Title: Indirect measurement of diluents in a multi-component natural gas

Abstract

A method of indirectly measuring the diluent (nitrogen and carbon dioxide) concentrations in a natural gas mixture. The molecular weight of the gas is modeled as a function of the speed of sound in the gas, the diluent concentrations in the gas, and constant values, resulting in a model equation. A set of reference gas mixtures with known molecular weights and diluent concentrations is used to calculate the constant values. For the gas in question, if the speed of sound in the gas is measured at three states, the three resulting expressions of molecular weight can be solved for the nitrogen and carbon dioxide concentrations in the gas mixture.

Inventors:

Morrow, Thomas B.; Owen, Thomas E.

Issue Date:

2006-03-07

Research Org.:

Southwest Research Institute, San Antonio, TX (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1175665

Patent Number(s):

7010433

Application Number:

10/809,097

Assignee:

Southwest Research Institute

Patent Classifications (CPCs):

G - PHYSICS G01 - MEASURING G01N - INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES

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G - PHYSICS G01 - MEASURING G01N - INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES

G01N2291/0215 - Mixtures of three or more gases, e.g. air
G01N2291/02809 - Concentration of a compound, e.g. measured by a surface mass change
G01N2291/02881 - Temperature
G01N29/024 - by measuring propagation velocity or propagation time of acoustic waves
G01N29/323 - {compensating for pressure or tension variations}
G01N29/326 - {compensating for temperature variations}
G01N29/4418 - {with a model, e.g. best-fit, regression analysis}
G01N33/225 - {Gaseous fuels, e.g. natural gas}

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DOE Contract Number:  

FC21-96MC33033

Resource Type:

Patent

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY