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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 1,009 records · Page 56
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

System and method and apparatus for maintaining a pressure balance in a solids flow loop and for controlling the flow of solids therethrough

A system includes a standpipe for receiving a flow of solids therethrough, the standpipe having at least one inlet configured to receive a gas for decreasing a solids-to-gas ratio of the flow, a sealpot having an inlet fluidly coupled to the standpipe and an outlet fluidly coupled to a riser, the sealpot being configured to fluidize the solids received from the standpipe and to transport the solids to the riser, and a drain device fluidly coupled to an outlet in the standpipe, the outlet being located upstream from the inlet of the sealpot. The drain device is configured to remove the excess gas from the flow of solids within the standpipe to increase the solids-to-gas ratio of the flow prior to the solids entering the sealpot.

42 ENGINEERING↗
DOE OSTI2018

Sealpot and method for controlling a solids flow rate therethrough

A sealpot for a combustion power plant includes a downcomer standpipe which receives solids of the combustion power plant, a bed including a first end and a second opposite end, the first end connected to the downcomer standpipe, a discharge standpipe disposed at the second opposite end of the bed, and an orifice plate disposed between the bed and the discharge standpipe separating the discharge standpipe from the bed. The orifice plate includes apertures disposed at a height above the bed which allow transport of fluidized solids and gas through the orifice plate.

42 ENGINEERING↗
DOE OSTI2015

Design of a Commercial Scale Oxy-Coal Supercritical CO2 Power Cycle

This presentation provides an overview of NETL’s analyses of the supercritical CO2 (SCO2) recompression Brayton cycle for application to commercial scale power plants with CO2 capture. This cycle has the potential to achieve over 50% efficiency due to the recuperation of heat from the SCO2 turbine exhaust, while the high SCO2 density may yield reductions in plant footprint and capital cost. Prior work has found that a circulating fluidized bed (CFB) with enhanced combustion air preheating would be a suitable indirect heat source for a SCO2 power cycle. This work investigates several options for efficiently integrating an oxy-fired CFB with an indirect SCO2 cycle, including thermal integration with the air separation unit, and utilization of combustor exhaust heat to thermally balance the low temperature recuperator. The sensitivity of plant performance to various cycle parameters is investigated, and the effect of design choices on the plant’s capital cost is discussed.

Weiland, Nathan↗
DOE OSTI2017

Overview and Systems Studies of Supercritical CO2 Power Cycles

<span>This seminar discusses both indirect and direct-fired supercritical CO2 (sCO2) power cycles, briefly reviews the status of pilot plants under development for each of these cycles, and discusses NETL&rsquo;s systems studies of coal-fueled commercial-scale sCO2 plants with carbon capture and storage (CCS).&nbsp; Indirect sCO2 systems studied include an oxy-fired circulating fluidized bed heat source coupled to various sCO2 power cycles. &nbsp;The direct-fired sCO2 cycle design is thermally integrated with a Shell gasifier to efficiently burn syngas within the oxy-combustor of the sCO2 cycle. &nbsp;The performance and cost analyses of these plants are discussed, as well as comparisons to alternative cycles with CCS.&nbsp; Results show that coal-fueled sCO2 plants of either type can exceed 40% HHV plant efficiency with CCS, and have a reduced cost of electricity relative to other cycles.&nbsp; Other cycle configurations that offer further improvements in plant performance and cost-effectiveness are also discussed.</span>

Weiland, Nathan↗
DOE OSTI2014

Oxycombustion in transport oxy-combustor

A pressurized transport oxy-combustor with different configurations is disclosed. Substantially pure oxygen is fed to the transport oxy-combustor under pressure to combust fossil fuels, generating steam for power generation. The end product is the flue gas containing substantially pure CO2 after moisture condensation. The low excess oxygen necessary to achieve complete combustion in the combustor is scavenged by adding another fuel so that substantially all oxygen fed to the combustor is completely consumed. The capability to operate the transport oxy-combustor as a circulating fluidized bed combustor at very high solids circulation rates makes it unnecessary to use recycled CO2 or flue gas as a means to moderate and control the combustion temperature. The temperature in the combustor is effectively controlled by relatively cooler circulating solids that enter the combustion zone. A small amount of CO2 is recycled for aeration and to convey solids fuel to the combustor.

