Questions regarding multi-stage compression modules and single-stage compression modules
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Recently, during simulations, I found that when the outlet temperature is first calculated using single-stage compression and then the outlet temperature and compression pressure are determined using multi-stage compression, the resulting work values differ, with the isentropic efficiency set at 0.85 in both cases. I was wondering if others have noticed this as well; what could be the reason for this?
Theoretically, that’s how it is. Multi-stage compression saves energy. It’s not an Aspen issue. It is recommended to find a book on basic theory and read it.
Reply to 2# gust111: Yeah, could you recommend some books? When setting up multi-stage compressors, if the heat duty is set to 0, the outlet temperature differs from that of a single-stage compressor (with the same outlet pressure setting). What is the reason for this behavior in Aspen?
Reply to 2# gust111: You are referring to the conditional version with an intercooler. Try it with air at two stages; it consumes more energy. Let’s also verify it using the single-stage adiabatic compression formula.
Reply to 4# rjb119: Do you know the reason for this?
Reply to 5# 2006140509: If you’re interested, check out the help documents.
For multi-stage compression, inter-stage condensers need to be installed, and this is the reason for saving W. If no out temp is set for the inter-stages and the duty is set to 0, theoretically the W value for multi-stage compression will be the same as that for single-stage compression
Reply to 7# fang*nhui: Well, theoretically it’s still close; the temperatures at multiple stages are higher, and the power requirement is also greater