Science.gov

Sample records for hot gas outflow

  1. Long way to go: how outflows from large galaxies propagate through the hot halo gas

    NASA Astrophysics Data System (ADS)

    Sarkar, Kartick Chandra; Nath, Biman B.; Sharma, Prateek; Shchekinov, Yuri

    2015-03-01

    Using hydrodynamic simulations, we study the mass-loss due to supernova-driven outflows from Milky Way type disc galaxies, paying particular attention to the effect of the extended hot halo gas. We find that the total mass-loss at inner radii scales roughly linearly with total mass of stars formed, and that the mass loading factor at the virial radius can be several times its value at inner radii because of the swept up hot halo gas. The temperature distribution of the outflowing material in the inner region (˜10 kpc) is bimodal in nature, peaking at 105 K and 106.5 K, responsible for optical and X-ray emission, respectively. The contribution of cold/warm gas with temperature ≤105.5 K to the outflow rate within 10 kpc is ≈0.3-0.5. The warm mass loading factor, η3e5 (T ≤ 3 × 105 K) is related to the mass loading factor at the virial radius (ηv) as ηv ≈ 25 η3e5 (SFR/M⊙ yr-1)-0.15 for a baryon fraction of 0.1 and a starburst period of 50 Myr. We also discuss the effect of multiple bursts that are separated by both short and long periods. The outflow speed at the virial radius is close to the sound speed in the hot halo, ≲ 200 km s-1. We identify two `sequences' of outflowing cold gas at small scales: a fast (≈500 km s-1) sequence, driven by the unshocked free-wind; and a slow sequence (≈± 100 km s-1) at the conical interface of the superwind and the hot halo.

  2. Hot gas outflow in the blue compact dwarf galaxy VII Zw 403

    NASA Technical Reports Server (NTRS)

    Papaderos, P.; Fricke, K. J.; Thuan, T. X.; Loose, H.-H.

    1994-01-01

    We have observed the Blue Compact Dwarf Galaxy VII Zw 403 with the Position Sensitive Proportional Counter (PSPC) camera onboard ROSAT. We found a total X-ray luminosity of 1.94 x 10(exp 38) erg/s distributed in a central core to which are connected three elongated structures. We interpret this X-ray morphology as the result of a hot gas outflow from the core of the dwarf galaxy powered by the present starburst.

  3. Hot outflows in galaxy clusters

    NASA Astrophysics Data System (ADS)

    Kirkpatrick, C. C.; McNamara, B. R.

    2015-10-01

    The gas-phase metallicity distribution has been analysed for the hot atmospheres of 29 galaxy clusters using Chandra X-ray Observatory observations. All host brightest cluster galaxies (BCGs) with X-ray cavity systems produced by radio AGN. We find high elemental abundances projected preferentially along the cavities of 16 clusters. The metal-rich plasma was apparently lifted out of the BCGs with the rising X-ray cavities (bubbles) to altitudes between twenty and several hundred kiloparsecs. A relationship between the maximum projected altitude of the uplifted gas (the `iron radius') and jet power is found with the form R_Fe ∝ P_jet^{0.45}. The estimated outflow rates are typically tens of solar masses per year but exceed 100 M⊙ yr- 1 in the most powerful AGN. The outflow rates are 10-20 per cent of the cooling rates, and thus alone are unable to offset a cooling inflow. Nevertheless, hot outflows effectively redistribute the cooling gas and may play a significant role at regulating star formation and AGN activity in BCGs and presumably in giant elliptical galaxies. The metallicity distribution overall can be complex, perhaps due to metal-rich gas returning in circulation flows or being blown around in the hot atmospheres. Roughly 15 per cent of the work done by the cavities is expended lifting the metal-enriched gas, implying their nuclear black holes have increased in mass by at least ˜107-109 M⊙. Finally, we show that hot outflows can account for the broad, gas-phase metallicity distribution compared to the stellar light profiles of BCGs, and we consider a possible connection between hot outflows and cold molecular gas flows discovered in recent Atacama Large Millimeter Array observations.

  4. Outflow of hot and cold molecular gas from the obscured secondary nucleus of NGC 3256: closing in on feedback physics

    NASA Astrophysics Data System (ADS)

    Emonts, B. H. C.; Piqueras-López, J.; Colina, L.; Arribas, S.; Villar-Martín, M.; Pereira-Santaella, M.; Garcia-Burillo, S.; Alonso-Herrero, A.

    2014-12-01

    The nuclei of merging galaxies are often deeply buried in dense layers of gas and dust. In these regions, gas outflows driven by starburst and active galactic nuclear activity are believed to play a crucial role in the evolution of these galaxies. However, to fully understand this process it is essential to resolve the morphology and kinematics of such outflows. Using near-infrared integral-field spectroscopy obtained with SINFONI on the Very Large Telescope, we detect a kpc-scale structure of high-velocity molecular hydrogen (H2) gas associated with the deeply buried secondary nucleus of the infrared-luminous merger-galaxy NGC 3256. We show that this structure is most likely the hot component of a molecular outflow, which was recently also detected in the cold molecular gas through CO emission. This outflow, with a total molecular gas mass of MH2 ~ 2 × 107M⊙, is among the first to be spatially resolved in both the hot molecular H2 gas with VLT/SINFONI and the cold molecular CO emitting gas with ALMA. The hot and cold components share a similar morphology and kinematics, with a hot-to-cold molecular gas mass ratio of ~ 6 × 10-5. The high (~100 pc) resolution at which we map the geometry and velocity structure of the hot outflow reveals a biconical morphology with opening angle ~40° and gas spread across a FWZI ~ 1200 km s-1. Because this collimated outflow is oriented close to the plane of the sky, the molecular gas may reach maximum intrinsic outflow velocities of ~1800 km s-1, with an average mass outflow rate of at least Ṁoutfl ~ 20 M⊙ yr-1. By modeling the line-ratios of various near-infrared H2 transitions, we show that the H2-emitting gas in the outflow is heated through shocks or X-rays to a temperature of T ~ 1900 ± 300 K. The energy needed to drive the collimated outflow is most likely provided by a hidden Compton-thick AGN or by the nuclear starburst. We show that the global kinematics of the molecular outflow that we detect in NGC 3256 mimic

  5. Constraining the Dynamical Importance of Hot Gas and Radiation Pressure in Quasar Outflows Using Emission Line Ratios

    NASA Astrophysics Data System (ADS)

    Stern, Jonathan; Faucher-Giguère, Claude-André; Zakamska, Nadia L.; Hennawi, Joseph F.

    2016-03-01

    Quasar feedback models often predict an expanding hot gas bubble that drives a galaxy-scale outflow. In many circumstances this hot gas radiates inefficiently and is therefore difficult to observe directly. We present an indirect method to detect the presence of a hot bubble using hydrostatic photoionization calculations of the cold (∼ {10}4 {{K}}) line-emitting gas. We compare our calculations with observations of the broad line region, the inner face of the torus, the narrow line region (NLR), and the extended NLR, and thus constrain the hot gas pressure at distances 0.1 {{pc}}{--}10 {{kpc}} from the center. We find that emission line ratios observed in the average quasar spectrum are consistent with radiation-pressure-dominated models on all scales. On scales \\lt 40 {{pc}} a dynamically significant hot gas pressure is ruled out, while on larger scales the hot gas pressure cannot exceed six times the local radiation pressure. In individual quasars, ≈25% of quasars exhibit NLR ratios that are inconsistent with radiation-pressure-dominated models, although in these objects the hot gas pressure is also unlikely to exceed the radiation pressure by an order of magnitude or more. The derived upper limits on the hot gas pressure imply that the instantaneous gas pressure force acting on galaxy-scale outflows falls short of the time-averaged force needed to explain the large momentum fluxes \\dot{p}\\gg {L}{{AGN}}/c inferred for galaxy-scale outflows. This apparent discrepancy can be reconciled if optical quasars previously experienced a buried, fully obscured phase during which the hot gas bubble was more effectively confined and during which galactic wind acceleration occurred.

  6. Galaxy Mergers with Adaptive Mesh Refinement: Star Formation and Hot Gas Outflow

    SciTech Connect

    Kim, Ji-hoon; Wise, John H.; Abel, Tom; /KIPAC, Menlo Park /Stanford U., Phys. Dept.

    2011-06-22

    In hierarchical structure formation, merging of galaxies is frequent and known to dramatically affect their properties. To comprehend these interactions high-resolution simulations are indispensable because of the nonlinear coupling between pc and Mpc scales. To this end, we present the first adaptive mesh refinement (AMR) simulation of two merging, low mass, initially gas-rich galaxies (1.8 x 10{sup 10} M{sub {circle_dot}} each), including star formation and feedback. With galaxies resolved by {approx} 2 x 10{sup 7} total computational elements, we achieve unprecedented resolution of the multiphase interstellar medium, finding a widespread starburst in the merging galaxies via shock-induced star formation. The high dynamic range of AMR also allows us to follow the interplay between the galaxies and their embedding medium depicting how galactic outflows and a hot metal-rich halo form. These results demonstrate that AMR provides a powerful tool in understanding interacting galaxies.

  7. Evidence for a Large Scale Outflow of Hot Gas from the Scutum-Centaurus Spiral Arm

    NASA Astrophysics Data System (ADS)

    Benjamin, Robert A.

    2016-01-01

    The Scutum-Centaurus Spiral Arm, sometimes referred to as the "Molecular Ring", is one of the most prominent star-forming structures in the Milky Way Galaxy. The arm extends from a Galactic longitude of L=+30 degrees to L=-50 (310) degrees, and then behind Galactic center to become the Outer Scutum-Centaurus Arm. It is characterized by long, filamentary dark clouds, concentrated star formation, and numerous supernova remnants and bubbles. Previous models have shown that the energy input of supernova explosions can drive a "hybrid" thermal pressure/cosmic-ray pressure wind out of the Galaxy from this region and that such a wind can explain both the 3/4 keV X-ray emission observed by ROSAT as well as the high-latitude 408 MHz radio synchrotron emisison. Here the effects of Galactic rotation on this wind are demonstrated. The morphology of the X-ray and synchrotron emission as well as the behavior of the Ophiuchus superbubble (which is part of this flow) are shown to be consistent with a launching, rotating wind. Predictions for the velocity structure of this gas are provided that can be tested with future emission and absorption line studies. The importance of understanding this wind as a foreground in studies of the "Fermi Bubble" is also discussed.

  8. OUTFLOW AND HOT DUST EMISSION IN HIGH-REDSHIFT QUASARS

    SciTech Connect

    Wang, Huiyuan; Xing, Feijun; Wang, Tinggui; Zhou, Hongyan; Zhang, Kai; Zhang, Shaohua

    2013-10-10

    Correlations of hot dust emission with outflow properties are investigated, based on a large z ∼ 2 non-broad absorption line quasar sample built from the Wide-field Infrared Survey and the Sloan Digital Sky Survey data releases. We use the near-infrared slope and the infrared to UV luminosity ratio to indicate the hot dust emission relative to the emission from the accretion disk. In our luminous quasars, these hot dust emission indicators are almost independent of the fundamental parameters, such as luminosity, Eddington ratio and black hole mass, but moderately dependent on the blueshift and asymmetry index (BAI) and FWHM of C IV lines. Interestingly, the latter two correlations dramatically strengthen with increasing Eddington ratio. We suggest that, in high Eddington ratio quasars, C IV regions are dominated by outflows so the BAI and FWHM (C IV) can reliably reflect the general properties and velocity of outflows, respectively. In low Eddington ratio quasars, on the other hand, C IV lines are primarily emitted by virialized gas so the BAI and FWHM (C IV) become less sensitive to outflows. Therefore, the correlations for the highest Eddington ratio quasars are more likely to represent the true dependence of hot dust emission on outflows and the correlations for the entire sample are significantly diluted by the low Eddington ratio quasars. Our results show that an outflow with a large BAI or velocity can double the hot dust emission on average. We suggest that outflows either contain hot dust in themselves or interact with the dusty interstellar medium or torus.

  9. Detection of hot, metal-enriched outflowing gas around z ≈ 2.3 star-forming galaxies in the Keck Baryonic Structure Survey

    NASA Astrophysics Data System (ADS)

    Turner, Monica L.; Schaye, Joop; Steidel, Charles C.; Rudie, Gwen C.; Strom, Allison L.

    2015-06-01

    We use quasar absorption lines to study the physical conditions in the circumgalactic medium of redshift z ≈ 2.3 star-forming galaxies taken from the Keck Baryonic Structure Survey. In Turner et al. we used the pixel optical depth technique to show that absorption by H I and the metal ions O VI, N V, C IV, C III, and Si IV is strongly enhanced within |Δv| ≲ 170 km s-1 and projected distances |d| ≲ 180 proper kpc from sightlines to the background quasars. Here we demonstrate that the O VI absorption is also strongly enhanced at fixed H I, C IV, and Si IV optical depths, and that this enhancement extends out to ˜350 km s-1. At fixed H I the increase in the median O VI optical depth near galaxies is 0.3-0.7 dex and is detected at 2-3σ confidence for all seven H I bins that have log _{10}τ_{H I} ≥ -1.5. We use ionization models to show that the observed strength of O VI as a function of H I is consistent with enriched, photoionized gas for pixels with τ_{H I} ≳ 10. However, for pixels with τ_{H I} ≲ 1 this would lead to implausibly high metallicities at low densities if the gas were photoionized by the background radiation. This indicates that the galaxies are surrounded by gas that is sufficiently hot to be collisionally ionized (T > 105 K) and that a substantial fraction of the hot gas has a metallicity ≳10-1 of solar. Given the high metallicity and large velocity extent (out to ˜1.5 vcirc) of this gas, we conclude that we have detected hot, metal-enriched outflows arising from star-forming galaxies.

  10. HOT ELECTROMAGNETIC OUTFLOWS. I. ACCELERATION AND SPECTRA

    SciTech Connect

    Russo, Matthew; Thompson, Christopher

    2013-04-20

    The theory of cold, relativistic, magnetohydrodynamic outflows is generalized by the inclusion of an intense radiation source. In some contexts, such as the breakout of a gamma-ray burst (GRB) jet from a star, the outflow is heated to a high temperature at a large optical depth. Eventually it becomes transparent and is pushed to a higher Lorentz factor by a combination of the Lorentz force and radiation pressure. We obtain its profile, both inside and outside the fast magnetosonic critical point, when the poloidal magnetic field is radial and monopolar. Most of the energy flux is carried by the radiation field and the toroidal magnetic field that is wound up close to the rapidly rotating engine. Although the entrained matter carries little energy, it couples the radiation field to the magnetic field. Then the fast critical point is pulled inward from infinity and, above a critical radiation intensity, the outflow is accelerated mainly by radiation pressure. We identify a distinct observational signature of this hybrid outflow: a hardening of the radiation spectrum above the peak of the seed photon distribution, driven by bulk Compton scattering. The non-thermal spectrum-obtained by a Monte Carlo method-is most extended when the Lorentz force dominates the acceleration, and the seed photon beam is wider than the Lorentz cone of the MHD fluid. This effect is a generic feature of hot, magnetized outflows interacting with slower relativistic material. It may explain why some GRB spectra appear to peak at photon energies above the original Amati et al. scaling. A companion paper addresses the case of jet breakout, where diverging magnetic flux surfaces yield strong MHD acceleration over a wider range of Lorentz factor.

  11. Hot Electromagnetic Outflows. I. Acceleration and Spectra

    NASA Astrophysics Data System (ADS)

    Russo, Matthew; Thompson, Christopher

    2013-04-01

    The theory of cold, relativistic, magnetohydrodynamic outflows is generalized by the inclusion of an intense radiation source. In some contexts, such as the breakout of a gamma-ray burst (GRB) jet from a star, the outflow is heated to a high temperature at a large optical depth. Eventually it becomes transparent and is pushed to a higher Lorentz factor by a combination of the Lorentz force and radiation pressure. We obtain its profile, both inside and outside the fast magnetosonic critical point, when the poloidal magnetic field is radial and monopolar. Most of the energy flux is carried by the radiation field and the toroidal magnetic field that is wound up close to the rapidly rotating engine. Although the entrained matter carries little energy, it couples the radiation field to the magnetic field. Then the fast critical point is pulled inward from infinity and, above a critical radiation intensity, the outflow is accelerated mainly by radiation pressure. We identify a distinct observational signature of this hybrid outflow: a hardening of the radiation spectrum above the peak of the seed photon distribution, driven by bulk Compton scattering. The non-thermal spectrum—obtained by a Monte Carlo method—is most extended when the Lorentz force dominates the acceleration, and the seed photon beam is wider than the Lorentz cone of the MHD fluid. This effect is a generic feature of hot, magnetized outflows interacting with slower relativistic material. It may explain why some GRB spectra appear to peak at photon energies above the original Amati et al. scaling. A companion paper addresses the case of jet breakout, where diverging magnetic flux surfaces yield strong MHD acceleration over a wider range of Lorentz factor.

  12. Hot Gas Halos in Galaxies

    SciTech Connect

    Mulchaey, John S.; Jeltema, Tesla E.

    2010-06-08

    We use Chandra and XMM-Newton to study how the hot gas content in early-type galaxies varies with environment. We find that the L{sub X}-L{sub K} relationship is steeper for field galaxies than for comparable galaxies in groups and clusters. This suggests that internal processes such as supernovae driven winds or AGN feedback may expel hot gas from low mass field galaxies. Such mechanisms are less effective in groups and clusters where the presence of an intragroup or intracluster medium may confine outflowing material.

  13. Tracing inflows and outflows with absorption lines in circumgalactic gas

    NASA Astrophysics Data System (ADS)

    Ford, Amanda Brady; Davé, Romeel; Oppenheimer, Benjamin D.; Katz, Neal; Kollmeier, Juna A.; Thompson, Robert; Weinberg, David H.

    2014-10-01

    We examine how H I and metal absorption lines within low-redshift galaxy haloes trace the dynamical state of circumgalactic gas, using cosmological hydrodynamic simulations that include a well-vetted heuristic model for galactic outflows. We categorize inflowing, outflowing, and ambient gas based on its history and fate as tracked in our simulation. Following our earlier work, showing that the ionization level of absorbers was a primary factor in determining the physical conditions of absorbing gas, we show here that it is also a governing factor for its dynamical state. Low-ionization metal absorbers (e.g. Mg II) tend to arise in gas that will fall on to galaxies within several Gyr, while high-ionization metal absorbers (e.g. O VI) generally trace material that was deposited by outflows many Gyr ago. Inflowing gas is dominated by enriched material that was previously ejected in an outflow; hence, accretion at low redshifts is typically substantially enriched. Recycling wind material is preferentially found closer to galaxies, and is more dominant in lower mass haloes since high-mass haloes have more hot gas that is able to support itself against infall. Low-mass haloes also tend to re-eject more of their accreted material, owing to our outflow prescription that employs higher mass loading factors for lower mass galaxies. Typical H I absorbers trace unenriched ambient material that is not participating in the baryon cycle, but stronger H I absorbers arise in cool, enriched inflowing gas. Instantaneous radial velocity measures of absorbers are generally poor at distinguishing between inflowing and outflowing gas, except in the case of very recent outflows. These results suggest that probing halo gas using a range of absorbers can provide detailed information about the amount and physical conditions of material that is participating in the baryon cycle.

  14. Galaxy ecosystems: gas contents, inflows and outflows

    NASA Astrophysics Data System (ADS)

    Lu, Zhankui; Mo, H. J.; Lu, Yu

    2015-06-01

    We use a set of observational data for galaxy cold gas mass fraction and gas phase metallicity to constrain the content, inflow and outflow of gas in central galaxies hosted by haloes with masses between 1011 and 1012 M⊙. The gas contents in high-redshift galaxies are obtained by combining the empirical star formation histories and star formation models that relate star formation rate with the cold gas mass in galaxies. We find that the total baryon mass in low-mass galaxies is always much less than the universal baryon mass fraction since z = 2, regardless of star formation model adopted. The data for the evolution of the gas phase metallicity require net metal outflow at z ≲ 2, and the metal loading factor is constrained to be about 0.01, or about 60 per cent of the metal yield. Based on the assumption that galactic outflow is more enriched in metal than both the interstellar medium and the material ejected at earlier epochs, we are able to put stringent constraints on the upper limits for both the net accretion rate and the net mass outflow rate. The upper limits strongly suggest that the evolution of the gas phase metallicity and gas mass fraction for low-mass galaxies at z < 2 is not compatible with strong outflow. We speculate that the low star formation efficiency of low-mass galaxies is owing to some preventative processes that prevent gas from accreting into galaxies in the first place.

  15. Outflow and hot dust emission in broad absorption line quasars

    SciTech Connect

    Zhang, Shaohua; Zhou, Hongyan; Wang, Huiyuan; Wang, Tinggui; Xing, Feijun; Jiang, Peng; Zhang, Kai E-mail: whywang@mail.ustc.edu.cn

    2014-05-01

    We have investigated a sample of 2099 broad absorption line (BAL) quasars with z = 1.7-2.2 built from the Sloan Digital Sky Survey Data Release Seven and the Wide-field Infrared Survey. This sample is collected from two BAL quasar samples in the literature and is refined by our new algorithm. Correlations of outflow velocity and strength with a hot dust indicator (β{sub NIR}) and other quasar physical parameters—such as an Eddington ratio, luminosity, and a UV continuum slope—are explored in order to figure out which parameters drive outflows. Here β{sub NIR} is the near-infrared continuum slope, which is a good indicator of the amount of hot dust emission relative to the accretion disk emission. We confirm previous findings that outflow properties moderately or weakly depend on the Eddington ratio, UV slope, and luminosity. For the first time, we report moderate and significant correlations of outflow strength and velocity with β{sub NIR} in BAL quasars. It is consistent with the behavior of blueshifted broad emission lines in non-BAL quasars. The statistical analysis and composite spectra study both reveal that outflow strength and velocity are more strongly correlated with β{sub NIR} than the Eddington ratio, luminosity, and UV slope. In particular, the composites show that the entire C IV absorption profile shifts blueward and broadens as β{sub NIR} increases, while the Eddington ratio and UV slope only affect the high and low velocity part of outflows, respectively. We discuss several potential processes and suggest that the dusty outflow scenario, i.e., that dust is intrinsic to outflows and may contribute to the outflow acceleration, is most likely.

  16. Atmospheric Outflows from Hot Jupiters: 2D MHD Simulations

    NASA Astrophysics Data System (ADS)

    Uribe, A.; Matsakos, T.; Konigl, A.

    2015-01-01

    Recent observations of stellar hydrogen Ly-α line absorption during transits of some hot Jupiter exoplanets suggest the presence of a dense, fast wind that is blowing from planetary atmosphere tep{2003Natur.422..143V,2007ApJ...671L..61B}. Modeling efforts include 1D hydrodynamic models tep{2009ApJ...693...23M,2004Icar..170..167Y,2007P&SS...55.1426G} and 2D isothermal magnetized wind models tep{2014arXiv1404.5817T}, among others. In this work, we model the 2D structure of the irradiated upper atmosphere of a hot Jupiter planet and its interaction with the planetary magnetic field. We calculate self consistently the heating by stellar UV radiation and the cooling of the atmosphere by Ly-α emission. We solve for the ionization structure assuming a 100% hydrogen atmosphere, accounting for the radiative ionization, recombination and advection of the gas. We show the effect of stellar tides and planetary magnetic field on the planet outflow and calculate the Ly-α transmission spectra of the resulting atmosphere.

  17. Hot accretion flow with ordered magnetic field, outflow, and saturated conduction

    NASA Astrophysics Data System (ADS)

    Faghei, Kazem

    2013-05-01

    The importance of thermal conduction on hot accretion flow is confirmed by observations of hot gas that surrounds Sgr A∗ and a few other nearby galactic nuclei. On the other hand, the existence of outflow in accretion flows is confirmed by observations and magnetohydrodynamic (MHD) simulations. In this research, we study the influence of both thermal conduction and outflow on hot accretion flows with ordered magnetic field. Since the inner regions of hot accretion flows are, in many cases, collisionless with an electron mean free path due to Coulomb collision larger than the radius, we use a saturated form of thermal conduction, as is appropriate for weakly collisional systems. We also consider the influence of outflow on accretion flow as a sink for mass, and the radial and the angular momentum, and energy taken away from or deposited into the inflow by outflow. The magnetic field is assumed to have a toroidal component and a vertical component as well as a stochastic component. We use a radially self-similar method to solve the integrated equations that govern the behavior of such accretion flows. The solutions show that with an ordered magnetic field, both the surface density and the sound speed decrease, while the radial and angular velocities increase. We found that a hot accretion flow with thermal conduction rotates more quickly and accretes more slowly than that without thermal conduction. Moreover, thermal conduction reduces the influences of the ordered magnetic field on the angular velocities and the sound speed. The study of this model with the magnitude of outflow parameters implies that the gas temperature decreases due to mass, angular momentum, and energy loss. This property of outflow decreases for high thermal conduction.

  18. HOT ELECTROMAGNETIC OUTFLOWS. II. JET BREAKOUT

    SciTech Connect

    Russo, Matthew; Thompson, Christopher

    2013-08-20

    We consider the interaction between radiation, matter, and a magnetic field in a compact, relativistic jet. The entrained matter accelerates outward as the jet breaks out of a star or other confining medium. In some circumstances, such as gamma-ray bursts (GRBs), the magnetization of the jet is greatly reduced by an advected radiation field while the jet is optically thick to scattering. Where magnetic flux surfaces diverge rapidly, a strong outward Lorentz force develops and radiation and matter begin to decouple. The increase in magnetization is coupled to a rapid growth in Lorentz factor. We take two approaches to this problem. The first examines the flow outside the fast magnetosonic critical surface, and calculates the flow speed and the angular distribution of the radiation field over a range of scattering depths. The second considers the flow structure on both sides of the critical surface in the optically thin regime, using a relaxation method. In both approaches, we find how the terminal Lorentz factor and radial profile of the outflow depend on the radiation intensity and optical depth at breakout. The effect of bulk Compton scattering on the radiation spectrum is calculated by a Monte Carlo method, while neglecting the effects of internal dissipation. The peak of the scattered spectrum sits near the seed peak if radiation pressure dominates the acceleration, but is pushed to a higher frequency if the Lorentz force dominates. The unscattered seed radiation can form a distinct, low-frequency component of the spectrum, especially if the magnetic Poynting flux dominates.

  19. Quenching the X-ray spectrum of hot halos with AGN outflows and turbulence

    NASA Astrophysics Data System (ADS)

    Gaspari, M.

    2016-06-01

    I highlight recent advancements in the astrophysics of AGN outflow feedback and diffuse hot gas. Thanks to XMM RGS resolution, we know that the X-ray cores of clusters, groups, and massive galaxies have a strong deficit of soft X-ray emission compared with the classic cooling flow prediction: dL_{x}/dT ∝ (T/T_{hot})^{2±1}. Using 3D hydrodynamic simulations, I show that such deficit arises from the tight self-regulation between thermal instability condensation and AGN outflow feedback. Multiphase filaments condense out of the hot plasma, they rain onto the central SMBH, and boost the AGN outflows via chaotic cold accretion. The sub-relativistic outflows thermalize in the core via shocks and turbulence, releasing more heat in the inner cooler phase, thus inducing the observed soft X-ray decline. I discuss how we can leverage XMM capabilities in the next decade by probing turbulence, conduction, AGN accretion and outflows via the information contained in X-ray spectra and surface brightness. I focus on the importance of selecting a few objects with Ms exposure and how we can unveil multiphase halos through the synergy between simulations and multiwavelength observations.

  20. Hot Jupiter breezes: time-dependent outflows from extrasolar planets

    NASA Astrophysics Data System (ADS)

    Owen, James E.; Adams, Fred C.

    2016-03-01

    We explore the dynamics of magnetically controlled outflows from hot Jupiters, where these flows are driven by UV heating from the central star. In these systems, some of the open field lines do not allow the flow to pass smoothly through the sonic point, so that steady-state solutions do not exist in general. This paper focuses on this type of magnetic field configuration, where the resulting flow becomes manifestly time-dependent. We consider the case of both steady heating and time-variable heating, and find the time-scales for the corresponding time variations of the outflow. Because the flow cannot pass through the sonic transition, it remains subsonic and leads to so-called breeze solutions. One manifestation of the time variability is that the flow samples a collection of different breeze solutions over time, and the mass outflow rate varies in quasi-periodic fashion. Because the flow is subsonic, information can propagate inwards from the outer boundary, which determines, in part, the time-scale of the flow variability. This work finds the relationship between the outer boundary scale and the time-scale of flow variations. In practice, the location of the outer boundary is set by the extent of the sphere of influence of the planet. The measured time variability can be used, in principle, to constrain the parameters of the system (e.g. the strengths of the surface magnetic fields).

  1. Shocked Outflows and Gas Disks in Local Merging Galaxies

    NASA Astrophysics Data System (ADS)

    Soto, Kurt; Martin, C. L.; Prescott, M. K. M.; Armus, L.

    2012-01-01

    We have mapped the kinematic and physical properties of gas emitting optical emission lines across 39 gas-rich mergers, which were previously shown to host tidally-induced gas inflows, with deep ESI spectroscopy. In our unique analysis of these longslit spectra, we fitted multiple kinematic components to forbidden lines and recombination lines simultaneously, enabling an examination of the excitation mechanism in different kinematic components. We identify many rotating gas disks in systems whose stellar component is no longer a disk due to the merger. Many of these disks present gas excited by hot stars, but some of the disks present shock-like ratios of diagnostic emission lines, an observation we attribute to the collision of the two galaxies. In another subset of galaxies, we find very broad (sigma > 150 km/s) emission components that also present shock-like emission-line ratios. The large spatial extent of this emission favors shocks over the narrow-line region of a hidden AGN as the excitation mechanism. The high star formation rate, high dust content, and blueshift of the broad emission further suggest an origin in a galactic outflow. If this interpretation is correct, then our study of these nearby galaxies provides important insight for interpreting the broad emission lines associated with giant star-forming clumps in z 2 galaxies. It also shows that galactic outflows can be recognized via resolved emission lines, in addition to absorption lines, even in integrated spectra; and this technique could prove very powerful for studying galactic outflows in infrared spectra of high-redshift galaxies in the future. This work was supported by the National Science Foundation under contract 0808161.

  2. HOT GAS CLEANUP PROCESS

    EPA Science Inventory

    The report gives results of a study to identify and classify 22 hot gas cleanup (HGC) processes for desulfurizing reducing gases at above 430 C according to absorbent type into groups employing solid, molten salt, and molten metal absorbents. It describes each process in terms of...

  3. NUMERICAL SIMULATION OF HOT ACCRETION FLOWS. II. NATURE, ORIGIN, AND PROPERTIES OF OUTFLOWS AND THEIR POSSIBLE OBSERVATIONAL APPLICATIONS

    SciTech Connect

    Yuan Feng; Bu Defu; Wu Maochun E-mail: dfbu@shao.ac.cn

    2012-12-20

    Hydrodynamical (HD) and magnetohydrodynamical (MHD) numerical simulations of hot accretion flows have indicated that the inflow accretion rate decreases inward. Two models have been proposed to explain this result. In the adiabatic inflow-outflow solution (ADIOS), this is because of the loss of gas in the outflow. In the alternative convection-dominated accretion flow model, it is thought that the flow is convectively unstable and gas is locked in convective eddies. We investigate the nature of the inward decrease of the accretion rate using HD and MHD simulations. We calculate various properties of the inflow and outflow such as temperature and rotational velocity. Systematic and significant differences are found. These results suggest that the inflow and outflow are not simply convective turbulence; instead, systematic inward and outward motion (i.e., real outflow) must exist. We have also analyzed the convective stability of MHD accretion flows and found that they are stable. These results favor the ADIOS scenario. We suggest that the mechanisms of producing outflow in HD and MHD flows are the buoyancy associated with the convection and the centrifugal force associated with the angular momentum transport mediated by the magnetic field, respectively. The latter is similar to the Blandford and Payne mechanism but no large-scale open magnetic field is required. We discuss some possible observational applications, including the Fermi bubble in the Galactic center and winds in active galactic nuclei and black hole X-ray binaries.

  4. The Prevalence of Gas Outflows in Type 2 AGNs. II. 3D Biconical Outflow Models

    NASA Astrophysics Data System (ADS)

    Bae, Hyun-Jin; Woo, Jong-Hak

    2016-09-01

    We present 3D models of biconical outflows combined with a thin dust plane for investigating the physical properties of the ionized gas outflows and their effect on the observed gas kinematics in type 2 active galactic nuclei (AGNs). Using a set of input parameters, we construct a number of models in 3D and calculate the spatially integrated velocity and velocity dispersion for each model. We find that three primary parameters, i.e., intrinsic velocity, bicone inclination, and the amount of dust extinction, mainly determine the simulated velocity and velocity dispersion. Velocity dispersion increases as the intrinsic velocity or the bicone inclination increases, while velocity (i.e., velocity shifts with respect to systemic velocity) increases as the amount of dust extinction increases. Simulated emission-line profiles well reproduce the observed [O iii] line profiles, e.g., narrow core and broad wing components. By comparing model grids and Monte Carlo simulations with the observed [O iii] velocity–velocity dispersion distribution of ∼39,000 type 2 AGNs, we constrain the intrinsic velocity of gas outflows ranging from ∼500 to ∼1000 km s‑1 for the majority of AGNs, and up to ∼1500–2000 km s‑1 for extreme cases. The Monte Carlo simulations show that the number ratio of AGNs with negative [O iii] velocity to AGNs with positive [O iii] velocity correlates with the outflow opening angle, suggesting that outflows with higher intrinsic velocity tend to have wider opening angles. These results demonstrate the potential of our 3D models for studying the physical properties of gas outflows, applicable to various observations, including spatially integrated and resolved gas kinematics.

  5. Mass Outflows from Dissipative Shocks in Hot Accretion Flows

    NASA Astrophysics Data System (ADS)

    Fukumura, Keigo; Kazanas, Demosthenes

    2007-11-01

    We consider stationary, axisymmetric hydrodynamic accretion flows in Kerr geometry. As a plausible means of efficiently separating a small population of nonthermal particles from the bulk accretion flows, we investigate the formation of standing dissipative shocks, i.e., shocks at which fraction of the energy, angular momentum, and mass fluxes do not participate in the shock transition of the flow that accretes onto the compact object but are lost into collimated (jets) or uncollimated (winds) outflows. The mass-loss fraction (at a shock front) is found to vary over a wide range (0%-95%), depending on flow's angular momentum and energy. On the other hand, the associated energy-loss fraction appears to be relatively low (<~1%) for a flow onto a nonrotating black hole case, whereas the fraction could be an order of magnitude higher (<~10%) for a flow onto a rapidly rotating black hole. By estimating the escape velocity of the outflowing particles with a mass-accretion rate relevant for typical active galactic nuclei, we find that nearly 10% of the accreting mass could escape to form an outflow in a disk around a nonrotating black hole, while as much as 50% of the matter may contribute to outflows in a disk around a rapidly rotating black hole. In the context of disk-jet paradigm, our model suggests that shock-driven outflows from accretion can occur in regions not too far from a central engine. Our results imply that a shock front under some conditions could serve as a plausible site where (nonthermal) seed particles of the outflows (jets/winds) are efficiently decoupled from bulk accretion.

  6. Mass Outflows from Dissipative Shocks in Hot Accretion Flows

    NASA Astrophysics Data System (ADS)

    Fukumura, Keigo; Kazanas, D.

    2007-05-01

    We consider stationary, axisymmetric hydrodynamic accretion flows in Kerr geometry. As a plausible means of efficiently separating small population of nonthermal particles from the bulk accretion flows, we investigate the formation of dissipative standing shocks where energy, angular momentum and mass are partially lost into collimated (jets) or uncollimated (winds) outflows subsequently. Mass loss fraction (at a shock front) is found to vary over a wide range (0% - 95%) depending on flow's angular momentum and energy. On the other hand, energy loss fraction appears to be relatively low (<1%) for a non-rotating black hole case, whereas the fraction could be an order of magnitude higher (<10%) for a rapidly-rotating black hole case. By estimating the escape velocity of the outflowing particles, we find that nearly 10% of the accreting mass (decoupled from the bulk accretion flows) could participate in forming the outflows around a non-rotating black hole, while as much as 50% of the matter may contribute to the outflows around a rapidly-rotating black hole. In the context of disk-jet paradigm, our model suggests that shock-driven outflows from accretion can occur in regions not too far from a central engine (within 2-40 gravitational radii), as observed in some active galaxies (e.g., M87 and 3C120). Slope of radial density profile for upstream flows is found to be -3/2 as in advection-dominated accretion flow (ADAF) solution while that for downstream flows is as steep as -5/2. Our results imply that a shock front under some conditions could serve as a plausible site where seed particles of the outflows (jets/winds) are efficiently decoupled from bulk accretion.

