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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.

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Conversion of High-Solids Hydrothermally Pretreated Bioenergy Sorghum to Lipids and Ethanol Using Yeast Cultures

Glucose and xylose are the major sugars in cellulosic hydrolysates. The cellulosic sugars can be used for the production of biofuels and value-added bioproducts. In this study, lipid and ethanol were produced from bioenergy sorghum syrups using engineered yeasts. Here, bioenergy sorghum was hydrothermally pretreated at 50% solids loading in a continuous reactor system and mechanically refined sequentially using a burr mill to improve biomass accessibility for hydrolysis. Fed-batch enzymatic hydrolysis was conducted with 50% w/v solids loading to achieve 230 g/L sugar concentration. Different strains of Rhodosporidium toruloides were used to ferment sugars into lipids, and the highest lipid yield of 9.2 g/L was observed. The lipid yield was improved to 19.0 g/l by implementing a two-stage culture where once the sugars were exhausted in the first stage, the yeast was introduced into fresh hydrolysate without adding nitrogen. For ethanol production, the engineered Saccharomyces cerevisiae SR8ΔADH6 was utilized to coferment glucose and xylose. Additionally, the effects of nutrient media (YP, YNB/urea, and urea), cellulosic sugar concentration, and sulfite addition were investigated to optimize the ethanol yield from sorghum syrups. The optimal ethanol yield at 73.3% was obtained from the YNB/urea culture consisting of 34 g glucose/L and 17 g xylose/L.

09 BIOMASS FUELS↗
DOE OSTI2022

Ethanol Conversion to C 4+ Olefins over Bimetallic Copper- And Lanthanum-Containing Beta Zeolite Catalysts

We report ethanol conversion to C 4+ olefins remains a critical yet nonselective process for producing renewable middle distillates. Here, Cu–La/Beta catalysts composed of copper and lanthanum incorporated onto a dealuminated Beta support are reported for ethanol conversion to C 4+ olefins (73% selectivity, ~98% ethanol conversion, 623 K,<4% C 1 –C 3 hydrocarbons) which particularly favors C 5+ olefin formation (43% selectivity) as a distinction from the benchmarking Cu–Y/Beta catalyst. Monometallic Cu/Beta or La/Beta samples are insufficient to catalyze the C 4+ olefin formation and primarily form dehydration products (e.g., ethylene and diethyl ether), indicating the necessity of both Cu and La species for butene and C 5+ olefin formation. Increasing the bulk La loading at a fixed Cu content yields higher C 5+ olefins until the La/Cu molar ratio reaches 3.6. These findings indicate Cu–La/Beta as an effective ethanol conversion catalyst that facilitates multiple C–C bond formation events required for synthesizing C 5+ olefins (i.e., hexenes and octenes).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Achieving complete electrooxidation of ethanol by single atomic Rh decoration of Pt nanocubes

Significance Direct ethanol fuel cells are attracting growing attention as portable power sources due to their advantages such as higher mass-energy density than hydrogen and less toxicity than methanol. However, it is challenging to achieve the complete electrooxidation to generate 12 electrons per ethanol, resulting in a low fuel utilization efficiency. This manuscript reports the complete ethanol electrooxidation by engineering efficient catalysts via single-atom modification. The combined electrochemical measurements, in situ characterization, and density functional theory calculations unravel synergistic effects of single Rh atoms and Pt nanocubes and identify reaction pathways leading to the selective C–C bond cleavage to oxidize ethanol to CO 2 . This study provides a unique single-atom approach to tune the activity and selectivity toward complicated electrocatalytic reactions.

