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Topic Review
Bioethanol Processing
The liquid biofuel bioethanol is extensively produced worldwide through the fermentation of sugars obtained from various raw materials, including lignocellulosic biomass, an abundant renewable resource. Due to its recalcitrant nature, lignocellulosic materials typically is pretreated using mechanical, chemical, physicochemical, or biological methods to enhance sugar recovery. The pretreated lignocellulosic biomass then undergoes a fermentation process, either sequentially or simultaneously with saccharification, resulting in the biofuel called second-generation ethanol. The ethanol yield is influenced by various fermentation strategies and conditions, such as inoculum concentration, medium agitation, temperature, and pH.
  • 122
  • 26 Jan 2024
Topic Review
Bioethanol Production of Distillery Stillage
Distillery stillage has a high energy potential (13.6 MJ/kg TS, 10.4 MJ/kg COD), which indicates that it can be processed via anaerobic digestion and is a suitable substrate for conversion into energy.
  • 1.3K
  • 16 Nov 2021
Topic Review
Biofuel
A biofuel is a fuel that is produced through contemporary processes from biomass, rather than a fuel produced by the very slow geological processes involved in the formation of fossil fuels, such as oil. Since biomass technically can be used as a fuel directly (e.g. wood logs), some people use the terms biomass and biofuel interchangeably. More often than not, however, the word biomass simply denotes the biological raw material the fuel is made of, or some form of thermally/chemically altered solid end product, like torrefied pellets or briquettes. The word biofuel is usually reserved for liquid or gaseous fuels, used for transportation. The U.S. Energy Information Administration (EIA) follows this naming practice. If the biomass used in the production of biofuel can regrow quickly, the fuel is generally considered to be a form of renewable energy. Biofuels can be produced from plants (i.e. energy crops), or from agricultural, commercial, domestic, and/or industrial wastes (if the waste has a biological origin). Renewable biofuels generally involve contemporary carbon fixation, such as those that occur in plants or microalgae through the process of photosynthesis. Some argue that biofuel can be carbon-neutral because all biomass crops sequester carbon to a certain extent – basically all crops move CO2 from above-ground circulation to below-ground storage in the roots and the surrounding soil. For instance, McCalmont et al. found below-ground carbon accumulation ranging from 0.42 to 3.8 tonnes per hectare per year for soils below Miscanthus x giganteus energy crops, with a mean accumulation rate of 1.84 tonne (0.74 tonnes per acre per year), or 20% of total harvested carbon per year. However, the simple proposal that biofuel is carbon-neutral almost by definition has been superseded by the more nuanced proposal that for a particular biofuel project to be carbon neutral, the total carbon sequestered by the energy crop's root system must compensate for all the above-ground emissions (related to this particular biofuel project). This includes any emissions caused by direct or indirect land use change. Many first generation biofuel projects are not carbon neutral given these demands. Some have even higher total GHG emissions than some fossil based alternatives. Some are carbon neutral or even negative, though, especially perennial crops. The amount of carbon sequestrated and the amount of GHG (greenhouse gases) emitted will determine if the total GHG life cycle cost of a biofuel project is positive, neutral or negative. A carbon negative life cycle is possible if the total below-ground carbon accumulation more than compensates for the total life-cycle GHG emissions above ground. In other words, to achieve carbon neutrality yields should be high and emissions should be low. High-yielding energy crops are thus prime candidates for carbon neutrality. The graphic on the right displays two CO2 negative Miscanthus x giganteus production pathways, represented in gram CO2-equivalents per megajoule. The yellow diamonds represent mean values. Further, successful sequestration is dependent on planting sites, as the best soils for sequestration are those that are currently low in carbon. The varied results displayed in the graph highlights this fact. For the UK, successful sequestration is expected for arable land over most of England and Wales, with unsuccessful sequestration expected in parts of Scotland, due to already carbon rich soils (existing woodland) plus lower yields. Soils already rich in carbon includes peatland and mature forest. Grassland can also be carbon rich, and Milner et al. argue that the most successful carbon sequestration in the UK takes place below improved grasslands. The bottom graphic displays the estimated yield necessary to compensate for related lifecycle GHG-emissions. The higher the yield, the more likely CO2 negativity becomes. The two most common types of biofuel are bioethanol and biodiesel. Bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as corn, sugarcane, or sweet sorghum. Cellulosic biomass, derived from non-food sources, such as trees and grasses, is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form (E100), but it is usually used as a gasoline additive to increase octane and improve vehicle emissions. Bioethanol is widely used in the United States and in Brazil. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe. It can be used as a fuel for vehicles in its pure form (B100), but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles. In 2018, worldwide biofuel production reached 152 billion liters (40 billion gallons US), up 7% from 2017, and biofuels provided 3% of the world's fuels for road transport. The International Energy Agency want biofuels to meet more than a quarter of world demand for transportation fuels by 2050, in order to reduce dependency on petroleum. However, the production and consumption of biofuels are not on track to meet the IEA's sustainable development scenario. From 2020 to 2030 global biofuel output has to increase by 10% each year to reach IEA's goal. Only 3% growth annually is expected. Here are some various social, economic, environmental and technical issues relating to biofuels production and use, which have been debated in the popular media and scientific journals.
