Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Dimethyl Ether”

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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS2021

Sublimation of Laboratory Ices Millimeter/Submillimeter Experiment (SubLIME): Structure-Specific Identifications of Products from UV-photolyzed Methanol Ice

Submillimeter/far-IR spectroscopy was used to detect and quantify organic molecules sublimated after the ultraviolet photolysis (at 12 K) and warm-up (up to 300 K) of a methanol (CH3OH) ice sample. Eleven sublimated photoproducts were uniquely identified: carbon monoxide (CO), formaldehyde (H2CO), ketene (C2H2O), acetaldehyde (CH3CHO), ethylene oxide (CH2OCH2), vinyl alcohol (CH2CHOH), ethanol (CH3CH2OH), dimethyl ether (CH3OCH3), methyl formate (HCOOCH3), glycolaldehyde (HOCH2CHO), and acetone ((CH3)2CO). Two additional products were detected in the photolyzed ice by Fourier-transform infrared (FTIR) spectroscopy: carbon dioxide (CO2) and methane (CH4). The rotational temperatures and gas densities were calculated for the organics containing two or more C atoms via a rotation diagram analysis, and the gas-phase submillimeter/far-IR technique was used in tandem with mass spectrometry and FTIR spectroscopy of the ice during photolysis. The abundance ratios of the sublimated species (normalized to methanol) were compared to those observed in hot cores (Orion-KL, Sagittarius B2(N), and IRAS 16293-2422(B)) and in comets C/2014 Q2 (Lovejoy) and 67P/Churyumov–Gerasimenko.

K. M. Yocum↗
NASA NTRS2020

Development and Performance Verification of a TPC Polarimeter for High Energy X-rays

We present the first application of a time projection chamber polarimeter to measure high energy X-ray polarization above 10 keV. The polarimeter is designed based on the PRAXyS soft X-ray polarimeter. The sealed gas is changed to a gas mixture of 60% argon and 40% dimethyl ether at 1 atm to be sensitive to high energy X-rays. The polarimeter performance is verified with linearly polarized, monochromatic X-rays at a synchrotron radiation facility, KEK Photon Factory BL-14A. The measured modulation factors are 42.4±0.6%, 50.4±0.6%,and 55.0±0.6% at 12, 14, and 16 keV, respectively, and the measured polarization angles are consistent with the expected values at all energies.

Tomoshi Takeda↗
DOE OSTI2021

BETO 2021 Peer Review - Advanced Catalyst Synthesis and Characterization (ACSC) Project WBS 2.5.4.304; 303; 305

The Advanced Catalyst Synthesis and Characterization (ACSC) project, in close collaboration with the Chemical Catalysis for Bioenergy (ChemCatBio) Consortium enabling projects, CatCost, and the Engineering of Catalyst Scale-Up project, (1) provides fundamental insight into working catalysts leading to actionable recommendations for all of the ChemCatBio catalysis projects, (2) addresses overarching catalysis challenges central to the ChemCatBio Consortium, and (3) adapts and applies new synthesis methodologies and in situ/operando characterization capabilities to meet the evolving needs of the catalysis projects. The outcome is a transition from empirical catalyst development to rational design through the prediction of materials with targeted properties based on advanced characterization combined with computational modeling, and the synthesis of next generation catalysts with predicted structures that yield demonstrated improvements in catalytic performance. In FY18, the ACSC helped to demonstrate the utility of the complete catalyst and process development cycle for dimethyl ether to high-octane gasoline over metal-modified zeolite catalysts for the Upgrading of C1 Building Blocks project, and in FY21 will leverage capabilities, expertise, and computational models established for this effort to target next-generation catalysts for ethanol to distillates for the Upgrading of C2 Intermediates project with enhanced performance in half the time.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2024