  7. HOT GAS HALOS IN EARLY-TYPE FIELD GALAXIES

    SciTech Connect

    Mulchaey, John S.; Jeltema, Tesla E. E-mail: tesla@ucolick.or

    2010-05-20

    We use Chandra and XMM-Newton to study the hot gas content in a sample of field early-type galaxies. We find that the L {sub X}-L {sub K} relationship is steeper for field galaxies than for comparable galaxies in groups and clusters. The low hot gas content of field galaxies with L {sub K} {approx_lt} L {sub *} suggests that internal processes such as supernovae-driven winds or active galactic nucleus feedback expel hot gas from low-mass galaxies. Such mechanisms may be less effective in groups and clusters where the presence of an intragroup or intracluster medium can confine outflowing material. In addition, galaxies in groups and clusters may be able to accrete gas from the ambient medium. While there is a population of L {sub K} {approx_lt} L {sub *} galaxies in groups and clusters that retain hot gas halos, some galaxies in these rich environments, including brighter galaxies, are largely devoid of hot gas. In these cases, the hot gas halos have likely been removed via ram pressure stripping. This suggests a very complex interplay between the intragroup/intracluster medium and hot gas halos of galaxies in rich environments, with the ambient medium helping to confine or even enhance the halos in some cases and acting to remove gas in others. In contrast, the hot gas content of more isolated galaxies is largely a function of the mass of the galaxy, with more massive galaxies able to maintain their halos, while in lower mass systems the hot gas escapes in outflowing winds.

  8. Enviropower hot gas desulfurization pilot

    SciTech Connect

    Ghazanfari, R.; Feher, G.; Konttinen, J.; Ghazanfari, R.; Lehtovaara, A.; Mojtahedi, W.

    1994-11-01

    The objectives of the project are to develop and demonstrate (1) hydrogen sulfide removal using regenerable zinc titanate sorbent in pressurized fluidized bed reactors, (2) recovery of the elemental sulfur from the tail-gas of the sorbent regenerator and (3) hot gas particulate removal system using ceramic candle filters. Results are presented on pilot plant design and testing and modeling efforts.

  9. Hot Gas Flows in T Tauri Stars

    NASA Astrophysics Data System (ADS)

    Ardila, David R.; Herczeg, G.; Gregory, S. G.; Ingleby, L.; France, K.; Brown, A.; Edwards, S.; Linsky, J.; Yang, H.; Valenti, J. A.; Johns-Krull, C. M.; Alexander, R.; Bergin, E. A.; Bethell, T.; Brown, J.; Calvet, N.; Espaillat, C.; Hervé, A.; Hillenbrand, L.; Hussain, G.; Roueff, E.; Schindhelm, E.; Walter, F. M.

    2013-01-01

    We describe observations of the hot gas 1e5 K) ultraviolet lines C IV and He II, in Classical and Weak T Tauri Stars (CTTSs, WTTSs). Our goal is to provide observational constraints for realistic models. Most of the data for this work comes from the Hubble proposal “The Disks, Accretion, and Outflows (DAO) of T Tau stars” (PI Herczeg). The DAO program is the largest and most sensitive high resolution spectroscopic survey of young stars in the UV ever undertaken and it provides a rich source of information for these objects. The sample of high resolution COS and STIS spectra presented here comprises 35 stars: one Herbig Ae star, 28 CTTSs, and 6 WTTSs. For CTTSs, the lines consist of two kinematic components. The relative strengths of the narrow and broad components (NC, BC) are similar in C IV but in He II the NC is stronger than the BC, and dominates the line profile. We do not find correlations between disk inclination and the velocity centroid, width, or shape of the CIV line profile. The NC of the C IV line in CTTSs increases in strength with accretion rate, and its contribution to the line increases from ˜20% to ˜80%, for the accretion rates considered here (1e-10 to 1e-7 Msun/yr). The CTTSs C IV lines are redshifted by ˜20 km/s while the CTTSs He II are redshifted by ˜10 km/s. Because the He II line and the C IV NC have the same width in CTTSs and in WTTSs, but are correlated with accretion, we suggest that they are produced in the stellar transition region. The accretion shock model predicts that the velocity of the post-shock emission should be 4x smaller than the velocity of the pre-shock emission. Identifying the post-shock emission with the NC and the pre-shock with the BC, we find that this is approximately the case in 11 out of 23 objects. The model cannot explain 11 systems in which the velocity of the NC is smaller than the velocity of the BC, or systems in which one of the velocities is negative (five CTTSs). The hot gas lines in some systems

  10. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    E.S. Connolly; G.D. Forsythe

    1998-12-22

    Advanced, coal-based power plants will require durable and reliable hot gas filtration systems to remove particulate contaminants from the gas streams to protect downstream components such as turbine blades from erosion damage. It is expected that the filter elements in these systems will have to be made of ceramic materials to withstand goal service temperatures of 1600 F or higher. Recent demonstration projects and pilot plant tests have indicated that the current generation of ceramic hot gas filters (cross-flow and candle configurations) are failing prematurely. Two of the most promising materials that have been extensively evaluated are clay-bonded silicon carbide and alumina-mullite porous monoliths. These candidates, however, have been found to suffer progressive thermal shock fatigue damage, as a result of rapid cooling/heating cycles. Such temperature changes occur when the hot filters are back-pulsed with cooler gas to clean them, or in process upset conditions, where even larger gas temperature changes may occur quickly and unpredictably. In addition, the clay-bonded silicon carbide materials are susceptible to chemical attack of the glassy binder phase that holds the SiC particles together, resulting in softening, strength loss, creep, and eventual failure.

  11. Microbial communities and arsenic biogeochemistry at the outflow of an alkaline sulfide-rich hot spring

    PubMed Central

    Jiang, Zhou; Li, Ping; Van Nostrand, Joy D.; Zhang, Ping; Zhou, Jizhong; Wang, Yanhong; Dai, Xinyue; Zhang, Rui; Jiang, Dawei; Wang, Yanxin

    2016-01-01

    Alkaline sulfide-rich hot springs provide a unique environment for microbial community and arsenic (As) biogeochemistry. In this study, a representative alkaline sulfide-rich hot spring, Zimeiquan in the Tengchong geothermal area, was chosen to study arsenic geochemistry and microbial community using Illumina MiSeq sequencing. Over 0.26 million 16S rRNA sequence reads were obtained from 5-paired parallel water and sediment samples along the hot spring’s outflow channel. High ratios of As(V)/AsSum (total combined arsenate and arsenite concentrations) (0.59–0.78), coupled with high sulfide (up to 5.87 mg/L), were present in the hot spring’s pools, which suggested As(III) oxidation occurred. Along the outflow channel, AsSum increased from 5.45 to 13.86 μmol/L, and the combined sulfide and sulfate concentrations increased from 292.02 to 364.28 μmol/L. These increases were primarily attributed to thioarsenic transformation. Temperature, sulfide, As and dissolved oxygen significantly shaped the microbial communities between not only the pools and downstream samples, but also water and sediment samples. Results implied that the upstream Thermocrinis was responsible for the transformation of thioarsenic to As(III) and the downstream Thermus contributed to derived As(III) oxidation. This study improves our understanding of microbially-mediated As transformation in alkaline sulfide-rich hot springs. PMID:27126380

  12. Microbial communities and arsenic biogeochemistry at the outflow of an alkaline sulfide-rich hot spring

    NASA Astrophysics Data System (ADS)

    Jiang, Zhou; Li, Ping; van Nostrand, Joy D.; Zhang, Ping; Zhou, Jizhong; Wang, Yanhong; Dai, Xinyue; Zhang, Rui; Jiang, Dawei; Wang, Yanxin

    2016-04-01

    Alkaline sulfide-rich hot springs provide a unique environment for microbial community and arsenic (As) biogeochemistry. In this study, a representative alkaline sulfide-rich hot spring, Zimeiquan in the Tengchong geothermal area, was chosen to study arsenic geochemistry and microbial community using Illumina MiSeq sequencing. Over 0.26 million 16S rRNA sequence reads were obtained from 5-paired parallel water and sediment samples along the hot spring’s outflow channel. High ratios of As(V)/AsSum (total combined arsenate and arsenite concentrations) (0.59–0.78), coupled with high sulfide (up to 5.87 mg/L), were present in the hot spring’s pools, which suggested As(III) oxidation occurred. Along the outflow channel, AsSum increased from 5.45 to 13.86 μmol/L, and the combined sulfide and sulfate concentrations increased from 292.02 to 364.28 μmol/L. These increases were primarily attributed to thioarsenic transformation. Temperature, sulfide, As and dissolved oxygen significantly shaped the microbial communities between not only the pools and downstream samples, but also water and sediment samples. Results implied that the upstream Thermocrinis was responsible for the transformation of thioarsenic to As(III) and the downstream Thermus contributed to derived As(III) oxidation. This study improves our understanding of microbially-mediated As transformation in alkaline sulfide-rich hot springs.

  13. Microbial communities and arsenic biogeochemistry at the outflow of an alkaline sulfide-rich hot spring.

    PubMed

    Jiang, Zhou; Li, Ping; Van Nostrand, Joy D; Zhang, Ping; Zhou, Jizhong; Wang, Yanhong; Dai, Xinyue; Zhang, Rui; Jiang, Dawei; Wang, Yanxin

    2016-01-01

    Alkaline sulfide-rich hot springs provide a unique environment for microbial community and arsenic (As) biogeochemistry. In this study, a representative alkaline sulfide-rich hot spring, Zimeiquan in the Tengchong geothermal area, was chosen to study arsenic geochemistry and microbial community using Illumina MiSeq sequencing. Over 0.26 million 16S rRNA sequence reads were obtained from 5-paired parallel water and sediment samples along the hot spring's outflow channel. High ratios of As(V)/AsSum (total combined arsenate and arsenite concentrations) (0.59-0.78), coupled with high sulfide (up to 5.87 mg/L), were present in the hot spring's pools, which suggested As(III) oxidation occurred. Along the outflow channel, AsSum increased from 5.45 to 13.86 μmol/L, and the combined sulfide and sulfate concentrations increased from 292.02 to 364.28 μmol/L. These increases were primarily attributed to thioarsenic transformation. Temperature, sulfide, As and dissolved oxygen significantly shaped the microbial communities between not only the pools and downstream samples, but also water and sediment samples. Results implied that the upstream Thermocrinis was responsible for the transformation of thioarsenic to As(III) and the downstream Thermus contributed to derived As(III) oxidation. This study improves our understanding of microbially-mediated As transformation in alkaline sulfide-rich hot springs. PMID:27126380

  14. Hot gas engine heater head

    DOEpatents

    Berntell, John O.

    1983-01-01

    A heater head for a multi-cylinder double acting hot gas engine in which each cylinder is surrounded by an annular regenerator unit, and in which the tops of each cylinder and its surrounding regenerator are interconnected by a multiplicity of heater tubes. A manifold for the heater tubes has a centrally disposed duct connected to the top of the cylinder and surrounded by a wider duct connecting the other ends of the heater tubes with the regenerator unit.

  15. HOT CORE, OUTFLOWS, AND MAGNETIC FIELDS IN W43-MM1 (G30.79 FIR 10)

    SciTech Connect

    Sridharan, T. K.; Qiu, K.; Li, H.; Pillai, T.; Patel, N. A.; Zhang, Q.; Rao, R.; Cortes, P.

    2014-03-10

    We present submillimeter spectral line and dust continuum polarization observations of a remarkable hot core and multiple outflows in the high-mass, star-forming region W43-MM1 (G30.79 FIR 10), obtained using the Submillimeter Array. A temperature of ∼400 K is estimated for the hot core using CH{sub 3}CN (J = 19-18) lines, with detections of 11 K-ladder components. The high temperature and the mass estimates for the outflows indicate high-mass star formation. The continuum polarization pattern shows an ordered distribution, and its orientation over the main outflow appears to be aligned with the outflow. The derived magnetic field indicates slightly super-critical conditions. While the magnetic and outflow energies are comparable, the B-field orientation appears to have changed from parsec scales to ∼0.1 pc scales during the core/star formation process.

  16. A HOT MOLECULAR OUTFLOW DRIVEN BY THE IONIZED JET ASSOCIATED WITH IRAS 16562-3959

    SciTech Connect

    Guzman, Andres E.; Garay, Guido; Rathborne, Jill; Brooks, Kate J.; Guesten, Rolf

    2011-08-01

    We report molecular line observations in the CO J = 3 {yields} 2, 6 {yields} 5, and 7 {yields} 6 transitions, made using the Atacama Pathfinder Experiment Telescope, toward the massive and dense core IRAS 16562-3959. This core harbors a string of radio sources thought to be powered by a central collimated jet of ionized gas. The molecular observations show the presence of high-velocity gas exhibiting a quadrupolar morphology, most likely produced by the presence of two collimated outflows. The southeast-northwest (SE-NW) molecular outflow is aligned with the string of radio continuum sources, suggesting it is driven by the jet. We find that the excitation temperature of the gas in the SE-NW outflow is high, with values of 145 and 120 K for the blueshifted and redshifted lobes, respectively. This outflow has a total mass of 1.92 M{sub sun}, a total momentum of {approx}89 M{sub sun} km s{sup -1}, and an averaged momentum rate of {approx}3.0 x 10{sup -2} M{sub sun} km s{sup -1} yr{sup -1}, values characteristic of flows driven by young massive stellar objects with high luminosities (L{sub bol} {approx} 2 x 10{sup 4} L{sub sun}). Complementary data taken with the Atacama Submillimeter Telescope Experiment in high density and shock tracers support the picture that IRAS 16562-3959 is an accreting young massive star associated with an ionized jet, which is the energy source of a molecular outflow.

  17. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    Matthew R. June; John L. Hurley; Mark W. Johnson

    1999-04-01

    Iron aluminide hot gas filters have been developed using powder metallurgy techniques to form seamless cylinders. Three alloys were short-term corrosion tested in simulated IGCC atmospheres with temperatures between 925 F and 1200 F with hydrogen sulfide concentrations ranging from 783 ppm{sub v} to 78,300 ppm{sub v}. Long-term testing was conducted for 1500 hours at 925 F with 78,300 ppm{sub v}. The FAS and FAL alloys were found to be corrosion resistant in the simulated environments. The FAS alloy has been commercialized.

  18. Assessment of hot gas contaminant control

    SciTech Connect

    Rutkowski, M.D.; Klett, M.G.; Zaharchuk, R.

    1996-12-31

    The objective of this work is to gather data and information to assist DOE in responding to the NRC recommendation on hot gas cleanup by performing a comprehensive assessment of hot gas cleanup systems for advanced coal-based Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) including the status of development of the components of the hot gas cleanup systems, and the probable cost and performance impacts. The scope and time frame of information gathering is generally responsive to the boundaries set by the National Research council (NRC), but includes a broad range of interests and programs which cover hot gas cleanup through the year 2010. As the status of hot gas cleanup is continually changing, additional current data and information are being obtained for this effort from this 1996 METC Contractors` Review Meeting as well as from the 1996 Pittsburgh Coal Conference, and the University of Karlsruhe Symposium. The technical approach to completing this work consists of: (1) Determination of the status of hot gas cleanup technologies-- particulate collection systems, hot gas desulfurization systems, and trace contaminant removal systems; (2) Determination of hot gas cleanup systems cost and performance sensitivities. Analysis of conceptual IGCC and PFBC plant designs with hot gas cleanup have been performed. The impact of variations in hot gas cleanup technologies on cost and performance was evaluated using parametric analysis of the baseline plant designs and performance sensitivity.

  19. AGN-stimulated cooling of hot gas in elliptical galaxies

    NASA Astrophysics Data System (ADS)

    Valentini, Milena; Brighenti, Fabrizio

    2015-04-01

    We study the impact of relatively weak active galactic nucleus (AGN) feedback on the interstellar medium (ISM) of intermediate and massive elliptical galaxies. We find that the AGN activity, while globally heating the ISM, naturally stimulates some degree of hot gas cooling on scales of several kpc. This process generates the persistent presence of a cold ISM phase, with mass ranging between 104 and ≳ 5 × 107 M⊙, where the latter value is appropriate for group centred, massive galaxies. Widespread cooling occurs where the ratio of cooling to free-fall time before the activation of the AGN feedback satisfies tcool/tff ≲ 70, that is we find a less restrictive threshold than commonly quoted in the literature. This process helps explaining the body of observations of cold gas (both ionized and neutral/molecular) in Ellipticals and, perhaps, the residual star formation detected in many early-type galaxies. The amount and distribution of the off-centre cold gas vary irregularly with time. The cold ISM velocity field is irregular, initially sharing the (outflowing) turbulent hot gas motion. Typical velocity dispersions of the cold gas lie in the range 100-200 km s-1. Freshly generated cold gas often forms a cold outflow and can appear kinematically misaligned with respect to the stars. We also follow the dust evolution in the hot and cold gas. We find that the internally generated cold ISM has a very low dust content, with representative values of the dust-to-gas ratio of 10-4-10-5. Therefore, this cold gas can escape detection in the traditional dust-absorption maps.

  20. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    E.S. Connolly; G.D. Forsythe

    2000-09-30

    DuPont Lanxide Composites, Inc. undertook a sixty-month program, under DOE Contract DEAC21-94MC31214, in order to develop hot gas candle filters from a patented material technology know as PRD-66. The goal of this program was to extend the development of this material as a filter element and fully assess the capability of this technology to meet the needs of Pressurized Fluidized Bed Combustion (PFBC) and Integrated Gasification Combined Cycle (IGCC) power generation systems at commercial scale. The principal objective of Task 3 was to build on the initial PRD-66 filter development, optimize its structure, and evaluate basic material properties relevant to the hot gas filter application. Initially, this consisted of an evaluation of an advanced filament-wound core structure that had been designed to produce an effective bulk filter underneath the barrier filter formed by the outer membrane. The basic material properties to be evaluated (as established by the DOE/METC materials working group) would include mechanical, thermal, and fracture toughness parameters for both new and used material, for the purpose of building a material database consistent with what is being done for the alternative candle filter systems. Task 3 was later expanded to include analysis of PRD-66 candle filters, which had been exposed to actual PFBC conditions, development of an improved membrane, and installation of equipment necessary for the processing of a modified composition. Task 4 would address essential technical issues involving the scale-up of PRD-66 candle filter manufacturing from prototype production to commercial scale manufacturing. The focus would be on capacity (as it affects the ability to deliver commercial order quantities), process specification (as it affects yields, quality, and costs), and manufacturing systems (e.g. QA/QC, materials handling, parts flow, and cost data acquisition). Any filters fabricated during this task would be used for product qualification tests

  1. Ceramic hot-gas filter

    DOEpatents

    Connolly, E.S.; Forsythe, G.D.; Domanski, D.M.; Chambers, J.A.; Rajendran, G.P.

    1999-05-11

    A ceramic hot-gas candle filter is described having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during back pulse cleaning and is resistant to chemical degradation at high temperatures.

  2. Ceramic hot-gas filter

    DOEpatents

    Connolly, Elizabeth Sokolinski; Forsythe, George Daniel; Domanski, Daniel Matthew; Chambers, Jeffrey Allen; Rajendran, Govindasamy Paramasivam

    1999-01-01

    A ceramic hot-gas candle filter having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during backpulse cleaning and is resistant to chemical degradation at high temperatures.

  3. Hot/Warm Gas Cleanup

    SciTech Connect

    Bissett, Larry A.

    2001-11-06

    Using regenerable sorbents and transport or fluid-bed contacting, the Gas Process Development Unit (GPDU) at NETL-Morgantown will be used to demonstrate the process feasibility of removing sulfur from coal gasification or other fuel gas streams at temperatures above dew point of the gas. This technology, also known as hot or warm gas desulfurization, is expected to remove sulfur to concentrations lower than conventional systems at comparable cost. The project was constructed under the U.S. Department of Energy (DOE) Integrated Gasification Combined Cycle (IGCC) power system program and is an ''enabling technology'' in the Vision 21 program. The GPDU was designed to be the smallest scale research and development facility capable of providing viable scale-up design data for new integrated transport or fluid-bed desulfurization processes. With the capability to test at process conditions representative of anticipated commercial applications in terms of temperatures, pressures, major compositions, velocities, and sorbent cycling, the unit is expected to generate important information on process control, configuration, and sorbent suitability. In this way, the GPDU fills a strategic role between past/current small-scale testing and large-scale demonstrations. A primary objective of the project is to gain insight into which reactor combination (i.e., both transport, both fluid bed, or mixed) is more suitable for desulfurization technology and why. Assuming process feasibility is demonstrated, this guides future development or commercial ventures by answering the question of what to build, and provides performance and scale-up data (e.g., required transport reactor densities). Another important objective, which naturally derives from the process development activities, is demonstration of sorbent suitability and readiness for commercial deployment (e.g., sorbent attrition and cycle life). In this sense, the GPDU can serve as a final testing ground to reduce the risks of

  4. The Properties of Diffuse Warm and Hot Gas in I Zw 18

    NASA Astrophysics Data System (ADS)

    Bomans, D. J.

    With their generally low metallicity and shallow potential wells, low mass galaxies are especially well suited laboratories for the interplay between gas and stars. Even moderate star formation events effect large parts of the host system and outflows of warm and hot gas with freshly produced metals appear to be relatively common. In addition the cooling rate of the hot gas in the outflows should be depressed as effect of the low metallicity. While the study of the creation and transport of the hot gas and the interaction between hot and colder gas needs X-ray data, relatively little data are available in the literature for dwarf galaxies, yet. Here we present a case study of the diffuse hot gas of I Zw 18 using CHANDRA ACIS-S imaging and spectroscopy. The X-ray results are compared with HST imaging and long-slit echelle spectroscopy of the warm diffuse gas. I Zw 18 is an especially well suited target due to extremely low metallicity, relatively high current star formation rate, and low mass. Narrow band imaging and echelle spectroscopy demonstrate that gas is flowing out of the galaxy. The low metallicity should aid the detection of metallicity differences between the galaxy and the hot, possibly metal-enriched gas on its way out of the host galaxy. The ACIS-S spectrum is discussed in this respect.

  5. HUBBLE PICTURES SHOW HOT GAS BUBBLE EJECTED BY YOUNG STAR

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images taken with the Hubble Space Telescope's Wide Field and Planetary Camera 2 reveal the evolution of bubbles of glowing gas being blown out from the young binary star system XZ Tauri. Gas from an unseen disk around one or both of the stars is channeled through magnetic fields surrounding the binary system and then is forced out into space at nearly 300,000 miles per hour (540,000 kilometers per hour). This outflow, which is only about 30 years old, extends nearly 60 billion miles (96 billion kilometers). Hubble first discovered this unique bubble in 1995, and additional observations were made between 1998 and 2000. These images show that there was a dramatic change in its appearance between 1995 and 1998. In 1995, the bubble's edge was the same brightness as its interior. However, when Hubble took another look at XZ Tauri in 1998, the edge was suddenly brighter. This brightening is probably caused by the hot gas cooling off, which allows electrons in the gas to recombine with atoms, a process that gives off light. This is the first time that astronomers have seen such a cooling zone 'turn on.' These images provide an unprecedented opportunity to study the development of a very recent outflow from young (about 1 million years old) stars. Credits: NASA, John Krist (Space Telescope Science Institute), Karl Stapelfeldt (Jet Propulsion Laboratory), Jeff Hester (Arizona State University), Chris Burrows (European Space Agency/Space Telescope Science Institute)

  6. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    RICHARD A. WAGNER

    1998-09-04

    This report describes the fabrication and testing of continuous fiber ceramic composite (CFCC) based hot gas filters. The fabrication approach utilized a modified filament winding method that combined both continuous and chopped fibers into a novel microstructure. The work was divided into five primary tasks. In the first task, a preliminary set of compositions was fabricated in the form of open end tubes and characterized. The results of this task were used to identify the most promising compositions for sub-scale filter element fabrication and testing. In addition to laboratory measurements of permeability and strength, exposure testing in a coal combustion environment was performed to asses the thermo-chemical stability of the CFCC materials. Four candidate compositions were fabricated into sub-scale filter elements with integral flange and a closed end. Following the 250 hour exposure test in a circulating fluid bed combustor, the retained strength ranged from 70 t 145 percent of the as-fabricated strength. The post-test samples exhibited non-catastrophic failure behavior in contrast to the brittle failure exhibited by monolithic materials. Filter fabrication development continued in a filter improvement and cost reduction task that resulted in an improved fiber architecture, the production of a net shape flange, and an improved low cost bond. These modifications were incorporated into the process and used to fabricate 50 full-sized filter elements for testing in demonstration facilities in Karhula, Finland and at the Power Systems Development Facility (PSDF) in Wilsonville, AL. After 581 hours of testing in the Karhula facility, the elements retained approximately 87 percent of their as-fabricated strength. In addition, mechanical response testing at Virginia Tech provided a further demonstration of the high level of strain tolerance of the vacuum wound filter elements. Additional testing in the M. W. Kellogg unit at the PSDF has accumulated over 1800 hours of

  7. Hot gas filter and system assembly

    DOEpatents

    Lippert, Thomas Edwin; Palmer, Kathryn Miles; Bruck, Gerald Joseph; Alvin, Mary Anne; Smeltzer, Eugene E.; Bachovchin, Dennis Michael

    1999-01-01

    A filter element for separating fine dirty particles from a hot gas. The filter element comprises a first porous wall and a second porous wall. Each porous wall has an outer surface and an inner surface. The first and second porous walls being coupled together thereby forming a substantially closed figure and open at one end. The open end is formed to be coupled to a hot gas clean up system support structure. The first and second porous walls define a channel beginning at the open end and terminate at the closed end through which a filtered clean gas can flow through and out into the clean gas side of a hot gas clean up system.

  8. Hot gas filter and system assembly

    DOEpatents

    Lippert, T.E.; Palmer, K.M.; Bruck, G.J.; Alvin, M.A.; Smeltzer, E.E.; Bachovchin, D.M.

    1999-08-31

    A filter element is described for separating fine dirty particles from a hot gas. The filter element comprises a first porous wall and a second porous wall. Each porous wall has an outer surface and an inner surface. The first and second porous walls being coupled together thereby forming a substantially closed figure and open at one end. The open end is formed to be coupled to a hot gas clean up system support structure. The first and second porous walls define a channel beginning at the open end and terminate at the closed end through which a filtered clean gas can flow through and out into the clean gas side of a hot gas clean up system. 8 figs.

  9. Hot Gas in the Large Magellanic Cloud

    NASA Technical Reports Server (NTRS)

    Chu, You-Hua

    2000-01-01

    The Large Magellanic Cloud (LMC) offers an excellent laboratory to study the physical structure of the interstellar medium (ISM) because of its proximity, nearly face-on orientation, and small foreground and internal extinction. Optical and radio surveys of the LMC ISM have revealed interstellar structures of sizes ranging from a few parsecs to over 1000 parsecs. ROSAT X-ray mosaics of the LMC have detected abundant 10 (exp 6) K hot gas, some of which is bounded by large shell structures while the rest, does not appear to be associated with any visible interstellar structure. The X-ray observations have been analyzed to determine the physical conditions of the hot gas. The distribution of the hot gas can be compared to those of the cooler gas and massive stars, in order to determine the production mechanism of the hot gas. UV observations of interstellar absorption lines of high ions, such as C IV, N V, and O VI, can be used to study the interfaces between the 10 (exp 6) K gas and cooler ionized gas, and to provide constraints on the location of 10 (exp 6) K gas with respect to the cooler gas along the line of sight.

  10. Dust In Hell: Discovery Of Dust In Hot Gas Around Group-Centered Elliptical Galaxies

    NASA Astrophysics Data System (ADS)

    Temi, Pasquale; Brighenti, F.; Mathews, W. G.

    2007-05-01

    Observations with the Spitzer infrared telescope reveal extended internally produced dust in the hot gas (KT 1 KeV) atmospheres surrounding two optically normal galaxies, NGC 5044 and NGC 4636. We interpret this as a dusty buoyant outflow resulting from energy released by gas accretion onto supermassive black holes in the galaxy cores. Both galaxies have highly disturbed, transient activities in the hot gas and contain strong dust emission at 70 and 160 microns in excess of what expected from normal stellar mass loss. The 70 micron image is clearly extended. The lifetime of dust in hot (KT=1KeV) interstellar gas to destruction by sputtering (ion impacts), 10 million years, establishes the time when the dust first entered the hot gas. Remarkably, in NGC 5044 we observe interstellar PAH dust-molecular emission at 8 microns out to about 5 Kpc that is spatially coincident with extended Halpha+[NII] emission from warm gas. We propose that this dust comes from the destruction and heating of dusty disks in the nuclei of these galaxies, followed by buoyant transport. A simple calculation shows that dust-assisted cooling in outflowing buoyant gas in NGC 5044 can cool the gas within a few Kpc in about 10 million years, explaining the optical line emission observed.

  11. ALMA OBSERVATIONS OF THE IRDC CLUMP G34.43+00.24 MM3: HOT CORE AND MOLECULAR OUTFLOWS

    SciTech Connect

    Sakai, Takeshi; Sakai, Nami; Yamamoto, Satoshi; Foster, Jonathan B.; Sanhueza, Patricio; Jackson, James M.; Kassis, Marc; Furuya, Kenji; Aikawa, Yuri; Hirota, Tomoya

    2013-09-20

    We have observed a cluster forming clump (MM3) associated with the infrared dark cloud G34.43+00.24 in the 1.3 mm continuum and the CH{sub 3}OH, CS, {sup 13}CS, SiO, CH{sub 3}CH{sub 2}CN, and HCOOCH{sub 3} lines with the Atacama Large Millimeter/submillimeter Array and in K-band with the Keck telescope. We have found a young outflow toward the center of this clump in the SiO, CS, and CH{sub 3}OH lines. This outflow is likely driven by a protostar embedded in a hot core, which is traced by the CH{sub 3}CH{sub 2}CN, HCOOCH{sub 3}, {sup 13}CS, and high excitation CH{sub 3}OH lines. The size of the hot core is about 800 × 300 AU in spite of its low mass (<1.1 M {sub ☉}), suggesting a high accretion rate or the presence of multiple star system harboring a few hot corinos. The outflow is highly collimated, and the dynamical timescale is estimated to be less than 740 yr. In addition, we have also detected extended emission of SiO, CS, and CH{sub 3}OH, which is not associated with the hot core and the outflow. This emission may be related to past star formation activity in the clump. Although G34.43+00.24 MM3 is surrounded by a dark feature in infrared, it has already experienced active formation of low-mass stars in an early stage of clump evolution.

  12. Chandra Galaxy Atals - Global Hot Gas Properties

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Woo; Anderson, Craig; Burke, Douglas J.; Fabbiano, Giuseppina; Fruscione, Antonella; Lauer, Jennifer L.; McCollough, Michael L.; Morgan, Douglas; Mossman, Amy; O'Sullivan, Ewan; Paggi, Alessandro; Trinchieri, Ginevra

    2016-04-01

    The hot gas in early type galaxies (ETGs) plays a crucial role in understanding their formation and evolution. As the hot gas is often extended to the outskirts beyond the optical size, the large scale structural features identified by Chandra (including jets, cavities, cold fronts, filaments and tails) point to key evolutionary mechanisms, e.g., AGN feedback, merging history, accretion/stripping and star formation and its quenching. In our new project, the Chandra Galaxy Atlas, we systematically analyze the archival Chandra data of ~100 ETGs to study the hot ISM. Using uniformly derived data products with spatially resolved spectral information, we will present gas morphology, scaling relations and X-ray based mass profiles and address their implications.

  13. HOT GAS LINES IN T TAURI STARS

    SciTech Connect

    Ardila, David R.; Herczeg, Gregory J.; Gregory, Scott G.; Hillenbrand, Lynne A.; Ingleby, Laura; Bergin, Edwin; Bethell, Thomas; Calvet, Nuria; France, Kevin; Brown, Alexander; Edwards, Suzan; Johns-Krull, Christopher; Linsky, Jeffrey L.; Yang, Hao; Valenti, Jeff A.; Abgrall, Herve; Alexander, Richard D.; Brown, Joanna M.; Espaillat, Catherine; Hussain, Gaitee; and others

    2013-07-01

    For Classical T Tauri Stars (CTTSs), the resonance doublets of N V, Si IV, and C IV, as well as the He II 1640 A line, trace hot gas flows and act as diagnostics of the accretion process. In this paper we assemble a large high-resolution, high-sensitivity data set of these lines in CTTSs and Weak T Tauri Stars (WTTSs). The sample comprises 35 stars: 1 Herbig Ae star, 28 CTTSs, and 6 WTTSs. We find that the C IV, Si IV, and N V lines in CTTSs all have similar shapes. We decompose the C IV and He II lines into broad and narrow Gaussian components (BC and NC). The most common (50%) C IV line morphology in CTTSs is that of a low-velocity NC together with a redshifted BC. For CTTSs, a strong BC is the result of the accretion process. The contribution fraction of the NC to the C IV line flux in CTTSs increases with accretion rate, from {approx}20% to up to {approx}80%. The velocity centroids of the BCs and NCs are such that V{sub BC} {approx}> 4 V{sub NC}, consistent with the predictions of the accretion shock model, in at most 12 out of 22 CTTSs. We do not find evidence of the post-shock becoming buried in the stellar photosphere due to the pressure of the accretion flow. The He II CTTSs lines are generally symmetric and narrow, with FWHM and redshifts comparable to those of WTTSs. They are less redshifted than the CTTSs C IV lines, by {approx}10 km s{sup -1}. The amount of flux in the BC of the He II line is small compared to that of the C IV line, and we show that this is consistent with models of the pre-shock column emission. Overall, the observations are consistent with the presence of multiple accretion columns with different densities or with accretion models that predict a slow-moving, low-density region in the periphery of the accretion column. For HN Tau A and RW Aur A, most of the C IV line is blueshifted suggesting that the C IV emission is produced by shocks within outflow jets. In our sample, the Herbig Ae star DX Cha is the only object for which we find a

  14. Evolution of Hot Gas in Elliptical Galaxies

    NASA Technical Reports Server (NTRS)

    Mathews, William G.

    2004-01-01

    This theory grant was awarded to study the curious nature, origin and evolution of hot gas in elliptical galaxies and their surrounding groups. Understanding the properties of this X-ray emitting gas has profound implications over the broad landscape of modern astrophysics: cosmology, galaxy formation, star formation, cosmic metal enrichment, galactic structure and dynamics, and the physics of hot gases containing dust and magnetic fields. One of our principal specific objectives was to interpret the marvelous new observations from the XMM and Chandru satellite X-ray telescopes.

  15. Multi-cylinder hot gas engine

    DOEpatents

    Corey, John A.

    1985-01-01

    A multi-cylinder hot gas engine having an equal angle, V-shaped engine block in which two banks of parallel, equal length, equally sized cylinders are formed together with annular regenerator/cooler units surrounding each cylinder, and wherein the pistons are connected to a single crankshaft. The hot gas engine further includes an annular heater head disposed around a central circular combustor volume having a new balanced-flow hot-working-fluid manifold assembly that provides optimum balanced flow of the working fluid through the heater head working fluid passageways which are connected between each of the cylinders and their respective associated annular regenerator units. This balanced flow provides even heater head temperatures and, therefore, maximum average working fluid temperature for best operating efficiency with the use of a single crankshaft V-shaped engine block.

  16. CONOCO DOLOMITE HOT GAS CLEANUP SYSTEM

    EPA Science Inventory

    This report analyzes a proposal that EPA sponsor a large-scale pilot plant to develop the Conoco (formerly Consol) Dolomite Hot Gas Clean-up system. The report includes a history of the prior development program, the technology involved comparisons with competitive technologies i...

  17. Iron Aluminide Hot Gas Filters

    SciTech Connect

    Hurley, J.; Brosious, S.; Johnson, M.

    1996-12-31

    Currently, high temperature filter systems are in the demonstration phase with the first commercial scale hot filter systems being installed on integrated gasification combined cycle (IGCC) and pressurized fluid bed combustion cycle (PBFC) systems (70 MW). They are dependent on the development of durable and economic high temperature filter systems. These filters are mostly ceramic tubes or candles. Ceramic filter durability has not been high. Failure is usually attributed to mechanical or thermal shock: they can also undergo significant changes due to service conditions. The overall objective of this project is to commercialize weldable, crack resistant filters which will provide several years service in advanced power processes. The specific objectives of this project are to develop corrosion resistant alloys and manufacturing processes to make Iron Aluminide filter media, and to use a ``short term`` exposure apparatus supported by other tests to identify the most promising candidate (alloy plus sintering cycle). The objectives of the next phases are to demonstrate long term corrosion stability for the best candidate followed by the production of fifty filters (optional).

  18. Method for hot gas conditioning

    DOEpatents

    Paisley, Mark A.

    1996-02-27

    A method for cracking and shifting a synthesis gas by the steps of providing a catalyst consisting essentially of alumina in a reaction zone; contacting the catalyst with a substantially oxygen free mixture of gases comprising water vapor and hydrocarbons having one or more carbon atoms, at a temperature between about 530.degree. C. (1000.degree. F.) to about 980.degree. C. (1800.degree. F.); and whereby the hydrocarbons are cracked to form hydrogen, carbon monoxide and/or carbon dioxide and the hydrogen content of the mixture increases with a corresponding decrease in carbon monoxide, and carbon formation is substantially eliminated.

  19. A dynamical model of supernova feedback: gas outflows from the interstellar medium

    NASA Astrophysics Data System (ADS)

    Lagos, Claudia del P.; Lacey, Cedric G.; Baugh, Carlton M.

