ASTM D2784 Test Method for Sulfur in Liquefied Petroleum Gases (Oxy-Hydrogen Burner or Lamp)
3. Summary of Test Method
3.1 The sample is burned in an oxy-hydrogen burner, or in a lamp in a closed system in a carbon dioxide-oxygen atmosphere. The latter is not recommended for trace quantities of sulfur due to the inordinately long combustion times needed. The oxides of sulfur are absorbed and oxidized to sulfuric acid in a hydrogen peroxide solution. The sulfate ions are then determined by either of the following finishes:
3.1.1 Barium Perchlorate Titration - The sulfate is titrated with barium perchlorate using a thorin-methylene blue mixed indicator.
3.1.2 Turbidimetric - The sulfate is precipitated as barium sulfate and the turbidity of a suspension of the precipitate is measured with a photometer.
4. Significance and Use
4.1 It is important to have the sulfur content of liquefied petroleum gases at low enough concentration to meet government regulations. The presence of sulfur can result in corrosion of metal surfaces. Sulfur can be poisonous to catalysts in subsequent processing.
