Development of an innovative rotating spiral heat exchanger with integrated microwave module for the olive oil industry

Abstract A new prototype of an integrated tube-in-tube heat exchanger with rotating spiral coil and microwave module is proposed. The prototype was installed in an industrial olive oil extraction plant and tested to determine how much it improved overall extraction performance of the plant and olive oil quality. Nominal mass flow rate showed that the prototype was perfectly integrated in the plant. Thanks to the transport action of the rotating spiral coil, the prototype did not affect the feed pressure of the olive paste from the crusher to the malaxer. Using the heat exchanger, malaxing time was reduced by 50% without decreasing oil extraction. The microwave module increased oil extractability. The new prototype applied to mechanical extraction of virgin olive oil enhanced the quantitative and qualitative composition of hydrophilic phenols without altering legal quality parameters or significantly modifying the volatile fraction.