Dynamic Optimization of Industrial Processes via Linearization

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Solution Overview

Problem

Existing industrial processes face challenges in optimizing both measured and unmeasured process variables to minimize objective functions subject to constraints, particularly in non-linear dynamic systems where steady-state conditions are not consistently maintained.

Innovation Solution

A method and system that utilize Wiener-Hammerstein block-oriented nonlinear models to relate state vector values over time, allowing for the minimization of steady-state objective functions by linearizing memory-less nonlinearities and solving the problem as a sequence of linear static optimization problems, even during transients, using linear programming techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If non-linear dynamic optimization is applied to industrial processes, then optimization accuracy is improved, but computational complexity increases

Engineering Contradiction:
Improveoptimization accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the non-linear dynamic optimization problem into multiple linear sub-problems by dividing the time horizon into discrete intervals and linearizing the system dynamics within each interval. This allows the complex non-linear problem to be solved as a sequence of simpler linear programming problems, reducing computational complexity while maintaining optimization accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary linearization step that transforms the non-linear system into a linear approximation. By using linearization techniques as an intermediary, the complex non-linear optimization is converted into a manageable linear programming problem that can be solved efficiently while still capturing the essential dynamics of the original system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If dynamic optimization during transients is implemented, then process control flexibility is improved, but mathematical model complexity increases

Engineering Contradiction:
Improveprocess control flexibilityVSAvoidmathematical model complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by formulating the optimization to handle time-varying conditions and transient states. The model incorporates dynamic behavior through time-dependent constraints and objective functions, allowing the system to adapt to changing conditions while using linear programming techniques to manage the mathematical complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes parameters by transforming the non-linear dynamic problem into a linear programming problem with time-varying parameters. By allowing parameters to change with time and using linearization, the system achieves flexibility in handling transient conditions without requiring complex non-linear mathematical models.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If both measured and unmeasured process variables are optimized, then comprehensive process optimization is improved, but data reconciliation difficulty increases

Engineering Contradiction:
Improvecomprehensive process optimizationVSAvoiddata reconciliation difficulty
Core Design Contradiction:
Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies universality by creating a unified linear programming framework that simultaneously handles both measured and unmeasured process variables. The model integrates data reconciliation and optimization into a single multi-functional system, allowing comprehensive process optimization while managing data reconciliation through consistent linear mathematical relationships.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS8271104B2Method and system for dynamic optimisation of industrial processes
Publication Date: 2012.09.18 ASPENTECH CORPORATION
  • US8271104B2 patent drawing
  • US8271104B2 patent drawing
  • US8271104B2 patent drawing

AI summary

Enables minimization of steady-state objective function P(z∞), subject to a set of constraints zmin≦z∞≦zmax, and under the assumption that the values of the state vector, z, at different points in time related via a model expressed in dynamic open equation format Q(z∞, zk, zk-1, zk-2, . . . , zk-n)=0, where z∞ is predicted final value of state vector, z, and zk, zk-1, zk-2, . . . , zk-n are current and previous values of state vector, z. Determines optimum operation of an industrial process having steady-state objective function P(z∞), including: receiving outputs from the process; minimizing steady-state objective function P(z∞) subject to set of constraints zmin≦z∞≦zmax; wherein values of state vector at different times are related via model of form Q(z∞, zk, zk-1, zk-2, . . . , zk-n)=0; to minimize objective function P(z∞). Industrial process to be optimised may include measured and unmeasured process variables.