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

Knock-limited combustion of ethanol-, isobutanol-, and 2-methyl-3-buten-2-ol-gasoline blends in a direct-injected spark-ignition engine

Knock-limited combustion of alcohol-gasoline fuel blends was studied in a direct-injection spark-ignition engine. Ethanol, isobutanol (2-methyl-1-propanol), and methylbutenol (2-methyl-3-buten-2-ol) were splash-blended with a blendstock for oxygenate blending (BOB) gasoline. Ethanol was blended in fractions of 10%, 20%, and 30% by volume (E10, E20, and E30). Isobutanol and methylbutenol were blended to match the oxygen weight percentage of the ethanol blends, resulting in blends of 16%, 32%, and 49% (I16, I32, and I49) isobutanol by volume and 18%, 37%, and 56% (M18, M37, and M56) methylbutenol by volume. Neat BOB and gasoline primary reference fuels (PRF) with octane numbers (ON) of 87 (PRF87) and 100 (PRF100) were included for reference. The engine was operated at fixed speed, equivalence ratio, and injection timing while knock-limited spark advance was located across a range of intake pressures. Low-level alcohol blends E10 and M18 had similar knocking behavior and appeared to be slightly more knock-resistant than I16. For mid-level blends, E20 showed further improvement over I32 while M37 showed noticeably better knock resistance, able to match the knock-resistance of PRF100 for loads above 1000 kPa gross indicated mean effective pressure (GIMEP). For high-level blends, the difference between E30 and I49 was similar to their mid-level counterparts. However, M56 showed significant improvement over E30 and I49 throughout the entire range of loads tested. M56 exceeded the knock-resistance of PRF100 for loads above 700 kPa GIMEP. The improved knock-resistance combined with the increased volumetric energy density of methylbutenol resulted in improved fuel consumption and indicated efficiency. The overall results of this study indicate that the order of knock-resistance of these three alcohols, for direct-injection operation with injection during the intake stroke, is isobutanol < ethanol < methylbutenol when compared on an equal oxygen weight basis.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2022

Ethanol Blends: Providing a Renewable Fuel Choice

More than 21 million vehicles on U.S. roads are flexible-fuel vehicles (FFVs) as of August 2022. These vehicles can operate on either gasoline or blends of gasoline and ethanol up to E85 (a gasoline-ethanol blend containing 51% to 83% ethanol). As a renewable fuel, ethanol offers significant advantages. It is produced predominantly in the United States, made from home-grown feedstocks, and burns cleaner than gasoline.

ethanol, E85, flexible fuel vehicles↗
DOE OSTI2024

Unveiling Highly Sensitive Active Site in Atomically Dispersed Gold Catalysts for Enhanced Ethanol Dehydrogenation

Developing a desirable ethanol dehydrogenation process necessitates a highly efficient and selective catalyst with low cost. Herein, we show that the “complex active site” consisting of atomically dispersed Au atoms with the neighboring oxygen vacancies (Vo) and undercoordinated cation on oxide supports can be prepared and display unique catalytic properties for ethanol dehydrogenation. The “complex active site” Au-Vo-Zr 3+ on Au 1 /ZrO 2 exhibits the highest H 2 production rate, with above 37,964 mol H 2 per mol Au per hour (385 g H 2 $g^{-1}_{Au}$ h -1 ) at 350 °C, which is 3.32, 2.94 and 15.0 times higher than Au 1 /CeO 2 , Au 1 /TiO 2 , and Au 1 /Al 2 O 3 , respectively. Combining experimental and theoretical studies, we demonstrate the structural sensitivity of these complex sites by assessing their selectivity and activity in ethanol dehydrogenation. Our study sheds new light on the design and development of cost-effective and highly efficient catalysts for ethanol dehydrogenation. Fundamentally, atomic-level catalyst design by colocalizing catalytically active metal atoms forming a structure-sensitive “complex site”, is a crucial way to advance from heterogeneous catalysis to molecular catalysis. In conclusion, our study advanced the understanding of the structure sensitivity of the active site in atomically dispersed catalysts.

