Blend (mineral oil)

Mixed mineral oil products such as diesel fuel , heating oil (EL and S) and petrol are also known as blends . These products are mixed together from different components, whereby the qualities of the components - u. a. due to the crude oil selection - can vary greatly. As a specification-compliant product must be manufactured, the composition is modified in such a way that the specifications are met.

The blend can be calculated in advance, whereby there must be a functional relationship between the quality of the components (e.g. RON ) and the quality of the product (e.g. Eurosuper with Spec: RON> 95) - depending on the mixing ratio. Usually there is a linear relationship (e.g. - trivially - for density , benzene content ). Qualities that show a non-linear behavior can often be linearized by introducing an index function ( bijective function of quality). Furthermore, a distinction must be made as to whether the quality blends in proportion to the volume (“linear on volume”, LOV) or proportionately to weight (“linear on weight”, LOW). Due to the possibly large number of specifications, a system results with a number of linear inequalities that can be solved together with the mass and volume conservation equations and a suitable objective function with the help of linear programming . The blending margin is often used as a target function . The solution is the mixing ratio and the resulting blend qualities, all of which should then be within the specifications. Mixtures in the mineral oil industry, which are based on fixed mixing ratios, are not referred to as a blend, but rather as a recipe.

The following table shows the most important qualities of various fuels and heating fuels as well as the methods of calculating the blend from the component qualities.

		unit	LOV	LOW	index	Remarks
Motor gasoline
	density	kg / L	x
	DVPE (RVP)	kPa	x		= DVPE 1.25	Chevron index
	Olefin content	% vol	x
	Benzene content	% vol	x
	Aromatic content	% vol	x
	Sulfur content	mg / kg		x
	Oxygen content	% mass		x
	E70	% vol	x			1)
	E100	% vol	x			1)
	E150	% vol	x
	End of boiling	° C				3)
	Vapor Lock Index	(dimensionless)				3), but can be calculated from the result
	RON	(dimensionless)	x			1)
	MOZ	(dimensionless)	x			1)
Diesel / heating oil  EL
	density	kg / L	x
	calorific value	MJ / kg		x
	Calorific value	MJ / kg		x
	Cloud point	° C	x		only with index	2)
	Cold filter plugging point	° C	x		only with index	2)
	Sulfur content	mg / kg		x
	viscosity	mm² / s		x	only with index	2)
	E250	% vol	x
	E350	% vol	x
	E360	% vol	x			to specify the 95% point
	Flash point	° C	x		only with index	2)
	Cetane number	(dimensionless)	x
	Cetane index	(dimensionless)				3)
	Poly aromatics	% mass		x
Marine fuel oils , heavy fuel oil
	density	kg / L	x
	calorific value	MJ / kg		x
	Pour point	° C	x		only with index	2)
	CCT ( MCR )	% mass		x
	Sulfur content	% mass		x
	Flash point	° C	x		only with index	2)
	Metals etc.	mg / kg		x
	viscosity	mm² / s		x	= 14.534 + ln (ln (v + 0.8)) + 10.975	1) 4)

¹⁾ Proprietary indices are also often used

²⁾ Proprietary indices are used

³⁾ Glare calculation not possible

⁴⁾ Viscosities of all components must have been determined at the same temperature.

Individual evidence

1. ↑ Example of a MoGas blend (PDF; 17 kB) - exercise uni-koeln.de.
2. ↑ Example of a fuel oil blend .
3. ↑ Chevron Blending Index ( Memento of August 24, 2010 in the Internet Archive ) (PDF; 543 kB)
4. ↑ Viscosity blend in the English language Wikipedia