Advanced BioFuels USA

by Mallikarjun Navalgund (Praj Industries/Biofuels Digest)  … Ethanol is a currently available solution and is being deployed to mitigate emissions from the transportation sector via the legacy energy infrastructure that has existed for over a century. The first generation(1G)/conventional ethanol industry is well established all over the world and more than 110 billion liters (~29 BGPY/88MTA) of ethanol is being produced every year. This eliminates around 70 million metric tonnes of CO₂ emissions. What if we could amplify the emissions reductions many times over by producing ethanol using a feedstock that is far more abundant and is currently of low value.

Cellulose is the most abundant molecule around us, of which quite a large part is a residue or waste. Advanced ethanol produced from this cellulosic feedstock is a low-carbon fuel. To top it off, many supporting policy initiatives have been put in place by legislators in the US and EU amongst others. With this backdrop, there is a strong rationale for the industry to ramp up the production capacity of advanced ethanol.

However, a few technology demonstration projects have not delivered the expected outcomes.   Hence, the maturity of the underlying technology to process lignocellulosic feedstock to bioethanol has been perceived as being one of the hurdles in not achieving its potential.

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The pre-treatment process step is the major differentiating step between the conventional and advanced ethanol production technologies. (To get deeper insights into the pre-treatment process, Click here.)

The perceived risk of cellulosic ethanol technology can be overcome, and the benefits of this already available solution can be reaped using Praj’s enfinity technology.

The following are reportedly the technology challenges, encountered in the first few cellulosic ethanol technology demonstration plants:

• In-efficient pretreatment system
• Hurdles in bioprocessing
• Difficulty in synchronized operations

1. Successful pre-treatment is key for improved economics

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A. Low Process efficiency:

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The pre-treatment step ‘prepares’ the feedstock for hydrolysis. This ‘preparation’ takes place in two steps:

• Deconstructing the biomass i.e., separation/ loosening of lignin from cellulose and hemicellulose. This makes the cellulose available for enzymatic hydrolysis.
• Opening of the carbohydrates makes them porous for more efficient hydrolysis. This improved efficiency not only converts more of the carbohydrates to sugars but at the same time achieves it with the lowest quantity of enzymes.

B. Compromised plant availability: One of the reasons for the plant availability being compromised is the extraneous material that invariably accompanies the biomass feedstock which is also accompanied by soil/gravel. Equipment is prone to get damaged due to the abrasive effect of sand/soil.

Handling fibrous and contaminated feedstock like cassava (1G Feedstock) has provided Praj valuable experience to tackle challenges associated with its processing.

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2. Bioprocessing backed by experience

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Cellulosic feedstock, difficult feedstock

Physical complexity

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Chemical complexity

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3. End-to-end integration 

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A. Energy and water integration:

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B. Process integration

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Validation

Three Fortune 500 energy companies have already shown their confidence by signing licenses for Praj’s enfinity technology for their commercial-scale projects. The first of the projects is scheduled for completion by the middle of 2022 with the other two projects succeeding with a gap of 6 months each.

In addition to enfinity, Praj’s offers Celluniti technology in collaboration with Sekab, Sweden. Celluniti harnesses soft-wood from forestry residues to produce cellulosic sugars, biofuels & chemicals. Both Cellutniti & enfinity technology are also useful for the production of sustainable aviation fuels (SAFs) & marine biofuels paving the way for greening these sectors too.  READ MORE