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At least 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Reversible Methane Electrochemical Reactors as Efficient Energy Storage for Fossil Power

The overall objective of the project was to conduct a comprehensive Research & Development (R&D) program to demonstrate the suitability and future advancement and integration of reversible methane protonic ceramic electrochemical reactors (PCERs) as an efficient Energy Storage System (ESS) with fossil fuel power plants. Fundamental process and system models are developed to conduct a preliminary conceptual study and investigate the power plant system integration requirements, performance requirements, and technical and non-technical gaps for eventual implementation at system level. Technology maturation requirements is also investigated through identifying the critical technical elements and networking with industrial technology developers and end-users.

08 HYDROGEN↗
DOE OSTI2017

Electrochemical Membrane for Carbon Dioxide Capture and Power Generation

FuelCell Energy, Inc. (FCE), in collaboration with AECOM Corporation (formerly URS Corporation) and Pacific Northwest National Laboratory, has been developing a novel Combined Electric Power and Carbon-dioxide Separation (CEPACS) system. The CEPACS system is based on electrochemical membrane (ECM) technology derived from FCE’s carbonate fuel cell products featuring internal (methane steam) reforming and carrying the trade name of Direct FuelCell®. The unique chemistry of carbonate fuel cells offers an innovative approach for separation of CO 2 from existing fossil-fuel power plant exhaust streams (flue gases). The ECM-based CEPACS system has the potential to become a transformational CO 2 -separation technology by working as two devices in one: it separates the CO 2 from the exhaust of other plants such as an existing coal-fired plant and simultaneously produces clean electric power at high efficiency using a supplementary fuel. The development effort was carried out under the U.S. Department of Energy (DOE) cooperative agreement DE-FE0007634. The overall objective of this project was to successfully demonstrate the ability of FCE’s ECM-based CEPACS system technology to separate ≥90% of the CO 2 from a simulated Pulverized Coal (PC) power plant flue gas stream and to compress the captured CO2 to a state that can be easily transported for sequestration or beneficial use. In addition, a key objective was to show, through the technical and economic feasibility study and bench scale testing, that the ECM-based CEPACS system is an economical alternative for CO 2 capture in PC power plants, and that it meets DOE’s objective related to the incremental cost of electricity (COE) for post-combustion CO 2 capture (no more than 35% increase in COE). The project was performed in three budget periods (BP). The specific objective for BP1 was to complete the Preliminary Technical and Economic Feasibility Study. The T&EF study was based on the carbon capture system size suitable for a reference 550 MW PC power plant. The specific objectives for BP2 were to perform (flue gas) contaminant effect evaluation tests, small area membrane tests using clean simulated flue gas, design a flue gas pretreatment system for processing of the gas feed to ECM, update the Technical & Economic Feasibility Study (T&EFS) incorporating results of contaminant effect tests and small area membrane tests, and to prepare a test facility for bench scale testing. The specific objectives for BP3 were to perform bench scale testing (parametric and long-duration testing) of a 11.7 m 2 ECM-based CO 2 capture, purification and compression system, and update (as final) the Technical and Economic Feasibility Study. In addition, an Environmental Health and Safety evaluation (assessment) of the ECM technology was included. This final technical report presents the progress made under the project.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2017

2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy, Volume 2: Environmental Sustainability Effects of Select Scenarios from Volume 1

