Real-Time Flare Control Using Tunable Infrared Gas Analysis
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Solution Overview
Problem
Current flare control systems are unable to efficiently manage the combustion of vent gases due to slow compositional analysis, leading to inefficient combustion and potential environmental non-compliance during rapid changes in vent gas composition, particularly during emergency shutdowns or sudden operational changes.
Innovation Solution
A real-time flare control method and apparatus that utilizes an online tunable infrared absorption based gas analyzer to measure hydrocarbon concentrations in the vent gas stream, allowing for immediate adjustment of steam or air flow, and optionally supplemental fuel gas, to maintain efficient combustion across a wide range of operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gas chromatography is used to measure vent gas composition, then measurement precision is achieved, but measurement speed is too slow to respond to rapid changes in vent gas composition
Solution Approach 1:
The patent replaces the mechanical gas chromatography system with an optical absorption system (tunable diode laser or infrared spectrometer) that measures hydrocarbon concentrations through light absorption. This substitution enables real-time measurement at 10-100 Hz while maintaining measurement precision, directly resolving the contradiction between measurement accuracy and speed.
2Reliability
If steam or air flow is increased to maintain combustion efficiency, then combustion efficiency improves, but energy loss increases due to wasted steam
Solution Approach 1:
The patent implements a feedback control system where real-time hydrocarbon concentration measurements are continuously fed back to the control algorithm, which dynamically adjusts steam or air flow rates. This closed-loop feedback enables precise matching of oxidizer supply to actual combustion needs, maintaining 96.5%+ combustion efficiency while minimizing steam waste by eliminating excessive flow.
Solution Approach 2:
The control system dynamically adjusts steam or air flow rates in real-time based on changing vent gas composition and flow conditions. This dynamic adaptation allows the system to optimize combustion efficiency across varying operating conditions without wasting steam during low-flow periods or insufficiently combusting during high-flow periods.
3Reliability
If supplemental fuel gas is added to increase combustion zone temperature, then combustion efficiency improves, but substance loss increases due to unnecessary fuel consumption
Solution Approach 1:
The feedback control system uses real-time hydrocarbon concentration measurements to determine the exact amount of supplemental fuel gas needed to maintain combustion efficiency. This precise feedback control eliminates unnecessary fuel addition while ensuring adequate combustion zone temperature and efficiency, directly reducing substance loss.
Solution Approach 2:
The system dynamically changes the supplemental fuel gas flow parameter based on real-time measurements of vent gas composition, flow rate, and combustion zone temperature. This parameter adjustment ensures fuel is added only when necessary to maintain efficiency, minimizing substance loss while meeting combustion requirements.
4Adaptability or versatility
If manual control is used to adjust steam or air flow, then adaptability to changing conditions is achieved, but productivity decreases due to slow response time
Solution Approach 1:
The patent implements an automated self-service control system that continuously measures hydrocarbon concentrations and automatically adjusts steam or air flow without human intervention. This self-service automation maintains high adaptability to changing vent gas conditions while dramatically improving productivity by eliminating the slow response inherent in manual control operations.
Solution Approach 2:
The automated feedback control system continuously monitors hydrocarbon concentrations and immediately adjusts oxidizer flow in response to changing conditions, providing both the adaptability of manual control and the high productivity of automation. The system responds within seconds rather than minutes or hours, resolving the contradiction between adaptability and productivity.
5Adaptability or versatility
If the flare system is designed to handle the full range of vent gas flow rates, then adaptability improves, but device complexity increases
Solution Approach 1:
The patent employs dynamic control algorithms that adapt to varying operating conditions rather than requiring a statically oversized system. The control system dynamically adjusts oxidizer flow and supplemental fuel based on real-time measurements, enabling a single flare system to efficiently handle the full range of vent gas flow rates from low to high without requiring multiple specialized systems or excessive capacity.
Solution Approach 2:
The control system changes multiple parameters (steam/air flow rate, supplemental fuel gas flow, oxidizer to fuel ratio) dynamically based on operating conditions. This multi-parameter adjustment allows the flare system to maintain optimal performance across a wide range of vent gas flow rates without increasing physical system complexity, as the same hardware operates under different controlled parameters.
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 efficient combustion of vent gases with a combustion efficiency of at least 96.5% and environmental compliance by enabling rapid adjustments to steam or air flow based on real-time analysis, thereby improving operational efficiency and reducing emissions.
Implementation Method 1
an online tunable infrared absorption based gas analyzer to measure hydrocarbon concentrations in the vent gas stream
Implementation Method 2
supplying air or steam to the combustion zone of the flare along with a supplemental fuel gas as necessary
Data Source
AI summary
Disclosed herein are embodiments of a flare control method and a flare apparatus for automatically controlling, in real-time, the flow of one or more of fuel, steam, and air to a flare. The disclosed embodiments advantageously allow for automated control over a wide spectrum of operating conditions, including emergency operations, and planned operations such as startup and shutdown.