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Measurement of viscosity of suspensions during wheat bran processing
Koukal, Jan ; Slavíková, Zuzana (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis deals with the assessment of the viscosity evolution of wheat bran suspension during alkaline hydrolysis. Wheat bran is a widely produced low-cost by-product of the milling industry. Due to its composition, bran is a suitable substrate for biorefining and involvement in the circular economy. However, during processing, viscosity development occurs, which greatly affects the energy requirements for processing. The temporal evolution of viscosity during alkaline hydrolysis was determined using a rotational rheometer at constant shear rate. Viscosity was assessed as a function of NaOH concentration, temperature and bran ration. Furthermore, the evolution of viscosity was measured during alkaline extraction of proteins. The highest viscosity was measured in a 0.2 M NaOH system at 30 °C with a bran to hydroxide ratio of 1:10. Its value was 0.991 ± 0.010 Pa.s. Based on the theoretical part and the data obtained from rheological measurements, the design of a stirred reactor for wheat bran processing on an industrial scale was carried out. It is a vertical cylindrical vessel with a total volume of 10 m3. The vessel is equipped with three Chemineer HE-3 hydrofoil impellers mounted on a vertical shaft. The power input of the agitator was calculated at 2.8 kW and compared to a conventional 4-blade, 45-degree pitched blade turbine, the chosen design was four times more efficient.
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Measurement of viscosity of suspensions during wheat bran processing
Koukal, Jan ; Slavíková, Zuzana (referee) ; Pořízka, Jaromír (advisor)
This bachelor thesis deals with the assessment of the viscosity evolution of wheat bran suspension during alkaline hydrolysis. Wheat bran is a widely produced low-cost by-product of the milling industry. Due to its composition, bran is a suitable substrate for biorefining and involvement in the circular economy. However, during processing, viscosity development occurs, which greatly affects the energy requirements for processing. The temporal evolution of viscosity during alkaline hydrolysis was determined using a rotational rheometer at constant shear rate. Viscosity was assessed as a function of NaOH concentration, temperature and bran ration. Furthermore, the evolution of viscosity was measured during alkaline extraction of proteins. The highest viscosity was measured in a 0.2 M NaOH system at 30 °C with a bran to hydroxide ratio of 1:10. Its value was 0.991 ± 0.010 Pa.s. Based on the theoretical part and the data obtained from rheological measurements, the design of a stirred reactor for wheat bran processing on an industrial scale was carried out. It is a vertical cylindrical vessel with a total volume of 10 m3. The vessel is equipped with three Chemineer HE-3 hydrofoil impellers mounted on a vertical shaft. The power input of the agitator was calculated at 2.8 kW and compared to a conventional 4-blade, 45-degree pitched blade turbine, the chosen design was four times more efficient.
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