The relationship between stdvol and volune in Aspen
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Regarding the relationship between stdvol and volume in Aspen Plus, I previously looked up information online; it is said that stdvol represents the volumetric flow rate under standard conditions, while volume represents the volumetric flow rate under the current input conditions. However, when I used Aspen to run simulations with temperature and pressure set at 1 atm and 0°C, and entered stdvol as 100 cum/h and volume as 100 cum/h, the simulation results showed two different flow rates. Is there an error in my input values for the simulation, or is this explanation itself incorrect?
The standard liquid volume flow (Stdvol-Flow) can be very different from the volumetric flow rate of a fluid stream. The standard liquid volume is defined at approximately 60°F and 1 atm; the difference between the two values increases as the operating conditions deviate from these values. If the fluid is a vapor or contains a significant amount of vapor, its volumetric flow rate will be extremely different from the standard liquid volume flow. Standard vapor volume flows can be entered as mole flow rates; select the appropriate units for this purpose. To include information on Std.liq.Volume Flow or Std.liq.Volume Fraction in the flow rate report, choose the relevant options on the Setup Report Options Stream sheet. These property values can also be calculated: ?VLSTDMX (standard liquid volume of a mixture), ?VLSTD (standard liquid volume of a single component). StdVol-Flow and StdVol-Frac are variables that can be utilized in design specifications and calculator blocks.
stdvol and vol are different; the former seems to refer to the volumetric flow rate of the liquid at 60F, while the latter refers to the flow rate under those same conditions. You can view the help file