Groot
A2OC Donor
Hi there.
Came across this rather one-sided but interesting article in The Telegraph at the weekend:
http://www.telegraph.co.uk/motoring/main.jhtml?xml=/motoring/2007/04/21/nosplit/mfbio21.xml
What's in your tank?
Are biofuels really a wonderful means of saving the planet, or is there a conspiracy of silence about the risks they pose? Peter Barlow reports
Some motorists get a warm feeling buying petrol or diesel with a biofuel component. After all, by reducing the consumption of crude oil and instead using fuel derived from renewable plants, which when burned releases only as much carbon dioxide as was absorbed by the growing crop, they are helping to save the planet from climate change, aren't they?
Take biodiesel, for example. Pure 100 per cent biodiesel (or B100) reduces new emissions of carbon dioxide (CO2) by some 60-80 per cent, so even a five per cent blend in conventional diesel (B5) will save up to four per cent on new CO2 emissions.
Biodiesel also has a higher cetane number, so there is less combustion knock and quieter engines, while its fatty properties provide good lubricity, giving lower fuel pump and injector wear. The natural products already contain some oxygen to provide lean burn with reduced hydrocarbon, carbon monoxide and particulate emissions. Add in the benefits to rural economies of growing the rape seed feedstock plus reduced oil imports and there are many purported benefits from adding biofuel components to conventional fuels.
Oil companies are progressively increasing the amount of B5 in UK diesel fuel in response to the Government's Renewable Transport Fuels Obligation, but what are the drawbacks? Unfortunately there are quite a few and the lack of information about them is beginning to resemble something of a conspiracy.
Natural fats are too viscous to be used in high-performance, low-emission diesel engines, so, via a process known as transesterification, the natural fat is changed using methyl alcohol and a catalyst into the Fatty Acid Methyl Ester (FAME). Most people concerned about their cardiovascular health will scan the nutrition boxes on packaged foods for fat content and the balance between saturated and monounsaturated and polyunsaturated fat. Unsaturated good! Saturated bad! Is it the same for fats in fuels? Well, yes and no. Highly saturated beef fat, or palm oil, crystalises at a higher temperature than the more unsaturated rapeseed oil or fish oil and as a result is more likely to cause winter waxing in diesel fuel.
Unsaturated fats in the body are more reactive and can be metabolised more easily. That is good. In biodiesel the methyl esters of the same unsaturated fat are also more reactive, but this makes them unstable to heat and oxygen, which is decidedly bad news. The chemistry of FAME increases its affinity with water, its conductivity, its reactivity and its bioavailability. For good measure, methyl esters are known degreasing solvents. They lift accumulated resins, gums, polymeric material, fuel additives and debris from storage tank walls and distribution pipework and carry them forward to block filters, or more worryingly, to pass through them. These may be filters on dispensers at service stations or fuel filters protecting your engine.
Being biodegradable might be good for the environment if there is a fuel spillage, but microbiological attack in storage tanks is not. Like humans, microbes need food and water. They live in the water and eat the fuel to grow. As they multiply they produce acid waste, which can corrode and perforate steel tanks. They form mats of slime that clog filters and plug fuel lines. To cap it all, microbial growth in biodiesel occurs at up to four times the rate in conventional diesel and is very expensive to expel. To date there have been outbreaks of microbiological infestations in biodiesel tanks in the North West, North East and South East.
The higher solubility of water in biodiesel can, under the right conditions, also trigger hydrolysis - decomposition by reaction with water. The reaction (Fatty) Acid + (Methyl) Alcohol = (Methyl) Ester + Water is reversible, so water plus diesel esters can produce methyl alcohol plus fatty acids. The acids released cause corrosion. This raises the issue of materials compatibility. Are all the materials - metals, alloys, polymers and plastics - in the present distribution system and retailing system compatible with biodiesel and its degradation products? The simple answer is no, they are not.
Consequently, with biodiesel there are increased risk factors and associated costs, and the greater the methyl ester concentration, the higher the risk. So B10 is more risky than B5, which is more risky than B2. Diesel fuel containing FAME in whatever concentration does not behave like petroleum-derived diesel, yet our Government is not telling us much about this.
According to the EU biofuels directive issued in 1999, labelling is unnecessary where the blend contains five per cent or less of FAME. So a supplying oil company does not need to tell its customers that a fuel is biodiesel at concentrations of less than five per cent. This has led to the farcical situation whereby a refiner supplied a fuels distributor with a biofuel blend without saying so. The distributor then added five per cent FAME to sell the product as an advertised biodiesel, resulting in a 10 per cent blend of much higher solvency and dispersancy, which cleaned storage tanks and blocked fuel filters in service station dispensers. In Hampshire, the trading standards authority was alerted to a series of filter blockages in service station dispensers resulting again from the unadvertised introduction of biodiesel.
One pump caused such suction as to burst the filter, allowing all the contamination into motorists' tanks. The trading standards officer was more interested in the fact that a substantially blocked filter would reduce the amount of fuel dispensed relative to that indicated, but the cost of the under-delivered fuel is tiny compared to the damage that solubilised resins or gums and dispersed particles will do to a modern, common-rail diesel engine, for which a new pump and injectors can cost more than £2,000.
