NIBCON
Novel integrated biorefinery concepts for a carbon neutral bio-economy
Context
The transition from fossil-based European industries to carbon neutral and sustainable ones is a major challenge. It entails the transformation of conventional industrial processes and products into environmentally friendly biobased versions. There is a need to develop more sustainable variants of classic fossil-type chemical building blocks, materials and processes, particularly when the whole life cycle is considered. The utilization of abundant renewable 2nd generation biomass and sidestreams, coupled with less energy intensive processes can contribute in part to a reduction in greenhouse gas emissions or the replacement of toxic elements and should therefore be considered as crucial parameters in the development of sustainable products manufacturing for a future circular and biobased economy. This highly interdisciplinary SBO trajectory aims at the introduction of the synthesis and application of unique biobased products in future Flemish and European chemical and engineering industries. It is built around inventive biorefinery processes consisting of well-chosen, integrated technologies for sustainable feedstock conversion and their downstream separation. While developing the technologies to synthesize biobased primary building blocks, the environmental and economic sustainability is being evaluated using life cycle and techno-economic assessments. As such it is guaranteed that the developments not only result in technically feasible, but also sustainable technologies.
Goals
Overall goal: Identifying and converting sustainable and suitable 2nd generation biomass feedstock via biorefining technologies (i.e. integrated conversion and downstream processing) based on catalytic fractionation/depolymerisation into primary aromatic building blocks supporting the transition of the petrobased industry towards a carbon-neutral chemical sector.
1. To identify most suitable and sustainable feedstocks for biorefining – ‘align to refine’
In this first Program 2nd generation crops (e.g. short rotation woods) and different sidestreams from a variety of biobased value chains are evaluated, i.e. residues from agricultural and forestry practice, bioresidues from food production and residues (lignin) from current biorefineries. This evaluation allows to gain insights into the most promising, locally available feedstocks for producing functional and unique molecules. For the evaluation, the biomass and sidestreams will be mapped, taking into account the following key criteria: (1) year-round or complementary seasonal availability, (2) environmental cost/gain (in terms of CO2 reduction), (3) price and (4) feedstock composition, quality and reproducibility . The latter criterion, i.e. feedstock quality, is important to assess the intrinsic ability of producing unique, functionalized aromatic building blocks, sugars (C5 and C6) and fibers. Advanced analytics are required to obtain detailed insights into the feedstock quality and will be described in the third paragraph as research topic of this SBO.
2. To design novel process technology – ‘design to refine’
Integrated conversion processes, based on rational and inventive catalysis, should efficiently convert these complex streams into well-defined intermediates such as natural fibers, sugars, lipids, lignin or proteins and/or platform molecules such as alcohols, acids or aromatics. The intermediate products and mixtures can be used as such or be further refined in SBO 2.
Metal-catalyzed conversion of both biomass directly and isolated lignin feedstocks, preferably ether rich lignin streams issued from biorefinery processes, is envisaged. With respect to the direct conversion of biomass, i.e. ‘lignin-first’ approach, novel reactor concepts will be simulated and validated to target continuous biorefining at pilot level. A comprehensive understanding of the chemical conversion will be achieved via fundamental models. In a true industry 4.0 manner, these models will guarantee the necessary flexibility with respect to feedstock composition and operating conditions. The Single-Event MicroKinetic methodology presents itself as an ideally suited kinetic simulation strategy for biobased feed conversion. Also metal catalysed reactions need to be dealt with, requiring an adequate representation of the catalyst.
The developed kinetics models will be embedded in reactor models accounting for the actual hydrodynamics (gas-liquid-solid reactions) and the potentially limiting transfer of reactants and products between the phases present. This is crucial, among others, to avoid hydrogen depletion at the active sites and, hence, avoid extensive coke formation. Also the thermodynamics of the reacting components will be mapped adequately. Indeed, while hydrocarbons exhibit a close to ideal thermodynamic behaviour, oxygenates include functions with more pronounced polarities that exert significant effects on the kinetics as well as the separation behaviour. Combining all the above will create a forefront tool for process simulation and design in the area of bio-based feed conversion.. These models will serve as a useful tool for the process design, including separation steps in addition to the chemical conversion.
Starting from lignin as feedstock, the solubility of lignin is key to perform the metal-catalyzed depolymerization. Hence, the solubility of different lignin streams will be investigated both at ambient conditions and increased temperature/pressure. Corresponding mass balances will be made before and after depolymerization. Based on experimental data, a model predicting lignin solubility will be targeted. In this way, the necessary input will be generated for the pilot scale production of biobased aromatics out of lignin as aimed at in the LignoValue Pilot plant (EFRO project). In both approaches, catalyst stability and recyclability is key (both from a technical, economic and environmental perspective) and will therefore be investigated at lab scale. Furthermore, new catalysts will be designed that meet these criteria. Next to the catalyst, also solvent recyclability and reuse (e.g. purity) will be investigated as these are important to take into account when developing sustainable processes.
For application development starting from the chemical building blocks produced by our conversion processes, downstream separation will be required. In-situ separation methodologies will be developed that allow for a continuous removal of converted fractions from the reactor upon formation. Hereto, novel kinetic separation concepts will be introduced, implemented and validated with lignin oil, allowing for a continuous separation of small and large molecules into several fractions based on chemical nature and size of the solutes. To enhance the separation speed, enable for scale up in a later phase and avoid fouling problems potentially occurring with challenging streams, lateral long-range mixing is implemented. The development of concepts for separation during the biomass conversion should also allow the recovery of reactive intermediates as novel products. We further aim at the development of integrated models for the downstream processing of lignin oil obtained from the catalytic conversion of lignin. In recent work, separation and isolation of valuable fractions was demonstrated, but various separation methods (including distillation, extraction, membrane separation) have to applied. Given the large cost of such sequences of downstream processes, a rational and systematic approach is needed to identify the optimal separation strategy and reduce production costs. Networks of separation units will be developed; optimization will be performed at the level of the individual separation devices and the full downstream process. Together with the experimental data of extraction, membrane separation, distillation, … already available at the partners involved, a process model to select the best separation train to obtain the desired product fractions (e.g. lignin monomeric or oligomeric fraction) will be established. With this rational approach, it is aimed to make smart combinations of separation technologies to increase the competitiveness and general sustainability of biobased chemicals.
3. To reach high yields of primary products for biobased chemicals – ‘inspiration through analysis’
As mentioned, feedstock quality is an important criterion to assess the potential of biomass/lignin to produce unique, functionalized aromatics, for which advanced analytics and chemometrics are required. In addition, biomass conversion processes generate complex mixtures of derivatives, of which the chemical identity/structure is currently often lacking.
The development of new advanced characterization techniques such as comprehensive 2D liquid chromatography (LC×LC), comprehensive 2D gas chromatography (GC×GC) as well as advanced NMR tools (1H-13C HSQC NMR; 31P NMR) will improve the chemical characterization of the initial feedstock and produced bioproducts. The effect of small compositional differences, specifically small shifts in lignin composition and their impact on the product composition, can for example be identified using principal component analysis (PCA) or more advanced analysis techniques.
Besides advanced analytics, a benchmarking will be performed with more simple analytical methods (e.g. titration, UV spectroscopy, …) to easily and quickly evaluate the quality of the feedstock and the primary aromatic building blocks. This will lead to an analytical toolbox of simple analytics, which is also current practice in the petro-based chemical industry and hence of interest for companies working on e.g. application development.