Biorefinery technology

– to break oil dependency and climate-secure our society, technologies are required that enable the use of renewable raw materials in the manufacture of climate-neutral chemical products

We provide the technology for a climate-safe society

We have developed processes and technologies that make it possible to manufacture bio-based products and advanced biofuels. Biorefinery technology that we offer companies with some form of cellulose-based biomass that they want to utilise and refine. Our technology makes it possible to produce new sustainable raw materials such as cellulose sugar, lignin and ethanol for the production of sustainable products. This is our contribution to a better environment.

This technology consists primarily of four steps: pretreatment, enzymatic hydrolysis, fermentation and distillation:

Pretreatment

In the first step, the raw material is pretreated with dilute acid (sulfuric acid or sulfur dioxide) and steam up to about 170 – 200 degrees depending on the raw material, which converts hemicellulose into sugar.

Hemicellulose is more easily accessible and reactive than the long cellulose molecules and comprises various monosaccharides, mainly mannose, glucose, xylose and arabinose. The pretreatment releases sugar from the hemicellulose and makes the cellulose assessible for enzymatic hydrolysis.

Enzymatic hydrolysis

In the second step, enzymes that hydrolyse the cellulose are added to sugars. After this process, since cellulose is mainly composed of chains of linked glucose molecules, what remains is glucose i.e. ordinary sugar. This can be fermented to ethanol.

SSF and SHF are variants of the enzymatic hydrolysis process.

Hydrolysis and Fermentation (SSF)

SSF is an abbreviation for Simultaneous Saccharification and Fermentation, i.e. simultaneous saccharification with enzymes and fermentation in the same vessel.

In order to be able to avoid separating the sugar solution from the solid before fermentation, hydrolysis and fermentation can be carried out simultaneously. It provides higher alcohol content, but at the same time places higher demands on the yeast used in the process since the environment is inhospitable.

Separate Hydrolysis and Fermentation SHF

SHF is an abbreviation for Separate Hydrolysis and Fermentation. This method means that the saccharification with enzymes and the fermentation of the released sugar take place in two separate steps.

For those customers who want to produce other chemicals from the sugar, SHF can be an advantage as one acquires a sugar stream, which can then be further processed, for example concentrated, purified or through some other process step.

SEKAB E-Technology masters both variants and their different variations. Both techniques have their advantages and disadvantages depending on what the sugar is to be used for, what raw materials are to be used and how the co-products (lignin and biogas) are to be used. The choice therefore becomes specific to each facility.

Fermentation

Fermentation is a biological process in which microorganisms incompletely oxidise organic compounds. In this case, a variety of sugars are converted to ethanol or other chemicals from yeast fungi.

Plain yeast (baker’s yeast) is better at converting six-carbon sugar, hexoses, than other sugars. Hemicellulose from agriculture and deciduous trees also contains several different five-carbon sugars, pentoses. Consequently, it is desirable that the yeast used can also convert them to ethanol.

Sekab E-technology has partnered with Taurus Energy and other yeast manufacturers to verify that their special yeast strains also function on an industrial scale. These yeast strains are capable of fermenting both hexoses, six-carbon sugars and pentoses, five-carbon sugars.

Distillation

The ethanol is distilled

After fermentation, the mixture is distilled and the ethanol can be purified and dewatered, sold or further refined.

Filtration/Lignin separation

Raw materials containing cellulose consist largely of lignin, a substance that cannot be desugared in the process. It is separated by filtration either before or after fermentation and distillation. The lignin is then washed and dewatered to a water content of around 50 per cent.

Lignin has high-energy content and can be used directly as a solid biofuel to provide the plant with energy. It can also be further refined into various products, such as polymers and adhesives, and this is an area in which research is ongoing all over the world.

Biogas

After distillation and filtration, some dissolved substances remain in the process water, which can be digested into biogas using various microorganisms. The biogas can either be used to provide energy in the process, or it can be further refined into liquefied natural gas. Sekab collaborates with researchers and commercial supplier companies in this area to optimise the production of biogas from the cellulose process.

Read more about the application of our technology

Hi!

Do you have questions or concerns?