Being more oxidatively and thermally unstable, FAME-containing blends tend to age more rapidly. This might not be a problem for a busy main-road fuel station, but what about a hospital's stand-by generators, which might not get through a whole tank of fuel in two years?
On the record, motor manufacturers seem to have gone with the flow of promoting biodiesel because it reduces our dependency on imported oil. Off the record they are more inclined to hint that the very least that biodiesel will do to the most sophisticated diesel engines is reduce their expected life. At a recent international conference on biofuels in Brussels, the motor industry admitted that biodiesel blended into a petroleum-based diesel produces a fuel which is less stable than conventional diesel, potentially resulting in injector fouling and power loss, that impurities in the biodiesel cause diesel exhaust catalyst damage, and that biodiesel causes engine oil dilution, thickening and, if not changed sooner, engine damage.
The oil industry has highlighted its concerns about the winter cold flow properties of biodiesel blends, oxidation and storage stability, fuel dilution of engine oil and the effects of contaminants from manufacturing processes and the distribution system. Fuel additive suppliers added foaming and the problems of water emulsification to the list.
However, it took a presentation by the Japanese Automobile Manufacturers Association (JAMA) to let the cat out of the European bag. Japan has been slower to embrace biodiesel and appears to be more rigorous in its evaluation. JAMA compared the oxidation resistance of B5 blends produced for the European market using more severe test conditions and pass criteria. All the fuels tested passed the European test but a third of the fuels failed the test now recommended in Japan. Given the number of diesel injection systems that are now failing under warranty in the UK, the suspicion must be that inadequate specifications are allowing unstable B5 blends on to the market. But with the secrecy covering biodiesel B5 blends, who knows?
Unconfused by the facts, the European Commission is pressing ahead with its political objective for B10 across Europe by 2020 but is now meeting a little more resistance from industry and some unexpected allies. The Royal Society for the Protection of Birds (RSPB), the World Wildlife Fund (WWF), Greenpeace, Oxfam and Friends of the Earth are all highlighting the stupidity of felling rainforest to export palm oil so that the EU can reduce its carbon footprint.
This is hardly joined-up government. Perhaps we should be told a bit more about the pros and the cons of biodiesel before we are forced to use it.
Peter L Barlow (BSc Hons, C.Chem, FRSC, FEI) worked at Shell for 32 years (20 as a research scientist and 12 years in technical marketing). Since 1999 he has been Environment, Health and Safety consultant to the Retail Motor Industry Federation (RMIF) and technical consultant to the Petrol Retailers Association (PRA).
Came across this rather one-sided but interesting article in The Telegraph at the weekend:
http://www.telegraph.co.uk/motoring/main.jhtml?xml=/motoring/2007/04/21/nosplit/mfbio21.xml
What's in your tank?
Are biofuels really a wonderful means of saving the planet, or is there a conspiracy of silence about the risks they pose? Peter Barlow reports
Some motorists get a warm feeling buying petrol or diesel with a biofuel component. After all, by reducing the consumption of crude oil and instead using fuel derived from renewable plants, which when burned releases only as much carbon dioxide as was absorbed by the growing crop, they are helping to save the planet from climate change, aren't they?
Take biodiesel, for example. Pure 100 per cent biodiesel (or B100) reduces new emissions of carbon dioxide (CO2) by some 60-80 per cent, so even a five per cent blend in conventional diesel (B5) will save up to four per cent on new CO2 emissions.
Biodiesel also has a higher cetane number, so there is less combustion knock and quieter engines, while its fatty properties provide good lubricity, giving lower fuel pump and injector wear. The natural products already contain some oxygen to provide lean burn with reduced hydrocarbon, carbon monoxide and particulate emissions. Add in the benefits to rural economies of growing the rape seed feedstock plus reduced oil imports and there are many purported benefits from adding biofuel components to conventional fuels.
Oil companies are progressively increasing the amount of B5 in UK diesel fuel in response to the Government's Renewable Transport Fuels Obligation, but what are the drawbacks? Unfortunately there are quite a few and the lack of information about them is beginning to resemble something of a conspiracy.
Natural fats are too viscous to be used in high-performance, low-emission diesel engines, so, via a process known as transesterification, the natural fat is changed using methyl alcohol and a catalyst into the Fatty Acid Methyl Ester (FAME). Most people concerned about their cardiovascular health will scan the nutrition boxes on packaged foods for fat content and the balance between saturated and monounsaturated and polyunsaturated fat. Unsaturated good! Saturated bad! Is it the same for fats in fuels? Well, yes and no. Highly saturated beef fat, or palm oil, crystalises at a higher temperature than the more unsaturated rapeseed oil or fish oil and as a result is more likely to cause winter waxing in diesel fuel.
Unsaturated fats in the body are more reactive and can be metabolised more easily. That is good. In biodiesel the methyl esters of the same unsaturated fat are also more reactive, but this makes them unstable to heat and oxygen, which is decidedly bad news. The chemistry of FAME increases its affinity with water, its conductivity, its reactivity and its bioavailability. For good measure, methyl esters are known degreasing solvents. They lift accumulated resins, gums, polymeric material, fuel additives and debris from storage tank walls and distribution pipework and carry them forward to block filters, or more worryingly, to pass through them. These may be filters on dispensers at service stations or fuel filters protecting your engine.