Vimalchand, Pannalal↗
DOE OSTI2019

Catalytic Upgrading of Biomass Pyrolysis Vapors at Bench Scale with Pt/TiO2

Vapor phase upgrading can produce a liquid of lower oxygen and higher energy density than can fast pyrolysis alone. Therefore, it is anticipated that catalytic pyrolysis followed by a single stage of hydrotreating will be a more cost-effective route to hydrocarbon fuels than fast pyrolysis with multiple-stage or more-severe hydrotreating. To this end, a bench-scale bubbling fluidized bed pyrolyzer was operated at 150 g/h feed rate of pine flour with a 100 g fixed-bed catalytic upgrader. A 0.5% Pt/TiO2 catalyst produced a lower oxygen (< 20%) liquid at 40% carbon efficiency at 400 degrees C and biomass-to-catalyst ratio (B:C) of 3 for numerous cycles. The catalyst was regenerated and reused by oxidation with air and reduction with hydrogen. The oxidation and reduction times were reduced to 2 h and 1 h respectively without compromising performance or catalyst temperature control. Increasing the pyrolysis temperature from 500 degrees C to 550 degrees C allowed operation at B:C greater than 3 at comparable performance. Performance was generally similar to 2% Pt/TiO2 but at reduced catalyst cost. Projected costs are < $4/gallon of gasoline blendstock. Responses to other parameter changes and prospects for further improvements will be discussed.

09 BIOMASS FUELS↗
DOE OSTI2019

Catalytic Upgrading of Biomass Pyrolysis Vapors at Bench Scale with Platinum on Titania

Vapor phase upgrading can produce a liquid of lower oxygen and higher energy density than can fast pyrolysis alone. Therefore, it is anticipated that catalytic pyrolysis followed by a single stage of hydrotreating will be a more cost-effective route to hydrocarbon fuels than fast pyrolysis with multiple-stage or more-severe hydrotreating. To this end, a bench-scale bubbling fluidized bed pyrolyzer was operated at 150 g/h feed rate of pine flour with a 100 g fixed-bed catalytic upgrader. A 0.5% Pt/TiO2 catalyst produced a lower oxygen (< 20%) liquid at 40% carbon efficiency at 400 degrees C and biomass-to-catalyst ratio (B:C) of 3 for numerous cycles. The catalyst was regenerated and reused by oxidation with air and reduction with hydrogen. The oxidation and reduction times were reduced to 2 h and 1 h respectively without compromising performance or catalyst temperature control. Increasing the pyrolysis temperature from 500 degrees C to 550 degrees C allowed operation at B:C greater than 3 at comparable performance. Performance was generally similar to 2% Pt/TiO2 but at reduced catalyst cost. Projected costs are < $4/gallon of gasoline blendstock. Responses to other parameter changes and prospects for further improvements will be discussed.

09 BIOMASS FUELS↗
DOE OSTI2016

Development and Scale-Up of Copper-Based Chemical Looping with Oxygen Uncoupling

The University of Utah has been researching chemical looping with oxygen uncoupling of coal since 2007, focusing on copper-based carriers and a system configuration based on two interconnected circulating fluidized bed reactors. R&D has combined fundamental, lab-scale systems with operation of CLOU reactor systems at various scales and computational simulations for performance evaluation and reactor scale-up. Development has progressed from small lab scale through bench scale with a 10 kW dual bed research reactor to semi-pilot scale with a recently-inaugurated 220 kW chemical looping combustion process development unit. One of the challenges of scaling up copper-based CLOU technology is acquiring enough oxygen carrier material to support operation in larger reactor systems. The UofU CLC PDU, for example, requires 150-200 kg of inventory, so the oxygen carrier must be readily available in large quantities at comparatively low cost. Because no supplier capable of delivering 1+ tons of copper-based oxygen carrier material could be identified, an inexpensive oxygen carrier material was developed in-house and the carrier production process was scaled to produce large quantities of material sufficient for the CLC PDU. This presentation describes development of the CLOU process at the University of Utah, including evaluation of fundamental processes key to performance of CLOU, modeling and scale-up of the process, large-scale production of copper based oxygen carrier material and experience to date with the world’s largest dedicated CLOU reactor.

Whitty, Kevin J.↗
DOE OSTI2020

Air Pollutant Emissions and Regulatory Implications of Co-Processing Raw Bio-Oil in U.S. Petroleum Refineries

