In addition to landfills, anaerobic decomposition can also be implemented on ranch es and livestock farms. Manure and other animal waste can be converted to sustainably meet the energy needs of the farm.
Biofuel Biomass is the only renewable energy source that can be converted into liquid biofuels such as ethanol and biodiesel. Biofuel is used to power vehicles, and is being produced by gasification in countries such as Sweden, Austria, and the United States.
Ethanol is made by ferment ing biomass that is high in carbohydrates, such as sugar cane, wheat, or corn. Biodiesel is made from combining ethanol with animal fat, recycled cooking fat, or vegetable oil.
Biofuels do not operate as efficiently as gasoline. However, they can be blended with gasoline to efficiently power vehicles and machinery, and do not release the emissions associated with fossil fuels. Ethanol requires acres of farmland to grow biocrops usually corn. About 1, liters gallons of ethanol is produced by an acre of corn. But this acreage is then unavailable for growing crops for food or other uses.
Growing enough corn for ethanol also creates a strain on the environment because of the lack of variation in planting, and the high use of pesticides.
Ethanol has become a popular substitute for wood in residential fireplaces. When it is burned, it gives off heat in the form of flames, and water vapor instead of smoke.
Biochar Biochar, produced during pyrolysis, is valuable in agricultural and environmental use. When biomass rots or burns naturally or by human activity , it releases high amounts of methane and carbon dioxide into the atmosphere. However, when biomass is charred, it sequester s, or stores, its carbon content. When biochar is added back to the soil, it can continue to absorb carbon and form large underground stores of sequestered carbon—carbon sinks—that can lead to negative carbon emissions and healthier soil.
Biochar also helps enrich the soil. It is porous. When added back to the soil, biochar absorbs and retains water and nutrients.
This enhances the soil and leads to significantly higher plant growth. Black Liquor When wood is processed into paper, it produces a high-energy, toxic substance called black liquor. Until the s, black liquor from paper mills was considered a waste product and dumped into nearby water sources. With the invention of the recovery boiler in the s, black liquor could be recycled and used to power the mill.
In the U. More recently, Sweden has experimented in gasifying black liquor to produce syngas, which can then be used to generate electricity. Hydrogen Fuel Cells Biomass is rich in hydrogen, which can be chemically extracted and used to generate power and to fuel vehicles. Stationary fuel cells are used to generate electricity in remote locations, such as spacecraft and wilderness areas. Yosemite National Park in the U. Hydrogen fuel cells may hold even more potential as an alternative energy source for vehicles.
The U. Department of Energy estimates that biomass has the potential to produce 40 million tons of hydrogen per year. This would be enough to fuel million vehicles. Currently, hydrogen fuel cells are used to power buses, forklifts, boats, and submarines, and are being tested on airplanes and other vehicles. However, there is a debate as to whether this technology will become sustainable or economically possible. The energy that it takes to isolate, compress, package, and transport the hydrogen does not leave a high quantity of energy for practical use.
The carbon cycle is the process by which carbon is exchanged between all layers of the Earth: atmosphere , hydrosphere , biosphere , and lithosphere. The carbon cycle takes many forms. It is exchanged through photosynthesis, decomposition, respiration, and human activity. Carbon that is absorbed by soil as an organism decomposes, for example, may be recycled as a plant releases carbon-based nutrients into the biosphere through photosynthesis. Under the right conditions, the decomposing organism may become peat , coal, or petroleum before being extract ed through natural or human activity.
Between periods of exchange, carbon is sequestered, or stored. The carbon in fossil fuels has been sequestered for millions of years. When fossil fuels are extracted and burned for energy, their sequestered carbon is released into the atmosphere.
Fossil fuels do not re-absorb carbon. In contrast to fossil fuels, biomass comes from recently living organisms.
The carbon in biomass can continue to be exchanged in the carbon cycle. In order to effectively allow Earth to continue the carbon cycle process, however, biomass materials such as plants and forests have to be sustainably farmed. It takes decades for trees and plants such as switchgrass to re-absorb and sequester carbon.
Uprooting or disturbing the soil can be extremely disruptive to the process. A steady and varied supply of trees, crops, and other plants is vital for maintaining a healthy environment.
Algal Fuel Algae is a unique organism that has enormous potential as a source of biomass energy. Algae, whose most familiar form is seaweed , produces energy through photosynthesis at a much quicker rate than any other biofuel feedstock—up to 30 times faster than food crops! Algae can be grown in ocean water, so it does not deplete freshwater resources.
It also does not require soil, and therefore does not reduce arable land that could potentially grow food crops. Although algae releases carbon dioxide when it is burned, it can be farmed and replenished as a living organism. As it is replenished, it releases oxygen, and absorbs pollutant s and carbon emissions. Algae takes up much less space than other biofuel crops. Department of Energy estimates that it would only take approximately 38, square kilometers 15, square miles, an area less than half the size of the U.
Algae contains oils that can be converted to a biofuel. At the Aquaflow Bionomic Corporation in New Zealand, for example, algae is processed with heat and pressure. Algae is an excellent filter that absorbs carbon emissions. Bioenergy Ventures, a Scottish firm, has developed a system in which carbon emissions from a whiskey distillery are funneled to an algae pool. The algae flourishes with the additional carbon dioxide.
When the algae die after about a week they are collected, and their lipid s oils are converted into biofuel or fish food. Algae has enormous potential as an alternative energy source. However, processing it into usable forms is expensive.
The cost will likely come down, but it is currently out of reach for most developing economies. People and Biomass Advantages Biomass is a clean, renewable energy source. Its initial energy comes from the sun, and plants or algae biomass can regrow in a relatively short amount of time. A method of depositing an oriented polycrystalline perovskite film wherein each crystal grain is grown perpendicular to the growth substrate, allowing for significantly enhanced carrier lifetime 2.
Formamidinium-based planar heterojunction photovoltaic devices fabricated using this method demonstrated an efficiency of Research at NREL has shown that perovskite photovoltaic devices may operate via the bulk photovoltaic effect, whereby charge carriers are separated by an induced internal dipole, rather than a p-n junction. This allows for open-circuit voltages in excess of the perovskite bandgap and could enable radically new perovskite device architectures.
The process can be applied with different perovskite compositions and solvents, thus making it a versatile new method for preparing high-quality perovskite films with superior improvements to stability. These patents consist of techniques and processes that enable rapid, inexpensive deposition of high-quality perovskite films.
These inventions allow perovskite photovoltaics to be manufactured consistently and cost-effectively in an industrial environment. This invention relates to one- and two-step methods for the solution growth of methylammonium lead halide e.
This opens the door for consistent, reliable, roll-to-roll-based deposition of perovskite films using an anti-solvent approach. Moreover, these methods improve both the open-circuit voltage and the short-circuit current density of perovskite films and enhance crystal growth.
Realizing practical applications of perovskite-based photovoltaic devices will likely require large-area perovskite solar modules that integrate multiple sub-cells.
A major difference between small-area cells and large-area modules is the lack of interconnecting contacts between individual sub-cells. Because a module always consists of multiple interconnected sub-cells, and a large photocurrent is concentrated at the relatively narrow interconnections, the interface behavior at the interconnections becomes critically important to the performance of the module.
This invention relates to methods for depositing and scribing large-area perovskite modules. By use of these techniques, a highly-efficient mixed-cation mini-module has been demonstrated with a power conversion efficiency of This corresponds to an active area module conversion of Recent work at NREL has shown that, over time, perovskite precursor inks using a DMF solvent degrade, resulting in a number of undesirable side products that may be subsequently incorporated into the deposited perovskite film.
For instance, perovskite films deposited from a precursor ink on Day 1 achieved an Storage of perovskite precursor materials is critical to industrial deposition processes, which may use large amounts of precursor material. This technology describes solutions that enable storage of perovskite precursors for up to 31 days without any signs of degraded film performance.
Researchers at NREL have developed a method to manufacture perovskite photovoltaic devices that allows the top and bottom sections of a device to be fabricated independently. This method enables new device architectures including those using perovskite heterojunctions and may improve overall device stability and performance. It can also be performed at low pressures, making it suitable for high-volume roll-to-roll manufacturing. These patents consist of alternative thin film and quantum dot chemistries to the common methylammonium lead halide CH 3 NH 3 PbI 3 perovskite devices.
These alternative compositions include novel organic, inorganic, and hybrid compositions for cations in the ABX 3 perovskite crystalline structure and have been shown to improve the performance of perovskite films by demonstrating both increased stability and efficiency. Although most research has been centered around methylammonium lead halide perovskites e. Unfortunately, the morphology of FA-perovskites is much more difficult to control, making growth of FA-perovskites challenging.
The invention here is a simple, effective method of performing a cation-exchange reaction on as-deposited films to change an MA-based perovskite film to an FA-based film while retaining the morphological character of the film. In this way, the benefits of MA-perovskite growth are retained for FA-based films. This invention relates to synthesis of optoelectronic devices using quantum dots composed of inorganic CsPbI 3 perovskite materials.