    2013-12-01

    We present a dynamical model of supernova feedback which follows the evolution of pressurized bubbles driven by supernovae in a multiphase interstellar medium (ISM). The bubbles are followed until the point of break-out into the halo, starting from an initial adiabatic phase to a radiative phase. We show that a key property which sets the fate of bubbles in the ISM is the gas surface density, through the work done by the expansion of bubbles and its role in setting the gas scaleheight. The multiphase description of the ISM is essential, and neglecting it leads to order-of-magnitude differences in the predicted outflow rates. We compare our predicted mass loading and outflow velocities to observations of local and high-redshift galaxies and find good agreement over a wide range of stellar masses and velocities. With the aim of analysing the dependence of the mass loading of the outflow, β (i.e. the ratio between the outflow and star formation rates), on galaxy properties, we embed our model in the galaxy formation simulation, GALFORM, set in the Λ cold dark matter framework. We find that a dependence of β solely on the circular velocity, as is widely assumed in the literature, is actually a poor description of the outflow rate, as large variations with redshift and galaxy properties are obtained. Moreover, we find that below a circular velocity of ≈80 km s-1, the mass loading saturates. A more fundamental relation is that between β and the gas scaleheight of the disc, hg, and the gas fraction, fgas, as β ∝ h^{1.1}_g f^{0.4}_gas, or the gas surface density, Σg, and the gas fraction, as β ∝ Σ ^{-0.6}_g f^{0.8}_gas. We find that using the new mass loading model leads to a shallower faint-end slope in the predicted optical and near-IR galaxy luminosity functions.

  20. Control apparatus for hot gas engine

    DOEpatents

    Stotts, Robert E.

    1986-01-01

    A mean pressure power control system for a hot gas (Stirling) engine utilizing a plurality of supply tanks for storing a working gas at different pressures. During pump down operations gas is bled from the engine by a compressor having a plurality of independent pumping volumes. In one embodiment of the invention, a bypass control valve system allows one or more of the compressor volumes to be connected to the storage tanks. By selectively sequencing the bypass valves, a capacity range can be developed over the compressor that allows for lower engine idle pressures and more rapid pump down rates.

  1. Multiple volume compressor for hot gas engine

    DOEpatents

    Stotts, Robert E.

    1986-01-01

    A multiple volume compressor for use in a hot gas (Stirling) engine having a plurality of different volume chambers arranged to pump down the engine when decreased power is called for and return the working gas to a storage tank or reservoir. A valve actuated bypass loop is placed over each chamber which can be opened to return gas discharged from the chamber back to the inlet thereto. By selectively actuating the bypass valves, a number of different compressor capacities can be attained without changing compressor speed whereby the capacity of the compressor can be matched to the power available from the engine which is used to drive the compressor.

  2. Gas physical conditions and kinematics of the giant outflow Ou4

    NASA Astrophysics Data System (ADS)

    Corradi, Romano L. M.; Grosso, Nicolas; Acker, Agnès; Greimel, Robert; Guillout, Patrick

    2014-10-01

    Context. The recently discovered bipolar outflow Ou4 has a projected size of more than one degree in the plane of the sky. It is apparently centred on the young stellar cluster - whose most massive representative is the triple system HR 8119 - inside the H ii region Sh 2-129. The driving source, the nature, and the distance of Ou4 are not known. Aims: The basic properties of Ou4 and its environment are investigated to shed light on the origin of this remarkable outflow. Methods: Deep narrow-band imagery of the whole nebula at arcsecond resolution was obtained to study the details of its morphology. Long-slit spectroscopy of the bipolar lobe tips was secured to determine the gas ionisation mechanism, physical conditions, and line-of-sight velocities. An estimate of the proper motions at the tip of the south lobe using archival plate images was attempted. The existing multi-wavelength data for Sh 2-129 and HR 8119 were also comprehensively reviewed. Results: The observed morphology of Ou4, its emission-line spatial distribution, line flux ratios, and the kinematic modelling developed adopting a bow-shock parabolic geometry, illustrate the expansion of a shock-excited fast collimated outflow. The observed radial velocities of Ou4 and its reddening are consistent with those of Sh 2-129 and HR 8119. The improved determination of the distance to HR 8119 (composed of two B0 V and one B0.5 V stars) and Sh 2-129 is 712 pc. We identify in WISE images at 22 μm an emission bubble of 5' radius (1 pc at the distance above) emitted by hot (107 K) dust grains, located inside the central part of Ou4 and corresponding to several [O iii] emission features of Ou4. Conclusions: The apparent position of Ou4 and the properties studied in this work are consistent with the hypothesis that Ou4 is located inside the Sh 2-129 H ii region, suggesting that it was launched some 90 000 yr ago by HR 8119. The outflow total kinetic energy is estimated to be ≈4 × 1047 ergs. However, we cannot

  3. Hot gas filtration technical issues

    SciTech Connect

    Pontius, D.H.

    1995-11-01

    The primary objective of this research has been to provide an understanding of factors pertinent to the development of an effective filtration system for removing particles from high-temperature, high-pressure gas streams in advanced power generation systems under development by the Department of Energy. Information used to define the filtration system issues was compiled from the Morgantown Energy Technology Center (METC) Contractors Conferences, specific tasks assigned to Southern Research Institute, meetings with METC personnel and contractors, and other conferences and workshops organized by METC. Initial research and pilot scale installations have shown that there are some potential problem areas. Thick ash deposits have formed, bridging from passive surfaces to the filter material and between filter candles. A great number of ceramic filters have broken in various experimental and demonstration devices, especially during long-term testing. This paper reviews particulate characteristics (effects on filtration processes, conventional fly ash, gasifier char, PFBC ash, and detailed studies of PFBC ash) and ceramic filter materials (general issues, thermal stress, clay-bonded SiC filter materials, and monolithic ceramic materials).

  4. Hot-Gas Filter Ash Characterization Project

    SciTech Connect

    Swanson, M.L.; Hurley, J.P.; Dockter, B.A.; O`Keefe, C.A.

    1997-07-01

    Large-scale hot-gas filter testing over the past 10 years has revealed numerous cases of cake buildup on filter elements that has been difficult, if not impossible, to remove. At times, the cake can blind or bridge between candle filters, leading to filter failure. Physical factors, including particle-size distribution, particle shape, the aerodynamics of deposition, and system temperature, contribute to the difficulty in removing the cake, but chemical factors such as surface composition and gas-solid reactions also play roles in helping to bond the ash to the filters or to itself. This project is designed to perform the research necessary to determine the fuel-, sorbent-, and operations-related conditions that lead to blinding or bridging of hot-gas particle filters. The objectives of the project are threefold: (1) Determine the mechanisms by which a difficult-to-clean ash is formed and how it bridges hot-gas filters (2) Develop a method to determine the rate of bridging based on analyses of the feed coal and sorbent, filter properties, and system operating conditions and (3) Suggest and test ways to prevent filter bridging.

  5. Jet-driven outflows of ionized gas in the nearby radio galaxy 3C 293

    NASA Astrophysics Data System (ADS)

    Mahony, E. K.; Oonk, J. B. R.; Morganti, R.; Tadhunter, C.; Bessiere, P.; Short, P.; Emonts, B. H. C.; Oosterloo, T. A.

    2016-01-01

    Fast outflows of gas, driven by the interaction between the radio jets and interstellar medium (ISM) of the host galaxy, are being observed in an increasing number of galaxies. One such example is the nearby radio galaxy 3C 293. In this paper we present integral field unit observations taken with OASIS on the William Herschel Telescope, enabling us to map the spatial extent of the ionized gas outflows across the central regions of the galaxy. The jet-driven outflow in 3C 293 is detected along the inner radio lobes with a mass outflow rate ranging from ˜0.05 to 0.17 M⊙ yr-1 (in ionized gas) and corresponding kinetic power of ˜0.5-3.5 × 1040 erg s-1. Investigating the kinematics of the gas surrounding the radio jets (i.e. not directly associated with the outflow), we find linewidths broader than 300 km s-1 up to 5 kpc in the radial direction from the nucleus (corresponding to 3.5 kpc in the direction perpendicular to the radio axis at maximum extent). Along the axis of the radio jet linewidths >400 km s-1 are detected out to 7 kpc from the nucleus and linewidths of >500 km s-1 at a distance of 12 kpc from the nucleus, indicating that the disturbed kinematics clearly extend well beyond the high surface brightness radio structures of the jets. This is suggestive of the cocoon structure seen in simulations of jet-ISM interaction and implies that the radio jets are capable of disturbing the gas throughout the central regions of the host galaxy in all directions.

  6. HIGH-VELOCITY MOLECULAR OUTFLOW IN CO J = 7-6 EMISSION FROM THE ORION HOT CORE

    SciTech Connect

    Furuya, Ray S.; Shinnaga, Hiroko E-mail: shinnaga@submm.caltech.ed

    2009-10-01

    Using the Caltech Submillimeter Observatory 10.4 m telescope, we performed sensitive mapping observations of {sup 12}CO J = 7-6 emission at 807 GHz toward Orion IRc2. The image has an angular resolution of 10'', which is the highest angular resolution data toward the Orion Hot Core published for this transition. In addition, thanks to the on-the-fly mapping technique, the fidelity of the new image is rather high, particularly in comparison with previous images. We have succeeded in mapping the northwest-southeast high-velocity molecular outflow, whose terminal velocity is shifted by {approx}70-85 km s{sup -1} with respect to the systemic velocity of the cloud. This yields an extremely short dynamical time scale of {approx}900 years. The estimated outflow mass loss rate shows an extraordinarily high value, on the order of 10{sup -3} M {sub sun} yr{sup -1}. Assuming that the outflow is driven by Orion IRc2, our result agrees with the picture so far obtained for a 20 M {sub sun} (proto)star in the process of formation.

  7. Pilot gasification and hot gas cleanup operations

    SciTech Connect

    Rockey, J.M.; Galloway, E.; Thomson, T.A.; Rutten, J.; Lui, A.

    1995-12-31

    The Morgantown Energy Technology Center (METC) has an integrated gasification hot gas cleanup facility to develop gasification, hot particulate and desulfurization process performance data for IGCC systems. The objective of our program is to develop fluidized-bed process performance data for hot gas desulfurization and to further test promising sorbents from lab-scale screening studies at highpressure (300 psia), and temperatures (1,200{degrees}F) using coal-derived fuel gases from a fluid-bed gasifier. The 10-inch inside diameter (ID), nominal 80 lb/hr, air blown gasifier is capable of providing about 300 lb/hr of low BTU gas at 1,000{degrees}F and 425 psig to downstream cleanup devices. The system includes several particle removal stages, which provide the capability to tailor the particle loading to the cleanup section. The gas pressure is reduced to approximately 300 psia and filtered by a candle filter vessel containing up to four filter cartridges. For batch-mode desulfurization test operations, the filtered coal gas is fed to a 6-inch ID, fluid-bed reactor that is preloaded with desulfurization sorbent. Over 400 hours of gasifier operation was logged in 1993 including 384 hours of integration with the cleanup rig. System baseline studies without desulfurization sorbent and repeatability checks with zinc ferrite sorbent were conducted before testing with the then most advanced zinc titanate sorbents, ZT-002 and ZR-005. In addition to the desulfurization testing, candle filters were tested for the duration of the 384 hours of integrated operation. One filter was taken out of service after 254 hours of filtering while another was left in service. At the conclusion of testing this year it is expected that 3 candles, one each with 254, 530, and 784 hours of filtering will be available for analysis for effects of the exposure to the coal gas environment.

  8. THE DIVERSE HOT GAS CONTENT AND DYNAMICS OF OPTICALLY SIMILAR LOW-MASS ELLIPTICAL GALAXIES

    SciTech Connect

    Bogdan, Akos; David, Laurence P.; Jones, Christine; Forman, William R.; Kraft, Ralph P.

    2012-10-10

    The presence of hot X-ray-emitting gas is ubiquitous in massive early-type galaxies. However, much less is known about the content and physical status of the hot X-ray gas in low-mass ellipticals. In the present paper, we study the X-ray gas content of four low-mass elliptical galaxies using archival Chandra X-ray observations. The sample galaxies, NGC 821, NGC 3379, NGC 4278, and NGC 4697, have approximately identical K-band luminosities, and hence stellar masses, yet their X-ray appearance is strikingly different. We conclude that the unresolved emission in NGC 821 and NGC 3379 is built up from a multitude of faint compact objects, such as coronally active binaries and cataclysmic variables. Despite the non-detection of X-ray gas, these galaxies may host low density, and hence low luminosity, X-ray gas components, which undergo an outflow driven by a Type Ia supernova (SN Ia). We detect hot X-ray gas with a temperature of kT {approx} 0.35 keV in NGC 4278, the component of which has a steeper surface brightness distribution than the stellar light. Within the central 50'' ({approx}3.9 kpc), the estimated gas mass is {approx}3 Multiplication-Sign 10{sup 7} M{sub Sun }, implying a gas mass fraction of {approx}0.06%. We demonstrate that the X-ray gas exhibits a bipolar morphology in the northeast-southwest direction, indicating that it may be outflowing from the galaxy. The mass and energy budget of the outflow can be maintained by evolved stars and SNe Ia, respectively. The X-ray gas in NGC 4697 has an average temperature of kT {approx} 0.3 keV and a significantly broader distribution than the stellar light. The total gas mass within 90'' ({approx}5.1 kpc) is {approx}2.1 Multiplication-Sign 10{sup 8} M{sub Sun }, hence the gas mass fraction is {approx}0.4%. Based on the distribution and physical parameters of the X-ray gas, we conclude that it is most likely in hydrostatic equilibrium, although a subsonic outflow may be present.

  9. The Diverse Hot Gas Content and Dynamics of Optically Similar Low-mass Elliptical Galaxies

    NASA Astrophysics Data System (ADS)

    Bogdán, Ákos; David, Laurence P.; Jones, Christine; Forman, William R.; Kraft, Ralph P.

    2012-10-01

    The presence of hot X-ray-emitting gas is ubiquitous in massive early-type galaxies. However, much less is known about the content and physical status of the hot X-ray gas in low-mass ellipticals. In the present paper, we study the X-ray gas content of four low-mass elliptical galaxies using archival Chandra X-ray observations. The sample galaxies, NGC 821, NGC 3379, NGC 4278, and NGC 4697, have approximately identical K-band luminosities, and hence stellar masses, yet their X-ray appearance is strikingly different. We conclude that the unresolved emission in NGC 821 and NGC 3379 is built up from a multitude of faint compact objects, such as coronally active binaries and cataclysmic variables. Despite the non-detection of X-ray gas, these galaxies may host low density, and hence low luminosity, X-ray gas components, which undergo an outflow driven by a Type Ia supernova (SN Ia). We detect hot X-ray gas with a temperature of kT ~ 0.35 keV in NGC 4278, the component of which has a steeper surface brightness distribution than the stellar light. Within the central 50'' (~3.9 kpc), the estimated gas mass is ~3 × 107 M ⊙, implying a gas mass fraction of ~0.06%. We demonstrate that the X-ray gas exhibits a bipolar morphology in the northeast-southwest direction, indicating that it may be outflowing from the galaxy. The mass and energy budget of the outflow can be maintained by evolved stars and SNe Ia, respectively. The X-ray gas in NGC 4697 has an average temperature of kT ~ 0.3 keV and a significantly broader distribution than the stellar light. The total gas mass within 90'' (~5.1 kpc) is ~2.1 × 108 M ⊙, hence the gas mass fraction is ~0.4%. Based on the distribution and physical parameters of the X-ray gas, we conclude that it is most likely in hydrostatic equilibrium, although a subsonic outflow may be present.

  10. The Milky Way's Hot Gas Kinematics: Signatures in Current and Future OVII Absorption Line Observations

    NASA Astrophysics Data System (ADS)

    Miller, Matthew J.; Hodges-Kluck, Edmund J.; Bregman, Joel N.

    2016-02-01

    Detections of z ≈ 0 oxygen absorption and emission lines indicate the Milky Way hosts a hot (˜ {10}6 K), low-density plasma extending ≳ 50 {{kpc}} into the Mily Way’s halo. Current X-ray telescopes cannot resolve the line profiles, but the variation of their strengths on the sky constrains the radial gas distribution. Interpreting the O vii Kα absorption line strengths has several complications, including optical depth and line of sight velocity effects. Here, we present model absorption line profiles accounting for both of these effects to show the lines can exhibit asymmetric structures and be broader than the intrinsic Doppler width. The line profiles encode the hot gas rotation curve, the net inflow or outflow of hot gas, and the hot gas angular momentum profile. We show how line of sight velocity effects impact the conversion between equivalent width and the column density, and provide modified curves of growth accounting for these effects. As an example, we analyze the LMC sight line pulsar dispersion measure and O vii equivalent width to show the average gas metallicity is ≳ 0.6{Z}⊙ and b ≳ 100 km s-1. Determining these properties offers valuable insights into the dynamical state of the Milky Way’s hot gas, and improves the line strength interpretation. We discuss future strategies to observe these effects with an instrument that has a spectral resolution of about 3000, a goal that is technically possible today.

  11. SIMPLE MODELS OF METAL-LINE ABSORPTION AND EMISSION FROM COOL GAS OUTFLOWS

    SciTech Connect

    Prochaska, J. Xavier; Rubin, Kate

    2011-06-10

    We analyze the absorption and emission-line profiles produced by a set of simple, cool gas wind models motivated by galactic-scale outflow observations. We implement Monte Carlo radiative transfer techniques that track the propagation of scattered and fluorescent photons to generate one-dimensional spectra and two-dimensional spectral images. We focus on the Mg II {lambda}{lambda}2796, 2803 doublet and Fe II UV1 multiplet at {lambda} {approx} 2600 A, but the results are applicable to other transitions that trace outflows (e.g., Na I, H I Ly{alpha}, Si II). By design, the resonance transitions show blueshifted absorption but one also predicts strong resonance and fine-structure line emission at roughly the systemic velocity. This line-emission 'fills in' the absorption, reducing the equivalent width by up to 50%, shifting the absorption-line centroid by tens of km s{sup -1}, and reducing the effective opacity near systemic. Analysis of cool gas outflows that ignores this line emission may incorrectly infer that the gas is partially covered, measure a significantly lower peak optical depth, and/or conclude that gas at systemic velocity is absent (e.g., an interstellar or slowly infalling component). Because the Fe II lines are connected by optically thin transitions to fine-structure levels, their profiles more closely reproduce the intrinsic opacity of the wind. Together these results naturally explain the absorption and emission-line characteristics observed for star-forming galaxies at z < 1. We also study a scenario promoted to describe the outflows of z {approx} 3 Lyman break galaxies and find profiles inconsistent with the observations due to scattered photon emission. Although line emission complicates the analysis of absorption-line profiles, the surface brightness profiles offer a unique means of assessing the morphology and size of galactic-scale winds. Furthermore, the kinematics and line ratios offer powerful diagnostics of outflows, motivating deep

  12. Simple Models of Metal-line Absorption and Emission from Cool Gas Outflows

    NASA Astrophysics Data System (ADS)

    Prochaska, J. Xavier; Kasen, Daniel; Rubin, Kate

    2011-06-01

    We analyze the absorption and emission-line profiles produced by a set of simple, cool gas wind models motivated by galactic-scale outflow observations. We implement Monte Carlo radiative transfer techniques that track the propagation of scattered and fluorescent photons to generate one-dimensional spectra and two-dimensional spectral images. We focus on the Mg II λλ2796, 2803 doublet and Fe II UV1 multiplet at λ ≈ 2600 Å, but the results are applicable to other transitions that trace outflows (e.g., Na I, H I Lyα, Si II). By design, the resonance transitions show blueshifted absorption but one also predicts strong resonance and fine-structure line emission at roughly the systemic velocity. This line-emission "fills in" the absorption, reducing the equivalent width by up to 50%, shifting the absorption-line centroid by tens of km s-1, and reducing the effective opacity near systemic. Analysis of cool gas outflows that ignores this line emission may incorrectly infer that the gas is partially covered, measure a significantly lower peak optical depth, and/or conclude that gas at systemic velocity is absent (e.g., an interstellar or slowly infalling component). Because the Fe II lines are connected by optically thin transitions to fine-structure levels, their profiles more closely reproduce the intrinsic opacity of the wind. Together these results naturally explain the absorption and emission-line characteristics observed for star-forming galaxies at z < 1. We also study a scenario promoted to describe the outflows of z ~ 3 Lyman break galaxies and find profiles inconsistent with the observations due to scattered photon emission. Although line emission complicates the analysis of absorption-line profiles, the surface brightness profiles offer a unique means of assessing the morphology and size of galactic-scale winds. Furthermore, the kinematics and line ratios offer powerful diagnostics of outflows, motivating deep, spatially extended spectroscopic

  13. Hot and turbulent gas in clusters

    NASA Astrophysics Data System (ADS)

    Schmidt, W.; Engels, J. F.; Niemeyer, J. C.; Almgren, A. S.

    2016-06-01

    The gas in galaxy clusters is heated by shock compression through accretion (outer shocks) and mergers (inner shocks). These processes additionally produce turbulence. To analyse the relation between the thermal and turbulent energies of the gas under the influence of non-adiabatic processes, we performed numerical simulations of cosmic structure formation in a box of 152 Mpc comoving size with radiative cooling, UV background, and a subgrid scale model for numerically unresolved turbulence. By smoothing the gas velocities with an adaptive Kalman filter, we are able to estimate bulk flows towards cluster cores. This enables us to infer the velocity dispersion associated with the turbulent fluctuation relative to the bulk flow. For haloes with masses above 1013 M⊙, we find that the turbulent velocity dispersions averaged over the warm-hot intergalactic medium (WHIM) and the intracluster medium (ICM) are approximately given by powers of the mean gas temperatures with exponents around 0.5, corresponding to a roughly linear relation between turbulent and thermal energies and transonic Mach numbers. However, turbulence is only weakly correlated with the halo mass. Since the power-law relation is stiffer for the WHIM, the turbulent Mach number tends to increase with the mean temperature of the WHIM. This can be attributed to enhanced turbulence production relative to dissipation in particularly hot and turbulent clusters.

  14. Hot Gas Desulfurization Using Transport Reactors

    SciTech Connect

    Moorehead, E.L.

    1996-12-31

    Sierra Pacific Power Company is building a 100 MW, IGCC power plant based on KRW fluid bed gasifier technology that utilizes transport reactors for hot gas desulfurization and sorbent regeneration. Use of a transport absorber avoids the need for pre-filtration of dust-laden gasifier effluent, while a transport regenerator allows for the use of 100% air without the need for heat exchange equipment. Selection of transport reactors for hot gas desulfurization using a proprietary sorbent, based on testing performed in a transport reactor test unit (TRTU) at the M. W. Kellogg Technology Development Center and in a fixed bed reactor at Morgantown Energy Technology Center (METC), is outlined. The results obtained in these two test facilities and reasons for selecting transport reactors for the IGCC power plant in preference to either fixed bed or fluidized bed reactors are discussed. This paper reviews the evolution of the hot gas desulfurization system designs and includes selected results on H{sub 2}S absorption and regeneration of sulfided sorbent over several absorption/regeneration cycles conducted in the TRTU and the METC fixed bed reactor. The original design for the Sierra Pacific Project was based on fixed bed reactors with zinc ferrite as the sorbent. Owing to the high steam requirements of this sorbent, zinc titanate was selected and tested in a fixed bed reactor and was found unacceptable due to loss of strength on cyclic absorption/regeneration operation. Another sorbent evaluated was Z-Sorb{reg_sign}, a proprietary sorbent developed by Phillips Petroleum Company, was found to have excellent sulfur capacity, structural strength and regenerability. Steam was found unsuitable as fixed bed regenerator diluent, this results in a requirement for a large amount of inert gas, whereas a transport regenerator requires no diluent. The final Sierra design features transport reactors for both desulfurization and regeneration steps using neat air. 3 refs., 3 figs., 2 tabs.

  15. METC CFD simulations of hot gas filtration

    SciTech Connect

    O`Brien, T.J.

    1995-06-01

    Computational Fluid Dynamic (CFD) simulations of the fluid/particle flow in several hot gas filtration vessels will be presented. These simulations have been useful in designing filtration vessels and in diagnosing problems with filter operation. The simulations were performed using the commercial code FLUENT and the METC-developed code MFIX. Simulations of the initial configuration of the Karhula facility indicated that the dirty gas flow over the filter assemblage was very non-uniform. The force of the dirty gas inlet flow was inducing a large circulation pattern that caused flow around the candles to be in opposite directions on opposite sides of the vessel. By introducing a system of baffles, a more uniform flow pattern was developed. This modification may have contributed to the success of the project. Several simulations of configurations proposed by Industrial Filter and Pump were performed, varying the position of the inlet. A detailed resolution of the geometry of the candles allowed determination of the flow between the individual candles. Recent simulations in support of the METC/CeraMem Cooperative Research and Development Agreement have analyzed the flow in the vessel during the cleaning back-pulse. Visualization of experiments at the CeraMem cold-flow facility provided confidence in the use of CFD. Extensive simulations were then performed to assist in the design of the hot test facility being built by Ahlstrom/Pyropower. These tests are intended to demonstrate the CeraMem technology.

  16. SSME hot gas manifold flow comparison test

    NASA Technical Reports Server (NTRS)

    Cox, G. B., Jr.; Dill, C. C.

    1988-01-01

    An account is given of the High Pressure Fuel Turbopump (HPFT) component of NASA's Alternate Turbopump Development effort, which is aimed at the proper aerodynamic integration of the current Phase II three-duct SSME Hot Gas Manifold (HGM) and the future 'Phase II-plus' two-duct HGM. Half-scale water flow tests of both HGM geometries were conducted to provide initial design data for the HPFT. The results reveal flowfield results and furnish insight into the performance differences between the two HGM flowpaths. Proper design of the HPFT can potentially secure significant flow improvements in either HGM configuration.

  17. A Versatile Rocket Engine Hot Gas Facility

    NASA Technical Reports Server (NTRS)

    Green, James M.

    1993-01-01

    The capabilities of a versatile rocket engine facility, located in the Rocket Laboratory at the NASA Lewis Research Center, are presented. The gaseous hydrogen/oxygen facility can be used for thermal shock and hot gas testing of materials and structures as well as rocket propulsion testing. Testing over a wide range of operating conditions in both fuel and oxygen rich regimes can be conducted, with cooled or uncooled test specimens. The size and location of the test cell provide the ability to conduct large amounts of testing in short time periods with rapid turnaround between programs.

  18. [PFBC Hot Gas Cleanup Test Program

    SciTech Connect

    Not Available

    1992-10-01

    Four hundred and fifty four clay bonded silicon carbide Schumacher Dia Schumalith candle filters were purchased for installation in the Westinghouse Advanced Particle Filtration (APF) system at the American Electric Power (AEP) plant in Brilliant, Ohio. A surveillance effort has been identified which will monitor candle filter performance and life during hot gas cleaning in AEP's pressurized fluidized-bed combustion system. A description of the candle surveillance program, strategy for candle filter location selection, as well as candle filter post-test characterization is provided in this memo. The period of effort for candle filter surveillance monitoring is planned through March 1994.

  19. Particulate hot gas stream cleanup technical issues

    SciTech Connect

    Pontius, D.H.; Snyder, T.R.

    1999-09-30

    The analyses of hot gas stream cleanup particulate samples and descriptions of filter performance studied under this contract were designed to address problems with filter operation that have been linked to characteristics of the collected particulate matter. One objective of this work was to generate an interactive, computerized data bank of the key physical and chemical characteristics of ash and char collected from operating advanced particle filters and to relate these characteristics to the operation and performance of these filters. The interactive data bank summarizes analyses of over 160 ash and char samples from fifteen pressurized fluidized-bed combustion and gasification facilities utilizing high-temperature, high pressure barrier filters.

  20. Gas Dynamics and Outflow in the Barred Starburst Galaxy NGC 1808 Revealed with ALMA

    NASA Astrophysics Data System (ADS)

    Salak, Dragan; Nakai, Naomasa; Hatakeyama, Takuya; Miyamoto, Yusuke

    2016-05-01

    NGC 1808 is a nearby barred starburst galaxy with an outflow from the nuclear region. To study the inflow and outflow processes related to star formation and dynamical evolution of the galaxy, we have carried out 12CO (J=1-0) mapping observations of the central r ∼ 4 kpc of NGC 1808 using the Atacama Large Millimeter/submillimeter Array. Four distinct components of molecular gas are revealed at high spatial resolution of 2″ (∼100 pc): (1) a compact (r < 200 pc) circumnuclear disk (CND), (2) r ∼ 500 pc ring, (3) gas-rich galactic bar, and (4) spiral arms. Basic geometric and kinematic parameters are derived for the central 1 kpc region using tilted-ring modeling. The derived rotation curve reveals multiple mass components that include (1) a stellar bulge, (2) a nuclear bar and molecular CND, and (3) an unresolved massive (∼107 M ⊙) core. Two systemic velocities, 998 km s‑1 for the CND and 964 km s‑1 for the 500 pc ring, are revealed, indicating a kinematic offset. The pattern speed of the primary bar, derived by using a cloud-orbit model, is 56 ± 11 km s‑1 kpc‑1. Noncircular motions are detected associated with a nuclear spiral pattern and outflow in the central 1 kpc region. The ratio of the mass outflow rate to the star formation rate is {\\dot{M}}{out}/{SFR}∼ 0.2 in the case of optically thin CO (1–0) emission in the outflow, suggesting low efficiency of star formation quenching.

  1. Hot-Gas Filter Ash Characterization Project

    SciTech Connect

    Dockter, B.A.; Hurley, J.P.; Watne, T.A.; Katrinak, K.A.; O`Keefe, C.A.

    1996-12-31

    Large-scale hot-gas testing over the past several years has revealed numerous cases of cake buildup on filter elements that have been difficult, if not impossible to remove. At times, the cake can bridge between candle filters, leading to high filter failure rates. Physical factors, including particle-size distribution, particle shape, the aerodynamics of deposition, and system temperature contribute to difficulty in removing the cake. It is speculated that chemical as well as physical effects are playing a role in leading the ash to bond to the filter or to itself. The Energy and Environmental research Center (EERC) at the University of North Dakota is working with Electric Power Research Institute (EPRI) and a consortium of companies in partnership with the US Department of Energy (DOE) to perform the research necessary to determine the factors that cause hot-gas cleanup filters to be blinded by ash or to develop deposits that can bridge the filters and cause them to fail. The objectives of this overall project are threefold: first, to determine the mechanisms by which difficult-to-clean ash is formed; second, to develop a method to determine the rate of blinding/bridging based on fuel and sorbent properties and operating conditions; finally, to provide suggestions fro ways to prevent filter blinding by the troublesome ash. The projects consists of four tasks: field sampling and archive sample analyses, laboratory-scale testing, bench-scale testing, and model and database development testing. This paper present preliminary data from Task 2 on determining the tensile strengths of coal ash particles at elevated temperatures and simulated combustor gas conditions.

  2. A census of gas outflows in type 2 active galactic nuclei

    SciTech Connect

    Bae, Hyun-Jin; Woo, Jong-Hak E-mail: woo@astro.snu.ac.kr

    2014-11-01

    We perform a census of ionized gas outflows using a sample of ∼23,000 type 2 active galactic nuclei (AGNs) out to z ∼ 0.1. By measuring the velocity offset of narrow emission lines, i.e., [O III] λ5007 and Hα, with respect to the systemic velocity measured from the stellar absorption lines, we find that 47% of AGNs display an [O III] line-of-sight velocity offset ≥ 20 km s{sup –1}. The fraction of the [O III] velocity offset in type 2 AGNs is comparable to that in type 1 AGNs after considering the projection effect. AGNs with a large [O III] velocity offset preferentially have a high Eddington ratio, implying that the detected velocity offsets are related to black hole activity. The distribution of the host galaxy inclination is clearly different between the AGNs with blueshifted [O III] and the AGNs with redshifted [O III], supporting the combined model of the biconical outflow and dust obscuration. In addition, for ∼3% of AGNs, [O III] and Hα show comparable large velocity offsets, indicating a more complex gas kinematics than decelerating outflows in a stratified narrow-line region.

  3. General Electric hot gas cleanup and regeneration

    SciTech Connect

    Gal, E.; Furman, A.H.; Ayala, R.

    1993-06-01

    GE Environmental Services, Inc. (GEESI) and its major subcontractors GE Corporate Research and Development (GE-CRD) and GE Power Generation (GEPG) have completed significant further pilot plant scale test operation of an integrated fixed bed gasification, hot gas cleanup and gas turbine simulation facility located at GE-CRD in Schenectady, NY. Progress during the past year has included first desulfurization and regeneration testing with zinc titanate, significant regeneration hardware and process modifications, continued test exposure of a full scale gas turbine fuel control valve, first long term integrated operation of the MS6000 based gas turbine simulator and off-line operation of a subscale, staged combustor system designed to minimize NO{sub x} production from fuel bound nitrogen. Long Duration Tests 3, 3AR1, 3AR2 and 3A were conducted with zinc titanate sorbent and demonstrated the continued ability of the absorber to reduce inlet H{sub 2}S levels of 3500 ppmv to less than 30 ppmv provided properly regenerated sorbent was returned to the absorber. Tests 3AR1 and 3AR2 were limited duration, off line regeneration tests, utilizing residual sulfided material from Test 3, to evaluate continuing regeneration hardware, instrumentation and process modification. Test 3A was a fully integrated 100 hour test incorporating final regenerator modifications and resulted in first fully controlled regeneration. Anthracite coal was utilized for Test 3A as a means of partial elimination of halogens in the fuel gas prior to inclusion of a specific halogen removal process step envisioned for Long Duration Test 4. Further test operation will revert to use of Illinois bituminous coal with up to 3.4 percent sulfur and 0.1 to 0.28 percent chloride content in order to fully evaluate high sulfur regeneration operation as well as halogen removal.

  4. Flowfield visualization for SSME hot gas manifold

    NASA Technical Reports Server (NTRS)

    Roger, Robert P.

    1988-01-01

    The objective of this research, as defined by NASA-Marshall Space Flight Center, was two-fold: (1) to numerically simulate viscous subsonic flow in a proposed elliptical two-duct version of the fuel side Hot Gas Manifold (HGM) for the Space Shuttle Main Engine (SSME), and (2) to provide analytical support for SSME related numerical computational experiments, being performed by the Computational Fluid Dynamics staff in the Aerophysics Division of the Structures and Dynamics Laboratory at NASA-MSFC. Numerical results of HGM were calculations to complement both water flow visualization experiments and air flow visualization experiments and air experiments in two-duct geometries performed at NASA-MSFC and Rocketdyne. In addition, code modification and improvement efforts were to strengthen the CFD capabilities of NASA-MSFC for producing reliable predictions of flow environments within the SSME.

  5. Hot gas path component cooling system

    DOEpatents

    Lacy, Benjamin Paul; Bunker, Ronald Scott; Itzel, Gary Michael

    2014-02-18

    A cooling system for a hot gas path component is disclosed. The cooling system may include a component layer and a cover layer. The component layer may include a first inner surface and a second outer surface. The second outer surface may define a plurality of channels. The component layer may further define a plurality of passages extending generally between the first inner surface and the second outer surface. Each of the plurality of channels may be fluidly connected to at least one of the plurality of passages. The cover layer may be situated adjacent the second outer surface of the component layer. The plurality of passages may be configured to flow a cooling medium to the plurality of channels and provide impingement cooling to the cover layer. The plurality of channels may be configured to flow cooling medium therethrough, cooling the cover layer.

  6. Process for making ceramic hot gas filter

    DOEpatents

    Connolly, Elizabeth Sokolinski; Forsythe, George Daniel; Domanski, Daniel Matthew; Chambers, Jeffrey Allen; Rajendran, Govindasamy Paramasivam

    2001-01-01

    A ceramic hot-gas candle filter having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during backpulse cleaning and is resistant to chemical degradation at high temperatures.

  7. Hot gas engine with dual crankshafts

    SciTech Connect

    McDougal, A.R.

    1981-03-01

    A hot gas engine, such as a Stirling engine is described which comprises a displacer portion and an expander portion with a heat exchanger connected between them. The expander portion has a piston which is operatively connected to and rotates an expander crankshaft. In like manner, the displacer portion is provided with a piston which is also operatively connected to and rotates with a separate displacer crankshafts. The two crankshafts are synchronized with respect to each other preferably by means of an idler gear. Banks of displacer pistons can also be provided for operation on a common displacer crankshaft and banks of cooperating expander pistons also can be provided for operation on a common expander crankshaft. Official Gazette of the U.S. Patent and Trademark Office

  8. Power control for hot gas engines

    NASA Technical Reports Server (NTRS)

    Macglashan, W. F. (Inventor)

    1980-01-01

    A hot gas engine in which the expander piston of the engine is connected to an expander crankshaft. A displacer piston of the engine is connected to a separate displacer crankshaft which may or may not be coaxial with the expander crankshaft. A phase angle control mechanism used as a power control for changing the phase angle between the expander and displacer crankshaft is located between the two crankshafts. The phase angle control mechanism comprises a differential type mechanism comprised of a pair of gears, as for example, bevel gears, one of which is connected to one end of the expander crankshaft and the other of which is connected to the opposite end of the displacer crankshaft. A mating bevel gear is disposed in meshing engagement with the first two level gears to provide a phase angle control between the two crankshafts. Other forms of differential mechanisms may be used including conventional spur gears connected in a differential type arrangement.

  9. Hot gas engine with dual crankshafts

    NASA Technical Reports Server (NTRS)

    Mcdougal, A. R. (Inventor)

    1981-01-01

    A hot gas engine, such as a Stirling engine is described which comprises a displacer portion and an expander portion with a heat exchanger connected between them. The expander portion has a piston which is operatively connected to and rotates an expander crankshaft. In like manner, the displacer portion is provided with a piston which is also operatively connected to and rotates with a separate displacer crankshafts. The two crankshafts are synchronized with respect to each other preferably by means of an idler gear. Banks of displacer pistons can also be provided for operation on a common displacer crankshaft and banks of cooperating expander pistons also can be provided for operation on a common expander crankshaft.