With the goal of understanding environmental effects of a growing bioeconomy, the U.S. Department of Energy (DOE), national laboratories, and U.S. Forest Service research laboratories, together with academic and industry collaborators, undertook a study to estimate environmental effects of potential biomass production scenarios in the United States, with an emphasis on agricultural and forest biomass. Potential effects investigated include changes in soil organic carbon (SOC), greenhouse gas (GHG) emissions, water quality and quantity, air emissions, and biodiversity. Effects of altered land-management regimes were analyzed based on select county-level biomass-production scenarios for 2017 and 2040 taken from the 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy (BT16), volume 1, which assumes that the land bases for agricultural and forestry would not change over time. The scenarios reflect constraints on biomass supply (e.g., excluded areas; implementation of management practices; and consideration of food, feed, forage, and fiber demands and exports) that intend to address sustainability concerns. Nonetheless, both beneficial and adverse environmental effects might be expected. To characterize these potential effects, this research sought to estimate where and under what modeled scenarios or conditions positive and negative environmental effects could occur nationwide. The report also includes a discussion of land-use change (LUC) (i.e., land management change) assumptions associated with the scenario transitions (but not including analysis of indirect LUC [ILUC]), analyses of climate sensitivity of feedstock productivity under a set of potential scenarios, and a qualitative environmental effects analysis of algae production under carbon dioxide (CO 2 ) co-location scenarios. Because BT16 biomass supplies are simulated independent of a defined end use, most analyses do not include benefits from displacing fossil fuels or other products, with the exception of including a few illustrative cases on potential reductions in GHG emissions and fossil energy consumption associated with using biomass supplies for fuel, power, heat, and chemicals. Most analyses in volume 2 show potential for a substantial increase in biomass production with minimal or negligible environmental effects under the biomass supply constraints assumed in BT16. Although corn ethanol has been shown to achieve GHG emissions improvements over fossil fuels, cellulosic biomass shows further improvements in certain environmental indicators covered in this report. The harvest of agricultural and forestry residues generally shows the smallest contributions to changes in certain environmental indicators investigated. The scenarios show national-level net SOC gains. When expanding the system boundary in illustrative cases that consider biomass end use, reductions in GHG emissions are estimated for scenarios in which biomass—rather than oil, coal, and natural gas—is used to produce fuel, power, heat, and chemicals. Analyses of water quality reveal that there could be tradeoffs between biomass productivity and some water quality indicators, but better outcomes for both biomass productivity and water quality can be achieved with selected conservation practices. Biodiversity analyses show possible habitat benefits to some species, with other species showing potential adverse effects that may require additional safeguards. Increasing productivity of algae can reduce GHG emissions and water consumption associated with producing algal biomass, though the effects of water consumption are likely of greater concern in some regions than in others. Moreover, the effects of climate change on potential biomass production show gains and losses in yield among feedstocks across the continental United States. Key research gaps and priorities include actions that can enhance benefits and reduce potential for negative effects of increased biomass production. The results from this report will help DOE, the bioenergy industry, and other institutions continue important discussions on environmental effects and will help chart a path toward a more environmentally sustainable bioeconomy.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Electrochemical conversion of coal-derived CO 2 into fuels and chemicals using a modified PEM electrolyzer. Final report

Opus 12 is developing an electrochemical process to convert CO 2 into chemicals and fuels. Using only CO 2 , water, and electricity as inputs, the electrochemical reduction of CO 2 could form the basis of an artificial carbon cycle that replaces a wide range of products that are currently derived from fossil fuel resources. We have developed a prototype that demonstrates high selectivity and current density for CO 2 conversion to CO, which can be used to make high-value products including methanol, acetic acid, polymers, and pharmaceuticals.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2012

An early deployment strategy for carbon capture, utilisation, and storage

This report describes the current use of CO2 for EOR, and discusses potential expansion of EOR using CO2 from power plants. Analysis of potential EOR development in the USA, where most current CO2-based EOR production takes place, indicates that relatively low cost, traditional sources of CO2 for EOR (CO2 domes and CO2 from natural gas processing plants) are insufficient to exploit the full potential of EOR. To achieve that full potential will require use of CO2 from combustion and gasification systems, such as fossil fuel power plants, where capture of CO2 is more costly. The cost of current CCUS systems, even with the revenue stream for sale of the CO2 for EOR, is too high to result in broad deployment of the technology in the near term. In the longer term, research and development may be sufficient to reduce CO2 capture costs to a point where CCUS would be broadly deployed. This report describes a case study of conditions in the USA to explore a financial incentive to promote early deployment of CCUS, providing a range of immediate benefits to society, greater likelihood of reducing the long-term cost of CCUS, and greater likelihood of broad deployment of CCUS and CCS in the long term. Additionally, it may be possible to craft such an incentive in a manner that its cost is more than offset by taxes flowing from increased domestic oil production. An example of such an incentive is included in this report.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2021