Photovoltaic devices produced from this approach have the highest power conversion efficiency and stabilized power output of any all-inorganic perovskite absorber, produce 1. The open-circuit voltage of 1. Based on their performance, CsPbI 3 quantum dot films produced in this fashion may be desirable for both LEDs or as the high-bandgap cell in a tandem photovoltaic device.
Generally, the oil growth reservoirs can include an algae growth control means for achieving both autotrophic growth and heterotrophic growth.
The algae growth control means can include a stress induction mechanism for controlling available light and nutrient levels to the algae growth reservoir.
An alternative embodiment can further include the addition of materials, which will initiate and induce the production of oils or starches directly. For example, a single algae growth reservoir can be subjected to a controllable light environment by retractable coverings, reversibly opaque coverings, or the like.
Alternatively, the algae growth control means can include providing separate autotrophic growth reservoirs and heterotrophic growth reservoirs within the algae growth reservoirs which are operatively connected to one another and configured for autotrophic growth and heterotrophic growth, respectively.
Although a staged process can be used, a combined growth process can be preferred under some circumstances. For example, the autotrophic growth and heterotrophic growth can be performed substantially simultaneously or overlapping.
Strains of algae. Lipid or oil-producing algae can include a wide variety of algae, although not all algae produce sufficient oil, as mentioned above. The most common oil-producing algae can generally include, or consist essentially of, the diatoms bacillariophytes , green algae chlorophytes , blue-green algae cyanophytes , and golden-brown algae chrysophytes.
In addition a fifth group known as haptophytes may be used. Specific non-limiting examples of bacillariophytes capable of oil production include the genera Amphipleura, Amphora, Chaetoceros, Cyclotella, Cymbella, Fragilaria, Hantzschia, Navicula, Nitzschia, Phaeodactylum, and Thalassiosira. Specific non-limiting examples of chlorophytes capable of oil production include Ankistrodesmus, Botryococcus, Chlorella,. In one aspect, the chlorophytes can be Chlorella or Dunaliella.
Specific non-limiting examples of cyanophytes capable of oil production include Oscillatoria and Synechococcus. A specific example of chrysophytes capable of oil production includes Boekelovia. Specific non-limiting examples of haptophytes include Isochrysis and Pleurochrysis. Such strains would certainly be useful in connection with the present invention. Optimal heterotrophic growth times can vary depending on the strain of algae and other operating parameters.
This can involve a balance of oil production, feed costs, and diminishing returns of oil percentage increases. As a general guideline, heterotrophic growth times can range from 2 days to 2 weeks, and are often from about 4 to 7 days. At longer times, foreign algae, bacteria and other factors can make maintaining acceptable growth conditions progressively more difficult. Further, the oil-producing algae of the present invention can include a combination of an effective amount of two or more strains in order to maximize benefits from each strain.
However, when discussed herein, the oil-producing algae is intended to cover intentionally introduced strains of algae, while foreign strains are preferably minimized and kept below an amount which would detrimentally affect yields of desired oil-producing algae and algal oil. For example, careful control of the growth environment can reduce introduction of foreign strains. An appropriate virus can be readily identified using conventional techniques. For example, a sample of the foreign algae will most often include small amounts of a virus which targets the foreign algae.
This virus can be isolated and grown in order to produce amounts which would effectively control or eliminate the foreign algae population among the more desirable oil-producing algae. During autotrophic growth, nutrients can be supplied to the oil-producing algae.
In one particular aspect, a nitrogen-fixing algae can be introduced to the oil-producing algae to supply nitrogen as a nutrient. The nitrogen-fixing algae 8 of FIG. In one embodiment, the nitrogen-fixing algae can include, or consist essentially of, cyanobacteria, i.
In another embodiment, the oil-producing algae may itself be cyanobacteria, which can then fix its own nitrogen, thereby reducing costs for the oil-producing growth. Process to select strains of algae for optimal growth and oil production.
To achieve optimal oil production, three steps can be applied. The first is the selection of species of algae with desirable characteristics of growth, robustness, and high lipid production.
The second is the identification of metabolic pathways involved in triggering and increasing lipid production, and the third is the application of mechanisms to affect these metabolic pathways. Balance of Oil-Production vs.
