using solids

[HenkF]

First of all, to Jasper and collegues: great job! Some time ago I already ran into COCO, but did not actually use it. The past few weeks I started to exploring COCO, and... I'm really impressed! Especially by the flowsheet in flowsheet and Excel UOP possibilities. A question regarding the use of solids in a simulation. You have defined some in solids.pcd. I like to use solids in a simulation, e.g. to simulate the burning of wood. I did succeed in importing gas and liquid compounds, defined a property package, and used that in a simulation. I have to explore the property methods, but so far so good.

When I try add a solid compound - let's take iron- , some warnings show, and I am unable to add the solid data to the property package.
The warnings are :
* No data for Antoine Equation for liquid vapor pressure,
* No data for temperature correlationfor pure liquid surface tension, and
* No data for Hankinson and Thompsonfor liquid density

I guess I won't need these data for the simualtion, or should I enter a dummy value? Which compound constants and temperature correlation data are needed to use a solid compound in a simulation? Relating to using solids: is it possible to define and use a solid gas reaction: eg the C(s) + O2(g) => CO2 (g) in the fixed conversion reactor?

A small issue I ran into: when using a flowsheet as a UOP, I defined external parameters to be used at a higher level. I seems that the parameter name instead of the exported name is exported. Not a big issue, but convenient if more UOP's of the same types are used.

kind regards
Henk Fikkert

[jasper]

Thank you for your nice comments.

The solids implementation in TEA is very simple; solids are only supported in the solids phase, and nothing else is supported in the solids phase.

This restriction is one that holds for TEA only of course; you could use a different thermodynamics package that has better support for solids, and COFE/COUSCOUS etc would operate fine with that.

The Antoine equation data missing is not a problem for a solid-only compound. In fact, this warning got removed in TEA 2.5.0.3 which is available via CUP (well - 2.5.0.4 by now that is).

The other two warnings should appear only for compounds that are not marked as solid. But I see indeed the behaviour you report. This is a bug, now it is fixed.

The fixed conversion reactor will perform its conversions on the overall phase, irrespective of which phase is identified as the reaction phase. It will produce warnings in doing so though - just to make clear that this is the case.

As an alternative, you can rather easily define reactions between such compounds in the Matlab or Scilab unit operations (or the Excel unit operation). All are available from http://www.amsterchem.com/

The parameter exposed name: yes - I see. Fixed now (CUP).

Thank you for reporting these issues.

[HenkF]

Hi Jasper, thanks for your swift response and updates!
I already have been playing around with the Excel add-in, which may just provides the missing links.Frankly : I do not need the high geared Hysys or Aspen Plus solutions. Just proper mass- and energy balancing, and if needed some more detailed models, already brings a lot: insight in my processes and awareness of the influence of recycle streams to my processes. So, I'm very happy with the solutions you offer, and know where to find you when additional support and modelling effort will be needed.
Again, many thanks!
Henk

[jasper]

Glad to hear it.

Note that using the Matlab or Scilab unit operations allow for fairly easy custom modelling.

http://www.cocosimulator.org/down.php?dl=AIChE_Chemsep_COCO_FormulaBased_2010_slides_and_notes.pdf

(the corresponding flow sheets are in the examples section on the COCO web site)

And of course the CAPE-OPEN interfaces themselves allow you to add unit operations of your own making.

http://www.cocosimulator.org/index_support.html (go down to: How to I add user defined unit operations?)

[HenkF]

So far, so good! Managed to enter values for user defined solids, and use them in a simulation succesfully. E.g. using the Fixed Conversion Reactor shows reasonable similarity in results, when compared to the reference software: an adiabatic temperature rise difference of ~4 degrees (1902 vs 1906 C) when burning a wood constituent, which may be due to slight differences in O2, N2, H2O and CO2 basic data values (which are from a different data source than TEA). Although some extensions are still needed, this end seems to be covered.
I'm aware of some limitations of COCO, but still... very happy with it's possibilities!
Another question regarding solids usage : are there any thoughts regarding implementing particle size distributions (PSD)? Could I mimic such a behaviour by defining different phases for each PSD interval?
regards, Henk

[jasper]

There is an official extension to the CAPE-OPEN interfaces that deals with particle size distributions. This deals not only with particle size distributions, but also with distributions of other properties over particle size distributions (e.g. moisture content, in drying processes). This leads to tensors of distributions that live on material objects (streams). This would only be useful if this goes hand-in-hand with the unit operations that operate on such distributions. So far nobody has requested such functionality on COFE and COUSCOUS.

I suppose you could mimic N solid phases, each of which represents a particle size, but the division of species over phases is typically done by the equilibrium calculation of the thermo, whereas particle size distributions are typically predicted by unit operations. It seems more plausible to assign a compound to each particle size interval. The overall composition is predicted by the unit operations (and specified at feeds), exactly what you want, and if you make these solid-only compounds TEA will happily all put them in a single solid phase for you.

[colancto]

The CO standards extension Jasper is mentioning was implemented in SolidSim, a process simulator dedicated to modelling of processes involving solids and developed at Technical University in Hamburg-Harbug (Prof. Werther's team). After the R&D done at TUHH, SolidSim was further developed in a small company known as SolidSim Engineering which was bought last year by Aspentech. You may find most of the unit operations models dedicated to solid handling developed within SolidSim now in Aspen Plus.

[colancto]

The CO standards extension Jasper is mentioning was implemented in SolidSim, a process simulator dedicated to modelling of processes involving solids and developed at Technical University in Hamburg-Harbug (Prof. Werther's team). After the R&D done at TUHH, SolidSim was further developed in a small company known as SolidSim Engineering which was bought last year by Aspentech. You may find most of the unit operations models dedicated to solid handling developed within SolidSim now in Aspen Plus.

[HenkF]

Thanks for your replies. In the past I've used Aspen Plus, and it's possibilities to enter phase attributes, PSD and other solid specific information.
Unfortunately Aspentech now indeed has taken over the SolidSim company...
regards, Henk

[Ronny]

Hello Jarper and Team

I'm trying to run the fixed bed conversion C(s)+O2(g)->CO2(g), as HenkF did some time ago in this post, therefore I have to include a solid in the flowsheet.
In TEA, the thermo pack has C(solid-only), O2 and CO2; Some warnings, but no problems to save the thermo pack.
On COFE, I'm trying to have both components in a single stream (C(s) and O2(g), and the simulation shows the following error (streams are red) "Failed to calculate stream 1: CalcEquilibrium failed: TP flash failed:Failed to set vapor fhase fraction:Cannot set phaseFraction on two-phase specifier"
Most likely the setting I have made have some issues, it's maybe trying to calculate phase equilibrium with solids. Is there any special restriction when dealing with solids-only components?

Best Regards,
Ronny