TIP OF THE DAY
If a product quality problem cannot be corrected easily by increasing the draw rate of heads or other congeners, the best action is to slow the rectification operation and reduce throughput until the problem is corrected. In extreme cases, the rectifier may be put on total reflux . This is a situation where the feed rate to the extractive distillation column is reduced to the point where there is just enough volume to meet the requirements of the congener draws, and none or almost no excess for the product draw. Under these conditions, quality problems can be corrected rapidly and the extractive distillation column feed rate can then be gradually increased to normal maximum rate.