  10. Diffuse Hot Gas in M51

    NASA Astrophysics Data System (ADS)

    Schlegel, Eric

    2014-08-01

    X-ray observations of face-on spiral galaxies reveal diffuse emission across the face of nearby galaxies. Whether that emission represents hot gas or unresolved point sources remains to be determined. We present two examples of our pursuit of an answer. First, a Chandra observation of M51 reveals a difference in the soft X-ray emission of the arms. The fitted spectra exhibit similar temperatures for the model components, but different abundances, particularly for Mg. Second, we compare the X-ray emission of M51 with data at other wavelengths via 'pixel statistics'. We adaptively bin the X-ray image and apply the resulting mask to data at other wavelengths to search for pixel correlations. We report on our results and inferences to date.

  11. Particulate Hot Gas Stream Cleanup Technical Issues

    SciTech Connect

    Dorchak, T.P.; Pontiu, D.H.; Snyder, T.R.

    1996-12-31

    The nature of the collected ash has been identified as an issue creating barriers to the commercialization of advanced particle control technologies. Since most of the emphasis and extended operation of Hot Gas Stream Cleanup (HGCU) facilities have been with ceramic candle filters, problems with ash characteristics can be understood in terms of their effects on these control devices. This project is designed to identify the ways ash characteristics affect advanced particle control technologies, to construct and maintain a data base of HGCU ashes and their measured characteristics, and to relate these characteristics to the operation and performance of these facilities. The key characteristics of the collected ash are the morphology of the overall ash aggregate (porosity, geometry of the pores, specific surface area, etc.), and the cohesivity of the aggregate. Our data base currently comprises 242 ash samples from 12 combustion and gasification (HGCU) sources.

  12. Maximized thermal efficiency crank driven hot gas engine

    SciTech Connect

    Pinto, A.P.

    1987-06-30

    A method is described for converting heat to mechanical shaft work in a reciprocating piston crank driven by a hot gas engine. The engine consists of a pair of hot and cold cylinders connected together with leak sealed flow paths. The flow paths have included valves and regenerator, the method comprising: (a) drawing the working gas into the cold cylinder; (b) compressing the gas in the cold cylinder with simultaneous removal of heat to keep the compression isothermal; (c) trapping the working gas in the cold cylinder during the isothermal compression, so that no working gas may enter or leave the cold cylinder during the isothermal compression; (d) setting the crank angular relationship between the hot and cold cylinder pistons such that the hot cylinder piston leads the cold cylinder piston by an angle determining the compression ratio of the engine; (e) transferring the gas from the cold cylinder to the hot cylinder, with addition of heat from the regenerator; (f) expanding the gas in the hot cylinder with the simultaneous addition of heat to keep the expansion isothermal; (g) trapping the working gas in the hot cylinder during the isothermal expansion, so that no working gas may enter or leave the hot cylinder during the isothermal expansion; (h) expelling gas from the hot cylinder to the working gas supply source with deposition of heat in the regenerator for addition to the compressed working gas of the next cycle; (i) selecting the hot and cold cylinder volumes to be approximately in the same ratio as the absolute temperatures of their respective isothermal processes such that the working gas transfers between them are isobaric.

  13. Development of iron-aluminide hot-gas filters

    SciTech Connect

    Tortorelli, P.F.; Wright, I.G.; Judkins, R.R.

    1996-06-01

    Removal of particles from hot synthesis gas produced by coal gasification is vital to the success of these systems. In Integrated [Coal] Gasification Combined Cycle systems, the synthesis gas is the fuel for gas turbines. To avoid damage to turbine components, it is necessary that particles be removed from the fuel gas prior to combustion and introduction into the turbine. Reliability and durability of the hot-gas filtering devices used to remove the particles is, of course, of special importance. Hot-gas filter materials include both ceramics and metals. Numerous considerations must be made in selecting materials for these filters. Constituents in the hot gases may potentially degrade the properties and performance of the filters to the point that they are ineffective in removing the particles. Very significant efforts have been made by DOE and others to develop effective hot-particle filters and, although improvements have been made, alternative materials and structures are still needed.

  14. Do Radio Jets Contribute to Driving Ionized Gas Outflows in Moderate Luminosity Type 2 AGN?

    NASA Astrophysics Data System (ADS)

    Fowler, Julia; Sajina, Anna; Lacy, Mark

    2016-01-01

    This poster examines the role of AGN-driven feedback in low to intermediate power radio galaxies. We begin with [OIII] measurements of ionized gas outflows in 29 moderate AGN-luminosity z~0.3-0.7 dust-obscured Type 2 AGN. We aim to examine the relative role of the AGN itself, of star-formation and of nascent radio jets in driving these outflows. The strength of the AGN and star formation are based on the [OIII] luminosities, and the far-IR luminosities respectively. For the radio jets, we present multi-frequency radio (X, S, and L-bands) JVLA imaging of our sample, which allows us both to constrain the overall radio power, but also look for signatures of young radio sources, including Giga-hertz Peaked Spectrum (GPS) sources, as well as small-scale jets. While radio jet-driven outflows are well known for powerful radio-loud galaxies, this study allows us to constrain the degree to which this mechanism is significant at more modest radio luminosities of L5GHz~10^22-25 W/Hz.

  15. Hot-gas filter ash characterization

    SciTech Connect

    Hurley, J.P.; Strobel, T.M.; Dockter, B.A.

    1995-11-01

    One of the key difficulties in the development of advanced pressurized fluidized-bed combustion (PFBC) and integrated gasification combined-cycle (IGCC) systems is the need to remove particulates from the gas stream at high temperatures and pressures. Research has revealed numerous cases of ash cake buildup on filter elements that has been difficult to remove using on-line jet pulsing. The objectives of this research are to: (1) determine the mechanisms by which a difficult-to-clean ash is formed and how it blinds or bridges hot-gas filters; (2) develop a method to determine the rate of blinding or bridging based on analyses of the feed coal and sorbent and on the operating conditions; and (3) provide suggestions for ways to prevent filter blinding and bridging by the troublesome ash. Four tasks are being performed: Task 1--field sampling and archive sample analysis; Task 2--laboratory-scale testing; Task 3--bench-scale testing; and Task 4--computer modeling. Results are presented from the first two tasks.

  16. Westinghouse hot gas particle filter system

    SciTech Connect

    Lippert, T.E.; Bruck, G.J.; Newby, R.A.; Bachovchin, D.M.; Debski, V.L.; Morehead, H.T.

    1997-12-31

    Integrated Gasification Combined Cycles (IGCC) and Pressurized Circulating Fluidized Bed Cycles (PCFB) are being developed and demonstrated for commercial power generation applications. Hot gas particulate filters (HGPF) are key components for the successful implementation of IGCC and PCFB in power generation gas turbine cycles. The objective is to develop and qualify through analysis and testing a practical HGPF system that meets the performance and operational requirements of PCFB and IGCC systems. This paper reports on the status of Westinghouse`s HGPF commercialization programs including: A quick summary of past gasification based HGPF test programs; A summary of the integrated HGPF operation at the American Electric Power, Tidd Pressurized Fluidized Bed Combustion (PFBC) Demonstration Project with approximately 6000 hours of HGPF testing completed; A summary of approximately 3200 hours of HGPF testing at the Foster Wheeler (FW) 10 MW{sub e} facility located in Karhula, Finland; A summary of over 700 hours of HGPF operation at the FW 2 MW{sub e} topping PCFB facility located in Livingston, New Jersey; A summary of the design of the HGPFs for the DOE/Southern Company Services, Power System Development Facility (PSDF) located in Wilsonville, Alabama; A summary of the design of the commercial-scale HGPF system for the Sierra Pacific, Pinon Pine IGCC Project; A review of completed testing and a summary of planned testing of Westinghouse HGPFs in Biomass IGCC applications; and A brief summary of the HGPF systems for the City of Lakeland, McIntosh Unit 4 PCFB Demonstration Project.

  17. Cold-gas outflows in typical low-redshift galaxies are driven by star formation, not AGN

    NASA Astrophysics Data System (ADS)

    Sarzi, Marc; Kaviraj, Sugata; Nedelchev, Borislav; Tiffany, Joshua; Shabala, Stanislav S.; Deller, Adam T.; Middelberg, Enno

    2016-02-01

    Energetic feedback from active galactic nuclei (AGN) is an important ingredient for regulating the star formation history of galaxies in models of galaxy formation, which makes it important to study how AGN feedback actually occurs in practice. In order to catch AGNs in the act of quenching star formation, we have used the interstellar Na I λλ5890, 5895(NaD) absorption lines to look for cold-gas outflows in a sample of 456 nearby galaxies for which we could unambiguously ascertain the presence of radio-AGN activity, thanks to radio imaging at milli-arcsecond scales. While compact radio emission indicating a radio AGN was found in 103 galaxies (23 per cent of the sample), and 23 objects (5 per cent) exhibited NaD absorption-line kinematics suggestive of cold-gas outflows, not one object showed evidence of a radio AGN and of a cold-gas outflow simultaneously. Radio-AGN activity was found predominantly in early-type galaxies, while cold-gas outflows were mainly seen in spiral galaxies with central star formation or composite star formation/AGN activity. Optical AGNs also do not seem capable of driving galactic winds in our sample. Our work adds to a picture of the low-redshift Universe, where cold-gas outflows in massive galaxies are generally driven by star formation and where radio-AGN activity occurs most often in systems in which the gas reservoir has already been significantly depleted.

  18. Ionized gas outflow in the isolated S0 galaxy NGC 4460

    NASA Astrophysics Data System (ADS)

    Moiseev, Alexei; Karachentsev, Igor; Kaisin, Serafim

    2010-04-01

    We used integral-field and long-slit spectroscopy to study a bright extended nebulosity recently discovered in the isolated lenticular galaxy NGC 4460 during an Hα survey of nearby galaxies. An analysis of archival Sloan Digital Sky Survey, GALEX and Hubble Space Telescope images indicates that current star formation is entirely concentrated in the central kiloparsec of the galaxy disc. The observed ionized gas parameters (morphology, kinematics and ionization state) can be explained by a gas outflow above the plane of the galaxy, caused by star formation in the circumnuclear region. Galactic wind parameters in NGC 4460 (outflow velocity, total kinetic energy) are several times smaller, compared with the known galactic wind in NGC 253, which is explained by the substantially lower total star formation rate. We discuss the cause of the star formation processes in NGC 4460 and in two other known isolated lenticular (S0) and elliptical (E) galaxies of the Local Volume: NGC 404 and 855. We provide evidence suggesting that the feeding of isolated galaxies by intergalactic gas on a cosmological time-scale is a steady process without significant variations. Based on observations collected with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences, which is operated under the financial support of the Science Department of Russia (registration number 01-43). E-mail: moisav@gmail.com

  19. Particulate hot gas stream cleanup technical issues

    SciTech Connect

    1998-09-01

    This is the tenth in a series of quarterly reports describing the activities performed under Contract No. DE-AC21-94MC31160. Analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic bed filter elements. Task I is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters. Task 2 concerns testing and failure analysis of ceramic filter elements. Under Task I during the past quarter, analyses were performed on a particulate sample from the Transport Reactor Demonstration Unit (TRDU) located at the University of North Dakota Energy and Environmental Research Center. Analyses are in progress on ash samples from the Advanced Particulate Filter (APF) at the Pressurized Fluidized-Bed Combustor (PFBC) that was in operation at Tidd and ash samples from the Pressurized Circulating Fluid Bed (PCFB) system located at Karhula, Finland. A site visit was made to the Power Systems Development Facility (PSDF) to collect ash samples from the filter vessel and to document the condition of the filter vessel with still photographs and videotape. Particulate samples obtained during this visit are currently being analyzed for entry into the Hot Gas Cleanup (HGCU) data base. Preparations are being made for a review meeting on ash bridging to be held at Department of Energy Federal Energy Technology Center - Morgantown (DOE/FETC-MGN) in the near future. Most work on Task 2 was on hold pending receipt of additional funds; however, creep testing of Schumacher FT20 continued. The creep tests on Schumacher FT20 specimens just recently ended and data analysis and comparisons to other data are ongoing. A summary and analysis of these creep results will be sent out shortly. Creep

  20. Suppression of galactic outflows by cosmological infall and circumgalactic medium

    NASA Astrophysics Data System (ADS)

    Singh, Priyanka; Rana, Sandeep; Bagla, Jasjeet S.; Nath, Biman B.

    2016-06-01

    We investigate the relative importance of two galactic outflow suppression mechanisms: (a) cosmological infall of the intergalactic gas on to the galaxy, and (b) the existence of a hot circumgalactic medium (CGM). Considering only radial motion, the infall reduces the speed of outflowing gas and even halts the outflow, depending on the mass and redshift of the galaxy. For star-forming galaxies, there exists an upper mass limit beyond which outflows are suppressed by the gravitational field of the galaxy. We find that infall can reduce this upper mass limit approximately by a factor of 2 (independent of the redshift). Massive galaxies (≳1012 M⊙) host large reservoir of hot, diffuse CGM around the central part of the galaxy. The CGM acts as a barrier between the infalling and outflowing gas and provides an additional source of outflow suppression. We find that at low redshifts (z ≲ 3.5), the CGM is more effective than the infall in suppressing the outflows. Together, these two processes give a mass range in which galaxies are unable to have effective outflows. We also discuss the impact of outflow suppression on the enrichment history of the galaxy and its environment.

  1. Neutral gas outflows in nearby [U]LIRGs via optical NaD feature

    NASA Astrophysics Data System (ADS)

    Cazzoli, S.; Arribas, S.; Maiolino, R.; Colina, L.

    2016-05-01

    We studied the properties of the neutral gas in a sample of 38 local luminous and ultra luminous infrared galaxies ([U]LIRGs, 51 individual galaxies at z ≤ 0.09), which mainly covers the less explored LIRG luminosity range. This study is based on the analysis of the spatially integrated and spatially resolved spectra of the NaDλλ 5890, 5896 Å feature obtained with the integral field unit (IFU) of VIMOS at the Very Large Telescope. Analyzing spatially integrated spectra, we find that the contribution of the stars to the observed NaD equivalent width is small (<35%) for about half of the sample, and therefore this feature is dominated by inter stellar medium (ISM) absorption. After subtracting the stellar contribution, we find that the pure-ISM integrated spectra generally show blueshifted NaD profiles, indicating neutral gas outflow velocities, V, in the range 65-260 km s-1. Excluding the galaxies with powerful AGNs, V shows a dependency with the star formation rate (SFR) of the type V ∝ SFR0.15, which is in rather good agreement with previous results. The spatially resolved analysis could be performed for 40 galaxies, 22 of which have neutral gas velocity fields dominated by noncircular motions with signatures of cone-like winds. However, a large number of targets (11/40) show disk rotation signatures. Based on a simple model, we found that the wind masses are in the range 0.4-7.5 × 108 M⊙, reaching up to ~3% of the dynamical mass of the host. The mass rates are typically only ~0.2-0.4 times the corresponding global SFR indicating that, in general, the mass loss is too small to slow down the star formation significantly. In the majority of cases, the velocity of the outflowing gas is not sufficient to escape the host potential well and, therefore, most of the gas rains back into the galaxy disk. On average V/vesc is higher in less massive galaxies, confirming that the galaxy mass has a primary role in shaping the recycling of gas and metals. The

  2. Power control for hot gas engines

    SciTech Connect

    Frosch, R.A.; Macglashan, W.F.

    1980-10-21

    A hot gas engine is described in which the expander piston of the engine is connected to an expander crankshaft. A displacer piston of the engine is connected to a separate displacer crankshaft which may or may not be coaxial with the expander crankshaft. A phase angle control mechanism used as a power control for changing the phase angle between the expander and displacer crankshaft is located between the two crankshafts. The phase angle control mechanism comprises a differential-type mechanism comprised of a pair of gears, as for example, bevel gears, one of which is connected to one end of the expander crankshaft and the other of which is connected to the opposite end of the displacer crankshaft. A mating bevel gear is disposed in meshing engagement with the first two bevel gears to provide a phase-angle control between the two crankshafts. Other forms of differential mechanisms may be used including conventional spur gears connected in a differential type arrangement.

  3. PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES

    SciTech Connect

    1999-05-05

    This is the fourth annual report describing the activities performed under Task 1 of Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This work is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters and their components. This report summarizes characterizations of ash and char samples from pressurized fluidized-bed combustion and gasification facilities. Efforts are under way to develop a method for preserving fragile filter cakes formed on ceramic filter elements. The HGCU data base was formatted for Microsoft Access 97 ® . Plans for the remainder of the project include characterization of additional samples collected during site visits to the Department of Energy / Southern Company Services Power Systems Development Facility and completion and delivery of the HGCU data base.

  4. PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES

    SciTech Connect

    1998-11-30

    This is the fourth annual report describing the activities performed under Task 1 of Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This work is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters and their components. This report summarizes characterizations of ash and char samples from pressurized fluidized-bed combustion and gasification facilities. Efforts are under way to develop a method for preserving fragile filter cakes formed on ceramic filter elements. The HGCU data base was formatted for Microsoft Access 97 ® . Plans for the remainder of the project include characterization of additional samples collected during site visits to the Department of Energy / Southern Company Services Power Systems Development Facility and completion and delivery of the HGCU data base.

  5. PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES

    SciTech Connect

    1999-05-05

    This is the fourth annual report describing the activities performed under Task 1 of Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This work is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters and their components. This report summarizes characterizations of ash and char samples from pressurized fluidized-bed combustion and gasification facilities. Efforts are under way to develop a method for preserving fragile filter cakes formed on ceramic filter elements. The HGCU data base was formatted for Microsoft Access 97{reg_sign}. Plans for the remainder of the project include characterization of additional samples collected during site visits to the Department of Energy/Southern Company Services Power Systems Development Facility and completion and delivery of the HGCU data base.

  6. The molecular gas content of the Pipe Nebula. I. Direct evidence of outflow-generated turbulence in B59?

    NASA Astrophysics Data System (ADS)

    Duarte-Cabral, A.; Chrysostomou, A.; Peretto, N.; Fuller, G. A.; Matthews, B.; Schieven, G.; Davis, G. R.

    2012-07-01

    Context. Star forming regions may share many characteristics, but the specific interplay between gravity, magnetic fields, large-scale dynamics, and protostellar feedback will have an impact on the star formation history of each region. The importance of feedback from outflows is a particular subject to debate, as we are yet to understand the details of their impact on clouds and star formation. Aims: The Pipe Nebula is a nearby molecular cloud hosting the B59 region as its only active star-forming clump. This paper focuses on the global dynamics of B59, its temperature structure, and its outflowing gas, with the goal of revealing the local and global impact of the protostellar outflows. Methods: Using HARP at the James Clerk Maxwell Telescope, we have mapped the B59 region in the J = 3 → 2 transition of 12CO to study the kinematics and energetics of the outflows, and the same transitions of 13CO and C18O to study the overall dynamics of the ambient cloud, the physical properties of the gas, and the hierarchical structure of the region. Results: The B59 region has a total of ~30 M⊙ of cold and quiescent material, mostly gravitationally bound, with narrow line widths throughout. Such low levels of turbulence in the non-star-forming regions within B59 are indicative of the intrinsic initial conditions of the cloud. On the other hand, close to the protostars the impact of the outflows is observed as a localised increase of both C18O line widths from ~0.3 km s-1 to ~1 km s-1, and 13CO excitation temperatures by ~2-3 K. The impact of the outflows is also evident in the low column density material which shows signs of being shaped by the outflow bow shocks as they pierce their way out of the cloud. Much of this structure is readily apparent in a dendrogram analysis of the cloud and demonstrates that when decomposing clouds using such techniques a careful interpretation of the results is needed. Conclusions: The low mass of B59 together with its intrinsically

  7. Particulate Hot Gas Stream Cleanup Technical Issues

    SciTech Connect

    Potius, D.; Snyder, T.

    1997-07-01

    The characteristics of entrained particles generated by advanced coal conversion technologies and the harsh flue gas environments from which these particles must be removed challenge current ceramic barrier filtration systems. Measurements have shown that the size distribution, morphology, and chemical composition of particles generated by pressurized fluidized-bed combustion (PFBC) and gasification processes differ significantly from the corresponding characteristics of conventional pulverized-coal ash particles. The entrained particulate matter from these advanced conversion technologies often comprise fine size distributions, irregular particle morphologies, high specific surface areas, and significant proportions of added sorbent material. These characteristics can create high ash cohesivity and high pressure losses through the filter cakes. In addition, the distributions of chemical constituents among the collected particles provide local, highly concentrated chemical species that promote reactions between adjacent particles that ultimately cause strong, nodular deposits to form in the filter vessel. These deposits can lead directly to bridging and filter element failure. This project is designed to address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic filter elements. The activities conducted under Task 1, Assessment of Ash Characteristics, are discussed in this paper. Activities conducted under Task 2, Testing and Failure Analysis of Ceramic Filters, are discussed in a separate paper included in the proceedings of the Advanced Coal-Based Power and Environmental Systems `97 Conference. The specific objectives of Task I include the generation of a data base of the key characteristics of Hot Gas Stream Cleanup (HGCU) ashes collected from operating advanced particle filters (APFS) and the identification of relationships between HGCU ash properties and the operation and

  8. Hydrocarbon anomaly in soil gas as near-surface expressions of upflows and outflows in geothermal systems

    SciTech Connect

    Ong, H.L.; Higashihara, M.; Klusman, R.W.; Voorhees, K.J.; Pudjianto, R.; Ong, J

    1996-01-24

    A variety of hydrocarbons, C1 - C12, have been found in volcanic gases (fumarolic) and in geothermal waters and gases. The hydrocarbons are thought to have come from products of pyrolysis of kerogen in sedimentary rocks or they could be fed into the geothermal system by the recharging waters which may contain dissolved hydrocarbons or hydrocarbons extracted by the waters from the rocks. In the hot geothermal zone, 300°+ C, many of these hydrocarbons are in their critical state. It is thought that they move upwards due to buoyancy and flux up with the upflowing geothermal fluids in the upflow zones together with the magmatic gases. Permeability which could be provided by faults, fissures, mini and micro fractures are thought to provide pathways for the upward flux. A sensitive technique (Petrex) utilizing passive integrative adsorption of the hydrocarbons in soil gas on activated charcoal followed by desorption and analysis of the hydrocarbons by direct introduction mass spectrometry allows mapping of the anomalous areas. Surveys for geothermal resources conducted in Japan and in Indonesia show that the hydrocarbon anomaly occur over known fields and over areas strongly suspected of geothermal potential. The hydrocarbons found and identified were n-paraffins (C7-C9) and aromatics (C7-C8). Detection of permeable, i.e. active or open faults, parts of older faults which have been reactivated, e.g. by younger intersecting faults, and the area surrounding these faulted and permeable region is possible. The mechanism leading to the appearance of the hydrocarbon in the soil gas over upflow zones of the geothermal reservoir is proposed. The paraffins seems to be better pathfinders for the location of upflows than the aromatics. However the aromatics may, under certain circumstances, give better indications of the direction of the outflow of the geothermal system. It is thought that an upflow zone can be

  9. Initiation of Martian Outflow Channels: Related to the Dissociation of Gas Hydrate?

    NASA Technical Reports Server (NTRS)

    Max, Michael D.; Clifford, Stephen M.

    2001-01-01

    We propose that the disruption of subpermafrost aquifers on Mars by the thermal- or pressure-induced dissociation of methane hydrate may have been a frequent trigger for initiating outflow channel activity. This possibility is raised by recent work that suggests that significant amounts of methane and gas hydrate may have been produced within and beneath the planet's cryosphere. On Earth, the build-up of overpressured water and gas by the decomposition of hydrate deposits has been implicated in the formation of large blowout features on the ocean floor. These features display a remarkable resemblance (in both morphology and scale) to the chaotic terrain found at the source of many Martian channels. The destabilization of hydrate can generate pressures sufficient to disrupt aquifers confined by up to 5 kilometers of frozen ground, while smaller discharges may result from the water produced by the decomposition of near-surface hydrate alone.

  10. Hot gas and magnetic arms of NGC 6946: Indications for reconnection heating?

    NASA Astrophysics Data System (ADS)

    Weżgowiec, M.; Ehle, M.; Beck, R.

    2016-01-01

    Context. The grand-design face-on spiral galaxy NGC 6946 is remarkable because of its high star formation activity, the massive northern spiral arm, and the magnetic arms, which are observed in polarized radio synchrotron emission and are located between the optical arms and possibly are magnetic reconnection regions. Aims: We used electron densities and temperatures in star-forming (active) and less active regions and compared them to findings from the analysis of the radio data to study the energy budget of NGC 6946. The hot gas above the magnetic arms between the optical arms might suggest gas heating by reconnection. We also study the population of point sources in NGC 6946, including the origin of the puzzling ultra-luminous emission complex MF16. Methods: X-ray observations of NGC 6946 performed with XMM-Newton were used to study the emission from X-ray point sources and diffuse hot gas, including the magnetic arms and the halo. Spectral fitting of the diffuse X-ray emission allowed us to derive temperatures of the hot gas. With assumptions about the emission volume, this allowed us to estimate gas densities, masses, and cooling times. Results: To explain the X-ray emission from the spiral arms of NGC 6946 two-temperature plasma models are needed to account for the disk and halo emission. The interarm regions show only one thermal component. We observe that the temperature of the hot gas in and above the magnetic arm regions increases slightly when compared to the average temperatures in the areas in and above the spiral arms. For the southwestern part of the disk, which is depolarized in the radio range by Faraday rotation, we find more efficient mixing of disk and halo gas. Conclusions: We propose magnetic reconnection in the magnetic arm regions of NGC 6946 as the possible cause of the additional heating of the gas and ordering of the magnetic fields. In the southwestern part of the galactic disk we observed indications of a possible faster outflow of the

  11. Particulate hot gas stream cleanup technical issues

    SciTech Connect

    1998-09-01

    This is the thirteenth quarterly report describing the activities performed under Contract No. DE-AC21-94MC31160. The analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. Task 1 is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters and their components. APF operations have also been limited by the strength and durability of the ceramic materials that have served as barrier filters for the capture of entrained HGCU ashes. Task 2 concerns testing and failure analyses of ceramic filter elements currently used in operating APFs and the characterization and evaluation of new ceramic materials. Task I research activities during the past quarter included characterizations of additional ash samples from Pressurized Fluidized-Bed Combustion (PFBC) facilities to the HGCU data base. Task I plans for the next quarter include characterization of samples collected during a site visit on January 20 to the Department of Energy / Southern Company Services Power Systems Development Facility (PSDF). Further work on the HGCU data base is also planned. Task 2 work during the past quarter included creep testing of a Coors P- I OOA- I specimen machined from Candle FC- 007 after 1166 hours in-service at the Karhula Pressurized Circulating Fluid Bed (PCFB) facility. Samples are currently in preparation for microstructural evaluations of Coors P-IOOA-I.Sixteen cordierite rings manufactured by Specific Surfaces were received for testing. Three of the specimens were exposed to the PFBC environment at the PSDF. These specimens are currently being machined for testing.

  12. Modeling Hot Gas Flow in the Low-luminosity Active Galactic Nucleus of NGC 3115

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Roman V.; Wong, Ka-Wah; Irwin, Jimmy A.; Reynolds, Christopher S.

    2014-02-01

    Based on the dynamical black hole (BH) mass estimates, NGC 3115 hosts the closest billion solar mass BH. Deep studies of the center revealed a very underluminous active galactic nucleus (AGN) immersed in an old massive nuclear star cluster. Recent 1 Ms Chandra X-ray visionary project observations of the NGC 3115 nucleus resolved hot tenuous gas, which fuels the AGN. In this paper we connect the processes in the nuclear star cluster with the feeding of the supermassive BH. We model the hot gas flow sustained by the injection of matter and energy from the stars and supernova explosions. We incorporate electron heat conduction as the small-scale feedback mechanism, the gravitational pull of the stellar mass, cooling, and Coulomb collisions. Fitting simulated X-ray emission to the spatially and spectrally resolved observed data, we find the best-fitting solutions with χ2/dof = 1.00 for dof = 236 both with and without conduction. The radial modeling favors a low BH mass <1.3 × 109 M ⊙. The best-fitting supernova rate and the best-fitting mass injection rate are consistent with their expected values. The stagnation point is at r st <~ 1'', so that most of the gas, including the gas at a Bondi radius rB = 2''-4'', outflows from the region. We put an upper limit on the accretion rate at 2 × 10-3 M ⊙ yr-1. We find a shallow density profile nvpropr -β with β ≈ 1 over a large dynamic range. This density profile is determined in the feeding region 0.''5-10'' as an interplay of four processes and effects: (1) the radius-dependent mass injection, (2) the effect of the galactic gravitational potential, (3) the accretion flow onset at r <~ 1'', and (4) the outflow at r >~ 1''. The gas temperature is close to the virial temperature Tv at any radius.

  13. Thick discs, and an outflow, of dense gas in the nuclei of nearby Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Lin, Ming-Yi; Davies, R. I.; Burtscher, L.; Contursi, A.; Genzel, R.; González-Alfonso, E.; Graciá-Carpio, J.; Janssen, A.; Lutz, D.; Orban de Xivry, G.; Rosario, D.; Schnorr-Müller, A.; Sternberg, A.; Sturm, E.; Tacconi, L.

    2016-05-01

    We discuss the dense molecular gas in central regions of nearby Seyfert galaxies, and report new arcsec resolution observations of HCN (1-0) and HCO+ (1-0) for three objects. In NGC 3079, the lines show complex profiles as a result of self-absorption and saturated continuum absorption. H13CN reveals the continuum absorption profile, with a peak close to the galaxy's systemic velocity that traces disc rotation, and a second feature with a blue wing extending to -350 km s-1 that most likely traces a nuclear outflow. The morphological and spectral properties of the emission lines allow us to constrain the dense gas dynamics. We combine our kinematic analysis for these three objects, as well as another with archival data, with a previous comparable analysis of four other objects, to create a sample of eight Seyferts. In seven of these, the emission line kinematics imply thick disc structures on radial scales of ˜100 pc, suggesting such structures are a common occurrence. We find a relation between the circum-nuclear LHCN and Mdyn that can be explained by a gas fraction of 10 per cent and a conversion factor αHCN ˜ 10 between gas mass and HCN luminosity. Finally, adopting a different perspective to probe the physical properties of the gas around active galactic nuclei, we report on an analysis of molecular line ratios which indicates that the clouds in this region are not self-gravitating.

  14. Gas outflow and dust transport of comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Lai, Ian-Lin; Su, Cheng-Chin; Ip, Wing-Huen; Lee, Jui-Chi; Lin, Zhong-Yi; Wu, Jong-Shinn

    2016-04-01

    Because of the diurnal thermal cycle and the irregular shape of the nucleus, gas outflow of comet 67P/Churyumov-Gerasimenko could be highly anisotropic as possibly indicated by the colliminated dust jet structures on the sunlit side. Based on the preliminary study of the outgassing effect from the early phase of the Rosetta mission, a simple model of surface sublimation can be constructed by taking into account the dependence on the solar insolation. By implementing the time variability of the global gas production rate, a sequence of gas coma models can be generated at different epochs before and after perihelion by using an advanced DSMC code [1, 2] to calculate the gas flow near the cometary nucleus. At selected time intervals, we will also investigate the size change of the cometary ionosphere as the nucleus rotates as well as the ejection of dust particles dragged by the gas flow into bounded and unbounded trajectories. Reference: 1. Wu, J.-S., Tseng, K.-C. and Wu, F.-Y., "Parallel three-dimensional DSMC method using mesh refinement and variable time-step scheme", Comput. Phys. Comm., 162, pp. 166-187, 2004. 2. Su, C.-C., Tseng, K.-C., Cave, H.M., Wu, J.-S., Lian, Y.-Y., Kuo, T.-C. and Jermy, M.C., "Implementation of a Transient Adaptive Sub-Cell Module for the Parallel DSMC Code Using Unstructured Grids," Computers & Fluids, Vol. 39, pp. 1136-1145, 2010.

  15. Hot Electromagnetic Outflows. III. Displaced Fireball in a Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Thompson, Christopher; Gill, Ramandeep

    2014-08-01

    The evolution of a dilute electron-positron fireball is calculated in the regime of strong magnetization and high compactness (l ~ 103-108). Heating is applied at a low effective temperature (<25 keV), appropriate to breakout from a confining medium, so that relaxation to a blackbody is inhibited by pair annihilation. The diffusion equation for Compton scattering by thermal pairs is coupled to a trans-relativistic cyclo-synchrotron source. We find that the photon spectrum develops a quasi-thermal peak at energy ~0.1 mec 2 in the comoving frame, with a power-law slope below it that is characteristic of gamma-ray bursts (GRBs; F ω ~ const). The formation of a thermal high-energy spectrum is checked using the full kinetic equations. Calculations for a baryon-dominated photosphere reveal a lower spectral peak energy, and a harder low-energy spectrum, unless ion rest mass carries <~ 10-5 of the energy flux. We infer that (1) the GRB spectrum is inconsistent with the neutron-rich wind emitted by a young magnetar or neutron torus, and points to an event horizon in the engine; (2) neutrons play a negligible role in prompt gamma-ray emission; (3) the relation between observed peak frequency and burst energy is bounded below by the observed Amati relation if the Lorentz factor ~(opening angle)-1 at breakout, and the jet is surrounded by a broader sheath that interacts with a collapsing stellar core; (4) X-ray flashes are consistent with magnetized jets with ion-dominated photospheres; (5) high-frequency Alfvén waves may become charge starved in the dilute pair gas; (6) limitations on magnetic reconnection from plasma collisionality have been overestimated.

  16. Hot electromagnetic outflows. III. Displaced fireball in a strong magnetic field

    SciTech Connect

    Thompson, Christopher; Gill, Ramandeep

    2014-08-10

    The evolution of a dilute electron-positron fireball is calculated in the regime of strong magnetization and high compactness (ℓ ∼ 10{sup 3}-10{sup 8}). Heating is applied at a low effective temperature (<25 keV), appropriate to breakout from a confining medium, so that relaxation to a blackbody is inhibited by pair annihilation. The diffusion equation for Compton scattering by thermal pairs is coupled to a trans-relativistic cyclo-synchrotron source. We find that the photon spectrum develops a quasi-thermal peak at energy ∼0.1 m{sub e}c {sup 2} in the comoving frame, with a power-law slope below it that is characteristic of gamma-ray bursts (GRBs; F{sub ω} ∼ const). The formation of a thermal high-energy spectrum is checked using the full kinetic equations. Calculations for a baryon-dominated photosphere reveal a lower spectral peak energy, and a harder low-energy spectrum, unless ion rest mass carries ≲ 10{sup –5} of the energy flux. We infer that (1) the GRB spectrum is inconsistent with the neutron-rich wind emitted by a young magnetar or neutron torus, and points to an event horizon in the engine; (2) neutrons play a negligible role in prompt gamma-ray emission; (3) the relation between observed peak frequency and burst energy is bounded below by the observed Amati relation if the Lorentz factor ∼(opening angle){sup –1} at breakout, and the jet is surrounded by a broader sheath that interacts with a collapsing stellar core; (4) X-ray flashes are consistent with magnetized jets with ion-dominated photospheres; (5) high-frequency Alfvén waves may become charge starved in the dilute pair gas; (6) limitations on magnetic reconnection from plasma collisionality have been overestimated.

  17. STRONG MOLECULAR HYDROGEN EMISSION AND KINEMATICS OF THE MULTIPHASE GAS IN RADIO GALAXIES WITH FAST JET-DRIVEN OUTFLOWS

    SciTech Connect

    Guillard, P.; Ogle, P. M.; Emonts, B. H. C.; Appleton, P. N.; Morganti, R.; Oosterloo, T.; Tadhunter, C.; Evans, D. A.; Evans, A. S.

    2012-03-10

    Observations of ionized and neutral gas outflows in radio galaxies (RGs) suggest that active galactic nucleus (AGN) radio jet feedback has a galaxy-scale impact on the host interstellar medium, but it is still unclear how the molecular gas is affected. Thus, it is crucial to determine the physical conditions of the molecular gas in powerful RGs to understand how radio sources may regulate the star formation in their host galaxies. We present deep Spitzer Infrared Spectrograph (IRS) high-resolution spectroscopy of eight nearby RGs that show fast H I outflows. Strikingly, all of these H I-outflow RGs have bright H{sub 2} mid-IR lines that cannot be accounted for by UV or X-ray heating. This strongly suggests that the radio jet, which drives the H I outflow, is also responsible for the shock excitation of the warm H{sub 2} gas. In addition, the warm H{sub 2} gas does not share the kinematics of the ionized/neutral gas. The mid-IR-ionized gas lines (with FWHM up to 1250 km s{sup -1} for [Ne II] 12.8 {mu}m) are systematically broader than the H{sub 2} lines, which are resolved by the IRS in Almost-Equal-To 60% of the detected lines (with FWHM up to 900 km s{sup -1}). In five sources, 3C 236, 3C 293, 3C 459, 4C 12.50, and PKS 1549-79, the [Ne II] 12.8 {mu}m line, and to a lesser extent the [Ne III] 15.5 {mu}m and [Ne V] 14.3 {mu}m lines, clearly exhibits blueshifted wings (up to -900 km s{sup -1} with respect to the systemic velocity) that match well the kinematics of the outflowing H I or ionized gas. The H{sub 2} lines do not show these broad wings, except tentative detections in 4C 12.50, 3C 459, and PKS 1549-79. This shows that, contrary to the H I gas, the H{sub 2} gas is inefficiently coupled to the AGN jet-driven outflow of ionized gas. While the dissipation of a small fraction (<10%) of the jet kinetic power can explain the turbulent heating of the molecular gas, our data show that the bulk of the warm molecular gas is not expelled from these galaxies.

