Dante A. Simonetti

Catalytic Conversion of Biomass to Monofunctional Hydrocarbons and Targeted Liquid-Fuel Classes

It is imperative to develop more efficient processes for conversion of biomass to liquid fuels, such that the cost of these fuels would be competitive with the cost of fuels derived from petroleum. We report a catalytic approach for the conversion of carbohydrates to specific classes of hydrocarbons for use as liquid transportation fuels, based on the integration of several flow reactors operated in a cascade mode, where the effluent from the one reactor is simply fed to the next reactor. This approach can be tuned for production of branched hydrocarbons and aromatic compounds in gasoline, or longer-chain, less highly branched hydrocarbons in diesel and jet fuels. The liquid organic effluent from the first flow reactor contains monofunctional compounds, such as alcohols, ketones, carboxylic acids, and heterocycles, that can also be used to provide reactive intermediates for fine chemicals and polymers markets.

Modeling Ethanol Decomposition on Transition Metals: A Combined Application of Scaling and Brønsted−Evans−Polanyi Relations

Applying density functional theory (DFT) calculations to the rational design of catalysts for complex reaction networks has been an ongoing challenge, primarily because of the high computational cost of these calculations. Certain correlations can be used to reduce the number and complexity of DFT calculations necessary to describe trends in activity and selectivity across metal and alloy surfaces, thus extending the reach of DFT to more complex systems. In this work, the well-known family of Brønsted-Evans-Polanyi (BEP) correlations, connecting minima with maxima in the potential energy surface of elementary steps, in tandem with a scaling relation, connecting binding energies of complex adsorbates with those of simpler ones (e.g., C, O), is used to develop a potential-energy surface for ethanol decomposition on 10 transition metal surfaces. Using a simple kinetic model, the selectivity and activity on a subset of these surfaces are calculated. Experiments on supported catalysts verify that this simple model is reasonably accurate in describing reactivity trends across metals, suggesting that the combination of BEP and scaling relations may substantially reduce the cost of DFT calculations required for identifying reactivity descriptors of more complex reactions.

Catalytic Production of Liquid Fuels from Biomass‐Derived Oxygenated Hydrocarbons: Catalytic Coupling at Multiple Length Scales

The catalytic processing of biomass‐derived feedstocks to liquid fuels and chemical intermediates is complex and expensive. Therefore, conversion processes involving a limited number of reaction, separation, and purification steps are necessary. Coupling of catalytic processes has the potential to lead to the development of new processes, thereby improving the overall economics of biomass conversion. Functional coupling at the molecular scale has the potential to produce novel catalytic materials to replace homogeneous catalysts. Active site coupling of different sites within the same reactor can help reduce operating costs by combining sequential reactions in a single reactor. Chemical reaction coupling of heterogeneous and homogeneous reactions may lead to improvements in overall catalytic performance for liquid phase processes by enhancing surface reactions with liquid phase reactions. Finally, phase coupling leads to improvements in overall yield by improving the equilibrium conversion or by suppressing undesired side reactions.

Catalytic Strategies for Changing the Energy Content and Achieving CC Coupling in Biomass-Derived Oxygenated Hydrocarbons

This Concept examines the opportunities for the use of biomass feedstocks in the production of liquid fuels for the transportation sector of society. The cost-competitive conversion of biomass into liquid fuels involves the integration of processes that operate on lignocellulosic feeds with processes that convert specific fractions of lignocellulose. A brief description of current energy systems is given to indicate the potential contributions of biomass to replace fossil fuel feedstocks for energy production, followed by a description of current biomass-conversion technologies. Specific focus is given to promising reaction pathways and novel research opportunities for conversion of the carbohydrate fraction of lignocellulose into fuels with targeted structures.

Conversion of Glycerol to Liquid Fuels

Abstract A significant fraction of the total petroleum supply is used for transportation in the form of liquid hydrocarbons. This fact, along with the increasing demand for oil in developing countries has led to substantial research efforts in the area of renewable liquid fuels. One alternative is the conversion of vegetal oil and animal fat into bio-diesel. However, this comes with the production of significant amounts of glycerol, a byproduct that will become abundant if large scale bio-diesel production is implemented. In order to increase the total biomass to fuel efficiency during the production of bio-diesel and address the overproduction of glycerol, a novel integrated Glycerol Reforming (GR) + Fischer-Tropsch (FT) process is presented. The novelty of this process lies in the use of a Rhenium-based catalyst for the conversion of aqueous glycerol to synthesis gas (syngas). This step reduces significantly the cost of syngas production in traditional green FT processes. This work presents a preliminary process synthesis and an economic evaluation for a medium capacity GR-FT plant. The results show that the integrated process is economically attractive, and that there is room for further improvements trough the use of systematic process design and optimization methodologies.