Constant Pressure Mole Reactor#

A constant pressure mole reactor is implemented by the C++ class ConstPressureMoleReactor and is available in Python as the ConstPressureMoleReactor class. It is defined by the state variables:

  • H, the total enthalpy of the reactor’s contents (in J)

  • nk, the number of moles for each species (in kmol)

Equations 1 and 2 below are the governing equations for a constant pressure mole reactor.

Species Equations#

The moles of each species in the reactor changes as a result of flow through the reactor’s inlets and outlets and production of gas phase species through homogeneous reactions and reactions on the reactor surfaces. The rate at which species k is generated through homogeneous phase reactions is Vω˙k, and the total rate at which moles of species k changes is:

(1)#dnkdt=Vω˙k+inn˙k,inoutn˙k,out+n˙k,wall

Where the subscripts in and out refer to the sum of the corresponding property over all inlets and outlets respectively. A dot above a variable signifies a time derivative.

Energy Equation#

Writing the first law for an open system gives:

dUdt=pdVdt+Q˙+inn˙inh^inh^outn˙out

where positive Q˙ represents heat addition to the system and h is the specific enthalpy of the reactor’s contents.

Differentiating the definition of the total enthalpy, H=U+pV, with respect to time gives:

dHdt=dUdt+pdVdt+Vdpdt

Noting that dp/dt=0 and substituting into the energy equation yields:

(2)#dHdt=Q˙+inn˙inh^inh^outn˙out