SHOCK TUBE IGNITION STUDIES OF RENEWABLE DIESEL FUELS FOR MEDIUM AND HEAVY-DUTY TRANSPORTATION

Currently extensive research on alternative fuels is being conducted due to their increasing demand to reduce greenhouse emissions. One renewable fuel studied in this work is dimethyl ether (DME) blended with propane(C3H8) as a potential mixture for heavy-duty engines used in semi-trucks. The blend has the potential to drastically reduce particulate and greenhouse gas emissions compared to a conventional diesel engine operating under similar conditions. To develop the use of mixture, one must conduct detailed conceptual and simulation studies before progressing to detail studies in CFD, engine modifications, and live testing. For simulations, accurate high-fidelity chemical kinetic models are necessary. However, the validity of the chemical kinetic mechanism for operating conditions of a heavy-duty mixing-controlled compression (MCCI) engine was widely unknown until recent work presented here and published. In this work, we studied the ignition of DME and propane blends in a shock tube under MCCI engine conditions. Ignition delay time (IDT) gathered behind the reflected shock for DME-propane mixtures for heavy-duty compression ignition (CI) engine parameters. Testing was conducted for undiluted varieties spanning from temperatures of 700 to 1100 K at pressures ranging from 55 to 84 bar for various blends (100% CH3OCH3, 100% C3H8, 60% CH3OCH3/ 40% C3H8) of DME and propane were combusted in synthetic air (21% O2/ 79% N2). Several experiments were conducted at higher pressures (90-120 bar) to improve the model performance and accuracy. The ignition delay times (IDTs) were compared to recent mechanisms, including Aramco3.0, NUIG, and Dames et al. A common trend among the mechanisms was overpredicted experimental IDTs. Further studies were conducted by a sensitivity analysis using the Dames et al. model, and critical reactions sensitive to IDTs of DME-propane mixture near 60 bar are outlined. Chemical analysis was conducted on the NTC region to explain chemical kinetics which is critical for developing MCCI heavy duty engines.

Mohammed, Zuhayr Pasha↗
DOE OSTI2025

High Pressure DME-Driven Fractional Crystallizations

Rare Earth Elements (REEs), include the 15 lanthanides plus yttrium and scandium and are crucial for various technologies and applications. Their low concentrations in the earth's crust require alternative sources. This study explores antisolvent fractional crystallization (FC) using dimethyl ether (DME) under high pressures to extract REEs from secondary sources such as mining waste, coal byproducts, and e-waste. DME's properties, including its solubility in water, small molecular size, and high vapor pressure, make it an effective antisolvent that can be easily recovered and reused. The method involves pressurizing DME to 1000-2000 psi in a reaction chamber with the test solution, followed by sample collection and analysis using ICP-MS and ICP-OES. This approach aims to address the limitations of current extraction methods, such as high energy consumption, chemical usage, and waste production, offering a potentially more efficient and sustainable solution for REE extraction.

37 - INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL C↗
DOE OSTI2026

Effect of NO on DME-Methanol HCCI Combustion Using a Reduced Chemical Kinetics Mechanism

Methanol is an attractive fuel for the maritime sector due to its wide availability. Its direct use as a fuel, however, is accompanied by challenges such as high latent heat of vaporization and low cetane number. A potential solution to overcome the ignition properties of methanol could be through on-board generation of dimethyl ether (DME) via catalytic dehydration of methanol. The resulting mixture from dehydration can be mixed in with the intake air to generate a homogenous charge compression ignition (HCCI) preburn for subsequent direct injection (DI) mixing controlled compression ignition (MCCI) of neat methanol. Within that context, complementary experimental work found that the influence of combustion residuals on the heat release rate (HRR) was significant, specifically for residual NO. This finding motivated the present computational and kinetic evaluation of the effects of NO on the low (LTHR) and high (HTHR) temperature heat release rates. The strong influence of small quantities of NO on the combustion process of a DME/methanol/H2O mixture (low catalyst or reactor efficiency) necessitated a kinetics-based investigation into this phenomenon. A mechanism sourced from the existing literature with NO had 172 species and 1375 reactions, making it computationally expensive for use. Hence, a mechanism reduction effort was implemented, and a rate constant (k) tuning effort based on sensitivity analysis was needed to validate experimental results using a zero-dimensional engine model in Cantera. The reduced mechanism was able to successfully capture the negligible influence of NO addition on DME HCCI combustion, whereas an advancement in LTHR and HTHR for a DME/methanol/H2O mixture was kinetically confirmed. Reaction pathway analysis showed that addition of NO chemically counteracted the OH sink created by alcohols like methanol, increasing the effectiveness of DME ignition.

