Search NASA⌕ Search

SEARCH · Search NASA

Results for “Conversion methods”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,243 records · Page 69
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Graphene Quantum Dot Composites Embedded with CoZn Alloy Nanoparticles for Enhanced Oxygen Reduction and Evolution Reactions

Developing efficient and durable electrocatalysts for oxygen reduction (ORR) and oxygen evolution reactions (OER) is crucial for energy conversion technologies. In this study, core–shell graphene quantum dot (GQD) composites embedded with Co, Zn, and CoZn alloy nanoparticles were synthesized using a solid-state microwave synthesis method and systematically investigated for their electrochemical performance. The structural and compositional analyses confirm that the integration of transition metal nanoparticles enhances the electronic properties of GQDs, providing abundant active sites and facilitating charge transfer. Electrochemical characterization reveals that GQD-CoZn-3 (GQD:Co:Zn = 10.5:0.5:0.5) exhibits superior ORR and OER catalytic activities, achieving the highest current densities of 205 A g–1 and 102 A g–1 at 100 mV s–1, respectively. These performance values surpass those of pristine GQDs and single-metal (Co or Zn) embedded counterparts, emphasizing the strong synergistic effect between the CoZn alloy and the functionalized carbon framework. Impedance measurements further reveal a substantial reduction in charge-transfer resistance, while chronoamperometry tests demonstrate excellent catalytic stability and CO tolerance, highlighting the robustness of the core–shell GQD structure. These findings provide valuable insights into the design of advanced carbon-based electrocatalysts for energy applications.

Panda, Pradeep Kumar↗
DOE OSTI2019

Measurement of Physicochemical Properties of Lignin

Lignin is an essential cell wall component of lignocellulose. Unlike other major components such as cellulose and hemicellulose, lignin is a noncarbohydrate biopolymer and contributes to cell wall rigidity and hydrophobicity. Lignin’s unique properties contribute to the transportation of water and minerals in plants and protect against microbial attacks, while the latter property hinders the conversion of carbohydrates in lignocellulose. Also, its heterogeneity and structural complexity are major recalcitrance factors in biomass conversion. Various approaches (including genetically engineered plants, pulping, pretreatments, and fractionation processes) have been proposed to reduce and/or remove lignin for effective conversion of lignocellulose. Recently, interest in the biorefinery concept considers lignin as a potential feedstock in many applications; however, the technologies necessary to facilitate the economic production of many lignin-based products is still in its infancy. For the effective utilization of lignocellulose, understanding the physicochemical properties of lignin is the first and last step. It not only provides the key information about lignin structures in the original plant cell wall, conversion products, or residues, but also explains how the modification and/or conversion process affects lignin and biomass in general. Many different lignin characteristics, including physicochemical, morphological, and thermal properties, can be measured by diverse analytical techniques. This chapter introduces analytical methods that measure several essential physicochemical properties of lignin, such as molecular weights by gel permeation chromatography (GPC), quantitative and qualitative information of structural properties (interunit linkages and aromatic subunits) by one-dimensional and two-dimensional nuclear magnetic resonance (NMR), and hydroxyl group content by 31P NMR.

Yoo, Chang Geun↗
DOE OSTI2026

Unraveling design principles of protein landscapes in photosynthetic membranes in plant chloroplasts

The supramolecular organization of proteins within photosynthetic membranes is crucial for energy conversion in plants. Here, we introduce an analytical and computational pipeline that integrates high-resolution cryo–scanning electron microscopy, biochemical quantification, advanced Monte Carlo computer simulations, and statistical methods to elucidate the elusive protein landscapes of grana membranes in intact Arabidopsis leaves. Our integrated analysis challenges the prevailing view that particles on the exoplasmic fracture faces in freeze-fracture samples represent photosystem II exclusively. Instead, these particles also include cytochrome b 6 f complexes. Furthermore, our steric clash analysis demonstrates that stacked membranes contain a mixture of larger PSII supercomplexes (C 2 S 2 M 2 and C 2 S 2 ) in addition to a smaller complex (C 2 ). This suggests that in vivo PSII supercomplexes exist in an equilibrium distribution of differing sizes. Furthermore, we discovered that, although size exclusion effects govern the global protein arrangement, local packing exhibits orientational order indicative of lateral attractive protein-protein interactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Internal Standards for Quantitative Analysis of Chemical Warfare Agents by the GC/MS Method: Nerve Agents

