Challenges of Biofuels testing

19/2/2007

Today and the future…

Over the years the petroleum industry has faced many challenges in terms of supply of crude and major changes in legal requirements to meet new mandated future fuel specifications. However the many industry bodies and government bodies globally are firmly predicting that conventional oil refined products will continue to form the major global source for the next 30 years.

Demand for global automotive fuels is continually increasing as developing nations increase wealth and growth of their economies with the resultant increase in aspirations for use of the motorcar. This is illustrated by China where there were just 1 million cars in 1990, by 2004 that number had increased twelve times. In 2005, in just one year, an additional 2.4 million new cars were added to the roads of China.

In Europe, and the US there has been increasing pressure in the last decade to try and improve the quality of air. This requirement has led to a significant improvement in auto vehicle engine development which, along with improved fuels, is aimed at reducing emissions such as CO2, SOx and NOx.

In the late 1980’s and ‘90’s, the European Auto Oil I and II programmes were developed. The recommendations were carefully considered and resulted in the legislative mandates which are in place in Europe today. These include the removal of lead based gasolines and new lower sulfur fuels (less than 10ppm). In the US, around the same time, California and the US EPA, started to significantly review and apply greater mandated requirements for fuel composition to ensure there was less than 15 ppm “zero” sulfur content. These new specifications have also been adopted by many other nations globally, in some cases they have been applied in geographical areas such as cities or large urban conurbations.

The push by governments, such as the US and Europe, to move to alternative sustainable fuels is now gathering at a significant pace. This is largely driven by the three main factors; employment, reduced dependence on crude oil (a diminishing resource), and finally perceived environmental benefits in terms of manufacture and emissions of the fuel combusted. In 2003, the European Commission introduced directive 2003/30/CE to promote the use of renewable fuels as a replacement for diesel and gasoline in transportation. The key objective is to increase the Biofuels resource pool from a value of 2% in 2005 to a minimum of 5.75% by 2010.

The term Biofuels encompasses a diverse range of products such as biogas and biodiesel (which consists of methyl esters of vegetable oils such as rapeseed, coconut, palm & soyabean oils). For blended diesel fuels (B5) there is primarily the Fatty Acid Methyl Ester (FAME) material and Fatty Acid Ethyl Ester (FAEE) material which is currently under development and evaluation. This will conclude in the revision of the EN 14214 specification to allow both FAME and FAEE to be referenced in the future European diesel extender specification.

In the case of gasolines the main extender is bio ethanol along with other bio alcohols such as methanol and biobutanol.

The current EN 590 standard for automotive diesel allows up to 5% biodiesel to be added to diesel fuel. However, to meet the new 5.75% target a new mandate is being prepared to revise EN 590 to allow up to 10% biodiesel extender to be used.

There are a number of advantages of Biofuels such as; reduced emissions, no aromatics, possible lubricity benefits, ability to be blended with conventional fuels and less toxicity. However, there are issues around the levels of ash content produced on combustion containing elements such as; silicon, sodium, phosphorous and potassium which can cause significant wear problems to the engine. Also, some bio extenders can have higher Acid Numbers which may cause engine corrosion problems to metal surfaces and bearings.


Due to these concerns, and to enable industry to control the quality of these new bio materials, the Comité Européen de Normalisation (CEN) Technical Committee 19 has a special analytical Working Group 27 which is developing new test methods to cover a number of key elements to enable bio materials to be manufactured and tested so that they will not cause significant issues of fuel stability, engine operability and maintenance.

There is strong commitment from the auto industry to use Biofuels on the understanding that the bio components must fall within the fuel regulations to enable vehicle conformance to certified performance. To ease concerns the biofuels industry will to have ensure quality control and measurement of Bio alcohols to avoid metal corrosion from water and acid corrosion due to weak and strong acids and inorganic chlorides. Also of importance are the limits set on phosphorous content (less than 5 mg/L in ethanol) to prevent engine catalyst deterioration, copper content (less than 0.1 mg/kg), and sulfur content (less than 10mg/kg).

Concerns for biodiesel extender centre around the phosphorous content (less than 5 mg/L) and alkaline earth metals (Na, K, Ca & Mg at levels lower than 5 mg/kg). At higher levels these can potentially poison the engine/vehicle catalyst system thus affecting the performance of the vehicle and its ability to meet emission requirements. Experience shows that the presence of these elements at higher levels can also cause injector deposits and compromise fuel efficiency and combustion.