Flame Ionization Detector Oxygen Cross-Sensitivity Compensation
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Solution Overview
Problem
Flame ionization detectors exhibit cross-sensitivity to oxygen, which is not effectively addressed by existing methods that require specific combustion gas mixtures or burner nozzles, or separate oxygen meters.
Innovation Solution
Compensating for oxygen cross-sensitivity by using the measured flame temperature to correct the ion current evaluation, allowing for stable operation with pure hydrogen as the combustion gas and no specialized burner nozzles, while maintaining constant gas inflows and correcting for ambient pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pure hydrogen is used as combustion gas, then operating cost is reduced, but cross-sensitivity to oxygen occurs
Solution Approach 1:
The patent replaces the mechanical/chemical solution (complex gas mixtures or specialized burner nozzles) with a thermal measurement and evaluation approach. By measuring flame temperature and using it in the evaluation of ion current, the system compensates for oxygen cross-sensitivity without requiring complex combustion gas mixtures or specialized burner hardware.
Solution Approach 2:
The patent changes the evaluation parameter by introducing flame temperature measurement and using it to correct the ion current evaluation. Instead of changing the combustion gas composition or burner structure, the system measures temperature and uses this parameter to compensate for oxygen interference in the hydrocarbon concentration calculation.
2Object-affected harmful factors
If hydrogen-helium or hydrogen-nitrogen mixture is used as combustion gas, then cross-sensitivity to oxygen is compensated, but operating cost increases
Solution Approach 1:
The patent uses a simple, inexpensive temperature sensor and standard evaluation electronics instead of expensive specialized gas mixtures. The temperature measurement approach provides a cost-effective solution that eliminates the need for continuous supply of expensive hydrogen-helium or hydrogen-nitrogen mixtures.
Solution Approach 2:
The patent changes from modifying the combustion gas composition (expensive approach) to measuring and utilizing flame temperature as a compensation parameter (cost-effective approach). This parameter change allows oxygen cross-sensitivity compensation without incurring the continuous cost of specialized gas mixtures.
3Measurement precision
If temperature measurement is used to compensate oxygen cross-sensitivity, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the temperature sensor serve multiple functions: it monitors flame stability and simultaneously provides data for compensating oxygen cross-sensitivity in hydrocarbon measurements. This multi-functionality approach improves measurement precision without proportionally increasing device complexity, as the same temperature measurement serves dual purposes.
Solution Approach 2:
The patent introduces flame temperature as an intermediary parameter that mediates between the ion current measurement and the final hydrocarbon concentration calculation. The temperature acts as a correction factor that accounts for oxygen interference, improving measurement precision while adding only a single temperature sensor and evaluation step.
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 eliminates the need for expensive gas mixtures and specialized burner designs, providing accurate hydrocarbon concentration measurements by accounting for oxygen content fluctuations in the sample gas, ensuring reliable operation and cost-effectiveness.
Implementation Method 1
the hydrocarbons contained in the sample gas are combusted in a burner in the presence of air and while supplying hydrogen
Implementation Method 2
carbon-containing molecules can be ionized in a gas flame and verified by measuring an electrical current
Implementation Method 3
a temperature sensor measuring the temperature of the gas flame, wherein the evaluation device is embodied, during the evaluation of the measured ion current, to compensate for the cross-sensitivity thereof to the oxygen in the sample gas using the measured temperature
Data Source
AI summary
A flame ionization detector includes a burner to combust an oxygen-containing sample gas in a gas flame in the presence of air and while supplying a hydrogen-containing combustion gas. A measurement device measures an ion current from the gas flame to an electrode, and a temperature sensor measures a temperature of the gas flame. An evaluation device evaluates the measured ion current and compensates during evaluation of the measured ion current for a cross-sensitivity of the ion current to oxygen in the sample gas using the measured temperature of the gas flame.