General conditions and requirements for an internal standard useful in the determination of chemical warfare agents (CWAs) by the method of gas chromatography coupled with mass detection (GC/MS) were defined. The determination is based on a GC/MS analysis of a mixture of a CWA with an internal standard, conversion of the TIC chromatogram to a chromatogram extracted at a particular m / z ratio, and calculation of the CWA concentration from the internal standard concentration, response factor, and chromatographic peak areas. Available internal standards were identified, and they were verified for seven organophosphorus nerve-paralysing agents. Corresponding response factors were determined as a ratio of gradients of the linear functions of the peak area and compound concentration. Linearity, repeatability, and accuracy of the measurements were evaluated. The determination can be performed on all GC/MS systems of the Fire Rescue Service of the Czech Republic (FRS), where no CWA standards are available.

Capoun, Tomas↗
DOE OSTI2019

THF Co-Solvent Biomass Fractionation to Catalytic Fuel Precursors with High Yields (Final Report)

The overall goal of this project is to utilize the Co-Solvent Enhanced Lignocellulosic Fractionation (CELF) as a platform technology to realize transformation of real biomass feedstocks to fungible transportation fuels. CELF is a solvolysis method that seeks to break the cost barrier for biomass deconstruction so that high yield liquid intermediates from both sugars and lignin can be recovered for their subsequent catalytic conversion to fungible transportation fuels. It is important for the DOE EERE mission to focus on supporting platform technologies that enable greater end-to-end utilization of biomass whereby the co-development of both process and catalyst is streamlined. CELF is one of the most competitive platform technologies that uses multifunctional co-solvents THF and water to provide the cleanest intermediate product streams that can allow advanced catalysts to be developed on real feedstocks instead of model compounds. For this project, we developed a hybrid catalytic process that first applies CELF homogeneous catalysis to convert solid biomass to a liquid stream containing intermediate fuel precursors (FPs) such as furfural (FF) and 5-hydroxymethylfurfural (5-HMF). Afterwards, a second heterogeneous catalytic step was then applied to selectively hydrodeoxygenate (HDO) the FPs produced from biomass into gasoline blendstocks methylfuran (MF) and dimethylfuran (DMF). Concurrently, capitalizing on CELF’s efficient lignin extraction capabilities, we further explored production C9+ cyclic hydrocarbons from biomass lignin to improve overall process economics. For the first step, the CELF process was optimized to achieve yields of >95% for FF and >60% for HMF from the xylan and glucan fractions in poplar wood, respectively. For the second step, we created a patent-pending bifunctional Cu-Ni solid catalyst that is tolerant to real product streams from the CELF process and simultaneously produce MF and DMF blendstocks at >80% yields. To provide more market versatility, we further explored the production of 2-pentanol from MF and have achieved >70% yields. During this project’s three year period, we also developed a dynamically informed technoeconomic computer model that helped to guide key project decisions that allowed us to reach a final biofuel selling price (MFSP) of <$\$$3/GGE (gallon gasoline equivalent) and total biomass carbon utilization of 60%. We also determined that the MFSP in our model could be further reduced to below $\$$2/GGE if the value of the lignin-derived aromatic hydrocarbon fuels could be sold at diesel-range prices (>$\$$500/tonne). Our process model was designed to consume 288 tonnes per day of poplar wood chips with minor consumption of hydrogen to produce a range of fuel blendstocks suitable for use in the transportation sector. The project was successful in meeting DOE EERE program criteria for application of an all-catalytic biofuels process to achieve a biofuel selling price target of <$\$$3/GGE as well as to achieve a 60% reduction in greenhouse gas emissions (GHG) compared to conventional fossil petroleum processes. At project completion, the outlined catalytic process reported total utilization of up to 60% of the carbon found in biomass, rivaling more mature biological cellulosic ethanol technologies at a fraction of the fixed and operating costs. This project also resulted in 7 peer-reviewed publications, 2 provisional inventions, and 1 patent pending. NOTE: This public version of the document contains redacted text, tables, and figures as indicated within the document.

