Abstract
The importance of correct determination of physical and chemical properties of natural gas is evident.
The calculation of calorific value or hydrocarbon dew point requires detailed analysis as can be provided by gas chromatography. Analysis by gas chromatography is a necessary complement to direct measurement of physical properties. An accurate gas chromatographic analysis allows the calculation of various gas properties at the same time. Several schemes allowing accurate
natural gas analysis by chromatography have been described in literature.
Current column selection criteria to meet the requirements of a particular gas analysis will be presented. In the presentation the main emphasis will be on new developments in column technology for gas chromatography. Recent developments in capillary gas chromatography point in three directions:
1. Narrow bore thin film columns (typically 50 ~m inside diameter; 0.05 ~m film thickness) allowing a high speed of separation and having large plate numbers per unit length.
These columns having up to 1 million theoretical plates are eminently suited for a detailed analysis of the distribution of higher hydrocarbons in natural gas e.g. for dew point calculations.
2. Wide bore thick film columns. These columns with typical dimensions of 0.5 mm inside diameter and a film thickness of 5-10 ~m of 'bonded phases', are relatively slow but offer improved resolution for the low boiling point components of natural gas. The sample capacity of a wide bore thick film column is at least two orders of magnitude larger than that of 50 ~m
columns. This together with the large volumetric gas flows in wide bore columns enables their use in combination with heat conductivity detectors or FT-IR techniques.
3. The use of gas-solid chromatography in open tubular columns e.i. Molsieve 5 A PLOT columns for the analysis of permanent gases at ambient temperature; Aluminium oxide columns for highly selective separations of volatile hydrocarbons.
A theoretical treatment will be presented showing the effect of column diameter and film thickness on speed of analysis, resolution, sample capacity, sample range, etc. The instrumental requirements of the different types of columns will be discussed. Examples on applications in natural gas analysis will be given.
| Original language | English |
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| Title of host publication | Gas Quality : Proceedings of the Congress of "Gas Quality - Specification and Measurement of Physical and Chemical Properties of Natural Gas", Groningen, the Netherlands, 22-25 April 1986 |
| Editors | G.J. Rossum, van |
| Place of Publication | Amsterdam |
| Publisher | Elsevier |
| Pages | 443-457 |
| ISBN (Print) | 0-444-42628-0 |
| Publication status | Published - 1986 |
| Event | conference; Congress of "Gas Quality - Specification and Measurement of Physical and Chemical Properties of Natural Gas" ; (Groningen, Netherlands) : 1986.04.22-25 - Duration: 1 Jan 1986 → … |
Conference
| Conference | conference; Congress of "Gas Quality - Specification and Measurement of Physical and Chemical Properties of Natural Gas" ; (Groningen, Netherlands) : 1986.04.22-25 |
|---|---|
| Period | 1/01/86 → … |
| Other | Congress of "Gas Quality - Specification and Measurement of Physical and Chemical Properties of Natural Gas" ; (Groningen, Netherlands) : 1986.04.22-25 |