Case Study – Properties of Liquid Hydrocarbon Mixtures
The challenge
A technology company requires a software tool that will calculate the properties of
a mixture of liquid hydrocarbon compounds. The user must be able to select
individual components from a database and specify the amount of each component.
Then, at the click of a button, the software tool must be able to solve algebraic
equations that relate the properties of the mixture to the properties of the
individual components and the amount of each component.
The solution
Atkinson Science created a Windows application to meet the precise requirements of
the client. The user may specify the amount of each component by volume, volume
fraction or volume percentage. Some mixture properties are temperature-dependent,
so the user must enter the mixture temperature. The application calculates all of
the properties required by the client, including the kinematic viscosity, the
density, the freezing point, the flash point, the initial boiling point, the 10%,
50% and 90% distillation temperatures, and the final boiling point. The user can
save the mixture composition to a file that can be reloaded and the user can
export the calculated mixture properties to an Excel spreadsheet.
One of the most complex calculations is that of the kinematic viscosity, which is a
temperature-dependent property. This is calculated in the application by the
Wright blending method, which is an American national standard. A hand calculation
for a mixture consisting of 50% by volume of n-dodecane and 50% by volume of
methylcyclohexane at 15°C gives a kinematic viscosity of 1.409
mm2/s. In the figure below the same mixture composition has been
entered into the application and one can see that the mixture kinematic
viscosity at 15°C calculated by the application agrees with the hand
calculation.
The benefits
By incorporating complex physics into a Windows application, Atkinson Science were
able to fulfill all of the requirements of the technology company.