  18. Outflowing Diffuse Gas in the Active Galactic Nucleus of NGC 1068

    NASA Astrophysics Data System (ADS)

    Geballe, T. R.; Mason, R. E.; Oka, T.

    2015-10-01

    Spectra of the archetypal Type II Seyfert galaxy NGC 1068 in a narrow wavelength interval near 3.7 μm have revealed a weak absorption feature due to two lines of the molecular ion {{{H}}}3+. The observed wavelength of the feature corresponds to a velocity of -70 km s-1 relative to the systemic velocity of the galaxy, implying an outward flow from the nucleus along the line of sight. The absorption by H{}3+ along with the previously known broad hydrocarbon absorption at 3.4μm are probably formed in diffuse gas that is in close proximity to the continuum source, i.e., within a few tens of parsecs of the central engine. Based on that conclusion and the measured H{}3+ absorption velocity and with the assumption of a spherically symmetric wind we estimate a rate of mass outflow from the active galactic nucleus of ˜1 M⊙ yr-1.

  19. Particulate Hot Gas Stream Cleanup Technical Issues

    SciTech Connect

    None, None

    1998-08-31

    This is the fifteenth quarterly report describing the activities performed under Contract No. DE-AC21-94MC31160. The analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. Task 1 is designed to generate a data bank of the key characteristics of ashes collected from operating advanced particle filters (APFs) and to relate these ash properties to the operation and performance of these filters and their components. APF operations have also been limited by the strength and durability of the ceramic materials that have served as barrier filters for the capture of entrained HGCU ashes. Task 2 concerns testing and failure analyses of ceramic filter elements currently used in operating APFs and the characterization and evaluation of new ceramic materials. Task 1 research activities during the past quarter included characterizations of samples collected during a site visit on May 18 to the Department of Energy / Southern Company Services Power Systems Development Facility (PSDF) and a particulate sample collected in the Westinghouse filter at Sierra Pacific Power Company's Piñon Pine Power Project. Analysis of this Piñon Pine sample is ongoing: however, this report contains the results of analyses completed to date. Significant accomplishments were achieved on the HGCU data bank during this reporting quarter. The data bank was prepared for presentation at the Advanced Coal-Based Power and Environmental Systems 98 Conference scheduled for July, 1998. Task 2 work during the past quarter consisted of testing two Dupont PRD-66C candle filters, one McDermott ceramic composite candle filter, one Blasch 4-270 candle filter, and one Specific Surface cordierite candle filter. Tensile and thermal expansion testing is complete and the rest of the testing is in progress. Also, some 20-inch long Dupont

  20. Particulate hot gas stream cleanup technical issues

    SciTech Connect

    1998-09-01

    This is the eleventh in a series of quarterly reports describing the activities performed under Contract No. DE-AC21-94MC31160. Analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic bed filter elements. Task 1 is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters. Task 2 concerns testing and failure analysis of ceramic filter elements. Under Task 1 during the past quarter, analyses were completed on samples obtained during a site visit to the Power Systems Development Facility (PSDF). Analyses are in progress on ash samples from the Advanced Particulate Filter (APF) at the Pressurized Fluidized-Bed Combustor (PFBC) that was in operation at Tidd and ash samples from the Pressurized Circulating Fluid Bed (PCFB) system located at Karhula, Finland. An additional analysis was performed on a particulate sample from the Transport Reactor Demonstration Unit (TRDU) located at the University of North Dakota Energy and Environmental Research Center. A manuscript and poster were prepared for presentation at the Advanced Coal-Based Power and Environmental Systems `97 Conference scheduled for July 22 - 24, 1997. A summary of recent project work covering the mechanisms responsible for ash deposit consolidation and ash bridging in APF`s collecting PFB ash was prepared and presented at FETC-MGN in early July. The material presented at that meeting is included in the manuscript prepared for the Contractor`s Conference and also in this report. Task 2 work during the past quarter included mechanical testing and microstructural examination of Schumacher FT20 and Pall 326 as- manufactured, after 540 hr in service at Karhula, and after 1166 hr in service at

  1. Power control system for a hot gas engine

    DOEpatents

    Berntell, John O.

    1986-01-01

    A power control system for a hot gas engine of the type in which the power output is controlled by varying the mean pressure of the working gas charge in the engine has according to the present invention been provided with two working gas reservoirs at substantially different pressure levels. At working gas pressures below the lower of said levels the high pressure gas reservoir is cut out from the control system, and at higher pressures the low pressure gas reservoir is cut out from the system, thereby enabling a single one-stage compressor to handle gas within a wide pressure range at a low compression ratio.

  2. The multi-phase winds of Markarian 231: from the hot, nuclear, ultra-fast wind to the galaxy-scale, molecular outflow

    NASA Astrophysics Data System (ADS)

    Feruglio, C.; Fiore, F.; Carniani, S.; Piconcelli, E.; Zappacosta, L.; Bongiorno, A.; Cicone, C.; Maiolino, R.; Marconi, A.; Menci, N.; Puccetti, S.; Veilleux, S.

    2015-11-01

    Mrk 231 is a nearby ultra-luminous IR galaxy exhibiting a kpc-scale, multi-phase AGN-driven outflow. This galaxy represents the best target to investigate in detail the morphology and energetics of powerful outflows, as well as their still poorly-understood expansion mechanism and impact on the host galaxy. In this work, we present the best sensitivity and angular resolution maps of the molecular disk and outflow of Mrk 231, as traced by CO(2-1) and (3-2) observations obtained with the IRAM/PdBI. In addition, we analyze archival deep Chandra and NuSTAR X-ray observations. We use this unprecedented combination of multi-wavelength data sets to constrain the physical properties of both the molecular disk and outflow, the presence of a highly-ionized ultra-fast nuclear wind, and their connection. The molecular CO(2-1) outflow has a size of 1 kpc, and extends in all directions around the nucleus, being more prominent along the south-west to north-east direction, suggesting a wide-angle biconical geometry. The maximum projected velocity of the outflow is nearly constant out to 1 kpc, thus implying that the density of the outflowing material must decrease from the nucleus outwards as r-2. This suggests that either a large part of the gas leaves the flow during its expansion or that the bulk of the outflow has not yet reached out to 1 kpc, thus implying a limit on its age of 1 Myr. Mapping the mass and energy rates of the molecular outflow yields dot {M} OF = [500-1000] M⊙ yr-1 and Ėkin,OF = [7-10] × 1043 erg s-1. The total kinetic energy of the outflow is Ekin,OF is of the same order of the total energy of the molecular disk, Edisk. Remarkably, our analysis of the X-ray data reveals a nuclear ultra-fast outflow (UFO) with velocity -20 000 km s-1, dot {M}UFO = [0.3-2.1] M⊙ yr-1, and momentum load dot {P}UFO/ dot {P}rad = [0.2-1.6]. We find Ėkin,UFO Ėkin,OF as predicted for outflows undergoing an energy conserving expansion. This suggests that most of the UFO

  3. ROSAT detection of diffuse hot gas in the edge-on galaxy NGC 4631

    NASA Technical Reports Server (NTRS)

    Wang, Q. David; Walterbos, Rene A. M.; Steakley, Michael F.; Norman, Colin A.; Braun, Robert

    1994-01-01

    ROSAT observation is presented of the edge-on spiral galaxy NGC 4631, a nearby Sc/SBd galaxy best known for its extended radio halo. Because of the low foreground Galactic X-ray-absorbing gas column density, N(sub H) approximately 1.4 x 10(exp 20)cm(exp -2), this observation is sensitive to gas of temperature greater than or equal to a few times 10(exp 5) K. A soft (approximately 0.25 keV) X-ray radiation out to more than 8 kpc above the midplane of the galaxy was detected. The strongest X-ray emission in the halo is above the central disk, a region of about 3 kpc radius which shows high star formation activity. The X-ray emission in the halo is bordered by two extended filaments of radio continuum emission. Diffuse X-ray emission from hot gas in the galaxy's disk was found. The spectrum of the radiation can be characterized by a thermal plasma with a temperature of 3 x 10(exp 6) K and a radiative cooling rate of approximately 8 x 10(exp 39) ergs s(exp -1). This rate is only a few percent of the estimated supernova energy release in the interstellar medium of the galaxy. Analysis of the X-ray spectrum shows evidence for the presence of a cooler (several times 10(exp 5) K) halo gas component that could consume a much larger fraction of the supernova energy. Strong evidence was found for disk/halo interaction. Hot gas apparently blows out from supershells in the galaxy's disk at a rate of approximately 1 solar mass yr(exp -1). This outflow of hot gas drags magnetic field lines up in the halo and forms a magnetized gaseous halo. If the magnetic field lines are still anchored to the disk gas at large disk radii, the outflowing gas may be confined high above the disk by magnetic pressure. A strong X-ray source which coincides spatially with an H I supershell has been identified. However, the source is likely an extremely luminous X-ray binary with L(sub chi)(0.1 - 2 keV) approximately 5 x 10(exp 39) ergs s(exp -1), which makes it a stellar mass black hole candidate.

  4. ON THE HOT GAS CONTENT OF THE MILKY WAY HALO

    SciTech Connect

    Fang, Taotao; Bullock, James; Boylan-Kolchin, Michael

    2013-01-01

    The Milky Way appears to be missing baryons, as the observed mass in stars and gas is well below the cosmic mean. One possibility is that a substantial fraction of the Galaxy's baryons are embedded within an extended, million-degree hot halo, an idea supported indirectly by observations of warm gas clouds in the halo and gas-free dwarf spheroidal satellites. X-ray observations have established that hot gas does exist in our Galaxy beyond the local hot bubble; however, it may be distributed in a hot disk configuration. Moreover, recent investigations into the X-ray constraints have suggested that any Galactic corona must be insignificant. Here we re-examine the observational data, particularly in the X-ray and radio bands, in order to determine whether it is possible for a substantial fraction of the Galaxy's baryons to exist in {approx}10{sup 6} K gas. In agreement with past studies, we find that a baryonically closed halo is clearly ruled out if one assumes that the hot corona is distributed with a cuspy Navarro-Frenk-White profile. However, if the hot corona of the galaxy is in an extended, low-density distribution with a large central core, as expected for an adiabatic gas in hydrostatic equilibrium, then it may contain up to 10{sup 11} M {sub Sun} of material, possibly accounting for all of the missing Galactic baryons. We briefly discuss some potential avenues for discriminating between a massive, extended hot halo and a local hot disk.

  5. Pilot scale experience on IGCC hot gas cleanup

    SciTech Connect

    Salo, K.; Ghazanfari, R.; Feher, G.

    1995-11-01

    In September 1993 Enviropower Inc. entered into a Cooperative Research and Development Agreement (CRADA) with the Department of Energy in order to develop and demonstrate the major components of an IGCC process such as hot gas cleanup systems. The objectives of the project are to develop and demonstrate: (1) hydrogen sulfide removal using regenerable metal oxide sorbent in pressurized fluidized bed reactors, (2) recovery of elemental sulfur from the tail-gas of the sorbent regenerator, and (3) hot gas particulate removal using ceramic candle filters.

  6. THE GAS INFLOW AND OUTFLOW RATE IN STAR-FORMING GALAXIES AT z ∼ 1.4

    SciTech Connect

    Yabe, Kiyoto; Ohta, Kouji; Iwamuro, Fumihide; Akiyama, Masayuki; Tamura, Naoyuki; Yuma, Suraphong; Dalton, Gavin; Lewis, Ian

    2015-01-01

    We try to constrain the gas inflow and outflow rate of star-forming galaxies at z ∼ 1.4 by employing a simple analytic model for the chemical evolution of galaxies. The sample is constructed based on a large near-infrared spectroscopic sample observed with Subaru/FMOS. The gas-phase metallicity is measured from the [N II] λ6584/Hα emission line ratio and the gas mass is derived from the extinction corrected Hα luminosity by assuming the Kennicutt-Schmidt law. We constrain the inflow and outflow rate from the least-χ{sup 2} fittings of the observed gas-mass fraction, stellar mass, and metallicity with the analytic model. The joint χ{sup 2} fitting shows that the best-fit inflow rate is ∼1.8 and the outflow rate is ∼0.6 in units of star-formation rate. By applying the same analysis to the previous studies at z ∼ 0 and z ∼ 2.2, it is shown that both the inflow and outflow rates decrease with decreasing redshift, which implies the higher activity of gas flow process at higher redshift. The decreasing trend of the inflow rate from z ∼ 2.2 to z ∼ 0 agrees with that seen in previous observational works with different methods, though the absolute value is generally larger than in previous works. The outflow rate and its evolution from z ∼ 2.2 to z ∼ 0 obtained in this work agree well with the independent estimations in previous observational works.

  7. Hot particulate removal and desulfurization results from the METC integrated gasification and hot gas cleanup facility

    SciTech Connect

    Rockey, J.M.

    1995-06-01

    The Morgantown Energy Technology Center (METC) is conducting experimental testing using a 10-inch diameter fluid-bed gasifier (FBG) and modular hot gas cleanup rig (MGCR) to develop advanced methods for removing contaminants in hot coal gasifier gas streams for commercial development of integrated gasification combined-cycle (IGCC) power systems. The program focus is on hot gas particulate removal and desulfurization technologies that match the temperatures and pressures of the gasifier, cleanup system, and power generator. The purpose of this poster is to present the program objectives and results of the work conducted in cooperation with industrial users and vendors to meet the vision for IGCC of reducing the capital cost per kilowatt to $1050 and increasing the plant efficiency to 52% by the year 2010.

  8. Determining the Origins and Impact of Hot Gas in the Milky Way

    NASA Astrophysics Data System (ADS)

    Miller, Matthew J.; Bregman, Joel N.; Hodges-Kluck, Edmund J.

    2016-01-01

    The Milky Way's circumgalactic medium contains million degree gas that is volume-filling on ≥10 kpc scales based on X-ray emission from the ROSAT All-Sky Survey, detections of OVII Kα (λ=21.602 Å) absorption lines at z~0 in AGN spectra, ubiquitous detections of OVII-OVIII emission lines in ~1,000 blank-sky spectra, and the discovery of the ~10 kpc outflow from the Galactic center known as the Fermi bubbles. Analyses on the line strengths in individual or small samples of sight lines (< 30) imply plasma densities between 10-5-10-2 cm-3, but the dominant hot gas structure is argued to be either a disk morphology (~108 M⊙ of material) or a spherical morphology (1010-1011 M⊙ of material). This is a crucial distinction since these morphologies arise from significantly different galaxy evolution processes, and the Fermi bubbles are recently discovered objects that are interacting with the ambient CGM. In this dissertation, I constrain the global hot gas density structure by comparing the largest samples of OVII equivalent width measurements and OVII-OVIII line intensities with model line strengths from parametric density models. I find that a spherical profile with n ∝ r-3/2 extending to the Milky Way's virial radius results in model line strenghts that are most consistent with how the observed line strengths vary across the sky. These results imply a hot gas mass between 2-5 x 1010 M⊙ within 250 kpc (≤ 50% of the Galactic missing baryons), a hot gas metallicity of Z ≥ .3 Z⊙, and that most of the hot gas formed as shock-heated material during the Milky Way's formation. For the Fermi bubbles, the line intensities and ratios suggest they contain hotter gas than the surrounding medium (> 2 x 106 K) and densities between 10-4-10-3 cm-3. This implies the bubbles are over-pressurized and expanding into the surrounding halo, potentially heating and displacing the ambient CGM.

  9. Development of hot gas filtration for air blown gasification plant

    SciTech Connect

    Cahill, P.; Dutton, M.; Tustin, M.; Rasmussen, G.; Sage, P.

    1995-12-31

    This paper describes some of the development work carried out on hot gas filtration for the Air Blown Gasification Cycle (ABGC). The ABGC comprises partial gasification of coal at elevated pressure with combustion of the fuel gas produced in a gas turbine. The residual carbon from gasification is burned in an atmospheric pressure circulating fluidized bed combustor raising steam to drive a steam turbine. A critical requirement in the ABGC is to ensure that the fuel gas is free of dust, in order to avoid damage to the gas turbine. Ceramic filter elements are the preferred technology for this clean-up. The required operating temperature is 400--600 C, based on optimizing efficiency and to allow use of other hot gas clean-up systems, for instance for sulfur polishing. A development program on hot gas filtration has been carried out at CTDD in order to ensure that this component of the cycle can be used with minimum risk. To date, over 2,000 h of operation at up to 600 C has been achieved on two pilot scale hot gas filters, each taking full flow of gas from air blown gasifiers. The filters have operated with high availability and there have been no incidents of breakage of filter elements. Information has been generated for effect of filtration velocity and temperature, cleaning gas requirements, changing dust and gas composition, and for design of critical components such as fast opening valves, venturi ejectors and sealing mechanisms. The effect of different operating conditions on filter element strength has been evaluated for a range of filter elements.

  10. Ceramic filters for removal of particulates from hot gas streams

    SciTech Connect

    Goldsmith, R.L.

    1992-11-01

    The primary goal is to demonstrate the performance of a new ceramic filter in removing particulate matter from hot gas streams produced in advanced coal conversion processes. The specific objectives are threefold: (1) Development of full size ceramic filters suitable for hot gas filtration; (2) Demonstration of ceramic filters in long term (ca. 1000 hrs) field trials; and (3) Development of full-scale hot gas filter system designs and costs. To date, field tests of the ceramic filter for particulate removal have been conducted at seven sites on a variety of gas streams and under a variety of test conditions. In general, the following performance characteristics have been observed: 1. Filtration face velocity (equivalent to an ``air to cloth ratio``) for flue gas tests is comparable to that for pulse jet bags operating at the same pressure drop. In hot gas tests, flow-pressure drop characteristics have been observed to be comparable to those for other ceramic filters. 2. Complete regeneration by a simple backpulse technique is achieved; i.e., no increase in clean filter resistance over repetitive cycles is observed. 3. No plugging of the filter passageways by badly caking particulates is observed. 4. Essentially complete particulate removal, including submicron particulate matter, is achieved.

  11. Ceramic filters for removal of particulates from hot gas streams

    SciTech Connect

    Goldsmith, R.L.

    1992-01-01

    The primary goal is to demonstrate the performance of a new ceramic filter in removing particulate matter from hot gas streams produced in advanced coal conversion processes. The specific objectives are threefold: (1) Development of full size ceramic filters suitable for hot gas filtration; (2) Demonstration of ceramic filters in long term (ca. 1000 hrs) field trials; and (3) Development of full-scale hot gas filter system designs and costs. To date, field tests of the ceramic filter for particulate removal have been conducted at seven sites on a variety of gas streams and under a variety of test conditions. In general, the following performance characteristics have been observed: 1. Filtration face velocity (equivalent to an air to cloth ratio'') for flue gas tests is comparable to that for pulse jet bags operating at the same pressure drop. In hot gas tests, flow-pressure drop characteristics have been observed to be comparable to those for other ceramic filters. 2. Complete regeneration by a simple backpulse technique is achieved; i.e., no increase in clean filter resistance over repetitive cycles is observed. 3. No plugging of the filter passageways by badly caking particulates is observed. 4. Essentially complete particulate removal, including submicron particulate matter, is achieved.

  12. Biomass gasification hot gas cleanup demonstration program status

    SciTech Connect

    Wiant, B.C.; Bachovchin, D.M.; Onischak, M.

    1994-12-31

    In support of the U.S. Department of Energy`s Biomass Power Program, Westinghouse Electric has been conducting research and development of a hot gas cleaning system compatible with a pressurized fluidized bed biomass gasifier and the operation of a gas turbine. The hot gas cleanup system must be capable of filtering out the flyash particulates at gasifier operating conditions, dealing with the feedstock`s inherent tars and oils, and removing excessive levels of alkali. The Westinghouse led team consisting of the Institute of Gas Technology, Gilbert/Commonwealth, and the Pacific International Center for High Technology Research began work in April 1993 on this 30 month program. Status of the program is: hot gas cleanup (HGCU) requirements and system evaluation have been completed; the hot gas cleanup filter system has been designed, fabricated and installed in the 10 ton-per-day process development unit (PDU) at IGT in Chicago, IL; a tar cracker has been designed, fabricated and installed in the PDU; the testing plan has been developed; PDU modifications have been completed along with complete facility shakedown; and testing of the cleanup system is in process. This paper discusses the status of each of the major program elements described above.

  13. Hot-Gas Filter Testing with a Transport Reactor Gasifier

    SciTech Connect

    Swanson, M.L.; Hajicek, D.R.

    2002-09-18

    Today, coal supplies over 55% of the electricity consumed in the United States and will continue to do so well into the next century. One of the technologies being developed for advanced electric power generation is an integrated gasification combined cycle (IGCC) system that converts coal to a combustible gas, cleans the gas of pollutants, and combusts the gas in a gas turbine to generate electricity. The hot exhaust from the gas turbine is used to produce steam to generate more electricity from a steam turbine cycle. The utilization of advanced hot-gas particulate and sulfur control technologies together with the combined power generation cycles make IGCC one of the cleanest and most efficient ways available to generate electric power from coal. One of the strategic objectives for U.S. Department of Energy (DOE) IGCC research and development program is to develop and demonstrate advanced gasifiers and second-generation IGCC systems. Another objective is to develop advanced hot-gas cleanup and trace contaminant control technologies. One of the more recent gasification concepts to be investigated is that of the transport reactor gasifier, which functions as a circulating fluid-bed gasifier while operating in the pneumatic transport regime of solid particle flow. This gasifier concept provides excellent solid-gas contacting of relatively small particles to promote high gasification rates and also provides the highest coal throughput per unit cross-sectional area of any other gasifier, thereby reducing capital cost of the gasification island.

  14. The long lives of giant clumps and the birth of outflows in gas-rich galaxies at high redshift

    SciTech Connect

    Bournaud, Frédéric; Renaud, Florent; Daddi, Emanuele; Duc, Pierre-Alain; Elbaz, David; Gabor, Jared M.; Juneau, Stéphanie; Kraljic, Katarina; Le Floch', Emeric; Dekel, Avishai; Elmegreen, Bruce G.; Elmegreen, Debra M.; Teyssier, Romain

    2014-01-01

    Star-forming disk galaxies at high redshift are often subject to violent disk instability, characterized by giant clumps whose fate is yet to be understood. The main question is whether the clumps disrupt within their dynamical timescale (≤50 Myr), like the molecular clouds in today's galaxies, or whether they survive stellar feedback for more than a disk orbital time (≈300 Myr) in which case they can migrate inward and help building the central bulge. We present 3.5-7 pc resolution adaptive mesh refinement simulations of high-redshift disks including photoionization, radiation pressure, and supernovae feedback. Our modeling of radiation pressure determines the mass loading and initial velocity of winds from basic physical principles. We find that the giant clumps produce steady outflow rates comparable to and sometimes somewhat larger than their star formation rate, with velocities largely sufficient to escape the galaxy. The clumps also lose mass, especially old stars, by tidal stripping, and the stellar populations contained in the clumps hence remain relatively young (≤200 Myr), as observed. The clumps survive gaseous outflows and stellar loss, because they are wandering in gas-rich turbulent disks from which they can reaccrete gas at high rates compensating for outflows and tidal stripping, overall keeping realistic and self-regulated gaseous and stellar masses. The outflow and accretion rates have specific timescales of a few 10{sup 8} yr, as opposed to rapid and repeated dispersion and reformation of clumps. Our simulations produce gaseous outflows with velocities, densities, and mass loading consistent with observations, and at the same time suggest that the giant clumps survive for hundreds of Myr and complete their migration to the center of high-redshift galaxies. These long-lived clumps are gas-dominated and contain a moderate mass fraction of stars; they drive inside-out disk evolution, thickening, spheroid growth, and fueling of the central

  15. PERFORMANCE AND MODELING OF A HOT POTASSIUM CARBONATE ACID GAS REMOVAL SYSTEM IN TREATING COAL GAS

    EPA Science Inventory

    The report discusses the performance and modeling of a hot potassium carbonate (K2CO3) acid gas removal system (AGRS) in treating coal gas. Aqueous solutions of K2CO3, with and without amine additive, were used as the acid gas removal solvent in the Coal Gasification/Gas Cleaning...

  16. Heat pipe with hot gas reservoir

    NASA Technical Reports Server (NTRS)

    Marcus, B. D.

    1974-01-01

    Heat pipe can reverse itself with gas reservoir acting as evaporator, leading to rapid recovery from liquid in reservoir. Single layer of fine-mesh screen is included inside reservoir to assure uniform liquid distribution over hottest parts of internal surface until liquid is completely removed.

  17. Hot gas and the evolution of spiral-rich groups

    NASA Astrophysics Data System (ADS)

    Vrtilek, Jan M.; O'Sullivan, E. J.; Giacintucci, S.; David, L. P.; Raychaudhury, S.; Forman, W. R.; Jones, C.

    2014-01-01

    The group environment --- the locus of most galaxies in the present-day Universe --- is particularly suitable, owing to high galaxy densities and low velocity dispersions, for study of the merging of spirals to form ellipticals. In particular, little is known about how the resulting ellipticals acquire hot gas halos (whether from stellar mass loss or from accretion of group gas). We here discuss our examination, relying principally on Chandra and GMRT data, of two groups that are at once compact, spiral-dominated, sufficiently X-ray bright, nearby, and in early stages of merging. For HCG92 (Stephan’s Quintet), GMRT 610 and 327 MHz observations show diffuse extended radio emission. X-ray and radio emissions from the group are dominated by a bright north-south ridge associated with the interloper galaxy NGC 7318b, with the low temperature of X-ray gas (0.6 keV) indicating an oblique shock resulting from the interaction. Much of the gas now in the hot phase may have been produced by shock heating of cool material during galaxy interactions, with additional energy and metals injected by star formation. Radio spectral index mapping allows us to trace the relative contributions from the shock and from star formation. Within the ridge spectral information can also be used to estimate the radiative age of the electron population, providing information on the shock age. For HCG16 the nature and even the existence of a hot intragroup medium has been debated. With a combination of a very recent deep (150 ks) Chandra image and radio data already available, we expect to resolve questions about the existence, extent, and nature of hot gas in HCG 16; map the heavy element distribution; determine the hot gas mass compared to the HI deficit; examine the prevalence of shock heating and ram pressure stripping; and study the brightest point sources.

  18. The hot gas content of fossil galaxy clusters

    NASA Astrophysics Data System (ADS)

    Pratt, G. W.; Pointecouteau, E.; Arnaud, M.; van der Burg, R. F. J.

    2016-05-01

    We investigate the properties of the hot gas in four fossil galaxy systems detected at high significance in the Planck Sunyaev-Zeldovich (SZ) survey. XMM-Newton observations reveal overall temperatures of kT ~ 5-6 keV and yield hydrostatic masses M500,HE ≳ 3.5 × 1014M⊙, confirming their nature as bona fide massive clusters. We measure the thermodynamic properties of the hot gas in X-rays (out to beyond R500 in three cases) and derive their individual pressure profiles out to R ~ 2.5 R500 with the SZ data. We combine the X-ray and SZ data to measure hydrostatic mass profiles and to examine the hot gas content and its radial distribution. The average Navarro-Frenk-White (NFW) concentration parameter, ⟨ c500 ⟩ = 3.2 ± 0.4, is the same as that of relaxed "normal" clusters. The gas mass fraction profiles exhibit striking variation in the inner regions, but converge to approximately the cosmic baryon fraction (corrected for depletion) at R500. Beyond R500 the gas mass fraction profiles again diverge, which we interpret as being due to a difference in gas clumping and/or a breakdown of hydrostatic equilibrium in the external regions. Our observations point to considerable radial variation in the hot gas content and in the gas clumping and/or hydrostatic equilibrium properties in these fossil clusters, at odds with the interpretation of their being old, evolved, and undisturbed. At least some fossil objects appear to be dynamically young.

  19. Task 3.13 - Hot-Gas Filter Testing

    SciTech Connect

    Michael L. Swanson

    1998-01-01

    The objectives of the hot-gas cleanup (HGC) work on the transport reactor demonstration unit (TRDU) located at the Energy and Environmental Research Center (EERC) is to demonstrate acceptable performance of hot-gas filter elements in a pilot-scale system prior to long-term demonstration tests. The primary focus of the experimental effort in the 3-year project is the testing of hot-gas filter element performance (particulate collection efficiency, filter pressure differential, filter cleanability, and durability) as a fiction of temperature and filter face velocity during short-term operation (100-200 hours). The filter vessel is used in combination with the TRDU to evaluate the performance of selected hot-gas filter elements under gasification operating conditions. This work directly supports the power systems development facility (PSDF) utilizing the M.W. Kellogg transport reactor located at Wilsonville, Alabama (1) and, indirectly, the Foster Wheeler advanced pressurized fluid-bed combustor, also located at Wilsonville (2).

  20. 25. Wood quench tower, chemical tank on right, hot gas ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. Wood quench tower, chemical tank on right, hot gas pipes between coke ovens and compressor building XX), coal conveyor to pulverizer building on right, water tank to left of quench tower. Looking north/northwest - Rouge Steel Company, 3001 Miller Road, Dearborn, MI

  1. Core-in-shell sorbent for hot coal gas desulfurization

    DOEpatents

    Wheelock, Thomas D.; Akiti, Jr., Tetteh T.

    2004-02-10

    A core-in-shell sorbent is described herein. The core is reactive to the compounds of interest, and is preferably calcium-based, such as limestone for hot gas desulfurization. The shell is a porous protective layer, preferably inert, which allows the reactive core to remove the desired compounds while maintaining the desired physical characteristics to withstand the conditions of use.

  2. Closed Loop Test Facility for hot dirty gas valves

    SciTech Connect

    Not Available

    1980-02-06

    A design study of a closed loop test facility for eight-inch hot dirty gas valves is presented. The objective of the facility is to quality valves for use in coal gasifiers, combined cycle plants, and pressurized fluid bed combustors. Outline sketches and estimated costs are presented for the selected design.

  3. NANOMATERIAL SOLUTIONS FOR HOT COAL GAS CLEANUP - PHASE I

    EPA Science Inventory

    Integrated gasification combined cycle (IGCC) is a new coal gasification technique that efficiently uses the hot (900-1500°C) generated syngas to power both steam and gas turbines. Due to regulations, this syngas must be free of sulfur and purification is normally carried ...

  4. Asbestos and Inconel combined to form hot-gas seal

    NASA Technical Reports Server (NTRS)

    Wooster, C. W., Jr.

    1968-01-01

    Hot-gas seal prevents warpage tendencies in large flange joints exposed to high temperatures, such as those present in large space vehicle engine exhausts. Two Inconel wire mesh cores are held in place by an asbestos cloth cover that acts as a spacer to form the seal.

  5. Modeling of Gas and Dust Outflow Dynamics at Active Small Solar System Bodies

    NASA Astrophysics Data System (ADS)

    Fahnestock, Eugene G.

    2013-05-01

    Abstract (2,250 Maximum Characters): We present methodology and results from our recent effort in modeling the gas outflow from the surfaces of primitive/active small solar system bodies, and modeling the dynamics of dust particles entrained by that flow. We based our initial simulation capability on the COMA software package, developed ≈1995-1999 for ESA to enable studies preparatory to Rosetta. Rather than integrate the derived software for gas and dust dynamics simulation "into the loop" within high-fidelity 6DOF integration of a rendezvoused spacecraft's dynamics, we created simple tools, or "interfaces", computationally efficient enough to be brought into the loop, yet capturing the variety of ways in which gas and lifted dust can potentially perturb guidance, navigation, and control (GN&C) performance and surface observation performance. For example, these interfaces are called in the loop to compute noise models for degradation by the dust of imagery and lidar navigation observables. The same applies for degradation of science instrument observations of the surface. Accurate spacecraft dynamics propagation is necessary for mission design, while both that and the observables modeling are required for end-to-end simulation and analysis of navigation and control to the designed close-proximity trajectories. We created interfaces with increasing levels of fidelity, ultimately sufficiently approximating the full flow-field of gas and dust activity; both diffuse background activity (with spatial variation in relation to sun direction) and concentrated jet activity (with spatial and temporal variation through masking to the regions of jet activity in the body-fixed frame and modeling body rotation). We show example results using these tools for two representative design reference missions involving 9P/Tempel 1 and 67P/C-G. This work should be of interest to anyone in the DDA community considering involvement in such mission scenarios. It may also be extended in

  6. DEVELOPMENT OF METALLIC HOT GAS FILTERS

    SciTech Connect

    Anderson, I.E.; Gleeson, B.; Terpstra, R.L.

    2003-04-23

    Successful development of metallic filters with high temperature oxidation/corrosion resistance for fly ash capture is a key to enabling advanced coal combustion and power generation technologies. Compared to ceramic filters, metallic filters can offer increased resistance to impact and thermal fatigue, greatly improving filter reliability. A beneficial metallic filter structure, composed of a thin-wall (0.5mm) tube with uniform porosity (about 30%), is being developed using a unique spherical powder processing and partial sintering approach, combined with porous sheet rolling and resistance welding. Alloy choices based on modified superalloys, e.g., Ni-16Cr-4.5Al-3Fe (wt.%), are being tested in porous and bulk samples for oxide (typically alumina) scale stability in simulated oxidizing/sulfidizing atmospheres found in PFBC and IGCC systems at temperatures up to 850 C. Recent ''hanging o-ring'' exposure tests in actual combustion systems at a collaborating DOE site (EERC) have been initiated to study the combined corrosive effects from particulate deposits and hot exhaust gases. New studies are exploring the correlation between sintered microstructure, tensile strength, and permeability of porous sheet samples.

  7. Hot Gas Cleanup Test Facility for Gasification and Pressurized Combustion

    SciTech Connect

    Sears, R.E.; Griswold, G.H.; Fankhanel, M.O.; Kastner, C.E.; Pontium, D.H.

    1992-11-01

    Efficiencies in advanced power generation systems such as integrated gasification combined cycle, pressurized fluidized bed combustion and integrated gasification fuel cells can be maximized by feeding hot fuel gas or flue gas to the power block. However, advanced gas turbines have strict particulate requirements to minimize wear on the blades due to the close tolerances used to maximize the efficiency of the turbomachinery. Molten Carbonate Fuel Cells also have strict particulate requirements to prevent blinding of the electrodes. Therefore, one of the main barriers to developing these advanced power generation systems is the removal of particulates in a hot gas stream. Although the development of several high temperature/pressure PCD systems has been ongoing for the past several years, long term operation under realistic conditions for advanced power generation has been limited. The demonstration of reliable operation is critical to the commercialization of PCD technology for advanced power generation. The conceptual design of the Hot Gas Cleanup Test Facility Project was expanded to include additional modules to better address the scope of the Cooperative Agreement with the DOE/METC. The expanded test facility, referred to as the Power Systems Development Facility, will provide a flexible test location in which the development of advanced power system components, the evaluation of advanced turbine and fuel cell configurations, and the integration and control issues of these systems. The facility is intended to provide direct support for upcoming DOE demonstrations of power generation technologies utilizing hot stream cleanup and will provide a resource for rigorous testing and performance assessment of hot stream cleanup devices now being developed with the support of DOE/METC.

  8. Sorbent for use in hot gas desulfurization

    DOEpatents

    Gasper-Galvin, Lee D.; Atimtay, Aysel T.

    1993-01-01

    A multiple metal oxide sorbent supported on a zeolite of substantially silicon oxide is used for the desulfurization of process gas streams, such as from a coal gasifier, at temperatures in the range of about 1200.degree. to about 1600.degree. F. The sorbent is provided by a mixture of copper oxide and manganese oxide and preferably such a mixture with molybdenum oxide. The manganese oxide and the molybdenum are believed to function as promoters for the reaction of hydrogen sulfide with copper oxide. Also, the manganese oxide inhibits the volatilization of the molybdenum oxide at the higher temperatures.

  9. NEUTRAL GAS OUTFLOWS AND INFLOWS IN INFRARED-FAINT SEYFERT GALAXIES

    SciTech Connect

    Krug, Hannah B.; Veilleux, Sylvain; Rupke, David S. N. E-mail: veilleux@astro.umd.ed

    2010-01-10

    Previous studies of the Na I D interstellar absorption line doublet have shown that galactic winds occur in most galaxies with high infrared luminosities. However, in infrared-bright composite systems where a starburst coexists with an active galactic nucleus (AGN), it is unclear whether the starburst, the AGN, or both are driving the outflows. The present paper describes the results from a search for outflows in 35 infrared-faint Seyferts with 10{sup 9.9}< L{sub IR}/L{sub sun} < 10{sup 11}, or, equivalently, star formation rates (SFRs) of approx0.4-9 M{sub sun} yr{sup -1}, to attempt to isolate the source of the outflow. We find that the outflow detection rates for the infrared-faint Seyfert 1s (6%) and Seyfert 2s (18%) are lower than previously reported for infrared-luminous Seyfert 1s (50%) and Seyfert 2s (45%). The outflow kinematics of infrared-faint and infrared-bright Seyfert 2 galaxies resemble those of starburst galaxies, while the outflow velocities in Seyfert 1 galaxies are significantly larger. Taken together, these results suggest that the AGN does not play a significant role in driving the outflows in most infrared-faint and infrared-bright systems, except the high-velocity outflows seen in Seyfert 1 galaxies. Another striking result of this study is the high rate of detection of inflows in infrared-faint galaxies (39% of Seyfert 1s, 35% of Seyfert 2s), significantly larger than in infrared-luminous Seyferts (15%). This inflow may be contributing to the feeding of the AGN in these galaxies, and potentially provides more than enough material to power the observed nuclear activity over typical AGN lifetimes.

