ASTM D7551-10(2015)

5.1 The sulfur content of gaseous hydrocarbons, LPG, and LNG used for fuel purposes contributes to total SOx emissions and can lead to corrosion in engine and exhaust systems. Some process catalysts used in petroleum and chemical refining can be poisoned by trace amounts of sulfur-bearing materials in the feed stocks. This test method can be used to determine the total volatile sulfur content in process feeds, to control the total volatile sulfur content in finished products and, as applicable, to meet regulatory requirements. Practice D1072 has previously been used for the measurement of total sulfur in gaseous fuels.

1.1 This test method covers the determination of total volatile sulfur in gaseous hydrocarbons, Liquefied Petroleum Gases (LPG) and Liquefied Natural Gas (LNG). It is applicable to analysis of natural gaseous fuels, process intermediates, final product hydrocarbons and generic gaseous fuels containing sulfur in the range of 1 to 200 mg/kg. Samples can also be tested at other total sulfur levels using either pre-concentration methods or sample dilution using a diluent gas. The methodology for preconcentration and dilution techniques is not covered in this test method. The precision statement does not apply if these techniques are used in conjunction with this test method. The diluent gas, such as UHP nitrogen, zero nitrogen or zero air, shall not have a significant total sulfur concentration.

1.2 This test method may not detect sulfur compounds that do not volatilize under the conditions of the test.

1.3 This test method covers the laboratory determination and the at-line/on-line determination of total volatile sulfur in gaseous fuels, LPG, and LNG.

1.4 This test method is applicable for total volatile sulfur determination in gaseous hydrocarbons, LPG, and LNG containing less than 0.35 mole % halogen(s).

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 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 Sections 4.1, 7.3, 7.4, 11.2, and Section 8.