Measurement of hydrocarbon fuel gas composition and properties from tunable diode laser absorption spectrometry
US10495570B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 2016 |
| Grant date | Dec 3, 2019 |
| Priority date | — |
| Expiry date | Oct 3, 2036 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/129
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A tunable diode laser absorption spectrometer and a method of processing absorption spectra is used to measure concentrations of selected fuel gas components and calculate several fuel gas parameters, including heating value, relative density, compressibility, theoretical hydrocarbon liquid content and Wobbe index. In the described incarnation, a tunable laser diode directs near-infrared light into an optical cavity through a sample of fuel gas. A sensor measures intensity of light exiting the cavity as the laser wavelength is tuned over a specified range to construct a cavity-enhanced absorption spectrum for the fuel gas. A set of basis spectra for expected component species is used to analyze the spectrum and determine component concentrations, including methane, ethane, carbon dioxide, and other discrete and structured absorbers. Critically, a generic broadband absorption is used to model higher hydrocarbons that present themselves as nearly featureless absorption spectra. The fuel gas parameters are then calculated directly from determined component concentrations and the broadband absorption representing the higher hydrocarbons.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.