On-Site Research Publications

Search

Full Text Search: or Search by Author:

Search all NETL OSTI projects or search all projects on OSTI database


Over-voltage protection system and method
Creators: Chi, Song; Dong, Dong; Lai, Rixin
Date: 05/02/2017
Description: An over-voltage protection system includes an electronic valve connected across two terminals of a circuit and an over-voltage detection circuit connected across one of the plurality of semiconductor devices for detecting an over-voltage across the circuit. The electronic valve includes a plurality of semiconductor devices connected in series. The over-voltage detection circuit includes a voltage divider circuit connected to a break-over diode in a way to provide a representative low voltage to the break-over diode and an optocoupler configured to receive a current from the break-over diode when the representative low voltage exceeds a threshold voltage of the break-over diode indicating an over-voltage condition. The representative low voltage provided to the break-over diode represents a voltage across the one semiconductor device. A plurality of self-powered gate drive circuits are connected to the plurality of semiconductor devices, wherein the plurality of self-powered gate drive circuits receive over-voltage triggering pulses from the optocoupler during the over-voltage condition and switch on the plurality of semiconductor devices to bypass the circuit.


Mechanical membrane for the separation of a paramagnetic constituent from a fluid
Creators: Maurice, David
Date: 05/02/2017
Description: The disclosure provides an apparatus and method for the separation of a paramagnetic component from a mixture using a mechanical membrane apparatus. The mechanical membrane comprises a supporting material having a plurality of pores where each pore is surrounded by a plurality of magnetic regions. The magnetic regions augment a magnetic field on one side of the supporting material while mitigating the field to near zero on the opposite side. In operation, a flow of fluid such as air comprising a paramagnetic component such as O.sub.2 is directed toward the mechanical membrane, and the paramagnetic component is typically attracted toward a magnetic field surrounding a pore while dimagnetic components such as N.sub.2 are generally repelled. As some portion of the fluid passes through the plurality of magnetic apertures to the opposite side of the mechanical membrane, the mechanical membrane generates a fluid enriched in the paramagnetic component. Alternately, the magnetic field may act to repel the paramagnetic component while diamagnetic components such as N.sub.2 are generally unaffected and pass to the opposite side of the mechanical membrane.


US-UK Collaboration on Fossil Energy Advanced Materials: Task 2—Materials for Advanced Boiler and Oxy-combustion Systems(NETL-US)
Creators: Holcomb, Gordon; Tylczak, Joseph; Carney, Casey
Date: 04/19/2017
Description:


Method of CO and/or CO.sub.2 hydrogenation to higher hydrocarbons using doped mixed-metal oxides
Creators: Shekhawat, Dushyant; Berry, David A.; Haynes, Daniel J.; Abdelsayed, Victor; Smith, Mark W.; Spivey, James J.
Date: 03/21/2017
Description: A method of hydrogenation utilizing a reactant gas mixture comprising a carbon oxide and a hydrogen agent, and a hydrogenation catalyst comprising a mixed-metal oxide containing metal sites supported and/or incorporated into the lattice. The mixed-metal oxide comprises a pyrochlore, a brownmillerite, or mixtures thereof doped at the A-site or the B-site. The metal site may comprise a deposited metal, where the deposited metal is a transition metal, an alkali metal, an alkaline earth metal, or mixtures thereof. Contact between the carbon oxide, hydrogen agent, and hydrogenation catalyst under appropriate conditions of temperature, pressure and gas flow rate generate a hydrogenation reaction and produce a hydrogenated product made up of carbon from the carbon oxide and some portion of the hydrogen agent. The carbon oxide may be CO, CO.sub.2, or mixtures thereof and the hydrogen agent may be H.sub.2. In a particular embodiment, the hydrogenated product comprises olefins, paraffins, or mixtures thereof.


