Dynamic Mass and Heat Balance Equations

The dynamic model equations are obtained by including the accumulation term in the heat and mass balances, presented in the previous section. Thus, the transient mass balance for the chemical species in the gas phase can be stated as follows  

From Equation 8.7, it can be noticed that gas velocity (Uq) is variable in the axial coordinate as a result of H2 consumption, H2S and CH4 generation, and thermal effect. An additional expression to estimate this parameter can be obtained by summing the transient mass balances of all the gaseous compounds (Schweitzer et al., 2010)  

Since gas volume is variable along the reactor, the constant pressure condition must be verified at every integration step. 

The dynamic concentration profile of the gaseous compounds in the liquid phase 

The transient mass balance for the chemical lumps in the liquid phase is the following  

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