| dc.description.abstract | Energy-saving is an important global issue. Drying, especially, occupies 12% of the energy consumption in the entire process in the industry. Therefore, improving the drying behavior could greatly reduce energy consumption. However, information on polymorphs related to drying behavior is missing. The purpose of this study is to investigate the effects of polymorphs of L-glutamic acid crystals on drying behavior, and to design a process to prepare pure α form L-glutamic acid crystals with uniform particle size. The first part of this study is the drying experiments of polymorphism. The crystals of α-L-glutamic acid and β-L-glutamic acid have been prepared by reaction crystallization in this study, respectively. All these reaction products were used for 40°C drying experiments, where weight loss was recorded as a function of time. It could be found that α-L-glutamic acid crystals exhibited a less total drying time. β-L-glutamic acid crystals were easier to retain moisture in their filter cake due to their crystal molecular surface structure. Consequently, α-L-glutamic acid crystals displayed better energy-saving performance in the drying process, reducing α-L-Glu crystals could save 35% of the energy consumption used in drying compared to the produced β-L-Glu crystals. The second part of this study is process design. This study uses the Taguchi Method to look for the optimal parameters to produce α-L-Glu crystals with desired particle size and particle size distribution. The selected parameters include: (1) addition rate of 1M sulfuric acid(aq) (2) reaction temperature, (3) stirring rate, and (4) concentration of L-phenylalanine (L-Phe). According to the response table and figure, the appropriate combination should be selected to produce the desired particle size. Among the four parameters, reaction temperature has the greatest impact on the stability of the system. In addition, the optimal combination that could give the narrowest particle size distribution is 1M H2SO4(aq) addition rate of 1 mL/s, the concentration of L-Phe of 5.20×10-2 M, reaction temperature of 35℃, and stirring rate of 500 rpm. That information will help to further scale up the process. | en_US |