Just a brief update.
I've started construction of the processor and, armed with newfound knowledge courtesy of my plumber pal Arif, have been busy making good progress. Today I built a stand for the reactor out of 2x2's and continued with the remaining pipework, namely soldering the venturi together (I'll explain what that is another day).
An empty butane can and rumbling tum finally stopped play this evening as the sun went down. I have some pics which I'll endeavour to put up tomorrow, as right now, I'm knackered.
Tuesday 10 May 2011
Monday 9 May 2011
What is biodiesel?
In a nutshell, biodiesel is a diesel fuel produced from feedstock; that is, plant or animal fats, which are refined through a chemical process to make it suitable for use in diesel engined vehicles.
The most popular feedstock for producing biodiesel is common household vegetable oil. The alternative fuel community generally refer to this in one of two ways: WVO (waste vegetable oil) or SVO (straight vegetable oil). The difference between the two is whether the oil has previously been used for cooking purposes (and is now waste) or whether it is brand new and unoutched.
This is important, as the process of cooking introduces water and other impurities into the oil, which affects the quality of the oil being input into the reactor and consequently the level of catalyst agent chemicals required to achieve a succesful conversion to high quality biodiesel.
It should be noted, that use of vegetable oil in a diesel engine does not necessarily require conversion into biodiesel. The engine that Rudolf Diesel designed was designed to be as forgiving as possible with regard to the combustible material used in it. Unlike a petrol engine, which ignites highly flammable vapour with the use of a spark to achieve combustion, a diesel engine uses high pressure to cause the combustion of a pre heated oil. As such, in theory diesel engines should run quite happily on straight vegetable oil with no requirement for conversion into biodiesel.
The reality is not quite as black and white. Modern engines, particularly of the "common rail" type, are controlled by onboard computers which determine, amongst other things, the rate at which the fuel injectors must introduce fuel into the combustion chamber. This rate is determined by the engine manufacturer using the viscosity (resistance; gloopiness if you will) of mineral diesel fuel in order to deliver the optimum fuel to the engine without wastage. Vegetable oil has a higher viscosity than mineral diesel meaning that it is more gloopy than mineral diesel. Although vegetable oil thins out as it is heated, when it cools its viscosity rises again. This poses a risk for "gumming up" of parts in a vehicle's fuel line and engine when the engine is not running and therefore heating the oil to thin it out. As such, straight vegetable oil is not recommended for most modern vehicles. Vehicle conversion kits exist to preheat fuel within the fuel lines before it reaches the injectors but these do not heat fuel that has already been pumped into the system.
So the solution to this problem is to permanently lower the viscosity of the oil to be of a similar level to that of mineral diesel (sometimes referred to online as dino diesel, DERV [Diesel Engined Road Vehicle] or ULSD [Ultra Low Sulphur Diesel]). This is where biodiesel comes in.
Part of the uncertainty surrounding biodiesel is the rumour doing the rounds that you can "take some used cooking oil, strain it through a pillow and add some solvents" then put it in your car.
This does NOT produce biodiesel. It produces a biofuel which, given a very particular set of circumstances (not least a very forgiving engine and fuel lines!), can be used in some diesel engines. Biodiesel is a high quality diesel fuel produced by means of a chemical process known as transesterification (more on that later) and is wholly different to the aforementioned biofuel bodge job. Unfortunately there are less scrupulous types out there who have been passing low quality biofuel off as biodiesel in the commercial space which has ruined motorists' engines and caused concern at the mention of biodiesel in some circles.
The reality is that all diesel engines in the UK today use biodiesel. A 2005 EU roadmap stated that by the end of 2010 all diesel sold on EU forecourts must be a minimum of 5% biodiesel, which raises another point of note: biodiesel and mineral diesel can coexist in the same tank quite happily, and some biodiesel users opt to run a mix of the two, denoted by the percentage of biodiesel in the mix; e.g B100 is 100% biodiesel, B50 is a 50/50 mix with mineral diesel, B20 is 80% mineral and 20% biodiesel and so on. All EU diesel is B5. The point is, provided the biodiesel is produced to a high standard, consistently, it can in theory be used in any diesel engine. It is important therefore, to understand the process involved (transesterification) in order to achieve the optimal output each time.
As ever, oil and fuel are big business, and there is a wider ethical debate of using land which could be used to grow food to feed the starving being used as sites for popular feedstock for biodiesel. This is a very valid debate, however as I am focussing on small scale home production using waste (and therefore recycled) feedstock, rather than growing fields of vegetation to extract oil from, I won't dwell on it too much here.
The most popular feedstock for producing biodiesel is common household vegetable oil. The alternative fuel community generally refer to this in one of two ways: WVO (waste vegetable oil) or SVO (straight vegetable oil). The difference between the two is whether the oil has previously been used for cooking purposes (and is now waste) or whether it is brand new and unoutched.
This is important, as the process of cooking introduces water and other impurities into the oil, which affects the quality of the oil being input into the reactor and consequently the level of catalyst agent chemicals required to achieve a succesful conversion to high quality biodiesel.
