It’s a simple question – how to solve it
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Either ASPEN or HYSYS can be used to simulate a simple feed scenario: propane enters a container in a supercooled liquid state. Ideally, the container should reach the equilibrium pressure of propane at that temperature automatically. However, when conducting the simulation, it is necessary to specify either the pressure, temperature, or gas phase fraction of the container; otherwise, it is not possible for the propane to reach the equilibrium pressure at that temperature once it enters the container
To simulate such problems in ASPEN or HYSYS, it is usually necessary to select an operating strategy to determine the conditions inside the vessel. If you want propane to automatically reach its equilibrium pressure at the subcooled state upon entering the container, I recommend taking the following steps: 1. Find or calculate the saturated pressure of propane at the known subcooling temperature (through literature or using the property calculations built into software). 2. In the simulation, set the operating strategy for the container to fixed pressure, using this saturation pressure as the initial pressure of the container. 3. Feed propane into the container as supercooled liquid. Since the container pressure has been set to the saturation pressure of propane, theoretically the material will gradually reach an equilibrium state at that temperature and pressure once it enters. 4. Perform simulations and observe whether the substances inside the container have reached the desired equilibrium state. It should be noted that the initially set pressure may need to be fine-tuned based on the simulation results to ensure the accuracy of the simulation. This method allows you to control the initial conditions of the container, so that they correspond to the behavior of propane in actual processes. In practice, fine-tuning of the pressure may be necessary, as there are always differences between the simulated environment and the actual environment. .
In this way, it’s as if the container pressure is set manually; if I change the propane feed temperature, the container pressure still won’t automatically reach the equilibrium pressure corresponding to that propane temperature
Setting the container pressure to 0 and the load to 0 should achieve the desired effect
It is recommended to use the first circular module in the heat exchanger, set the first temperature, and set the second vaporization fraction to 0; this will give the equilibrium pressure at that temperature