Flow-control-free intermittent fine distillation method and apparatus

Abstract

The present invention relates to an intermittent rectification method having no need of controlling flow rate and its equipment. It is characterized by that the upper portion of the rectification tower adopts external partial condensing rectifying section to provide back flow, and is utilizes the control of external cooling medium state to control temperature of tower top. As compared with existent technique said invented product purity is higher, its quality is more stable, its operation and control are more convenient, its transition fraction can reduce by above 20%, and its energy consumption can reduce by above 20%. It is specially applicable to separation of anaphylactic material, reduced pressure intermittent rectification and small test intermittent rectification.

Description

technical field [0001] The invention relates to a rectification method and equipment in chemical unit operation, in particular to a batch rectification method and equipment without flow control. Background technique [0002] Batch distillation is a separation operation that divides a batch of materials into multiple fractions through multi-stage partial vaporization and partial condensation. Because it can adapt to different materials and separation requirements in the same set of equipment, it has strong flexibility and low investment. And other advantages, it is widely used in small-scale fine chemical and pharmaceutical industries. At present, there are two operation methods for batch rectification, one is the operation method of constant distillate composition, which maintains the composition of distillate by continuously increasing the reflux ratio, which is the main operation method for batch distillation to obtain products; the other is The operation method of consta...

AI Technical Summary

Problems solved by technology

In the operation process of constant distillate composition, since the reflux ratio is continuously changing, the operation control requirements for the output volume or reflux flow are relatively high, especially it is difficult to obtain high-quality products; in the process of constant reflux ratio operation In the process, due to the large liquid holding capacity of the reflux operation equipment at the top of the rectification tower, there are too many transition fractions, which increases the difficulty of separation.

The method to improve these deficiencies is to increase the volume of the tower kettle, increase the processing capacity of each batch, slow down the change of the reflux ratio and make it easy to control and reduce the influence of the liquid holdup on the top of the tower on the increase of the transition fraction. However, increasing the batch processing capacity not only increases investment, but also Increased heat loss is extremely unfavorable to vacuum rectification that requires a low liquid level in the tower or heat-sensitive material rectification that does not take too long to process each batch.

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