Biomass pre-treatment

Focusing on wheat straw, miscanthus and organic fibre from Municipal Solid Waste, ButaNext will develop innovative techniques to optimise the biobutanol production process. The pre-treatment of the feedstock will be improved through two types of innovations:

 

Mechanical and thermochemical improvements

ButaNexT will design and construct a biomass milling process to reduce feedstock particle size, ensuring a higher yield at subsequent stages while also being more energy efficient.

 

Enzymatic hydrolysis

ButaNexT will develop more specialised enzyme cocktails to be used during biomass hydrolysis, leading to a reduction in the quantity of enzymes required, as well as time and cost savings.

 

(Picture: Pre-treatment reactor, CENER)

Fermentation

The project aims to redesign the fermentation process to produce butanol as the sole product in high yield. This will be achieved by producing and using next generation, non-GMO, homo-fermentative microorganisms that have an increased tolerance to butanol and feedstock-derived inhibitors, and by coupling the fermentation process with In-Situ Product Recovery (ISPR).

 

The new fermention process will overcome the need for energy intensive distillation involved when separating the bioproducts from water and lead to lower costs. This will make possible to replace the current (inefficient) batch processes for biobutanol production with sustainable feedstocks based on agricultural and domestic residues (cellulosic sugars).

 

(Picture: Hydrolysis and fermentation reactors, CENER)

Downstream processing

The project will improve the separation and recovery of butanol using pervaporation. This method is more energy efficient and reduces end product inhibition, thus improving the overal solvent titres and productivity. This novel separation method also allows the use of more concentrated sugar streams reducing feedstock dilution and water requirements. 

 

This approach results in lower energy costs in the downstream processing compared to the conventional distillation section for product purification. 

 

(Picture: Lab-scale pervaporation unit, VITO)

Blending performance and emissions

The project will demonstrate the superior properties of butanol as fuel extender by optimising blends with gasoline and diesel as well as with conventional biofuels (bioethanol & biodiesel) to improve their performance characteristics. Butanol can indeed be blended with diesel or
biodiesel up to 40%, and with gasoline up to 16%. The most promising blends will be selected and validated for use as next generation biofuels for both gasoline and diesel engines.

 

This will be done with two objectives: propose optimal replacements of ethanol by butanol in commercially available E-85 blends and evaluate a possible replacement of gasoline by butanol in those blends.​ Vehicle tests will be carried out. These test will include the simulation of cold conditions where alcohols could cause cold start problems.

 

(Picture: Vehicle testing infrastructure, UCLM)