09 BIOMASS FUELS↗
DOE OSTI2019

Thermodynamics and Kinetics of Phase Transformations in Energy Materials (Final Report)

The primary goal of this program is to develop computational tools and methodology for enabling a shift from empirical trial-and-error driven materials discovery towards data and information technology driven design of materials with targeted functional properties. Both thermodynamic and kinetic factors need to be taken into account when designing new materials. Thermodynamics sets the necessary-but-not-sufficient conditions for the suitability of a particular material in a given application, while the kinetics controls the rates of microscopic processes and hence the performance in energy applications (e.g., power in energy storage, conversion efficiencies in solar cells and thermoelectrics, chemical activity in catalysis). The complexity of these phenomena makes computational design difficult, not least due to the lack of suitable theoretical methods and computational tools. To address these needs, we develop systematic, quantitatively accurate first-principles methods to address two important problems: (i) predict and optimize the thermodynamics of materials over a large composition and structure space, and (ii) model kinetic processes such as mass and heat transport in crystalline solids under non-equilibrium conditions. These tasks are addressed by combining high-throughput computation with automatic construction of accurate lattice models using mathematically rigorous methods of information theory, such as compressive sensing and Bayesian inference.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Evolution of Two-Phase High Explosive Reactive Flow [Slides]

Reactive hydrodynamics involve rapid conversion of reactants to products along a detonation wave and needs a closure rule: P-T equilibrium. To calculate P-T equilibrium, we use a root finding method, which can be a computational bottleneck. We evolve the guess for the root finder rather than using the previous value to reduce iterations. Evolving products volume fraction Φ p for an initial root finding guess does reduce root finding iterations and seems to give the best results immediately following a detonation wave (reducing root finding iterations from 5 to 2).

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1984

Theoretcial studies of solar-pumped lasers

A method of pumping a COhZ laser by a hot cavity was demonstrated. The cavity, heated by solar radiation, should increase the efficiency of solar pumped lasers used for energy conversion. Kinetic modeling is used to examine the behavior of such a COhZ laser. The kinetic equations are solved numerically vs. time and, in addition, steady state solutions are obtained analytically. The effect of gas heating filling the lower laser level is included. The output power and laser efficiency are obtained as functions of black body temperature and gas ratios (COhZ-He-Ar) and pressures. The values are compared with experimental results.

Harries, W. L.↗
NASA NTRS1996

Signal Processing and Calibration of Continuous-Wave Focused CO2 Doppler Lidars for Atmospheric Backscatter Measurement

Two continuous-wave(CW)focused C02 Doppler lidars (9.1 and 10.6 micrometers) were developed for airborne in situ aerosol backscatter measurements. The complex path of reliably calibrating these systems, with different signal processors, for accurate derivation of atmospheric backscatter coefficients is documented. Lidar calibration for absolute backscatter measurement for both lidars is based on range response over the lidar sample volume, not solely at focus. Both lidars were calibrated with a new technique using well-characterized aerosols as radiometric standard targets and related to conventional hard-target calibration. A digital signal processor (DSP), a surface acoustic and spectrum analyzer and manually tuned spectrum analyzer signal analyzers were used. The DSP signals were analyzed with an innovative method of correcting for systematic noise fluctuation; the noise statistics exhibit the chi-square distribution predicted by theory. System parametric studies and detailed calibration improved the accuracy of conversion from the measured signal-to-noise ratio to absolute backscatter. The minimum backscatter sensitivity is approximately 3 x 10(exp -12)/m/sr at 9.1 micrometers and approximately 9 x 10(exp -12)/m/sr at 10.6 micrometers. Sample measurements are shown for a flight over the remote Pacific Ocean in 1990 as part of the NASA Global Backscatter Experiment (GLOBE) survey missions, the first time to our knowledge that 9.1-10.6 micrometer lidar intercomparisons were made. Measurements at 9.1 micrometers, a potential wavelength for space-based lidar remote-sensing applications, are to our knowledge the first based on the rare isotope C-12 O(2)-18 gas.

