed towards developing efficient treatment technologies including various physical–chemical processes. In this paper we present a thermo-chemical degradation method (pyrolysis) to produce biochar. The large part of work is devoted to understand the pyrolysis processes using on-line analysis of thermal parameters and chemical composition. The originality of our work resides in the on-line analysis in the form of temperature measurements during individual pyrolysis cycles as well as the whole pyrolysis process, accompanied with on-line measurements of component concentrations during the whole pyrolysis process. On-line and ex-post analysis of gas phase composition provides important information about environmental impacts of the pyrolyzing process. The concentration profiles of CO, CO2, CH4, H2 and NOX were measured at four locations within the pilot system with a high sampling frequency (every 8 s) during whole pyrolysis process. In terms of the general aspects and possible future application of pyrolysis and its products we propose a novel method capable to reduce carbon dioxide concentrations in pyrolysis gas. The average CO2 removal efficiency during the whole pyrolysis process was as high as 65%. The final product is solid proteinoid. The pyrolysis process decrease the amont of waste to 10% of input amount of material. The carbon char produced in the system may find several applications especially in the agriculture.