Process Heater Oxygen Discrepancy Detection

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Solution Overview

Problem

Inefficient and unsafe operation of combustion systems due to incorrect oxygen measurements caused by excess air, tramp air, or insufficient air, leading to imbalanced fuel-air ratios and potential safety hazards, as well as burner tip clogging resulting in inefficient heat distribution and safety concerns.

Innovation Solution

A system with intelligent monitoring and control, including a process controller that uses physics-based modeling to determine expected oxygen levels and identify airflow discrepancies, and a burner tip health indicator to monitor and maintain optimal burner performance, thereby adjusting air and fuel ratios and preventing tip plugging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If oxygen measurements are used to control fuel-air ratio, then combustion efficiency is improved, but measurement accuracy deteriorates due to excess air, tramp air, or insufficient air

Engineering Contradiction:

Improvecombustion efficiencyVSAvoidoxygen measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system introduces multiple intermediate sensors (exhaust gas oxygen sensor, combustion chamber oxygen sensor, and air inlet sensors) as mediators to indirectly measure and detect airflow discrepancies. These sensors act as intermediaries between the actual combustion process and the control system, providing accurate data about air-fuel ratio imbalances without being directly exposed to the harsh combustion environment that would compromise measurement accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements multiple feedback loops where oxygen measurements from different locations (exhaust gas, combustion chamber, air inlets) continuously feed back to the control system. This feedback mechanism allows the system to detect deviations from optimal air-fuel ratios and automatically adjust combustion parameters, maintaining both measurement accuracy and combustion efficiency through continuous correction.

Inventive Principle:

Principle #23Feedback

2Difficulty of detecting and measuring

If multiple sensors are deployed throughout the combustion system, then detection capability is improved, but system complexity increases

Engineering Contradiction:

Improveairflow discrepancy detection capabilityVSAvoidsensor system complexity

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The system segments the combustion process into distinct zones (air inlets, combustion chamber, exhaust gas path) and places sensors at each segment. This segmentation allows each sensor to measure specific local conditions independently, improving overall detection capability while organizing the complex sensor network into manageable, functionally-separated components that can be installed and maintained separately.

Inventive Principle:

Principle #1Segmentation

3Reliability

If burner tips are monitored for clogging, then safety is improved, but operational complexity increases due to frequent maintenance requirements

Engineering Contradiction:

Improveburner safetyVSAvoidmaintenance frequency

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system performs preliminary monitoring of burner tip conditions through oxygen measurements and combustion parameter analysis before actual clogging occurs. By detecting early signs of airflow discrepancies and combustion anomalies, the system can alert operators to potential tip clogging issues before they compromise safety, allowing for planned maintenance rather than emergency interventions.

Inventive Principle:

Principle #10Preliminary action

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

Ensures stable and efficient combustion processes by maintaining balanced air-fuel ratios and preventing burner tip fouling, enhancing safety and operational efficiency.

Implementation Method 1

an oxygen sensor positioned within the combustion chamber to measure an actual oxygen level

Methodology Applied

Scientific EffectOxygen sensing:

Implementation Method 2

a physics-based model of the combustion system is utilized to calculate an expected oxygen level

Methodology Applied

Scientific EffectCombustion chemistry calculation:

Data Source

PatentEP3830482B1Systems and methods for detecting discrepancy in a combustion system

Publication Date: 2022.08.17 ONPOINT TECHNOLOGIES LLC

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AI summary

Systems and methods for determining operating discrepancy a process heater. The discrepancy may be identified by solving a fired-systems model of the heater. The fired-systems model is then compared to current operating data. If the sensed current operating data is outside of the expected value(s), as defined by the fired-systems model, the systems and methods may take a remediation action to resolve the discrepancy. The discrepancy may include convection fouling identification and identification of tramp-air leaks within the process heater that are otherwise not easily detected by a human operator.