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The Metrohm 852 dual KF analyser means low level moisture in finished biodiesel and higher levels in raw materials can be measured very simply on the same instrument.
As of the 15th April 2008, all petrol and diesel which is sold at UK pumps now has to include at least 2.5% biofuels The obligation extended to 3.25% biofuels content in 2009. The idea behind the Renewable Transport Fuels Obligation (RTFO) is to reduce climate change emissions from transport - which produced more than a quarter of overall greenhouse gases in the UK - by using renewable fuels instead of fossil fuels. These renewable fuels have been added to fuel sold around the country.
Biodiesel is obtained from vegetable oils (e.g. rapeseed, soybean and jatropha oil)
by esterification with methanol. Biodiesel is a mixture of fatty acid methyl esters (FAME).
Minimum requirements exist for the quality of biodiesel; these were defined in 2003 by the European Standard DIN EN 14214.
The amount of water in biodiesel determines the calorific value and, above all, the
shelf life of the fuel. Biodiesel with a high water content has a clearly lower oxidation
stability. The lower the oxidation stability, the greater the probability that oxidation
products will be formed during long storage periods. These can cause engine
problems due to deposits, particularly with the injection system. In order to avoid
this, DIN EN 14214 limits the maximum water content to 500 ppm.
The ISO standard 12937 «Petroleum products – Determination of water – Coulometric
Karl Fischer titration method» describes the Karl Fischer coulometric titration
for determining the water content. The range of KF Coulometers from Metrohm
easily meet all the specifications demanded by the standard and are outstandingly
suitable for this application. In most cases the sample can be injected directly into
the reaction solution with a syringe. In order to improve the solubility of the samples,
xylene (dimethyl benzene) is added to the KF reagent. Annex B of the standard
also describes the volumetric determination.
The advantages of the 852 dual KF system from Metrohm means that one instrument can be used for low level moisture determination finished products via the KF Coulometer cell (1 ppm to 0.1%) and the volumetric KF cell can be used for quick checks and in oils and raw materials with suspected higher levels of moisture (>0.1%).
Please contact Metrohm UK for further information and to arrange a demonstration. Tel 01928579600 or Email enquiry@metrohm.co.uk
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