DIN Standards Committee Materials Testing
DIN 51894
Gas analysis - Gas chromatographic method for fuel gases/natural gas and other gas mixtures
Gasanalyse - Gaschromatographisches Verfahren für Brenngase/ Erdgas und andere Gasgemische
Overview
This document has been prepared by NA 062-05-73 AA "Gasanalyse und Gasbeschaffenheit" ("Gas analysis and gas quality") of the Material Testing Standards Committee (NMP). This document specifies a gas chromatographic method for quantitative determination of the content of the following components with helium as the carrier gas. - nitrogen; - oxygen + argon; - carbon monoxide; - carbon dioxide; - methane; - ethene; - propene; - butane; - 2-methylpropane; - pentane; - 2-methylbutane; - 2,2-dimethylpropane - hexane. In addition, hydrogen (H2) and helium (He) contents can also be determined, if necessary. This requires that argon be used instead of helium as the carrier gas. In this case not the sum peak for oxygen + argon (O2 + Ar) is detected but only one peak for oxygen (O2). However, when argon is used as the carrier gas, then the detection sensitivity of the TCD is considerably reduced. Components that have not been eluted by the Porapak R column within the designated time of analysis can be back-flushed if required. They are quantified as a sum peak by the TCD. The method can be utilized for determination in online processes and in the laboratory. It is applicable for determining the components listed above in all technically feasible combinations in gas mixtures. The limiting factor is the hydrocarbon condensation point of the mixture; the gaseous mixture to be analysed shall not contain condensates. The precision of determination is primarily dependent on the separation of the individual components, the limits of determination at specific separation columns/detector combination as well as on the calibration. Detailed descriptions of measurement programmes and data evaluation procedures have been omitted in this document. For this purpose the specifications in DIN 51899 are applicable. The measurement programmes and data evaluation procedures for higher order calibration gas derivatives (reference standards of gas composition) are defined in DIN EN ISO 6143. DIN EN ISO 6143 is the basis for accreditation concerning such matters.
