Help: Why is the cooling heat load calculated for the mixed gas using the heater so different from the theoretical value?
Thread Content
Cooling semi-water gas with cold water yields significantly different results; could experts advise on which property method should be used?
Composition of semi-water gas (volume percentage): Components – CO2, CO, H2, N2, Ar, CH4, O2. For inhalation at Level 1: 7.55, 29.90, 38.29, 22.72, 0.30, 0.94, 0.30. There is also some water vapor present. When performing heat calculations using Aspen, which property methods should be used to obtain accurate simulation results? I am just starting to learn the Aspen software, and I earnestly ask for your guidance from all of you experienced users.
Reply to 2# TOBEKING: For thermodynamic systems, RK is sufficient. The large errors in heat calculation are likely due to the fact that ASPEN’s default method for calculating enthalpy relies on equation of state calculations; you can try using the DIPPR liquid-specific heat capacity reference method. http://bbs.hcbbs.com/viewthread.php?tid=877435&highlight=%B1%C8%C8%C8%2Bcl6119
Reply to 3# cl6119: Thank you very much for your help. I performed the calculations using a gas mixture that did not contain water vapor, and the values obtained were not very different from those obtained earlier; they still differed significantly from the manually calculated values. I am currently using Aspen EDR to design heat exchangers, but the specific heat of the gas side is inaccurate, which prevents effective design. How can this be adjusted in EDR to improve the situation? Waiting online
The physical properties in EDR can be entered directly: select the checkbox that prevents recalculation of physical properties, and enter the values you consider accurate for those properties.