Pyrolysis oil, often referred as bio-oil or biocrude, has attracted considerable attention because it has higher energy density and carbon content compared to the raw biomass. Using pyrolysis oil derived from low cost and underutilized biomass to produce renewable hydrocarbon fuels provides a viable link between the agriculture/forestry and (petro-) chemical industry. Co-processing bio-oil with vacuum gas oil (VGO) in petroleum refinery is appealing due to the relatively low capital requirement to retrofit refinery and the compatibility of fuel products with existing infrastructure. In order to implement co-processing, a petroleum refinery would need to consider several process modifications and therefore could be subject to varying levels of air permitting requirements based on bio-oil co-processing ratio, co-processing capacity in existing units, the amount of regulated pollutants expected to be emitted, among other factors. This analysis considers co-processing 5% (by weight) of raw bio-oil with VGO in the fluidized catalytic cracking (FCC) unit(s) in a petroleum refinery. We estimate the potential increase in emissions of regulated air pollutants resulting from the modifications required to implement bio-oil co-processing and evaluate the regulatory and permitting implications for three FCC size categories in the U.S. refineries, which could co-processes raw bio-oil to produce partially renewable transportation fuels. We also assess technically feasible emission control options petroleum refineries could adopt to avoid being subject to major source permitting requirements if the estimated increase in regulated air pollutant emission exceeds the applicable threshold for major modifications. Insights from our analysis can help overcome challenges and risks associated with timely obtaining air permits required to implement bio-oil co-processing in existing refineries. Our analysis also provides needed information for decision makers (e.g., local air quality agencies) to understand the potential air quality implications for retrofitting refineries to co-process bio-oil, particularly in areas with high concentration of petroleum refineries.

09 BIOMASS FUELS↗
DOE OSTI2019

Dover Light & Power 10 MWe Coal Direct Chemical Looping Plant - Topical Report - Appendix A Environmental Information Volume

An environmental information volume was generated to support the installation of a 10 MWe coal direct chemical looping power plant at the City of Dover's municipal power plant. The coal direct chemical looping process utilizes Ohio State University's iron oxide based oxygen carrier in a moving bed reducer coupled with a circulating fluidized bed combustor.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2019

Dover Light & Power 10 MWe Coal Direct Chemical Looping Plant: Final Technical Report - Appendix A Environmental Information Volume

A 10 MWe coal direct chemical looping plant was designed for the City of Dover Municipal Power Plant. The system consisted of a moving bed reducer and circulating fluidized bed combustor. An iron-oxide oxygen carrier was used. The steam cycle included in bed surface in the combustor and conventional convection pass surface. A thorough environmental information volume was generated to support the installation of the system at the plant.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2017

Reduced Order Description of Experimental Two-Phase Pipe Flows: Characterization of Flow Structures and Dynamics via Proper Orthogonal Decomposition

Multiphase pipe flow is investigated using proper orthogonal decomposition for tomographic X-ray data, where holdup, cross-sectional phase distributions and phase interface characteristics within the pipe are obtained. Six cases of stratified and mixed flow with water content of 10%, 30% and 80% are investigated to gain insight into effects of velocity and proportion of water on the flow fields. Dispersed and slug flows are separately analyzed to consider the added interface complexity of the flow fields. These regimes are also highly applicable to industry operational flows. Instantaneous and fluctuating phase fractions of the four flow regime are analyzed and reduced order dynamical descriptions are generated. Stratified flow cases display coherent structures that highlight the liquid-liquid interface location while the mixed flow cases show minimal coherence of the eigenmodes. The dispersed flow displays coherent structures for the first few modes near the horizontal center of the pipe, representing the liquid-liquid interface location while the slug flow case shows coherent structures that correspond to the cyclical formation and break up of the slug in the first 5 modes. The low order descriptions of the high water content, stratified flow field indicates that main characteristics can be captured with minimal degrees of freedom. Reconstructions of the dispersed flow and slug flow cases indicate that dominant features are observed in the low order dynamical description utilizing less than 1%of the full order model. POD temporal coefficients a1, a2 and a3 show a high level of interdependence for the slug flowcase. The coefficients also describe the phase fraction holdup as a function of time for both dispersed and slug flow. The second coefficient, a2, and the centerline holdup profile show a mean percent difference below 9% between the two curves. The mathematical description obtained from the decomposition will deepen the understanding of multiphase flow characteristics and is applicable to long distance multiphase transport pipelines, fluidized beds, hydroelectric power and nuclear processes to name a few.

Viggiano, Bianca↗
DOE OSTI2020

Transformation enabled nitride magnets absent rare earths and a process of making the same

A process for producing an ordered martensitic iron nitride powder that is suitable for use as a permanent magnetic material is provided. The process includes fabricating an iron alloy powder having a desired composition and uniformity; nitriding the iron alloy powder by contacting the material with a nitrogen source in a fluidized bed reactor to produce a nitride iron powder; transforming the nitride iron powder to a disordered martensitic phase; annealing the disordered martensitic phase to an ordered martensitic phase; and separating the ordered martensitic phase from the iron nitride powder to yield an ordered martensitic iron nitride powder.

Matthiesen, David↗