Patent Document ID: 4053743
Application ID: 05658897
Patent Flag: 1

Claim One:
1. A method for controlling concentration variables of process material in a chemical reactor containing reactants which reach thermodynamic equilibrium substantially simultaneously, the reactor having at least one process inlet flow through the inlet, one process outlet flow through an outlet, and one control inlet flow, further at least one desired outlet concentration being provided, the method comprising the steps of: a. measuring the concentration of at least one reactant of the process material in the process inlet flow, and the concentration of a reactant of a control material in the control inlet flow; b. providing a residence-time distribution function for the process material flow from said inlet to said outlet, and a residence-time distribution function for the control material flow from said control inlet to said outlet; c. calculating an apparent outlet concentration of said at least one reactant of the process material and an apparent outlet concentration of said reactant of the control material with the aid of the respective measured inlet concentration and the respective residence-time distribution function in accordance with the following relationship: ##EQU7## g = residence-time distribution (weighting function) C.sub.i = concentration of component i in the outlet channel C.sub.in = inlet concentration t,0 = time variables d. assuming thermodynamic equilibrium and utilizing said provided desired outlet concentration of the preamble as well as said apparent outlet concentration of said at least one reactant of the process material in step (c), calculating a desired apparent concentration of said reactant of the controlled inlet flow at said outlet; and e. controlling the control inlet flow by means of a feedback control, like a proportional, integral and derivative PID control, on the basis of the difference between said apparent outlet concentration of the control reactant in step (c) and said desired apparent outlet concentration of said control reactant in step (d).