Surface enhanced spectroscopy in a flow-through microfluidic chip

One of the issues in biomass conversion is the complexity of the mixtures involved. It is therefore difficult to do (direct) analysis of this mixture. Traditional methods like gas chromatography are not always suitable because of the high water content present within biomass. In this project, the aim is to develop a microfluidic chip for on-line analysis of the products formed during biomass conversion. This microfluidic chip will contain ordered nanofabricated structures for surface enhanced Raman spectroscopy (SERS), combined with additional structures for surface enhanced infrared absorption spectroscopy (SEIRAS). SEIRAS and SERS are two complementary methods, since vibrations active in SERS are inactive in SEIRAS and vice versa. Moreover, enhancement of the spectroscopic methods is essential to lower the limit of detection.

Project leader: Dr. Mathieu Odijk

In-situ studies porous materials synthesis

In Nature, complex biomacromolecular systems have evolved to control the formation of functional inorganic materials with complex morphology and structure. Currently, it remains a challenge to synthesize such complex structures in a controlled manner. In this project, researchers will investigate in detail how novel porous oxides can be synthesized with optimal pore size, preferably large pores for efficient transport and small pores for shape selectivity, to catalytically convert large biomass molecules to useful product. The idea of the project is to assemble small building units in such way that porous structures are obtained with tunable catalytic properties. By using sophisticated analytical techniques such as (cryo)electron microscopy and in-situ SAXS/WAXS we will be able to monitor the development of structure and morphology in the reaction mixture. Insight in these processes will guide us to better control the final structures.

Project leader: Prof. Emiel Hensen

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Acidic Water in Zeolite Pores: Multi-scale Modelling of Water-Active Site Interactions

Sustainably sourced biomass may have wide applicability as renewable resource for the production of transportation fuels as well as many consumer products (plastics, car supplies, clothing). What is more, traditional – zeolite based – catalysis has been successfully explored for performing such sustainable manufacturing processes. Nonetheless, new catalytic reactions introduce new difficulties. Fuel production (via high temperature cracking of the oxygen-rich biomass molecules) involves water formation, while converting biomass poly-alcohols into chemicals often requires an aqueous environment. In both cases the presence of water in the traditional zeolite-based catalysts causes a reduction of activity over time.

Here, we will combine quantum mechanical and classical simulations to study water in zeolites, with the goal to develop guidelines to design more stable zeolite catalysts for biomass conversion. The project can be divided into two branches, involving two different simulation scales. 1) We will investigate the behavior of an active site proton in the presence of water, and its reactivity towards the cavity wall. 2) We will explore the attachment of water droplets on zeolite-representative surfaces with different shapes (i.e., flat, curved and confined), and makeup (i.e., Si/Al ratio). This thorough study will predict structure and location of zeolite water, and can provide a framework for further studies on the reactivity of the biomass compounds themselves.

Project leader: Prof. Bert Weckhuysen


Surface heterogeneity and interfacial transport

The opportunities in biomass conversion that we aim to address include obtaining the true reaction kinetics, and exploring fundamental areas related to mass transport. Microfluidics allow for intrinsic kinetics studies, due to the well-defined convection and diffusion behavior. Typical biomass conversions include multi step and multi component reactions. Surface heterogeneity, both geometrically as well as chemically, influence fluid dynamics and mass transport near the catalytic surface. We need to understand these influences in great detail on the nano- and microscopic level, in order to couple them to the largest scales in the flow. To obtain information, we propose to experimentally probe the fluid dynamics (momentum transport) and concentration profiles (mass transport) on varying length scales. We aim to obtain relations between interfacial characteristics and boundary layer mass transport, as to allow for effective interface design.

Project leader: Prof. Rob Lammertink

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Polyalcohol reforming to synthesis gas as logistic fuel for mobile fuel cell applications

The current project aims at in depth understanding of coke formation mechanisms at the surface of heterogeneous catalysts under conditions of oxidative steam reforming of polyalcohols on microscopic and molecular level.

To reach these goals, theoretical modelling (DFT), ex-situ and in-situ characterization techniques will be applied, which will be assisted by extensive evaluation of the catalyst performance under practical operating conditions. The target is the development of catalyst formulations, which are long-term stable and do not show deactivation through coke deposition.

A reactor design for an integrated membrane microchannel reformer based upon plate heat-exchanger technology will be developed, which will comprise the reforming, hydrogen purification and off-gas (retentate) combustion in a single heat-integrated device. The design can serve as basis for a future product development in the field of fuel cell auxiliary power units for aviation and military applications based upon fuel cell technology.

