United States Department of Energy

About: United States Department of Energy is a government organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Coal & Catalysis. The organization has 13656 authors who have published 14177 publications receiving 556962 citations. The organization is also known as: DOE & Department of Energy.

Regulated Emissions from Biodiesel Tested in Heavy-Duty Engines Meeting 2004 Emission Standards

Abstract: Biodiesel produced from soybean oil, canola oil, yellow grease, and beef tallow was tested in two heavy-duty engines. The biodiesels were tested neat and as 20% by volume blends with a 15 ppm sulfur petroleum-derived diesel fuel. The test engines were the following: 2002 Cummins ISB and 2003 DDC Series 60. Both engines met the 2004 U.S. emission standard of 2.5 g/bhp-h NO{sub x}+HC (3.35 g/kW-h) and utilized exhaust gas recirculation (EGR). All emission tests employed the heavy-duty transient procedure as specified in the U.S. Code of Federal Regulations. Reduction in PM emissions and increase in NO{sub x} emissions were observed for all biodiesels in all engines, confirming observations made in older engines. On average PM was reduced by 25% and NO{sub x} increased by 3% for the two engines tested for a variety of B20 blends. These changes are slightly larger in magnitude, but in the same range as observed in older engines. The cetane improver 2-ethyl hexyl nitrate was shown to have no measurable effect on NO{sub x} emissions from B20 in these engines, in contrast to observations reported for older engines. The effect of intake air humidity on NO{sub x} emissions from the Cummins ISB was quantified.more » The CFR NO{sub x}/humidity correction factor was shown to be valid for an engine equipped with EGR, operating at 1700 m above sea level, and operating on conventional or biodiesel.« less

Theoretical Predictions of Energetic Molecular Crystals at Ambient and Hydrostatic Compression Conditions Using Dispersion Corrections to Conventional Density Functionals (DFT-D)

Abstract: Theoretical predictions of the crystallographic properties of a series of 10 energetic molecular crystals have been done using a semiempirical correction to account for the van der Waals interactions in conventional density functional theory (termed DFT-D) as implemented in a pseudopotential plane-wave code. This series contains compounds representative for energetic materials applications, that is, hexahydro-1,3,5-trinitro-1,3,5-s triazine (α- and γ-RDX phases), 1,3,5,7-tetranitro-1,3,5,7-tetraaza-cyclooctane (β-, α-, and δ-HMX phases), 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL20) (e-, β-, and γ-HNIW phases), nitromethane (NM), trans-1,2,-dinitrocyclopropane, 1,2,3,5,7-pentanitrocubane (PNC), pentaerythritol tetranitrate (PETN), 2,4,6-trinitro-1,3,5-benzenetriamine (TATB), 2,4,6-trinitrotoluene (TNT-I phase), and 1,1-diamino-2,2-dinitroethylene (FOX-7), systems belonging to diverse chemical classes that encompass nitramines, nitroalkanes, nitroaromatics, nitrocubanes, nitrate esters, and amino-nitr...

A Literature Review of CO2, Natural Gas, and Water-Based Fluids for Enhanced Oil Recovery in Unconventional Reservoirs

Abstract: Primary oil recovery from fractured unconventional formations, such as shale or tight sands, is typically less than 10%. The development of an economically viable enhanced oil recovery (EOR) techni...

An intermediate-temperature solid oxide fuel cell with electrospun nanofiber cathode

Abstract: Lanthanum strontium cobalt ferrite (LSCF) nanofibers have been fabricated by the electrospinning method and used as the cathode of an intermediate-temperature solid oxide fuel cell (SOFC) with yttria-stabilized zirconia (YSZ) electrolyte. The three-dimensional nanofiber network cathode has several advantages: (i) high porosity; (ii) high percolation; (iii) continuous pathway for charge transport; (iv) good thermal stability at the operating temperature; and (v) excellent scaffold for infiltration. The fuel cell with the monolithic LSCF nanofiber cathode exhibits a power density of 0.90 W cm−2 at 1.9 A cm−2 at 750 °C. The electrochemical performance of the fuel cell has been further improved by infiltration of 20 wt% of gadolinia-doped ceria (GDC) into the LSCF nanofiber cathode. The fuel cell with the LSCF–20% GDC composite cathode shows a power density of 1.07 W cm−2 at 1.9 A cm−2 at 750 °C. The results obtained show that one-dimensional nanostructures such as nanofibers hold great promise as electrode materials for intermediate-temperature SOFCs.

Carbon dioxide sequestration by direct mineral carbonation: process mineralogy of feed and products

Abstract: Direct mineral carbonation was investigated as a process to convert gaseous CO2 into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, resulting in dissolution of the mineral and precipitation of magnesium carbonate (MgCO3). Optimum results were achieved using heat-pretreated serpentine feed material and a high partial pressure of CO2 (PCO2). Specific conditions include 155°C, PCO2 = 185 atm and 15% solids. Under these conditions, a 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Process mineralogy was utilized to investigate the appropriate feed characteristics, identify the process products and interpret the mineral dissolution and carbonate precipitation reaction paths.