ASTM D7157 compliant automated fuels stability analyser

ROFA France automated fuels stability analyser applies a procedure for quantifying the intrinsic stability of asphaltenes in oil. The analyser conforms to the ASTM D7157 Test Method, the standard test method for measuring the intrinsic stability of asphaltenes in crude oils, residual products, and related materials.

The France automated fuels stability analyser is applicable to a wide range of products, including residual products from thermal and hydrocracking processes, products typical of ASTM D396 Grades 5L, 5H, and 6, and D2880 Grades 3-GT and 4-GT, and all types of crude oils. The instrument works on products containing a minimum of 0.2% concentration of asphaltenes.

The France automated fuels stability analyser quantifies asphaltenes stability in terms of the state of peptization of the asphaltenes (S-value), the intrinsic stability of the oily medium (So), and the solvency requirements of the peptised asphaltenes (Sa). The operating principle is based on titration and optical detection of precipitated asphaltenes.

Three different mixtures of the sample oil and aromatic solvent (toluene) are simultaneously and automatically titrated with paraffinic solvent (n-heptane) to cause precipitation of asphaltenes. An optical probe monitors the formation of flocculated asphaltenes during titration. The start of flocculation is determined when the optical probe detects a significant and sustained decrease in the rate-of-change of 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 the specimen, and the volume of toluene, for each determination.

The ROFA France automated fuels stability analyser is available from one to three test stations, working simultaneously according to customer needs. Each unit comes with one titration pump, one titration test position, one detection probe, Windows based proprietary software, and a PC.