  10. Modeling Hot Gas Flow in the Low-Luminosity Active Galactic Nucleus of NGC3115

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Roman V.; Wong, K.; Irwin, J.; Reynolds, C. S.

    2014-01-01

    Based on the dynamical estimates of the black hole (BH) mass, NGC3115 hosts the closest billion solar mass BH. Deep studies of the center revealed a very underluminous active galactic nucleus (AGN) immersed in an old massive nuclear star cluster. Recent 1Ms Chandra X-ray visionary project observations of the NGC3115 nucleus resolved hot tenuous gas, which fuels the AGN. In this work we connect the processes in the nuclear star cluster with the feeding of the supermassive BH. We model the hot gas flow sustained by the injection of matter and energy by the stars and supernova explosions. We incorporate electron heat conduction, the gravitational pull of the stellar mass, cooling, and Coulomb collisions. We reach reduced χi^2=1 fitting simulated X-ray emission to the spatially and spectrally resolved observed X-ray data. Radial modeling favors a low BH mass <1.3*10^{9}Msun. The best-fitting supernova rate and the best-fitting mass injection rate are consistent with their expected values. The stagnation point is at r_ s 1arcsec, so that most of gas, including the gas at a Bondi radius r_B=2-4arcsec, outflows from the region. We put an upper limit on the accretion rate at 2*10^{-3}Msun/yr. We find a shallow density profile r^{-β} with β 1 over a large dynamic range. This density profile is determined in the feeding region 0.5-10arcsec as an interplay of four processes and effects: (1) the radius-dependent mass injection, (2) the effect of the galactic gravitational potential, (3) the accretion flow onset at r<1arcsec, and (4) the outflow at r>1arcsec. Conduction makes the density profile shallow only very close to the BH at r<0.1arcsec. The gas temperature is close to the virial temperature T_v at any radius. The temperature profile is shallow outside of the Bondi radius because the enclosed stellar mass is proportional to radius M_en r, which leads to flat virial temperature profile.

  11. Modeling hot gas flow in the low-luminosity active galactic nucleus of NGC 3115

    SciTech Connect

    Shcherbakov, Roman V.; Reynolds, Christopher S.; Wong, Ka-Wah; Irwin, Jimmy A.

    2014-02-20

    Based on the dynamical black hole (BH) mass estimates, NGC 3115 hosts the closest billion solar mass BH. Deep studies of the center revealed a very underluminous active galactic nucleus (AGN) immersed in an old massive nuclear star cluster. Recent 1 Ms Chandra X-ray visionary project observations of the NGC 3115 nucleus resolved hot tenuous gas, which fuels the AGN. In this paper we connect the processes in the nuclear star cluster with the feeding of the supermassive BH. We model the hot gas flow sustained by the injection of matter and energy from the stars and supernova explosions. We incorporate electron heat conduction as the small-scale feedback mechanism, the gravitational pull of the stellar mass, cooling, and Coulomb collisions. Fitting simulated X-ray emission to the spatially and spectrally resolved observed data, we find the best-fitting solutions with χ{sup 2}/dof = 1.00 for dof = 236 both with and without conduction. The radial modeling favors a low BH mass <1.3 × 10{sup 9} M {sub ☉}. The best-fitting supernova rate and the best-fitting mass injection rate are consistent with their expected values. The stagnation point is at r {sub st} ≲ 1'', so that most of the gas, including the gas at a Bondi radius r{sub B} = 2''-4'', outflows from the region. We put an upper limit on the accretion rate at 2 × 10{sup –3} M {sub ☉} yr{sup –1}. We find a shallow density profile n∝r {sup –β} with β ≈ 1 over a large dynamic range. This density profile is determined in the feeding region 0.''5-10'' as an interplay of four processes and effects: (1) the radius-dependent mass injection, (2) the effect of the galactic gravitational potential, (3) the accretion flow onset at r ≲ 1'', and (4) the outflow at r ≳ 1''. The gas temperature is close to the virial temperature T{sub v} at any radius.

  12. Hot and cold gas toward young stellar objects

    NASA Technical Reports Server (NTRS)

    Mitchell, George F.; Maillard, Jean-Pierre; Allen, Mark; Beer, Reinhard; Belcourt, Kenneth

    1990-01-01

    High-resolution M band spectra are presented for the seven embedded IR sources W3 IRS 5, S140 IRS1, NGC 7538 IRS 1, NGC 7538 IRS 9, GL 2136, LkH-alpha 101, and MWC 349A, and the data are combined with previously published work for W33A and GL 2591. Cold CO is seen toward all nine sources, with temperatures from 11 K to 66 K. Column densities of cold CO are presented. Hot gas is seen toward eight of the nine objects with temperatures from 120 K to 1010 K. New lower limits to the hot gas density are obtained. The hot gas toward GL 2591, GL 2136, W3 IRS 5, and S140 IRS 1 is probably very near the central source and heated via gas-grain collisions. The optical depth in the silicate feature is strongly correlated with the (C-13)O column density, confirming that silicate optical depth is a useful measure of gas column density. The ratio of solid-to-gaseous CO is obtained for seven sources.

  13. Hot and cold gas toward young stellar objects

    SciTech Connect

    Mitchell, G.F.; Maillard, J.; Allen, M.; Beer, R.; Belcourt, K. Canada-France-Hawaii Telescope Corp., Waimea, HI CNRS, Institut d'Astrophysique, Paris JPL, Pasadena, CA )

    1990-11-01

    High-resolution M band spectra are presented for the seven embedded IR sources W3 IRS 5, S140 IRS1, NGC 7538 IRS 1, NGC 7538 IRS 9, GL 2136, LkH-alpha 101, and MWC 349A, and the data are combined with previously published work for W33A and GL 2591. Cold CO is seen toward all nine sources, with temperatures from 11 K to 66 K. Column densities of cold CO are presented. Hot gas is seen toward eight of the nine objects with temperatures from 120 K to 1010 K. New lower limits to the hot gas density are obtained. The hot gas toward GL 2591, GL 2136, W3 IRS 5, and S140 IRS 1 is probably very near the central source and heated via gas-grain collisions. The optical depth in the silicate feature is strongly correlated with the (C-13)O column density, confirming that silicate optical depth is a useful measure of gas column density. The ratio of solid-to-gaseous CO is obtained for seven sources. 43 refs.

  14. BENCH-SCALE DEMONSTRATION OF HOT-GAS DESULFURIZATION TECHNOLOGY

    SciTech Connect

    Unknown

    2000-09-01

    The U.S. Department of Energy (DOE), National Energy Technology Laboratory (NETL), is sponsoring research in advanced methods for controlling contaminants in hot coal gasifier gas (coal-derived fuel-gas) streams of integrated gasification combined-cycle (IGCC) power systems. The hot gas cleanup work seeks to eliminate the need for expensive heat recovery equipment, reduce efficiency losses due to quenching, and minimize wastewater treatment costs. Hot-gas desulfurization research has focused on regenerable mixed-metal oxide sorbents that can reduce the sulfur in coal-derived fuel-gas to less than 20 ppmv and can be regenerated in a cyclic manner with air for multicycle operation. Zinc titanate (Zn{sub 2}TiO{sub 4} or ZnTiO{sub 3}), formed by a solid-state reaction of zinc oxide (ZnO) and titanium dioxide (TiO{sub 2}), is currently one of the leading sorbents. Overall chemical reactions with Zn{sub 2}TiO{sub 4} during the desulfurization (sulfidation)-regeneration cycle are shown. The sulfidation/regeneration cycle can be carried out in a fixed-bed, moving-bed, or fluidized-bed reactor configuration. The fluidized-bed reactor configuration is most attractive because of several potential advantages including faster kinetics and the ability to handle the highly exothermic regeneration to produce a regeneration offgas containing a constant concentration of SO{sub 2}.

  15. Extended warm gas in the ULIRG Mrk273: Galactic outflows and tidal debris

    NASA Astrophysics Data System (ADS)

    Rodríguez Zaurín, J.; Tadhunter, C. N.; Rupke, D. S. N.; Veilleux, S.; Spoon, H. W. W.; Chiaberge, M.; Ramos Almeida, C.; Batcheldor, D.; Sparks, W. B.

    2014-11-01

    We present new HST/ACS medium- and narrow-band images and optical Isaac Newton Telescope long-slit spectra of the merging system Mrk273. The HST observations sample the [OIII]λλ4959,5007 emission from the galaxy and the nearby continuum. These data were taken as a part of a larger study of ultraluminous infrared galaxies (ULIRGs) with the aim of investigating the importance of the warm, AGN induced outflows in such objects. The HST images show that the morphologies of the extended continuum and the ionised gas emission from the galaxy are decoupled, extending almost perpendicular to each other. In particular, we detect for the first time a spectacular structure of ionised gas in the form of filaments and clumps that extend ~23 kpc to the east of the nuclear region. The quiescent ionised gas kinematics at these locations suggests that these filaments are tidal debris left over from a secondary merger event that are illuminated by an AGN in the nuclear regions. The images also reveal a complex morphology in the nuclear region of the galaxy for both the continuum and the [OIII] emission. Consistent with this complexity, we find a wide diversity of emission line profiles in these regions. Kinematic disturbance in the form of broad (FWHM> 500 km s-1) and/or strongly shifted (| ΔV | > 150 km s-1 ) emission line components is found at almost all locations in the nuclear regions, but confined to a radius of ~4 kpc to the east and west of the northern nucleus. In most cases, we are able to fit the profiles of all the emission lines of different ionisation with a kinematic model using two or three Gaussian components. From these fits, we derive diagnostic line ratios that are used to investigate the ionisation mechanisms at the different locations in the galaxy. We show that these line ratios are generally consistent with photoionisation by an AGN as the main ionisation mechanism. Finally, the highest surface brightness [OIII] emission is found in a compact region that is

  16. Evidence for feedback in action from the molecular gas content in the z ~ 1.6 outflowing QSO XID2028

    NASA Astrophysics Data System (ADS)

    Brusa, M.; Feruglio, C.; Cresci, G.; Mainieri, V.; Sargent, M. T.; Perna, M.; Santini, P.; Vito, F.; Marconi, A.; Merloni, A.; Lutz, D.; Piconcelli, E.; Lanzuisi, G.; Maiolino, R.; Rosario, D.; Daddi, E.; Bongiorno, A.; Fiore, F.; Lusso, E.

    2015-06-01

    Aims: Gas outflows are believed to play a pivotal role in shaping galaxies, as they regulate both star formation and black hole growth. Despite their ubiquitous presence, the origin and the acceleration mechanism of these powerful and extended winds is not yet understood. Direct observations of the cold gas component in objects with detected outflows at other wavelengths are needed to assess the impact of the outflow on the host galaxy interstellar medium (ISM). Methods: We observed with the Plateau de Bure Interferometer an obscured quasar at z ~ 1.5, XID2028, for which the presence of an ionized outflow has been unambiguously signalled by NIR spectroscopy. The detection of 12CO(3-2) emission in this source allows us to infer the molecular gas content and compare it to the ISM mass derived from the dust emission. We then analyzed the results in the context of recent insights on scaling relations, which describe the gas content of the overall population of star-forming galaxies at a similar redshifts. Results: The star formation efficiency (~100) and gas mass (Mgas = 2.1-9.5 × 1010 M⊙) inferred from the CO(3-2) line depend on the underlying assumptions on the excitation of the transition and the CO-to-H2 conversion factor. However, the combination of this information and the ISM mass estimated from the dust mass suggests that the ISM/gas content of XID2028 is significantly lower than expected for its observed M⋆, sSFR and redshift, based on the most up-to-date calibrations (with gas fraction <20% and depletion timescale <340 Myr). Conclusions: Overall, the constraints we obtain from the far infrared and millimeter data suggest that we are observing QSO feedback able to remove the gas from the host. Based on observations with the Plateau de Bure millimetre interferometer, operated by the Institute for Radio Astronomy in the Millimetre Range (IRAM), which is funded by a partnership of INSU/CNRS (France), MPG (Germany) and IGN (Spain).A FITS file for the spectrum

  17. Hot flue gas filtration: A new development

    SciTech Connect

    Levendis, Y.A.; Atal, A.

    1999-07-01

    A new development in the technology of flue gas filtration at high temperatures is introduced herein. In this technology the synergistic effects of sorbent injection and retention in a high-temperature filter/reactor are exploited. Calcium-based sorbents are sprayed in the post-combustion zone of a furnace. The sorbent reacts with sulfur and chlorine in the furnace effluent to form stable salts of calcium. The partially-reacted sorbent is then collected in the high-temperature filter, which is placed downstream of the sorbent injection point. The sorbent continues to react in the filter for a long period of time (minutes to a fraction of an hour), until the filter is regenerated. The primary advantage of this technique is both the likelihood and the duration of contact between the solid sorbent particles and the gaseous pollutants (such as SO{sub 2}, H{sub 2}S, HCI, etc.) increases, since reaction takes place both upstream of the filter as well as inside the filter itself. These emission reduction benefits may render medical waste incineration and municipal wastes-to-energy conversion acceptable to the public. Results from a series of preliminary laboratory tests are presented herein. These tests demonstrate the effectiveness of filter-sorbent combinations in enhancing the concentration reduction of SO{sub 2} and NO{sub x} emissions from combustion sources. Sorbent utilizations were enhanced by factors of 5 to 10, at the presence of the filter, and NO{sub x} reduction was mildly enhanced.

  18. Growth vs. Destruction of Interstellar Clouds in Hot Gas

    NASA Astrophysics Data System (ADS)

    Vieser, Wolfgang; Hensler, Gerhard

    The multi-phase interstellar medium (ISM) inherently bears the formation of interfaces between warm interstellar clouds and the hot, dilute gas phase that originates from supernova explosions. Physically the contact of the hot gas with a cool one at the surfaces of the clouds must lead to strong heat fluxes that tend to smear out the steep temperature discontinuity. The consequences of this heat conduction are manifold; two major effects are the following: firstly, it acts as a strong cooling agent of the hot gas, and secondly, the energy transport heats up the clouds and, depending on the physical state of the cloudy material, the cloud's surface evaporates or the cloud is able to get rid of the additional energy, cools, and accretes more surrounding gas. In order to investigate the possibilities mentioned above, we are performing 2D hydrodynamic simulations of molecular clouds in the flow of hot gas. Our models include self-gravity, heating and cooling effects and heat conduction by electrons. The thermal conductivity of a fully ionized hydrogen plasma is applied as well as a saturated heat flux in regions where the mean free path of the electrons is large compared to the temperature scaleheight. In this study the mass and size of the initial cloud and the density and temperature of the streaming ISM are varied. Comparison of the evaporation/condensation rates found for the different models with those predicted by Cowie & McKee (1977, ApJ 211, 135) shows significant differences: The numerical models reveal that condensation still occurs under circumstances where analytical results require the contrary. Consequences will be discussed.

  19. CHEMICALLY DISTINCT NUCLEI AND OUTFLOWING SHOCKED MOLECULAR GAS IN Arp 220

    SciTech Connect

    Tunnard, R.; Greve, T. R.; Garcia-Burillo, S.; Fuente, A.; Usero, A.; Planesas, P.; Carpio, J. Graciá; Hailey-Dunsheath, S.; Sturm, E.; Fischer, J.; González-Alfonso, E.; Neri, R.

    2015-02-10

    We present the results of interferometric spectral line observations of Arp 220 at 3.5 mm and 1.2 mm from the Plateau de Bure Interferometer, imaging the two nuclear disks in H{sup 13}CN(1-0) and (3-2), H{sup 13}CO{sup +}(1-0) and (3-2), and HN{sup 13}C(3-2) as well as SiO(2-1) and (6-5), HC{sup 15}N(3-2), and SO(6{sub 6}-5{sub 5}). The gas traced by SiO(6-5) has a complex and extended kinematic signature including a prominent P Cygni profile, almost identical to previous observations of HCO{sup +}(3-2). Spatial offsets 0.''1 north and south of the continuum center in the emission and absorption of the SiO(6-5) P Cygni profile in the western nucleus (WN) imply a bipolar outflow, delineating the northern and southern edges of its disk and suggesting a disk radius of ∼40 pc, consistent with that found by ALMA observations of Arp 220. We address the blending of SiO(6-5) and H{sup 13}CO{sup +}(3-2) by considering two limiting cases with regards to the H{sup 13}CO{sup +} emission throughout our analysis. Large velocity gradient modeling is used to constrain the physical conditions of the gas and to infer abundance ratios in the two nuclei. Our most conservative lower limit on the [H{sup 13}CN]/[H{sup 13}CO{sup +}] abundance ratio is 11 in the WN, compared with 0.10 in the eastern nucleus (EN). Comparing these ratios to the literature we argue on chemical grounds for an energetically significant active galactic nucleus in the WN driving either X-ray or shock chemistry, and a dominant starburst in the EN.

  20. Investigating the Origin of Hot Gas Lines in Herbig Ae/Be Stars

    NASA Astrophysics Data System (ADS)

    Cauley, P. Wilson; Johns-Krull, Christopher M.

    2016-07-01

    We analyze high-resolution UV spectra of a small sample of Herbig Ae/Be stars (HAEBESs) in order to explore the origin of the T ∼ 105 K gas in these stars. The C iv λ λ1548, 1550 line luminosities are compared to nonsimultaneous accretion rate estimates for the objects showing C iv emission. We show that the correlation between L C iv and \\dot{M} previously established for classical T Tauri stars (CTTSs) seems to extend into the HAEBE mass regime, although the large spread in literature \\dot{M} and A V values makes the actual relationship highly uncertain. With the exception of DX Cha, we find no evidence for hot, optically thick winds in our HAEBE sample. All other objects showing clear doublet emission in C iv can be well described by a two-component (i.e., a single component for each doublet member) or four-component (i.e., two components for each doublet member) Gaussian emission line fit. The morphologies and peak-flux velocities of these lines suggest that they are formed in weak, optically thin stellar winds and not in an accretion flow, as is the case for the hot lines observed in CTTSs. The lack of strong outflow signatures and lack of evidence for line formation in accretion flows are consistent with the conclusion presented in our recent optical and He i λ10830 studies that the immediate circumstellar environments of HAEBESs, in general, are not scaled-up analogs of the immediate environments around CTTSs. The conclusions presented here for hot gas lines around HAEBESs should be verified with a larger sample of objects.

  1. 30 CFR 77.303 - Hot gas inlet chamber dropout doors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet...

  2. 30 CFR 77.303 - Hot gas inlet chamber dropout doors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet...

  3. 30 CFR 77.303 - Hot gas inlet chamber dropout doors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet...

  4. 30 CFR 77.303 - Hot gas inlet chamber dropout doors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet...

  5. 30 CFR 77.303 - Hot gas inlet chamber dropout doors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet...

  6. Development of advanced hot-gas desulfurization sorbents. Final report

    SciTech Connect

    Jothimurugesan, K.; Adeyiga, A.A.; Gangwal, S.K.

    1997-10-01

    The objective of this project was to develop hot-gas desulfurization sorbent formulations for relatively lower temperature application, with emphasis on the temperature range from 343--538 C. The candidate sorbents include highly dispersed mixed metal oxides of zinc, iron, copper, cobalt, nickel and molybdenum. The specific objective was to develop suitable sorbents, that would have high and stable surface area and are sufficiently reactive and regenerable at the relatively lower temperatures of interest in this work. Stability of surface area during regeneration was achieved by adding stabilizers. To prevent sulfation, catalyst additives that promote the light-off of the regeneration reaction at lower temperature was considered. Another objective of this study was to develop attrition-resistant advanced hot-gas desulfurization sorbents which show stable and high sulfidation reactivity at 343 to 538 C and regenerability at lower temperatures than leading first generation sorbents.

  7. Calculations of hot gas ingestion for a STOVL aircraft model

    NASA Technical Reports Server (NTRS)

    Fricker, David M.; Holdeman, James D.; Vanka, Surya P.

    1992-01-01

    Hot gas ingestion problems for Short Take-Off, Vertical Landing (STOVL) aircraft are typically approached with empirical methods and experience. In this study, the hot gas environment around a STOVL aircraft was modeled as multiple jets in crossflow with inlet suction. The flow field was calculated with a Navier-Stokes, Reynolds-averaged, turbulent, 3D computational fluid dynamics code using a multigrid technique. A simple model of a STOVL aircraft with four choked jets at 1000 K was studied at various heights, headwind speeds, and thrust splay angles in a modest parametric study. Scientific visualization of the computed flow field shows a pair of vortices in front of the inlet. This and other qualitative aspects of the flow field agree well with experimental data.

  8. Durable zinc ferrite sorbent pellets for hot coal gas desulfurization

    DOEpatents

    Jha, Mahesh C.; Blandon, Antonio E.; Hepworth, Malcolm T.

    1988-01-01

    Durable, porous sulfur sorbents useful in removing hydrogen sulfide from hot coal gas are prepared by water pelletizing a mixture of fine zinc oxide and fine iron oxide with inorganic and organic binders and small amounts of activators such as sodium carbonate and molybdenite; the pellets are dried and then indurated at a high temperature, e.g., 1800.degree. C., for a time sufficient to produce crush-resistant pellets.

  9. Assessment of coal gasification/hot gas cleanup based advanced gas turbine systems

    SciTech Connect

    Not Available

    1990-12-01

    The major objectives of the joint SCS/DOE study of air-blown gasification power plants with hot gas cleanup are to: (1) Evaluate various power plant configurations to determine if an air-blown gasification-based power plant with hot gas cleanup can compete against pulverized coal with flue gas desulfurization for baseload expansion at Georgia Power Company's Plant Wansley; (2) determine if air-blown gasification with hot gas cleanup is more cost effective than oxygen-blown IGCC with cold gas cleanup; (3) perform Second-Law/Thermoeconomic Analysis of air-blown IGCC with hot gas cleanup and oxygen-blown IGCC with cold gas cleanup; (4) compare cost, performance, and reliability of IGCC based on industrial gas turbines and ISTIG power island configurations based on aeroderivative gas turbines; (5) compare cost, performance, and reliability of large (400 MW) and small (100 to 200 MW) gasification power plants; and (6) compare cost, performance, and reliability of air-blown gasification power plants using fluidized-bed gasifiers to air-blown IGCC using transport gasification and pressurized combustion.

  10. Strength testing of hot gas filters: Volume 6. Final report

    SciTech Connect

    Faber, K.T.

    1998-06-09

    The strength of various ceramic hot gas filter materials has been evaluated by four laboratories: Argonne National Laboratory, DuPont Lanxide, Southern Research Institute and Babcock and Wilcox. The filter materials under study include (a) a Nextel{trademark}/SiC composite filter (from 3M), (b) PRD-66, an all oxide layered microstructure of alumina, mullite, cordierite and some amorphous material by DuPont Lanxide, (c) a Babcock and Wilcox material consisting of an oxide composite of chopped fibers (Saffil) and continuous Nextel fibers, (d-f) monolithic and recrystallized SiC materials and an alumino/aluminosilicate material by IFPM, and (g) a monolithic SiC by the Pall Corporation. Not all four organizations tested each of the materials. PRD-66 was tested by three of the four. Four tests were used to evaluate properties of the candle filter materials. They included (a) the C-ring test, (b) the O-ring test, (c) the burst test and (d) the axial compression test. Each organization identified above did not perform all four tests. The objective of the study described here was to (a) provide an evaluation of the test methods used for hot gas filters to determine which is best for hot gas filter evaluation and (b) evaluate the discrepancies in results from tests run at different laboratories. No material ranking was made here, nor requested.

  11. Hot Gas and AGN Feedback in Galaxies and Nearby Groups

    NASA Astrophysics Data System (ADS)

    Jones, Christine; Forman, William; Bogdan, Akos; Randall, Scott; Kraft, Ralph; Churazov, Eugene

    2013-07-01

    Massive galaxies harbor a supermassive black hole at their centers. At high redshifts, these galaxies experienced a very active quasar phase, when, as their black holes grew by accretion, they produced enormous amounts of energy. At the present epoch, these black holes still undergo occasional outbursts, although the mode of their energy release is primarily mechanical rather than radiative. The energy from these outbursts can reheat the cooling gas in the galaxy cores and maintain the red and dead nature of the early-type galaxies. These outbursts also can have dramatic effects on the galaxy-scale hot coronae found in the more massive galaxies. We describe research in three areas related to the hot gas around galaxies and their supermassive black holes. First we present examples of galaxies with AGN outbursts that have been studied in detail. Second, we show that X-ray emitting low-luminosity AGN are present in 80% of the galaxies studied. Third, we discuss the first examples of extensive hot gas and dark matter halos in optically faint galaxies.

  12. Tidd hot gas clean up program. Final report

    SciTech Connect

    1995-10-01

    This Final Report on the Tidd Hot Gas Clean Up Program covers the period from initial Proof-of-Concept testing in August, 1990, through final equipment inspections in May, 1995. The Tidd Hot Gas Clean Up (HGCU) system was installed in the Tidd Pressurized Fluidized Bed Combustion (PFBC) Demonstration Plant, which is the first utility-scale PFBC plant in the United States. Detailed design work on the project began in July, 1990, and site construction began in December, 1991. Initial operation of the system occurred in May, 1992, and the hot gas filter was commissioned in October, 1992. The test program ended in March, 1995, when the Tidd Plant was shut down following its four-year test program. Section 1.0 of this report is an executive summary of the project covering the project background, system description, test results and conclusions. Section 2.0 is an introduction covering the program objectives and schedule. Section 3.0 provides detailed descriptions of the system and its major components. Section 4.0 provides detailed results of all testing including observations and posttest inspection results. Sections 5.0 and 6.0 list the program conclusions and recommendations, respectively. Appendix I is a report prepared by Southern Research Institute on the properties of Tidd PFBC ash sampled during the test program. Appendix II is a report prepared by Westinghouse STC on the performance of candle filter fail-safe regenerator devices.

  13. Ceramem filters for removal of particles from hot gas streams

    SciTech Connect

    Bishop, B.A.; Goldsmith, R.L.

    1994-11-01

    The need for hot gas cleanup in the power, advanced coal conversion, process and incineration industries is well documented and extensive development is being undertaken to develop and demonstrate suitable filtration technologies. In general, process conditions include (a) oxidizing or reducing atmospheres, (b) temperatures to 1800{degree}F, (c) pressures to 300 psi, and (d) potentially corrosive components in the gas stream. The most developed technologies entail the use of candle or tube filters, which suffer from fragility, lack of oxidation/corrosion resistance, and high cost. The ceramic membrane filter described below offers the potential to eliminate these limitations.

  14. Improving hot gas filtration behavior in PFBC power plants

    SciTech Connect

    Romeo, L.M.; Gil, A.; Cortes, C.

    1999-07-01

    According to a previous paper, a laboratory-scale cold flow model of the hot gas filtration system in Escatron PFBC power plant has been built. The main objectives were to establish the validity of the scaling laws for cyclone separator systems (cyclone and dipleg) and to perform detailed room temperature studies in a rapid and cost effective manner. In Escatron PFBC power plant, the hot gas filtration equipment is a two-stage process performed in nine streams between the fluidized bed and the gas turbine. Due to the unsteadiness in the dipleg and the suction nozzle, and the effect of sintered deposit, the cyclone performance is modified. The performances of cyclone separator system and suction nozzle diplegs are scarcely reported in the open literature. This paper presents the results of a detailed research in which some important conclusions of well known studies about cyclones are verified. Also remarkable is the increase in cyclone efficiency and decrease in pressure drop when the solid load to the cyclone is increased. The possibility to check the fouling by means of pressure drop has not been previously addressed. Finally, the influences of gas input velocity to the cyclone, the transport gas to the ash conveying lines, the solid load and the cyclone fouling have been analyzed. This study has allowed characterizing the performance of the full-scale ash removal system, establishing safe limits of operation and testing design improvements as the two suction nozzle dipleg, pointing out important conclusions for the filtration process in PFBC power plants.

  15. BENCH-SCALE DEMONSTRATION OF HOT-GAS DESULFURIZATION TECHNOLOGY

    SciTech Connect

    Unknown

    1999-10-01

    The U.S. Department of Energy (DOE), Federal Energy Technology Center (FETC), is sponsoring research in advanced methods for controlling contaminants in hot coal gasifier gas (coal-derived fuel-gas) streams of integrated gasification combined-cycle (IGCC) power systems. The hot gas cleanup work seeks to eliminate the need for expensive heat recovery equipment, reduce efficiency losses due to quenching, and minimize wastewater treatment costs. Hot-gas desulfurization research has focused on regenerable mixed-metal oxide sorbents that can reduce the sulfur in coal-derived fuel-gas to less than 20 ppmv and can be regenerated in a cyclic manner with air for multicycle operation. Zinc titanate (Zn{sub 2} TiO{sub 4} or ZnTiO{sub 3}), formed by a solid-state reaction of zinc oxide (ZnO) and titanium dioxide (TiO{sub 2}), is currently one of the leading sorbents. Overall chemical reactions with Zn{sub 2} TiO{sub 4} during the desulfurization (sulfidation)-regeneration cycle are shown below: Sulfidation: Zn{sub 2} TiO{sub 4} + 2H{sub 2}S {yields} 2ZnS + TiO{sub 2} + 2H{sub 2}O; Regeneration: 2ZnS + TiO{sub 2} + 3O{sub 2} {yields} Zn{sub 2} TiO{sub 4} + 2SO{sub 2} The sulfidation/regeneration cycle can be carried out in a fixed-bed, moving-bed, or fluidized-bed reactor configuration. The fluidized-bed reactor configuration is most attractive because of several potential advantages including faster kinetics and the ability to handle the highly exothermic regeneration to produce a regeneration offgas containing a constant concentration of SO{sub 2}.

  16. Descriptions of the neutral gas outflow in Comets P/Halley and Wilson (1987 VII) from analyses of velocity-resolved H2O line profiles

    NASA Technical Reports Server (NTRS)

    Larson, Harold P.; Hu, Hong-Yao; Hsieh, K. C.; Weaver, Harold A.; Mumma, Michael J.

    1991-01-01

    The spatial distribution and expansion velocity of the Comets Wilson (1987 VII) and pre- and postperihelion P/Halley are derived on the bases of velocity-resolved H2O spectral line profiles, using a kinematic model which synthesizes line profiles for comparison with observed line shapes. The results thus obtained demonstrate that the spherically symmetric outflow at constant velocity is a poor characterization of cometary neutral-gas outflow. While the radial dependence of the H2O expansion velocity is noted to be consistent with theoretically envisioned trends, the high H2O outflow velocity observed in Comet Wilson resists reconciliation with any existing kinematic model.

  17. Water and methanol in low-mass protostellar outflows: gas-phase synthesis, ice sputtering and destruction

    NASA Astrophysics Data System (ADS)

    Suutarinen, A. N.; Kristensen, L. E.; Mottram, J. C.; Fraser, H. J.; van Dishoeck, E. F.

    2014-05-01

    Water in outflows from protostars originates either as a result of gas-phase synthesis from atomic oxygen at T ≳ 200 K, or from sputtered ice mantles containing water ice. We aim to quantify the contribution of the two mechanisms that lead to water in outflows, by comparing observations of gas-phase water to methanol (a grain surface product) towards three low-mass protostars in NGC 1333. In doing so, we also quantify the amount of methanol destroyed in outflows. To do this, we make use of James Clerk Maxwell Telescope and Herschel-Heterodyne Instrument for the Far-Infrared data of H2O, CH3OH and CO emission lines and compare them to RADEX non-local thermodynamic equilibrium excitation simulations. We find up to one order of magnitude decrease in the column density ratio of CH3OH over H2O as the velocity increases in the line wings up to ˜15 km s-1. An independent decrease in X(CH3OH) with respect to CO of up to one order of magnitude is also found in these objects. We conclude that gas-phase formation of H2O must be active at high velocities (above 10 km s-1 relative to the source velocity) to re-form the water destroyed during sputtering. In addition, the transition from sputtered water at low velocities to form water at high velocities must be gradual. We place an upper limit of two orders of magnitude on the destruction of methanol by sputtering effects.

  18. The onset of Wolf-Rayet wind outflow and the nature of the hot component in the symbiotic nova PU Vulpecula

    NASA Technical Reports Server (NTRS)

    Sion, Edward M.; Shore, Steven N.; Ready, Christian J.; Scheible, Maureen P.

    1993-01-01

    We have analyzed temporal variations in the far ultraviolet He II (1640), Si IV (1393, 1402), and C IV (1548, 1550) line profiles in eight high dispersion, International Ultraviolet Explorer Short Wavelength Prime spectra of the symbiotic nova PU Vul by comparatively examining these profiles on a common velocity scale. We see clear evidence of the onset of a Wolf-Rayet-like wind outflow from the bloated, contracting white dwarf hot component with terminal velocity of approximately equals -550 to -600 km/s. We have quantitatively analyzed the complicated He II (1640) emission region for the first time and show that the discrete absorption features seen in the He II region occur at precisely the same velocites in each spectrum, thus demonstrating that the absorbing source is steady and not affected by any orbital motion. We demonstrate that there is an underlying He II wind emission feature whose true shape is hidden by superposed absorption due to the foreground red giant wind flowing in front of the white dwarf and abscuring the white dwarf's wind outflow. We present synthetic spectra of He II emission behind an absorbing slab with u = 20 km/s, T = 5000 K, and column densities in the range N = 1 x 10(exp 22) and 1 x 10(exp 23)/sq cm which explain these absorptions. Our analysis of the Si IV and C IV resonance doublets, in velocity space, reveal temporal variations in the profile between 1987 and 1991 with the emergence of clear P Cygni profiles in Si IV by 1990. A nebular emission feature in C III 1909 also appears in the most recent spectra (e.g., SW42538H) while it was absent or extremely weak in the earliest spectra (e.g., SW36332H), thus strengthening evidence that the nebular emission, as seen in permitted and semiforbidden lines, intensities in step with the onset of the hot, fast, wind outflow. We also report the first detection of narrow interstellar (circumbinary shell?) absorption lines near -1 km/s, most strongly in Al III (1854, 1862) and Si IV (1392

  19. Sublimating comets as the source of nucleation seeds for grain condensation in the gas outflow from AGB stars

    NASA Technical Reports Server (NTRS)

    Whitmire, D. P.; Matese, John J.; Reynolds, R. T.

    1989-01-01

    A growing amount of observational and theoretical evidence suggests that most main sequence stars are surrounded by disks of cometary material. The dust production by comets in such disks is investigated when the central stars evolve up the red giant and asymptotic giant branch (AGB). Once released, the dust is ablated and accelerated by the gas outflow and the fragments become the seeds necessary for condensation of the gas. The origin of the requisite seeds has presented a well known problem for classical nucleation theory. This model is consistent with the dust production observed in M giants and supergiants (which have increasing luminosities) and the fact that earlier supergiants and most WR stars (whose luminosities are unchanging) do not have significant dust clouds even though they have significant stellar winds. Another consequence of the model is that the spatial distribution of the dust does not, in general, coincide with that of the gas outflow, in contrast to the conventional condensation model. A further prediction is that the condensation radius is greater that that predicted by conventional theory which is in agreement with IR interferometry measurements of alpha-Ori.

  20. Production of light oil by injection of hot inert gas

    NASA Astrophysics Data System (ADS)

    Ruidas, Bidhan C.; Ganguly, Somenath

    2016-05-01

    Hot inert gas, when injected into an oil reservoir is capable of generating a vaporization-condensation drive and as a consequence, a preferential movement of the lighter components to the production well. This form of displacement is an important unit mechanism in hot flue-gas injection, or in thermal recovery from a watered-out oil reservoir. This article presents the movement of heat front vis-à-vis the changes in the saturation profile, and the gas-phase composition. The plateau in the temperature profile due to the exchange of latent heat, and the formation of water bank at the downstream are elaborated. The broadening of the vaporization-condensation zone with continued progression is discussed. The effect of inert gas temperature on the cumulative production of oil is reviewed. The results provide insight to the vaporization-condensation drive as a stand-alone mechanism. The paper underscores the relative importance of this mechanism, when operated in tandem with other processes in improved oil recovery and CO2 sequestration.

  1. The Rotation of the Hot Gas around the Milky Way

    NASA Astrophysics Data System (ADS)

    Hodges-Kluck, Edmund J.; Miller, Matthew J.; Bregman, Joel N.

    2016-05-01

    The hot gaseous halos of galaxies likely contain a large amount of mass and are an integral part of galaxy formation and evolution. The Milky Way has a 2× {10}6 K halo that is detected in emission and by absorption in the O vii resonance line against bright background active galactic nuclei (AGNs), and for which the best current model is an extended spherical distribution. Using XMM-Newton Reflection Grating Spectrometer data, we measure the Doppler shifts of the O vii absorption-line centroids toward an ensemble of AGNs. These Doppler shifts constrain the dynamics of the hot halo, ruling out a stationary halo at about 3σ and a co-rotating halo at 2σ , and leading to a best-fit rotational velocity of {v}φ =183+/- 41 km s‑1 for an extended halo model. These results suggest that the hot gas rotates and that it contains an amount of angular momentum comparable to that in the stellar disk. We examined the possibility of a model with a kinematically distinct disk and spherical halo. To be consistent with the emission-line X-ray data, the disk must contribute less than 10% of the column density, implying that the Doppler shifts probe motion in the extended hot halo.