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

Glucose assimilation rate determines the partition of flux at pyruvate between lactic acid and ethanol in Saccharomyces cerevisiae

Engineered Saccharomyces cerevisiae expressing a lactic acid dehydrogenase can metab- olize pyruvate into lactic acid. However, three pyruvate decarboxylase (PDC) isozymes drive most carbon flux toward ethanol rather than lactic acid. Deletion of endoge- nous PDCs will eliminate ethanol production, but the resulting strain suffers from C 2 auxotrophy and struggles to complete a fermentation. Engineered yeast assimilating xylose or cellobiose produce lactic acid rather than ethanol as a major product with- out the deletion of any PDC genes. We report here that sugar flux, but not sensing, contributes to the partition of flux at the pyruvate branch point in S. cerevisiae express- ing the Rhizopus oryzae lactic acid dehydrogenase (LdhA). While the membrane glucose sensors Snf3 and Rgt2 did not play any direct role in the option of predominant product, the sugar assimilation rate was strongly correlated to the partition of flux at pyruvate: fast sugar assimilation favors ethanol production while slow sugar assimilation favors lactic acid. Applying this knowledge, we created an engineered yeast capable of simultaneously converting glucose and xylose into lactic acid, increasing lactic acid production to approximately 17 g L –1 from the 12 g L –1 observed during sequential consumption of sugars. This work elucidates the carbon source-dependent effects on product selection in engineered yeast.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Quantification of active sites in yttrium containing dealuminated Beta zeolites during conversion of ethanol and acetaldehyde to butadiene

Here, in this work, yttrium containing dealuminated Beta zeolites (Y/deAlBeta) were synthesized and characterized by various spectroscopic techniques to improve understanding of ethanol upgrading over these materials. Characterization results indicate yttrium atoms partially condense with framework silanol nests formed during dealumination of parent Al-Beta supports. Active sites for conversion of ethanol and acetaldehyde to butadiene were quantified on a series of Y/deAlBeta catalysts (0.1–10 wt% yttrium) via ex situ chemisorption and transmission Fourier transformed infrared (FTIR) spectroscopy measurements by first measuring the integrated molar extinction coefficient (IMEC) for pyridine bound to Lewis acidic yttrium sites. In situ titrations with pyridine demonstrate that the number of sites quantified by ex situ chemisorption IR is quantitatively similar to the number of sites that catalyze butadiene formation, which varies (from 0.05 to 0.35) across the series of catalysts. In situ pyridine titrations impact butadiene site time yields (STY), but not crotonaldehyde STY, indicating that a distribution of yttrium sites is present, and that discrete yttrium site types participate in distinct steps in the pathway from ethanol to butadiene. Apparent kinetic parameters including activation energies and reaction orders were measured, these suggest differences in reactant (or reactant-derived intermediate) surface coverages result in higher STYs (per mol Y or per Lewis acidic Y site) for samples with low Y loadings relative to those with higher Y loadings. Isotopic labeling experiments evince the existence of other kinetically relevant steps in addition to the crotonaldehyde transformation to crotyl alcohol. Together, these findings provide further guidance into the heterogeneities in site structures in yttrium-containing zeolites and their relevance for the various steps in the pathway from ethanol to C 4 products useful for production of sustainable aviation fuel and renewable butadiene.

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

Ethanol as a Renewable Building Block for Fuels and Chemicals

Three factors, i) the ethanol “blend wall”, which limits its market as a transportation fuel, ii) advances in production efficiency, and iii) feedstock diversification, could lead to excess ethanol at competitive prices. Those factors have already motivated a search for value-added derivatives (e.g., distillate fuels, olefins, and asymmetric amines). Siting small, low cost, flexible conversion facilities to process ethanol at or near the fermentation plant could encourage the growth of an enterprise. Decreasing the barriers to entry, matching supply and demand, and enhancing access to production incentives are enabling success factors. This review discusses the process chemistries that might be employed by such ethanol conversion facilities based on market prices. Finally, how these technologies might benefit from process intensification, and without the requirement of complex processing or large pressures or temperature gradients typically employed in conventional, large scale facilities.

