Distillation cycle time

Let the apparatus cool completely. You should see a yellow to red sublimate on the walls of the glassware, or as a crust above the stibnite residue. Return the distillate to the residue, rinsing all of the sublimate from the walls. Repeat this distillation cycle two more times. The liquid from the final distillation is the Vinegar of Antimony. In this form it is still a weak solution but has excellent healing qualities of its own. Basil Valentine says it will eliminate all toxins from the body. 

The sharpness of the separation is determined by the reflux ratio. Since the reflux rate is limited by hydraulics considerations (Chapters 14 and 15), higher reflux ratios would require lowering the distillate rate, thus lengthening the distillation cycle. The separation sharpness must therefore be weighed against the time required to complete the distillation. 

Eor batch distillation size based on cycle time fill, distill, discharge bottoms, clean, for = 2, NTS = 10 reflux ratio 20 1 Op,p = 4, NTS = 6 reflux ratio 12 1 Op,p = 10, NTS = 3 reflux ratio 7.5 1 To convert TS to height of packing ... 

The distillation coil has an expansion chamber partially filled with 1-mm glass beads, a bottoms draw to remove hot acid and an overhead draw to remove vapours. The cycle time includes 1 min for sampling and 3 min for washing. 

The modern batch deodorizer has a capacity from 5 to 30 tonnes. It is still frequently constructed of mild steel, though stainless steel is preferred. It is heated by high-pressure steam or, in some cases, by Dowtherm or thermal oil, and its vaporization efficiency has been improved by the inclusion of mammoth pumps and effective head space insulation to prevent refluxing. A vapour scrubber can be installed to recover oil and fatty acids from the distillate vapour. The complete batch cycle time is between 6 and 10 h depending on the feedstock. The unit is not, however, suitable for physical refining and it is expensive to operate compared with continuous and semi-continuous plant. 

Scheduling and cycle time analysis in the context of a simulator is fuUy process-driven and the impact of process changes can be analyzed in a matter of seconds. For instance, the impact of an increase in batch size (which affects the dmration of charge, transfer, filtration, distillation, and other scale-dependent operations) on the recipe cycle time and the maximmn nmnber of batches can be seen immediately. Due to the many interacting factors involved with even a relatively simple process, simulation tools that allow users to describe their processes in detail, and to quickly perform what-if analyses, can be extremely useful. 

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