Regulators’ Energy Transition Primer: Economic Impacts of the Energy Transition on Energy Communities, Environmental Justice Considerations, and Implications on Clean Energy Jobs

Applications of new technology, such as horizontal drilling and hydraulic fracturing, enabled the United States to significantly increase its production of oil and natural gas during the last decade—the “Shale Gas Revolution.” As natural gas began to dominate the market with abundant supply and low prices, coal production and consumption have declined. Concurrently, the competitiveness of renewable energy and energy storage has climbed sharply, and analysts expect to see continued reductions in fossil fuel use in the coming decades. Many of these changes have been driven by market forces (i.e., low-cost natural gas and renewables), but current and future policy decisions aimed at tackling climate change concerns and reducing greenhouse gas emissions will also shape the future of the energy sector. This transition to low-carbon fuels has created both opportunities for clean energy technologies and challenges for communities traditionally dependent on fossil fuel-related industries. The power sector’s ongoing shift away from coal has left many coal miners and coal-fired power plant employees unemployed and often unprepared for jobs in other industries, including growing clean energy fields. This primer focuses on the declining coal industry, impacts on communities and workers, opportunities to transition workers who have lost their jobs to clean energy and other related sectors (including hydrogen-oriented jobs), recruitment and training strategies, and available programs and actions to make the shift to a low-carbon economy in a fair, just, and equitable manner by engaging the resources of federal and state governments, as well as the private sector.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2016

Pilot-Scale Demonstration of a Fully Integrated Commercial Process for Converting Woody Biomass into Clean Biomass Diesel Fuel

The economic recovery of petroleum, like other fossil fuels, is limited. Although the current price of oil has dramatically dropped due to increased production and new production methods, it is not expected to remain low for an extended period of time as demand increases. While new methods of obtaining these fossil energy reserves are constantly being invented and introduced, the cost of production generally continues to increase. New sources of energy such as fracking and oil shale or oil sands recovery can produce enormous amounts of energy, but at a severe cost. The current estimate on energy return for energy invested for oil shale for instance is just barely over 1, meaning that for every barrel of energy produced by oil shale there was nearly a barrel of energy invested to recover it. Furthermore, these new technologies are often constantly under attack for environmental concerns (especially given the poor ratio of energy conversion), while conventional oil is regarded as dangerous due to lack of domestic supply and susceptibility to foreign intervention that compromises overall national security. Alternatives to a petroleum-based supply of fuel are a potential route to address these issues, although they must also be economically feasible. The fuels industry is forced to consider these issues in addition to federal mandates intended to gradually diversify our fuel sources.

09 BIOMASS FUELS↗
DOE OSTI2018

Techno-Economic Analysis and Life-Cycle Assessment for Gas Phase Catalytic Oxidation of Lignin to Produce Phenolic Compounds

Displacing fossil fuels with biofuels is an effective way to sustainably mitigate greenhouse gas (GHG) emissions and natural resource consumption. As DOE's only national laboratory solely dedicated to researching and developing clean energy and energy efficiency technologies, NREL has been developing conceptual biomass-to-fuels conversion processes. To improve the economic feasibility of biofuels production from lignocellulosic biomass, NREL's researchers have been exploring various design options. Our team has developed a vapor phase selective oxidation process that will convert lignin streams from biofuels production into high-value chemicals and thereby improve the economics and GHG emissions of biofuels plants. This approach is directed towards valorizing lignin, which is often treated as waste or burnt for low value process heat. For techno-economic analysis (TEA) and life-cycle assessment (LCA), we have developed and modeled this hybrid process: 1) biochemically converting C5/C6 sugars from biomass to a hydrocarbon blendstock, and 2) thermochemically converting lignin from biomass, via selective partial oxidation of lignin pyrolysis vapor, to phenols. Results from the TEA and LCA for this process will be presented and discussed. The lignin valorization readily improves the biofuel production cost and reduces the life cycle carbon footprint. Even though more electricity is required as lignin is used for coproduct production instead of for heat and power generation, the GHG coproduct credit from phenols is more than enough to compensate for the GHG associated with the additional import electricity use. These analyses show that our process to produce phenol has significant economic and environmental impacts, which will enable biofuel production.