Cellulose or Starch Production While the process of the present invention can produce both biodiesel and bioethanol, it is optimized for the production of biodiesel. Biodiesel production is preferable for several reasons, the first of which is the higher efficiency and likely evolution of a diesel-based transportation fleet. The second reason is that the production of energy in the form of oil lipids by algae is more useful than the production of starch. If equal volumes of oil and starch are produced, the oil will contain significantly more energy.
Third, in the production of sugars from starch, not all the starch is saccharified into sugars which can be easily fermented, so a portion may be lost as unused sugars.
The final reason is that the production of biodiesel from the algal oil is essentially energy- neutral, so nearly all of the energy content of the algal oil is retained in the biodiesel. In contrast, the production of alcohol from biomass or starch is less efficient, especially during the fermentation stage which converts the sugars derived from the biomass or starch into alcohol. Fermentation is exothermic, with heat being generated that must be removed and often wasted.
In addition, one half of the carbon in the sugar is released during fermentation as carbon dioxide and is therefore not available for fuel energy. For all of these reasons biodiesel production is more efficient overall than bioethanol production and therefore the goal of highest efficiency and lowest cost is served by maximizing biodiesel production.
Nevertheless, starch-producing or biomass producing algae are one important aspect of the present invention, as described below in more detail. Such algal biomass can be the same or different algae strains than those used as the oil-producing algae.
If the starch or biomass growth is greater than needed, the excess can be converted to ethanol and sold profitably as a second product in addition to biodiesel. Carbon dioxide released during fermentation can be fed back into the algal growth stage, substantially eliminating at least this form of energy loss in the fermentation process. Recovery of Oil, Starch and Sugar from the Algae. Algae store oil inside the cell body, sometimes but not always in vesicles.
Oil can be extracted in extraction sub-system The extraction sub-system can include an oil extraction bioreactor 14 operatively connected to the algae growth reservoirs 6, 2. Within the oil extraction bioreactor the cell walls and algal oil vesicles of the oil-producing algae can be biologically ruptured to yield an algal oil and algal residue. A biological agent source 12 can be operatively connected to the oil extraction bioreactor.
The processes of the present invention can generally use at least one of three types of biological agents to release algae energy stores, i. A cellulase is an enzyme that breaks down cellulose, especially in the wall structures, and a cellulosome is an array or sequence of enzymes or cellulases which is more effective and faster than a single enzyme or cellulase.
Cellulases used for this purpose may be derived from fungi, bacteria, or yeast. Non- limiting examples of each include cellulase produced by fungus Trichoderma reesei and many genetic variations of this fungus, cellulase produced by bacteria genus Cellulomonas, and cellulase produced by yeast genus Trichosporon. A glycoproteinase provides the same function as a cellulase, but is more effective on the cell walls of microalgae, many of which have a structure more dependent on glycoproteins than cellulose.
In addition, a large number of viruses exist which invade and rupture algae cells, and can thereby release the contents of the cell — in particular stored oil or starch.
Such viruses are an integral part of the algal ecosystem, and many of the viruses are specific to a single type of algae. The particular virus selected will depend on the particular species of algae to be used in the growth process. One aspect of the present invention is the use of such a virus to rupture the algae so that oil or starch contained inside the algae cell wall can be recovered.
Mechanical crushing, for example, an expeller or press, a hexane or butane solvent recovery step, supercritical fluid extraction, or the like can also be useful in extracting the oil from oil vesicles of the oil-producing algae. Regardless of the particular biological agent or agents chosen such can be introduced in amounts which are sufficient to serve as the primary mechanism by which algal oil is released from oil vesicles in the oil-producing algae, i. Once the oil has been released from the algae it can be recovered or separated 16 from a slurry of algae debris material, e.
This can be done by sedimentation or centrifugation, with centrifugation generally being faster. Starch production can follow similar separation processes. Recovered algal oil 18 can be collected and directed to a conversion process 50 as described in more detail below. The algal biomass 22 left after the oil is separated may be fed into the depolymerization stage described below to recover any residual energy by conversion to sugars, and the remaining husks can be either burned for process heat 62 or sold as an animal food supplement or fish food.
Conversion of Starch and Cellulose to Sugar Depolymerization or Saccharification An algal feed can be formed from a biomass feed source as well as an algal feed source. Biomass from either algal or terrestrial sources can be depolymerized in a variety of ways such as, but not limited to saccharification, hydrolysis or the like.
The source material can be almost any sufficiently voluminous cellulose, lignocellulose, polysaccharide or carbohydrate, glycoprotein, or other material making up the cell wall of the source material. Suitable algal feed can be prepared in feed production sub-system In one aspect of the present invention, the algal feed can be provided by cultivating algae 26, including supplying any nutrients 28, and extracting the algal feed therefrom after depolymerization.
