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BioGasol’s Value Proposition

Technology and Process Concept

Technology & Process Concept

BioGasol has focused on two areas that have been deemed necessary to evolve in order to succeed with a cost effective ligno-cellulosic biochemical conversion process. These two areas are:

 

1) The pretreatment, which opens up the biomass structure, hydrolyses the polysaccharides into fermentable monomeric sugars and allows accessibility for enzymes to hydrolyse the remaining polysaccharides. BioGasol has developed a continuous high-yielding pretreatment system which utilizes a well-known dilute acid / steam explosion process, in order to unlock more than 90% of both C6 and C5 sugars, providing an excellent starting point for any biochemical conversion process. 

 

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2) The C5 fermentation process, which utilizes the otherwise not convertible C5 sugars that comprise a major portion of the ligno-cellulosic biomass. Using a thermophilic microorganism in a continuous mode of operation, BioGasol can convert all C5 sugars (as well as remaining C6 sugars) into ethanol.

 

 

BioGasol can provide competitive solutions in both areas where solutions are required in order to enable the future biomass based industry. In order to determine the effectiveness both technically and economically, BioGasol has developed a coherent process concept, based on the two enabling technologies as well as utilising other more well-known unit operations.  

 

  

The standard BioGasol Concept "MaxiSplit" consists of the following main process steps:

1. Pretreatment - Carbofrac®

2. Separation

3. Enzymatic Hydrolysis / C6 Fermentation

4. C5 Fermentation - PentofermTM

5. Distillation

6. Anaerobic Digestion and Process Water Recirculation

 

 

Illustration of the BioGasol process Concept (MaxiSplit)



 

A great advantage of the concept is that nearly all carbohydrates in the raw material are converted into bioethanol (the main product) while the unused fraction is converted into methane. Approximately 20 percent of the input material will be separated out as a solid fuel, which can be used for combustion. Process water is recirculated to the pretreatment unit and used together with fresh raw material.

 

1. Step: Pretreatment - Carbofrac®

BioGasol has developed a highly efficient, scalable and cost effective pretreatment system for the opening of lignocellulosic biomasses, the CarbofracTM pretreatment system. It is a continuous system based on several proprietary solutions which has resulted in a feedstock flexible pretreatment platform, suitable for both acetic and alkaline processes. The standard pretreatment process BioGasol uses is a dilute acid, steam explosion process, which serves to hydrolyse the hemicellulose to monomeric C5 sugars, which can easily be separated for the dedicated C5 fermentation system.  BioGasol also has a proprietary method called wet explosion or WEX which  is a combination of steam-explosion and wet oxidation, applying both the addition of oxygen and a pressure release at high temperature.

 

2. Step: Separation - Solid / Liquid

The pretreated biomass is washed and separated into two fractions; a liquid C5 sugar (primarily xylose) fraction and a solid cellulose / lignin containing the C6 sugars (primarily glucose). 

 

 

3. Step: Enzymatic Hydrolysis and C6 Fermentation
The cellulose / lignin fraction is hydrolysed using enzymes and thereby the C6 sugars are liberated for fermentation (yeast or PentocrobeTM) into ethanol. BioGasol has experience in using various enzymes and has tested different enzymatic hydrolysis and fermentation process concepts incl. SHF (shown), SSF and SSCF.

 

4. Step: Xylose Fermentation - PentofermTM

The C5 sugar (xylose) liquid obtained after the pretreatment and separation  is fermented at an elevated temperature of approx. 70° C where the C5 sugars are transformed into bioethanol using a thermophilic anaerobic bacterium. Co-fermentation of both C5 and C6 sugars can also be achieved, since the microorganism has the inherent ability to convert all sugar types (glucose, arabinose, xylose, mannose, galactose) into ethanol.

 

 

Many biomasses and agricultural waste contain xylose in the order of 20-45 percent of the total carbohydrates and xylose is therefore the second most abundant carbohydrate monomer after glucose. Fermentation of xylose is therefore a crucial step towards reducing the overall cost of ethanol production from lignocellulosic raw materials. Historically it has been very difficult to perform this conversion, but BioGasol has worked with microorganisms that are naturally equipped to perform this specific task and has run fermentations at lab and pilot scale since the late nineties. Following a forced evolution program BioGasol has arrived at the PentocrobeTM which has show yields of more than 90% of theoretical maximum and at relatively low operating cost.

 

5. Step: Distillation

Recovery of ethanol from the fermentation effluent including dehydration into fuel-grade bioethanol. 

 

6. Step: Biogas Production and Recirculation of Process Water
After the ethanol production a part of the organics still remains in the process water. Anaerobic digestion has been used for a long time as treatment of organic waste streams. The advantages are a high reduction of organic matter in the water and the production of methane, which can be used as energy source. The great benefits, in contrast to aerobic waste treatment, are the reuse of the process water and an overall positive energy balance of the waste treatment process. The revenue from the methane produced will furthermore lower the price for the ethanol production significantly.

 

Since 2006 BioGasol has been testing the process described in the above and other variants at pilot scale at Denmark’s Technical University in Copenhagen, Denmark. In 2010 BioGasol started to operate the Advanced Pilot plant at it's then new premises at Ballerup and Køge near Copenhagen including 50kg/h (pilot) and a 1t/h (demonstration) Carbofrac® continuous pretreatment systems as well as a 250L and a 2.5m3 PentofermTM fermentation system. In 2012 BioGasol has sold the first CarbofracTM unit and began design of a 4t/h pretreatment system, which is to be deployed for the demonstration plant planned as well as for commercial applications. 

 

 

BioGasol ApS · Lautrupvang 2A · DK-2750 Ballerup
Phone: (+45) 8820 4879 · CVR: 29211655 · www.biogasol.com

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