09 BIOMASS FUELS↗
DOE OSTI2014

Geothermal Power Production: Alternative Scenarios and Critical Issues

This is the last in a series of reports that completes the life cycle analyses (LCAs) of geothermal power production technologies conducted by Argonne National Laboratory. It addresses the remaining critical issues pertaining to the LCAs of geothermal electricity production: the relative contributions from plant operations and maintenance (O&M), from decommissioning (dcm), from well field exploration, and from plant operational greenhouse gas (GHG) emissions to the total life cycle performance of geothermal power plants. Contributions from O&M and dcm to the performance of other power generating technologies are also discussed. Also included in this study are LCA results for a new series of scenarios for geothermal power production. Our analysis uses fossil fuel energy consumption and GHG emissions per unit of lifetime electricity output (referred to as the fossil energy and GHG ratios, respectively) as the life cycle metrics for quantifying life cycle stage contributions to their corresponding totals, which were subsequently used for comparing the environmental performance of geothermal and other electric power production plants. Based on literature results, we concluded that the contribution from dcm to both ratios is negligible for power plants in general. Further, we found that the contribution from O&M to both ratios is generally significant for facilities with no fuel cycle (fuel production and use) burdens. In the case of geothermal power production, O&M contributes about 20% to the total for enhanced geothermal power plants, 10% for geothermal binary plants, and about 25% of the energy ratio for geothermal flash and dry steam plants. However, due to operational GHG emissions that are unique among geothermal power plants, O&M contributes only about 1% of total GHG ratios for flash and dry steam plants. These GHG emissions arise when the geofluids of these plants become exposed to the atmosphere, thus releasing dissolved GHGs. The amount of GHG emissions from these plants had a wide range. However, we found that 85% of California’s running capacity in flash and dry steam plants released 160 grams or less per kilowatt-hour of electricity produced. We developed an exploration model to account for core hole, slim hole, and confirmation well drilling that includes a probability of success for confirmation well drilling. The model shows that well field exploration represents about 20% of the total life cycle burden for large geothermal plants with numerous wells and 32% of the burden for small plants with few wells. We also analyzed a set of geothermal scenario pairs. The objective was to identify geothermal scenarios with a lower levelized cost of electricity and lower life cycle burdens. A comparison of reference with improved cases within each pair revealed that the improved cases demonstrated a lower levelized cost of electricity and lower fossil energy consumption and GHG metrics. The scenario pairs covered a range of plant capacities, well numbers and depths, resource temperatures, and plant lifetimes. Finally, we found that compared to fossil-fuel generation of electricity, both flash and dry steam geothermal electricity generation result in fewer GHG emissions: on average, only one-fifth of the GHG emissions per kilowatt-hour from a natural gas combined-cycle plant, and one-tenth of those from a coal-fired plant. Moreover, these fractions were much smaller when the fossil plants were compared with plants that use geothermal binary technology.

Sullivan, J. L.↗
DOE OSTI2017

Nuclear Fuel Cycle Simulator as a Means to Model a Nuclear Hybrid Energy System

With a growing concern for how greenhouse gas (GHG) emissions impact climate change, there is a clear value in minimizing reliance on fossil fuels. Fluctuating renewable energy sources continue to penetrate the grid at higher levels. One means of ensuring a reliable electricity supply, while maintaining low overall GHG emissions, is to couple a nuclear power plant to the fluctuating renewable electricity source. Nuclear hybrid energy systems (NHES) focus on combining renewable and nuclear generation with industrial processes to ensure reliable energy generation as well as profitability of the system as a whole. This paper analyzes the current state of NHES models, and suggests how a nuclear fuel cycle simulator (NFCS) could be used to quickly model a nuclear hybrid energy system to address long term policy concerns. NFCSs are used to model the nuclear fuel cycle, which consists of uranium mining, enrichment, the reactor, reprocessing, and long term storage of waste. The simulations can span over hundreds of years to demonstrate different approaches to managing costs, waste disposal, and proliferation concerns. Current NHES models, on the other hand, focus on shorter time periods, primarily on a daily to weekly scale, and answer questions surrounding feasibility and costs for both normal and extreme scenarios. First, this paper will discuss the different criterion that are important to modeling a NHES. Then, we will break down the characteristics of a NFCS, analyzing how the characteristics of NHES and the fuel cycle overlap. After discussing the current modeling approaches for NHES and NFCS, this paper will analyze the benefits of using a NFCS to model a NHES. This paper will conclude that a NFCS, if appropriately augmented to account for the dynamic aspects of a NHES, can produce a flexible, high level NHES model quickly.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2012

