Characterization and analysis of the drying real process in an industrial olive-oil mill waste rotary dryer: A case of study in Andalusia

Abstract Since 1991, the main by-product obtained in the olive oil extraction process is the two-phase olive-oil mill waste. To remove it, the main treatment is the drying in rotary dryers placed on secondary extraction factories. Andalusia has 39 of the 63 industrial plants in Spain. Drying of this by-product is vital for sustainable development of olive sector which eliminates a serious environmental problem, obtains the olive pomace oil and generates a biofuel called dry de-oiled pomace. This article develops a methodology to study and analyze the drying behavior in an industrial olive-oil mill waste rotary dryer. The results are compared to design parameters related to the drying of three-phase olive-oil mill waste or olive pomace in past years and for which rotary dryers were designed. After evaluating the results, the main problems are identified and several solutions and future proposals are commented.