ASTM D7994-17

5.1 The total fluorine, chlorine, and sulfur contained in LPG, similar low molecular weight hydrocarbons, and DME can be harmful to many catalytic chemical processes, lead to corrosion, and contribute to pollutant emissions. While LPG specifications limit sulfur, some specifications also contain precautionary statements about fluorine. Chlorine has been known to contaminate LPG with detrimental consequences. This test method can be used to determine total fluorine (as fluoride), chlorine (as chloride), and sulfur (as sulfate ion) in process streams, intermediate and finished LPG products, similar low molecular weight hydrocarbons, and DME (1.1).

1.1 This test method covers the individual determination of total fluorine, chlorine, and sulfur in liquid petroleum gas (LPG), low molecular weight hydrocarbons, their mixtures, and dimethyl ether (DME) in the range of 1 mg/kg to 300 mg/kg fluorine and sulfur and 5 mg/kg to 300 mg/kg for chlorine. This test method is applicable to products described in Specifications D1835 and D7901 and it can be applicable to process streams with similar properties to LPG and other materials such as butylene, propylene, and olefins.

1.2 This test method can also be applied to the measurement of the bromine and iodine in samples covered by the scope of this test method, but the precision and bias statement of this test method is not applicable to these halides.

1.3 This test method can be applied to sample concentrations outside the scope of this test method through adjustments of sample injection volume or number of injections combusted (or both), adjustment of injection volume to the ion chromatograph, and adjustment of the final dilution volume of the absorbing solution prior to injection to the ion chromatograph. The precision and scope of this test method is not applicable to samples that are outside the scope of the method.

1.4 The values stated in SI units are to be regarded as standard.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Section 9.

1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.