It should be noted, that use of vegetable oil in a diesel engine does not necessarily require conversion into biodiesel. The engine that Rudolf Diesel designed was designed to be as forgiving as possible with regard to the combustible material used in it. Unlike a petrol engine, which ignites highly flammable vapour with the use of a spark to achieve combustion, a diesel engine uses high pressure to cause the combustion of a pre heated oil. As such, in theory diesel engines should run quite happily on straight vegetable oil with no requirement for conversion into biodiesel.
The reality is not quite as black and white. Modern engines, particularly of the "common rail" type, are controlled by onboard computers which determine, amongst other things, the rate at which the fuel injectors must introduce fuel into the combustion chamber. This rate is determined by the engine manufacturer using the viscosity (resistance; gloopiness if you will) of mineral diesel fuel in order to deliver the optimum fuel to the engine without wastage. Vegetable oil has a higher viscosity than mineral diesel meaning that it is more gloopy than mineral diesel. Although vegetable oil thins out as it is heated, when it cools its viscosity rises again. This poses a risk for "gumming up" of parts in a vehicle's fuel line and engine when the engine is not running and therefore heating the oil to thin it out. As such, straight vegetable oil is not recommended for most modern vehicles. Vehicle conversion kits exist to preheat fuel within the fuel lines before it reaches the injectors but these do not heat fuel that has already been pumped into the system.
So the solution to this problem is to permanently lower the viscosity of the oil to be of a similar level to that of mineral diesel (sometimes referred to online as dino diesel, DERV [Diesel Engined Road Vehicle] or ULSD [Ultra Low Sulphur Diesel]). This is where biodiesel comes in.
Part of the uncertainty surrounding biodiesel is the rumour doing the rounds that you can "take some used cooking oil, strain it through a pillow and add some solvents" then put it in your car.
This does NOT produce biodiesel. It produces a biofuel which, given a very particular set of circumstances (not least a very forgiving engine and fuel lines!), can be used in some diesel engines. Biodiesel is a high quality diesel fuel produced by means of a chemical process known as transesterification (more on that later) and is wholly different to the aforementioned biofuel bodge job. Unfortunately there are less scrupulous types out there who have been passing low quality biofuel off as biodiesel in the commercial space which has ruined motorists' engines and caused concern at the mention of biodiesel in some circles.
The reality is that all diesel engines in the UK today use biodiesel. A 2005 EU roadmap stated that by the end of 2010 all diesel sold on EU forecourts must be a minimum of 5% biodiesel, which raises another point of note: biodiesel and mineral diesel can coexist in the same tank quite happily, and some biodiesel users opt to run a mix of the two, denoted by the percentage of biodiesel in the mix; e.g B100 is 100% biodiesel, B50 is a 50/50 mix with mineral diesel, B20 is 80% mineral and 20% biodiesel and so on. All EU diesel is B5. The point is, provided the biodiesel is produced to a high standard, consistently, it can in theory be used in any diesel engine. It is important therefore, to understand the process involved (transesterification) in order to achieve the optimal output each time.
As ever, oil and fuel are big business, and there is a wider ethical debate of using land which could be used to grow food to feed the starving being used as sites for popular feedstock for biodiesel. This is a very valid debate, however as I am focussing on small scale home production using waste (and therefore recycled) feedstock, rather than growing fields of vegetation to extract oil from, I won't dwell on it too much here.
Why this blog? And why biodiesel?
Quite simply, this blog has been created to document my foray into production of biodiesel, an alternative fuel to mineral diesel.
As is common knowledge, the price of crude oil derived fuels continues to rise, yet the demand for them does not wane. In addition, waste gases from combusted mineral fuels, despite increasingly stringent emission regulations, continues to pollute and contribute toward climate change.
The cost both financially and environmentally is unsustainable.
Biodiesel is one of a number of alternative fuels. Along with bioethanol, it is the most widely available. Alternative fuels are fuels which can be used in place of mineral fuels, namely diesel and petroleum (gasoline in North America).
There appears to be a lot of confusion surrounding biodiesel, and as with any important undertaking, it is vital to conduct adequate research to understand the whys and wherefors of the task in hand. My aim in this blog is to document both the research I have done to start biodiesel production and my progress in producing it.
As is common knowledge, the price of crude oil derived fuels continues to rise, yet the demand for them does not wane. In addition, waste gases from combusted mineral fuels, despite increasingly stringent emission regulations, continues to pollute and contribute toward climate change.
The cost both financially and environmentally is unsustainable.
Biodiesel is one of a number of alternative fuels. Along with bioethanol, it is the most widely available. Alternative fuels are fuels which can be used in place of mineral fuels, namely diesel and petroleum (gasoline in North America).
There appears to be a lot of confusion surrounding biodiesel, and as with any important undertaking, it is vital to conduct adequate research to understand the whys and wherefors of the task in hand. My aim in this blog is to document both the research I have done to start biodiesel production and my progress in producing it.
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