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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Assessment of advanced coal gasification processes

A technical assessment of the following advanced coal gasification processes is presented: high throughput gasification (HTG) process; single stage high mass flux (HMF) processes; (CS/R) hydrogasification process; and the catalytic coal gasification (CCG) process. Each process is evaluated for its potential to produce synthetic natural gas from a bituminous coal. Key similarities, differences, strengths, weaknesses, and potential improvements to each process are identified. The HTG and the HMF gasifiers share similarities with respect to: short residence time (SRT), high throughput rate, slagging, and syngas as the initial raw product gas. The CS/R hydrogasifier is also SRT, but is nonslagging and produces a raw gas high in methane content. The CCG gasifier is a long residence time, catalytic, fluidbed reactor producing all of the raw product methane in the gasifier.

Mccarthy, J.↗
NASA NTRS1995

Hydrodynamic Stability of Multicomponent Droplet Gasification in Reduced Gravity

This investigation addresses the problem of hydrodynamic stability of a two-component droplet undergoing spherically-symmetrical gasification. The droplet components are assumed to have characteristic liquid species diffusion times that are large relative to characteristic droplet surface regression times. The problem is formulated as a linear stability analysis, with a goal of predicting when spherically-symmetric droplet gasification can be expected to be hydrodynamically unstable from surface-tension gradients acting along the surface of a droplet which result from perturbations. It is found that for the conditions assumed in this paper (quasisteady gas phase, no initial droplet temperature gradients, diffusion-dominated gasification), surface tension gradients do not play a role in the stability characteristics. In addition, all perturbations are predicted to decay such that droplets were hydrodynamically stable. Conditions are identified, however, that deserve more analysis as they may lead to hydrodynamic instabilities driven by capillary effects.

Aharon, I.↗
DOE OSTI2015

Method and system for controlling a gasification or partial oxidation process

A method and system for controlling a fuel gasification system includes optimizing a conversion of solid components in the fuel to gaseous fuel components, controlling the flux of solids entrained in the product gas through equipment downstream of the gasifier, and maximizing the overall efficiencies of processes utilizing gasification. A combination of models, when utilized together, can be integrated with existing plant control systems and operating procedures and employed to develop new control systems and operating procedures. Such an approach is further applicable to gasification systems that utilize both dry feed and slurry feed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Gasification of high ash, high ash fusion temperature bituminous coals

This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2017

Modeling Soot Oxidation and Gasification with Bayesian Statistics

This paper presents a statistical method for model calibration using data collected from literature. The method is used to calibrate parameters for global models of soot consumption in combustion systems. This consumption is broken into two different submodels: first for oxidation where soot particles are attacked by certain oxidizing agents; second for gasification where soot particles are attacked by H 2 O or CO 2 molecules. Rate data were collected from 19 studies in the literature and evaluated using Bayesian statistics to calibrate the model parameters. Bayesian statistics are valued in their ability to quantify uncertainty in modeling. The calibrated consumption model with quantified uncertainty is presented here along with a discussion of associated implications. The oxidation results are found to be consistent with previous studies. Significant variation is found in the CO 2 gasification rates.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2018

CaFe 2 O 4 oxygen carrier characterization during the partial oxidation of coal in the chemical looping gasification application

The calcium ferrite (CaFe 2 O 4 ) oxygen carrier characterization during chemical looping coal gasification was conducted using X-ray diffraction and Raman spectroscopic analysis. Density functional theory (DFT) analysis and experimental data were used to elucidate the mechanism for the selective oxidation of coal char. The Raman spectroscopic analyses indicated that the initial reduction of CaFe 2 O 4 were at the Fe (8) O 6 and Fe (7) O 6 octahedral sites which are related to the morphological changes at the [4 0 0] and [2 1 2] crystal planes. After the initial reduction, the Raman spectroscopic data indicated the remaining oxygen from Fe-O sites containing Ca (e.g. Fe–O–Ca) participated in the reduction reaction. Deep reduction of the CaFe 2 O 4 led to the removal of oxygen from the Fe–O–Ca bonds, indicated by the decrease in Raman intensities of the corresponding species, and the appearance of the CaO and Fe 0 . The oxygen ion diffusion controlling regime was due to the oxygen transfer occurring at the Fe octahedral sites. Furthermore, these results indicated calcium functions to control both the movement of oxygen ions through the solid and the rate of carbon oxidation in coal char leading to the selective oxidation to produce CO, the desirable product of the chemical looping gasification application.

