Product listing

S-Value

by ROFA

Standards

  • ASTM
    • D7157

Countries

  • Worldwide

Why has the measurement of fuels stability test become so important but complex at the same time?

Simple And Fast Explanation

What Type Of Products Are Covered?

Originally the products were mainly those from refining units, for the control of production units. Now all the fuels, crudes oils of all kinds, marine fuels and other new products, can be tested and analyzed with S-Value unit. The lower limit of 0.2% of asphaltenes mass is considered as the lower limit of detection for the type of measurement.

Market Application

Relevant oil cuts: Diesel / Domestic Fuels / Marine Fuels / Heavy Fuels Crudes Oil: 636 different types of Crudes Oils inventoried Control of Thermal Cracking unit (basic application), Visbreaker Products, Hydrocracking product H-Oi

What Does The Term “stability Of Fuels” Mean?

Fuels are composed of many constituents, some of which, like asphaltenes, can, depending on the conditions to which they are subjected, to go from a liquid state to a state, called «granular».
The reasons for the transition from the liquid state to the granular state are very numerous, complex, and sometimes difficult to identify.

What Happens In Case Of Instability?

This formation of granular deposits is called «flocculation» or «peptization». This formationcan appears depending on environmental conditions and more frequently when mixing two or more fuels together.
When this flocculation or peptization occurs, this means that the limit threshold stability of the fuel or the mixture of fuels, is reached. When the threshold of instability is reached or exceeded, particles in the form of granular deposits, will be generated in more or less important volume, depending on the nature and the mass of asphaltenes present in the fuel.
The other components, according to their own nature, such as maltenes or sulfur, can either contribute to flocculation or increase the speed of formation. The action or impact of these components is unpredictable.

What Are The Consequences?

The consequences are many. They can affect the pumping of fuels, their transport, their mixture, but the most serious problem occurs when using fuel oils as combustible.
It often happens that boats remain blocked due to the impossibility of pumping the fuel because of a very high flocculation density due to unexpected flocculation.
Examples could multiply. It is therefore sufficient to mention, to understand the importance of the problem, the figures of a 2014 report that estimated tens of billions of dollars per year, the cost of
uncontrolledand uncontrolled fuel stability.

S-Value technology is in constant evolution, with the permanent changes of the fuels present on the market. The analyser is supplied ready for use, with easy and fast installation. Very low maintenance is required to run the unit. On line support is available
all the year, and every day.

Example of results screen with all the different important information concerning the test.

S, Sa and So, are expressed in a small way for simplification of the understanding.

With the 3 results regression line is generated, with least square. Regression on 3 results guarantee that all the 3 results are good and coherent.

Correlation factor R² must be always above 0.98, to confirm the quality of the tests and the regression.
R²= Coefficient of determination

For standard stability test there are 3 different ranges of products:

  • Crude Oils
  • Marine Fuels
  • Distillates

Calculator will determines “Stability Prediction”: GOOD, POOR or BAD.
Stability factor” allows user to see where his fuels are located in the range of stability.

wish to see how to install and handle our revolutionary S-Value?

download our information video here.