Flare Combustion Control Using Ultrasonic Heating Value Measurement
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Solution Overview
Problem
Existing flare control systems face challenges in continuously measuring the heating value of flare gas due to the slow response time of gas chromatographs and calorimeters, which are not suitable for real-time adjustments in industrial plants with fluctuating gas compositions.
Innovation Solution
A flare combustion control system utilizing an ultrasonic measurement system to determine the sound speed of flare gases, allowing for continuous and accurate calculation of net heating value, and adjusting assist gas flow and tip velocity to maintain efficient and smokeless operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a gas chromatograph is used to determine flare gas composition and calculate BTU value, then the heating value can be determined through speciation, but the response time is slow (many minutes) and cannot keep up with fast fluctuations in flare gas composition
Solution Approach 1:
The patent replaces the mechanical gas chromatograph system with an acoustic measurement system that uses sound speed measurements to directly determine the heating value of flare gas. This substitution eliminates the slow speciation process and provides continuous, real-time measurements that can respond to fast fluctuations in gas composition.
Solution Approach 2:
The patent changes the measurement parameter from compositional speciation to sound speed measurement. By measuring the acoustic velocity of the gas and using it to calculate heating value, the system achieves both accuracy and fast response time, as sound speed measurements can be made continuously without the delays inherent in chromatographic analysis.
2Productivity
If a calorimeter is used to calculate BTU value of flare gas, then continuous heating value measurement is possible, but the response time is still greater than one minute and gas speciation cannot be performed
Solution Approach 1:
The patent replaces the calorimeter system with an acoustic measurement system. Instead of measuring heat release through combustion, the system measures sound speed through the gas, which provides both faster response time (continuous measurement) and the additional capability to determine gas composition through speciation algorithms.
Solution Approach 2:
The acoustic measurement system serves multiple functions: it continuously measures heating value, determines gas composition through speciation, and provides real-time data for control adjustments. This multi-functionality eliminates the need for separate GC and calorimeter systems while providing superior performance in both response time and measurement capability.
3Measurement precision
If gas chromatograph and calorimeter are used separately, then both speciation and heating value measurement can be achieved, but the system complexity increases and neither provides real-time continuous measurement
Solution Approach 1:
The patent merges the functions of gas chromatograph (speciation) and calorimeter (heating value measurement) into a single acoustic measurement system. By measuring sound speed and using computational algorithms, the system simultaneously determines both gas composition and heating value, eliminating the need for multiple separate instruments and reducing overall system complexity.
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
Enables real-time optimization of flare operations by providing accurate and repeatable flow measurements, maintaining minimum net heating value, and ensuring compliance with environmental regulations by reducing visible emissions and optimizing combustion efficiency.
Implementation Method 1
an ultrasonic measurement system for determining a sound speed of the flare gases
Data Source
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AI summary
A system for flare combustion control includes a sound speed measurement device for measuring sound speed in a flare vent gas, and a flare combustion controller including a memory and a processor. The processor is configured to receive the measured sound speed and determine, based on the measured sound speed, a molecular weight of the flare vent gas. The processor is further configured to determine, based on the determined molecular weight, a net heating value of the flare vent gas, and adjust the net heating value of the flare vent gas by regulating an amount of a supplemental fuel gas in the flare vent gas.