  • 1.2K
  • 12 Oct 2022
Topic Review
Biofuel production from different sources
Due to the depletion of fossil fuels, biofuel production from renewable sources has gainedinterest. Malaysia, as a tropical country with huge resources, has a high potential to produce differenttypes of biofuels from renewable sources. In Malaysia, biofuels can be produced from various sources,such as lignocellulosic biomass, palm oil residues, and municipal wastes. Besides, biofuels are dividedinto two main categories, called liquid (bioethanol and biodiesel) and gaseous (biohydrogen andbiogas). Malaysia agreed to reduce its greenhouse gas (GHG) emissions by 45% by 2030 as theysigned the Paris agreement in 2016. Therefore, we reviewed the status and potential of Malaysia asone of the main biofuel producers in the world in recent years. The role of government and existingpolicies have been discussed to analyze the outlook of the biofuel industries in Malaysia.
  • 2.3K
  • 27 Oct 2020
Topic Review
Biofuel Supply Chain
Bioenergy is one of the alternatives to secure energy demand, despite increasing debate on the sustainability of using bioenergy as a renewable source. As the source is disseminated over a large area and affected by seasonality, the potential benefit is highly dependent on other cost and benefit trade-offs along the supply chain.
  • 2.7K
  • 28 Oct 2020
Topic Review
Biofuel Vehicles
Biofuels and bioenergy are produced by processing biomass, or organic matter, from plants, crops, and their waste products. Biofuel can displace fuels made from petroleum because it comes from renewable sources. The only alternative energy source that can provide liquid fuels to take the place of fossil fuels is bioenergy. Biofuels are a viable alternative to meet future demand while reducing greenhouse gas emissions and environmental effects.
  • 615
  • 18 Mar 2024
Topic Review
Biofuels
As defined by the European Union, “Biofuels are liquid or gaseous transport fuels such as biodiesel and bioethanol which are made from biomass”. Bioethanol is the most common biofuel obtained by a fermentation process and can be run by using a variety of carbon sources.
  • 801
  • 16 Feb 2021
Topic Review
Biofuels for Internal Combustion Engine
Biofuel, a cost-effective, safe, and environmentally benign fuel produced from renewable sources, has been accepted as a sustainable replacement and a panacea for the damaging effects of the exploration for and consumption of fossil-based fuels.
  • 2.4K
  • 28 Sep 2021
Topic Review
Biofuels for Spark Ignition Engines
Biofuels are receiving increased scientific attention, and recently different biofuels have been proposed for spark ignition engines. Different biofuels, mainly ethanol, methanol, i-butanol-n-butanol, and acetone, are blended together in single dual issues and evaluated as renewables for SIE. Each blend showed some advantaged and drawbacks in terms of emissions and performance. 
  • 841
  • 17 Mar 2021
Topic Review
Biofunctionalization of the Tissue Engineered Heart Valves
Valve replacement is the mainstay of treatment for end-stage valvular heart disease, but varying degrees of defects exist in clinically applied valve implants. A mechanical heart valve requires long-term anti-coagulation, but the formation of blood clots is still inevitable. A biological heart valve eventually decays following calcification due to glutaraldehyde cross-linking toxicity and a lack of regenerative capacity. The goal of tissue-engineered heart valves is to replace normal heart valves and overcome the shortcomings of heart valve replacement commonly used in clinical practice. Surface biofunctionalization has been widely used in various fields of research to achieve functionalization and optimize mechanical properties.
  • 489
  • 28 Sep 2022
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