ASTM D7621 Standard Test Method for Determination of Hydrogen Sulfide in Fuel Oils by Rapid Liquid Phase Extraction
1. Scope
1.1 This test method covers procedures (A and B) for the determination of the hydrogen sulfide (H2S) content of fuel oils such as marine residual fuels and blend stocks, with viscosity up to 3000 mm2s(-1) at 50 °C, and marine distillate fuels, as measured in the liquid phase.
NOTE 1 - Specification fuels falling within the scope of this test method are: ASTM Specification D396, MIL-DTL-16884, and ISO 8217.
1.2 Procedure A has been shown to eliminate interferences such as thiols (mercaptans) and alkyl sulfides. Procedure B can give elevated results if such interferences are present (see Annex A2).
NOTE 2 - A procedure for measuring the amount of hydrogen sulfide in crude oil can be found in Appendix X1. Full precision for Appendix X1 has not yet been determined.
1.3 Valid ranges for the precision are given in Table 2 and Table 3. Measurements can be made outside these ranges however precision has not been determined.
1.4 Samples containing FAME do not affect the measurement of hydrogen sulfide by this test method.
1.5 The values stated in SI units are to be regarded as standard. Non-SI units given in parentheses are for information only.
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.
2. Referenced Documents
2.1 ASTM Standards:
D396 Specification for Fuel Oils
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D5705 Test Method for Measurement of Hydrogen Sulfide in the Vapor Phase Above Residual Fuel Oils
D6021 Test Method for Measurement of Total Hydrogen Sulfide in Residual Fuels by Multiple Headspace Extraction and Sulfur Specific Detection
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
2.2 ASTM Adjuncts:
ADJ6300 D2PP Determination of Precision and Bias data for Use in Test Methods for Petroleum Products
2.3 ISO Standards:
ISO 4259 Petroleum Products - Determination and Application of Precision Data in Relation to Methods of Test
ISO 8217 Fuels (Class F) Specification of Marine Fuels
2.4 Energy Institute Standards:
IP 399 Test Method for Determination of Hydrogen Sulfide in Fuel Oils
IP 570 Test Method for Determination of Hydrogen Sulfide in Fuel Oils - Rapid Liquid Phase Extraction Method
2.5 U.S. Department of Defense Specifications:
MIL-DTL-16884 Fuel, Naval Distillate
3. Terminology
3.1 Definitions:
3.1.1 dead crude oil, n - crude oil with sufficiently low vapor pressure that, when exposed to normal atmospheric pressure at room temperature, does not result in boiling of the sample.
3.1.1.1 Discussion - The term "stabilized crude oil" is frequently used for a dead crude oil that has been produced by "flashing off" (distilling) light components from a live crude oil.
3.1.2 residual fuel oil, n - fuel oil comprising a blend of viscous long, short or cracked residue from a petroleum refining process and lighter distillates (blend stocks) blended to a fuel oil viscosity specification, burned for the generation of heat in a furnace or firebox or for the generation of power in an engine.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 liquid phase extraction, n - technique to determine the concentration of H2S gas trapped in a liquid by continuous analysis of gases extracted by bubbling air through the test specimen.
3.2.2 vapor phase processor, n - apparatus enabling low temperature removal of interfering vapors.
3.2.2.1 Discussion - The vapor phase processor holds a specific filter cartridge at -20 °C during the Procedure A test.