Rothermel, Jeffry↗
DOE OSTI2024

UN-SiC TRISO Post Irradiation Examination Developmental Work

As part of efforts to strengthen INL?s post irradiation analysis capabilities with non-Advanced Gas Reactor (AGR) tristructural isotropic (TRISO) fuels, two developmental activities were conducted. The first activity was to determine how best to analyze uranium nitride TRISO fuel kernels using electron probe microanalysis, while the second activity focused on developing a method to deconsolidate TRISO fuel particles that have been encased in a silicon carbide matrix. Because these two activities were unrelated, they have been presented separately in this report. Initial EPMA analyses showed nitrogen contents that far exceeded the concentration expected for UN--a line compound. Further examination showed that current literature values for the mass absorption coefficient (MAC) for the N ka X-ray absorbed by U ranged from approximately 1600 to 9500, with most values tending toward 9500. Measuring UN with five different progressively increasing accelerating voltages followed by using the modeling program xMAC suggests the actual MAC is approximately 2115. Additional MAC modifications were required to produce reasonable analytical results. Because of the inaccuracies of necessary MAC coefficients, UN analysis via scanning electron microscopy (SEM) is likely to produce inaccurate results. This is because SEM software does not typically allow the user to alter MACs. Tests have been performed to examine the feasibility of an electrochemical technique to liberate irradiated TRISO fuel from a SiC matrix without damaging the outer pyrolytic carbon layer of the fuel particle. The method is performed by electrochemically exposing the SiC to magnesium metal forming Mg2Si and C. Following exposure, the small SiC samples showed slight mass increases with no evidence of conversion to Mg2Si and C nor obvious degradation of the SiC samples.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Transmissive concentrated photovoltaic module with cooling system

A spectrum splitting, transmissive concentrating photovoltaic (tCPV) module is proposed and designed for a hybrid photovoltaic-solar thermal (PV/T) system. The system may be able to fully utilize the full spectrum of incoming sunlight. By utilizing III-V triple junction solar cells with bandgaps of approximately 2.1 eV, 1.7 eV, and 1.4 eV in the module, ultraviolet (UV) and visible light (in-band light) are absorbed and converted to electricity, while infrared (IR) light (out-of-band light) passes through and is captured by a solar thermal receiver and stored as heat. The stored heat energy may be dispatched as electricity or process heat as needed. The tCPV module may have an overall power conversion efficiency exceeding 43.5% for above bandgap (in-band) light under a standard AM1.5D solar spectrum with an average concentration ratio of 400 suns. Passive and/or active cooling methods may be used to keep cells below 110° C. while transmitting >75% of out-of-band light to the thermal receiver, which may attain thermal energy capture at temperatures as high as 500° C. or more. A transparent active cooling system may improve the CPV module efficiency by about 1% (absolute) relative to a passive cooling system by reducing the maximum cell working temperature by about 16° C.

Escarra, Matthew David↗
DOE OSTI2017

Bioderived Muconates by Cross-Metathesis and Their Conversion into Terephthalates

Polyethylene terephthalate that is 100 % bioderived is in great demand in the market guided by the ever-more exigent sustainability regulations with the challenge of producing renewable terephthalic acid remaining. Renewable terephthalic acid or its precursors can be obtained by Diels–Alder cycloaddition and further dehydrogenation of biomass-derived muconic acid. The cis,cis isomer of the dicarboxylic acid is typically synthesized by fermentation with genetically modified microorganisms, a process that requires complex separations to obtain a high yield of the pure product. Moreover, the cis isomer has to be transformed into the trans,trans form and has to be esterified before it is suitable for terephthalate synthesis. To overcome these challenges, we investigated the synthesis of dialkyl muconates by cross-metathesis. The Ru-catalyzed cross-coupling of sorbates with acrylates, which can be bioderived, proceeded selectively to yield diester muconates in up to 41 % yield by using very low catalyst amounts (0.5–3.0 mol %) and no solvent. In the optimized procedure, the muconate precipitated as a solid and was easily recovered from the reaction medium. Analysis by GC–MS and NMR spectroscopy showed that this method delivered exclusively the trans,trans isomer of dimethyl muconate. The Diels–Alder reaction of dimethyl muconate with ethylene was studied in various solvents to obtain 1,4-bis(carbomethoxy)cyclohexene. The cycloaddition proceeded with very high conversions (77–100 %) and yields (70–98 %) in all of the solvents investigated, and methanol and tetrahydrofuran were the best choices. Next, the aromatization of 1,4-bis(carbomethoxy)cyclohexene to dimethyl terephthalate over a Pd/C catalyst resulted in up to 70 % yield in tetrahydrofuran under an air atmosphere. Because of the high yield of the reaction of dimethyl muconate to 1,4-bis(carbomethoxy)cyclohexene, no separation step was needed before the aromatization. This is the first time that cross-metathesis is used to produce bioderived trans,trans-muconates as precursors to renewable terephthalates, important building blocks in the polymer industry.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Roles of mineral matter in biomass processing to biofuels

