A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power, heat, and value-added chemicals from biomass. The biorefinery concept is analogous to today’s petroleum refinery, which produce multiple fuels and products from petroleum.

The biorefinery principle is similar to that of an oil refinery, where the complex compound crude oil is separated into individual fractions or components. Some of these are converted by chemical processes into other, better settleable compounds.

Biorefineries are intended, among other things, to supplement and replace crude oil as an important raw material in the chemical industry. In addition, the variety of different chemical compounds in biomass could also create new applications. Other important factors are climate and environmental protection efforts.

The concept of biorefinery with a holistic and high-quality use of biomass is currently still in development. In approaches, this concept is already implemented, eg. As in the production of sugar, bioethanol and biodiesel, where it is trying to use the by- products or by- products of high quality. Also biogas plants are sometimes called biorefinery.

The International Energy Agency Bioenergy Task 42 on Biorefineries has defined biorefining as the sustainable processing of biomass into a spectrum of bio-based products (food, feed, chemicals, materials) and bioenergy (biofuels, power and/or heat).

By producing multiple products, a biorefinery takes advantage of the various components in biomass and their intermediates therefore maximizing the value derived from the biomass feedstock. Some researcher have considered the exploration of a biorefinery as a practical method of improving the economic performance of stand-alone biomass to bioenergy system since biochemicals are produced A biorefinery could, for example, produce one or several low-volume, but high-value, chemical or nutraceutical products and a low-value, but high-volume liquid transportation fuel such as biodiesel or bioethanol. At the same time generating electricity and process heat, through combined heat and power (CHP) technology, for its own use and perhaps enough for sale of electricity to the local utility. The high-value products increase profitability, the high-volume fuel helps meet energy needs, and the power production helps to lower energy costs and reduce greenhouse gas emissions from traditional power plant facilities. Although some facilities exist that can be called bio-refineries, the bio-refinery has yet to be fully realized. Future biorefineries may play a major role in producing chemicals and materials that are traditionally produced from petroleum.

Raw material biomass
The concept of a biorefinery depends essentially on the available raw material. Above all, concepts that include wood, starch plants and other fresh or ensiled plants as a raw material basis are discussed.

Biomass is very complex composed of many different organic compounds in very different proportions. A large proportion of the compounds are compounds that belong to the fats, carbohydrates or proteins (proteins). In addition, there are numerous other compounds, but usually occur in lower proportions, such as. B. the secondary metabolites (or secondary plant substances).

Depending on the biomass, these proportions vary. Wood, for example, has a distinctly different composition compared to starch plants (eg wheat, maize), oil plants (oilseed rape, grass, soybeans) or plant waste.

Plant Concepts
In a biorefinery, attempts are made to isolate certain high-quality compounds from the biomass. In doing so, nature’s synthesis advantage is used to either replace expensive, artificial manufacturing processes or to gain complex, non-artificially synthesized compounds.

You can for pharmaceutical purposes and as basic chemicals. Since they usually make up only a small proportion, a large part of the biomass remains behind. This can in turn z. As food, feed, or less high-quality chemicals are obtained. Once these recyclable fractions have been extracted from the biomass, the remaining fraction can still be used for energy purposes. It can as power and heat for plant operation or for sale, or biofuels or synthetic fuels (BtL, methanol, biomethane, etc.) are generated.

In addition to the extraction of compounds present in the biomass, the production of new compounds from the raw material is another field of activity within a biorefinery. Here, chemical processes, such as the already mentioned production of synthetic fuels can be used, but in particular also biotechnological approaches for the production of higher-value compounds.

The three common, discussed plant concepts are named after the respective raw material:

Typology
Several types of biorefineries are sometimes distinguished:

depending on the raw material or its source (eg marine, vegetable, animal, fungal or forestry, agricultural, organic waste, etc.),
depending on the processes used: biorefineries green (enhancing compounds typically unstable high humidity), cereals, oilseeds, microalgae or macro algae, lignocellulosic materials or whole plants.
according to the end products resulting from the transformation, in particular by bringing together under the same category all the biorefineries producing a type of product (synthesis gas for example).

Lignocellulosic biorefinery
A lignocellulosic biorefinery uses the raw material wood, which consists to a large extent of lignocellulose – a structure of lignin and cellulose – and hemicellulose. Also similar composite biomass, such as straw and grass, and waste from the paper industry, such. As the incurred in large quantities lignin-rich black liquor can be used.

Lignin consists mainly of derivatives of the aromatic compound phenol, which could be useful for the chemical industry. Cellulose is a polysaccharide (polyhydric sugar) from the monomer glucose (a hexose). This can lead to various basic chemicals, such. As ethanol and ethene as starting material for the production of polyethylene (PE) and polyvinyl chloride (PVC) or to hydroxymethylfurfural as a starting material for the production of nylon, further processed. In addition, glucose is a substratefor biotechnological production processes by fermentation. Hemicellulose is also a polysaccharide, but from different pentoses as a monomer. This can also be a particular furfural – derivative are processed or nylon and other products.

