Infineum publishes winter diesel fuel quality survey results for Southern Hemisphere

Infineum has published the results for the Southern Hemisphere data set from its biannual Winter Diesel Fuel Quality Survey, which includes analysis of samples collected at service stations in Argentina, Australia, Brazil, Chile, Colombia, New Zealand, Peru and South Africa.

The samples were carefully selected to represent the production from each refinery or region in the eight countries, with the data providing insight into some of the most pressing topics in the diesel industry. These topics include the use of renewable fuels, the decrease in fuel sulphur levels, and the trends in oxidation and cloud point.

Mixed picture for Fatty Acid Methyl Ester (FAME)

In Australasia, the only current mandate for the use of FAME for biodiesel is in New South Wales at a ratio of 2%. However, the latest survey identified evidence of a sample containing 4% in Australia, just as was found in Infineum’s 2012 survey. While biodiesel is sometimes blended at a ratio of 5%-20%, currently the only mandate for biodiesel use is in New South Wales at 2%.

This may not represent the real situation of FAME use in Australia however, because most of the diesel fuel is sold in bulk to commercial customers, which is outside the scope of the survey.

Although no FAME samples were found in New Zealand, this could change in future surveys as Z Energy’s 20 million litre/annum biodiesel plant comes online. While biodiesel is neither mandatory nor subsidised in New Zealand, Z Energy says its B5 drop-in biodiesel blend will be available in certain regions towards the middle of 2016.

Levels of FAME ranged in Latin America from Chile, the only country in the region sampled with no mandated blending levels in place, to 11% in Argentina. This spread of results is unsurprising considering local mandates govern FAME use and these vary considerably from country to country.

For example, in Brazil, the government set a 7% blending ratio in 2014 and the biodiesel industry is advocating a B10 blend by 2020 as the industrial capacity is more than twice the actual production target and raw materials available. Meanwhile, Argentina and Colombia already have 10% biodiesel blending ratios and in Peru the current mandate is B5.

Sulphur levels continue downward trend

With the exception of one sample from Brazil and one from South Africa, sulphur levels in the Southern Hemisphere have continued to fall over the past two years. This may be due to the influence of sample collection since rural diesel tends to have higher sulphur levels than city diesel.

In Argentina, average sulphur levels have fallen 73% since 2012 and it is the only country sampled that still has an average sulphur level in the hundreds, rather than tens, of ppm.

Argentina has achieved a 49% decrease in its average sulphur level from 2014, but we might expect the sulphur cuts scheduled in June 2016 to mean results from our 2018 survey will show an average figure more in line with other Latin American countries.

Lower cloud point

As a whole, the cloud point (CP) of the Southern Hemisphere samples appears to be lower in 2016 compared to 2004. Over the 2014-2016 period, South Africa and Peru have continued this trend, while the reverse has been evidenced in Argentina and Brazil.

The causes of this movement in cloud point are likely to include, but may not be limited to:

1. The need to reduce back-end distillation to facilitate sulphur reduction
2. Increased use of imported diesel in some locations
3. Specification changes
4. Sampling variation
5. Seasonal formulation differences

Regardless of the cause, refiners have managed to maintain consistent fuel quality with all fuels remaining on specification.

Oxidation stability falling

This year’s survey highlights a significant deterioration in oxidation stability in the samples from Argentina and Brazil, with a reasonable percentage of samples from Peru found to have a Rancimat of less than 20 hours.

The cause of this is unclear, although it could be attributed to poor FAME quality or to a lack of antioxidant additive use. In certain circumstances, poor oxidation stability can lead to higher levels of particulate matter in fuels, which has the potential to cause filterability issues and may result in fuel starvation and engine operating difficulties.

On examining the filterability results of two samples from Argentina with Rancimat of less than 10 hours, both failed to meet filterability targets.

By-products of oxidation may be contributory factors in fuel filterability performance and in reducing vehicle filter longevity. However, several other factors need to be considered when analysing field issues related to filter blocking.

Looking ahead

As fuels become more complex and the global demand for diesel continues to increase, it is essential to monitor the quality of a wider portfolio of diesel fuels to ensure they meet the specific requirements of each market and each application.

The full data set from the 2016 Winter Diesel Fuel Quality Survey will include data on the quality of marine bunker fuels sampled in European Emission Control Areas for the first time. The results will be available in October.

To read the full Infineum Winter Diesel Fuel Quality Survey Southern Hemisphere results, visit: http://www.infineuminsight.com/insight/mar-2016/diesel-quality-update