Abstract Minerals in biomass have a significant impact on both biofuel quality and yield. This is especially true for current thermochemical biomass conversion processes. However, the roles of plant minerals in biochemical conversion have not been studied extensively, even though they are generally considered to lower the sugar yield because they reduce the feedstock proportion of carbohydrates. A successful strategic solution is thus necessary to overcome the challenges caused by the minerals in biomass, which include (1) decreased quality of biomass feedstocks; (2) reduction of process efficiency; and (3) reduction of the product quality and quantity from biomass conversion. This review summarizes the roles of plant minerals in a biorefinery, focusing on these key challenges. The discussion covers many issues related to plant minerals in biofuel production, including their sources, functions, and distribution in plant biomass, methods of characterizing them, their influence in a biorefinery, and the strategic handling required to manage their occurrence in biomass, based on reported studies. It could inspire better strategies to deal with the variance of mineral content in biomass feedstocks to increase process efficiency and reduce costs while supporting the concept of a circular bioeconomy. © 2023 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

09 BIOMASS FUELS↗
DOE OSTI2025

Microwave-Assisted Reforming of Tar Model Compound Using the Ni/La-CeO2 Catalyst

Gasification of solid feedstocks like coal, biomass and waste plastic produces syngas as a desired product. However, this process also produces an unwanted byproduct known as tar, which is a sticky compound consisting of a mixture of complex aromatic and polyaromatic hydrocarbons. The tar formed during the gasification process lowers the syngas yields and reduces the gasification efficiency by damaging the reactor. Therefore, it is essential to reduce the amount of tar formed during the gasification process. Catalytic reforming of tars is one way to mitigate tars. The goal of this research is to explore the possibility of microwave-assisted catalytic tar conversion to syngas. However, due to the complexity of the tar, toluene has been used as a model tar compound as it is stable and easy to handle. Ni-La/CeO2 was used as a catalyst for this study, which was synthesized by wet impregnation method. Fresh and spent catalysts were analyzed using various techniques to understand the reaction mechanism. The reaction was performed both under microwave (MW) and conventional (CV) reactor for comparison.

catalysis↗
DOE OSTI2023

A systematic multicriteria-based approach to support product portfolio selection in microalgae biorefineries

Here this work proposes and applies a sequential approach of objective methods to aid the decision-making process for the deployment of microalgae biorefineries. The strategy combines Multicriteria Decision Analysis (MCDA) and weight assignment methods to simultaneously consider technical, economic, and environmental criteria to (1) outrank the best bioproduct options from different biomass fractions present in microalgae biomass at different ratios (namely carbohydrates, lipids, and protein) and (2) define the most suitable biorefining pathways associated with specific pairings of microalgae strains and cultivation conditions. The first part of the assessment identified succinic acid, acrylic acid, and citric acid as the top-ranked bioproducts from carbohydrates, polyurethane from lipids, and thermoplastic extrusion co-feed from protein. The second step of the analysis determined that, when production of a hydrocarbon fuel is desired, the compositional profile of a strain is paramount in defining the biorefining setup that should be pursued. In summary, microalgae lipids should be sent to the production of hydrocarbon fuels if the ratio between neutral lipids and fermentable carbohydrates is higher than roughly 1, with carbohydrates and protein being converted to the higher-value products noted above. Finally, this result was corroborated through process simulations, which indicated superior economic and environmental metrics when strains are paired with suitable conversion pathways identified through MCDA based on their compositional profiles. The outcomes of this work provide clear, objective, guidelines for establishing the best biorefining approach for a large suite of biochemical compositions as a screening method prior to employing detailed process simulations alongside rigorous techno-economic and life-cycle assessments.

