Automation Apps, Gaming Systems and Thermodynamic Steam Quality

Readers Ask for Clarification on Some of Our Latest Articles

Do We Need an App for That?

I am the recent owner of an iPad, and I am sending this message as advice for you and your magazine.
I am an avid reader of technical and trade magazines. These things help keep me abreast of trends in technology in order to keep my company focused in the right direction. At 55 years old, it did not occur to me that I would ever give up my printed magazines for electronic versions, but it happened.

One of the first things I did with the new iPad was download Zinio, an electronic reader program. I now find it impossible to justify carrying printed magazines while I travel, which can be extensive at times. I read all my magazines, if they are available, on my iPad.

This allows me to keep many magazines with me at all times and past issues of those magazines for reference. I keep 20 or 30 magazines available, all in a package the size of one.

My disappointment is that not enough of my favorite technical magazines are available electronically. Please consider adopting this new technology for distributing Control magazine.

Rick Caldwell
President, SCADAware

[Editor's note: We always strive to deliver content in the most convenient way possible. We are researching this new technology now. To read the magazine online, visit to view all articles or download PDFs to your iPad's library.]

Gaming Systems

It's very interesting what Siemens is trying to do with Plantville (see Walt Boyes' SoundOff! blog post, It is a very tough balance to strike between engaging and real. Personally, as soon as I heard "KPI," I was done.

Autodesk recently launched an iPad app aimed at middle and high school students with the goal of introducing them to engineering and physics (see It is basically a graphical physics engine, plus a 2D Erector set that lets you create all sorts of simulated mechanical contraptions. Though it is aimed at older kids, my six-year-old absolutely loves this thing because to him, he is "making" something. The common refrain now after dinner is "Dad can I make something on your iPad?"

Autodesk has also created a short presentation and series of videos to be used at middle and high school career days. The main purpose is to show all of the amazing things people do with Autodesk software (from video games to process plants), and that it is all based on science, math and engineering. Apparently, the number of kids who "would consider careers in science and engineering" typically starts in the 10% or under range, but then moves to the over 50% range after the presentation.

Robert Shear
Business Line Director, Autodesk Plant Solutions

Missing the Point on Steam

In the April 2011 "Ask the Experts" column ("Measurement of Drift, Stability, Offset, Bias"), there is a question regarding steam quality. Unless I'm missing something, there appears to be a disconnect between the question asked and the answer provided. The question seems to be related to steam quality in the classic thermodynamic sense, i.e. the ratio of the mass of vapor to the total mass at saturation temperature; hence, the mention of a throttling calorimeter. When the term "quality" is used in this sense, it only has meaning when saturated conditions exist. Yet the answer provided speaks of superheated steam and seems to be related to steam purity, i.e. measurement of impurities in the steam.

Carl Foresti
Analyzer Reliability Engineer
ConocoPhillips Bayway Refinery

Béla Lipták's Team of Experts Replies 

I agree with Carl Foresti. "Steam quality" refers to the mass of water vapor at a given temperature compared to the total mass at saturation temperature.

When we talk about steam composition, the words "steam chemistry," and "impurities or contaminants in steam" should be used, especially in steam quality control programs (which actually means steam chemistry, not steam quality).

The following are quotes from "Interim Consensus Guidelines on Fossil Plant Cycle Chemistry," EPRI CS-4629, Project 2712-1, Final Report, June 1986, Sargent & Lundy, Chicago, Illinois:

  • P. S-1, "The Interim Consensus Guidelines contained herein are primarily based on current industry experience and well-established thermodynamic data that pertain to water and steam chemistry."
  • P. S-1, "These Interim Guidelines reflect a consensus of current state-of-art knowledge of International experience with cycle, water and steam chemistry control practices necessary to improve unit availability."
  • P. 3-21, "The target values for steam were derived based on turbine steam purity considerations and the solubility of major impurities in superheated steam near saturation."

Gerald Liu, P.Eng.
Calgary, Alberta, Canada

I used to teach Mollier Diagrams in thermodynamics. We would show an adiabatic process from a steam line with saturated steam that dropped the pressure (through a throttling calorimeter) at constant enthalpy to a superheated state. We located the exit state and traced at constant enthalpy back to the pressure in the saturated region to get the quality. Thus, the responder is sort of correct.

When you use a throttling calorimeter to get the quality of saturated steam, you will exit the calorimeter with superheated steam at a lower pressure.

Constant enthalpy is achieved by having just an insulated line, a valve and thermometer well. The entropy of the steam increased because it is a highly irreversible process. You know the pressure (ambient) and temperature at the exit. You trace back on a diagram or with steam table software to the same enthalpy and pressure in the line. The saturated steam tables will then have the quality, or you can calculate it from properties such as specific volume actual and the reference specific volumes of the saturated liquid and vapor phases.

Morton Reed

[Editor's note: The following letter came to our sister site,, which linked to Béla Lipták's "Lessons Learned" column for May 2011  on the Fukushima nuclear plant disaster.]

Fukushima: What Went Wrong?

Thank you for the coverage of the nuclear plants in Japan. Because I live in Hawaii, I've been watching the stories on TV and reading news coverage. As a chief engineer and thinking from an operations design perspective, it brings back some heated meetings in which we asked for items about which the design engineers fought us tooth and nail.

Their argument was that these things weren't necessary for normal operation, and we were asking for things that just cost more money and were not needed.  I remember one event with GE, where they did not even come close to what we had asked for, and this came to a point where we wanted to drop them as non-compliant. It had nothing to do with anything but cost, and they were right that the design would work in normal operation, but it had almost none of the redundant designs that we'd asked for.

Béla Lipták, PE, wrote some of the best articles I've ever seen about the conditions and points that could have helped at Fukushima ("The Fukushima Nuclear Accident - Part 1".) As someone who lived through concept, design, construction, commissioning and operations, I can see exactly what he's saying. I too thought of many things that an outsider can see that would have prevented or controlled the events. I agree up to a point that no one could have envisioned all the events—or could they?

I have seen or read nothing of any meeting about preparing for such events, even though we know about earthquakes and tsunamis, and have known for years. Why wasn't a team of  plant engineers, operators and designers of modern power plants put together to address the already known design questions? Even if there were, there should have been a report of design ideas made public, so people living around the plants could feel more comfortable that something like this would not happen. I know hindsight is always better, but here is a case where people like myself could provide input to help and be a part of a team. No one set of eyes can see it all, but most of the time, it just comes down to dollars.

What came to mind was our company's jumbo ferry project. Because it was for a passenger vessel, and a situation you never want is the ship in the dark or dead in the water, we named things that we wanted the ship run without—rather that just what the regulations said we had to do. Maybe it is time for a similar group for nuclear power plants.

Clark Dodge
Owner/President, CED Consulting LLC

In our May cover story, ("Distributed Safety Arrives"), the number of installed DeltaV SIS systems was misstated. The online version has been corrected. There are over 700 systems, of which 170 are distributed. We regret our lack of clarity.

Show Comments
Hide Comments

Join the discussion

We welcome your thoughtful comments.
All comments will display your user name.

Want to participate in the discussion?

Register for free

Log in for complete access.


No one has commented on this page yet.

RSS feed for comments on this page | RSS feed for all comments