Vegetable oil fuel

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Waste vegetable oil that has been filtered Used vegetable cooking oil.png
Waste vegetable oil that has been filtered

Vegetable oil can be used as an alternative fuel in diesel engines and in heating oil burners. When vegetable oil is used directly as a fuel, in either modified or unmodified equipment, it is referred to as straight vegetable oil (SVO) or pure plant oil (PPO). Conventional diesel engines can be modified to help ensure that the viscosity of the vegetable oil is low enough to allow proper atomization of the fuel. This prevents incomplete combustion, which would damage the engine by causing a build-up of carbon. Straight vegetable oil can also be blended with conventional diesel or processed into biodiesel, HVO or bioliquids for use under a wider range of conditions.

Contents

History

Rudolf Diesel, inventor of the diesel engine. Rudolf Diesel.jpg
Rudolf Diesel, inventor of the diesel engine.

Rudolf Diesel was the father of the engine which bears his name. His first attempts were to design an engine to run on coal dust, but he later designed his engine to run on vegetable oil. The idea, he hoped, would make his engines more attractive to farmers having a source of fuel readily available. In a 1912 presentation to the British Institute of Mechanical Engineers, he cited a number of efforts in this area and remarked, "The fact that fat oils from vegetable sources can be used may seem insignificant today, but such oils may perhaps become in course of time of the same importance as some natural mineral oils and the tar products are now." [1]

Periodic petroleum shortages spurred research into vegetable oil as a diesel substitute during the 1930s and 1940s, and again in the 1970s and early 1980s when straight vegetable oil enjoyed its highest level of scientific interest. The 1970s also saw the formation of the first commercial enterprise to allow consumers to run straight vegetable oil in their automobiles, Elsbett of West Germany. In the 1990s Bougainville conflict, islanders cut off from oil supplies due to a blockade fueled their vehicles with coconut oil. [2]

Application and usability

Modified fuel systems

Most diesel car engines are suitable for the use of straight vegetable oil (SVO), also commonly called pure plant oil (PPO), with certain modifications. Principally, the viscosity and surface tension of the SVO/PPO must be reduced by preheating it, typically by using waste heat from the engine or electricity; otherwise, poor atomization, incomplete combustion, and carbonization may result. One common solution is to add a heat exchanger and an additional fuel tank for the petrodiesel or biodiesel blend and to switch between this additional tank and the main tank of SVO/PPO. The engine is started on diesel, switched over to vegetable oil as soon as it is warmed up, and switched back to diesel shortly before being switched off to ensure that no vegetable oil remains in the engine or fuel lines when it is started from cold again. In colder climates it is often necessary to heat the vegetable oil fuel lines and tank as it can become very viscous and even solidify.

Single-tank conversions were developed largely in Germany and are now used throughout Europe. These conversions are designed to provide reliable operation with rapeseed oil that meets the German rapeseed oil fuel standard DIN 51605. Modifications to the engine's cold start regime assist combustion on start up and during the engine warm up phase. Suitably modified indirect injection (IDI) engines have proven to be operable with 100% PPO down to temperatures of −10 °C (14 °F). Direct injection (DI) engines generally have to be preheated with a block heater or diesel fired heater. The exception is the VW TDI (Turbocharged Direct Injection) engine for which a number of German companies offer single-tank conversions. For long-term durability it has been found necessary to decrease the oil change interval and pay increased attention to engine maintenance.

Unmodified indirect injection engines

Many cars powered by indirect injection engines supplied by in-line injection pumps, or mechanical Bosch injection pumps are capable of running on pure SVO/PPO in all but winter temperatures. The most popular of these are the OM616 and OM617 engines found in the Mercedes-Benz W123 and W124 vehicles manufactured from 1980 through 1985. Indirect injection Mercedes-Benz vehicles with in-line injection pumps and cars featuring the PSA XUD engine tend to perform reasonably, especially as the latter is normally equipped with a coolant heated fuel filter. Engine reliability would depend on the condition of the engine. Attention to maintenance of the engine, particularly of the fuel injectors, cooling system and glow plugs will help to provide longevity. Ideally the engine would be converted. [3]

Vegetable oil blending

The relatively high kinematic viscosity of vegetable oils must be reduced to make them compatible with conventional compression-ignition engines and fuel systems. Cosolvent blending is a low-cost and easy-to-adapt technology that reduces viscosity by diluting the vegetable oil with a low-molecular-weight solvent. [4] This blending, or "cutting", has been done with diesel fuel, kerosene, and gasoline, among others; however, opinions vary as to the efficacy of this. Noted problems include higher rates of wear and failure in fuel pumps and piston rings when using blends. [3]

