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Design and Evaluation of a Laboratory-Scale System for Investigation of Fouling during Thermal Processing Operation

Huang, Yunqi
http://rave.ohiolink.edu/etdc/view?acc_num=osu1494245242027853

Abstract Details

2017, Master of Science, Ohio State University, Food, Agricultural and Biological Engineering.
In the food and beverage industry, fouling of food contact surface during thermal process has direct impact on performance and efficiency of operations. Relationship between fouling rates under commercial-scale operations and laboratory-scale experiments requires careful consideration. The objectives of this investigation were to develop and evaluate a laboratory-scale system to mimic a commercial-scale processing system, and to propose methods to quantify the rate of fouling on heat exchanger surface. During design and development, two experimental components were identified; stainless-steel coupons for direct measure of fouling residues and a holder to expose multiple coupons during the experimental thermal conditions. During experimental measurements, reconstituted Non Fat Dry Milk (NFDM) solutions were used. Fourteen liters of 20% w/w NFDM solutions were pre-heated and held in a stainless-steel vessel. An immersion heater was installed at the bottom of the vessel to increase and maintain the temperature of the NFDM solutions. A mechanical agitator was used to establish a range of shear rates over the surfaces. Flexible polymer Kapton heaters were attached to the back of each coupon to control the coupon surface temperature. Thermocouple sensors were used to monitor coupon surfaces temperatures during all experiments. In addition, a Computational Fluid Dynamic (CFD) simulation code was created to estimate the wall shear rates on all surfaces that were exposed to the fouling material. The results from the investigation confirmed that the system could be used to collect fouling data as a function of primary commercial operation parameters. The system was used to collect experimental data over a range of temperatures and times. Experiments were conducted at 65°C, 75°C and 85°C and coupons were removed at 30 minutes intervals for a total duration of 120 minutes. Two methods for measurements of fouling (thermal resistance and protein quantification) were investigated. In addition, the wall shear rate on the coupon surfaces was estimated for various rotation speeds based on the CFD simulation model. The results of the investigation demonstrated that fouling resistance and the amounts of protein residue on the coupon surfaces increased linearly with time at each process temperature. The rate of fouling increased with product temperature. A linear model described the rate of fouling magnitude that measured through fouling thermal resistance ranged from 3.6*10e-5 (°C m2 kW-1min-1) at 65 °C to 1.06*10e-3 (°C m2 kW-1min-1) at 85 °C. The activation energy for the fouling process based on fouling resistance and protein deposits were170.91 kJ mol-1 and 37.2 kJ mol-1. A linear relationship between thermal resistance and protein fouling over three process temperatures was established. This relationship provides the basis for on-line fouling resistance detection to estimate the amount of fouling on a surface during a thermal process. Finally, the results from this investigation have demonstrated a method for more thorough investigation of fouling mechanisms and the factors influencing the rate of fouling during thermal processes.
Dennis Heldman, R. (Advisor)
Sudhir Sastry (Committee Member)
V. Blasumramaniam, M. (Committee Member)
99 p.
Agricultural Engineering
NFDM fouling, protein denaturation, fouling resistance, protein quantification, shear

Recommended Citations

Citations

  • Huang, Y. (2017). Design and Evaluation of a Laboratory-Scale System for Investigation of Fouling during Thermal Processing Operation [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1494245242027853

    APA Style (7th edition)

  • Huang, Yunqi. Design and Evaluation of a Laboratory-Scale System for Investigation of Fouling during Thermal Processing Operation . 2017. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1494245242027853.

    MLA Style (8th edition)

  • Huang, Yunqi. "Design and Evaluation of a Laboratory-Scale System for Investigation of Fouling during Thermal Processing Operation ." Master's thesis, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1494245242027853

    Chicago Manual of Style (17th edition)

osu1494245242027853
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This open access ETD is published by The Ohio State University and OhioLINK.