Condenser and Pressure Control—Single-Phase Product

2 Condenser and Pressure Control—Single-Phase Product 

Column pressure is perhaps the most important control variable in a distillation column. Pressure affects condensation, vaporization, temperatures, compositions, volatilities, and almost any process that occurs in the column. It has been the author s experience that a column will not achieve stable operation unless steady pressure can be sustained. Note that this does not preclude pressure variations, as long as these are performed slowly and steadily. 

As previously described (Chap. 16), column pressure control is usually integrated with the condensation system. Pressure and condensation controls therefore need to be considered simultaneously. An ex- 

Some general guidelines for pressure and condensation control (77) are 

Streams should enter the reflux drum at a velocity low enough to prevent disturbance to the liquid surface. 

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