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

Making coal relevant for small scale applications: Modular gasification for syngas/engine CHP applications in challenging environments

Small-scale coal gasification technology, coupled to a reciprocating engine generator, has the potential for making coal a cost competitive resource for meeting the flexible energy needs and resiliency requirements of utilities across the United States. To maintain grid stability and reliability, electrical generation must be regulated to match the load at the proper voltage and frequency. With the expansion of intermittent sources into the grid, such as wind and solar, frequency and voltage regulation become increasingly important and challenging. This work presents the results of a Front End Engineering Design (FEED) effort to detail the engineering and preliminary economics of a small-scale, air blown, fixed-bed gasification process, operating at near-atmospheric pressure, with gas cleanup to provide syngas and pyrolysis liquid fuels for use in reciprocating engine generators for combined heat and power at the University of Alaska Fairbanks. A very detailed assessment of capital and operating costs allows the evaluation of a levelized cost of electricity of 208.06 $/MWh, which can be reduced through the selling of by-products (steam for heating purposes and pyrolysis liquids to be used for power generation in an existing diesel engine). Here, a combined sensitivity analysis, based on the Monte Carlo approach, has been carried out to evaluate the effects of the uncertainties (capital and operating costs and plant annual availability) on the LCOE.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2020

A deep insight on the coal ash-to-slag transformation behavior during the entrained flow gasification process

Recent research provided deep insight on the coal ash-to-slag transformation characterization during the entrained flow gasification process, with experimentation on a 40 kg/hr (dry basis) coal-fed opposed multi-burner (OMB) entrained flow gasifier and simulation via FactSage™ software. A general mechanism is presented to relate the gasifier design temperature, ash fluid temperature, and operating temperature with the degree of the slag polymerization. The change of the high temperature zone, the corresponding particle residence time in the high temperature zone, and syngas composition have obvious effects on the slag mineral transformation behavior. Mineral types formed on the wall of the gasifier chamber were mainly anorthite (CaAl 2 Si 2 O 8 ), aluminum oxide (Al 2 O 3 ), and calcium sulfide (CaS). These minerals transformed to anorthite and diopside (CaMgSi 2 O 6 ) at the slag hole zone, while the minerals at the lock hopper were anorthite, orthoclase (KAlSi 3 O 8 ), quartz (SiO 2 ), gypsum (CaSO 4 ), calcite (CaCO 3 ), and halite (NaCl). FactSage™ predicted minerals as anorthite, diopside, orthoclase, and albite (NaAlSi 3 O 8 ), etc., where the slag temperature was below the ash fluid temperature and when the ratios of CO/CO 2 and (CO + H 2 )/CO 2 were lower than 1.0 and 2.0, respectively. By simulation, residual carbon was found to be the dominant factor over syngas composition to cause mineral transformation, and this was verified experimentally. The Ca-based crystals, typically anorthite, was shifted to diopside, near the slag hole zone, and a linear relationship was found between the content ratios of diopside/(anorthite + diopside), CaO/SiO 2 , and (CaO + MgO)/SiO 2 . A dimensionless number, θ, was defined to characterize the changing chemical composition and the degree of slag polymerization, with temperature deviation from the design condition. Three zones of θ were identified and related to the deviation between the actual gasification condition from the design condition. Finally, a low slag polymerization degree corresponded with a higher temperature deviation between the actual condition and design condition, and this proved that increased residual carbon content and changing iron valence state increased the mineral types when the slag temperature was below the ash fluid temperature.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2017

High performance noble-metal-free NiCo/AC bimetal for gasification in supercritical water

