Nonlinear Control Algorithm for Industrial Hot Water Corrosion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for controlling oxygen scavenger feed in industrial water systems are inadequate, as they rely on linear feed rates based on system flow rates, failing to address dynamic changes in corrosion potentials and DO variations, leading to unacceptably high DO levels and insufficient corrosion control.
Innovation Solution
A nonlinear control algorithm is implemented to adjust oxygen scavenger/reductant feed based on real-time oxidation-reduction potential (ORP) and system parameters, using a derived nonlinear equation that considers factors like DO, temperature, pH, and flow rates to maintain constant ORP and minimize corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If linear feed rate control based on system flow rates is used, then the control system is simple to operate, but it fails to address dynamic changes in corrosion potentials and DO variations, leading to insufficient corrosion control
Solution Approach 1:
The patent implements dynamic control by using a nonlinear algorithm that continuously adjusts oxygen scavenger feed rates based on real-time system parameters including flow rate, temperature, pressure, and dissolved oxygen levels. This replaces the static linear feed rate approach with a dynamic system that adapts to changing corrosion potentials and operational conditions, thereby improving corrosion control effectiveness while maintaining operational simplicity through automated control.
Solution Approach 2:
The control system incorporates feedback mechanisms by monitoring real-time measurements of dissolved oxygen levels, corrosion potentials, and system parameters. This feedback is fed into the nonlinear algorithm which then adjusts the oxygen scavenger feed rate accordingly. The closed-loop feedback control ensures that the system responds to actual corrosion conditions rather than relying on predetermined linear relationships, resolving the contradiction between operational simplicity and control effectiveness.
2Device complexity
If conventional linear feed control is used, then the device complexity is low, but high DO conditions can exist for long periods before corrective action is taken
Solution Approach 1:
The nonlinear control algorithm performs preliminary actions by continuously monitoring system parameters and predicting corrosion risks before they materialize. The system proactively adjusts oxygen scavenger feed rates based on trends in dissolved oxygen levels, temperature, pressure, and flow rate changes. This preliminary detection and response capability allows the system to correct DO variations before they lead to high corrosion potentials, improving reliability without significantly increasing device complexity.
Solution Approach 2:
The patent replaces simple mechanical feed control mechanisms with an intelligent software-based nonlinear algorithm. This substitution eliminates the need for complex mechanical adjustment devices while achieving superior response times. The algorithm processes multiple sensor inputs and dynamically calculates optimal feed rates, replacing manual or mechanical control systems with an automated computational approach that responds rapidly to changing conditions.
3Reliability
If residual scavenger concentration is maintained in boiler water, then corrosion protection is provided, but it does not ensure satisfactory treatment when low temperature or short residence time conditions exist
Solution Approach 1:
The nonlinear control algorithm dynamically adjusts oxygen scavenger feed rates based on real-time temperature and residence time parameters. When low temperature or short residence time conditions are detected, the algorithm increases the scavenger feed rate to compensate for reduced reaction efficiency. This parameter-based adaptation ensures that adequate corrosion protection is maintained across varying operational conditions, resolving the contradiction between providing corrosion protection and adapting to different temperature and residence time scenarios.
Solution Approach 2:
The system transitions from static residual concentration maintenance to dynamic feed rate adjustment based on actual process conditions. The nonlinear algorithm continuously monitors temperature and residence time parameters, adapting the oxygen scavenger dosage in real-time to match the changing kinetics of the scavenging reactions. This dynamic approach ensures effective corrosion protection whether the system operates at high temperature with long residence time or low temperature with short residence time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures stable ORP and reduced corrosion rates by actively responding to system stresses, providing a reliable method for maintaining low corrosion conditions in industrial water systems without direct ORP measurement.
Implementation Method 1
controlling the feed of oxygen scavengers, metal passivators, and other reductants/oxidants to industrial water systems to control the potential for corrosion
Implementation Method 2
mechanical deaeration, where the water is typically heated to above its boiling temperature in a vented vessel. The solubility of the DO in water decreases as the temperature increases
Data Source
AI summary
This invention provides a method of preventing corrosion in industrial water systems. The method includes maintaining a real-time oxidation-reduction potential at a set point, wherein the system is at operating temperature and pressure. A nonlinear equation is derived based upon theoretically derived or empirically collected data. The equation is then used to determine an inflow of active chemical species to the water system.