09 BIOMASS FUELS↗
DOE OSTI2020

Ethanol Conversion over La 0.7 Sr 0.3 MnO 3–x (100): Autocatalysis, Adjacent O-Vacancies, Disproportionation, and Dehydrogenation

The mechanism for catalytic conversion of ethanol over La 0.7 Sr 0.3 MnO 3– x (100) surface to acetaldehyde and ethene was investigated. Pre-exposure temperature-programmed reaction (PE-TPR) experiments were performed in which ethanol was introduced to oxidized or reduced surfaces followed by heating. In particular, sequential PE-TPR experiments were conducted to incrementally and gradually reduce the surface. The products and their ratios were investigated as a function of surface reduction. The data show that acetaldehyde and ethene production is catalyzed with hydrogen abstraction and oxygen abstraction reactions occurring by intermediates in vacancies at various temperatures >400 K. Adsorption of acetaldehyde followed by a temperature-programmed reaction does not produce ethene, indicating that acetaldehyde is not an intermediate to ethene and that the hydrogen and oxygen abstraction from ethanol to ethene are decoupled steps. Further evidence for this mechanistic nuance was obtained using isotopically labeled ethanol (CD 3 CH 2 OH), which produces CD 3 CHO and CD 2 CH 2 . Additionally, the ratio of aldehyde production to alkene production increases with reduction, suggesting that aldehyde is produced from a disproportionation reaction between ethoxy species in adjacent O-vacancies, while ethene is produced from a dehydrogenation reaction with ethoxy species in vacancies without requiring adjacent O-vacancies. Counterintuitively, this finding indicates that the more oxygenated product (aldehyde vs ethene) is favored with more vacancies and that the net alcohol conversion is autocatalytic. Density functional theory calculations were able to find the previously unknown disproportionation pathway between ethoxies in adjacent O-vacancies, and kinetic Monte Carlo simulations support this interpretation by reproducing experimental selectivities. The activation energies for these pathways are estimated as 132 ± 10 kJ/mol for the disproportionation reaction (when occurring between ethoxies in adjacent vacancies) and as 148 ± 11 kJ/mol for the direct dehydrogenation reaction of an ethoxy in a vacancy. Based on these results, a mechanism with operative pathways based on elementary steps in O-vacancies is reported.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Mechanism for Acetone and Crotonaldehyde Production during Steam Reforming of Ethanol over La 0.7 Sr 0.3 MnO 3–x Perovskite: Evidence for a Shared C4 Aldol Addition Intermediate

