Nov-2020

Beyond the renewable energy directive (RED) II: introduction to future of sustainable biochemicals (ERTC)

The global climate change and the needed GHG emission reduction, as well as increasing awareness of the circular economy have pushed towards thinking about a bio-based sustainable economy.

Varun Ginotra and Larissa Perotta
Axens

Article Summary

Many efforts have already started towards decarbonising the transport sector through the use of advanced biofuels, and several countries and regions have supported it through mandates (RED II, RFS, LCFS, RenovaBio, to name a few). However, the key to a thriving bio-based economy will be developing efficient and cost-effective processes, and integrating them in the existing infrastructure.

The bio-based economy is based on developing several bio-based building blocks (chemicals and polymers) and materials. This multiproduct solution can also answer the pertinent economic challenges of biomass-related projects. Task 42 of IEA Bioenergy1 was focused on biorefining in a circular economy, including the co- production of fuels, chemicals (combined heat and power), and biomass materials. Under this task, a classification method for the biorefining system was developed.

Futurol technology as the backbone of advanced sugars
Futurol™ technology has been developed to address the challenge of production of ethanol from lignocellulosic biomass (agricultural and forest residues, energetic crops). It was developed by a consortium of R&D partners (IFP Energies nouvelles, INRA, Lesaffre, and ARD) whose expertise covers the whole production chain, from biomass cultivation and transformation — through biocatalyst development and selection — to the development and industrialisation of fuels and petrochemical production processes, two wide applications of this advanced, second-generation product.

Lignocellulosic biomass is mainly composed of carbohydrate polymers (cellulose and hemicellulose) and aromatic polymers (lignin). These carbohydrate polymers are formed of different sugar monomers:
- Cellulose: mainly C6 sugar monomers
- Hemicellulose: mainly C5 sugar monomers

Futurol technology is a simple and integrated four-step process aiming at: deconstructing the biomass through thermomechanical and enzymatic processes in order to release all potential C5 and C6 sugars it contains and then transforming those sugars into ethanol through a fermentation step and purifying the final products (Figure 1). Another important feature is the integrated on-site biocatalysts production section which ensures process performance, reliability, and economics are present.

C5 and C6 sugars as a platform for bio-based chemicals
Futurol also opens the door to a wider exploration of the bio-based economy: it unlocks the access to advanced sugars, a suitable feedstock for many different chemical and biochemical (fermentation) processes sourcing bio-based chemicals. By combining biomass deconstruction steps from Futurol, on-site enzymes production, and a few additional separation and purification operations, it is possible to obtain C5 and C6 sugar-rich streams, separately or not.

Accessing sugar platforms will be one of the critical pathways for producing chemicals from biomass. There are several opportunities to make intermediates for drop-in molecules as well as new sustainable chemicals and plastics, some of which are exemplified in Figure 2.

Sugar platform has been developed integrating pretreatment and on-site enzyme production blocks from Futurol technology (Figure 3). The production of advanced C5/C6 sugars is based on enzymatic hydrolysis followed by separation and concentration of C5 and/or C6 sugars or a mix of C5/C6 sugars, as required by the final application.
 
› Pretreatment The primary pretreatment objective is to deconstruct the lignocellulosic biomass and prepare three major components: cellulose, hemicellulose, and lignin (Figure 3).

Pretreatment combines physical and/or chemical treatments in order to increase cellulose and hemicellulose accessibility and favour their conversion in the downstream sections. Some of the polysaccharides are depolymerised to release their embedded monomeric sugars.

›    Biocatalysts production Cellulose hydrolysis is performed using enzymes, which depolymerise the carbohydrates polymers into simple sugars (Figure 3).
On-site enzyme production has economic advantages to the purchase of these biocatalysts on the open market, as it efficiently and reliably produces biocatalysts using lignocellulosic substrate, and eliminates transportation costs and third-party margins from the producer’s balance sheet.

› Hydrolysis Cellulose hydrolysis is performed on C5-rich biomass or not, according to final product mix specification (Figure 3). Very high hydrolysis yields are achieved even in the presence of inhibitors and free sugars, thanks to tailored enzymes and operating conditions, presenting optimal activity.

› Solid/liquid separation and sugar concentration/purification According to the specifications of the chemical or biochemical process converting those sugars, C5 and C6 sugars may be separated, purified, and concentrated.

Reference
1 Bio-Based Chemicals — a 2020 Update (IEA Bioenergy).
Varun Ginotra, Business Development Manager, Renewables Business Group
Larissa Perotta, Technology Team Manager, Renewables Business Group

This short article originally appeared in the 2020 ERTC Newspaper, produced by PTQ / DigitalRefining.

You can view the digital issue here - https://online.flippingbook.com/view/1029582