ET25SWG0014 - Walnut Drying Tool

Infrared drying of walnuts has demonstrated to significantly reduce drying Not Reviewed
times (by 25-35%) and energy usage. This involves moisture-based sorting and IR
pre-drying of walnuts, followed by conventional hot air drying. The scope of this
agile project comprises of literature review of this technology (Dr. Pan’s study at UC
Davis) and development of spreadsheet-based energy savings calculator. The
objective of the tool development would be to estimate energy savings and payback
period of IR process drying; based on customer specific inputs such as number and
output of burners (MMBTU/hr) , length of season, operating hours, production rate
(tons/hour) and number of conveyor lines. Average gas and electric utility rates
would be selected based on climate zone/location. The project would also compile
estimated cost info. Of natural gas catalyzed IR heater (equipment and installation)
for determining payback period.

The current process involves cleaning, washing, and conveying of walnuts to drying
nuts. Hot air at 43 degrees Celsius is used to dry walnuts from their initial moisture
content to a moisture level of 8% on wet basis. The quality of drying process affects
the product quality significantly. This highlights the importance of emerging
technology related to walnut drying to reduce the drying time and energy usage
without affecting the quality of walnuts.