Abstract: A process for maintaining an optimum polymerization process in a continuous loop polymerization reactor by driving a catalyst feed range set-point around a bad catalyst set-point range using a bad catalyst feed rate program to vary the catalyst feed rate for differing periods of time between previously determined good catalyst feed rates.

Abstract: A process and system for maintaining optimum polymerization production in a loop polymerization reactor by continuously and periodically obtaining polymerization results, such as melt index (MI), production rate and ash content of the polymer produced, determining whether each of the results is within desired ranges, storing and averaging recently obtained results in a database within a reaction rate controller program, and when one of the results is out of the desired range modifying at least one reaction parameter set-point such as monomer concentration, catalyst feed rate and reactor temperature to drive any out-of-range polymerization result(s) toward the desired range for that result.

Abstract: A method for regulating use of stored diluent in a polymerization process so as to maximize use of diluent recycled diluent recovered from the process, and so minimize use of stored diluent, is disclosed. Also disclosed is apparatus, particularly as an arrangement of controllers and valves for handling the flow of diluent through the process that can be used to implement the disclosed process.

Abstract: Systems and methods are provided for controlling chemical production and/or petroleum processing reaction systems to allow for improved control of control variables relative to desired set points. The improved control can be achieved by use of a modified proportional-integral-derivative (PID) controller or a similar type of controller that includes dynamic tuning logic. The modified PID controller can be operated using different coefficients based on the relative values of a control variable and a reasonable progress curve determined based on the values of the control variable.

Abstract: A process for maintaining an optimum polymerization process in a continuous loop polymerization reactor by driving a catalyst feed range set-point around a bad catalyst set-point range using a bad catalyst feed rate program to vary the catalyst feed rate for differing periods of time between previously determined good catalyst feed rates.

Abstract: A process and system for maintaining optimum polymerization production in a loop polymerization reactor by continuously and periodically obtaining polymerization results, such as melt index (MI), production rate and ash content of the polymer produced, determining whether each of the results is within desired ranges, storing and averaging recently obtained results in a database within a reaction rate controller program, and when one of the results is out of the desired range modifying at least one reaction parameter set-point such as monomer concentration, catalyst feed rate and reactor temperature to drive any out-of-range polymerization result(s) toward the desired range for that result.

Abstract: Systems and methods are provided for controlling chemical production and/or petroleum processing reaction systems to allow for improved control of control variables relative to desired set points. The improved control can be achieved by use of a modified proportional-integral-derivative (PID) controller or a similar type of controller that includes dynamic tuning logic. The modified PID controller can be operated using different coefficients based on the relative values of a control variable and a reasonable progress curve determined based on the values of the control variable.