Design and performance evaluation of an ohmic heating unit for thermal processing of highly viscous liquids

• DOI: 10.1016/j.cherd.2008.02.005
• Publication Date: 2008-09-22T13:38:39Z
• Authors: S. Ghnimi; N. Flach-Malaspina; M. Dresch; G. Delaplace; J.F. Maingonnat
• Keywords: 04 agricultural and veterinary sciences; 7. Clean energy; 620; Radar sensor; 0404 agricultural biotechnology; ohmic heating; [SDV.IDA]Life Sciences [q-bio]/Food engineering; fluid jet; fluid jet; Radar sensor; Thermal treatment; Thermal treatment; [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering; radar sensor; thermal treatment; [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition

The overall objective of this study is to design, build and test a prototype automated ohmic heating cell by using a fluid jet to serve as a basis for modification and scale-up for industrial use. The new technology consists of applying an alternative electrical current to a falling jet between two electrodes. The length of the jet is the primary critical process factor in ohmic heating using a fluid jet. A radar level sensor was validated at different operating conditions. Two air valves, that depressurize or pressurize the ohmic cell, ensure the control of the jet length for precision and reliability. The thermal performances and the technical feasibility of this innovated automated ohmic heater were approved. Tests with carboxymethylcellulose (CMC) solutions (2%, w/w) demonstrated that this technology can be efficient for thermal processing of highly viscous liquids.