SIST-TP CEN/TR 16435:2013

SIST-TP CEN/TR 16435:2013 is the Slovenian adoption of CEN/TR 16435:2012, a CEN Technical Report on oxygenates blending in liquid petroleum products. It gives guidance to blenders on how oxygenates and alcohols affect petrol composition so they can stay within the legal limits linked to the revised Fuels Quality Directive and the EN 228 unleaded petrol requirements.

What does SIST-TP CEN/TR 16435:2013 specify?

SIST-TP CEN/TR 16435:2013 provides background information for blending oxygenates and alcohols into unleaded petrol. The document is organized into a foreword, Scope, Background, General issues, Reference data, Blend examples, and a Bibliography.

The report focuses on practical blending questions: which oxygenates are covered by EN 228, how oxygen content relates to blend composition, and how mass fraction and volume fraction should be interpreted in this context. For readers, that means the document is mainly a guide for formulation and checking, not a general petrol specification.

What are the key requirements of SIST-TP CEN/TR 16435:2013?

SIST-TP CEN/TR 16435:2013 is guidance rather than a requirements standard, but it gives several practical rules and reference points for blend design.

Clause 2 - use EN 228:2012 as the main limit reference

Clause 2 ties the report to EN 228:2012, especially the lists of allowed oxygenates and oxygen content in Tables 1 and 2 of that standard. In practice, a blender uses this report together with EN 228 to check whether a planned blend stays inside the allowed petrol limits.

Clause 3 - convert % (m/m) and % (V/V) with care

Clause 3 explains that the link between % (m/m) and % (V/V) depends on density and on non-linear blending effects such as volume change. It also notes that density changes with composition and temperature. For the reader, this means a simple fixed conversion is not reliable unless the component properties and measurement conditions are well defined.

Clause 4 - use the selected property data as reference values

Clause 4 gives selected properties for petrol and common oxygenates, including density, molecular weight, and oxygen content. The table covers methanol, ethanol, isopropyl alcohol, tertiary butyl alcohol, isobutyl alcohol, MTBE, ETBE, TAME, and TAEE. In practice, these values help compare blend options and estimate how much oxygen each component contributes.

Clause 5 - the worked blend examples are deliberately constrained

Clause 5 provides six blend examples based on fixed assumptions: petrol density of 750 kg/m3, no more than two oxygenates in a blend, ethanol as the only alcohol considered, and ETBE as the only ether considered in the examples. The examples are built around E5 and E10 cases and show how oxygen content changes for ethanol-only, ETBE-only, and mixed blends.

Clause 5 - use the equations when density is known

Clause 5 also gives equations for converting between mass fraction and volume fraction when the density of the finished blend and the oxygenate are known. In practice, this is the calculation step a blender uses to move between lab reporting, blending targets, and tank farm measurements.

Clause 2 and Clause 4 - remember the data are based on pure products

The report states that the reference data are based on pure chemical products. If impurities, by-products, or unreacted feedstocks are present, the values may shift slightly. That matters because commercial oxygenates may not behave exactly like the reference materials.

What terms does SIST-TP CEN/TR 16435:2013 define?

• oxygenate - An oxygen-containing blending component used in petrol to adjust oxygen content.
• mass fraction, μ - The share of a component expressed as % (m/m).
• volume fraction, φ - The share of a component expressed as % (V/V).
• EN 228 - The petrol standard this report uses as the main limit reference for unleaded petrol.
• EtOH - Ethanol, one of the alcohol oxygenates listed in the property table.
• ETBE - Ethyl tertiary butyl ether, one of the ether oxygenates used in the blend examples.
• E5 and E10 - The two petrol blend cases used in the examples to show how oxygen content changes with different oxygenate mixes.

Who uses SIST-TP CEN/TR 16435:2013?

SIST-TP CEN/TR 16435:2013 is for people who formulate, handle, or check petrol blends containing oxygenates. That includes fuel blenders, refinery and terminal operators, and quality personnel who need to compare planned blends with EN 228 limits. It is also useful for laboratories and technical staff who measure density or oxygen content and need to interpret results in blending terms.

What changed in SIST-TP CEN/TR 16435:2013 from the previous edition?

SIST-TP CEN/TR 16435:2013 is the Slovenian adoption of CEN/TR 16435:2012.

Which standards are used with SIST-TP CEN/TR 16435:2013?

The report is linked to EN 228:2012, Automotive fuels - Unleaded petrol - Requirements and test methods. EN 228:2012 provides the petrol requirements and the oxygenate and oxygen-content limits that this Technical Report uses as its main reference point.

What does the SIST-TP CEN/TR 16435:2013 document contain?

The document contains a short background discussion, selected property data for petrol and common oxygenates, and six worked blend examples. Table 1 gives density, molecular weight, and oxygen content for the listed components. Table 2 shows example E5 and E10 oxygenate blends, including ethanol-only, ETBE-only, and mixed cases.

It also includes two equations for converting between mass fraction and volume fraction when densities are known. Those calculations are the core tool for translating blend targets into practical formulation checks. The bibliography points to EU fuel directives, EN 228:2012, and technical sources used for the property data.