Natural Gas Analysis Using Polarized Raman Spectroscopy.

Raman spectroscopy is a promising tool for measuring the composition of natural gas. However, to obtain high measurement accuracy, it is necessary to take into account changes in the spectral characteristics of methane, since its spectrum overlaps the characteristic bands of other species. In this study we present a technique for natural gas analysis based on polarized Raman spectroscopy.

Raman Natural Gas Analyzer: Effects of Composition on Measurement Precision.

Raman spectroscopy is a promising method for analyzing natural gas due to its high measurement speed and the potential to monitor all molecular components simultaneously. This paper discusses the features of measurements of samples whose composition varies over a wide range (0.005-100%).

Application of Raman Spectroscopy for Determination of Syngas Composition.

Raman spectroscopy is a unique tool for fast analysis of multicomponent gas media. In this work, we studied the features of application of this method for monitoring the syngas (mixture of CO + H + CH + CO + N) composition. To determine concentrations, we used contour fit method, where the Raman spectrum of mixture is compared with a synthetically calculated spectrum.

Collection optics for a Raman spectrometer based on the 90° geometry of scattered light collection.

In the present work, efficiency of classical lens, mirror-lens, and pure mirror variants of the collection optics for a Raman spectrometer based on 90° geometry of scattered light collection is investigated. It is experimentally established that, despite a smaller collection angle, in the case of a relatively narrow input slit of the spectrometer (<100  μm), the lens optics with corrected off-axis and chromatic aberrations allows larger signal intensities to be registered. However, the low f/# mirror collection optics described in the work provide a more stable adjustment and can be used to increase the Raman signal intensities in cases when the image of the scattering volume formed by them is commensurable with the sizes of the input slit of the spectrometer.

Raman Gas Analyzer (RGA): Natural Gas Measurements.

In the present work, an improved model of the Raman gas analyzer (RGA) of natural gas (NG) developed by us is described together with its operating principle. The sensitivity has been improved and the number of measurable gases has been expanded. Results of its approbation on a real NG sample are presented for different measurement times.