Chromia refractory brick with carbon treatment
Creators: Bennett, James P.; Kwong, Kyei-Sing
Date: 03/21/2017
Description: The disclosure provides a refractory brick system comprising a chromia refractory brick for operation in the slagging environment of an air-cooled gasifier. The chromia refractory brick comprises a ceramically-bonded porous chromia refractory having a porosity greater than 9% and having carbon deposits residing within the pores. The brick may be further comprised of Al.sub.2O.sub.3. The air-cooled gasifier generates a liquefied slag in contact with the refractory brick and generally operates at temperatures between 1250.degree. C. and 1575.degree. C. and pressures between 300 psi to 1000 psi, with oxygen partial pressures generally between 10.sup.-4 and 10.sup.-10 atm. The refractory brick performs without substantial chromium carbide or chromium metal formation in the low oxygen partial pressure environment. The inclusion of carbon without chromium carbide formation provides for significant mitigation of slag penetration and significantly reduced refractory wear.


Surface functionalization of metal organic frameworks for mixed matrix membranes
Creators: Albenze, Erik; Lartey, Michael; Li, Tao; Luebke, David R.; Nulwala, Hunaid B.; Rosi, Nathaniel L.; Venna, Surendar R.
Date: 03/21/2017
Description: Mixed Matrix Membrane (MMM) are composite membranes for gas separation and comprising a quantity of inorganic filler particles, in particular metal organic framework (MOF), dispersed throughout a polymer matrix comprising one or more polymers. This disclosure is directed to MOF functionalized through addition of a pendant functional group to the MOF, in order to improve interaction with a surrounding polymer matrix in a MMM. The improved interaction aids in avoiding defects in the MMM due to incompatible interfaces between the polymer matrix and the MOF particle, in turn increasing the mechanical and gas separation properties of the MMM. The disclosure is also directed to a MMM incorporating the surface functionalized MOF.


Improved Modeling of Naturally Fractured Reservoirs by Quantitatively Handling Flow Convergence into the Wellbore
Creators: Crandall, Dustin [National Energy Technology Lab. (NETL), Morgantown, WV (United States)]; Stadelman, Matthew [National Energy Technology Lab. (NETL), Morgantown, WV (United States)]
Date: 03/13/2017
Description:


The role of Sb in solar cell material Cu2ZnSnS4
Creators: Zhang, Xiaoli [Chinese Academy of Sciences, Hefei (China)] (ORCID:0000000222195705); Han, Miaomiao [Chinese Academy of Sciences, Hefei (China); Univ. of Science and Technology of China, Hefei (China)]; Zeng, Zhi [Chinese Academy of Sciences, Hefei (China); Univ. of Science and Technology of China, Hefei (China)]; Duan, Yuhua [National Energy Technology Lab. (NETL), Pittsburgh, PA (United States)]
Date: 03/03/2017
Description: In this paper, based on first-principles calculations we report a possible mechanism of the efficiency improvement of the Sb-doped Cu2ZnSnS4 (CZTS) solar cells from the Sb-related defect point of view. Different from Sb in CuInSe2 which substituted the Cu atomic site and acted as group-13 elements on the Cu-poor growth condition, we find out that Sb prefers to substitute Sn atomic site and acts as group-14 elements on the Cu-poor growth condition in CZTS. At low Sb concentration, SbSn produces a deep defect level which is detrimental for the solar cell application. At high Sb concentration, Sb 5s states form an isolated half-filled intermediate band at 0.5 eV above the valence band maximum which will increase the photocurrent as well as the solar cell efficiency.


Gasification Technologies, in Handbook of Climate Change Mitigation and Adaptation
Creators: Shadle, Lawrence; Breault, Ronald; Bennett, James
Date: 03/02/2017
Description:


Hydraulic fracturing system and method
Creators: Ciezobka, Jordan; Salehi, Iraj
Date: 02/28/2017
Description: A hydraulic fracturing system and method for enhancing effective permeability of earth formations to increase hydrocarbon production, enhance operation efficiency by reducing fluid entry friction due to tortuosity and perforation, and to open perforations that are either unopened or not effective using traditional techniques, by varying a pump rate and/or a flow rate to a wellbore.


Next >>

Search all NETL OSTI projects or Search All On Osti Database