HYSYS dynamic simulation shows that during the filling process of the hydrogen tank, the tank temperature does not rise but instead decreases
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I’m confused. I’d like to ask the experts: why, when using pure hydrogen as the feed gas in the dynamic simulation of tank pressurization, does the tank pressure decrease instead of increasing?； When a mixed gas is used, the temperature of the storage tank rises. I’ve placed the model here, hoping to get some guidance from the experts. Brief description: Set the initial pressure of the feed gas to 8 MPa, and set the pressure of the flow control tank at 35 MPa when it is activated.
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In principle, it should indeed rise
I am also involved in the pressurization process of hydrogen tanks, and I encountered the same issue. Has the original poster managed to solve their problem?
For example: when the total enthalpy of hydrogen is -2950 KJ/KMOL, the temperature of -75.62 serves as the critical point, with a corresponding pressure of 17.85 MPA； Starting from this point, the lower the pressure, the lower the temperature; the higher the pressure, the lower the temperature as well (with constant enthalpy). You can consider the final state and the initial conditions as a situation where the total enthalpy remains constant; taking into account the remaining gas in the tank as well as the gas that is added later, it’s equivalent to adiabatic compression. In such a case, the condition should be on the right side of the boundary point – that is, the higher the pressure, the lower the temperature. For other gases, he has not yet reached this threshold, where the higher the pressure, the higher the temperature.
I saw this image in a video today, so I’m sharing it with you! Also, what I typed above – the pressure value is incorrect; it should be 1.785 MPa
I still don’t understand. Is there a way to deal with it?
Has the original poster solved it? I’ve encountered similar problems too
I understand this principle as well, but the opposite happens during simulation; do you know how to solve it?