Plug Flow Reactor - Technical Information
The plug flow reactor simulates a tubular chemical reactor by solving the heat and material balances based on supplied reaction stoichiometry and kinetic data.
The reaction stoichiometry must be defined in the Reaction Data Sets Window before the reactor performance can be specified. Kinetic data may be entered in the reaction set or in the reactor unit operation. Data entered in the unit operation override data entered in the reaction set for that unit only.
Calculation Method
The plug flow reactor models a tubular reactor and assumes that there is no mixing as the material moves along the length of the tubes. The conversion depends on the reaction rate and the residence time of the reactants in the reactor. The reactor geometry must be defined in order to determine the residence time.
The rate of a reaction is calculated by the Power Law Rate Equation:
For example, in the reaction:
then, 
where
, etc. are the activities of components A, B etc.
You may express Activity as Activity Coefficient, Molar Concentration, Fugacity or Partial Pressure.
When only library components are present, heat of reaction is normally calculated by PRO/II from heat of formation data. Alternatively, heat of reaction data may be supplied in the Reaction Data - Heat of Reaction Data Window. If non-library components take part in a reaction, either heat of formation or heat of reaction data must be entered.
By default, the reactor operates isothermally at the feed temperature. Alternative thermal specifications are:
fixed temperature
fixed duty
external heating/cooling
defined temperature profile
The plug flow reactor does not support rigorous modeling of two liquid phases. VLLE thermodynamic are not applicable for this unit.
Feeds and Products
The plug flow reactor unit can have any number of feed streams. The inlet pressure is taken to be the lowest pressure of all the feed streams.
The reactor can have up to four process product streams, with each stream containing a different phase. The possible phases are vapor, liquid, decanted water, a mixture of liquid and vapor, and solids. If there are multiple product streams leaving the reactor, the phase condition for each stream must be specified using the Product Phases Window.
