Economics-based coordination of advanced process control and real-time optimization

A method for control and optimization of a process, comprising:

• receiving process data and economic data corresponding to the process to be controlled;
• calculating an economic objective function based on the process data, the economic data and a nonlinear steady-state model of the process;
• deriving a non-linear approximation of the economic objective function in terms of a set of process control variables associated with the process;
• transmitting the non-linear approximation to an advanced process control module;
• and
• controlling the process according to the non-linear approximation and within a constraint to drive the process toward a constrained economic optimum by the advanced process control module;
• wherein the non-linear approximation is comprised of a Hessian matrix and a gradient vector which represent an economic surface in terms of the set of process control variables of the process.

A method for control and optimization of a process, comprising:

• receiving process data and economic data corresponding to the process to be controlled;
• calculating an economic objective function based on the process data, the economic data and a nonlinear steady-state model of the process;
• deriving a non-linear approximation of the economic objective function in terms of a set of process control variables associated with the process;
• transmitting the non-linear approximation to an advanced process control module;
• and
• controlling the process according to the non-linear approximation and within a constraint to drive the process toward a constrained economic optimum by the advanced process control module;
• wherein the non-linear approximation of the economic objective function is a local quadratic approximation of the economic objective function.

A system for coordinating advanced process control and real-time optimization of a process, comprising:

• a real-time optimization (RTO) module for calculating an economic objective function based on process data, economic data and a nonlinear steady-state model of the process and deriving a non-linear approximation of the economic objective function in terms of a set of process control variables of the process;
• and
• an advanced process control (APC) module for controlling the process according to the non-linear approximation and within a constraint to drive the process toward the economic objective;
• wherein the RTO module operates at a lower frequency than the APC module.

An article of manufacture comprising a machine readable medium having stored instructions that, when executed by a computer system:

• receive process data and economic data corresponding to the process to be controlled;
• calculate an economic objective function by a real-time optimization module based on the process data, the economic data and a nonlinear steady-state model of the process;
• derive a non-linear approximation of the economic objective function by the real-time optimization module in terms of a set of process control variables associated with the process;
• transmit the non-linear approximation to an advanced process control module;
• and
• control the process according to the non-linear approximation and within a constraint to drive the process toward the economic objective by the advanced process control module;
• wherein the non-linear approximation of the economic objective function is a local quadratic approximation of the economic objective function.