Oil Analysis in VMGSim
In this communication, we present the new Oil Analysis unit operation available in VMGSim 10.0. This unit operation produces Crude Oil analyses, similar to those reported in analytical laboratories, for any attached Material Stream that contains hydrocarbons. It also reports physical properties of the whole hydrocarbon stream and its fractions.
Oil Analysis Unit Operation
The Oil Analysis unit operation is a powerful tool that allows the estimation of physical properties and curves for crude oils and their cuts. The crude oil must be defined in the In port of the unit operation or in a Material Stream attached to the In port.
VMGSim provides default cuts for crude oils that can be customized in the Summary tab of this unit operation. For the first cut, the initial temperature is the Initial Boiling Point (IBP) of the crude oil. The End Temperature of the last Cut will be automatically set to the End Boiling Point (EBP) of the crude oil.
It is important to note that the cut names and end temperatures defined in this tab are global to the thermodynamic case, meaning that the same cuts are used if two or more Oil Analysis are added to a property package. These cuts are also shared with the Product Distribution cuts from the Distillation Curve unit operation.
The default cuts are:
- Lights: IBP – 31.1 °F (nC4 boiling point)
- Straight Run Naphtha: 31.1 – 200 °F
- Naphtha: 200 – 380 °F
- Kerosene: 380 -545 °F
- Diesel: 545 – 670 °F
- GasOil: 670 – 950 °F
- Resid: 950 °F – FBP
The values of the physical properties of the crude and its cuts can be found in the Oil Analysis tab, this tab contains a table that captures all the physical properties and curves that have been calculated for the whole crude and its fractions. The reported properties and curves can be customized in the Settings tab.
The Oil Analysis table is reported in a similar fashion as most of the laboratory crude oil analysis, the columns represent the crude oil and its cuts whereas the rows are the physical properties and curves.
There are two types of Settings: one for the Distillation Curves and one for other physical properties.
Distillation Curve Settings
In this tab, the distillation curves to be shown in the oil analysis can be selected. This tab also allows the user to select the Basis (Mass, Mole, Volume) and Conversion Method of the selected distillation curve as well as, to specify the number of points and distillation percents to be calculated for the curve. The list of available Distillation curves includes:
Here the desired properties to be shown in the oil analysis can be selected. The list of properties includes:
Once a physical property from the previous list has been selected other configurations can be enabled:
The number of Cn+ Fractions to be calculated can be customized as well as their basis.
The desired Refinery properties to be shown in the analysis can be selected, the list includes:
The Component Contents and its basis (Mass or Mole) to be shown in the analysis can be selected here, the list includes:
Density, Viscosity and Kin. Viscosity Curves
The number of points and the temperatures at which these physical properties will be calculated can be customized, the properties are calculated at the requested temperature and 1 atm.
The tab named Plots contains curve plots and physical properties histograms based on the calculated values from the Oil Analysis tab.
This unit operation also contains a tab with a window that enlist any problem found during the calculation of the physical properties of the Oil Analysis; common errors include:
- Cuts that are too narrow or include less than 4 components, in this case distillation curves cannot be calculated
- Properties calculated for some cuts that are outside the validity range of the estimation method
- Empty cuts
- Properties requested for cuts outside the range of the property definition, for instance requesting Octane or Cetane number for heavy cuts
Herbert Loria, Ph.D, P.Eng., VMG Calgary
Please contact your local VMG office for more information.