Tyrewala, Daanish [ORNL] (ORCID:0000000208599324)↗
DOE OSTI2026

Effect of NO on DME-Methanol HCCI Experimental Observations

Methanol is an attractive fuel for the maritime sector due to its wide availability. Its direct use as a fuel, however, is accompanied by challenges such as high latent heat of vaporization and low cetane number. A potential solution to overcome the ignition properties of methanol could be through on-board generation of dimethyl ether (DME) via catalytic dehydration of methanol. The resulting mixture from dehydration can be mixed in with the intake air to generate a homogenous charge compression ignition (HCCI) preburn for subsequent direct injection (DI) and successful ignition methanol at diesel–like timescales. However, if the preburn species are treated separately from the complete methanol MCCI approach the preburn heat release rate (HRR) phasing and behavior do not replicate the preburn behavior of the complete approach. Thus, the presence of the main methanol mixing controlled compression ignition (MCCI) combustion event influences the DME/methanol preburn kinetics. Specifically, it was found that trapped residual temperature alone was insufficient alone to be responsible for the observed differences, and that trace species concentrations of NO in the trapped residual gas also influenced DME/methanol kinetics increasing low temperature heat release (LTHR) magnitude and advancing high temperature heat release (HTHR) phasing. NO is not present in HCCI combustion of neat DME or DME/methanol blends nor is elevated gas temperature in the trapped residuals; both of which result in failure to accurately predict the HCCI combustion of DME/methanol blends when coupled with subsequent DI methanol MCCI. This work experimentally explores the effect of trapped residual temperature and NO on DME and DME/methanol HCCI combustion.

Jatana, Gurneesh [ORNL] (ORCID:0000000288903225)↗
DOE OSTI2024

Experimental study of mechanistic factors influencing solvent-driven fractional crystallization of calcium sulfate

To advance dimethyl ether-driven fractional crystallization (DME-FC), a more sustainable method of water treatment and mineral recovery, a range of chemical equilibria were measured. These include varying concentrations of miscible organic solvents (MOS) used to experimentally measure the solvent-induced solid-liquid equilibrium (SLE) of calcium sulfate (CaSO 4 ) in water. Seven MOS, including dimethyl ether (DME), acetonitrile (MeCN), 1,4-dioxane, tetrahydrofuran (THF), acetone, ethanol, and diethylamine, were screened to establish trends associated with molecular volume, functional groups, and physical properties. The effect of MOS on CaSO 4 removal differed at concentrations <0.15 mol fraction MOS; MOS with greater molecular volume (THF, 1,4-dioxane, and diethylamine) induced greater CaSO 4 precipitation on a per mole basis. The solvent-induced SLE for all MOS converged between 0.15 and 0.2 mol fraction MOS, reaching a CaSO 4 concentration consistent with a water to MOS hydration ratio of 5:1 to 6:1, which may correspond to the solvent generating a solution-based pseudo-clathrate structure with continuity within the solution. Finally, solution pseudo-clathrate structures provide a mechanistic basis for DME-FC.

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

Solvent-driven fractional crystallization for atom-efficient separation of metal salts from permanent magnet leachates

Abstract This work reports a dimethyl ether-driven fractional crystallization process for separating rare earth elements and transition metals. The process has been successfully applied in the treatment of rare earth element-bearing permanent magnet leachates as an atom-efficient, reagent-free separation method. Using ~5 bar pressure, the solvent was dissolved into the aqueous system to displace the contained metal salts as solid precipitates. Treatments at distinct temperatures ranging from 20–31 °C enable crystallization of either lanthanide-rich or transition metal-rich products, with single-stage solute recovery of up to 95.9% and a separation factor as high as 704. Separation factors increase with solution purity, suggesting feasibility for eco-friendly solution treatments in series and parallel to purify aqueous material streams. Staged treatments are demonstrated as capable of further improving the separation factor and purity of crystallized products. Upon completion of a crystallization, the solvent can be recovered with high efficiency at ambient pressure. This separation process involves low energy and reagent requirements and does not contribute to waste generation.

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

Anode Boosted Electrolyzer

The aim of this project is to develop an anode catalyst and anolyte delivery system in renewably powered flow-electrolyzers that utilize waste carbon dissolved in non-potable process water as the anolyte to lower the overall cell potential at which hydrogen is generated (Anode-Boosting) while simultaneously purifying a non-potable water source. This project spans several of the desired aspects in the Renewable Hydrogen Transportation Fuel Pathways of interest: it combines renewably sourced energy with waste hydrocarbons, leading to enhanced water-splitting and eventual delivery and distribution of hydrogen for use in fuel cell powered transportation. Deployment of an Anode-Boosted Electrolysis process will provide a significant improvement in the effective energy efficiency for the generation of hydrogen due to a reduced cell potential and the desirable removal of organic impurities in waste water, offering a route to generating clean hydrogen and clean(er) water.

