CFD Analysis of a Tubular Heat Exchanger for the Conditioning of Olive Paste

Claudio Perone,Pasquale Catalano,Roberto Romaniello,Antonia Tamborrino,Alessandro Leone

doi:10.3390/app11041858

Abstract

The use of a heat exchanger for the conditioning of the olive paste could enhance the olive oil extraction process. Particularly, paste pre-heating could reduce the malaxation time and, most of all, improve the temperature control during this process (e.g., 27 °C). In this study, a three-dimensional computational fluid dynamics (CFD) analysis of a tubular heat exchanger was carried out to better understand the influence of the inlet conditions of the olive paste on thermal and hydrodynamic behavior within it. CFD analysis was performed with SOLIDWORKS Flow Simulation (ver.2016). The heat exchanger consists of a tube-in-tube module, in which the inner tube was fed with the olive paste, while the jacket was filled of hot water. The main aim was that to predict the heat transfer and pressure drop in paste side of the exchanger. Multiple analyses by varying the mass flow rate and inlet temperature of the paste were carried out, and temperature and pressure drop were estimated. The numerical model has proved very useful in identifying the main factors affecting the optimization of the heat exchanger in order to improve the extraction process of the olive paste.

Highlights

Heat exchangers are thermodynamic equipment widely used in food processing industries mainly for different type of engineering applications such as heating and cooling as reported in [1,2,3].Just as in many food industries in the industry of extracting virgin oil from olives, there is the need to thermally adapt the olive pastes during the process
The mass flow rate was varied from 1000 up to 3000 kg/h with a step of 500 kg/h, and the inlet temperature was set to 7, 12, 15, 17 and 20 ◦ C for each mass flow rate. This means that 25 scenarios were obtained, since the main aim of this work was to predict the behavior of the heat exchanger in the olive oil extraction process, where it is not unusual to have a high variability of the inlet conditions of the product
The water, which flows with a mass flow rate of about 1.8 kg/s, has an inlet temperature that is kept to 40 ◦ C in each scenario

Summary

Introduction

Heat exchangers are thermodynamic equipment widely used in food processing industries mainly for different type of engineering applications such as heating and cooling as reported in [1,2,3].Just as in many food industries in the industry of extracting virgin oil from olives, there is the need to thermally adapt the olive pastes during the process. The olive paste traditionally is loaded in the malaxer machine and heated to 24–27 ◦ C for up to 30–45 min. The previously reported malaxation time/temperature ranges are recognized by the academic community as optimal to ensure high olive oil quality at the end of the process. In [5], a temperature of 25 ◦ C and times ranging between 30 and 45 min were the optimal operative conditions for the malaxation to optimize sensory characteristics, secoiridoid compounds and the volatile composition of oils extracted from olive fruits from Coratna and Frantoio cultivars. In [6], the optimal malaxation time/temperature was identified in 30 min at 26 ◦ C to preserve the volatile and phenolic composition of the olive oil from olives of Moraiolo cultivar

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