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https://en.wikipedia.org/w/index.php?title=Biorefinery

A Biorefinery is a facility that processes raw biomass to produce an assortment of new consumable commercial products. The various processes used in biorefinery stems from research and technologies used in various fields, including but not limited to bioengineering, agriculture, chemistry, forestry, environmental science and food science. .

The biorefinery industry can be simplified into two categories: energy production and chemical or material production. Energy production aims to produces fuels, heat, and energy. Chemical/material production mainly produces commercial bio-based products such as solvents, adhesives, and surfactants. In either case, byproducts from the main production are used to further increase the efficiency and profitability of each industy.

Sourcing of biomass:
The sourcing of materials for biorefineries can be divided into two categories: biomass refinery, and waste-utilization refinery. Biomass refinery uses raw biomass, typically grown and harvested through commercial agriculture, whereas waste-utilization refinery uses waste bio-materials that would otherwise have been discarded in landfills or used in compost. The collective term for the materials from either source, is feedstock.

Methods of biorefinery
The majority of the mass of biomass is lignocellulosic material, which compose plant walls and accounts for most of a plant’s rigidity. Lignocellulose is made of three major components, hemicellulose, cellulose, and lignin. Much of the processes in biorefining aim to reduce these compounds into simpler sugars. Pretreatments of these materials, such as the physical milling and grinding are used to increase the efficiency of their conversion. Many of the processes of biorefining require some form of biochemical conversion, such as through the use of various acids, enzymes, and bacterium to breakdown the material. Thermochemical processes are also used, and may even be used in combination with biochemical means, especially for the conversion of lignocellulosic biomass.

The process for producing second generation fuels include the fermentation of simple sugars, or by a gasification process. Additionally, another method is derived from the thermochemical hydrolysis of plant cell walls, producing a mixture of carbon monoxide and hydrogen gases, known as synthesis gas. The various methods and processes of gasification heat the biomass in a range of thermal and atmospheric conditions, from as low as 300°C to 1500°C, and from atmospheric pressure to 30ATM.

Additionally, second generation biofuels can also be produced through fast-pyrolysis, turning the organic material into pyrolysis oil (bio-crude), which can be further processed into usable fuel. The fast-pyrolysis method breaks down the polymer chains in organic compounds in a high-temperature, zero oxygen environment. The term “fast-pyrolysis” is noted because of its use of moderate conversion temperatures, typically reaching 500°C, and held for a brief duration of two to three seconds, wherein the cracking of emitted vapors into gases is minimized. The vapors and gases from this heating are then rapidly cooled, mainly into condensed bio-crude oil.

Biorefinery products
Biofuels represent the majority of biorefinery production. The most commercially available liquid fuel products of biorefinery is ethanol, which is used in ethanol-blended fuels for motor vehicles. The United States and Brazil are major producers of ethanol fuel, refined from corn and sugarcane respectively. Ethanol biofuel made from these materials are referred to as first generation biofuels. “Green” diesel fuels made from second generation syngas fuels are being proposed for use in Europe.4 Hydrocarbon fuels that use plant lignin are also being researched as a viable fuel source. Research is being conducted to further refine bio-crude, oils obtained from biorefining, into possible substitues of petroleum fuels

Additionally, bioproducts such as adhesives, surfactants, solvents, dielectric fluids, lubricants, plastics, and papers are made and have become commercially available. Typically, these forms of goods are considered as value-added products.

Biorefinery is also used to extract phytochemicals from various plants, which can be used for scientific research on an industrial scale. Phytochemicals are difficult to extract from plants, such as corn. Biorefinery allow the extraction of phytochemcials with higher efficiency compared to conventional means, allowing researchers to conduct more research on the effects of phytochemicals consumption in relation to health.

Environmental impacts of biorefinery
In response to increasing energy demands, diminishing fossil fuel sources, and the surge of carbon emissions from fossil fuel consumption, biorefineries and their products offer a more eco-friendly solution to these issues.

One of the main points for the advocacy of biorefinery, is the reduction of carbon dioxide emissions through the use of biorefinery products in lieu of petroleum products. The burning of petroleum and fossil fuels is a direct and major contributor to carbon dioxide emissions, a greenhouse gas. Additionally, many plastics are derived from petroleum bi-products, and present a two-fold problem: most of these consumer plastics are non-biodegradable, becoming a pollution hazard when improperly disposed of, or contributes additional emissions when incinerated for disposal. Biorefineries, in comparison to oil refineries, recycle the carbon input and output, and can even reduce the net carbon-footprint, such as when unused biomass grown in fields is recycled for use as fertilizer and mitigating soil erosion. 5 From this standpoint, much of the products created from biorefining are considered as “carbon neutral,” since the majority of carbon that is consumed during their production comes from harvested biomass, which itself draws carbon from CO2 in the air to use for photosynthesis. Biorefineries are also cleaner, since they do not produce environmentally toxic waste water and oils, emissions, and compounds from oil refining. The development of green chemistry for use in biorefineries offers another avenue of approach to reduce the use and production of hazardous chemicals and their byproducts, such as metal-based oxidation agents and solvents used in traditional purification proceses.

However as of first quarter 2018,the biorefinery processes are not yet efficient enough to produce sufficient amounts of liquid fuels to meet global demand. In the United States alone, it is estimated that one billion dry tons of biomass materials would need to be converted to meet only 30% of liquid fuel demands. Roughly the same amount of biomass would need to be converted to supply 21% of the energy consumed by the US.

Additionally, waste-utilization refinery cuts down on the growth of landfills as it uses discarded biomass products such as wood, paper, food and animal wastes as the main material source of producing new products.

Emerging biorefinery technologies
Several emerging biorefinery processing technologies focus on the use of sustainable-only materials.


 * Ionic liquids (ILs) are groups of salts that maintain a liquid phase at room temperature. ILs offer an extremely low vapor pressure that is advantageous in its use as a solvent, such as reducing the amount of volatile compounds during catalysis. Additionally, ILs are flexible with an estimated 1018 possible combinations, offering customized physical properties such as melting point, density, viscosity, acidity, and solubility, to suit a particular application. The use of ILs in biorefineries could offer a “green” solvent for the conversion of cellulose and lignocellulose material.


 * Super critical CO2 offers the possibility of a benign medium in biorefinery uses. CO2 reaches its supercritical fluid (SCF) state at pressures above 72.8 bar (7.3MPa) and temperatures exceeding 304K (31°C). At this liquid state, the properties of CO2 such as the dielectric constant, refraction index, and solubility, can be tuned by changes in pressure and temperature. This tunability make it candidate for many applications as a solvent and extraction medium, as it is easily removed. Additionally, supercritical CO2 offers several advantages as a solvent for consumer product, being that it is nonflammable, nontoxic, odorless and tasteless.