Being biodegradable might be good for the environment if there is a fuel spillage, but microbiological attack in storage tanks is not. Like humans, microbes need food and water. They live in the water and eat the fuel to grow. As they multiply they produce acid waste, which can corrode and perforate steel tanks. They form mats of slime that clog filters and plug fuel lines. To cap it all, microbial growth in biodiesel occurs at up to four times the rate in conventional diesel and is very expensive to expel. To date there have been outbreaks of microbiological infestations in biodiesel tanks in the North West, North East and South East.
The higher solubility of water in biodiesel can, under the right conditions, also trigger hydrolysis - decomposition by reaction with water. The reaction (Fatty) Acid + (Methyl) Alcohol = (Methyl) Ester + Water is reversible, so water plus diesel esters can produce methyl alcohol plus fatty acids. The acids released cause corrosion. This raises the issue of materials compatibility. Are all the materials - metals, alloys, polymers and plastics - in the present distribution system and retailing system compatible with biodiesel and its degradation products? The simple answer is no, they are not.
Consequently, with biodiesel there are increased risk factors and associated costs, and the greater the methyl ester concentration, the higher the risk. So B10 is more risky than B5, which is more risky than B2. Diesel fuel containing FAME in whatever concentration does not behave like petroleum-derived diesel, yet our Government is not telling us much about this.
According to the EU biofuels directive issued in 1999, labelling is unnecessary where the blend contains five per cent or less of FAME. So a supplying oil company does not need to tell its customers that a fuel is biodiesel at concentrations of less than five per cent. This has led to the farcical situation whereby a refiner supplied a fuels distributor with a biofuel blend without saying so. The distributor then added five per cent FAME to sell the product as an advertised biodiesel, resulting in a 10 per cent blend of much higher solvency and dispersancy, which cleaned storage tanks and blocked fuel filters in service station dispensers. In Hampshire, the trading standards authority was alerted to a series of filter blockages in service station dispensers resulting again from the unadvertised introduction of biodiesel.
One pump caused such suction as to burst the filter, allowing all the contamination into motorists' tanks. The trading standards officer was more interested in the fact that a substantially blocked filter would reduce the amount of fuel dispensed relative to that indicated, but the cost of the under-delivered fuel is tiny compared to the damage that solubilised resins or gums and dispersed particles will do to a modern, common-rail diesel engine, for which a new pump and injectors can cost more than £2,000.
Being more oxidatively and thermally unstable, FAME-containing blends tend to age more rapidly. This might not be a problem for a busy main-road fuel station, but what about a hospital's stand-by generators, which might not get through a whole tank of fuel in two years?
On the record, motor manufacturers seem to have gone with the flow of promoting biodiesel because it reduces our dependency on imported oil. Off the record they are more inclined to hint that the very least that biodiesel will do to the most sophisticated diesel engines is reduce their expected life. At a recent international conference on biofuels in Brussels, the motor industry admitted that biodiesel blended into a petroleum-based diesel produces a fuel which is less stable than conventional diesel, potentially resulting in injector fouling and power loss, that impurities in the biodiesel cause diesel exhaust catalyst damage, and that biodiesel causes engine oil dilution, thickening and, if not changed sooner, engine damage.
The oil industry has highlighted its concerns about the winter cold flow properties of biodiesel blends, oxidation and storage stability, fuel dilution of engine oil and the effects of contaminants from manufacturing processes and the distribution system. Fuel additive suppliers added foaming and the problems of water emulsification to the list.
However, it took a presentation by the Japanese Automobile Manufacturers Association (JAMA) to let the cat out of the European bag. Japan has been slower to embrace biodiesel and appears to be more rigorous in its evaluation. JAMA compared the oxidation resistance of B5 blends produced for the European market using more severe test conditions and pass criteria. All the fuels tested passed the European test but a third of the fuels failed the test now recommended in Japan. Given the number of diesel injection systems that are now failing under warranty in the UK, the suspicion must be that inadequate specifications are allowing unstable B5 blends on to the market. But with the secrecy covering biodiesel B5 blends, who knows?
Unconfused by the facts, the European Commission is pressing ahead with its political objective for B10 across Europe by 2020 but is now meeting a little more resistance from industry and some unexpected allies. The Royal Society for the Protection of Birds (RSPB), the World Wildlife Fund (WWF), Greenpeace, Oxfam and Friends of the Earth are all highlighting the stupidity of felling rainforest to export palm oil so that the EU can reduce its carbon footprint.
This is hardly joined-up government. Perhaps we should be told a bit more about the pros and the cons of biodiesel before we are forced to use it.
Peter L Barlow (BSc Hons, C.Chem, FRSC, FEI) worked at Shell for 32 years (20 as a research scientist and 12 years in technical marketing). Since 1999 he has been Environment, Health and Safety consultant to the Retail Motor Industry Federation (RMIF) and technical consultant to the Petrol Retailers Association (PRA).