We report high performance Noble-metal-free NiCo/AC bimetal for gasification in supercritical water by the polyol reduction method with chloroplatinic acid as nucleation seed. At 475 _C and 20 min, the carbon efficiency (CE) for gasification of phenol with NiCo/AC has reached about 65%, which represents a more than 20-fold enhancement of carbon efficiency compared to the Co/AC and 6-fold compared to the Ni/AC. The CE of commercial noble Ru/C (5 wt%) catalyst is only about 15% higher than that of NiCo/AC catalyst. The catalyst was characterized by BET, XRD, XPS and TEM. The results indicate smaller and higher disperse of NiCo alloy has been achieved. By using NiCo/AC catalyst, the CE can reach about 90% at 525 _C and 60 min with a 5 wt% phenol, 0.098 kg/m3 density and catalyst loading of 0.5 g/g (the mass of NiCo/AC catalyst/the mass of phenol). The results of GCeMS indicate NiCo/AC can suppress tar successfully. A kinetic modeling was also proposed to describe gaseous product and tar formation, which gives the activation energy (Ea) 123.56 ± 31 kJ/mol and the frequency factor 16.93 ± 0.48 for gaseous products. While for tar formation, the Ea is 112.95 ± 24 kJ/mol and the frequency factor is 13.99 ± 0.37. The successful use of noble-metal-free NiCo/AC shows the potential to replace noble Ru-catalysts in SCWG process for gases fuels by bimetal.

phenol, gasification, supercritical water, NiCo/AC↗
DOE OSTI2020

Distributed power generation via gasification of biomass and municipal solid waste: A review

The access to electricity has increased worldwide, growing from 60 million additional consumers per year in 2000-2012 to 100 million per year in 2012-2016. Despite this growth, approximately 675 million people will still lack access to electricity in 2030, indicating that electricity demand will continue to increase. Unfortunately, traditional large fossil power technologies based on coal, oil and natural gas lead to a major concern in tackling worldwide carbon dioxide emissions, and nuclear power remains unpopular due to public safety concerns. Distributed power generation utilizing CO 2 -neutral sources, such as gasification of biomass and municipal solid wastes (MSW), can play an important role in meeting the world energy demand in a sustainable way. Furthermore, this review focuses on the recent technology developments on seven power generation technologies (i.e. internal combustion engine, gas turbine, micro gas turbine, steam turbine, Stirling engine, organic rankine cycle generator, and fuel cell) suitable for distributed power applications with capability of independent operation using syngas derived from gasification of biomass and MSW. Technology selection guidelines is discussed based on criteria, including hardware modification required, size inflexibility, sensitivity to syngas contaminants, operational uncertainty, efficiency, lifetime, fast ramp up/down capability, controls and capital cost. Major challenges facing further development and commercialization of these power generation technologies are discussed.

09 BIOMASS FUELS↗
DOE OSTI2015

Integrated gasification and plasma cleaning for waste treatment: A life cycle perspective

Highlights: • A life cycle assessment of an advanced two-stage process is undertaken. • A comparison of the impacts of the process when fed with 7 feedstock is presented. • Sensitivity analysis on the system is performed. • The treatment of RDF shows the lowest impact in terms of both GWP and AP. • The plasma shows a small contribution to the overall impact of the plant. - Abstract: In the past, almost all residual municipal waste in the UK was landfilled without treatment. Recent European waste management directives have promoted the uptake of more sustainable treatment technologies, especially for biodegradable waste. Local authorities have started considering other options for dealing with residual waste. In this study, a life cycle assessment of a future 20 MWe plant using an advanced two-stage gasification and plasma technology is undertaken. This plant can thermally treat waste feedstocks with different composition and heating value to produce electricity, steam and a vitrified product. The objective of the study is to analyse the environmental impacts of the process when fed with seven different feedstocks (including municipal solid waste, solid refuse fuel, reuse-derived fuel, wood biomass and commercial & industrial waste) and identify the process steps which contribute more to the environmental burden. A scenario analysis on key processes, such as oxygen production technology, metal recovery and the appropriate choice for the secondary market aggregate material, is performed. The influence of accounting for the biogenic carbon content in the waste from the calculations of the global warming potential is also shown. Results show that the treatment of the refuse-derived fuel has the lowest impact in terms of both global warming potential and acidification potential because of its high heating value. For all the other impact categories analysed, the two-stage gasification and plasma process shows a negative impact for all the waste streams considered, mainly due to the avoided burdens associated with the production of electricity from the plant. The plasma convertor, key characteristic of the thermal process investigated, although utilising electricity shows a relatively small contribution to the overall environmental impact of the plant. The results do not significantly vary in the scenario analysis. Accounting for biogenic carbon enhanced the performance of biomass and refuse-derived fuel in terms of global warming potential. The main analysis of this study has been performed from a waste management perspective, using 1 ton of waste as functional unit. A comparison of the results when 1 kWhe of electricity produced is used as functional unit shows similar trends for the environmental impact categories considered.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Bed Agglomeration During the Steam Gasification of a High Lignin Corn Stover Simultaneous Saccharification and Fermentation (SSF) Digester Residue

