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Results for “Gas-solid separation”

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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DOE OSTI2022

Design of a gas-solid-solid separator to remove ash from circulating fluidized bed reactors

Cyclones are one of the most common types of gas-solid separators used in circulating fluidized bed boilers. However, cyclones typically do not allow ash to leave the system through the cyclone exit, causing ash to build up in the fluidized bed and necessitating additional systems to remove ash that builds up in the bed. In this study, an alternative “disengager” gas-solid separator is proposed as a way of inherently separating small and large solids, resulting in a gas-solid-solid separation system where ash is allowed to leave the system along with gas while the desired fluidized bed material is retained. Unlike cyclones, which rely on centrifugal force to separate solids and gas, the disengager separates based on entrainment velocity of the particles. Upwards-flowing gas and particles strike a deflection plate and enter the disengaging chamber where particles with low terminal velocity such as ash fines flow with the gas, while larger particles such as sand fall to the bottom of the separator and are returned to the fluidized bed. In this study, several different proposed disengager configurations are simulated and compared to a typical cyclone using computational fluid dynamic (CFD) simulations. Furthermore, it was found that separation efficiency in the disengager is strongly influenced by the size of the deflection plate, rather than by the size of the unit itself. The predicted separation efficiency showed that compared to a cyclone, the disengager design allows significantly more ash to exit the system but retains a similar amount of desirable material. Additionally, the disengager was predicted to not suffer significantly more erosion that a cyclone.

42 ENGINEERING↗

DOE OSTI2022

Method and apparatus for desalinating water

This disclosure concerns a system and a method for removing dissolved solids from liquids. Specific implementations concern desalinating water. The system may comprise a blower, such as a thermal fan/compressor, configured to atomize a solid-bearing liquid to produce a hot, humid gas containing dissolved solids; a gas-solid separator configured to receive hot, humid gas containing entrained dissolved solids from the blower to separate the solids from the humid gas and to transmit the humid gas with solids removed through an exit port; a heater configured to heat the hot, humid gas received from the exit port of the gas-solid separator; and a condenser configured to receive heated humid gas from the heater and to condense solids-free liquid therefrom. The thermal fan/compressor may comprise a plurality of nozzles with outlets positioned adjacent atomization apertures across which a solid-bearing liquid flows and through which gas exiting the nozzles passes.

Abbasi, Bahman↗

DOE OSTI2023

Method and apparatus for desalinating water

Abbasi, Bahman↗

NASA NTRS1980

Factors affecting cleanup of exhaust gases from a pressurized, fluidized-bed coal combustor

The cleanup of effluent gases from the fluidized-bed combustion of coal is examined. Testing conditions include the type and feed rate of the coal and the sulfur sorbent, the coal-sorbent ratio, the coal-combustion air ratio, the depth of the reactor fluidizing bed, and the technique used to physically remove fly ash from the reactor effluent gases. Tests reveal that the particulate loading matter in the effluent gases is a function not only of the reactor-bed surface gas velocity, but also of the type of coal being burnt and the time the bed is operating. At least 95 percent of the fly ash particules in the effluent gas are removed by using a gas-solids separator under controlled operating conditions. Gaseous pollutants in the effluent (nitrogen and sulfur oxides) are held within the proposed Federal limits by controlling the reactor operating conditions and the type and quantity of sorbent material.

Rollbuhler, R. J.↗

NASA NTRS1981

Lewis Research Center's coal-fired, pressurized, fluidized-bed reactor test facility

A 200-kilowatt-thermal, pressurized, fluidized-bed (PFB) reactor, research test facility was designed, constructed, and operated as part of a NASA-funded project to assess and evaluate the effect of PFB hot-gas effluent on aircraft turbine engine materials that might have applications in stationary-power-plant turbogenerators. Some of the techniques and components developed for this PFB system are described. One of the more important items was the development of a two-in-one, gas-solids separator that removed 95+ percent of the solids in 1600 F to 1900 F gases. Another was a coal and sorbent feed and mixing system for injecting the fuel into the pressurized combustor. Also important were the controls and data-acquisition systems that enabled one person to operate the entire facility. The solid, liquid, and gas sub-systems all had problems that were solved over the 2-year operating time of the facility, which culminated in a 400-hour, hot-gas, turbine test.