Alternatively, or in combination, the algal feed can be provided by cultivating a non-algal biomass 24 and extracting the algal feed therefrom. Algae can be cultivated on-site and other terrestrial biomass can transported from exterior sources or growers. Preferably, at least some of the biomass can be cultivated on-site in order to reduce transportation costs.
Suitable non-algal biomass can include any starch or cellulosic material such as, but in no way limited to, corn, sugarcane, switchgrass, miscanthus, grasses, grains, grass residues, grain residues, poplar or willow trees, other trees, tree residues, bio-refuse, mixtures of these materials, and the like.
In one embodiment of the invention, non-algal biomass can be the only input source for sugar production, and algae in the oil-production sub-system 10 essentially becomes a bioreactor to produce biodiesel from generic biomass.
In effect, the algae in oil-production sub- system 10 becomes a conversion vehicle which converts feed sugar formed from generic biomass into algal oil which can then be converted to biodiesel as described below. A feed biomass source, whether algal biomass 26, non-algal biomass 24, or a combination of the two, can be operatively connected to a depolymerizing reactor The reactor can be configured for forming sugars from the feed biomass source by providing suitable operating conditions.
In the present invention, one approach is to use biological enzymes to depolymerize break down the biomass into sugars or other simple molecular structures which can be used as feed for the oil-producing algae.
A feed separator 34 can be operatively connected to the depolymerizing reactor and the algae growth reservoirs. The feed separator can direct at least a portion of the algal feed to the algae growth reservoirs 6 as a feed for the dark or heterotrophic stage of the oil-producing algae in cultivation sub-system The fermentation stage can be conventional in its use of yeast to ferment sugar to alcohol. The fermentation process produces carbon dioxide, alcohol, and algal husks. All of these products can be used elsewhere in the process and systems of the present invention, with substantially no unused material or wasted heat.
Alternatively, if ethanol is so produced, it can be sold as a product or used to produce ethyl acetate for the transesterification process.
Similar considerations would apply to alcohols other than ethanol. In one preferred aspect, both ethanol and ethyl acetate can be formed using separate fermentation reactors. For example, ethanol can be formed in a first reactor 37 and at least a portion of the ethanol can be reacted with acetic acid from a second reactor 36 to form ethyl acetate in a third reactor The ethyl acetate can generally be formed in the presence of other compounds and components such as, but not necessarily included with or limited to, water, ethanol, acetic acid, etc.
The carbon dioxide 46 can be captured and returned to either the light 2 or dark stage 6 of the oil-producing algae cultivation step as a carbon source to increase production of oil.
A suitable CO 2 recycle line or other system can be used to direct the carbon dioxide accordingly. At least a portion of ethanol or ethyl acetate product 44 can be used in the conversion of the algal oil to biodiesel via transesterification sub-system Any excess ethanol 48 can be stored after distillation and sold as bioethanol.
If other alcohols, e. Algal oil can be converted to biodiesel through a process of direct hydrogenation or transesterification of the algal oil. Algal oil is in a similar form as most vegetable oils, which are in the form of triglycerides. A triglyceride consists of three fatty acid chains, one attached to each of the three carbon atoms in a glycerol backbone. This form of oil can be burned directly. However, the properties of the oil in this form are not ideal for use in a diesel engine, and without modification, the engine will soon run poorly or fail.
In accordance with the present invention, the triglyceride is converted into biodiesel, which is similar to but superior to petroleum diesel fuel in many respects. One process for converting the triglyceride to biodiesel is transesterification, and includes reacting the triglyceride with alcohol or other acyl acceptor to produce free fatty acid esters and glycerol.
The free fatty acids are in the form of fatty acid alkyl esters. A transesterification reactor 52 of transesterification sub-system 50 can be operatively connected to the oil extraction bioreactor of extraction sub-system 20 to convert at least a portion of the algal oil to biodiesel. The biological process uses an enzyme known as a lipase 54 to catalyze the transesterification, while the chemical process uses a synthetic catalyst 54 which may be either an acid or a base.
The lipase- catalyzed reaction is preferable because it involves no harsh chemicals and produces a high-quality product in the simplest way. Further, the use of ethyl acetate can be preferred over ethanol or other alcohol in transesterification since alcohol can be excessively damaging to enzyme activity. As such, in one embodiment of the present invention, transesterifying can include introducing an enzyme for converting the algal oil to biodiesel. Non-limiting examples of suitable lipase may include, but are not limited to, those from Rhizomucor miehei, Thermomyces lanuginose, Pseudomonas fragi, and Candida cylindracea, and those described in U.