This research investigates the bed agglomeration phenomena during the steam gasification of a high lignin residue produced from the simultaneous saccharification and fermentation (SSF) of corn stover in a bubbling fluidized bed. The studies were conducted at 895°C using alumina as bed material. Biomass was fed at 1.5 kg/hr, while steam was fed to give a velocity equal to 2.5 times the minimum fluidization velocity, with a steam/carbon ratio of 0.9. The pelletized feedstock was co-fed with a cooling nitrogen stream to mitigate feed line plugging issues. Tar production was high at 50.3 g/Nm3, and the fraction of C10+ compounds was greater than that seen in the gasification of traditional lignocellulosic feedstocks. Carbon closures over 94 % were achieved for all experiments. Bed agglomeration was found to be problematic, indicated by pressure drop increases observed below the bed and upstream of the feed line. Two size categories of solids were recovered from the reactor, +60 mesh and -60 mesh. After a 2.75-hour experiment, 61.7 wt % was recovered as -60 mesh particles and 38.2 wt% of the recovered reactor solids were +60 mesh. A sizeable percentage, 31.8 wt%, was +20 mesh. The -60 mesh particles were mainly formed by the initial bed material (Al2O3). Almost 50 wt. % of the + 20 mesh particles was found to be formed by organics. The unreacted carbon remaining in the reactor resulted in a low conversion rate to product gas. ICP-AES, SEM, SEM-EDS, and XRD confirmed that the large agglomerates (+ 20 mesh) were not encapsulated bed material but rather un-gasified feedstock pellets with sand particles attached to it.

bioenergy↗
DOE OSTI2016

Performance analysis of a bio-gasification based combined cycle power plant employing indirectly heated humid air turbine

Rapid depletion of fossil fuel has forced mankind to look into alternative fuel resources. In this context, biomass based power generation employing gas turbine appears to be a popular choice. Bio-gasification based combined cycle provides a feasible solution as far as grid-independent power generation is concerned for rural electrification projects. Indirectly heated gas turbine cycles are promising alternatives as they avoid downstream gas cleaning systems. Advanced thermodynamic cycles have become an interesting area of study to improve plant efficiency. Water injected system is one of the most attractive options in this field of applications. This paper presents a theoretical model of a biomass gasification based combined cycle that employs an indirectly heated humid air turbine (HAT) in the topping cycle. Maximum overall electrical efficiency is found to be around 41%. Gas turbine specific air consumption by mass is minimum when pressure ratio is 6. The study reveals that, incorporation of the humidification process helps to improve the overall performance of the plant.

