Rethink Distillation Column Pressure Measurement Inadequate sensor systems can undermine effortso optimize tower performance

摘要

PROCESS REQUIREMENTS dictate the desired pressure profile within a distillation column.Not maintaining the correct pressure at all points can lead to energy waste,inefficient operation that can cause product loss and quality problems and,in some cases,even safety issues.That's why pressure measurement is one of the most critical parameters for control of distillation processes-and why a column typically has multiple,and sometimes redundant,sensors to measure pressure in various zones(Figure 1).To maintain the desired pressure profile,the pressure instruments must work safely and reliably.This requires proper selection,calibration and maintenance.So,in this article,we'll discuss issues found when measuring pressure in distillation columns and review options,selection criteria and safety.First,let's set the stage by providing some background about common challenges.The output from a pressure sensor in a column normally goes to a ground-level pressure transmitter via an impulse line or a remote diaphragm seal with capillary tube.This impulse line or capillary tube may run a long distance-say,from the top of a 100-ft tower to ground level-to get to the transmitter.