Project leader: Prof. Gunther Kolb

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Theory of Lewis acid zeolite catalysis for biomass conversion

Terephtalic acid (PTA) is an industrially important chemical used for the production of polyethylene terephthalate (PET), the polymer widely used for the manufacture of various synthetic fibers, composite materials and food/beverages packaging. Currently, PET is produced by oxidation of oil-derived p-xylene. The development of efficient green routes to products such as PET by using biomass as feedstock is crucial to meet the sustainability goals of the chemical industry. Zeolites are important catalysts in the upgrading of biomass to green precursors for renewable PET production. Lewis acid sites in zeolites are able to isomerize and dehydrate glucose, the main sugar component in lignocellulosic biomass, into hydroxymethylfurfural and also its subsequent conversion to desired aromatics. This route is relevant for tailored production of aromatics from sugar streams but may also play a role in catalytic pyrolysis upgrading schemes. In this project the researchers will investigate by sophisticated quantum-chemical methodologies the key aspects that control optimum reactivity of Lewis acid zeolites for upgrading of biomass. Although especially Brønsted acid catalyzed conversion in zeolites has been extensively studied, reactivity concepts of Lewis acidity in the presence of a solvent are much less developed. This project will develop such concepts with the aim to rationalize the way Lewis acid zeolites catalyze conversion of sugars and furans and provide clues how to design optimal catalysts for such conversion steps.

Project leader: Prof. Emiel Hensen

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Bio-oil to chemicals and fuels: (in situ) catalyst deactivation studies at multiple length scales

Sustainably sourced biomass is not only an excellent feedstock for renewable fuels production, but also for chemicals. Indeed, the increased use of natural gas (shale gas in particular) will lead to shortages in the key chemicals propylene, butadiene, and BTX, providing an additional economic incentive for chemicals production from biomass. Lignocellulosic bio-oils produced by catalytic pyrolysis are, after the necessary upgrading steps, are particularly attractive for both renewable fuels (addressing the energy-challenge) and chemicals (addressing projected chemicals scarcity). One of the most advantageous ways of bio-oils to fuels conversion is by co-feeding the bio-oil in a conventional fluid catalytic cracking process (FCC), but at present this approach suffers from reduced gasoline production and increased coking. Alternatively, the bio-oil can be catalytically upgraded to aromatics and olefins, a process that at present also suffers from catalyst deactivation and limited selectivity. We will study catalyst deactivation for these two processes in detail a combined experimental and spectroscopic approach to come to structure-activity relations and ultimately to guidelines for improved catalyst composition and performance. In a parallel study, a detailed FCC reactor model will be developed that predicts the performance based on first principles, which can be used to test different scenarios for the operation of these reactors.

Project leader: Prof. Bert Weckhuysen

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Catalytic Biomass Conversion by Porous Oxides

Upgrading biomass to useful chemicals and fuels remains an unsolved technological challenge. If it could be done with reasonable product yield, biomass could contribute substantially to sustainability goals allowing to reduce CO2 emissions. The most pressing problem derives from the complex heterogeneous nature of biomass. In this project, the researchers intend to develop catalysts that can convert biomass in one step into a mixture of useful compounds. The envisioned process resembles the upgrading of heavy oil feedstock for which shape-selective catalysts are used. To convert biomass, combinations of tailored catalysts are required with optimized Brønsted and Lewis acidity to improve the yield of desirable products. A new approach will be followed in which low-value olefinic by-product will be recycled to the feed with the aim to optimize the aromatics yield. Aromatics are useful fuel components but also important intermediate chemicals for the production of a wide range of products.

Project leader: Prof. Emiel Hensen

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Integrated and Structured Fluid Catalytic Cracking reactor: Gas-(Liquid)-Solid Multi-scale Modelling of a Riser Reactor with Draft Tube for Intensified and Uniform Phase Contacting

Currently, Fluid Catalytic Cracking (FCC) is used to convert crude oil into gasoline and base chemicals, such as propylene, which we can use for making plastics. There is a need to shift from fossil to more renewable resources and therefore it would be advantageous if we could develop proper FCC technology to turn biomass into a biobased feedstock for the production of fuels and chemicals. The performance of these FCC processes in terms of making the right products is not yet very well understood. It is known that the heterogeneous nature of the reactor mixture (gas-liquid-solid) has a large impact on the overall performance. We will develop a detailed reactor model that predicts the performance based on first principles, which can be used to test different scenarios for the operation of these reactors. For this purpose, a labscale FCC unit will be made in a mirror project to verify the theoretical predictions regarding heat/mass flow and overall cracking performance.

Project leader: Dr. Niels Deen

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