Kobak, J. A.↗

NASA NTRS2000

Separation of Carbon Monoxide and Carbon Dioxide for Mars ISRU-Concepts

Solid oxide electrolyzers, such as electrolysis cells utilizing yttria-stabilized zirconia, can produce oxygen from Mars atmospheric carbon dioxide and reject carbon monoxide and unreacted carbon dioxide in a separate stream. The oxygen-production process has been shown to be far more efficient if the high-pressure, unreacted carbon dioxide can be separated and recycled back into the feed stream. Additionally, the mass of the adsorption compressor can be reduced. Also, the carbon monoxide by-product is a valuable fuel for space exploration and habitation, with applications from fuel cells to production of hydrocarbons and plastics. In our research, we will design, construct, and test an innovative, robust, low mass, low power separation device that can recover carbon dioxide and carbon monoxide for Mars ISRU. Such fundamental process technology, involving gas-solid phase separation in a reduced gravitational environment, will help to enable Human Exploration and Development of Space. The separation device will be scaled to operate with a CO2 sorption compressor and a zirconia electrolysis device built at the NASA Ames Research Center and the University of Arizona, respectively. In our research, we will design, construct, and test an innovative, robust, low mass, low power separation device that can recover carbon dioxide and carbon monoxide for Mars ISRU, Such fundamental process technology, involving gas-solid phase separation in a reduced gravitational environment, will help to enable Human Exploration and Development of Space. The separation device will be scaled to operate with a CO2 sorption compressor and a zirconia electrolysis device built at the NASA Ames Research Center and the University of Arizona, The separation device will be scaled to operate with a CO2 sorption compressor and a zirconia electrolysis device built at the NASA Ames Research Center and the University of Arizona, Research needs for the design shown are as follows: (1) The best adsorbent for the process must be determined. (2) Adsorption isotherms must be measured, both for pure components and mixtures. (3) Mathematical modeling must be performed to provide a solid framework for design. (4) The separation system must be constructed and tested. (5) System integration must be studied.

LeVan, M. Douglas↗

NASA NTRS2004

Separation of Carbon Monoxide and Carbon Dioxide for Mars ISRU

The atmosphere of Mars has many resources that can be processed to produce things such as oxygen, fuel, buffer gas, and water for support of human exploration missions. Successful manipulation of these resources is crucial for safe, cost-effective, and self-sufficient long-term human exploration of Mars. In our research, we are developing enabling technologies that require fundamental knowledge of adsorptive gas storage and separation processes. In particular, we are designing and constructing an innovative, low mass, low power separation device to recover carbon dioxide and carbon monoxide for Mars ISRU (in-situ resource utilization). The technology has broad implications for gas storage and separations for gas-solid systems that are ideally suited for reduced gravitational environments. This paper describes our separation process design and experimental procedures and reports results for the separation of CO2 and CO by a four-step adsorption cycle.

Walton, Krista S.↗

NASA NTRS1993

Isotopic composition and concentration of sulfur in carbonaceous chondrites

New sulfur isotopic ratio measurements are reported for seven carbonaceous chondrites. Newly developed procedures permit measurement of delta S-33, delta S-34, and delta S-36 at precisions significantly greater than previously reported. A search for S-36 nucleosynthetic anomalies coproduced with anomalies in, for example, Ti-50 and Ca-48 was negative. The high endemic sulfur concentration probably dilutes any S-36 anomaly, and separation of individual sulfur phases may be needed to identify S-36 carrier phases. Large internal isotopic variations are observed, deriving from parent body and possibly nebular processes. Chondrule separates from Allende demonstrate isotopic compositions which vary as a function of diameter. High-temperature gas-solid exchange and a two-component mixing model may account for the observations. High-resolution isotopic data and structural information are reported for organic sulfur compounds separated by chemical extractions. The insoluble organics appear to be of either aliphatic or alicyclic structure and are dominant phases.

Gao, Xia↗

DOE OSTI2022

On the adsorption and reactivity of element 114, flerovium

Flerovium (Fl, element 114) is the heaviest element chemically studied so far. To date, its interaction with gold was investigated in two gas-solid chromatography experiments, which reported two different types of interaction, however, each based on the level of a few registered atoms only. Whereas noble-gas-like properties were suggested from the first experiment, the second one pointed at a volatile-metal-like character. Here, we present further experimental data on adsorption studies of Fl on silicon oxide and gold surfaces, accounting for the inhomogeneous nature of the surface, as it was used in the experiment and analyzed as part of the reported studies. We confirm that Fl is highly volatile and the least reactive member of group 14. Our experimental observations suggest that Fl exhibits lower reactivity towards Au than the volatile metal Hg, but higher reactivity than the noble gas Rn.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