Karl O. Albrecht

Process Design and Economics for the Conversion of Algal Biomass to Hydrocarbons: Whole Algae Hydrothermal Liquefaction and Upgrading

This report provides a preliminary analysis of the costs associated with converting whole wet algal biomass into primarily diesel fuel. Hydrothermal liquefaction converts the whole algae into an oil that is then hydrotreated and distilled. The secondary aqueous product containing significant organic material is converted to a medium btu gas via catalytic hydrothermal gasification.

Integrated process for the catalytic conversion of biomass-derived syngas into transportation fuels

Efficient synthesis of renewable fuels that will enable cost competitiveness with petroleum-derived fuels remains a grand challenge. In this paper, we report on an integrated catalytic approach for producing transportation fuels from biomass-derived syngas. This novel process represents an alternative to conventional fuel synthesis routes (e.g., Fischer–Tropsch, Methanol-to-Gasoline) that have drawbacks, particularly at the scale of biomass. Composition of the resulting hydrocarbon fuel can be modulated to produce predominantly middle distillates, which is constantly increasing in demand compared to gasoline fraction. In this process biomass-derived syngas is first converted over an Rh-based catalyst into a complex aqueous mixture of condensable C2+ oxygenated compounds (predominantly ethanol, acetic acid, acetaldehyde, ethyl acetate). This multi-component aqueous mixture then is fed to a second reactor loaded with a ZnxZryOz mixed oxide catalyst, which has tailored acid–base sites, to produce an olefin mixture rich in isobutene. The olefins then are oligomerized using a solid acid catalyst (e.g., Amberlyst-36) to form condensable olefins with molecular weights that can be targeted for gasoline, jet, and/or diesel fuel applications. The product rich in long-chain olefins (C7+) is finally sent to a fourth reactor required for hydrogenation of the olefins into paraffin fuels. Simulated distillation of the hydrotreated oligomerized liquid product indicates that ∼75% of the hydrocarbons (iso-paraffins and cyclic compounds) are in the jet-fuel range. Process optimization for the oligomerization step could further improve yield to the jet-fuel range. All of these catalytic steps have been demonstrated in sequence, thus providing proof-of-concept for a new integrated process for the production of drop-in biofuels. Overall, we demonstrate approximately 41% carbon efficiency for converting syngas into jet-range hydrocarbons. This unique and flexible process does not require external hydrogen and also could be applied to non-syngas derived feedstock, such as fermentation products (e.g., ethanol, acetic acid, etc.), other oxygenates, and mixtures thereof containing alcohols, acids, aldehydes and/or esters.

A Brief Literature Overview of Various Routes to Biorenewable Fuels from Lipids for the National Alliance for Advanced Biofuels and Bio-products (NAABB) Consortium

Renewable methods of producing transportation fuels are currently the focus of numerous large research efforts across the globe. Renewable fuel produced from algal lipids is one aspect of this research that could have profound implications on future transportation fuel requirements. However, technical challenges remain in several areas of algal-lipid-based fuels. These challenges include the identification and development of robust and productive algal species as well as extraction methods to recover the produced lipids. Not the least of these technical challenges is the conversion of the algae lipids to fungible fuels. This brief literature review focuses primarily on state-of-the-art “downstream” applications of producing fuel from fats and lipids, which can be applied to ongoing research with algae-derived lipids.

Qualitative Characterization of the Aqueous Fraction from Hydrothermal Liquefaction of Algae Using 2D Gas Chromatography with Time-of-flight Mass Spectrometry.

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in complex mixtures. It is often used to analyze gasoline, jet fuel, diesel, bio-diesel and the organic fraction of bio-crude/bio-oil. In most of those analyses, the first dimension of separation is non-polar, followed by a polar separation. The aqueous fractions of bio-crude and other aqueous samples from biofuels production have been examined with similar column combinations. However, sample preparation techniques such as derivatization, solvent extraction, and solid-phase extraction were necessary prior to analysis. In this study, aqueous fractions obtained from the hydrothermal liquefaction of algae were characterized by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry without prior sample preparation techniques using a polar separation in the first dimension followed by a non-polar separation in the second. Two-dimensional plots from this analysis were compared with those obtained from the more traditional column configuration. Results from qualitative characterization of the aqueous fractions of algal bio-crude are discussed in detail. The advantages of using a polar separation followed by a non-polar separation for characterization of organics in aqueous samples by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry are highlighted.

Whole Algae Hydrothermal Liquefaction: 2014 State of Technology

This report describes the base case yields and operating conditions for converting whole microalgae via hydrothermal liquefaction and upgrading to liquid fuels. This serves as the basis against which future technical improvements will be measured.

