Simulation model

The two adsorption beds are identical. We model the adsorption beds according to the following specifications:

• We use one (NLayers = 1) BedLayer submodel with 40 segments (Layer[1].Ne = 40) of alternating bed and wall elements.

• We calculate the pressure drop according to Ergun3 (PressureDrop = Ergun).

• We create copies of the RatesLocal, RatesLDF, IsothermInert, and IsothermExLangmuir submodels from the Adsorption library in the simulation-specific library. Then, we update the rate expressions, saturation concentration calculations, and equilibrium loading calculations to match the empirical data that we have for our alumina adsorbent.

• We use the RatesLDF submodel from the simulation-specific library to calculate the adsorption rates of N2 and O2. These linear driving force (LDF) rate expressions are based on the paper by Farooq and Ruthven1.

• We use the IsothermExLangmuir submodel from the simulation-specific library to calculate the saturation concentrations and equilibrium loading. We calculate the equilibrium loading by using the Extended Langmuir equation.

• We model the outlet valve by using a first-order time constant (Tc) of 0.02 seconds.