Regarding the effect of the in situ separation, the model was also used to estimate the molar flow rate of NH3 using reactor configuration d). Therefore, NH3 sorption was assumed ideal in the model. Hence, a complete removal of NH3 is considered at a defined location of the catalyst bed at 𝑧 = 𝑧 , where the sorbent bed divides the catalyst bed. In other words, the separate modelling of the sorbent bed is omitted since sorption is assumed ideal. Therefore, Eq. ( ) is appropriate to calculate the axially distributed molar flow rate of NH3. However, at 𝑧 = 𝑧 the ideal removal is considered by using Eq. .