Physical durability and stability of olive cake briquettes

Abstract

Al-Widyan, M.I., Al-Jalil, H.F., Abu-Zreig, M.M. and Abu-Hamdeh, N.H. 2002. Physical durability and stability of olive cake briquettes. Canadian Biosystems Engineering/Le genie des biosystemes au Canada 44: 3.41-3.45. Olive pressing in Jordan generates large amounts of olive cake that impose disposal and environmental problems. The full benefits of densifying olive cake for energy or other uses are realized only if the physical quality of densified units is secured. Thus, this work involved evaluating the physical quality of olive cake briquettes made by compressing loose olive cake in a closed-end cylindrical die using a hydraulic press under different levels of stress, moisture content, and dwell time. A data acquisition system was used to collect load and deformation data from a load cell and a linear variable differential transformer. It was found that only moisture content and stress had significant effects on briquette durability and stability. Linear models to predict briquette durability and relaxed density as a function of stress and moisture content were developed. Material moisture content had a greater impact on quality, probably due to favorable effects of biological activity. The significance of stress on quality vanished at moisture content greater than 30% (w.b.). The stress and moisture content levels of 35 MPa and 30 to 35% with dwell time of 5 s or less were considered optimal, resulting in highly durable olive cake briquettes with relaxed density of about 1100 to 1300 kg/m, which is more than twice the density of the loose material.