TOTAL VOLATILE SULFUR IN GASEOUS HYDROCARBONS AND LPG USING COMBUSTION UV FLUORESCENCE DETECTION: ASTM D6667
EXPLANATION
The sulfur content of LPG, used for fuel purposes, contributes to 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 sulfur bearing materials in the feed stocks. This test method can be used to measure sulfur in process feeds, finished products, and can also be used for compliance determinations when acceptable to a regulatory agency. This test method is applicable to analysis of natural, processed, and final product materials (gaseous hydrocarbons and LPG) containing sulfur in the range 1 to 100 mg/kg. This test method may not detect sulfur compounds that do not vaporize under the test conditions. This test method is applicable for total volatile sulfur determination in LPG containing less than 0.35 m/m % halogen(s).
TEST SUMMARY
A heated sample valve is used to inject gaseous samples. LPG samples are injected by a sample valve connected to a heated expansion chamber. The gaseous sample then enters a high temperature combustion tube where sulfur is oxidized to SO2 in an oxygen rich atmosphere. Water produced during the sample combustion is removed, and the sample combustion gases are next exposed to ultraviolet light. The SO2 absorbs the energy from the UV light and is converted to an excited SO2. Fluorescence emitted from the excited SO2 as it returns to a stable state SO2 is detected by a photomultiplier tube. The resulting signal is a measure of the sulfur contained in the sample.
TEST PRECISION
Repeatability: 0.1152 (X)
Reproducibility: 0.3130 (X)
Where X is the average of two test results.
The bias of this test method was within the repeatability of this test method.
