Biodiesel: role of standard Alternative Fuel Biodiesel: role of standard Caswell Hlongwane

WHAT IS BIODIESEL FUEL Def: ASTM D 6751 Fuel comprised of mono-alkyl esters of long chain fatty acids derived from vegetables or animal fats, designated B100

NOTATION Bxx: a blend of biodiesel with petroleum-based diesel fuel with xx representing volume percentage of biodiesel fuel

ALLOWED FEEDSTOCKS: vegetable oils Soybean oil Sunflower oil Canola oil Spent oil Biofuels Industrial Strategy of the Republic of South Africa, Dec 2007

HOW IS BIODIESEL FUEL PRODUCED

HOW IS BIODIESEL PRODUCED React three moles of vegetable oil with six moles methanol and one mole of potassium or sodium hydroxide Boil the mixture whiles stirring for 3hrs Wash biodiesel layer four times with water Recover unused methanol by simple distillation Purify biodiesel by vacuum distillation Store over magnesium sulfate Add antioxidants to improve oxidative stability of biodiesel

Regulated Specification IS BIODIESEL PRODUCED FIT TO BE BLENDED WITH DIESEL FUEL SANS 1935: 2004 Regulated Specification Petroleum Products Act (120/1977):Regulations: petroleum products specification and standards, gazetted June 23, 2006

Six general observations Twenty six test methods SANS 1935: requirements, total of 30 Six general observations Twenty six test methods

Methods only specific to biodiesel fuel, 14 BIODESEL FUEL TEST METHODS Methods only specific to biodiesel fuel, 14 Standard test method for each property Type of test Reasons why limits are set for each tested property

ESTER CONTENT Specification defines minimum mass percentage of 96.5% FAME Standard test method recommended by SANS 1935 is EN 14103 GC-FID test method

Why set minimum ester content for biodiesel Proving illegal admixture with other substances when neat In conjunction with EN 14078, one is able to determine tax allowance when blended with petroleum-based diesel fuel

FREE GLYCEROL SANS 1935 stipulates maximum value of 0.02% mass fraction of free glycerol in biodiesel Standard test method for determination of free glycerol is EN 14106 GC-FID test method

Why set a maximum limit for free glycerol in biodiesel fuel Free glycerol separates from biodiesel during storage and in fuel tanks Free glycerol attracts other polar compounds such as soaps, monoglycerides, etc., and causes damage to the fuel injection system Free glycerol corrodes metals in the fuel system Free glycerol is also know to clog the fuel filter

METHANOL CONTENT SANS 1935 limits methanol content to a maximum of 0.20% by mass Standard test method is EN 14110 GC-FID headspace test method

WHY LIMIT METHANOL IN BIODIESEL Low flash point of methanol poses safety risk during: Storage Transportation

Iodine Number and Linolenic acid methyl ester Iodine number is a measure of total unsaturation of biodiesel SANS 1935 limits total iodine number to a maximum of 120 gI2/100g biodiesel using EN 14111, a titration method SANS 1935 also limits linolenic acid methyl ester to a maximum 12 % by mass using EN 14103, GC-FID test method

Why Regulate the Degree of Unsaturation of FAME in Biodiesel Fuels with high iodine number polymerize at high temps and form deposits on Injector nozzles Piston ring grooves These polymers also reduce lubricity of FAME Highly unsaturated FAMEs have low oxidation stability leading to degradation products that lead to poor engine operability

ACID VALUE Measure of neutralization number of mineral acids and FFA in biodiesel SANS 1935 limits acid value of biodiesel to a maximum of 0.50 mg/g biodiesel Standard test method is EN 14104 Titration test method: KOH/EtOH, Phenolphthalein

ACID VALUE: why regulate Corrosion within the engine Deposits within the engine

PHOSPHORUS CONTENT Phosphorus in biodiesel comes from phospholipids contained in the feedstock

PHOSPHORUS CONTENT IN BIODIESEL SANS 1935 limits phosphorus in biodiesel fuel to a maximum of 10 ppm The standard test method recommended is EN 14107 ICP-OES

PHOSPHORUS IN BIODIESEL: why regulate Phosphorus decreases efficiency of oxidation catalytic converters Increased emission of particulate matter

Alkali metals end up in biodiesel during production Biodiesel Alkali & Alkali Earth Metal Content Alkali metals end up in biodiesel during production Alkali earth metals mostly originate from use of hard water during washing stage SANS 1935 limits alkali and alkali earth metals to a sum maximum of 5 ppm, respectively ICP-OES

Na and K form ash in the engine Why Limit Amounts of Group I and II Metals Na and K form ash in the engine Ca and Mg are responsible for getting the injector pump sticky

Problems that may arise with the use biodiesel fuel that does not meet SANS 1935 Tax evasion Damage to the fuel injection system Corrosion of metals in the fuel system Clogging of fuel filter Safety risks during storage and transportation Sticky injector pump Deposits on injector nozzles and piston ring grooves Poisoned oxidation catalytic convertor Increased emission of particulate matter Ash formation in the engine

SUMMARY: why do we need biodiesel fuel standard Guideline for production process Guarantee users a quality fuel Approved tool for assessment of safety risks and environmental pollution Offer engine and automobile manufactures assurances to release warranties for their vehicles to be operated on specific fuels

References Biodiesel: the comprehensive handbook, Martin Mittelbach and Claudia Remschmidt, 2004 Petrol and Diesel in South Africa, SAPIA, 2008 Significance of tests for petroleum products, Ed 7, Salvatore J Rand, 2003 The biodiesel handbook, Gehard Knothe, Jon van Gerpen, and Jurgen Krahl, 2005 SANS 1935:2004, Ed 1, Automotive biodiesel fuel, Standards South Africa Biofuels industrial strategy of the republic of South Africa, Department of Minerals and Energy, 2007 Petroleum Products Act (120/1977):Regulations: petroleum products specification and standards, gazetted June 23, 2006

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