Questions regarding the reaction heat simulation in ASPEN
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Hello everyone, I would like to use ASPEN to calculate the reaction heat. Some people say that it can be calculated by the enthalpy difference of the incoming and outgoing materials, or through reaction heat calculation reports. However, the value obtained for the reaction heat is pretty much the same as the theoretical value, while the enthalpy difference of the incoming and outgoing materials is 0. Since the reaction is exothermic, I really don’t understand why the enthalpy values before and after the reaction are equal. Thank you! The attachment are two screenshots.
Hello! In ASPEN simulations, if the calculated reaction heat is close to the theoretical value but the enthalpy difference of the incoming and outgoing materials is 0, this may be due to some issues in the simulation settings. First, ensure that the temperature, pressure, and composition of your feed and product streams are correctly set in the simulation. Furthermore, check whether you are using an isenthalpic reactor model and whether the system settings take energy balance into account. It is possible that the simulation assumes that all the heat generated during the reaction is absorbed or released by the system, resulting in a enthalpy difference of 0. It is recommended to check the settings or try using other types of reactor models for simulation. I hope this information is helpful to you! .
Hello, thank you for your reply. I think it doesn’t matter which type of reactor is used; I chose an adiabatic reactor, in which no heat is lost. Therefore, the heat release should be reflected in the enthalpy values at the inlet and outlet – that is, the enthalpy at the outlet should be higher than that at the inlet. However, this does not happen; the enthalpy values at the inlet and outlet are equal. I’m really confused by this.
By calculating based on the reaction equation, it should be possible to identify where the problem lies.
In an adiabatic reactor, the enthalpy of the inlet material must be equal to that of the outlet material