09 BIOMASS FUELS↗
DOE OSTI2019

Techno-Economic Analysis of Alternative Aqueous Phase Treatment Methods for Microalgae Hydrothermal Liquefaction and Biocrude Upgrading System

An economic analysis was conducted for an algae hydrothermal liquefaction (HTL) and biocrude upgrading system with alternative aqueous phase treatment methods. Using experimental data, three different methods were modeled and compared: 1) direct recycle HTL aqueous phase to the algae farm, 2) catalytic hydrothermal gasification (CHG), and 3) anaerobic digestion (AD). Direct recycle consumes the most natural gas because unlike AD and CHG, no methane is generated from the aqueous phase organics. However, direct recycle has the lowest cost compared to other two cases because it only requires the addition of pumps and buffer tankage related to aqueous phase recycle. The CHG and AD cases require significant capital and operating costs, which increase the minimum fuel selling price (MFSP) over the direct recycle case by 11% and 2.9%, respectively. CHG and AD respectively increase the conversion cost (excludes the cost to grow, harvest, and dewater algae) by 75% and 21%. Sensitivity analysis suggests that the key factors affecting the total cost of fuel production are the feedstock cost, biocrude yields, the plant scale, and the method of aqueous phase treatment.

Zhu, Yunhua↗
DOE OSTI2018

Surveying the Solar Power Gap: Assessing the Spatial Distribution of Emerging Photovoltaic Solar Adoption in the State of Georgia, U.S.A.

Despite a global push in the development and implementation of widespread alternative energy use, significant disparities exist across given nation-states. These disparities reflect both technical and economic factors, as well as the social, political, and ecological gaps between how communities see energy development and national/global policy goals. Known as the “local-national gap”, many nations struggle with fostering meaningful conversations about the role of alternative energy technologies within communities. Mitigation of this problem first requires understanding the distribution of existing alternative energy technologies at the local level of policymaking. To address the limitation of existing adoption trend analysis at the scale of local governance (e.g., county governments), this paper demonstrates a novel method for contextualizing solar technology adoption by using the State of Georgia in the United States as an exemplar. Leveraging existing work on the Gini Coefficient as a metric for measuring energy inequity, we argue these tools can be applied to analyze where gaps exist in ongoing solar adoption trends. As we demonstrate, communities that adopt solar tend to be concentrated in a few counties, indicating existing conversations are limited to a circumscribed set of social networks. This information and the model we demonstrate can enable focused qualitative analyses of existing solar trends, not only among high-adoption areas but within communities where little to no adoption has occurred.

14 SOLAR ENERGY↗
DOE OSTI2022

Catalytic Upgrading of Ethanol to C8+ Distillate Range Ethers via Guerbet Coupling and Etherification

Guerbet coupling followed by etherification is a two step process for conversion of ethanol into distillate range molecules. This involves first alcohol oligomerization, followed by acid-catalyzed dehydration. As we will show in this presentation, ethanol can be converted to higher linear and α-branched alcohols by C-C coupling reactions (ethanol oligomerization) as well as to high molecular weight esters by C-O coupling reactions with Cu/MgxAlOy (CuHT) catalysts. Alcohols may be converted to ethers via bimolecular dehydration in a subsequent step. We have identified more than 160 number of species in the products including alcohols, esters, aldehydes, ketonces, and olefins. Alcohols range from C4 to C10. Both alcohols and esters follow a Schulz-Flory chain growth model. We show the relationship between the catalyst properties (BET surface area, acid and base site count and Cu loading and synthesis method) and the performance in the reactions. We also show that physical mixtures of CuHT and HT can have similar product selectivity of low loading CuHT catalysts. The selectivity towards diesel fuel precursor compounds (hereafter ‘DFPC’) increased with conversion until reaching a plateau at high ethanol conversion (~70%). Alcohol selectivity follows a Schultz-Flory distribution at all studied conversions, and that adsorbed ethanol-derived species may undergo surface oligomerization into 1-butanol and higher alcohols before desorbing in a chain-growth mechanism. Zeolite catalysts convert the C4+ alcohols into C8+ ethers in both batch and continuous flow reactors. Selectivities of up to 80% to C8+ ethers at around 70% conversion using a single pass continuous flow system are able to be achieved. The final product feedstocks obtained from etherification have been used in technoeconomic (TEA) and lifecycle analysis (LCA), which indicate a reduction in greenhouse gas (GHG) emissions of 50% relative to conventional diesel. These final feedstocks are undergoing engine testing to elucidate the physiochemical properties and will be compared to diesel #2 ASTM standards as a reference and will serve as a basis to improve the final bio-diesel blendstocks from etherification.

Huber, George↗