Professionally I work at BPT and focus on creating value adding App for Process Simulation. You can find more info on those on the BPT website. Below are posts that should help HYSYS, PetroSIM and UNISIM users alike in their day to day challenges to produce accurate yet fast models efficiently.

Release the true potential of your staff Apps for Process Simulation

Monday, 30 March 2015

Did you know series: When using Lee-Kesler Enthalpies with the PR EOS, you get better enthalpies AND ASME steam enthalpies for water as a bonus

The vast majority of Aspen HYSYS simulation cases is using the Peng Robinson equation of state. The default enthalpy method when you select to use the Peng Robinson EOS is the enthalpy of the EOS itself. And that is what the majority is using. This is typically not a conscious selection, it is just that people go with the default. To use Lee Kesler enthalpies in version V8.x should be self evident, it is on the same page where you select the EOS. If you still use V7.3, then you should go to the Parameters tab after selecting the EOS, there you can choose the enthalpy method.

You really should go for Lee Kesler enthalpies. I do not have hard evidence in this post (literature comparisons or so), but even a quick search on the internet will yield literature references that confirm this. There are also conversations I had with users that are a pretty good indicator. Some people emphasise the benefits for cryogenic systems, others recommend Lee-Kesler more generally. There is also some recent work I did on modelling turbo expanders that clearly showed that the Lee-Kesler enthalpies matched vendor performance data much better.

And, there is a little bonus that is probably not so well known: When you select Lee Kesler enthalpies, HYSYS will look at your stream composition and if it is all water, it will use the ASME steam tables. Even at standard conditions, the error on PR EOS duties is about 3.5% and this grows worse as you go to higher pressures. So, if only for this, selecting Lee Kesler Enthalpies is a good thing to do.

Saturday, 21 March 2015

Did you know series: Is V8.x eating your screen real estate? The "Send To" function comes to the rescue!

I am pretty sure that you also have the impression that with the advent of version V8.x your screen has all of a sudden become way too small. And I have heard on enough occasions that a second screen is a luxury only reserved for designers. Fortunately, the Send To function introduced with version V8.x really helps.

In any view you can right click on some input or result and get a context sensitive menu with as one of the options: "Send To". This option lets you send the selected bit of information to Case Studies, Data Tables, Spreadsheets or Strip Charts. These can be existing objects or you can select to create a new one.

The send to is really useful because you do not need to have the view of the case study or spreadsheet open, you only need the view of the item you want to send.

With V8.6 have come some improvements. When you send an item to an existing spreadsheet, you'll get a chance to indicate where you want the item to go and there will be an indication which cells are already taken. That makes this a very handy way to add data to spreadsheets. There are a couple more features that you might not have expected:

  • You can send an input, say a stream mass flow, to a cell that contains a calculated value and this will export the formula result to that input.
  • You can select a range of values, a composition for example, and send the whole range to the spreadsheet! Make sure your spreadsheet can handle all the data!
Have a play with this new feature, it will make your life a lot easier!!!

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