13 Biorefinery Types and their Characteristics Explained

Biorefinery types are; phase I, phase II, phase III, physical, chemical, biochemical, thermochemical, first-generation, second-generation, third-generation, agricultural, industrial, municipal. They are distinguished based on product multiplicity, processing method, feedstock composition and feedstock source.

This article discusses the biorefinery types and their characteristics.


-Types of Biorefineries based on Product Multiplicity

-Types of Biorefineries based on Processing Method

-Types of Biorefineries based on Feedstock Composition

-Types of Biorefineries based on Feedstock Sources




-Types of Biorefineries based on Product Multiplicity

The types of biorefineries based on product multiplicity (the number of products formed) are; Phase I, Phase II, and Phase III biorefineries [7];


1). Phase I Biorefinery (as one of the Biorefinery Types)

Phase I biorefinery is a type of biorefinery which can convert one type of biomass feedstock using a single mechanism or process, to form a single major product.

It can otherwise be referred to as ‘single feedstock-single process-single product’ biorefinery.

Compared to other types, phase I biorefineries are less-complex. They are equipped with reactors and extraction systems that are designed and optimized for a few, definite functions.

What this means is that the working conditions and expected products of a phase I biorefinery are well-known or predetermined. As a result, it is more possible to achieve high levels of energy conservation, energy efficiency and performance, using this biorefinery.

The sustainability of phase I biorefineries is also higher than that of many other biorefinery types. Because of the simplicity of their operation, these biorefineries are reliable as tools for waste management, waste-to-energy conversion and biofuel production.

Phase I biorefineries may find application in industries where one type of organic waste is produced; such as agricultural, wood processing, paper and biodegradable plastic manufacturing industries.

An example of a phase I biorefinery is a chemical-conversion biorefinery which treats agricultural waste by anaerobic digestion, to produce biogas.


2). Phase II Biorefinery

Phase II biorefineries are biorefineries which use one type of feedstock, multiple biomass conversion methods, and forms multiple major products.

This type of biorefinery can be otherwise referred to as; ‘single feedstock-multiple process-multiple product’ biorefinery.

The phase II biorefinery is similar to phase I biorefinery in terms of simplicity. This is because it uses a single type of biomass feedstock. In general, the complexity of biorefineries increase with the complexity and multiplicity of feedstock.

However, compared to phase I type, phase II bioreactors are equipped to form, isolate and extract more than one major conversion product.

In many phase II biorefineries, production of multiple major products is achieved by integrating various technologies that perform different functions simultaneously as biomass is converted. This approach makes it possible to effectively produce and isolate useful products. Phase II biorefineries are therefore integrated biorefineries.

The mode of operation of phase II biorefineries is fairly common. An example is the conversion of starchy biomass to produce biogas, bioethanol and carbohydrate derivatives [13].


3). Phase III Biorefinery (as one of the Biorefinery Types)

In terms of product multiplicity, phase III biorefinery is the most complex type.

This type of biorefinery can be referred to as ‘multiple feedstock-multiple process-multiple product’ type. It is an integrated system that is designed to convert more than one type of biomass feedstock using any of various processes, into more than one major product.

Although it has a high degree of complexity, the phase III biorefinery is a useful development that has huge prospects in the future, especially with respect to mitigating environmental degradation through organic waste management, producing renewable energy from biomass, and mitigating greenhouse gas emission through landfill waste diversion and prevention of open biodegradation.

As an integrated system, phase III biorefineries are most important where it is necessary to produce biofuel, biochemicals, and other industrial and agricultural bio-based materials [9].

The feedstock flexibility of this type of biorefinery can be both an advantage and a limitation. Its advantage arises from the versatile mode of conversion and production of these systems. At the same time, complexity, cost and technical demands are all potential limitations. Many of these limitations are being resolved with technological advancements and process optimization.

As a result of their versatility, phase III biorefineries may find application in various sectors, including textile, energy, wood, biochemical, and food processing industries.

Phase III biorefineries can be distinguished into four subcategories based on the manner of biomass conversion. These subcategories are; whole-crop, green, two-platform, and lignocellulosic biorefineries [2].

Whole-crop biorefineries are phase III biorefineries that are capable of effectively converting various types of plant biomass like sugar beet, grains and cassava, that has been specifically grown to be used as feedstock.

Green biorefineries are able to convert naturally-grown plant and animal biomass that may or may not have been cultivated specifically as feedstock.

Two-platform biorefineries are capable of processing various types of feedstocks, however, these materials are processed using segregated components or ‘platforms’.

Lignocellulosic biorefineries are designed to convert multiple forms of lignocellulosic biomass., using any of multiple processes, to yield multiple products.

Biorefinery Types: Phase III/Integrated Biorefinery (Credit: Senator Stabenow 2012 .CC BY 2.0.)
Biorefinery Types: Phase III/Integrated Biorefinery (Credit: Senator Stabenow 2012 .CC BY 2.0.)


-Types of Biorefineries based on Processing Method

The types of biorefineries based on method of processing or biomass conversion are; physical, chemical, thermochemical and biochemical biorefineries [1].


4). Physical or Mechanical Biorefinery

Physical biorefineries are biomass-processing plants that are designed to convert feedstock using mainly physical or mechanical methods.

Such biorefineries specialize in biomass conversion methods like pressing, distillation, milling, pretreatment and separation.


5). Chemical Biorefinery (as one of the Biorefinery Types)

Chemical biorefineries are equipped to convert biomass feedstock using chemical mechanisms, reactions and methods like hydrolysis, oxidation, and hydrogenation.


