Perspectives: Plant InSites

Ease Measurement of Column Internal Flow

Opting for a pump instead of gravity to return liquid to a tower often makes sense

By Andrew Sloley, Contributing Editor

Last month, we looked at using a gravity-flow loop to measure liquid flow inside a column (“Get Some Inside Information[http://goo.gl/CTYvck]”). An often-attractive alternative uses a pump to return the total liquid draw taken from the column. The important engineering fundamentals of this system lie in the pump and control logic.

Read more

More from this perspective...

Title

Don’t let parallel pumps cross you up

Small differences with parallel pumps can lead to big difficulties, according to Andrew Sloley in this month's Plant InSites column.

03/28/2007

Keep others from making “classic” mistakes

A heat exchanger problem provides a textbook example of design limitations, according to Contributing Editor Andrew Sloley.

04/24/2007

Teaming two solutions can be counterproductive

Sometimes things just don’t add up as expected. Andrew Sloley discusses how sometimes two solutions aren't always better than one solution.

06/06/2007

Properly protect centrifugal pumps

Consider various factors when selecting how to guard against low flow, Andrew Sloley says in this month's Plant Insites column.

07/11/2007

Don’t look at precondensers in a vacuum

Consider the impact of the downstream vacuum ejector on precondenser performance, advises Andrew Sloley, in this month's Plant InSites column.

08/20/2007

Correct those disturbing lapses

Keeping liquid in a reflux drum still can prevent problems, says Andrew Sloley, in this month's Plant InSites column.

08/31/2007

Do some heavy thinking about light loads

Cutting steam demand can get you into hot water, advises Contributing Editor Andrew W. Sloley, contributing editor, in this month's Plant InSites column.

10/01/2007

Carefully check vendor references

Determine the differences between a cited installation and yours, Andrew Sloley, contributing editor, says in this month's Plant InSites column.

10/30/2007

Keep parallel pumps in line

Mind the curves when using different size pumps.

02/13/2008

Don’t stack the deck against yourself

Always consider future expansions before finalizing layouts

03/14/2008

Plant InSites: Cast a cold eye on columns

Subcooling can complicate and compromise tower performance

05/23/2008

Understand the cold facts about subcooling

Systems sometimes can surmount major layout errors

06/04/2008

Use water to check vessel integrity

Hydrostatic testing offers advantages but requires care

06/25/2008

Right Vacuum Control Choice Takes the Pressure Off

Choosing the proper recycle stream for regulation is crucial

08/07/2008

Plant InSites: Look Beyond the Lore

Don’t rely on recollections about how a unit had performed

10/10/2008

Full Vacuum Rating Isn't an Empty Benefit

It often can provide important but underappreciated advantages for vessels

10/16/2008

Stripper Bares All

Analysis reveals how operating practices compounded design mistakes

11/21/2008

Steam Systems: Simple Solutions Can Prompt Complex Problems

Steam systems are especially susceptible to developing difficulties

12/23/2008

Troubleshooting: Take to the Field

Troubleshooting demands getting into the plant to inspect units.

01/30/2009

Take Control Down a Level

Sometimes you can design out the need for instrumentation.

02/23/2009