09 BIOMASS FUELS↗
DOE OSTI2023

NEWTS EPA Gasification Dataset and Case Studies

Data from the US EPA Gasification Database containing gasification effluent data from selected U.S. coal power plants. Original data from: Nguyen, Dan-Tam, Eastern Research Group. Sep 29, 2015. Analytical Database for the Steam Electric Rulemaking - DCN SE05359. https://www.regulations.gov/document/EPA-HQ-OW-2009-0819-5640 Files include: Original data tab, processed data and charge balance information in "NEWTS_EPA_Gasification_Effluent_Dataset_all_tabs.xlsx" Individual .csv files for data in format for input into aqueous chemistry modeling software (OLI Systems and Geochemist's Workbench) Data input templates for modeling streams in OLI Systems and Geochemist's Workbench Case studies for selected solved streams modeled in OLI Systems and Geochemist's Workbench

gasification↗
DOE OSTI2019

Innovative Gasification to Produce Fischer-Tropsch Jet and Diesel Fuel

The primary objective of this project and the U.S. DOE’s integrated biorefinery (“IBR”) program was to demonstrate conversion of biomass and waste-derived feedstocks into military spec liquid fuels. Frontline’s proposed integrated process was to incorporate several novel technologies and innovative applications of existing technologies that would serve both to increase plant efficiency and also to lower the cost of the produced biofuels. The project was intended to demonstrate Frontline Bioenergy’s technologies for gasification and synthesis gas clean-up configuration to produce a syngas stream suitable for a proven Fischer-Tropsch (“F-T”) unit that would produce F-T intermediate products. These F-T intermediate products were to be upgraded to military spec diesel and jet fuel, including F76, JP5, and JP8. Specifically, these technologies consisted of: 1. Frontline’s PMFreeGas® ultra low particulate matter (PM) hot gas filtration technology 2. Application of Frontline’s TarFreeGas® ultra low-tar gasification technology 3. Frontline’s novel approach to syngas conditioning The proposed gasifier system was to operate at 10 tpd capacity while the F-T plant was capable of approximately one barrel per day. Although the gasifier output would have been roughly ten times the F-T plant’s required input, the 10 tpd capacity was chosen to enable scaling to commercial capacity. Project partners included i) SGC Energia, owner of the F-T technology and owner of the proposed demonstration site in Pasadena, Texas; ii) Stanley Consultants, a reputable engineering company that provided detailed electrical engineering services; and iii) Delphi Engineering & Construction LLC, a consulting company that provided project management advisory services. The integrated plant was never constructed due to lack of cost share funds. However, the commercialization plan and associated financial model suggested such a plant could be economically viable when the price of oil exceeds $70 per barrel. The price of feedstock plays a significant role in the profitability of the plant for a given value of oil. An integrated biorefinery capable of producing liquid transportation fuels and other chemical feedstocks would benefit the public by providing a sustainable pathway to convert domestically available feedstocks into fuels that might otherwise be imported from countries or regions of the world that are typically hostile to the United States.

09 BIOMASS FUELS↗
DOE OSTI2017

Performance and Cost Assessment of a Coal Gasification Power Plant Integrated with a Direct-Fired sCO 2 Brayton Cycle

The objective of this study is to develop a cost and performance baseline for a coal syngas-fueled, direct-fired supercritical carbon dioxide (sCO2) power plant using coal gasification, and to analyze the sensitivity of its cost and performance to variations in operating parameter and cost assumptions. The study results yield a sCO2 baseline plant efficiency of 37.7% (HHV), with 97.6% carbon capture at 99.8% purity, much higher than the reference integrated gasification combined cycle (IGCC) plant using the same Shell gasifier (31.2% efficiency, 90% carbon capture). The economic analysis estimates a cost of electricity (COE) of $137/MWh for the mature, commercial-scale sCO2 plant (without CO2 transport and storage costs), yielding a 10% reduction in COE from the reference IGCC case. These results demonstrate the significant potential of direct sCO2 power cycles for achieving DOE’s transformational power generation goals for coal-fueled power plants with carbon capture and storage.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2025

Microwave-Assisted Catalytic Gasification of Various Biomass with Mixed Plastic Wastes for H2-Rich Syngas Production

Co-gasification of plastics mixture with biomass has shown synergistic effects in Microwave (MW) reactor resulting in higher H2-rich syngas yield and reduced char/tar. This study investigates a microwave-assisted catalytic gasification of variable feedstock such as various biomass blended with mixed plastics waste using Fe-based catalyst to produce H2 rich syngas as a primary product.

catalysis, biomass gasification↗