Home heating

When liquid fuels made from biomass are used for energy purposes other than transport, they are called bioliquids or biofuels. [5]

With often minimal modification, most residential furnaces and boilers that are designed to burn No. 2 heating oil can be made to burn either biodiesel or filtered, preheated waste vegetable oil (WVO). New standard oil burners are certified to operate on 20% biodiesel (B-20). Higher blends are possible with care, since biodiesel tends to liberate existing tarry deposits in fuel tank, which may tend to clog one or more filters. Conventional oil burners tend to clog and char if more than a smaller fraction of vegetable oil is mixed with conventional oil fuel. If the vegetable oil is cleaned at home by the consumer, WVO can result in considerable savings. Many restaurants will receive a minimal amount for their used cooking oil, and processing to a biofuel is fairly simple and inexpensive. Making the oil into biodiesel involves some toxic and hazardous chemical transformations. Burning filtered WVO directly is somewhat more problematic, since it is more viscous and has a higher ignition temperature; nonetheless, its burning can be accomplished with suitable preheating or burners designed to operate on it. WVO can thus be an economical heating option for those with the necessary mechanical and experimental aptitude.

Combined heat and power

A number of companies offer compression ignition engine generators optimized to run on plant oils where the waste engine heat is recovered for heating.

Properties

The main form of SVO/PPO used in the UK is rapeseed oil (also known as canola oil, primarily in the United States and Canada) which has a freezing point of −10 °C (14 °F).[ citation needed ] However the use of sunflower oil, which gels at around −12 °C (10 °F), [6] is currently being investigated as a means of improving cold-weather starting. However, oils with lower gelling points tend to be less saturated (leading to a higher iodine number) and polymerize more easily in the presence of atmospheric oxygen.

Material compatibility

Polymerization also has been consequentially linked to catastrophic component failures such as injection pump shaft seizure and breakage, injector tip failure leading to various and/or combustion chamber components damaged. Most metallurgical problems such as corrosion and electrolysis are related to water-based contamination or poor choices of plumbing (such as copper or zinc) which can cause gelling – even with petroleum-based fuels.

Temperature effects

Some Pacific island nations are using coconut oil as fuel to reduce their expenses and their dependence on imported fuels while helping stabilize the coconut oil market. Coconut oil is only usable where temperatures do not drop below 17 degrees Celsius (63 degrees Fahrenheit), unless two-tank SVO/PPO kits or other tank-heating accessories, etc. are used. The same techniques developed to use, for example, canola and other oils in cold climates can be implemented to make coconut oil usable in temperatures lower than 17 degrees Celsius (63 degrees Fahrenheit)

Availability

Biodiesel bus in Sweden Rapsolja bus.jpg
Biodiesel bus in Sweden

Recycled vegetable oil

Recycled vegetable oil, also termed used vegetable oil (UVO), waste vegetable oil (WVO), used cooking oil (UCO), [7] or yellow grease (in commodities exchange), is recovered from businesses and industry that use the oil for cooking.

As of 2000, the United States was producing in excess of 11 billion liters (2.9 billion U.S. gallons) of recycled vegetable oil annually, mainly from industrial deep fryers in potato processing plants, snack food factories, and fast food restaurants. If all those 11 billion liters could be recycled and used to replace the energy equivalent amount of petroleum (an ideal case), almost 1% of US oil consumption could be offset. [8] Utilizing recycled vegetable oil as a replacement for standard petroleum-derived fuels like gasoline would reduce the price of gasoline by preserving the supply of petroleum.

Virgin vegetable oil

Virgin vegetable oil, also termed pure plant oil or straight vegetable oil, is extracted from plants solely for use as fuel. In contrast to used vegetable oil, is not a byproduct of other industries, and thus its prospects for use as fuel are not limited by the capacities of other industries. [ citation needed ] Production of vegetable oils for use as fuels is theoretically limited only by the agricultural capacity of a given economy. However, doing so detracts from the supply of other uses of pure vegetable oil.

Taxation of fuel

Taxation on SVO/PPO as a road fuel varies from country to country. It is possible that the revenue departments in many countries are even unaware of its use or consider it too insignificant to legislate. Germany used to have 0% taxation, resulting in it being a leader in most developments of the fuel use.

See also

Related Research Articles

A lubricant is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. The property of reducing friction is known as lubricity.