Annual Report: Fuels (30 September 2012)

The thermochemical conversion of fossil fuels through gasification will likely be the cornerstone of future energy and chemical processes due to its flexibility to accommodate numerous feeds (coal, biomass, natural gas, municipal waste, etc.) and to produce a variety of products (heat, specialty chemicals, power, etc.), as well as the inherent nature of the process to facilitate near zero emissions. Currently, the National Energy Technology Laboratory (NETL) Fuels Program has two pathways for syngas utilization: The production of transportation fuels, chemicals, or chemical intermediates. The hydrogen production as an intermediate for power production via advanced combustion turbines or fuel cells. Work under this activity focuses on the production, separation, and utilization of hydrogen from syngas using novel separation materials and processes. Advanced integrated gasification combined cycle (IGCC) schemes require the production of clean hydrogen to fuel innovative combustion turbines and fuel cells.

08 HYDROGEN↗
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 OSTI2013

Flue gas cleanup using the Moving-Bed Copper Oxide Process

The use of copper oxide on a support had been envisioned as a gas cleanup technique to remove sulfur dioxide (SO{sub 2}) and nitric oxides (NO{sub x}) from flue gas produced by the combustion of coal for electric power generation. In general, dry, regenerable flue gas cleanup techniques that use a sorbent can have various advantages, such as simultaneous removal of pollutants, production of a salable by-product, and low costs when compared to commercially available wet scrubbing technology. Due to the temperature of reaction, the placement of the process into an advanced power system could actually increase the thermal efficiency of the plant. The Moving-Bed Copper Oxide Process is capable of simultaneously removing sulfur oxides and nitric oxides within the reactor system. In this regenerable sorbent technique, the use of the copper oxide sorbent was originally in a fluidized bed, but the more recent effort developed the use of the sorbent in a moving-bed reactor design. A pilot facility or life-cycle test system was constructed so that an integrated testing of the sorbent over absorption/regeneration cycles could be conducted. A parametric study of the total process was then performed where all process steps, including absorption and regeneration, were continuously operated and experimentally evaluated. The parametric effects, including absorption temperature, sorbent and gas residence times, inlet SO{sub 2} and NO{sub x} concentration, and flyash loadings, on removal efficiencies and overall operational performance were determined. Although some of the research results have not been previously published because of previous collaborative restrictions, a summary of these past findings is presented in this communication. Additionally, the potential use of the process for criteria pollutant removal in oxy-firing of fossil fuel for carbon sequestration purposes is discussed.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2025

Assessing the Impact of Energy Transition Initiatives on the Policy Cost of Saudi Arabia's Net-Zero Ambition

Saudi Arabia's ambitious goal to achieve a net-zero economy by 2060 offers a unique opportunity to diversify away from fossil fuels while fostering long-term economic resilience and sustainability. Crucial to this transition are energy policies that guide the Kingdom from a fossil fuel-based economy toward carbon neutrality. This study uses GCAM-KSA, a multi-sectoral integrated assessment model tailored to Saudi Arabia's economic and energy systems, to evaluate the impact of early energy transition initiatives on the policy costs of achieving the Kingdom's net-zero target. These initiatives include ongoing and proposed energy efficiency measures, renewable energy deployment, and fuel displacement targets. The study highlights that early implementation of these initiatives can significantly reduce barriers to adopting low-carbon technologies, ultimately lowering the economic burden of achieving the net-zero goal. Compared to a delayed implementation scenario, early action reduces long-term policy costs by 38–72% over the period from 2025 to 2060, driven by accelerated energy system transformation. These findings provide valuable insights into how Saudi Arabia's energy policies can mitigate economic challenges, promote economic diversification, and contribute to global emission reductions, reinforcing the Kingdom's transition to a sustainable net-zero economy.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2012

