Saving energy upon water removal in drying by making the α-polymorph of L-glutamic acid

Drying is an energy-intensive operation for the separation of a desired solid product, when it consumes 12-20% of the entire energy used in manufacturing processes. Without changing the existing drying method or equipment, making alpha-form of L-glutamic acid (alpha-Glu) by reactive crystallization can reduce the energy consumption for drying in terms of much less initial moisture content of 23.32% and time of 4.67 h , as compared to 48.52% and 6 h for its beta-form in the present study. Upon drying, alpha-Glu shows less affinity for hydrogen bonding with water, as ammonia cations on alpha-carbon of L-Glu are projected on the alpha-Glu's surface. On the contrary, more hydrophilic carboxylate anions on alpha-carbon are exposed on the surface of beta-Glu, which tends to form agglomerates during reactive crystallization, causing stronger interaction with water. As a consequence, 35% of energy utilization in drying can be saved by making alpha-Glu.