Studies On Pyruvic Processes Of Extraction, Purifiction And Concentraion

The dissertation mainly focuses on the pyruvic acid processes of extraction, purifiction and concentration from the pyruvate fermentation broth.The method of determination of pyruvate's content was studied by ultraviolet absorption spectrophotometry. At pH11.0 and 320nm, pyruvate could achieved high absorption than other organic acids and coexistent components. The concentration of pyruvate from 0.2 to 2.8g/L was just in accordance with Beer's law. This method is simple and has high selectivity for the determination of pyruvate in the fermentation broth and its product.The ion-exchange method was studied. 732 cationic resin was chosen to decolour the fermentation broth besides to play the role of cation exchange. So the process was reduced and the recovery was enhanced for the pyruvic acid.D315 weakly-basic anion resin was selected for its superior performance to purify pyruvic acid. In the single fixed-bed ion-exchange operation, the recovery percent of pyruvic acid was 96.60%.An idea of elution in circles was suggested. By this method, pyruvic acid and hydrochloric acid could be separated enough without to add the height of anion fixed-bed. The concentration of pyruvic acid could achieve 400g/L which reflects the advantage of ion-exchange operation in concentration. After eluting 30 anion fixed-beds, the recovery percent of pure pyruvic acid obtained 95.67%.The molecule distillation also was studied. To the mass percent of pyruvic acid from 15 to 30, such conditions is optimal: 10Torr in pressure, 70℃ in temperature, the 120mL/h of flow rate, the 30% of rotate rate to rotor. After two steps of molecule distillation, the recovery percent of pure pyruvic acid was above 89.99% and its content achieved 99.01%.By above research, the total recovery of pyruvic acid was above 81.22%, purity achieved 99.01% and every items satisfied the standard.