  2. Global Hot Gas in and around the Galaxy

    NASA Astrophysics Data System (ADS)

    Wang, Q. Daniel

    2009-08-01

    The hot interstellar medium traces the stellar feedback and its role in regulating the eco-system of the Galaxy. I review recent progress in understanding the medium, based largely on X-ray absorption line spectroscopy, complemented by X-ray emission and far-UV O VI absorption measurements. These observations enable us for the first time to characterize the global spatial, thermal, chemical, and kinematic properties of the medium. The results are generally consistent with what have been inferred from X-ray imaging of nearby galaxies similar to the Galaxy. It is clear that diffuse soft X-ray emitting/absorbing gas with a characteristic temperature of ~106 K resides primarily in and around the Galactic disk and bulge. In the solar neighborhood, for example, this gas has a characteristic vertical scale height of ~1 kpc. This conclusion does not exclude the presence of a larger-scale, probably much hotter, and lower density circum-Galactic hot medium, which is required to explain observations of various high-velocity clouds. This hot medium may be a natural product of the stellar feedback in the context of the galaxy formation and evolution.

  3. Apparatus for hot-gas desulfurization of fuel gases

    DOEpatents

    Bissett, Larry A.

    1992-01-01

    An apparatus for removing sulfur values from a hot fuel gas stream in a fdized bed contactor containing particulate sorbent material by employing a riser tube regeneration arrangement. Sulfur-laden sorbent is continuously removed from the fluidized bed through a stand pipe to the riser tube and is rapidly regenerated in the riser tube during transport of the sorbent therethrough by employing an oxygen-containing sorbent regenerating gas stream. The riser tube extends from a location below the fluidized bed to an elevation above the fluidized bed where a gas-solid separating mechanism is utilized to separate the regenerated particulate sorbent from the regeneration gases and reaction gases so that the regenerated sorbent can be returned to the fluidized bed for reuse.

  4. Characterization of Field-Exposed Iron Aluminide Hot Gas Filters

    SciTech Connect

    McKamey, C.G.; McCleary, D.; Tortorelli, P.F.; Sawyer, J.; Lara-Curzio, E.; Judkins, R.R.

    2002-09-19

    The use of a power turbine fired with coal-derived synthesis gas will require some form of gas cleaning in order to protect turbine and downstream components from degradation by erosion, corrosion, or deposition. Hot-gas filtration is one form of cleaning that offers the ability to remove particles from the gases produced by gasification processes without having to substantially cool and, possibly, reheat them before their introduction into the turbine. This technology depends critically on materials durability and reliability, which have been the subject of study for a number of years (see, for example, Alvin 1997, Nieminen et al. 1996, Oakey et al. 1997, Quick and Weber 1995, Tortorelli, et al. 1999).

  5. DEMOGRAPHICS AND PHYSICAL PROPERTIES OF GAS OUTFLOWS/INFLOWS AT 0.4 < z < 1.4

    SciTech Connect

    Martin, Crystal L.; Shapley, Alice E.; Kornei, Katherine A.; Coil, Alison L.; Bundy, Kevin; Weiner, Benjamin J.; Noeske, Kai G.; Schiminovich, David

    2012-12-01

    We present Keck/LRIS spectra of over 200 galaxies with well-determined redshifts between 0.4 and 1.4. We combine new measurements of near-ultraviolet, low-ionization absorption lines with previously measured masses, luminosities, colors, and star formation rates to describe the demographics and properties of galactic flows. Among star-forming galaxies with blue colors, we find a net blueshift of the Fe II absorption greater than 200 km s{sup -1} (100 km s{sup -1}) toward 2.5% (20%) of the galaxies. The fraction of blueshifted spectra does not vary significantly with stellar mass, color, or luminosity but does decline at specific star formation rates less than roughly 0.8 Gyr{sup -1}. The insensitivity of the blueshifted fraction to galaxy properties requires collimated outflows at these redshifts, while the decline in outflow fraction with increasing blueshift might reflect the angular dependence of the outflow velocity. The low detection rate of infalling gas, 3%-6% of the spectra, suggests an origin in (enriched) streams favorably aligned with our sightline. We find that four of these nine infalling streams have projected velocities commensurate with the kinematics of an extended disk or satellite galaxy. The strength of the Mg II absorption increases with stellar mass, B-band luminosity, and U - B color, trends arising from a combination of more interstellar absorption at the systemic velocity and less emission filling in more massive galaxies. Our results provide a new quantitative understanding of gas flows between galaxies and the circumgalactic medium over a critical period in galaxy evolution.

  6. Sgr A* and Its Environment: Low-mass Star Formation, the Origin of X-Ray Gas and Collimated Outflow

    NASA Astrophysics Data System (ADS)

    Yusef-Zadeh, F.; Wardle, M.; Schödel, R.; Roberts, D. A.; Cotton, W.; Bushouse, H.; Arendt, R.; Royster, M.

    2016-03-01

    We present high-resolution multiwavelength radio continuum images of the region within 150″ of Sgr A*, revealing a number of new extended features and stellar sources in this region. First, we detect a continuous 2″ east-west ridge of radio emission, linking Sgr A* and a cluster of stars associated with IRS 13 N and IRS 13E. The ridge suggests that an outflow of east-west blob-like structures is emerging from Sgr A*. In particular, we find arc-like radio structures within the ridge with morphologies suggestive of photoevaporative protoplanetary disks. We use infrared Ks and L‧ fluxes to show that the emission has similar characteristics to those of a protoplanetary disk irradiated by the intense radiation field at the Galactic center. This suggests that star formation has taken place within the S-cluster 2″ from Sgr A*. We suggest that the diffuse X-ray emission associated with Sgr A* is due to an expanding hot wind produced by the mass loss from B-type main sequence stars, and/or the disks of photoevaporation of low mass young stellar objects (YSOs) at a rate of ˜10-6 {M}⊙ yr-1. The proposed model naturally reduces the inferred accretion rate and is an alternative to the inflow-outflow style models to explain the underluminous nature of Sgr A*. Second, on a scale of 5″ from Sgr A*, we detect new cometary radio and infrared sources at a position angle PA ˜ 50° which is similar to that of two other cometary sources X3 and X7, all of which face Sgr A*. In addition, we detect a striking tower of radio emission at a PA ˜ 50°-60° along the major axis of the Sgr A East supernova remnant shell on a scale of 150″ from Sgr A*. We suggest that the cometary sources and the tower feature are tracing interaction sites of a mildly relativistic jet from Sgr A* with the atmosphere of stars and the nonthermal Sgr A East shell at a PA ˜ 50°-60° with \\dot{M}˜ 1× {10}-7 {M}⊙ {{yr}}-1, and opening angle 10°. Lastly, we suggest that the east-west ridge of

  7. Advances in Ammonia Removal from Hot Coal Gas

    SciTech Connect

    Jothimurugesan, K.; Gangwal, S.K.

    1996-12-31

    Nitrogen occurs in coal in the form of tightly bound organic ring compounds, typically at levels of 1 to 2 wt%. During coal gasification, this fuel bound nitrogen is released principally as ammonia (NH{sub 3}). When hot coal gas is used to generate electricity in integrated gasification combined cycle (IGCC) power plants, NH{sub 3} is converted to nitrogen oxides (NO{sub x}) which are difficult to remove and are highly undesirable as atmospheric pollutants. Similarly, while the efficiency of integrated gasification molten carbonate fuel cell (IGFC) power plants is not affected by NH{sub 3}, NO{sub x} is generated during combustion of the anode exhaust gas. Thus NH{sub 3} must be removed from hot coal gas before it can be burned in a turbine or fuel cell. The objective of this study is to develop a successful combination of an NH{sub 3} decomposition catalyst with a zinc-based mixed-metal oxide sorbent so that the sorbent-catalyst activity remains stable for NH{sub 3} decomposition in addition to H{sub 2}S removal under cycle sulfidation-regeneration conditions in the temperature range of 500 to 750{degrees}C.

  8. Small-scale AFBC hot air gas turbine power cycle

    SciTech Connect

    Ashworth, R.A.; Keener, H.M.; Hall, A.W.

    1995-12-31

    The Energy and Environmental Research Corporation (EER), the Ohio Agricultural Research and Development Center (OARDC), the Will-Burt Company (W-B) and the US Department of Energy (DOE) have successfully developed and completed pilot plant tests on a small scale atmospheric fluidized bed combustion (AFBC) system. This system can be used to generate electricity, and/or hot water, steam. Following successful pilot plant operation, commercial demonstration will take place at Cedar Lane Farms (CLF), near Wooster, Ohio. The system demonstration will be completed by the end of 1995. The project is being funded through a cooperative effort between the DOE, EER, W-B, OARDC, CLF and the Ohio Coal Development Office (OCDO). The small scale AFBC, has no internal heat transfer surfaces in the fluid bed proper. Combining the combustor with a hot air gas turbine (HAGT) for electrical power generation, can give a relatively high overall system thermal efficiency. Using a novel method of recovering waste heat from the gas turbine, a gross heat rate of 13,500 Btu/kWhr ({approximately}25% efficiency) can be achieved for a small 1.5 MW{sub e} plant. A low technology industrial recuperation type gas turbine is used that operates with an inlet blade temperature of 1,450 F and a compression ratio of 3.9:1. The AFBC-HAGT technology can be used to generate power for remote rural communities to replace diesel generators, or can be used for small industrial co-generation applications.

  9. Development of NDE methods for hot gas filters.

    SciTech Connect

    Deemer, C.; Ellingson, W. A.; Koehl, E. R.; Lee, H.; Spohnholtz, T.; Sun, J. G.

    1999-07-21

    Ceramic hot gas candle filters are currently under development for hot gas particulate cleanup in advanced coal-based power systems. The ceramic materials for these filters include nonoxide monolithic, nonoxide-fiber-reinforced composites, and nonoxide reticulated foam. A concern is the lack of reliable data on which to base decisions for reusing or replacing hot gas filters during plant shutdowns. The work in this project is aimed at developing nondestructive evaluation (FIDE) technology to allow detection, and determination of extent, of life-limiting characteristics such as thermal fatigue, oxidation, damage from ash bridging such as localized cracking, damage from local burning, and elongation at elevated temperature. Although in-situ NDE methods are desirable in order to avoid disassembly of the candle filter vessels, the current vessel designs, the presence of filter cakes and possible ash bridging, and the state of NDE technology prevent this. Candle filter producers use a variety of NDE methods to ensure as-produced quality. While impact acoustic resonance offers initial promise for examining new as-produced filters and for detecting damage in some monolithic filters when removed from service, it presents difficulties in data interpretation, it lacks localization capability, and its applicability to composites has yet to be demonstrated. Additional NDE technologies being developed and evaluated in this program and whose applicability to both monolithics and composites has been demonstrated include (a) full-scale thermal imaging for analyzing thermal property variations; (b) fret, high-spatial-resolution X-ray imaging for detecting density variations and dimensional changes; (c) air-coupled ultrasonic methods for determining through-thickness compositional variations; and (d) acoustic emission technology with mechanical loading for detecting localized bulk damage. New and exposed clay-bonded SiC filters and CVI-SiC composite filters have been tested with

  10. Advanced hot gas cleaning system for coal gasification processes

    NASA Astrophysics Data System (ADS)

    Newby, R. A.; Bannister, R. L.

    1994-04-01

    The United States electric industry is entering a period where growth and the aging of existing plants will mandate a decision on whether to repower, add capacity, or do both. The power generation cycle of choice, today, is the combined cycle that utilizes the Brayton and Rankine cycles. The combustion turbine in a combined cycle can be used in a repowering mode or in a greenfield plant installation. Today's fuel of choice for new combined cycle power generation is natural gas. However, due to a 300-year supply of coal within the United States, the fuel of the future will include coal. Westinghouse has supported the development of coal-fueled gas turbine technology over the past thirty years. Working with the U.S. Department of Energy and other organizations, Westinghouse is actively pursuing the development and commercialization of several coal-fueled processes. To protect the combustion turbine and environment from emissions generated during coal conversion (gasification/combustion) a gas cleanup system must be used. This paper reports on the status of fuel gas cleaning technology and describes the Westinghouse approach to developing an advanced hot gas cleaning system that contains component systems that remove particulate, sulfur, and alkali vapors. The basic process uses ceramic barrier filters for multiple cleaning functions.

  11. NIHAO IX: the role of gas inflows and outflows in driving the contraction and expansion of cold dark matter haloes

    NASA Astrophysics Data System (ADS)

    Dutton, Aaron A.; Macciò, Andrea V.; Dekel, Avishai; Wang, Liang; Stinson, Gregory; Obreja, Aura; Di Cintio, Arianna; Brook, Chris; Buck, Tobias; Kang, Xi

    2016-09-01

    We use ˜100 cosmological galaxy formation `zoom-in' simulations using the smoothed particle hydrodynamics code GASOLINE to study the effect of baryonic processes on the mass profiles of cold dark matter haloes. The haloes in our study range from dwarf (M200 ˜ 1010 M⊙) to Milky Way (M200 ˜ 1012 M⊙) masses. Our simulations exhibit a wide range of halo responses, primarily varying with mass, from expansion to contraction, with up to factor ˜10 changes in the enclosed dark matter mass at 1 per cent of the virial radius. Confirming previous studies, the halo response is correlated with the integrated efficiency of star formation: ɛSF ≡ (Mstar/M200)/(Ωb/Ωm). In addition, we report a new correlation with the compactness of the stellar system: ɛR ≡ r1/2/R200. We provide an analytic formula depending on ɛSF and ɛR for the response of cold dark matter haloes to baryonic processes. An observationally testable prediction is that, at fixed mass, larger galaxies experience more halo expansion, while the smaller galaxies more halo contraction. This diversity of dark halo response is captured by a toy model consisting of cycles of adiabatic inflow (causing contraction) and impulsive gas outflow (causing expansion). For net outflow, or equal inflow and outflow fractions, f, the overall effect is expansion, with more expansion with larger f. For net inflow, contraction occurs for small f (large radii), while expansion occurs for large f (small radii), recovering the phenomenology seen in our simulations. These regularities in the galaxy formation process provide a step towards a fully predictive model for the structure of cold dark matter haloes.

  12. Numerical Investigation of Hot Gas Ingestion by STOVL Aircraft

    NASA Technical Reports Server (NTRS)

    Vanka, S. P.

    1998-01-01

    This report compiles the various research activities conducted under the auspices of the NASA Grant NAG3-1026, "Numerical Investigation of Hot Gas Ingestion by STOVL Aircraft" during the period of April 1989 to April 1994. The effort involved the development of multigrid based algorithms and computer programs for the calculation of the flow and temperature fields generated by Short Take-off and Vertical Landing (STOVL) aircraft, while hovering in ground proximity. Of particular importance has been the interaction of the exhaust jets with the head wind which gives rise to the hot gas ingestion process. The objective of new STOVL designs to reduce the temperature of the gases ingested into the engine. The present work describes a solution algorithm for the multi-dimensional elliptic partial-differential equations governing fluid flow and heat transfer in general curvilinear coordinates. The solution algorithm is based on the multigrid technique which obtains rapid convergence of the iterative numerical procedure for the discrete equations. Initial efforts were concerned with the solution of the Cartesian form of the equations. This algorithm was applied to a simulated STOVL configuration in rectangular coordinates. In the next phase of the work, a computer code for general curvilinear coordinates was constructed. This was applied to model STOVL geometries on curvilinear grids. The code was also validated in model problems. In all these efforts, the standard k-Epsilon model was used.

  13. Toward the Active Control of Heat Transfer in the Hot Gas Path of Gas Turbines

    NASA Technical Reports Server (NTRS)

    Oertling, Jeremiah E.

    2003-01-01

    The work at NASA this summer has focused on assisting the Professor's project, namely "Toward the Active Control of Heat Transfer in the Hot Gas Path of Gas Turbines." The mode of controlling the Heat Transfer that the project focuses on is film cooling. Film cooling is used in high temperature regions of a gas turbine and extends the life of the components exposed to these extreme temperatures. A "cool" jet of air is injected along the surface of the blade and this layer of cool air shields the blade from the high temperatures. Cool is a relative term. The hot gas path temperatures reach on the order of 1500 to 2000 K. The "coo" air is on the order of 700 to 1000 K. This cooler air is bled off of an appropriate compressor stage. The next parameter of interest is the jet s position and orientation in the flow-field.

  14. METC integrated bench scale gasification and hot gas cleanup studies

    SciTech Connect

    Rockey, J.M.; Kanosky, J.P.; Rutten, J.

    1992-11-01

    The cleanup test section consists of a closely coupled modular gas cleanup rig (MGCR) which was acquired from The Institute of Gas Technology. The MGCR receives coal-derived gas at 425 psig and 1,000{degrees}F from the METC Fluid-Bed Gasifier. The gas pressure is reduced to approximately 300 psia, reheated to 1,200{degrees}F, and filtered by a candle filter vessel containing up to four filter cartridges. For batch-mode test operations, the filtered coal gas is fed into a 6-inch ID, fluid-bed reactor that is preloaded with desulfurization sorbent. Batch-mode sulfidation tests demonstrated that the prospects for developing an effective fluid-bed hot-gas desulfurization system are promising, since H{sub 2}S removal of greater than 99 percent was consistently shown with sorbent utilization up to 25 percent. Conversely, the regeneration conducted in the batch mode MGCR was not useful because the regeneration occurs too quickly, and thus process concerns cannot be suitably evaluated in the batch fluid-bed mode reactor. Pursuant to batch mode tests, the gas cleanup system is being modified to incorporate a reactor in parallel with the batch reactor so that solids can be fed into and withdrawn from the reactor without impacting batch mode operation in the meantime. The new reactor setup which allows for through-flow of solid sorbent during operation is also being designed to operate using smaller (70--150 micron) particles in addition to the larger (200--300 micron) particles used in prior tests.

  15. METC integrated bench scale gasification and hot gas cleanup studies

    SciTech Connect

    Rockey, J.M.; Kanosky, J.P. ); Rutten, J. )

    1992-01-01

    The cleanup test section consists of a closely coupled modular gas cleanup rig (MGCR) which was acquired from The Institute of Gas Technology. The MGCR receives coal-derived gas at 425 psig and 1,000[degrees]F from the METC Fluid-Bed Gasifier. The gas pressure is reduced to approximately 300 psia, reheated to 1,200[degrees]F, and filtered by a candle filter vessel containing up to four filter cartridges. For batch-mode test operations, the filtered coal gas is fed into a 6-inch ID, fluid-bed reactor that is preloaded with desulfurization sorbent. Batch-mode sulfidation tests demonstrated that the prospects for developing an effective fluid-bed hot-gas desulfurization system are promising, since H[sub 2]S removal of greater than 99 percent was consistently shown with sorbent utilization up to 25 percent. Conversely, the regeneration conducted in the batch mode MGCR was not useful because the regeneration occurs too quickly, and thus process concerns cannot be suitably evaluated in the batch fluid-bed mode reactor. Pursuant to batch mode tests, the gas cleanup system is being modified to incorporate a reactor in parallel with the batch reactor so that solids can be fed into and withdrawn from the reactor without impacting batch mode operation in the meantime. The new reactor setup which allows for through-flow of solid sorbent during operation is also being designed to operate using smaller (70--150 micron) particles in addition to the larger (200--300 micron) particles used in prior tests.

  16. Development of advanced hot-gas desulfurization processes

    SciTech Connect

    Jothimurugesan, K.

    1999-10-14

    Advanced integrated gasification combined cycle (IGCC) power plants nearing completion, such as Sierra-Pacific, employ a circulating fluidized-bed (transport) reactor hot-gas desulfurization (HGD) process that uses 70-180 {micro}m average particle size (aps) zinc-based mixed-metal oxide sorbent for removing H{sub 2}S from coal gas down to less than 20 ppmv. The sorbent undergoes cycles of absorption (sulfidation) and air regeneration. The key barrier issues associated with a fluidized-bed HGD process are chemical degradation, physical attrition, high regeneration light-off (initiation) temperature, and high cost of the sorbent. Another inherent complication in all air-regeneration-based HGD processes is the disposal of the problematic dilute SO{sub 2} containing regeneration tail-gas. Direct Sulfur Recovery Process (DSRP), a leading first generation technology, efficiently reduces this SO{sub 2} to desirable elemental sulfur, but requires the use of 1-3 % of the coal gas, thus resulting in an energy penalty to the plant. Advanced second-generation processes are under development that can reduce this energy penalty by modifying the sorbent so that it could be directly regenerated to elemental sulfur. The objective of this research is to support the near and long term DOE efforts to commercialize the IGCC-HGD process technology. Specifically we aim to develop: optimized low-cost sorbent materials with 70-80 {micro}m average aps meeting all Sierra specs; attrition resistant sorbents with 170 {micro}m aps that allow greater flexibility in the choice of the type of fluidized-bed reactor e.g. they allow increased throughput in a bubbling-bed reactor; and modified fluidizable sorbent materials that can be regenerated to produce elemental sulfur directly with minimal or no use of coal gas The effort during the reporting period has been devoted to development of an advanced hot-gas process that can eliminate the problematic SO{sub 2} tail gas and yield elemental sulfur

  17. Ceramic Composite Development for Gas Turbine Engine Hot Section Components

    NASA Technical Reports Server (NTRS)

    DiCarlo, James A.; VANrOODE, mARK

    2006-01-01

    The development of ceramic materials for incorporation into the hot section of gas turbine engines has been ongoing for about fifty years. Researchers have designed, developed, and tested ceramic gas turbine components in rigs and engines for automotive, aero-propulsion, industrial, and utility power applications. Today, primarily because of materials limitations and/or economic factors, major challenges still remain for the implementation of ceramic components in gas turbines. For example, because of low fracture toughness, monolithic ceramics continue to suffer from the risk of failure due to unknown extrinsic damage events during engine service. On the other hand, ceramic matrix composites (CMC) with their ability to display much higher damage tolerance appear to be the materials of choice for current and future engine components. The objective of this paper is to briefly review the design and property status of CMC materials for implementation within the combustor and turbine sections for gas turbine engine applications. It is shown that although CMC systems have advanced significantly in thermo-structural performance within recent years, certain challenges still exist in terms of producibility, design, and affordability for commercial CMC turbine components. Nevertheless, there exist some recent successful efforts for prototype CMC components within different engine types.

  18. A Search for Hot, Diffuse Gas in Superclusters

    NASA Technical Reports Server (NTRS)

    Boughn, Stephen P.

    1998-01-01

    The HEA01 A2 full sky, 2-10 keV X-ray map was searched for diffuse emission correlated with the plane of the local supercluster of galaxies and a positive correlation was found at the 99% confidence level. The most obvious interpretation is that the local supercluster contains a substantial amount of hot (10(exp 8) OK), diffuse gas, i.e. ionized hydrogen, with a density on the order of 2 - 3 x 10(exp -6) ions per cubic centimeter. This density is about an order of magnitude larger than the average baryon density of the universe and is consistent with a supercluster collapse factor of 10. The implied total mass is of the order of 10(exp 16) times the mass of the sun and would constitute a large fraction of the baryonic matter in the local universe. This result supports current thinking that most of the ordinary matter in the universe is in the form of ionized hydrogen; however, the high temperature implied by the X-ray emission is at the top of the range predicted by most theories. The presence of a large amount of hot gas would leave its imprint on the Cosmic Microwave Background (CMB) via the Sunyaev-Zel'dovich (SZ) effect. A marginal decrement (-17 muK) was found in the COBE 4-year 53 GHz CMB map coincident with the plane of the local supercluster. Although the detection is only 1beta, the level is consistent with the SZ effect predicted from the hot gas. If these results are confirmed by future observations they will have important implications for the formation of large-scale structure in the universe. Three other projects related directly to the HEAO 1 map or the X-ray background in general benefited from this NASA grant. They are: (1) "Correlations between the Cosmic X-ray and Microwave Backgrounds: Constraints on a Cosmological Constant"; (2) "Cross-correlation of the X-ray Background with Radio Sources: Constraining the Large-Scale Structure of the X-ray Background"; and (3) "Radio and X-ray Emission Mechanisms in Advection Dominated Accretion Flow".

  19. Fluidized-Bed Reactor and Hot Gas Cleanup Facility

    SciTech Connect

    Rockey, J.M.

    1996-12-31

    As part of the Morgantown Energy Technology Center`s (METC) Advanced Gasification and Hot Gas Cleanup Facility, a 907 kg (1 ton) coal-per-day (10-inch inside diameter) jetting fluidized-bed gasifier provides realistic fuel gas for testing and developing high-temperature, high-pressure components and processes in a reducing (gasification) and oxidizing (combustion) environment. Operated mainly as a gasifier, the 0.25-m (10-inch) diameter reactor produces up to 227 kg/hr (500 lb/hr) of coal gas at 866 K (1,100{degrees}F) and 30 atmospheres (425 psig) for downstream testing. The raw coal gas is sampled for major and trace species and sent to a filter vessel capable of operating at 894 K (1,150{degrees}F) and 20 atmospheres (290 psig) of pressure. After particulate removal, the gas can be independently controlled to up to five sampling or reaction vessels including fluid-bed desulfurization, transport desulfurization, chloride, alkali, or other contaminant removal or recovery processes. The fluid-bed desulfurizer is capable of being isolated, purged, and exposed to an oxidizing environment for sorbent regeneration or other oxidation reaction. Isokinetic hazardous air pollutant (HAPS) monitoring is provided at the upstream and downstream of particulate removal. Over the post three years, 1,200 hours of operation have been completed in support of six separate Cooperative Research and Development Agreements (CRADAs). These research agreements have been in the areas of candle filters and materials testing, direct sulfur recovery from sorbent regeneration tail gases, and gasifier development.

  20. Kinetics of hot-gas desulfurization sorbents for transport reactors

    SciTech Connect

    K.C. Kwon

    2000-01-01

    Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated by many researchers to remove effectively hydrogen sulfide with various metal oxide sorbents at elevated temperatures. Various metal oxide sorbents are formulated with metal oxides such as Fe, Co, Zn, and Ti. Initial reaction kinetics of formulated sorbents with hydrogen sulfide is studied in the presence of various amounts of moisture and hydrogen at various reaction temperatures. The objectives of this research are to study initial reaction kinetics for a sorbent-hydrogen sulfide heterogeneous reaction system, to investigate effects of concentrations of hydrogen sulfide, hydrogen, and moisture on dynamic absorption of H{sub 2}S into sorbents, to understand effects of space time of reaction gas mixtures on initial reaction kinetics of the sorbent-hydrogen sulfide system, and to evaluate effects of temperature and sorbent amounts on dynamic absorption of H{sub 2}S into sorbents. Experimental data on initial reaction kinetics of hydrogen sulfide with metal oxide sorbents were obtained with a 0.83-cm{sup 3} differential reactor. The reactivity of MCRH-67 sorbent and AHI-1 was examined. These sorbents were obtained from the Research Triangle Institute (RTI). The sorbents in the form of 70 {micro}m particles are reacted with 1,000--4,000 ppm hydrogen sulfide at 450--600 C. The range of space time of reaction gas mixtures is 0.03--0.09 s. The range of reaction duration is 4--14,400 s.

  1. Hot gas stream application in micro-bonding technique

    NASA Astrophysics Data System (ADS)

    Andrijasevic, Daniela; Giouroudi, Ioanna; Smetana, Walter; Boehm, Stefan; Brenner, Werner

    2006-01-01

    This paper presents a new concept for bonding micro-parts with dimensions in the range of 50 μm to 300 μm. Two different kinds of adhesives - polyurethane adhesive foil and hot melt glue - were applied to a basic substrate by different techniques. The focused and concentrated hot gas stream softened glue which had been applied in a solid state. Micro-parts were then embossed in the softened glue, or covered and shielded by it. In this way, a rigid and compact bond was obtained after cooling. For the positioning of micro-parts (optical fibers), it has been necessary to manufacture adequate V-grooves. Finite element analyses using the ANSYS TM program package were performed in order to evaluate parameters which govern the heat transfer to the adhesive and substrate respectively. Experimental results are in good agreement with results obtained by the numerical simulations. The advantages of this new approach are small system size, low capital costs, simple usage, applicability to many material combinations, easy integration into existing production lines, etc.

  2. Scale-Up of Advanced Hot-Gas Desulfurization Sorbents

    SciTech Connect

    Jothimurugesan, K.; Gangwal, Santosh K.

    1996-10-14

    The overall objective of this project is to develop regenerable sorbents for hot gas desulfurization in IGCC systems. The specific objective of the project is to develop durable advanced sorbents that demonstrate a strong resistance to attrition and chemical deactivation, and high activity at temperatures as low as 343 C (650 F). A number of formulations will be prepared and screened in a 1/2-inch fixed bed reactor at high pressure (1 to 20 atm) and high temperatures using simulated coal-derived fuel-gases. Screening criteria will include, chemical reactivity, stability, and regenerability over the temperature range of 343 C to 650 C. After initial screening, at least 3 promising formulations will be tested for 25-30 cycles of absorption and regeneration. One of the superior formulations with the best cyclic performance will be selected for investigating scale up parameters. The scaled-up formulation will be tested for long term durability and chemical reactivity.

  3. 3-D woven ceramic composite hot gas filter development

    SciTech Connect

    Lane, Jay E.; LeCostaouec, Jean-Francois; LeCostaouec, J.F., Westinghouse

    1998-01-01

    Westinghouse, with Techniweave as a major subcontractor, is conducting a three-phase program aimed at providing advanced candle filters for a 1997 pilot-scale demonstration in one of the two hot- gas filter systems at Southern Company Service`s Wilsonville PSD Facility. The Base Program (Phases I and 11) goal is to develop and demonstrate the suitability of the Westinghouse/ Techniweave next- generation, composite, candle filter for use in Pressurized Fluidized- Bed Combustion (PFBC) and/or Integrated Gasification Combined-Cycle (IGCC) power generation systems. The Optional Task (Phase 111, Task 5) objective is to fabricate, inspect, and ship to Wilsonville 50 advanced candle filters for pilot-scale testing.

  4. Engineering a new material for hot gas cleanup

    SciTech Connect

    Wheelock, T.D.; Doraiswamy, L.K.; Constant, K.

    2000-03-01

    The engineering development of a promising sorbent for desulfurizing hot coal gas was initiated and preliminary results are presented. The sorbent is calcium-based and is designed to be regenerated and reused repeatedly. It is prepared by pelletizing powdered limestone in a rotating drum pelletizer followed by the application of a coating which becomes a strong, porous shell upon further treatment. The resulting spherical pellets combine the high reactivity of lime with the strength of an inert protective shell. Preliminary work indicates that a satisfactory shell material is comprised of a mixture of ultrafine alumina powder, somewhat coarser alumina particles, and pulverized limestone which upon heating to 1,373 K (1,100 C) becomes a coherent solid through the mechanism of particle sintering. Several batches of core-in-shell pellets were prepared and tested with encouraging results.

  5. Development of ceramic composite hot-gas filters

    SciTech Connect

    Judkins, R.R.; Stinton, D.P.; Smith, R.G.; Fischer, E.M.; Eaton, J.H.; Weaver, B.L.; Kahnke, J.L.; Pysher, D.J.

    1995-04-01

    A novel type of hot-gas filter based on a ceramic fiber-reinforced ceramic matrix was developed and extended to fullsize, 60-mm OD by 1.5-meter-long, candle filters. A commercially viable process for producing the filters was developed, and the filters are undergoing testing and demonstration throughout the world for applications in pressurized fluidized-bed combustion (PFBC) and integrated gasification combined cycle (IGCC) plants. Development activities at Oak Ridge National Laboratory (ORNL) and at the 3M Company, and testing at the Westinghouse Science and Technology Center (STC) are presented. Demonstration tests at the Tidd PFBC are underway. Issues identified during the testing and demonstration phases of the development are discussed. Resolution of the issues and the status of commercialization of the filters are described.

  6. Hot coal gas desulfurization with manganese-based sorbents

    SciTech Connect

    Hepworth, M.T.; Ben-Slimane, R.

    1995-11-01

    The primary major deposit of manganese in the US which can be readily mined by an in situ process is located in the Emily district of Minnesota. The US Bureau of Mines Research Centers at both the Twin Cities and Salt Lake City have developed a process for extracting and refining manganese in the form of a high-purity carbonate product. This product has been formulated into pellets by a multi-step process of drying, calcination, and induration to produce relatively high-strength formulations which are capable of being used for hot fuel gas desulfurization. These pellets, which have been developed at the University of Minnesota under joint sponsorship of the US Department of Energy and the US Bureau of Mines, appear superior to other, more expensive, formulations of zinc titanate and zinc ferrite which have previously been studied for multi-cycle loading (desulfurization) and regeneration (evolution of high-strength SO{sub 2} and restoration of pellet reactivity). Although these other formulations have been under development for the past twelve years, their prices still exceed $7 per pound. If manganese pellets perform as predicted in fixed bed testing, and if a significant number of utilities which burn high-sulfur coals incorporate combined-cycle gasification with hot coal gas desulfurization as a viable means of increasing conversion efficiencies, then the potential market for manganese pellets may be as high as 200,000 tons per year at a price not less than $3 per pound. This paper discusses the role of manganese pellets in the desulfurization process with respect to the integrated gasification combined-cycle (IGCC) for power generation.

  7. Sintered metal candle filter for hot gas cleaning

    SciTech Connect

    Wu Jinhu; Xu Yifeng; Cheng Hanshi; Zhang Jianmin; Ding Guishan

    1997-12-31

    A kind of sintered metal candle filter has been developed to enable the performance testing for use in hot coal gas clean-up. The intention of this paper is to provide a brief overview of development of the filter, and to provide a summary of experimental results that have been gained in testing at a pilot gasifier. Two different types of stainless steel were chosen as the material to build the filter. The operational temperature range is 460--650 C. The typical inlet dust concentration is 1.0--37.71g/Nm{sup 3}. Results show the average collection efficiency is higher than 99%, the outlet dust concentration is lower than 10mg/Nm{sup 3}, which reaches the requirement of gas turbines in IGCC. The pressure drop is about 8,300--17,400Pa, and the back blowing of the filter proves to be very good. At present only single-tube testing was conducted. The multi-tube testing facility will be established, and the authors will perform the tests under the condition of high pressure to obtain more experience for design and operation.

  8. SCALE-UP OF ADVANCED HOT-GAS DESULFURIZATION SORBENTS

    SciTech Connect

    K. JOTHIMURUGESAN; S.K. GANGWAL

    1998-03-01

    The objective of this study was to develop advanced regenerable sorbents for hot gas desulfurization in IGCC systems. The specific objective was to develop durable advanced sorbents that demonstrate a strong resistance to attrition and chemical deactivation, and high sulfidation activity at temperatures as low as 343 C (650 F). Twenty sorbents were synthesized in this work. Details of the preparation technique and the formulations are proprietary, pending a patent application, thus no details regarding the technique are divulged in this report. Sulfidations were conducted with a simulated gas containing (vol %) 10 H{sub 2}, 15 CO, 5 CO{sub 2}, 0.4-1 H{sub 2}S, 15 H{sub 2}O, and balance N{sub 2} in the temperature range of 343-538 C. Regenerations were conducted at temperatures in the range of 400-600 C with air-N{sub 2} mixtures. To prevent sulfation, catalyst additives were investigated that promote regeneration at lower temperatures. Characterization were performed for fresh, sulfided and regenerated sorbents.

  9. Development of advanced hot-gas desulfurization processes

    SciTech Connect

    Jothimurugesan, K.

    1999-04-26

    Advanced integrated gasification combined cycle (IGCC) power plants nearing completion, such as Sierra-Pacific, employ a circulating fluidized-bed (transport) reactor hot-gas desulfurization (HGD) process that uses 70-180 {micro}m average particle size (aps) zinc-based mixed-metal oxide sorbent for removing H{sub 2}S from coal gas down to less than 20 ppmv. The sorbent undergoes cycles of absorption (sulfidation) and air regeneration. The key barrier issues associated with a fluidized-bed HGD process are chemical degradation, physical attrition, high regeneration light-off (initiation) temperature, and high cost of the sorbent. Another inherent complication in all air-regeneration-based HGD processes is the disposal of the problematic dilute SO{sub 2} containing regeneration tail-gas. Direct Sulfur Recovery Process (DSRP), a leading first generation technology, efficiently reduces this SO{sub 2} to desirable elemental sulfur, but requires the use of 1-3% of the coal gas, thus resulting in an energy penalty to the plant. Advanced second-generation processes are under development that can reduce this energy penalty by modifying the sorbent so that it could be directly regenerated to elemental sulfur. The objective of this research is to support the near and long term DOE efforts to commercialize the IGCC-HGD process technology. Specifically we aim to develop: optimized low-cost sorbent materials with 70-80 {micro}m average aps meeting all Sierra specs; attrition resistant sorbents with 170 {micro}m aps that allow greater flexibility in the choice of the type of fluidized-bed reactor e.g. they allow increased throughput in a bubbling-bed reactor; and modified fluidizable sorbent materials that can be regenerated to produce elemental sulfur directly with minimal or no use of coal gas. The effort during the reporting period has been devoted to development of optimized low-cost zinc-oxide-based sorbents for Sierra-Pacific. The sorbent surface were modified to prevent

  10. X-ray properties of the starburst-driven outflow in NGC 253 .

    NASA Astrophysics Data System (ADS)

    Mitsuishi, I.; Yamasaki, N. Y.; Takei, Y.

