Standard Test Method for Mercury Sampling and Analysis in Natural Gas and Other Gaseous Fuels by Amalgamation Atomic Fluorescence Spectroscopy

Importancia y uso:

5.1 This test method can be used to determine the total mercury concentration of natural gas and other sources of gaseous fuels (as defined by Terminology D4150) down to 0.001 μg m^-3. It can be used to assess compliance with environmental regulations, predict possible damage to gas plant equipment, and monitor the efficiency of mercury removal beds.

5.2 The preferred sampling method for mercury collection is on supported gold sorbent such as gold impregnated on silica, which allows the mercury to be trapped and extracted from the interfering matrix of the gas. Thermal desorption of mercury is performed by raising the temperature of the tube by means of a nichrome wire coiled around it.

5.3 Amalgamation AFS is a pre-concentration technique, and the working range of this method can be adapted by collecting different volumes of gas. Detection limits below 0.001 µg m^-3 can be achieved with large sample volumes (for example, >50 L) when low blanks are obtained. Using small sample volumes (for example, <1 L) the working range of the method can be extended to several thousand µg m^-3.

Subcomité:

D03.06.03

Volúmen:

05.06

Palabras clave:

atomic fluorescence spectroscopy; gaseous fuel; gold tube; mercury sampling; natural gas;