Strategic Partnerships Final LDRD Report: Nanocomposite Materials for Efficient Solar Hydrogen Production

This 'campus executive' project sought to advance solar thermochemical technology for producing chemical fuels. The project advanced the common interest of Sandia National Laboratories and the University of Arizona in creating a sustainable and viable alternative to fossil fuels. The focus of this effort was in developing new methods for creating unique monolithic composite structures and characterizing their performance in thermochemical production of hydrogen from water. The development and processing of the materials was undertaken in the Materials Science and Engineering Department at the University of Arizona; Sandia National Laboratories performed the thermochemical characterization. Ferrite/yttria-stabilized zirconia composite monoliths were fabricated and shown to have exceptionally high utilization of the ferrite for splitting CO 2 to obtain CO (a process analogous to splitting H 2 O to obtain H 2 ).

08 HYDROGEN↗
DOE OSTI2021

Experimental and Kinetic Modeling Study of 3-Methyl-2-butenol (Prenol) Oxidation

Longer chain alcohols with 4–5 carbon atoms are attractive alternative fuels as they can be derived from biological sources and since their combustion leads to lower exhaust gas levels of NO x and soot compared to commercial fossil fuels. The auto-ignition behavior of fuels that contain both a hydroxyl group and a C=C double bond in their molecular structure is not well established in the literature. Understanding the influence of these functional groups on the ignition behavior of fuels is critical in the development of tailor-made fuels for advanced combustion engines. In this study, ignition delay times of an unsaturated alcohol, 3-methyl-2-butenol (prenol), are measured using a high-pressure shock tube and a rapid compression machine at pressures of 15 and 30 bar at equivalence ratios of 0.5, 1.0, and 2.0 in “air” in the temperature range 600–1400 K. Furthermore, a detailed kinetic model is developed and validated using the new experimental data in this study. In addition, speciation data in a jet-stirred reactor, ignition delay times, and laminar burning velocities available in the literature were also used to validate the new kinetic model. Fuel flux and sensitivity analyses are performed using this new model to determine the important fuel consumption pathways and critical reactions that affect the reactivity of prenol.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Toward a tunable fabrication of multifunctional iron-aluminum spinels via solution combustion synthesis: The effects of fuel, heating mode, and Fe:Al precursor ratio

The solid solutions of iron and aluminum spinels (hercynite, maghemite, magnetite, and γ-alumina) are promising materials for emerging technologies such as solar thermochemical fuel production and clean dehydrogenation of fossil fuels. Solution combustion synthesis (SCS) is an attractive technique for the fabrication of these materials as it has been used for synthesis of many nanoscale oxides. However, the design space of SCS is large with many synthesis parameters affecting the properties of the combustion products. To optimize the SCS of these materials, it is important to determine which parameters yield the best properties. In the present work, FeAlO x nanocomposites were obtained by SCS using iron nitrate and aluminum nitrate as precursors and oxidizers. Two fuels (citric acid and glycine), three Fe:Al molar ratios (1:2, 1:1, and 2:1) in the precursors, and three heating modes (hotplate, muffle furnace, and microwave oven) were compared. The products were characterized by X-ray diffraction analysis, scanning electron microscopy, Brunauer-Emmett-Teller surface area analysis, and laser diffraction particle size analysis. The fuel used had the largest impact on the combustion behavior and hence the material properties. The high combustion temperature of glycine allowed for the formation of an FeAl 2 O 4 /Fe 3 O 4 solid solution, while the lower-temperature combustion of citric acid yielded Al-substituted γ-Fe 2 O 3 with high amorphous content. With citric acid, the specific surface area as high as 200 m 2 /g was achieved. The effect of Fe:Al precursor ratio was clearly seen in variations of the lattice parameter, which demonstrated the ability to tune the phase composition. The heating mode had minor effects on material properties, but some differences were observed. As a result, all products obtained by SCS in a microwave oven had low specific surface areas compared to those obtained with a hotplate and a muffle furnace.

Alumina↗