First generation biofuels
They are those that come from or are made using sugar, starch or vegetable oil, which are contained in countless materials such as: sugar cane juice, corn grains, beet or beet juice, sunflower seed oil, soybean oil, palm oil, castor oil, cotton seed oil, coconut oil, peanut oil, among others. Animal fats, fats and waste oils from cooking and food processing are also used as inputs.[10].
These types of biofuels are produced using conventional technology such as fermentation (for sugars and carbohydrates), transesterification (for oils and fats), and anaerobic digestion (for organic waste).
Among these are:
They are alcohols produced biologically by the action of microorganisms and enzymes through the fermentation of sugars or starches (easier), or cellulose (which is more difficult). Biobutanol (also called biogasoline) is declared as a direct replacement for gasoline, since it can be used directly in a gasoline engine (in a similar way to biodiesel with diesel engines). Ethanol fuel is the most common biofuel globally, particularly in Brazil. While the least common are propanol and butanol.
Alcohol fuels are produced by fermentation of sugars derived from wheat, corn, beets, cane, molasses and any sugar or starch from which alcoholic beverages can be made (such as potato and fruit waste, etc.). The ethanol production methods used are enzymatic digestion (for release of stored starch sugars), sugar fermentation, distillation and drying. The distillation process requires providing a large amount of energy.
Ethanol can be used in petroleum engines to replace gasoline, it can also be mixed with gasoline in any percentage. Many existing car engines (that use petroleum) can run and start with combinations of more than 15% bioethanol with petroleum/gasoline. Ethanol has a lower energy density than gasoline; This means that it takes more fuel (volume and mass) to produce the same amount of work. An advantage of ethanol (CH3CH2OH) is that it has a higher octane value than the ethanol-free gasoline available at roadside gas stations, allowing an increase in the engine's compression ratio to increase thermal efficiency. In high altitude locations (where the air is thin), some states require a blend of gasoline and ethanol as a winter oxidizer that reduces emissions of air pollutants. Ethanol, in turn, is also used as fuel for bioethanol fireplaces.
On the downside, dry ethanol has roughly one-third less energy per unit volume compared to gasoline. With current large, unsustainable and unscalable subsidies, ethanol fuel costs more per distance traveled than current high US gasoline prices.
Methanol is currently produced from natural gas, a non-renewable fossil fuel. But in turn they can be produced by biomass "Biomass (energy)") from bioethanol. The economy of methanol is an alternative to that of hydrogen, compared to the current production of hydrogen by natural gas.
Butanol (C4H9OH) is generated by ABE (acetone, butanol, ethanol) fermentation and experimental modifications of the process show great potential for net energy gained with butanol as the only liquid product. This would produce more energy and supposedly can be burned “directly” in existing gasoline engines (without having to modify the engine or car), and is less corrosive and water-soluble than ethanol. In turn, it can be distributed through current infrastructures. DuPont and BP are working together to help develop butanol. Traces of Escherichia coli have also been successfully engineered to produce butanol by intercepting amino acids from their metabolisms.
It is the most common biofuel in Europe. This is a liquid biofuel composed of alkyl esters of short-chain alcohols such as ethanol and methanol, with long-chain fatty acids obtained from renewable biomass: vegetable oils, animal fats or microalgae oil.[11] Its main raw materials include vegetable oils such as: soybean, jatropha, rapeseed, mahua, mustard, flax, sunflower, palm oil, hemp, algae, among others. Pure biodiesel (B100) is the lowest emission diesel fuel.
Biodiesel can be used in any diesel engine when mixed with mineral diesel. In some countries, manufacturing companies build their diesel engines under the guarantee that they can use B100. In many European countries, a 5% biodiesel blend is widely used and is available at thousands of gas stations. In addition, this is an oxygenated fuel, that is, it contains a reduced amount of carbon and a higher content of hydrogen and oxygen than fossil diesel. This improves the combustion of biodiesel and reduces particulate emissions from unburned carbon.
Biodiesel is also safe to handle and transport, as it is as biodegradable as sugar, one-tenth as toxic as table salt, and has a flash point of around 148°C (300°F) compared to diesel-based petroleum, which contains a flash point of 52°C (125°F).
In the United States, more than 80% of commercial trucks and city buses run on diesel. The emerging biodiesel market in the United States is estimated to grow 200% from 2004 to 2005. “By the end of 2006, there was an estimate that biodiesel production would grow four times as much (as of 2004) to more than 1 billion gallons ().”
Hydrobiodiesel is produced through the "biological hydrocracking" of oil raw materials, such as vegetable oils and animal fats. Hydrocracking is a refining method that uses elevated temperatures and pressures in the presence of a catalyst to break down large molecules, such as those found in vegetable oils, into small hydrocarbon chains used in diesel engines. Green diesel has the same chemical properties as diesel-based oil and does not require new engines, pipelines or infrastructure to be distributed and used. Although it has not yet been produced at competitive costs against petroleum, gasoline versions are still in development. Green diesel is being developed in Louisiana and Singapore by ConocoPhillips, Neste Oil, Balero, Dynamic Fuels, and Honeywell UOP.
