Application
The Wobbe Index (WI) expresses the heating value (known as calorific value) of gases used as fuels, taking into account the proportionality of calorific value to the specific gravity, or the density ratio between the given fuel gas and air. More precisely, the specific gravity is proportional to flow velocity through a constant orifice size at a constant pressure, and thus proportional to gas calorific value.

This measurement is important to operators because it can quickly determine the interchangeability of two or more fuel gas streams. At a flare or a custody transfer station, this measurement is a constant necessity.

Principle of OperationTo analyze the chemical composition of the sample, the OMA performs infrared spectroscopy using an InGaAs (indium gallium arsenide) sensor. The system measures absorbance from 1550 to 1850nm and quantifies the amount of light absorbed by the sample; the OMA plots this raw data to visualize a high-resolution absorbance spectrum.
The OMA uses a long-life tungsten light source to transmit a signal through the sample fluid in the flow cell. The signal is carried by fiber optic cables from the analyzer to the flow cell, where the chemical mixture of the sample has unique interactions with the light based on its current composition

Documentation

Wobbe Index Analyzer