Holding Time After Seeding

Since the above mentioned experimental evidences suggest primarily that the major causes of the purity drop may come from the seed crystals added to the racemic solutions, some additional experiments were conducted to examine the effects of the quality of seed crystals (Takiyama,H. et al, TUAT, unpublished data). First, the rate of crystallization, i.e. the cooling rate of the solution, and the holding time at the final temperature after the crystallization were experimentally examined. In another series of experiments in order to eliminate any possible undesired enantiomer particles from the seed crystals, seeds are recrystallized for a number of times. 

Analytical Control of Tomato Juice Processing, hi Table I characteristic chemical changes during tomato juice processing are shown. The raw material is subjected to a HB process. After a certain holding time at elevated temperatures the product is sieved in order to remove seeds and skins and pasteurized after addition of sodium chloride. 

Start-up methods. In this study, methods of start-up of a continuous cooling crystallizer are considered. Although several start-up methods are possible two typical ones as shown in Figure 2 were chosen. This description is based on the SFC (Sequential Function Chart). The SFC is conq)Osed of step and transition . Step , which is denoted with a box, shows the state of apparatus. Transition with a bold line indicates a condition that makes a move of the step . The items on the side of step are actual operations. The feed solution was charged to the crystallizer from the feed line. The feed was stopped when the liquid level arrived at the set up value, i.e. the hold up was fulfilled, l en, the solution was cooled to the operating temperature. Seed crystals were added when the solution temperature became constant at the set up value. After that, the continuous feeding and discharge were started. In this study, the experimental duration was more than 10 residence times in order to ensure the attainment of steady state. This method of start-up is defined as SU Method 1. 

---