2 replies to this topic

We have a horizontal shell and tube exchanger with slurry being through tube side. We used to face frequent fouling and precipitation issues in the tubes that drops heat transfer efficiency and requires chemical and/or mechanical cleaning. What is the best engineering practice for such applications? does it help to put the exchanger in vertical or inclined position? Appreciate all thoughts.

[Chris Haslego]

Look into a spiral heat exchanger. They've solved many of these problems over the years.

[Art Montemayor]

Mohammad:

Chris is giving you some solid and valued advice. You have the wrong type of exchanger applied in this service.

I love this topic. I have had so much success in the past in applying spiral exchangers in challenging services that I have frequently written on this topic in our Forums in the past. Please refer to the attached pictures I just took of something I keep on my desktop. I think the pictures literally say a thousand words.

I don't sell or sponsor Alfa Laval spiral exchangers. I have no interest in doing so. However, the fact that they cost more than the conventional TEMA shell & tube types is important to note because my experience in difficult applications (such as yours) have demonstrated that the extra capital cost is easily justified and merited when one applies the constant and hazardous expenses of applying shutdown time, maintenance labor, hazardous and dangerous chemicals, and the wear and tear of heavy and repeated physical cleanings, the obvious superior characteristics of the spiral exchanger come to the surface:

• It handles slurries without plugging. And even if an occasional large solid get through and causes a plug-up, the unit is opened 100% (on either side) and quickly (in under an hour) and simply put back into service.
• The inherent very large (and efficient) surface heat transfer coefficients obtained with spiral flow are well-known. This feature makes the unit much smaller and compact than the shell & tube.
• The relatively small foot print makes for less expensive and simpler piping and valving.

In sumary, you could eliminate your maintenance, downtime, and chemical treatment with a spiral exchanger. It is the right tool for the job at hand.

Attached Files

•  Spiral Xchanger#1.JPG   101.8KB   18 downloads
•  Spiral Xchanger#2.JPG   85.23KB   21 downloads
•  Spiral Xchanger#3.JPG   121.86KB   22 downloads
•  Spiral Xchanger#4.JPG   131.53KB   18 downloads