다음 내용은 Distillation Operation (Henry Kister)에 나오는 내용입니다.

The hot vapor bypass arrangement, however, has several disadvantages, and its operation can be troublesome. Because of the liquid leg between the condenser and the drum, this technique can suffer from interaction between the drum and the condenser liquid level and from U-tube oscillations. To minimize the interaction, the pressure controller should be tuned much tighter than the drum level controller. There is an inverse response problem ; when pressure rises, it closes the bypass valve, which initially causes a further increase in pressure until the condenser level begins to fall. There is a reliance on subcooling in order to enable upward liquid movement and condensation of hot vapor against the drum surface. Operation may be troublesome if the drum liquid surface is agitated; a case of instability due to inadvertent agitation has been reported. Since the success of this technique is contingent on maintaining a small vapor pressure difference, the reflux drum vapor space needs to be insulated to minimize interference from rainstorms. The above instabilities appear to be more pronounced with narrow boiling-range mixtures, and at high pressures, where small temperature changes have a large effect on the split of overhead flow between the condenser and bypass.

 

위 내용 중에서

at high pressures, where small temperature changes have a large effect on the split of overhead flow between the condenser and bypass.

부분이 잘 이해가 안 가네요...

 

왜 고압에서 운전되는 경우에 약간의 온도 차이가 condenser / bypass의 split에 영향이 크다고 할까요?

 

감사합니다.