<span class="mw-page-title-main">Diesel fuel</span> Liquid fuel used in diesel engines

Diesel fuel, also called diesel oil or historically heavy oil, is any liquid fuel specifically designed for use in a diesel engine, a type of internal combustion engine in which fuel ignition takes place without a spark as a result of compression of the inlet air and then injection of fuel. Therefore, diesel fuel needs good compression ignition characteristics.

<span class="mw-page-title-main">Biofuel</span> Type of biological fuel

Biofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels such as oil. Biofuel can be produced from plants or from agricultural, domestic or industrial biowaste. Biofuels are mostly used for transportation, but can also be used for heating and electricity. Biofuels are regarded as a renewable energy source. The use of biofuel has been subject to criticism regarding the "food vs fuel" debate, varied assessments of their sustainability, and possible deforestation and biodiversity loss as a result of biofuel production.

<span class="mw-page-title-main">Biodiesel</span> Fuel made from vegetable oils or animal fats

Biodiesel is a renewable biofuel, a form of diesel fuel, derived from biological sources like vegetable oils, animal fats, or recycled greases, and consisting of long-chain fatty acid esters. It is typically made from fats.

<span class="mw-page-title-main">Vegetable oil</span> Oil extracted from seeds or from other parts of fruits

Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are mixtures of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or fats from seeds. Olive oil, palm oil, and rice bran oil are examples of fats from other parts of fruits. In common usage, vegetable oil may refer exclusively to vegetable fats which are liquid at room temperature. Vegetable oils are usually edible.

<span class="mw-page-title-main">Motor oil</span> Lubricant used for lubrication of internal combustion engines

Motor oil, engine oil, or engine lubricant is any one of various substances used for the lubrication of internal combustion engines. They typically consist of base oils enhanced with various additives, particularly antiwear additives, detergents, dispersants, and, for multi-grade oils, viscosity index improvers. The main function of motor oil is to reduce friction and wear on moving parts and to clean the engine from sludge and varnish (detergents). It also neutralizes acids that originate from fuel and from oxidation of the lubricant (detergents), improves the sealing of piston rings, and cools the engine by carrying heat away from moving parts.

<span class="mw-page-title-main">Fuel oil</span> Petroleum product burned to generate motive power or heat

Fuel oil is any of various fractions obtained from the distillation of petroleum. Such oils include distillates and residues. Fuel oils include heavy fuel oil, marine fuel oil (MFO), furnace oil (FO), gas oil (gasoil), heating oils, diesel fuel, and others.

<span class="mw-page-title-main">Alternative fuel</span> Fuels from sources other than fossil fuels

Alternative fuels, also known as non-conventional and advanced fuels, are fuels derived from sources other than petroleum. Alternative fuels include gaseous fossil fuels like propane, natural gas, methane, and ammonia; biofuels like biodiesel, bioalcohol, and refuse-derived fuel; and other renewable fuels like hydrogen and electricity.

<span class="mw-page-title-main">Yellow grease</span> Recycled cooking oil

Yellow grease, also termed used cooking oil (UCO), used vegetable oil (UVO), recycled vegetable oil, or waste vegetable oil (WVO), is recovered from businesses and industry that use the oil for cooking.

Cetane number (CN) is an indicator of the combustion speed of diesel fuel and compression needed for ignition. It plays a similar role for diesel as octane rating does for gasoline. The CN is an important factor in determining the quality of diesel fuel, but not the only one; other measurements of diesel fuel's quality include energy content, density, lubricity, cold-flow properties and sulphur content.

Heating oil is any petroleum product or other oil used for heating; it is a fuel oil. Most commonly, it refers to low viscosity grades of fuel oil used for furnaces or boilers use for home heating and in other buildings. Home heating oil is often abbreviated as HHO.

Pyrolysis oil, sometimes also known as bio-crude or bio-oil, is a synthetic fuel with limited industrial application and under investigation as substitute for petroleum. It is obtained by heating dried biomass without oxygen in a reactor at a temperature of about 500 °C (900 °F) with subsequent cooling, separation from the aqueous phase and other processes. Pyrolysis oil is a kind of tar and normally contains levels of oxygen too high to be considered a pure hydrocarbon. This high oxygen content results in non-volatility, corrosiveness, partial miscibility with fossil fuels, thermal instability, and a tendency to polymerize when exposed to air. As such, it is distinctly different from petroleum products. Removing oxygen from bio-oil or nitrogen from algal bio-oil is known as upgrading.