Whole plant biorefinery
A whole plant biorefinery uses the full crop, such as B. corn, wheat, rye, triticale, etc. The plants consist essentially of the grain and the lignocellulosereichen straw, which are usually already separated at harvest with a combine harvester. The straw can be further processed in a lignocellulosic biorefinery or converted into synthesis gas (syngas) by pyrolysis. This forms the basis for synthetic fuels such as biomass-to-liquid (BtL) or methanol, The grain consists mainly of the glucose polymer starch, which can be further processed in many ways. You can z. B. can be used directly as a raw material of the food or chemical industry. The production of bioplastics, such. As thermoplastic starch and use as a fermentation substrate are possible.

Green biorefinery
The Green Biorefinery uses plant material, such as As grass, clover, alfalfa or immature (green) grain from agriculture. A major difference with the other two concepts is that the fresh plant is used, the ingredients different from wood or abgereiften plants significantly. The first treatment step is the squeezing of the plant juice. The press cake mainly contains fibers (cellulose), as well as starch, dyes and pigments. In the press juice are proteins, amino acids, organic acids, etc. This could, for. B. products likeLactic acid, amino acids, ethanol etc. can be isolated. The press cake can be used as feed, for the production of syngas and biogas or for the extraction of chemical compounds.

Procedures and Products
In the biorefinery, a variety of procedures is necessary to prepare the raw material, isolate certain fractions and derive further connections with chemical, chemical-physical and biotechnological processes:

Preparation z. By:
Press
Crushing by grinding, shredding etc.

Separation and isolation by (see also separation process (process engineering):
Sieving and filtration
extraction
chromatography
Etc.

With these methods, substances and compounds already present in the biomass can be obtained. By chemical change, the product range can still be significantly expanded:

Processing with chemical and chemical-physical processes:
Pyrolysis for the production of synthesis gas
Use of synthesis gas for the synthesis of new compounds, eg. B. BtL and other hydrocarbons by Fischer-Tropsch synthesis
Combustion to generate electricity and heat

Chemical modification using biotechnological processes (see also Biotechnology and White Biotechnology):
Use of the raw material or of fractions for fermentations, eg. B. for the production of basic and fine chemicals, ethanol, biogas, raw materials for the production of bioplastics, vitamins, amino acids, etc.
Biocatalysis with isolated enzymes for the modification of certain compounds, eg. B. with amylases for the hydrolytic cleavage of starch to glucose

Examples
The fully operational Blue Marble Energy company has multiple biorefineries located in Odessa, WA and Missoula, MT.

Canada’s first Integrated Biorefinery, developed on anaerobic digestion technology by Himark BioGas is located in Hairy Hill, Alberta. The Biorefinery utilizes Source Separated Organics from the metro Edmonton region, Open Pen Feedlot Manure, and Food Processing Waste.

Several potential biorefinery examples have been proposed, starting from feedstocks such as tobacco, flax straw and the residues from the production of bioethanol. Biorefineries have also been proposed to gather as much materials from trees (i.e. cellulose, hemicellulose, lignine, lipids) as possible.

Chemrec’s technology for black liquor gasification and production of second-generation biofuels such as biomethanol or BioDME is integrated with a host pulp mill and utilizes a major sulfate or sulfite process waste product as feedstock.

In Austria, a green biorefinery was opened in May 2009 as a demonstration facility. There is grass silage used to be derived from the amino acids and lactic acid. Fixed fractions are energetically utilized in a biogas plant. It can process 4 tons of grass silage per hour or 100 liters of pressed juice per hour. From 150 to 210 kg of lactic acid and from 80 to 120 kg of crude protein (amino acids) can be obtained per tonne of silage dry matter. The aim is to gain insights that support the design of industrial plants.

In one of the agency Renewable Resources e. V. coordinated project have been developed since 2007 process concepts for lignocellulosic biorefineries. In a follow -up project, a first pilot plant will be set up in Leuna (Saxony-Anhalt), processing 1.25 t of wood per day. In the long term, plants with processing capacities of 400,000 t / a are considered possible.

The Biowert plant works with a principle similar to the Green Biorefinery. The raw material is grass or grass silage. This is pressed and the liquid fraction in a biogas plant, which also supplies process energy or process heat, fermented. The press cake contains a high proportion of fiber from which insulation materials or fibrous additives for plastic (natural fiber reinforced plastic) are produced.

Health significance
In all of the refined vegetable oils are 3-MCPD-fatty acid ester to find, wherein the contents differ widely in part. 3-MCPD was classified as a “candidate human carcinogen ” in 2011 by the International Agency for Research on Cancer (IARC).

Perspective
According to a market study by Festel in 2001, the share of biotechnologically manufactured chemicals with 30 billion US $ was about 2.5% of the total market. By 2010, an increase of approximately 20% was predicted (310 billion US $ with a total turnover of 1600 billion US $). In 2007, the share was US $ 48 billion, which was 3.5%. In 2010, the proportion of biotechnologically produced drugs was 17%.

The development of the biorefinery has been intensively promoted in the USA in recent years. Approximately $ 360 million was invested in biomass production each year (2003: approximately $ 420 million, 2005: approximately $ 310 million). There, experts expect that by 2020 a quarter of the current fossil-based organic materials and 10% of the oils and fuels will be produced using biorefinery technologies.

In the EU, a total of € 74 million has been invested in research into the use of biomass under the Sixth Research Framework Program from mid-2002 to 2006. In the 7th Research Framework Program (2007-2013), the total annual budget has been increased by 40%, so that an increase in biomass utilization research is also expected.

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