[2026 Simulation Calculation] Application of the equilibrium module in Aspen Plus
Thread Content
This post was last edited by The one on 2026-5-21 13:08. Heat exchangers are the most common static equipment in chemical plants, used for heating or cooling materials as well as for energy recovery. In the actual operation of the factory, we need to adjust the heat exchangers appropriately according to the requirements of the upstream and downstream processes in order to meet those requirements; sometimes, when there is a change in the temperature or flow rate of one stream in the heat exchanger, we need to know the corresponding change in the temperature of the other stream. Theoretically, the above problems can be solved by combining the heat balance equations and the heat transfer rate equations, or by applying the number of heat transfer units equation; however, such calculations are time-consuming and labor-intensive, and the accuracy of the results is not high. Aspen Plus can be used to perform this calculation.
For example: Saturated steam at 1.0 Mpa is intended to be used to heat nitrogen for the regeneration of molecular sieves. The inlet temperature of nitrogen (C-IN) is 10°C, the pressure is 112 Kpa, and the flow rate is 1785 Kmol/h. The outlet temperature of nitrogen (C-OUT) is required to be 170°C; all steam must be condensed, with no supercooling of the condensate. Calculate the required steam flow rate and heat exchange area.
Step 1: Open the software, add water and nitrogen as components, select the P-R equation as the property method, and then establish the process as shown in Figure 1.
Step 2: Enter the inlet and outlet flow information for nitrogen and the inlet and outlet flow information for steam. For H-IN and H-OUT, only initial values need to be provided (any number greater than 0 will do).
Step 3: Enter the heat exchanger information; select the default method for calculating the heat transfer coefficient (U).
Step 4: Add the balance module B-1, and include mass balance and energy balance calculations. Under the “Calculation” option, select “C-OUT,H-IN,H-OUT”.