08 HYDROGEN↗
DOE OSTI2022

Decontamination of Mixed Paper and Plastic Municipal Solid Waste Increases Low and High Temperature Conversion Yields

With the implementation of China’s Green Fence Policy and the following National Sword Policy, there is a need to divert previously accepted waste materials away from the landfill. Mixed plastic and paper wastes that are too contaminated to be economically recycled can be used for conversion into fuels and products. The effect of common contaminants present in waste streams must be determined to make municipal solid waste (MSW) a viable alternative to agricultural feedstocks for conversion. In this study, MSW was sourced from a dual stream materials recovery facility (MRF) in Emmet County, Michigan and characterized via mass balance. The most common contaminants in mixed paper and plastic were quantified and targeted for decontamination when mixed paper was explored for low temperature conversion pathways and plastics for high temperature conversion pathways. Ink, stickies, and plastic contamination were sorted out of the mixed paper stream and did not have an impact on sugar yields during enzymatic hydrolysis (EH). Although no improvement in yield was found, it was noted that copy paper within the mixed paper stream had an elevated pH and higher concentration of fermentation inhibitors, suggesting that intrinsic properties of some paper types may not be ideal for EH and fermentation conversion. Dilute alkaline pretreatment and mechanical refining of mixed paper increased the EH yield of mixed paper, suggesting this previously established process could be used as a decontamination method. “Dirt” and particulates were washed from mixed plastic using either an aqueous detergent or a non-aqueous chemical washing method. Liquid oil yields were increased during microwave assisted fast pyrolysis. All decontamination techniques met the cost target of less than $30/dry ton with plastic decontamination ranging from $18.16 to $24.81/dry ton. Because dilute alkaline pre-treatment and mechanical refining is considered part of the conversion process, the decontamination cost during feedstock preprocessing was considered $0/dry ton.

09 BIOMASS FUELS↗
NASA NTRS2013

Lifetime Estimation of a Time Projection Chamber X-ray Polarimeter

The Gravity and Extreme Magnetism Small Explorer (GEMS) X-ray polarimeter Instrument (XPI) was designed to measure the polarization of 23 sources over the course of its 9 month mission. The XPI design consists of two telescopes each with a polarimeter assembly at the focus of a grazing incidence mirror. To make sensitive polarization measurements the GEMS Polarimeter Assembly (PA) employed a gas detection system based on a Time Projection Chamber (TPC) technique. Gas detectors are inherently at risk of degraded performance arising from contamination from outgassing of internal detector components or due to loss of gas. This paper describes the design and the materials used to build a prototype of the flight polarimeter with the required GEMS lifetime. We report the results from outgassing measurements of the polarimeter subassemblies and assemblies, enclosure seal tests, life tests, and performance tests that demonstrate that the GEMS lifetime is achievable. Finally we report performance measurements and the lifetime enhancement from the use of a getter.

Dimethyl ether↗
DOE OSTI2022

MSW Decontamination: Methods to Improve Biofuel Yields

MSW is usually contaminated with a variety of undesirable materials (food, chemicals, glass, metal) that can impact downstream applications such as conversion to biofuels. This presentation will showcase two decontamination methods using either a detergent wash or an organic solvent extraction to demonstrate up to 30% increase in biofuel precursor yields for plastic and paper MSW. The economics of the two decontamination methods will also be presented.

09 BIOMASS FUELS↗
DOE OSTI2025

CMI Winter Meeting 2025 Presentation

Lanthanides are important to many technologies including magnets used in high efficiency traction motors. While common in the environment and industrial waste streams, lanthanides are often present at very low concentrations. This work demonstrates synergistic lanthanide recovery from an aqueous magnet leachate to single ppm concentrations using Na2SO4 addition and subsequent DME-FC treatment. It was found that combining DME-FC with low concentrations of Na2SO4 (~0.1 M) results in synergistic isolation of lanthanides while making use of Na2SO4, an excessive byproduct of hydrometallurgical metal production. Combined Na2SO4 + DME reduced lanthanide metal ion's (Pr, Nd, Sm, Gd, Dy, and Ho) solubilities by 1,000 - 25,000x with final concentrations ranging from 2 ppm to 200 ppm. This can be compared to 0.1 M Na2SO4 alone providing a 10 - 200x reduction and DME providing a 100 - 1,500x reduction in lanthanide solubilities. Final solution concentrations of lanthanides were 99.8% lower than what could not be achieved with either individual process. The results also reveal different periodic trends in the solubility reduction for DME and Na2SO4.