Here a mechanistic study was conducted on the catalytic conversion of ethanol over La 0.7 Sr 0.3 MnO 3–x perovskite catalysts in the presence and absence of water. The study sought insights into the path of C–C coupling toward acetone and crotonaldehyde and also into clarifying whether the lack of previous reports of C–C coupling over La 0.7 Sr 0.3 MnO 3–x (100) could be due to a “pressure gap”. Several types of experiments were performed at 400–800 K: flow experiments with a torr range reactant gas flown over La 0.7 Sr 0.3 MnO 3–x powders; ultra-high vacuum experiments with continuous gas exposures to a La 0.7 Sr 0.3 MnO 3–x (100) single-crystal sample; and torr range continuous gas exposures to a La 0.7 Sr 0.3 MnO 3–x (100) single-crystal sample. When ethanol and water were flown over La 0.7 Sr 0.3 MnO 3–x powders at 400–800 K, the products detected were ethene, acetaldehyde, acetone, crotonaldehyde, CO, CO 2 , and H 2 . Acetone was catalytically produced over both the La 0.7 Sr 0.3 MnO 3–x powder and the La 0.7 Sr 0.3 MnO 3–x (100) single-crystal sample at temperatures of 700–800 K when reaction conditions were on the order of 1 Torr of reactant gas and with an excess of water relative to ethanol (1 ethanol/9 water). Isotopic labeling with deuterium was used to gain insights into the C–C coupling reaction mechanism and paths in species with three and four carbons (C 3 and C 4 species). Additionally, steady-state isotopic transient kinetic analysis (SSITKA) experiments + simulations using carbon labeling of the ethanol feed were performed. Three mechanistic paths were considered for the C–C coupling step: the first two paths, A and B, involve coupling between two intermediates which are both in oxygen vacancies; and the third path, C, involves coupling between one intermediate in an oxygen vacancy and one intermediate outside of an oxygen vacancy. The results suggest that the dominant path to the C 3 product, acetone, depends on the conditions. The less active path (attributed to path A or B) occurs at 600–700 K and involves coupling between two irreversibly bound species. The more active path (attributed to path C) requires an excess of water, becomes dominant at 600–800 K, and involves coupling between one irreversibly bound species and one reversibly bound species. Based on these various observations from experiments and simulations, an elementary step is proposed for acetone formation involving a previously unreported C 4 transition state that is formed after aldol addition. Density functional theory calculations were performed based on this hypothesis, and it confirmed that this specific and previously unreported aldol addition path to acetone does exist and that this path consistent with the experimental data. In this path, C–C formation occurs to create a C 4 intermediate that is bound to an oxygen vacancy, then a hydrogen transfer with C–C bond breaking occurs that results in the production of the acetone molecule. The proposed mechanism is also consistent with the experimental observation that acetone formation has a greater than first-order dependence on the water vapor pressure.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Controlling Bacterial Contamination During Fuel Ethanol Fermentation Using Thermochemically Depolymerized Lignin Bio-Oils

Lactic acid bacteria (LAB) contamination during fuel ethanol fermentation can lead to significant economic loses. To circumvent this, fuel ethanol plants add antibiotics prophylactically, but their overuse has resulted in the emergence of antibiotic-resistant LAB strains. Lignin is a sustainable biopolymer that can be found as a waste product from lignocellulosic biorefineries. Technical lignins and their smaller phenolic subunits have been shown to exhibit broad-spectrum antimicrobial properties, but there is a lack of demonstrations of lignin derivatives with highly selective properties in the literature. Here, corn stover lignin from a biorefinery was oxidatively depolymerized using an environmentally benign organic oxidant, peracetic acid, into a bio-oil that has selective antimicrobial properties against LAB and not yeasts. The resulting bio-oil demonstrated up to 90% inhibition of commercially sampled LAB (including antibiotic-resistant strains) at 4 mg ml-1 with no inhibition against an industrial yeast strain. These antimicrobial properties of the bio-oil are attributed to larger unidentified lignin oligomers, compared to monolignols, that have a membrane damaging mode of action. Using the bio-oil (4 mg ml-1) during simultaneous saccharification and fermentation (SSF) of raw corn starch showed no inhibition of enzymatic activity, and in LAB contaminated fermentations the bio-oil treatments showed an 8% increase in ethanol yields at higher bacterial contamination ratios (l : 100 yeast to LAB, CFU per ml). This study illustrates the efficacy of using lignin bio-oil as an antibiotic replacement during fuel ethanol fermentation and demonstrates the highly selective antimicrobial properties of lignin oligomers, which creates a viable lignin valorization strategy for biorefineries.

bio-oil↗
DOE OSTI2021

Uncovering the active sites and demonstrating stable catalyst for the cost-effective conversion of ethanol to 1-butanol

We report the recent emergence of a robust renewable ethanol industry has provided a sustainable platform molecule toward the production of value-added chemicals and fuels; what is lacking now are viable conversion processes from ethanol that can displace the current production pathways from non-renewable pathways. Here in the work, we demonstrate the highly selective conversion of ethanol to higher alcohols over low copper loaded MgAl mixed oxide catalysts, with 50% improvement in higher alcohol yields over the current state of the art. At these copper concentrations, atomically dispersed Cu +1 were found to be stable even at highly reductive conditions and highly active towards higher alcohol products (e.g. butanol, hexanol) while suppressing side reaction pathways and leading to extended lifetimes of over 150 hours time on stream. Technoeconomic analysis conducted based on these experimental results demonstrate that this catalytic system is cost-competitive with the conventional process. This marks significant progress in the development of Guerbet coupling of ethanol as a viable renewable process and offers a pathway toward sustainable chemical and fuel production.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

