Nitrogen Measurement via Ammonia Transformation and IR Detection

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Solution Overview

Problem

Current methods for determining the nitrogen concentration in natural gas are costly and lack direct sensing capabilities, hindering efficient and widespread monitoring of diluent gas components in the gas industry, particularly for compliance with regulatory standards and accurate custody transfer pricing.

Innovation Solution

A two-step method involving chemical reforming or direct excitation-dissociation-formation processes to transform nitrogen into detectable compounds like ammonia, using nonthermal plasma discharges and nondispersive infrared detection for quantitative measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If gas chromatograph is used to measure nitrogen concentration, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvenitrogen concentration measurementVSAvoidmeasurement system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical gas chromatograph system with an optical detection system. Specifically, it uses infrared absorption spectroscopy where nitrogen is transformed into ammonia which is then detected by an infrared sensor. This substitution of mechanical separation and detection with optical methods simplifies the overall system while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces ammonia as an intermediary substance to enable nitrogen detection. Since nitrogen itself is not directly detectable by infrared methods, it is chemically transformed into ammonia through catalytic reaction or plasma processes. This intermediary allows the use of simpler infrared detection technology while indirectly measuring nitrogen concentration with high precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If gas chromatograph is used for nitrogen measurement, then measurement accuracy is improved, but ease of operation deteriorates

Engineering Contradiction:

Improvenitrogen concentration measurementVSAvoidmonitoring operation

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The complex operational procedures of gas chromatography (sample injection, column separation, detector calibration) are replaced by a continuous flow infrared absorption system. The transformed ammonia passes directly through the infrared cell for real-time measurement, eliminating the need for complex operational steps while maintaining accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables continuous monitoring of nitrogen concentration through continuous transformation and detection. Unlike gas chromatography which requires discrete sample analysis, the infrared system provides uninterrupted real-time measurements, significantly improving ease of operation for ongoing gas composition monitoring.

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If inferential method is used to determine gas energy content, then productivity is improved, but measurement precision of nitrogen deteriorates

Engineering Contradiction:

Improvegas energy determination speedVSAvoidmolecular nitrogen concentration

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent uses ammonia as a detectable intermediary that maintains a direct quantitative relationship with nitrogen concentration. This allows for direct measurement rather than inferential calculation, providing both the speed of direct detection and the precision of nitrogen-specific measurement through the established stoichiometric relationship in the transformation reaction.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 near-real-time, accurate, and cost-effective determination of nitrogen concentration in natural gas, facilitating efficient monitoring and compliance with regulatory standards, and supporting widespread implementation in the gas industry.

Implementation Method 1

chemical reforming or direct excitation-dissociation-formation processes to transform nitrogen into detectable compounds like ammonia

Methodology Applied

Scientific EffectChemical reforming: Chemical Bonding

Implementation Method 2

using nonthermal plasma discharges and nondispersive infrared detection for quantitative measurement

Methodology Applied

Scientific EffectNonthermal plasma discharges: Plasma

Implementation Method 3

nondispersive infrared detection for quantitative measurement

Methodology Applied

Scientific EffectNondispersive infrared detection: Absorption (EM radiation)

Data Source

PatentUS7781220B2Measurement of nitrogen content in a gas mixture by transforming the nitrogen into a substance detectable with nondispersive infrared detection

Publication Date: 2010.08.24 SOUTHWEST RES INST

AI summary

A method of determining the amount of nitrogen in a gas mixture. The constituent gases of the mixture are dissociated and transformed to create a substance that may measured using nondispersive infrared adsorption techniques.