Automatic analyzer for fuels stability determination according ASTM D 7157
S-Value Presentation – Test Method: ASTM D7157
Asphaltene Stability – Automated Instrument (Peptizing Power)
- Model SVA-42 Automated Fuels Stability Analyzer applies a procedure for quantifying the intrinsic
stability of the asphaltenes in an oil. A sample dissolved in toluene is titrated at room temperature with
n-heptane until an optical device detects asphaltine precipitation. The analyzer conforms to ASTM
D7157 Test Method.
- Model SVA-42 is applicable to residual products from thermal and hydrocracking processes, to products
typical of ASTM D396 Grades 5L, 5H, and 6, and D2880 Grades 3-GT and 4-GT, and to all types
ofcrude oils. The instrument is limited to products containing a minimum of 0.2% concentration of
- This analyzer quantifies asphaltene stability in terms of state of peptization of the asphaltenes (S-value),
intrinsic stability of the oily medium (So) and the solvency requirements of the peptized asphaltenes
- The operating principal of Model SVA-42 is based on titration and optical detection of precipitated
asphaltenes. Three different mixtures of the sample oil plus aromatic solvent (toluene) are
simultaneously and automatically titrated with paraffinic solvent (n-heptane) to cause precipitation of
- An optical probe monitors the formation of flocculated asphaltenes during the titration. The optical probe
consists of a system of light emitting and light receiving components. Flocculated asphaltenes alter the
detected light intensity. New model of Probe SVA-130 allows running fuels with very low mass of
asphatenes and very clear samples.
- The start of flocculation is interpreted when the optical probe detects a significant and sustained
decrease in rate-of-change of the light intensity.
- The results of the three flocculation determinations are used to calculate stability parameters and
subsequently the intrinsic stability of the oil from the added n-heptane at the inversion point, the mass of
specimen and the volume of toluene, for each determination
Model SVA-42 is supplied with 1 titration pumps, 1 titration test positions, 1 detection probes of each
model, Windows 7 based proprietary software, and a PC. On this unit can be connected 2 more tests
positions (code SAV-50) then can run 3 tests positions simultaneously.
Automated Determination of the Intrinsic Stability of Asphaltenes
Containing Residues, Heavy Fuel Oils and Crude Oils
• Conforms to ASTM D7157 Test Method
• Test Performed at Ambient Temperature
• Rapid Results (15 to 30 minutes)
• Up to Three Simultaneous Measurements
• Reduced Operator Errors
• Operator Time Saving
• Windows 7 Based Software
• Quick Investment Play-back
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