One-pot ethanol production under optimized pretreatment conditions using agave bagasse at high solids loading with low-cost biocompatible protic ionic liquid

Agave bagasse (AG) is a potential bioenergy feedstock due to its high biomass productivity, even in semiarid lands. In particular, ionic liquid (IL) pretreatment using aprotic ILs (AILs) has greatly reduced AG recalcitrance towards downstream processing by lowering lignin content and achieving high sugar yields. However, AIL's low biocompatibility towards enzymes and bacteria combined with the high initial cost has limited further development of this technology. In a wash-free one-pot (OP) ethanol conversion process, the evaluation of AG pretreatment with a biocompatible low-cost protic IL (PIL), 2-hydroxyethylammonium acetate ([2-HEA][OAc]) was achieved, where PIL pretreatment was followed by enzymatic saccharification, then ethanol fermentation in a single vessel. The pretreatment conditions were optimized using a central composite design to enable high sugar conversion at low PIL content. Under optimized pretreatment conditions (160 °C, 60% IL loading and 1.5 h), a yield of 132 kg of ethanol per Ton of untreated biomass was estimated using high solids loading (30% solids loading) under a PIL-OP scheme. High lignin removal (>50%), a decreased cellulose crystallinity, and high glucan conversion (>85%) were achieved with PIL-pretreated AG comparable to yields obtained in an AIL-AG pretreated sample using 1-ethyl-3-methyl-imidazolium acetate ([C 2 C 1 Im][OAc]). Here, these results using [2-HEA][OAc] demonstrate the potential of AG in an OP scheme with improved total ethanol yields paving the way towards a more feasible IL-based biorefinery.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Insights into the mechanism of electrochemical chloride oxidation in ethanol from X-ray photoelectron spectroscopy, quiescent solution voltammetry, and rotating ring-disk electrodes

The wide availability of bio-derived alcohols provides the impetus to develop processes that convert them to valuable chemicals. The chloride ion is a redox mediator for electrocatalytic ethanol oxidation to 1,1-diethoxyethane (1,1-DEE) through an ethyl hypochlorite (EtOCl) intermediate, and this paper describes the chloride oxidation reaction (COR) to EtOCl on a glassy carbon (GC) electrode. Voltammetry measurements on a GC electrode in inert acetonitrile solvent combined with ex situ X-ray photoelectron spectroscopy (XPS) establish a Volmer step, where chloride ion from solution chemisorbs and is oxidized. In reactive ethanol solvent, ethanol adsorbs, and analyzing the current response in an LSV experiment supports a two-electron-transfer to form EtOCl, with chemisorption of the regenerated chloride. Koutecký–Levich (K–L) analysis on a rotating ring disk electrode (RRDE) shows that the kinetic rate constant of the COR in ethanol is on the order of 10 −8 cm s −1 , which is five orders of magnitude faster than the direct alcohol oxidation reaction in a kinetically limited regime. This hydrodynamic approach in understanding the electrochemistry of this non-aqueous system extends the possibilities for mediated electrocatalysis in neat alcohol solvents.

