Thanks for your valuable comments! I am tending to follow Roker's advice as this approach is certainly on the safer side and makes sense on a thermodynamical understanding, even if it's not required by API 521 as Pleckner mentioned!
Recently I joined a discussion about safety considerations for external fire scenario. When calculating the wetted surface for protecting the tube side of an heat exchanger it was discussed whether to include the shell surface and the heads or whether to include just the head surfaces. There...
For rounding up potential solvent candidates you could contact the Dortmund Data Bank. They provide thermodynamic and transport properties of pure components and mixtures as well as special programs for data correlation, estimation and process synthesis. Part of their software package is a tool...
I understand you are aware of how to design a cyclone following the equations of e.g. Barth and Muschelknautz which are the basis for a proper design. However, those equations do not give any hints about common relative proportions of cyclones.
Here are some rules of thumbs which can be found...
If your unit is using NMP as a solvent in an extractive distillation process it might be more economical to recover the NMP for reuse in your process.
Recovery of NMP is usually done by distillation. Depending on your exhaust stream and process this can be done by a small additional tower or...
Sshep,
I was indeed thinking about scaling up fouling factors based on a time interval. Or rather if the given fouling factors are appropriate for TAR intervals of 5-6 years.
Your statement gives me a better feeling of what is appropriate and what not.
Thanks to all of you for your valuable...
Thanks for the operational advices. I agree that those values are not set in stone and strongly process dependent. There is big influence of fluid velocity, temperature, heat flux, fluid composition and construction of the exchanger. Sometimes fouling is quite linear or asymptotic and sometimes...
Fouling factors are used to provide added heat transfer surface area. This means that the exchanger is oversized for clean operation and barely adequate for conditions just before it should be cleaned. TEMA and other sources provide values for fouling resistances "so that the exchanger will meet...
Guidoo,
I agree with everything you write but I have one question concerning the reliability data of safety valves.
I know that some companies use a PFD (probability of failure on demand) factor of 0.01 (which comes up to a failure of 1 per 100 demands compared to 1 per 1000 demands in your...