6). Thermochemical Biorefinery

Thermochemical biorefineries are chemical biorefineries that also utilize catalysis, high temperature and high pressure to facilitate the chemical reactions involved in conversion of biomass.

The methods that are prominently by these biorefineries include pyrolysis, gasification, and torrefaction.


7). Biochemical Biorefinery (as one of the Biorefinery Types)

Biochemical biorefineries are biomass-processing facilities that use biologically driven chemical process, materials and methods, to convert feedstock into desired end-products.

This type of biorefinery uses technologies and techniques that are also associated with bioremediation and organic environmental management. These include anaerobic digestion, and fermentation.


-Types of Biorefineries based on Feedstock Composition

Biorefinery types based on feedstock composition are; first-generation, second-generation, and third-generation biorefineries.


8). First-Generation Biorefinery (as one of the Biorefinery Types)

A first-generation biorefinery is a type of biorefinery that converts sugar, starch and oil-based feedstock into bio-based chemicals and fuels [5].

This type of biorefinery is also referred to as ‘Sugar and Starch Biorefinery’ (SSB), and ‘Triglyceride Biorefinery’ (TGB). Biomass feedstock that are starchy, sugary, and oil-based are called ‘first-generation feedstock’. Examples include corn, sugar beet, sugar cane, animal fat and vegetable oil.

First-generation biorefineries usually operate by chemical and biochemical conversion methods, such as anaerobic digestion, transesterification and hydrolysis. Bio-ethanol and organic acids are common products in these biorefineries.


9). Second-Generation Biorefinery

Second-generation biorefineries are designed to effectively convert plant biomass that contains lignocellulose [4]. It is also called ‘Lignocellulosic Biorefinery’ (LCB).

This type of biorefinery is very important because lignocellulosic plant material is a relatively abundant form of organic matter [10]. Lignocellulosic biorefineries are looked upon as a technology by which fossil fuels could potentially be replaced by renewable biomass as an energy source.

Examples of lignocellulosic feedstock (LFC) are straw, grasses and wood. The chemical composition of these materials may vary depending on the nature and source. However; lignin, hemicellulose and cellulose are three of the major chemical components.

Based on the major products formed, lignocellulosic biorefineries can be categorized into biomethane-based, biohydrogen-based, and bioethanol-based subtypes.

Biorefinery Types: Lignocellulosic Plants as Feedstock for Second-Generation Biorefineries (Credit: Hamsterdancer 2011 .CC BY-SA 3.0.)
Biorefinery Types: Lignocellulosic Plants as Feedstock for Second-Generation Biorefineries (Credit: Hamsterdancer 2011 .CC BY-SA 3.0.)


10). Third-Generation Biorefinery (as one of the Biorefinery Types)

Third-generation biorefineries specialize in the conversion of microalgae as a substrate or feedstock [12].

The aim of developing this type of biorefinery is to be able to produce useful biochemicals and biofuel from aquatic biomass. Although microalgae are the main third-generation feedstock, macroalgae can also be used.

In order to have a sustainable supply of feedstock, microalgae can be cultivated on a large-scale and used in third-generation biorefineries [8].

The products of converting third-generation biomass include bioethanol, biodiesel, and a wide range of biochemicals.


-Types of Biorefineries based on Feedstock Sources

The types of biorefineries based on feedstock source are; agricultural, industrial and municipal biorefineries.


11). Agricultural Biorefinery (as one of the Biorefinery Types)

Agricultural biorefineries are facilities used to convert agricultural biomass into bioenergy and useful chemicals.

This type of biorefinery highlights and exploits the link between agriculture and energy, and is considered to be a sustainable and environment-friendly option [3].

Agricultural feedstock may occur in the form of plant and animal waste from agricultural activities, residue, and specially cultivated crops.

Biomass from forests, which could be residue from deforestation or forest management activities, is often classified as agricultural feedstock.

Products from agricultural biorefineries, like digestate and biochar, can be used in sustainable farming as organic fertilizer for soil conservation [11].


12). Industrial Biorefinery

Industrial biorefineries are biorefineries that use feedstock derived from industrial processes as residue or waste.

Examples of such feedstock include wood chippings, paper, and residue from bioplastic manufacturing. These biorefineries may not depend solely on industrial organic matter as feedstock, but could also make use of other types and sources of organic matter.


13). Municipal or Domestic Biorefinery (as one of the Biorefinery Types)

As the name implies, municipal biorefinery derives its feedstock in the form of municipal organic waste.

This type of biorefinery is very common, and operates in areas where such materials can be easily accessed. Examples of suitable feedstock for municipal biorefineries include food waste, paper, yard waste, paper, and cardboard.

These materials can be sorted from municipal solid waste or diverted from landfills. The operation of municipal biorefineries can be a sustainable and cost-effective way to treat waste.



Types of biorefineries are;

  1. Phase I Biorefinery
  2. Phase II Biorefinery
  3. Phase III Biorefinery
  4. Physical or Mechanical Biorefinery
  5. Chemical Biorefinery
  6. Thermochemical Biorefinery
  7. Biochemical Biorefinery
  8. First-Generation Biorefinery
  9. Second-Generation Biorefinery
  10. Third-Generation Biorefinery
  11. Agricultural Biorefinery
  12. Industrial Biorefinery
  13. Municipal or Domestic Biorefinery


They are classified based on product multiplicity, processing method, feedstock composition, and feedstock source.



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