title: Improved product energy intensity benchmarking metrics for thermally concentrated food products.
abstract: Product energy intensity (PEI) metrics allow industry and policymakers to quantify manufacturing energy requirements on a product-output basis. However, complexities can arise for benchmarking of thermally concentrated products, particularly in the food processing industry, due to differences in outlet composition, feed material composition, and processing technology. This study analyzes tomato paste as a typical, high-volume concentrated product using a thermodynamics-based model. Results show that PEI for tomato pastes and purees varies from 1200 to 9700 kJ/kg over the range of 8%-40% outlet solids concentration for a 3-effect evaporator, and 980-7000 kJ/kg for a 5-effect evaporator. Further, the PEI for producing paste at 31% outlet solids concentration in a 3-effect evaporator varies from 13,000 kJ/kg at 3% feed solids concentration to 5900 kJ/kg at 6%; for a 5-effect evaporator, the variation is from 9200 kJ/kg at 3%, to 4300 kJ/kg at 6%. Methods to compare the PEI of different product concentrations on a standard basis are evaluated. This paper also presents methods to develop PEI benchmark values for multiple plants. These results focus on the case of a tomato paste processing facility, but can be extended to other products and industries that utilize thermal concentration.
authors.affiliation: Northwestern University , Department of Chemical and Biological Engineering, 2145 Sheridan Rd, RM E136, Evanston, Illinois 60208, United States.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Walker
authors.forename: Craig S
authors.initials: CS
authors.lastname: Arnold
authors.forename: David J
authors.initials: DJ
authors.lastname: Lettieri
authors.forename: Margot J
authors.initials: MJ
authors.lastname: Hutchins
authors.forename: Eric
authors.initials: E
authors.lastname: Masanet
mesh_terms: D000465:Algorithms; D005511:Food Handling / Q000592:standards*; D006358:Hot Temperature; D018551:Solanum lycopersicum; D013816:Thermodynamics