Fouling Factors for Heat Exchanger Design

In this post I’ll list a few resources to find fouling factors for your heat exchanger designs. But first, let’s take a step back and review the definition and purpose of fouling factors in heat exchanger design.

And I thought they smelled bad...on the outside!

And I thought they smelled bad...on the outside!

Recall that in the heat exchanger sizing equation Q = U * A * LTMD, the “U” factor was a representation of all the resistances of heat exchange between the two sides. “U” was influenced by the types of fluids in the exchanger and also to a lesser degree by the material of construction of the heat exchanger. The fouling factor helps us add some additional detail, by representing the extra resistances that appear on the inside and outside of tubes after an exchanger has been operating awhile: the caked on products of fouling. There are different types of fouling, from crystalline scale to literal pieces of gunk. Fouling introduces a wrinkle into our simple equation, because now the resistance to heat exchange varies over time. But we still have to pick one exchanger design and one “A” value for the entire cycle of operation.

A properly chosen fouling factor will inform the detailed design of heat exchangers by vendors and/or software. As always, the best values to use are real-world values based on experience or tests in your own plant. Nevertheless, it’s helpful to have literature values for a starting point.

Some Literature Sources for Fouling Factors

Note that some of these links are PDF files: Continue reading

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Cost Estimation Titles in the Store

After a little downtime we are back! I have added a new category, Cost Estimation, to our store of suggested books. The collection of books by John Page, also called "Page and Nation" by some, are a great way to get manhour requirements for installing piping, HVAC systems, cable trays, and other items.

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“Learning” Spanish in 10 seconds

With the growing opportunities in Latin America, I've found myself having to deal with the occasional document in Spanish, despite never having taken so much as a high school class in Español. (I ended up with another language instead.) In some cases I've had to sift through getting everything in Spanish: the process description, P&IDs, you name it. Of course "you'll need to start learning the process before we've hired the translator." How to cope with a language you've never studied?

  1. Get electronic versions of the original documents. Get everything you can in text you can copy and paste. The less familiar you are with the characters of the language, the less able you are to type the words yourself, the more important this step is
  2. Piece by piece, run small parts of the process description and other text-heavy documents through the best translator I can find
  3. Research key words, tricky terms and language rules on a case-by-case basis it comes up.
  4. If at all possible, find someone who speaks the language (or even a related language) who can help you puzzle over the few remaining intractable issues. Or beg your boss to let you hire a translator for a few choice passages.
  5. Using your new understanding of the words and process, make sense of the P&IDs and other drawing

Here are some tools and tricks for steps 2 and 3: Continue reading

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Engineering & Business Magazine Reviews

I get a lot of work-related magazines across my desk, and definitely have my preferences in what I find useful as a process engineer & consultant. I thought I would share my narrow, heavily biased opinions, because maybe it will help some of you make the right choices for yourself.

My magazine goals

I usually read work magazines hoping to get one of three things, in this order:

  1. A new technique, ability, or resource I can feasibly call upon to do my job better or increase the range of things I can do.
  2. A relevant or inspiring story that has some value mentally preparing me for issues ahead
  3. Entertainment

Industry news, trends in chemical prices, information about stock prices and legal issues, and overview case studies tend to be less useful to me. Remember that at the moment I'm a chemical engineering consultant; your needs as a reader will vary a bit from mine.

I've also learned that trying to force yourself to read a random article you totally don't understand, in the hopes of "remembering it later," is usually a fool's errand. Better to track down such information later if and when you ever need it. Instead, you want to find articles that are on the edge of what you do know: you're pushing yourself to learn but you can understand what's going on.

With that said, let's crack open some magazines and take a look!


Chemical Engineering Magazine

Requires subscription (but see the end of this post...)

This magazine is quite tailored to my needs, and if I had to choose just one magazine for work I guess Chemical Engineering would win. I find an average of a bit less than one article worth saving per issue – sometimes nothing, but sometimes two or even three go in “the vault.” That's a very good rate of stories that I'm glad to have come across.

They also have reasonable and well-balanced editorials from multiple perspectives, which seems to be rare in an industry magazine. Most magazines cheerlead their audience like an official school newspaper but Chemical Engineering has a good range of perspectives.


Hydrocarbon Processing

Requires subscription (but see the end of this post...)

This is one of my favourites as well. They cover the lifecycle of hydrocarbons and discuss more sides than just chemical engineering. This is actually a bit of a problem for me, because the hit ratio of useful articles is a bit less than CE magazine. Some topics are totally removed from my responsibility. But I have a nice folder of great finds from HP as well, especially on relief valve analysis.

They also have a big focus on reliability and good maintenance practices. If you’re into that kind of thing Hydrocarbon Processing is the best source in this list. Continue reading

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Posted in Business / Finance, Chemical Engineering General, General Engineering Topics, Nuclear Industry, Oil, Natural Gas, Coal | Tagged , , , , , | 1 Comment