2013 Annual Report
1a.Objectives (from AD-416):
The objective of FarmBio3 is twofold: (i) to leverage the existing synergies among partners to further research and optimize pyrolysis pathways to commodity fuels and chemicals and improve the TRL 4 status already achieved at ARS and (ii) increase to on-farm scale that will enable the current state of technology to, TRL 6, commercial status.
1b.Approach (from AD-416):
Will focus on three feedstocks that are important to U.S. agriculture including switchgrass, horse manure and woody biomass. The primary conversion platform will be catalytic and non-catalytic fast pyrolysis for production of stable fuel intermediates. Because barriers to utilization of such intermediates are high we will develop more robust multi-functional heterogeneous catalysts to balance deoxygenation pathways to minimize oxygenate production while increasing carbon efficiency for the selected feedstock pool. Bifunctional catalysts will be developed to upgrade and optimize carbon distribution in the condensed phase pyrolysate to achieve C6-C14 hydrocarbons and target entry to gasoline, diesel and jet range fuels markets. We will develop and optimize homogeneous catalysts to break C-O bonds of the lignin fraction of lignocellulosic pyrolysate to produce specialty chemicals. Pyrolysis process improvements will be integrated at on- the-farm scale using an existing patent-pending dual fluidized bed, combustion-reduction integrated pyrolysis, unit (CRIPS) designed to mimic the fluid catalytic cracking (FCC) process. Using real process data from this scale up and optimized upgrading, an exergetic LCA will be performed to describe not only economics and greenhouse gas emissions but also resource depletion and loss of quality for distributed on-farm thermolysis; this will be the first complete economic, environmental, and social sustainability analysis for on-farm pyrolysis.
This is a sub-award for a NIFA funded Biomass Research & Development Initiative project (FarmBio3) for which ARS is the principal investigator. The collaborator has begun the project in January with literature review of platinum deoxygenation catalysis. The review revealed that ruthenium (Ru) and platinum (Pt) catalyst on alumina support (Ru/Al2O3, Pt/Al2O3) were the most active catalysts in deoxygenation of p-c resol, a model compound. Their research was geared towards understanding how deoxygenation occurs on Pt.
Prior to calculations of Pt reaction kinetics, a reaction network was generated. The generated network helps to identify and break down reaction steps and intermediates, and it helps to assess the size of the problem. The total number of elementary reactions necessary for modeling was calculated to be about 1600 reactions. Quantum calculations alone would take too much computational resources for this number of reactions. Thus, semi-empirical estimation methods are also needed in order to simulate reaction network. A challenge in this direction is that semi-empirical methods for aromatic molecules on surfaces do not currently exist.
Quantum calculation parameters need to be carefully assessed in order to strike a balance between accuracy and computational cost. The collaborator spent several weeks to understand the convergence properties for this system and optimize the computational parameters. The most stable adsorption structure of p-cresol on a platinum surface was identified to be bridge site. Assessing the thermochemistry of key hydrogenated and direct deoxygenated intermediates via Density Functional Theory in order to develop the thermochemistry needed for the entire reaction network is underway. The results of these efforts will be used to guide catalyst synthesis at the University of South Carolina, another FarmBio3 partner.