Monday, June 27, 2011

A Primer on BOILER PRIMING / Carryover Problems

If you are experiencing "boiler priming", sometimes called "carry over", resulting in boiler plant shut-downs and/or water hammer, there is good news.  

There are a number of solutions that can readily mitigate this.  

Contact ERB and Associates, Inc.
Richard Bockwinkel by phone: 913.579.7688 or eMail:

The PRIMER...In a boiler steam bubbles are continually bursting at the steam water interface and ejecting boiler water drops into the steam space.
As the rate of steaming increases a point is reached where the steam bubbles are arriving at the surface faster than they are being removed, they accumulate as foam.

Steam released from the bursting bubbles move towards the steam outlet carrying with it smaller water droplets and taking with it any foam.

The steam also drags the surface of the boiler water towards the steam outlet so that the water level at that point can be higher than elsewhere, depending on the positions of the level controls this may cause the feed pumps to deliver water and thus raising the water level further.

As the water level is raised the volume of the steam space is decreased, the speed of the steam across the surface is increased drawing foam and water droplets towards the steam outlet. A sudden increase in steam demand can cause a slug of boiler water to enter the steam outlet.  This is known as priming.  Operation of the boiler below its design pressure will also produce a similar effect.

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