A study led by Professor Lee Sang-yup at the Korea Advanced Institute of Science and Technology (KAIST) and published in the international scientific journal Nature used a genetically modified strain of Escherichia coli fed with glucose found in plants or other non-food crops to produce biogasoline with the enzymes produced. Enzymes converted the sugar into fatty acids and then converted them into hydrocarbons that were chemically and structurally identical to those found in commercial gasoline. That is, they managed to transform glucose into biofuel gasoline that does not need to be mixed.[12] Then in 2013, UCLA researchers designed a new metabolic pathway to avoid glycolysis and increase the conversion rate of sugar into biofuel. It is believed that in the future it will be possible to modify the genes (of E. Coli) to obtain gasoline from straw or animal manure.
These are high cost, but effective components that act as octane boosters. They also improve engine performance, while significantly reducing engine wear and exhaust toxic emissions. By greatly reducing the amount of ozone in the atmosphere, they thus contribute to improving air quality.
This is obtained from methane through the process of anaerobic digestion of organic matter by anaerobes. It can also be obtained from biodegradable waste or by the use of energy crops in anaerobic digesters to supply gas fields. The solid product, "digestate", can be used both as biofuel and fertilizers. Biogas can be recovered through a waste processing system (a biological-mechanical treatment). Farmers can produce biogas from their livestock manure through anaerobic digesters.
This is a mixture of carbon monoxide, hydrogen and other hydrocarbons, produced by the partial combustion of biomass "Biomass (energy)"), that is, combustion with an amount of oxygen that is not sufficient to convert the biomass completely into carbon dioxide and water. Before partial combustion, the biomass is dried, and sometimes polarized. The resulting gas mixture, syngas, is more efficient than direct combustion of the original biofuel; most of the energy contained in this fuel is extracted.
-Syngas can be burned directly in an internal combustion engine, turbines or in high temperature fuel cells.
-It can be used to produce methanol, DME, hydrogen, and as a substitute for diesel fuel (through the Fischer-Tropsch process). In turn, it can be used in a mixture of alcohols that can be mixed in gasoline.
Second generation biofuels (advanced)
These are produced by sustainable raw material. Sustainable matter is defined, among many, by its availability and its impact on greenhouse emissions and on biodiversity and land use. Its inputs are energy crops, that is, fast-growing non-food vegetables with a high density and amount of energy stored in their chemical components. Many of the second generation biofuels are still in development, such as cellulosic ethanol, algae fuel, biohydrogen, biomethanol, DMF, BioDME, Fischer-Tropsch process diesel, biohydrogen diesel, alcohol blends, wood diesel, among others.
Cellulosic ethanol production uses crops or non-edible product waste. Furthermore, it does not divert food from the animal or human food chain. Lignocellulose is a “woody” material structure of plants. This matter is abundant and diverse, and in some cases (such as citrus peels or sawdust) is itself a significant problem for disposal.
The production of ethanol from cellulose is a highly difficult technical problem to solve. In nature, ruminant feedstocks (such as cattle) eat grass and then use slow enzymatic digestive processes to break down glucose. In cellulose ethanol laboratories, several experimental processes are being developed to do the same process, so that the released sugars can be fermented to make ethanol fuel. The use of high temperatures has been identified as an important factor in increasing the global economic viability of the biofuels industry and the identification of enzymes that are stable and can be used efficiently at extreme temperatures is an active area of research.
The recent discovery of the fungus Glocladium roseum points towards the production of the so-called cellulose myco-diesel. These organisms (recently discovered in the tropical forests of northern Patagonia) have the unique ability to convert cellulose into medium-length hydrocarbons typically found in diesel fuel. Scientists are also working on the experimental design of the genetic recombination of the DNA of certain organisms that could increase their potential as biofuels.
Scientists working with the New Zealand company Lanzatech have developed a technology to use industrial gases, such as carbon monoxide, as a raw material to produce ethanol through a microbial fermentation process. In October 2011, Virgin Atlantic announced it was teaming up with Lanzatech to run a demonstration plant in Shanghai that would produce an aviation fuel from waste gases from steel production.
The monitoring of vertically integrated industries in the biodiesel sector has shown how they have been improving in the production of more complex food products as well as specializing in the requirements of different markets. The increase in the price of these new products has allowed them to survive and grow in this complex globalized world, especially those companies that are located far from the traditional export ports.[13] In the case of the new corn bioethanol plants, the strategy has been to multiply energy sources and integrate different technologies such as the use of waste and energy crops with biodigesters generating streams of gas, electricity and heat that can optimize the processes. An example of this can be seen in Rio Cuarto "Río Cuarto (city)") with the integration between bioelectric companies dedicated to biogas and Bio4, producer of burlanda and bioethanol.[14].