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Update: Variables Constraints


Here's important information regarding the product stream constraints. Please read this blog post carefully and make sure you have this information in mind when submitting your results.

The constraints for the input variables are not the only thing to watch out for when searching for good solutions. It is just as important to fulfill the product specifications!

In order to feed the bio-gas to the existing natural gas infrastructure it’s Methane content has to be above 96 mol% to achieve a sufficient heating value. However, this constraint is not too critical so that we allow a deviation of 0.1 mol%.
This does not apply to the H2S constraint. H2S is highly toxic and corrosive:

  • 0.00047 ppm or 0.47 ppb is the odor threshold, the point at which 50% of a human panel can detect the presence of an odor without being able to identify it.
  • 10 ppm is the OSHA permissible exposure limit (PEL) (8 hour time-weighted average). OSHA is the U.S. Occupational Safety and Health Administration.
  • 10–20 ppm is the borderline concentration for eye irritation.
  • 20 ppm is the acceptable ceiling concentration established by OSHA.
  • More information can of course be found here.

That is why we decided to limit the H2S concentration in the product stream to 20 ppmNo tolerance is given here!

In order to make it easier for all participants to keep all the restrictions in mind, we included a little table into the newest version of the flowsheet. It shows you whether your current solution is fulfilling the product constraints.

In case you have any additional questions, let us know at team [at] process-simulation-cup [dot] com or ask us on facebook!

Good luck everyone!

Process Simulation Cup Team

28 June 2016