HYDROGEN SULFIDE IN RESIDUAL FUEL OILS: ASTM D5705
EXPLANATION
See the discussion under Test Method ASTM D6021. This test method covers the field determination of hydrogen sulfide in the vapor phase of a residual fuel oil sample. It is applicable to liquids with a viscosity range of 5.5 cSt at 40° C to 50 cSt at 100° C. The applicable range of hydrogen sulfide concentration is from 5 to 4000 ppm v/v.
TEST SUMMARY
A 1-L glass test bottle is filled to 50 volume % with fuel oil just prior to testing. In the test container, the vapor space above the fuel oil sample is purged with nitrogen to displace air. The test container with sample is heated in an oven at 60° C, and agitated on an orbital shaker at 220 r/min for 3 min. A length-of-stain detector tube and hand-operated pump are used to measure hydrogen sulfide concentration in the vapor phase of the test container.
Typically sulfur dioxide and mercaptans may cause positive interferences. In some cases, nitrogen dioxide can cause a negative interference. Most detector tubes will have a precleanse layer designed to remove certain interferences up to some maximum interferant level.
TEST PRECISION
Repeatability: 0.20X + 10
Reproducibility: 0.30X + 15
Where X is the average of the two results.
Bias of this test method has not been determined.
