ChemE.info – Chemical Engineering Consulting

I should state at the outset that I know little about the current state of CAPE OPEN and how well it is serving the process industries. (If someone wants to send me their comments on the current state of CAPE-OPEN, I will be happy to append it here).

CAPE-OPEN

My feeling is that the CAPE-OPEN initiative came about to address some key concerns of the “consumers” of process simulation software. These concerns were as follows:

• What happens to my considerable investment of time and effort in developing models of my plants and processes if the vendor of my commercial simulation software goes out of business?
• What happens if the vendor of my commercial simulation software decides to jack up the license fees higher than I can afford or think is reasonable?
• What happens if the vendor does not choose to add features to the simulator that I feel are necessary?
• What if the vendor does provide adequate levels of customer support and/or the simulator is too buggy.
• What happens if my simulation vendor is merged with another vendor and my simulation software is no longer going to be supported or further developed?

All of these boil down to the issue of “vendor lock-in”. If you spend man-decades developing models of your plants and processes… And those models are important to your continuing operation and improvement of said plants and processes… And you are licensing your simulation software for some set period… Then your vendor has you over a barrel.

The vendor knows there is a large barrier to your switching to a competitor’s product… Your engineers would need to be retrained and every one of your models would have to be redeveloped from scratch for the competitor’s simulator. So the vendor’s sales department will tend to increase there prices at license renewal time to just short of the excruciating point that you will “bite the bullet” and switch.

My impression was that CAPE-OPEN was developed by the process industry consumers of simulation technology to try and reduce that barrier to switching simulators. The idea being to develop a standard way of representing a process, its chemical components, unit operations, and connectivity and requiring all the commercial simulator vendors to add interfaces to their software that would both generate and read process descriptions that obeyed the CAPE-OPEN format.

As an example of how this might work… Let’s say my company has built a model of a vinyl chloride plant using ASPEN PLUS but we are no longer happy with AspenTech… According to CAPE-OPEN, we should then be able to tell the ASPEN PLUS software to generate a complete, vendor-neutral, CAPE-OPEN representation of our VCM process.

We then license, say, PRO/II. According to CAPE-OPEN, we should be able to tell PRO/II to read the CAPE-OPEN representation of our VCM process. We then push a button,and “poof”, we run our first PRO/II simulation. Should only take a few minutes and now all we need to worry about is learning how to use the PRO/II interface.

Unfortunately, I doubt it is (or ever will be) that simple… For a variety of reasons:

• The CAPE-OPEN interfaces are being developed by the simulation vendors. It really isn’t in their interest to have it work and their support of the initiative will be grudging at best.
• You are getting out of the frying pan and into the fire. OK, say you can generate a vendor-neutral process description. Which vendor’s simulator are you going to read it in to? None of the simulation vendors are doing well financially; none seem to be well managed; none are serving their customers well.
• Getting a model of any complexity to work in any simulator is challenging and there will always be subtle or not-so-subtle differences in how each simulator represents and converges a given flowsheet or piece of equipment.

[Again, if anyone wants to email me their experiences as a user of CAPE-OPEN I would appreciate it.]

OPEN SOURCE

I don’t think the term OPEN SOURCE had even been coined back when CAPE-OPEN began but, in hindsight, I think pushing for the development of one or more OPEN SOURCE simulators would have been of much greater service to the process industries. These could have been (can be) developed from scratch or created by converting an existing commercial/closed-source simulator to be open source. We have seen examples of the latter in recent years in Sun’s “open sourcing” of Solaris and Java.

Please note that Open Source does not simply mean providing or using software for free. There are costs associated with using Open Source software… It is simply a different business model and there are quite a number of successful companies that are making money while writing or supporting open source software (e.g. IBM, RedHat, Sun, Novell, etc.)… And thousands of companies and government agencies happily using Open Source software such as the various flavors of Linux, Apache, MySQL, etc.

I see some huge potential advantages for the process industries if one or more open source process simulators were to be developed:

• Users would no longer at the mercy of the vendor’s salesmen and lawyers when it comes license renewal time… There would be no license in the old sense. What would be negotiated would be a service contract and if user was not been happy with the service they would be free to walk without losing access to the simulation software.
• The user would no longer be subject to the vendor’s development priorities. A vendor may (quite legitimately) feel that some requested capability is not widely applicable to the general customer base and therefore not worth developing. But, with an open source arrangement, the user(s) who need the capability could develop it themselves or comissions a third-party to develop it.
• And with open source simulators there would be a cottage industries of individuals and companies developing, implementing, and supporting the products.
• The user community is always in a position to judge the code quality and architecture of the simulator because a wide community of programmers, engineers, and consultants can see the code for themselves.

As far as I know there are no general purpose open source process simulators available or under development at this point. (If anyone knows of any, please email me and I will amend this section). Virtual Materials (a physical properties software outfit up in Calgary) made an effort at this with a simulator called Sim42 but, unfortunately, they did not get any response from the commercial user community and the effort was suspended. There is successful, actively used and developed, open source process-related software such as Cantera (for simulating reacting systems) but they all seem to be limited in scope and focus and I am aware of no general purpose simulators.