New silicon and bio-diesel standards approved


A new standard has been approved for detecting silicon in gasoline and other fuel products.

Solid silcon

Silicon in solid form

The American Society for Testing and Materials (ASTM) International Committe D02 on Petroleum Products and Lubricants has given its seal of approval on ASTM D7757 and No. 1-B Grade.

The new standards cover testing to determine the total silicon content in gasoline, ethanol fuel blends and other fuel products and a voluntary standard for bio-diesel production.

ASTM D7757 will help remove silicon from fuels, the harmful element that can lead to the fouling of key engine components relating to the combustion process - such as spark plugs and oxygen sensors.

The standard relates to testing using monochromatic, wavelength-dispersive X-ray fluorescence spectrometry over a range of concentrations from three to 100mg/kg.  The test method itself was developed by ASTM's sub-commitee, D02.03 on Elemental Analysis, and has already been successfully adopted by fuel blenders even before the standard became official.

Silicon can lead to expensive maintenance and replacement costs and sub-committee Chairman, Kishore Nadkarni, heralded the new standard as a major step forward for the industry, adding that: "Any level of silicon in fuel gasoline is unacceptable since combustion results in silica deposits on the oxygen sensor in the engine exhaust, which can lead to a breakdown in the closed loop electrical feedback to the engine electronic control unit".

Meanwhile the testing authority also announced a new voluntary standard, ASTM D6751 No. 1-B Grade for bio-diesel production.  While the current standard will remain unchanged, but now entitled No. 2-B Grade, the new amendment is a voluntary addition which offers more stringent controls on some components used in the production of bio-diesel, such as vegetable oils and animal fats.  The new standard is set to help the limited number of filter-clogging cases discovered in Ultra Low Sulphur bio-diesel fuels.