Patent Nos. With the chemical process, additional steps are needed to separate the catalyst and clean the fatty acids. In addition, if ethanol is used as the acyl acceptor, it must be essentially dry to prevent production of soap via saponification in the process, and the glycerol must be purified. The biological process, by comparison, can accept ethanol in a less dry state and the cleaning and purification of the biodiesel and glycerol are much easier. Either or both of the biological and chemically-catalyzed approaches can be useful in connection with the processes of the present invention.
Transesterification often uses a simple alcohol, typically methanol derived from petroleum. However, ethanol can also be used as the alcohol in transesterification, in which case the biodiesel is fatty acid ethyl ester FAEE. Direct hydrogenation can also be utilized to convert at least a portion of the algal oil to a biodiesel. As such, in one aspect, the biodiesel product can include an alkane. The process of the present invention focuses on the use of ethanol or ethyl acetate for transesterification because both substances can be readily produced as part of the fermentation sub-system 40 rather than from external sources.
This further lowers cost because the ethanol or ethyl acetate can be derived from plant material rather than from fossil sources. The ethanol may be used directly as the alcohol or may be converted first to ethyl acetate to extend the longevity of the lipase enzyme, if used. Glycerol produced in transesterification 60 may be used as a drying agent to dry the ethanol 56 for transesterification, and may also be sold 60 as a product. To be used as a drying agent, the glycerol can be first purified and dried.
Pure dry glycerol is a chemical drying agent because it attracts and holds water. The ethanol produced from the fermentation described above is preferably essentially dry anhydrous to be used in chemical transesterification. Thus, a distillation device can be operatively connected between the fermentation separator and the transesterification reactor. The remaining water can be removed chemically, and the dry glycerol produced from transesterification can be used as the drying agent.
The algal triglyceride can also be converted to biodiesel by direct hydrogenation. In this process, the products are alkane chains, propane, and water. The glycerol backbone is hydrogenated to propane, so there is substantially no glycerol produced as a byproduct.
Furthermore, no alcohol or transesterification catalysts are needed. All of the biomass can be used as feed for the oil-producing algae with none needed for fermentation to produce alcohol for transesterification. The resulting alkanes are pure hydrocarbons, with no oxygen, so the biodiesel produced in this way has a slightly higher energy content than the alkyl esters, degrades more slowly, does not attract water, and has other desirable chemical properties.
Final Products The final products from the processes presented herein are large amounts or proportions of biodiesel 58 and possibly lesser amounts or proportions of bioethanol 48 resulting from any excess production not used for biodiesel.
If direct hydrogenation is used, then no alcohol will be produced. If transesterification is used, glycerol is produced and may be sold as a byproduct.
In addition, the process of the present invention can be highly efficient and energy-positive, meaning the energy produced in the form of fuels is far in excess of external input energy, because very little fossil energy is used.
Algae growth requires none of the heavy machinery, expensive fuels, or chemical fertilizers and pesticides required by conventional agriculture. Further, the algae can be processed near the growth ponds, eliminating transportation costs. Comparison of biodiesel to petroleum diesel. Following is a discussion of some of the qualities and advantages of biodiesel compared to petroleum diesel.
Biodiesel formed in accordance with the present invention is atmospherically carbon-neutral. Algal oil contains little or no sulfur, so production of biodiesel using the present invention reduces sulfur emissions, even compared to ultra low sulfur petroleum diesel. Biodiesel burns more efficiently which results in a smoother-running engine. The equivalent cetane number of biodiesel is higher than petroleum diesel, reducing diesel noise and knock.
The alkyl esters or alkanes in biodiesel contain chains with none of the ring structures found in petroleum diesel. These petroleum ring structures or aromatic hydrocarbons give diesel fuel and diesel exhaust its characteristic smell.
The smell of biodiesel fuel and biodiesel exhaust is cleaner and lacks most of the familiar diesel aroma. Biodiesel also has a higher flash point near 0 C compared to petroleum diesel at 70 0 C, so it is safer to store and handle. Biodiesel breaks down about four times faster in the environment, so spills are less enduring. Biodiesel has higher lubricity so fuel injection systems and other engine components can have a longer life.
Importantly, conventional diesel engines do not need to be modified to use biodiesel.
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