37 - INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL C↗
NASA NTRS2009

Electrolytes for Low-Temperature Operation of Li-CFx Cells

A report describes a study of electrolyte compositions selected as candidates for improving the low-temperature performances of primary electrochemical cells that contain lithium anodes and fluorinated carbonaceous (CFx) cathodes. This study complements the developments reported in Additive for Low-Temperature Operation of Li-(CF)n Cells (NPO- 43579) and Li/CFx Cells Optimized for Low-Temperature Operation (NPO- 43585), which appear elsewhere in this issue of NASA Tech Briefs. Similar to lithium-based electrolytes described in several previous NASA Tech Briefs articles, each of these electrolytes consisted of a lithium salt dissolved in a nonaqueous solvent mixture. Each such mixture consisted of two or more of the following ingredients: propylene carbonate (PC); 1,2-dimethoxyethane (DME); trifluoropropylene carbonate; bis(2,2,2-trifluoroethyl) ether; diethyl carbonate; dimethyl carbonate; and ethyl methyl carbonate. The report describes the physical and chemical principles underlying the selection of the compositions (which were not optimized) and presents results of preliminary tests made to determine effects of the compositions upon the low-temperature capabilities of Li-CFx cells, relative to a baseline composition of LiBF4 at a concentration of 1.0 M in a solvent comprising equal volume parts of PC and DME.

Smart, Marshall C.↗
DOE OSTI2021

A solid electrolyte interphase to protect the sulfurized polyacrylonitrile (SPAN) composite for Li–S batteries: computational approach addressing the electrolyte/SPAN interfacial reactivity

This study addresses the reactivity of multiple solvents and lithium bis(fluorosulfonyl)imide (LiFSI) at the interface with sulfurized polyacrylonitrile (SPAN) in multiple stages of lithiation via ab initio molecular dynamics simulations. Here, both ether 1,3-dioxolane (DOL) and dimethyl carbonate (DMC) proved stable on the lithiated SPAN surface regardless of the lithium content, meaning that neither of these species likely contributes to growing a solid electrolyte interphase (SEI) coating to protect the SPAN composite. Conversely, cyclic carbonates, ethylene carbonate (EC) and fluoroethylene carbonate (FEC) are shown to be very active. The EC reduction occurs only on a highly lithiated surface with a 3.0 Li/S molar ratio, the equivalent of the SPAN composite in an over-discharge regime with voltages close to 0.0 V vs. Li/Li + . The FEC reduction starts with a 2.0 Li/S molar ratio and above, suggesting that FEC could act as a useful additive in electrolyte formulations with EC. Both EC and FEC follow multiple reduction mechanisms to produce complex reduction products and LiF in the FEC case. We provide a mechanistic description for each detected decomposition path. The LiFSI salt also proves reactive against the lithiated SPAN surface. The FSI – defluorination is the dominant reduction path. However, the SO 2 NSO 2 F – and SO 2 NSO 2 2– species proved stable against S–N cleavage. This behavior makes the LiFSI salt a potential candidate for SPAN-based Li–S batteries because it produces LiF without releasing SO 2 .

25 ENERGY STORAGE↗
DOE OSTI2020

Localized High Concentration Electrolytes for High Voltage Lithium-Metal Batteries: Correlation between the Electrolyte Composition and Its Reductive/Oxidative Stability

We demonstrate a first-principles screening methodology as an effective tool to explore electrolyte formulations for the new generation of high energy density rechargeable batteries. We study the liquid structure and electronic properties in dilute electrolytes, high concentration electrolytes (HCE), and localized high concentration electrolytes (LHCE), with focus on electrolyte formulations based on lithium bis(fluorosulfonyl)imide (LiFSI), dimethyl carbonate (DMC), and bis(2,2,2-trifluoroethyl) ether (BTFE) as a diluent. We describe the solvation complexes in the dilute electrolyte and explore structural changes triggered by the increase in lithium salt concentration for HCEs and the diluent effects in LHCEs. In HCE formulations, there is a 4-fold coordination environment of lithium-ions as in the dilute electrolyte, but the number of lithium-ion interactions with O atoms from FSI- anions dominates. In these solutions, the ability of the FSI- anions to interact with multiple lithium-ions allows complex 3D network formation and influences the reductive/oxidative behavior of the electrolyte. Interestingly, in LHCEs, the BTFE diluent molecules do not change the 3D solution structure when diluting the HCE formulation from 5.49 to 3.83 M. However, there is a composition threshold where the structural and electronic behavior may change. We show that diluting the HCE electrolyte with BTFE down to 1.77 M breaks the three-dimensional solution structure into an island-like solvation complex. We relate these structural changes to the electronic properties of the electrolytes finding a causal relationship between the reductive/oxidative behavior and the lithium-oxygen interaction mechanisms in the solvated complexes. The coordination with lithium-ions lowers the electrolyte LUMO and HOMO levels: the higher is the number of interactions with lithium-ions, the more likely the solvent molecule, FSI- anion, or diluent molecule is to be reduced and the less likely it is to become oxidized. The evolution of the solvated ion structure in HCE and LHCE suggests a close connection to a corresponding change in the lithium-ion transport mechanisms for these electrolytes.

anions, molecules, oxygen, solvents, electrolytes↗