Neste MY Renewable Diesel is a vegetable oil refining fuel production process commercialized by the Finnish oil and refining company Neste. Whether as an admixture or in its pure form, Neste MY Renewable Diesel is able to supplement or partially replace diesel fuel without problems. Neste MY Renewable Diesel guarantees that every gallon sold meets ASTM D975 and EN 15940 specifications in compliance with OEM standards.

<span class="mw-page-title-main">Vegetable oils as alternative energy</span> Fuel made from plants

Vegetable oils are increasingly used as a substitute for fossil fuels. Vegetable oils are the basis of biodiesel, which can be used like conventional diesel. Some vegetable oil blends are used in unmodified vehicles, but straight vegetable oil often needs specially prepared vehicles which have a method of heating the oil to reduce its viscosity and surface tension, sometimes specially made injector nozzles, increased injection pressure and stronger glow-plugs, in addition to fuel pre-heating is used. Another alternative is vegetable oil refining.

The biofuel sector in the United Kingdom, under the auspices of the government's Renewable Transport Fuel Obligation (RTFO), has been progressing towards enhanced sustainable energy solutions. Marking a significant stride in this direction was the government's endorsement and introduction of E10 biofuel in late 2021. This fuel blend, consisting of 90% regular unleaded gasoline and 10% ethanol, was introduced as part of an initiative to reduce greenhouse gas emissions (GHG) from transport fuels. The introduction of E10 led to a shift in the renewable fuel landscape in the UK, particularly influencing an increase in the utilization of non-waste feedstocks. In the year 2022, the biofuel sector, as per government reports, achieved a reduction in GHG emissions by 82% in comparison to traditional fossil fuels.

Crankcase dilution is a phenomenon of internal combustion engines in which unburned diesel or gasoline accumulates in the crankcase. Excessively rich fuel mixture or incomplete combustion allows a certain amount of fuel to pass down between the pistons and cylinder walls and dilute the engine oil. It is more common in situations where fuel is injected at a very high pressure, such as in a direct-injected diesel engine.

<span class="mw-page-title-main">Automotive oil recycling</span> The process of recycling used engine and motor oils

Automotive oil recycling involves the recycling of used oils and the creation of new products from the recycled oils, and includes the recycling of motor oil and hydraulic oil. Oil recycling also benefits the environment: increased opportunities for consumers to recycle oil lessens the likelihood of used oil being dumped on lands and in waterways. For example, one gallon of motor oil dumped into waterways has the potential to pollute one million gallons of water.

<span class="mw-page-title-main">Bioliquids</span>

Bioliquids are liquid fuels made from biomass for energy purposes other than transport.

<span class="mw-page-title-main">Internal combustion engine</span> Engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber

An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.

<span class="mw-page-title-main">Cooking oil</span> Oil consumed by humans, of vegetable or animal origin

Cooking oil is a plant or animal liquid fat used in frying, baking, and other types of cooking. Oil allows higher cooking temperatures than water, making cooking faster and more flavorful, while likewise distributing heat, reducing burning and uneven cooking. It sometimes imparts its own flavor. Cooking oil is also used in food preparation and flavoring not involving heat, such as salad dressings and bread dips.

References

  1. ↑ Knothe, Gerhard (2001). "Historical Perspectives on Vegetable Oil-Based Diesel Fuels" (PDF). Inform. 12 (11). American Oil Chemists' Society: 1103–1107. Retrieved 2021-04-20.
  2. ↑ The Coconut Revolution at IMDb OOjs UI icon edit-ltr-progressive.svg (2000) a documentary film
  3. 1 2 Pacific Islands Applied Geoscience Commission: "Coconut Oil Fuel Research in the Republic of the Marshall Islands"
  4. ↑ Dunn, R. O. (2008). "Low-Temperature Flow Properties of Vegetable Oil/Cosolvent Blend Diesel Fuels" (PDF). ddr.nal.usda.gov. Archived from the original (PDF) on 14 August 2011. Retrieved 23 April 2011.
  5. ↑ "Renewable Energy Association Yearbook 2009" (PDF). Archived from the original (PDF) on 2011-07-24.
  6. ↑ Gregg, Forest. "Fuel Properties of Various Oils and Fats" . Retrieved 2009-12-04.
  7. ↑ Kotrba, Ron (September 23, 2014). "IncBio contracted to supply 2.4 MMgy biodiesel plant to Greece". Biodiesel Magazine. Retrieved 11 October 2014.
  8. ↑ See Greenhouse gas emissions by the United States
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