Design and control of energy efficient drying processes with specific reference to foods

Technical Report · Fri Jul 15 04:00:00 EDT 1988

OSTI ID:5968287

Franzen, K; Kim, M; Liang, H; Murakami, E; Narsimhan, G; Okos, M; Singh, R; Waananen, K; Xiong, X

This report contains a detailed summary of all work performed to date. Task 10 involves a comprehensive review of drying theory. Proposed mass transfer mechanisms include liquid and vapor diffusion, capillary flow, surface diffusion, hydrodynamic flow, and evaporation/condensation processes. Pasta was chosen as a model system in this project since it is macroscopically homogenous and can be made under controlled conditions. Task 11 involves experimental drying studies. A high pressure drying apparatus is available for studies related to the revision of the fundamental drying model. The dryer will require two major modifications for the planned tests: installation of a pressure control valve and recirculation of exhaust gas. A tray dryer was used to measure the shrinkage coefficient of nonfat milk, and will be used for further tests on nonfat milk, as well as whey and tomato puree. A method of economic analysis regarding use of mechanical vapor recompression is presented. Task 12 involves food quality studies. A model of nonenzymatic browning (NEB) was developed based on NEB in skim milk samples containing 3.5--50% moisture, exposed to temperatures of 35--130{degrees}C. The browning rate was zero order after a lag period, and the temperature dependence fit an Arrhenius relation. The critical moisture occurs between 4% and 11% moisture. Task 13 addresses recommendations and strategies for dryer design and control. Moisture sensors were reviewed with specific reference to their on-line applicability. The IR sensor was found to be the most promising. Task 14 examined moisture mobility and interaction in foods. The BET adsorption method using nitrogen gas was applied to pasta, skim milk and egg albumin systems. The data obtained do not show good reproducibility, possibly due to an inadequate sample size. The possibility of using water vapor adsorption will be studied in future experiments. 210 refs., 30 figs., 22 tabs. (MHB)

• Research Organization: Purdue Univ., Lafayette, IN (USA)
• Sponsoring Organization: DOE; USDOE, Washington, DC (USA)
• DOE Contract Number: FG07-85ID12608
• OSTI ID: 5968287
• Report Number(s): DOE/ID/12608-T8; ON: DE91010698
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320300* -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes
BIOLOGICAL MATERIALS
BODY FLUIDS
DOCUMENT TYPES
DRYERS
DRYING
ENERGY CONSERVATION
ENERGY CONSUMPTION
FOOD
FOOD INDUSTRY
FOOD PROCESSING
INDUSTRY
ISOTHERMS
KINETICS
MATERIALS
MATHEMATICAL MODELS
MILK
MOISTURE
PROCESSING
PROGRESS REPORT
REACTION KINETICS
SHRINKAGE
TESTING
VALIDATION