Rh-Based Mixed Alcohol Synthesis Catalysts: Characterization and Computational Report

The U.S. Department of Energy is conducting a program focused on developing a process for the conversion of biomass to bio-based fuels and co-products. Biomass-derived syngas is converted thermochemically within a temperature range of 240 to 330°C and at elevated pressure (e.g., 1200 psig) over a catalyst. Ethanol is the desired reaction product, although other side compounds are produced, including C3 to C5 alcohols; higher (i.e., greater than C1) oxygenates such as methyl acetate, ethyl acetate, acetic acid and acetaldehyde; and higher hydrocarbon gases such as methane, ethane/ethene, propane/propene, etc. Saturated hydrocarbon gases (especially methane) are undesirable because they represent a diminished yield of carbon to the desired ethanol product and represent compounds that must be steam reformed at high energy cost to reproduce CO and H2. Ethanol produced by the thermochemical reaction of syngas could be separated and blended directly with gasoline to produce a liquid transportation fuel. Additionally, higher oxygenates and unsaturated hydrocarbon side products such as olefins also could be further processed to liquid fuels. The goal of the current project is the development of a Rh-based catalyst with high activity and selectivity to C2+ oxygenates. This report chronicles an effort to characterize numerous supports and catalysts to identify particular traits that could be correlated with the most active and/or selective catalysts. Carbon and silica supports and catalysts were analyzed. Generally, analyses provided guidance in the selection of acceptable catalyst supports. For example, supports with high surface areas due to a high number of micropores were generally found to be poor at producing oxygenates, possibly because of mass transfer limitations of the products formed out of the micropores. To probe fundamental aspects of the complicated reaction network of CO with H2, a computational/ theoretical investigation using quantum mechanical and ab initio molecular dynamics calculations was initiated in 2009. Computational investigations were performed first to elucidate understanding of the nature of the catalytically active site. Thermodynamic calculations revealed that Mn likely exists as a metallic alloy with Rh in Rh-rich environments under reducing conditions at the temperatures of interest. After determining that reduced Rh-Mn alloy metal clusters were in a reduced state, the activation energy barriers of numerous transition state species on the catalytically active metal particles were calculated to compute the activation barriers of several reaction pathways that are possible on the catalyst surface. Comparison of calculations with a Rh nanoparticle versus a Rh-Mn nanoparticle revealed that the presence of Mn enabled the reaction pathway of CH with CO to form an adsorbed CHCO species, which was a precursor to C2+ oxygenates. The presence of Mn did not have a significant effect on the rate of CH4 production. Ir was observed during empirical catalyst screening experiments to improve the activity and selectivity of Rh-Mn catalysts. Thus, the addition of Ir to the Rh-Mn nanoparticles also was probed computationally. Simulations of Rh-Mn-Ir nanoparticles revealed that, with sufficient Ir concentrations, the Rh, Mn and Ir presumably would be well mixed within a nanoparticle. Activation barriers were calculated for Rh-Mn-Ir nanoparticles for several C-, H-, and O-containing transitional species on the nanoparticle surface. It was found that the presence of Ir opened yet another reactive pathway whereby HCO is formed and may undergo insertion with CHx surface moieties. The reaction pathway opened by the presence of Ir is in addition to the CO + CH pathway opened by the presence of Mn. Similar to Mn, the presence of Ir was not found to not affect the rate of CH4 production.

Optimization of Rhodium-Based Catalysts for Mixed Alcohol Synthesis – 2012 Progress Report

Pacific Northwest National Laboratory has been conducting research to investigate the feasibility of producing mixed alcohols from biomass-derived synthesis gas (syngas). In recent years, this research has primarily involved the further development of catalysts containing rhodium and manganese based on the results of earlier catalyst screening tests. Testing continued in FY 2012 to further improve the Ir-promoted RhMn catalysts on both silica and carbon supports for producing mixed oxygenates from synthesis gas. This testing re-examined selected alternative silica and carbon supports to follow up on some uncertainties in the results with previous test results. Additional tests were conducted to further optimize the total and relative concentrations of Rh, Mn, and Ir, and to examine selected promoters and promoter combinations based on earlier results. To establish optimum operating conditions, the effects of the process pressure and the feed gas composition also were evaluated.

Catalysis of Organic Reactions

This special issue of Topics in Catalysis is devoted to discussions of catalysis applied particularly to the preparation of organic compounds and documents the proceedings of the 24th Biennial Conference of the Organic Reactions Catalysis Society (ORCS), held in Annapolis, Maryland from April 15th through April 19th, 2012. ORCS seeks to advance practical applications of catalysis for making organic compounds by fostering discussions, providing opportunities for members to present their work, and facilitating dissemination of scientific knowledge. At the 24th meeting, we celebrated two Paul N. Rylander award winners. The Paul N. Rylander Award is sponsored by BASF and is awarded annually to researchers who have made significant contributions in the application of catalysis in organic reactions. The 2011 winner, Thomas A. Puckette of the Eastman Chemical Company, was honored for his contribution to low-pressure Rh hydroformylation reactions and the development of previously undiscovered ligands. The 2012 winner, Melanie S. Sanford of the University of Michigan, was honored for her work in Pd-catalyzed C–H activation reactions. The two awardees reflect the essence of ORCS. Professor Sanford, through basic research, has been opening new paths for industrially relevant compounds while diminishing the environmental impact of their manufacture. Dr. Puckette’s research has been in an industrial setting where he has specialized in pioneering new pathways for catalyst systems operating at commercial scale. Dr. Puckette’s research has focused on the development of ligands that, prior to his work, were carefully avoided to prevent poisoning. The connection between fundamental and applied research in furthering catalysis deployed throughout the world is the vision of ORCS. Bringing the two worlds together is what makes ORCS, as a society, unique. The 24th biennial conference was organized into six major symposia as follows: