No replies to this topic

[C_Brooks]

Hi guys! Sorry if this is a simple question, but I'm just learning how to use ChemCAD. I have a simulation of a power plant secondary loop (just the Rankine Cycle) and I want to try to add a thermal storage system to it. I have all the equipment placed, but here's the problem I'm running into. It's a dynamic process which involves some streams running at some times but then not at other times (basically I just open and close valves to get the flow where I wish). But there are a few heat exchangers in the process that are bypassed or only have one stream flowing through them. ChemCAD does not seem to like this; it tells me that I need to specify conditions for the heat exchangers, but specifying outlet temperatures or heat duty is impossible if there's no flow in the first place! I'm particularly concerned about one specific heat exchanger that's totally bypassed unless the storage system is discharging (adding heat back into the process).

 

So my questions are:

1) How do I convince ChemCAD that I don't need to specify any properties or exit conditions for the heat exchanger for the present simulation, since it will be bypassed on both sides?

2) How do I inform ChemCAD that certain streams are going to have a flow rate of zero in the present simulation?

3) Where can I go to get a better idea of how to run a dynamic process in ChemCAD in general (I'd appreciate some kind of tutorial here rather than a simple link to CC-Dynamics help; also note that my process is only dynamic because the fluid levels change in holding tanks, so I don't have either a batch reactor or a column, which are the two focuses of CC-Dynamics in the first place)?

 

I can also upload the process flow sheet if you would like.

Thanks!

Chris