Van Daele, Ryan D. [University of Michigan, Ann Ar↗
DOE OSTI2023

Data for Glucose Assimilation Rate Determines the Partition of Flux at Pyruvate Between Lactic Acid and Ethanol in Saccharomyces cerevisiae

Engineered Saccharomyces cerevisiae expressing a lactic acid dehydrogenase can metabolize pyruvate into lactic acid. However, three pyruvate decarboxylase (PDC) isozymes drive most carbon flux toward ethanol rather than lactic acid. Deletion of endogenous PDCs will eliminate ethanol production, but the resulting strain suffers from C2 auxotrophy and struggles to complete a fermentation. Engineered yeast assimilating xylose or cellobiose produce lactic acid rather than ethanol as a major product without the deletion of any PDC genes. We report here that sugar flux, but not sensing, contributes to the partition of flux at the pyruvate branch point in S. cerevisiae expressing the Rhizopus oryzae lactic acid dehydrogenase (LdhA). While the membrane glucose sensors Snf3 and Rgt2 did not play any direct role in the option of predominant product, the sugar assimilation rate was strongly correlated to the partition of flux at pyruvate: fast sugar assimilation favors ethanol production while slow sugar assimilation favors lactic acid. Applying this knowledge, we created an engineered yeast capable of simultaneously converting glucose and xylose into lactic acid, increasing lactic acid production to approximately 17 g L−1 from the 12 g L−1 observed during sequential consumption of sugars. This work elucidates the carbon source-dependent effects on product selection in engineered yeast.

Conversion↗
DOE OSTI2022

Initial Engineering and Design for CO 2 Capture from Ethanol Facilities

The Energy & Environmental Research Center, in partnership with the U.S. Department of Energy (DOE) and North Dakota ethanol producer Red Trail Energy, LLC (RTE) and with technical support from Trimeric Corporation and the KLJ engineering firm, completed an initial engineering design (IED) for a hybrid capture system to estimate associated costs for retrofitting the operational RTE ethanol plant. The project goal supports the DOE objective to achieve negative emissions using commercially available technologies to attain Technology Readiness Level 6+ from a facility emitting >100,000 tonnes of carbon dioxide (CO 2 ) annually. The RTE CCS (carbon capture and storage) Project is currently operating a CO 2 capture facility, adjacent to the RTE ethanol facility in western North Dakota, and injecting the CO 2 more than a mile below RTE property for permanent storage. This novel hybrid capture system would process about 310,000 tonnes of CO 2 annually for the RTE host site and includes CO 2 capture and compression from bioprocessing as well as capturing CO 2 produced from natural gas boilers. The bioprocessing capture process, based on past RTE studies investigating ammonia liquefaction technology with CO 2 produced from natural gas boilers captured utilizing chemical absorption with amine, was shown to be technically feasible for the RTE site. Activities conducted to support the project goal included 1) designing a hybrid capture system using CO 2 emissions from both bioprocessing and heat production at the host site facility; 2) conducting a pre-front-end engineering and design analysis of the hybrid capture system to include environmental health and safety, a constructability report, identification of permits, and corporate approvals; and 3) performing a techno-economic assessment in accordance with DOE’s methodology, as demonstrated by the bituminous baseline study. In addition, a life cycle assessment (LCA) was completed for the RTE site to estimate the carbon life cycle for ethanol-CCS implementation using the designed hybrid capture system to determine potential for net-negative carbon emissions. Results of the IED showed the hybrid system to be technically viable, with a moderate estimated cost of $55/tonne CO 2 captured for the hybrid system. The cradle-to-gate LCA showed preliminary net-negative carbon emissions potential anticipated from implementing a hybrid CCS system at a commercial scale. Recommended next steps toward potential implementation include hybrid capture system demonstration testing for detailed engineering and LCA model comparisons with low-carbon fuel incentive programs for financial support.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2020

Single-reactor conversion of ethanol to 1-/2-butenes

A simplified processes for producing desired chemicals such as butenes from feedstock mixtures containing ethanol. In one set of embodiments this is performed in a single step, wherein a feed containing ethanol in a gas phase is passed over an acidic metal oxide catalyst having a transition metal dispersion of at least 5% on a metal oxide support. The ethanol content of the feedstock mixture may vary from 10 to 100 percent of the feed and in those non-eat applications the ethanol feed may contain water.

09 BIOMASS FUELS↗