Biorefinery is a broad term referring to the conversion of a wide range of different biobased feedstocks to a wide range of products, including food, feed, chemicals, materials, and energy (fuels, energy and heat). The feedstock can include trees, energy crops such as switchgrass, agricultural products such as grain and waste products such as municipal waste. A biorefinery may be a single processing plant or a cluster of facilities (which may or may not be on the same site) which are integrated together. It may use one feedstock or many and may use biochemical conversion, thermochemical conversion or a combination of the two.
Biorefineries exploit all of the elements of biomass, recycling secondary products and wastes of the reaction into valuable products, even producing the very energy which powers the process itself. In this respect, the concept is analogous to a petroleum refinery, where oil is refined into many marketable products including chemicals, energy and fuels. However there is a crucial difference: biorefineries are based on the use of renewable materials as a feedstock whereas today’s petroleum refineries are based on the use of non-renewable materials such as fossil fuels.
The use of all components of the biomass has a positive impact on both economics and the environment. Typically, a mix of high-value, low-volume products (such as fuels and energy) and low-value, high-volume products (cosmetics and nutraceuticals) are produced in a biorefinery. The high-value products enhance profitability, the low-value products provide scale and the use of energy from the process itself reduces the Greenhouse Gas (GHG) impact of the facility.
Source: Bridge 2020
Biorefining has been a common practice among many traditional biomass industries for many years. In the paper industry for example, wood is converted to a pulp, which is then converted to paper pulp (39%), chemicals such as xylose, acetic acid and furfural (11%), black liquor (50%) and exportable energy. In the wheat to ethanol industry, the wheat is converted to ethanol (33%), grain residues (when dried these are known as Distillers Dried Grains with Solubles – a livestock feed) and CO2 (generally captured and re-used to carbonate soda drinks) in approximately equal proportions. In the sugar industry, a whole range of different products, of varying market size and value, are produced, depending upon the plant in question. They can be as varied as food grade sugar, ethanol, beet pulp for animal feed, high value chemicals such as betaine and raffinates and even topsoil and stones from beet processing!
A wide range of more advanced biorefining techniques are under development, including the production of jet fuels and energy from domestic waste and the biorefining of algae to produce high value chemicals, energy and fuel products. Ultimately, the range of products available through biorefining will depend upon the availability of different feedstocks and the market value (and need) for different products. It may also vary over time as market conditions vary, and when new technologies are developed.
Industrial biorefineries have been identified as the most promising route to the creation of a new domestic biobased industry in Europe. Industrial biotechnology provides one crucial way by which biomass can be converted to marketable products, both facilitating biomass breakdown and the conversion of its components.
More information onBiorefinery on the National Renewable Energy Laboratory (NREL - US Government)
Biorefinery on wikipedia
Biobased Industries Initiative