    For a further understanding of a galactic-scale starburst-driven outflow, the X-ray properties of the hot interstellar gas in a well-studied nearby edge-on starburst galaxy, NGC 253, were investigated. Spectroscopic analysis was performed in three regions of the galaxy characterized by multiwavelength observations, i.e., the superwind region, the disk region and the halo region. The hot gas can be represented by two thin thermal plasmas (kT ˜0.2 and ˜0.6 keV) with various emission lines such as O, Ne, Mg, Si and Fe, in all three regions. Abundance patterns, i.e., O/Fe, Ne/Fe, Mg/Fe and Si/Fe, are consistent among the three regions, which suggests a common origin of the hot gas. Abundance patterns are heavily contaminated by type II supernova, which supports an indication that the hot gas in the halo region originates from the central starburst activity. Energetics can also provide the same conclusion if 0.01-50 eta 1/2 % of the total emission in the nuclear region has been transported into the halo region. The obtained polytropic equation of state of the hot gas between the density and the temperature suggests that the hot gas expands adiabatically in the disk region while it moves as free expansion in the halo region towards the outer part of the halo region as the outflow. The outflow velocity of >100 km s-1 is required and it is indicated that the hot gas can escape from the gravitational potential of NGC 253 by combining the outflow velocity and the thermal velocity.

  11. INVESTIGATION OF DUAL ACTIVE NUCLEI, OUTFLOWS, SHOCK-HEATED GAS, AND YOUNG STAR CLUSTERS IN MARKARIAN 266

    SciTech Connect

    Mazzarella, J. M.; Chan, B. H. P.; Iwasawa, K. E-mail: bchan@ipac.caltech.edu; and others

    2012-11-01

    Results of observations with the Spitzer, Hubble, GALEX, Chandra, and XMM-Newton space telescopes are presented for the luminous infrared galaxy (LIRG) merger Markarian 266. The SW (Seyfert 2) and NE (LINER) nuclei reside in galaxies with Hubble types SBb (pec) and S0/a (pec), respectively. Both companions are more luminous than L* galaxies and they are inferred to each contain a Almost-Equal-To 2.5 Multiplication-Sign 10{sup 8} M{sub Sun} black hole. Although the nuclei have an observed hard X-ray flux ratio of f{sub X} (NE)/f{sub X} (SW) = 6.4, Mrk 266 SW is likely the primary source of a bright Fe K{alpha} line detected from the system, consistent with the reflection-dominated X-ray spectrum of a heavily obscured active galactic nucleus (AGN). Optical knots embedded in an arc with aligned radio continuum radiation, combined with luminous H{sub 2} line emission, provide evidence for a radiative bow shock in an AGN-driven outflow surrounding the NE nucleus. A soft X-ray emission feature modeled as shock-heated plasma with T {approx} 10{sup 7} K is cospatial with radio continuum emission between the galaxies. Mid-infrared diagnostics provide mixed results, but overall suggest a composite system with roughly equal contributions of AGN and starburst radiation powering the bolometric luminosity. Approximately 120 star clusters have been detected, with most having estimated ages less than 50 Myr. Detection of 24 {mu}m emission aligned with soft X-rays, radio continuum, and ionized gas emission extending {approx}34'' (20 kpc) north of the galaxies is interpreted as {approx}2 Multiplication-Sign 10{sup 7} M{sub Sun} of dust entrained in an outflowing superwind. At optical wavelengths this Northern Loop region is resolved into a fragmented morphology indicative of Rayleigh-Taylor instabilities in an expanding shell of ionized gas. Mrk 266 demonstrates that the dust 'blow-out' phase can begin in a LIRG well before the galaxies fully coalesce during a subsequent

  12. Galaxy Outflows Without Supernovae

    NASA Astrophysics Data System (ADS)

    Sur, Sharanya; Scannapieco, Evan; Ostriker, Eve C.

    2016-02-01

    High surface density, rapidly star-forming galaxies are observed to have ≈50-100 km s-1 line of sight velocity dispersions, which are much higher than expected from supernova driving alone, but may arise from large-scale gravitational instabilities. Using three-dimensional simulations of local regions of the interstellar medium, we explore the impact of high velocity dispersions that arise from these disk instabilities. Parametrizing disks by their surface densities and epicyclic frequencies, we conduct a series of simulations that probe a broad range of conditions. Turbulence is driven purely horizontally and on large scales, neglecting any energy input from supernovae. We find that such motions lead to strong global outflows in the highly compact disks that were common at high redshifts, but weak or negligible mass loss in the more diffuse disks that are prevalent today. Substantial outflows are generated if the one-dimensional horizontal velocity dispersion exceeds ≈35 km s-1, as occurs in the dense disks that have star-formation rate (SFR) densities above ≈0.1 M⊙ yr-1 kpc-2. These outflows are triggered by a thermal runaway, arising from the inefficient cooling of hot material coupled with successive heating from turbulent driving. Thus, even in the absence of stellar feedback, a critical value of the SFR density for outflow generation can arise due to a turbulent heating instability. This suggests that in strongly self-gravitating disks, outflows may be enhanced by, but need not caused by, energy input from supernovae.

  13. Development of advanced hot-gas desulfurization processes

    SciTech Connect

    Jothimurugesan, K.

    2000-04-17

    Advanced integrated gasification combined cycle (IGCC) power plants nearing completion, such as Sierra-Pacific, employ a circulating fluidized-bed (transport) reactor hot-gas desulfurization (HGD) process that uses 70-180 {micro}m average particle size (aps) zinc-based mixed-metal oxide sorbent for removing H{sub 2}S from coal gas down to less than 20 ppmv. The sorbent undergoes cycles of absorption (sulfidation) and air regeneration. The key barrier issues associated with a fluidized-bed HGD process are chemical degradation, physical attrition, high regeneration light-off (initiation) temperature, and high cost of the sorbent. Another inherent complication in all air-regeneration-based HGD processes is the disposal of the problematic dilute SO{sub 2} containing regeneration tail-gas. Direct Sulfur Recovery Process (DSRP), a leading first generation technology, efficiently reduces this SO{sub 2} to desirable elemental sulfur, but requires the use of 1-3 % of the coal gas, thus resulting in an energy penalty to the plant. Advanced second-generation processes are under development that can reduce this energy penalty by modifying the sorbent so that it could be directly regenerated to elemental sulfur. The objective of this research is to support the near and long term DOE efforts to commercialize the IGCC-HGD process technology. Specifically we aim to develop: optimized low-cost sorbent materials with 70-80 {micro}m average aps meeting all Sierra specs; attrition resistant sorbents with 170 {micro}m aps that allow greater flexibility in the choice of the type of fluidized-bed reactor e.g. they allow increased throughput in a bubbling-bed reactor; and modified fluidizable sorbent materials that can be regenerated to produce elemental sulfur directly with minimal or no use of coal gas. The effort during the reporting period has been devoted to testing the FHR-32 sorbent. FHR-32 sorbent was tested for 50 cycles of sulfidation in a laboratory scale reactor.

  14. Starburst outflows from nearby galaxies

    NASA Technical Reports Server (NTRS)

    Waller, William H.

    1990-01-01

    Starburst outflows from NGC 5461, 1569 and M82 are discussed. The Sc I galaxy, M101, is reknowned for the kpc-size superassociations of star clusters and HII regions that dominate its spiral arms. NGC 5461 is one of the brightest of these superassociations, rivaling the Large Magellanic Cloud in H alpha luminosity. The NGC 5461 superassociation is dominated by a single unresolved HII region of outstanding luminosity (approx. 1000 Orion nebulae). Detailed examination of corresponding continuum images indicates that only the southern plume has any sort of stellar counterpart. The other plumes are clearly diffuse with no underlying hot stars. An image of NGC 1569 is discussed. Besides showing the peculiar arm noted by Zwicky (1971) and the filamentary extensions to the North and South (as noted by Hodge 1974), this image also reveals two arc-like features of diffuse ionized gas to the South. Both arcs are concentric with the bright center of the galaxy - where the super star clusters, A and B are located. The inner arc (Arc 1) appears to follow the same curve as the SW arm thus suggesting that the two features represent limb-brightened fragments of vast superbubble that was blown out by a central starburst sometime in the past. As the classic starburst galaxy, M82 displays all the luminous hallmarks of intense high-mass star formation and outflow activity. The diffuse H alpha and x ray emitting gas along the minor axis provides especially good evidence for a bipolar outflow of hot gas which is shock heating the swept-up interstellar medium (ISM) to temperatures of approx. 10(exp 4) K. An image shows the H alpha emission within the disk and along the minor axis. Another image shows the same field in the light of near-infrared. Both figures are based on charge coupled device images taken with the McGraw-Hill 1.3 m telescope (Waller 1989). The longer wavelength emission clearly shows a more extended morphology along the major axis. The morphological discrepancy is most

  15. ENGINEERING A NEW MATERIAL FOR HOT GAS CLEANUP

    SciTech Connect

    T.D. Wheelock; L.K. Doraiswamy; K.P. Constant

    2003-09-01

    The overall purpose of this project was to develop a superior, regenerable, calcium-based sorbent for desulfurizing hot coal gas with the sorbent being in the form of small pellets made with a layered structure such that each pellet consists of a highly reactive lime core enclosed within a porous protective shell of strong but relatively inert material. The sorbent can be very useful for hot gas cleanup in advanced power generation systems where problems have been encountered with presently available materials. An economical method of preparing the desired material was demonstrated with a laboratory-scale revolving drum pelletizer. Core-in-shell pellets were produced by first pelletizing powdered limestone or other calcium-bearing material to make the pellet cores, and then the cores were coated with a mixture of powdered alumina and limestone to make the shells. The core-in-shell pellets were subsequently calcined at 1373 K (1100 C) to sinter the shell material and convert CaCO{sub 3} to CaO. The resulting product was shown to be highly reactive and a very good sorbent for H{sub 2}S at temperatures in the range of 1113 to 1193 K (840 to 920 C) which corresponds well with the outlet temperatures of some coal gasifiers. The product was also shown to be both strong and attrition resistant, and that it can be regenerated by a cyclic oxidation and reduction process. A preliminary evaluation of the material showed that while it was capable of withstanding repeated sulfidation and regeneration, the reactivity of the sorbent tended to decline with usage due to CaO sintering. Also it was found that the compressive strength of the shell material depends on the relative proportions of alumina and limestone as well as their particle size distributions. Therefore, an extensive study of formulation and preparation conditions was conducted to improve the performance of both the core and shell materials. It was subsequently determined that MgO tends to stabilize the high

  16. Mapping Large-Scale Gaseous Outflows in Ultraluminous Infrared Galaxies with Keck II ESI Spectra: Spatial Extent of the Outflow

    NASA Astrophysics Data System (ADS)

    Martin, Crystal L.

    2006-08-01

    The kinematics of neutral gas and warm ionized gas have been mapped across ultraluminous starburst galaxies using the Na I λλ5890, 5896 absorption-line and Hα emission-line profiles, respectively, in Keck II ESI spectra. Blueshifted, interstellar absorption is found over extended regions, exceeding 15 kpc in several systems. An outflow diverging from the nuclear starburst would have to reach large heights to cover this area in projection. The scale height of the absorbing material could be lower, however, if the outflow emanates from a larger region of the galaxy. The large velocity gradient discovered across several outflows is inconsistent with a flow diverging from the nuclear starburst. Widespread star formation, triggered by the merger, probably drives these extended outflows via mechanical feedback from supernovae, although shocks generated by the galaxy-galaxy merger may also contribute to the formation of a hot wind. In a typical ULIG, the mass carried by the cool phase of the outflow is ~108 Msolar i.e., a few percent of the dynamical mass in the starburst region. Assuming the starburst activity has persisted for 10 Myr, the kinetic energy of the cool outflows is a few percent of the supernova energy. The cool wind is expected to be accelerated by momentum deposition, possibly from radiation pressure as well as the ram pressure of the hot, supernova-induced wind. The turnaround radii of the cool outflows are at least ~30-90 kpc, which presents a significant Na I absorption cross section. If most L>0.1L* galaxies pass through a luminous starburst phase, then relics of cool outflows will create a significant redshift-path density. Galaxy formation models should include this cool phase of the outflow in addition to a hot wind in feedback models. Data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National

  17. Hot coal gas desulfurization with manganese-based sorbents

    SciTech Connect

    Hepworth, M.T.; Ben-Slimane, R.

    1994-10-01

    In this paper, the physical and chemical behavior of several sorbent formulations fabricated from a manganese-containing compound, alundum (Al{sub 2}O{sub 3}), and a binder are addressed. The thermodynamic feasibility of hydrogen sulfide (H{sub 2}S)-removal from hot-simulated coal-gases using these sorbents and their subsequent regeneration with air are established. A formulation, FORM4-A, which consists of MnCO{sub 3}, alundum, and bentonite exhibits the best combination of capacity and reactivity; whereas, FORM1-A, which consists of Mn-ore, alundum, and dextrin exhibits the best combination of strength and reactivity. One important finding is that the capacity of the pellets for sulfur pickup from a H{sub 2}/H{sub 2}S mixture (at 950{degrees}C) and the kinetics of reduction, sulfidation and regeneration (at 1000{degrees}C) improve with recycling without compromising the strength. The leading formulation, FORM4-A, was subjected to 20 consecutive cycles of sulfidation and regeneration at 900{degrees}C in a 2-inch fixed bed reactor. The sulfidation gas was a simulated Tampella U-gas with an increased hydrogen sulfide content of 3% by volume to accelerate the rate of breakthrough, arbitrarily taken as 500 ppmv. Consistent with thermo-gravimetric analysis (TGA) on individual pellets, the fixed bed tests show small improvement in capacity and kinetics with the sulfur-loading capacity being about 22% by weight of the original pellet, which corresponds to approximately 90% bed utilization.

  18. Fracture behavior of advanced ceramic hot gas filters: Final report

    SciTech Connect

    Singh, J.P.; Majumdar, S.; Sutaria, M.; Bielke, W.

    1997-03-01

    This report presents the results of mechanical/microstructural evaluation, thermal shock/fatigue testing, and stress analyses of advanced hot-gas filters obtained from different manufacturers. These filters were fabricated from both monolithic ceramics and composites. The composite filters, made of both oxide and nonoxide materials, were in both as-fabricated and exposed conditions, whereas the monolithic filters were made only of nonoxide materials. Mechanical property measurement of composite filters included diametral compression testing with O-ring specimens and burst-testing of short filter segments with rubber plugs. In-situ strength of fibers in the composite filters was evaluated by microscopic technique. Thermal shock/fatigue resistance was estimated by measuring the strengths of filter specimens before and after thermal cycling from an air environment at elevated temperatures to a room temperature oil bath. Filter performance during mechanical and thermal shock/fatigue loadings was correlated with microstructural observations. Micromechanical models were developed to derive properties of composite filter constituents on the basis of measured mechanical properties of the filters. Subsequently, these properties were used to analytically predict the performance of composite filters during thermal shock loading.

  19. Hot coal gas desulfurization with manganese-based sorbents

    SciTech Connect

    Lynch, D.; Hepworth, M.T.

    1993-09-01

    The focus of work being performed on Hot Coal Gas Desulfurization is primarily in the use of zinc ferrite and zinc titanate sorbents; however, prior studies at the US Steel Fundamental Research Laboratories in Monroeville, PA, by E.T. Turkdogan indicated that an alternate sorbent, manganese dioxide-containing ore in mixture with alumina (75 wt % ore + 25 wt % Al{sub 2}/O{sub 3}) may be a viable alternative to zinc-based sorbents. Manganese, for example, has a lower vapor pressure in the elemental state than zinc hence it is not as likely to undergo depletion from the sorbent surface upon loading and regeneration cycles. Also manganese oxide is less readily reduced to the elemental state than iron hence the range of reduction potentials for oxygen is somewhat greater than for zinc ferrite. In addition, thermodynamic analysis of the manganese-oxygen-sulfur system shows it to be less amenable to sulfation than zinc ferrite. Potential also exists for utilization of manganese higher temperatures than zinc ferrite or zinc titanate. This presentation gives the thermodynamic background for consideration of manganese-based sorbents as an alternative to zinc ferrite. To date the work which has been in progress for nine months is limited at this stage to thermogravimetric testing of four formulations of manganese-alumina sorbents to determine the optimum conditions of pelletization and induration to produce reactive pellets.

  20. Hot coal gas desulfurization with manganese-based sorbents

    SciTech Connect

    Hepworth, M.T.; Ben-Slimane, R.

    1994-12-01

    The focus of work being performed on Hot Coal Gas Desulfurization at the Morgantown Energy Technology Center is primarily in the use of zinc ferrite and zinc titanate sorbents; however, prior studies indicated that an alternate sorbent, manganese dioxide-containing ore in mixture with alumina (75 wt % ore + 25 wt % Al{sub 2}O{sub 3}) may be a viable alternative to zinc-based sorbents. Manganese, for example, has a lower vapor pressure in the elemental state than zinc hence it is not as likely to undergo depletion from the sorbent surface upon loading and regeneration cycles. Also manganese oxide is less readily reduced to the elemental state than iron hence the range of reduction potentials for oxygen is somewhat greater than for zinc ferrite. In addition, thermodynamic analysis of the manganese-oxygen-sulfur system shows it to be less amenable to sulfation than zinc ferrite. Potential also exists for utilization of manganese at higher temperatures than zinc ferrite or zinc titanate. This annual topical report documents progress in pelletizing and testing via thermo-gravimetric analysis of individual pellet formulations of manganese ore/alumina combinations and also manganese carbonate/alumina with two binders, dextrin and bentonite.

  1. Scale-Up of Advanced Hot-Gas desulfurization Sorbents.

    SciTech Connect

    Jothimurugesan, K.; Gangwal, S.K.

    1997-10-02

    The overall objective of this project is to develop regenerable sorbents for hot gas desulfurization in IGCC systems. The specific objective of the project is to develop durable advanced sorbents that demonstrate a strong resistance to attrition and chemical deactivation, and high activity at temperatures as low as 343 {degrees}C (650{degrees}F). A number of formulations will be prepared and screened in a one-half inch fixed bed reactor at high pressure (1 to 20 atm) and high temperatures using simulated coal-derived fuel- gases. Screening criteria will include chemical reactivity, stability, and regenerability over the temperature range of 343{degrees}C to 650{degrees}C. After initial screening, at least 3 promising formulations will be tested for 25-30 cycles of absorption and regeneration. One of the superior formulations with the best cyclic performance will be selected for investigating scale up parameters. The scaled-up formulation will be tested for long term durability and chemical reactivity.

  2. Scale-Up of Advanced Hot-Gas Desulfurization Sorbents

    SciTech Connect

    Jothimurugesan, K.; Gangwal, S.K.

    1997-04-21

    The overall objective of this project is to develop regenerable sorbents for hot gas desulfurization in IGCC systems. The specific objective of the project is to develop durable advanced sorbents that demonstrate a strong resistance to attrition and chemical deactivation, and high activity at temperatures as low as 343{degrees}C (650{degrees}F). A number of formulations will be prepared and screened in a 1/2-inch fixed bed reactor at high pressure (1 to 20 atm) and high temperatures using simulated coal-derived fuel-gases. Screening criteria will include, chemical reactivity, stability, and regenerability over the temperature range of 343{degrees}C to 650{degrees}C. After initial screening, at least 3 promising formulations will be tested for 25-30 cycles of absorption and regeneration. One of the superior formulations with the best cyclic performance will be selected for investigating scale up parameters. The scaled-up formulation will be tested for long term durability and chemical reactivity.

  3. Outflows and Shock Chemistry

    NASA Astrophysics Data System (ADS)

    Tafalla, M.

    2016-05-01

    Bipolar outflows result from the supersonic ejection of material by a protostar, and constitute one of the most characteristic signposts of stellar birth. They also provide ideal targets to test chemical models, and can serve as templates for more complex systems of galactic and extragalactic astronomy where supersonic interactions between gas components take place.

  4. COSMIC RAYS CAN DRIVE STRONG OUTFLOWS FROM GAS-RICH HIGH-REDSHIFT DISK GALAXIES

    SciTech Connect

    Hanasz, M.; Kowalik, K.; Wóltański, D.; Lesch, H.; Naab, T.; Gawryszczak, A.

    2013-11-10

    We present simulations of the magnetized interstellar medium (ISM) in models of massive star-forming (40 M {sub ☉} yr{sup –1}) disk galaxies with high gas surface densities (Σ{sub gas} ∼ 100 M {sub ☉} pc{sup –2}) similar to observed star-forming high-redshift disks. We assume that type II supernovae deposit 10% of their energy into the ISM as cosmic rays (CRs) and neglect the additional deposition of thermal energy or momentum. With a typical Galactic diffusion coefficient for CRs (3 × 10{sup 28} cm{sup 2} s{sup –1}), we demonstrate that this process alone can trigger the local formation of a strong low-density galactic wind maintaining vertically open field lines. Driven by the additional pressure gradient of the relativistic fluid, the wind speed can exceed 10{sup 3} km s{sup –1}, much higher than the escape velocity of the galaxy. The global mass loading, i.e., the ratio of the gas mass leaving the galactic disk in a wind to the star formation rate, becomes of order unity once the system has settled into an equilibrium. We conclude that relativistic particles accelerated in supernova remnants alone provide a natural and efficient mechanism to trigger winds similar to observed mass-loaded galactic winds in high-redshift galaxies. These winds also help in explaining the low efficiencies for the conversion of gas into stars in galaxies, as well as the early enrichment of the intergalactic medium with metals. This mechanism may be at least of similar importance to the traditionally considered momentum feedback from massive stars and thermal and kinetic feedback from supernova explosions.

  5. HERSCHEL FAR-INFRARED SPECTRAL-MAPPING OF ORION BN/KL OUTFLOWS: SPATIAL DISTRIBUTION OF EXCITED CO, H{sub 2}O, OH, O, AND C{sup +} IN SHOCKED GAS

    SciTech Connect

    Goicoechea, Javier R.; Cernicharo, José; Cuadrado, Sara; Etxaluze, Mireya; Chavarría, Luis; Neufeld, David A.; Vavrek, Roland; Encrenaz, Pierre; Melnick, Gary J.; Polehampton, Edward

    2015-01-20

    We present ∼2' × 2' spectral-maps of Orion Becklin-Neugebauer/Kleinmann-Low (BN/KL) outflows taken with Herschel at ∼12'' resolution. For the first time in the far-IR domain, we spatially resolve the emission associated with the bright H{sub 2} shocked regions ''Peak 1'' and ''Peak 2'' from that of the hot core and ambient cloud. We analyze the ∼54-310 μm spectra taken with the PACS and SPIRE spectrometers. More than 100 lines are detected, most of them rotationally excited lines of {sup 12}CO (up to J = 48-47), H{sub 2}O, OH, {sup 13}CO, and HCN. Peaks 1/2 are characterized by a very high L(CO)/L {sub FIR} ≈ 5 × 10{sup –3} ratio and a plethora of far-IR H{sub 2}O emission lines. The high-J CO and OH lines are a factor of ≈2 brighter toward Peak 1 whereas several excited H{sub 2}O lines are ≲50% brighter toward Peak 2. Most of the CO column density arises from T {sub k} ∼ 200-500 K gas that we associate with low-velocity shocks that fail to sputter grain ice mantles and show a maximum gas-phase H{sub 2}O/CO ≲ 10{sup –2} abundance ratio. In addition, the very excited CO (J > 35) and H{sub 2}O lines reveal a hotter gas component (T {sub k} ∼ 2500 K) from faster (v {sub S} > 25 km s{sup –1}) shocks that are able to sputter the frozen-out H{sub 2}O and lead to high H{sub 2}O/CO ≳ 1 abundance ratios. The H{sub 2}O and OH luminosities cannot be reproduced by shock models that assume high (undepleted) abundances of atomic oxygen in the preshock gas and/or neglect the presence of UV radiation in the postshock gas. Although massive outflows are a common feature in other massive star-forming cores, Orion BN/KL seems more peculiar because of its higher molecular luminosities and strong outflows caused by a recent explosive event.

  6. Variation in the Deep Gas Composition in Hot Spots on Jupiter

    NASA Astrophysics Data System (ADS)

    Bjoraker, Gordon; de Pater, Imke; Wong, Michael H.; Adamkovics, Mate; Hewagama, Tilak; Hesman, Brigette

    2015-11-01

    We used CSHELL on NASA’s Infrared Telescope Facility and NIRSPEC on the Keck telescope in the last two years to spectrally resolve line profiles of CH3D, NH3, PH3, and H2O in 5-micron Hot Spots on Jupiter. The profile of the CH3D lines at 4.66 microns is very broad in both NEB and SEB Hot Spots due to collisions with up to 8 bars of H2, where unit optical depth occurs due to collision-induced H2 opacity. The extreme width of these CH3D features implies that the Hot Spots that we observed do not have significant cloud opacity for P > 2 bars. We retrieved NH3, PH3, and gaseous H2O within Hot Spots in both the NEB and SEB. We had dry nights on Mauna Kea and a sufficient Doppler shift to detect H2O. We will compare line wings to derive H2O profiles in the 2 to 6-bar region. NEB Hot Spots are depleted in NH3 with respect to adjacent regions. Interestingly, SEB Hot Spots exhibit stronger NH3 absorption than NEB Hot Spots. In addition, SEB Hot Spots have very similar 5-micron spectra as neighboring longitudes in the SEB, implying similar deep gas composition. The dynamical origin of SEB Hot Spots is much less studied than that of NEB Hot Spots, so our observations of gas composition in both regions may constrain mechanisms for forming Hot Spots.

  7. Performance of PRD-66 hot gas candle filters in the AEP/TIDD PFBC facility

    SciTech Connect

    Chambers, J.A.

    1996-12-31

    The performance of PRD-66 hot gas filters in American Electric Power`s TIDD PFBC facility is described. PRD-66 hot gas filters are made of an all-oxide composition with a unique layered microstructure which lends corrosion resistance, high temperature stability and excellent resistance to thermal shock damage. The development of the PRD-66 material into a hot gas candle filter is recounted. Testing which guided filter development prior to exposure in the AEP/TIDD PFBC system is discussed. Future plans for testing in coal combustion and other industrial applications are described.

  8. Studies of the Hot Gas in the Galactic halo and Local Bubble

    NASA Technical Reports Server (NTRS)

    Shelton, Robin L.

    2003-01-01

    This paper presents a report on the progress made on Studies of the Hot Gas in the Galactic halo and Local Bubble at Johns Hopkins University. The broad goals of this project are to determine the physical conditions and history of the hot phase of the Galaxy's interstellar medium. Such gas resides in the Galactic halo, the Local Bubble surrounding the solar neighborhood, other bubbles, and supernova remnants. A better understanding of the hot gas and the processes occurring within it requires several types of work, including ultraviolet and X-ray data analyses and computer modeling.

  9. IONIZATION-DRIVEN FRAGMENTATION OF GAS OUTFLOWS RESPONSIBLE FOR FeLoBALs IN QUASARS

    SciTech Connect

    Bautista, Manuel A.; Dunn, Jay P.

    2010-07-10

    We show that time variations in the UV ionizing continuum of quasars, on scales of {approx}1 yr, affect the dynamic structure of the plasmas responsible for low-ionization broad absorption lines. Variations of the ionizing continuum produce non-equilibrium photoionization conditions over a significant fraction of the absorbing clouds and supersonically moving ionization fronts. When the flux drops, the contraction of the ionized region drives a supersonic cooling front toward the radiation source and a rarefaction wave in the opposite direction. The pressure imbalance is compensated by an increased speed of the cool gas relative to the front. When the flux recovers, the cool gas is re-ionized and re-heated by a supersonic ionization front traveling away from the radiation source and a forward shock is created. The re-heated clouds equilibrate to a temperature of {approx}10{sup 4} K and are observed to have different radial velocities than the main cloud. Such fragmentation seems consistent with the multicomponent structure of troughs seen in some objects. The velocity differences measured among various components in the quasars QSO 2359-1241 and SDSS J0318-0600 can be reproduced by our model if strong magnetic fields ({approx}10 mG) are present within the clouds.

  10. Ionization-driven Fragmentation of Gas Outflows Responsible for FeLoBALs in Quasars

    NASA Astrophysics Data System (ADS)

    Bautista, Manuel A.; Dunn, Jay P.

    2010-07-01

    We show that time variations in the UV ionizing continuum of quasars, on scales of ~1 yr, affect the dynamic structure of the plasmas responsible for low-ionization broad absorption lines. Variations of the ionizing continuum produce non-equilibrium photoionization conditions over a significant fraction of the absorbing clouds and supersonically moving ionization fronts. When the flux drops, the contraction of the ionized region drives a supersonic cooling front toward the radiation source and a rarefaction wave in the opposite direction. The pressure imbalance is compensated by an increased speed of the cool gas relative to the front. When the flux recovers, the cool gas is re-ionized and re-heated by a supersonic ionization front traveling away from the radiation source and a forward shock is created. The re-heated clouds equilibrate to a temperature of ~104 K and are observed to have different radial velocities than the main cloud. Such fragmentation seems consistent with the multicomponent structure of troughs seen in some objects. The velocity differences measured among various components in the quasars QSO 2359-1241 and SDSS J0318-0600 can be reproduced by our model if strong magnetic fields (~10 mG) are present within the clouds.

  11. The molecular hydrogen emission around L1551 IRS 5 - Shock-heated molecular gas at the base of the molecular outflow

    NASA Technical Reports Server (NTRS)

    Yamashita, Takuya; Tamura, Motohide

    1992-01-01

    Spatially resolved observations of the v = 1-0 S(1) molecular hydrogen emission toward L1551 IRS 5 using the grating spectrometer at KPNO are presented. The S(1) emission consists of a ridge component extending toward west along the optical jet from its peak on IRS 5 and a diffuse component which traces the innermost region of the cavity enclosed by the molecular outflow. The ridge component represents shock-heated molecular gas at the root of the optical jet. The diffuse component is too bright to be of scattered origin; it most likely arises from shock-heated gas within the cavity and could represent an acceleration process of the molecular outflow.

  12. INVESTIGATING THE POTENTIAL DILUTION OF THE METAL CONTENT OF HOT GAS IN EARLY-TYPE GALAXIES BY ACCRETED COLD GAS

    SciTech Connect

    Su, Yuanyuan; Irwin, Jimmy A.

    2013-03-20

    The measured emission-weighted metal abundance of the hot gas in early-type galaxies has been known to be lower than theoretical expectations for 20 years. In addition, both X-ray luminosity and metal abundance vary significantly among galaxies of similar optical luminosities. This suggests some missing factors in the galaxy evolution process, especially the metal enrichment process. With Chandra and XMM-Newton, we studied 32 early-type galaxies (kT {approx}< 1 keV) covering a span of two orders of L{sub X,gas}/L{sub K} to investigate these missing factors. Contrary to previous studies that X-ray faint galaxies show extremely low Fe abundance ({approx}0.1 Z{sub Sun }), nearly all galaxies in our sample show an Fe abundance at least 0.3 Z{sub Sun }, although the measured Fe abundance difference between X-ray faint and X-ray bright galaxies remains remarkable. We investigated whether this dichotomy of hot gas Fe abundances can be related to the dilution of hot gas by mixing with cold gas. With a subset of 24 galaxies in this sample, we find that there is virtually no correlation between hot gas Fe abundances and their atomic gas content, which disproves the scenario that the low metal abundance of X-ray faint galaxies might be a result of the dilution of the remaining hot gas by pristine atomic gas. In contrast, we demonstrate a negative correlation between the measured hot gas Fe abundance and the ratio of molecular gas mass to hot gas mass, although it is unclear what is responsible for this apparent anti-correlation. We discuss several possibilities including that externally originated molecular gas might be able to dilute the hot gas metal content. Alternatively, the measured hot gas Fe abundance may be underestimated due to more complex temperature and abundance structures and even a two-temperature model might be insufficient to reflect the true value of the emission weighted mean Fe abundance.

  13. Brush Seal Would Impede Flow Of Hot Gas

    NASA Technical Reports Server (NTRS)

    Carroll, Paul F.; Easter, Barry P.

    1993-01-01

    Proposed brush seal helps prevent recirculating flow of hot combustion gases from reaching bellows seal located deep in gap in wall of combustion chamber. More durable, more tolerant of irregularities, and easier to install. Seals also helpful in impeding deleterious flows of hot gases in other combustion chambers such as those of furnaces and turbomachines.

  14. ENGINEERING A NEW MATERIAL FOR HOT GAS CLEANUP

    SciTech Connect

    T.D. Wheelock; L.K. Doraiswamy; K. Constant

    2001-06-30

    The overall objective of this project is the engineering development of a reusable calcium-based sorbent for desulfurizing hot coal gas. A two-step pelletization method has been employed to produce relatively strong, ''core-in-shell,'' spherical pellets. Each pellet consists of a highly reactive core surrounded by a strong, inert, porous shell. A suitable core is composed largely of CaO which reacts with H{sub 2}S to form CaS. Pellet cores have been prepared by pelletizing either pulverized limestone or plaster of Paris, and shells have been made of various materials. The most suitable shell material has been formed from a mixture of alumina and limestone particles. The core-in-shell pellets require treatment at high temperature to convert the core material to CaO and to partially sinter the shell material. Pellet cores derived from plaster of Paris have proved superior to those derived from limestone because they react more rapidly with H{sub 2}S and their reactivity does not seem to decline with repeated loading and regeneration. The rate of reaction of H{sub 2}S with CaO derived from either material is directly proportional to H{sub 2}S concentration. The rate of reaction does not appear to be affected significantly by temperature in the range of 1113 K (840 C) to 1193 K (920 C) but decreases markedly at 1233 K (960 C). The rate is not affected by shell thickness within the range tested, which also provides adequate compressive strength.

  15. Fracture behavior of advanced ceramic hot-gas filters

    SciTech Connect

    Singh, J.P.; Majumdar, S.; Sutaria, M.; Bielke, W.

    1996-05-01

    We have evaluated the microstructural/mechanical, and thermal shock/fatigue behavior and have conducted stress analyses of hot-gas candle filters made by various manufacturers. These filters include both monolithic and composite ceramics. Mechanical-property measurement of the composite filters included diametral compression testing with O-ring specimens and burst testing of short filter segments using rubber plug. In general, strength values obtained by burst testing were lower than those obtained by O-ring compression testing. During single-cycle thermal-shock tests, the composite filters showed little or no strength degradation when quenched from temperatures between 900 and 1000{degrees}C. At higher quenching temperatures, slow strength degradation was observed. The monolithic SiC filters showed no strength degradation when quenched from temperatures of up to {approx}700-900{degrees}C, but displayed decreased strength at a relatively sharp rate when quenched from higher temperatures. On the other hand, a recrystallized monolithic SiC filter showed higher initial strength and retained this strength to higher quenching temperatures than did regular SiC filters. This may be related to the difference in strength of grain boundary phases in the two cases. In thermal cycles between room temperature and 800- 1000{degrees}C, both monolithic and composite filters show a small strength degradation up to three cycles, beyond which the strength remained unchanged. Results of rubber-plug burst testing on composite filters were analyzed to determine the anisotropic elastic constants of the composite in the hoop direction. When these results are combined with axial elastic constants determined from axial tensile tests, the composite can be analyzed for stress due to mechanical (e. g., internal pressure) or thermal loading (thermal shock during pulse cleaning). The stresses can be compared with the strength of the composite to predict filter performance.

  16. Modeling of the Dust and Gas Outflows from OH 26.5+0.6: The Superwind

    NASA Technical Reports Server (NTRS)

    Justtanont, K.; Skinner, C. J.; Tielens, A. G. G. M.; Meixner, M.; Baas, F.

    1996-01-01

    We have observed the extreme OH/IR star, OH 26.5+0.6, in the infrared dust continuum and in the sub- millimeter rotational lines of CO. Mid-infrared images reveal the compact nature of the circumstellar shell (less than 0.5 sec). A deep 9.7 microns absorption feature and an absorption at 18 microns show that the dust mass-loss rate is very high. However, the low antenna temperatures of CO J = 1-0 and 2-1 lines suggest that the outer part of the circumstellar shell is much more tenuous. In order to resolve this discrepancy, we have observed the J = 3-2 and 4-3 CO rotational transitions. We have developed a model for the circumstellar shell for OH 26.5 + 0.6 which is consistent with the infrared and submillimeter observations. The dust and gas data are well fitted by a two-shell model, consisting of a dense shell surrounded by a more tenuous shell. The former we identify with the superwind (M = 5.5 x 10(exp -4) solar mass/ yr), and the latter we identify with mass loss on the asymptotic giant branch (AGB) (M = 10(exp -6) solar mass/ yr). The transition between the two mass-loss phases is shown to be rather abrupt ((Delta)t less than 150 yr). Depending on the mass of the progenitor, this superwind phase may be the last thermal pulse (for M(sub *) less than 1.5 solar mass), or the first of a series of the superwind phases (for up to 8 solar mass), punctuated by a period of low mass-loss rates, before the star evolves off the AGB.

  17. The Scatter in the Hot Gas Content of Early-type Galaxies

    NASA Astrophysics Data System (ADS)

    Su, Yuanyuan; Irwin, Jimmy A.; White, Raymond E., III; Cooper, Michael C.

    2015-06-01

    Optically similar early-type galaxies are observed to have a large and poorly understood range in the amount of hot, X-ray-emitting gas they contain. To investigate the origin of this diversity, we studied the hot gas properties of all 42 early-type galaxies in the multiwavelength ATLAS3D survey that have sufficiently deep Chandra X-ray observations. We related their hot gas properties to a number of internal and external physical quantities. To characterize the amount of hot gas relative to the stellar light, we use the ratio of the gaseous X-ray luminosity to the stellar K-band luminosity, {L}{{X}{gas}}/{L}K; we also use the deviations of {L}{{X}{gas}} from the best-fit {L}{{X}{gas}}–L K relation (denoted {Δ }{L}{{X}{gas}}). We quantitatively confirm previous suggestions that various effects conspire to produce the large scatter in the observed {L}{X}/{L}K relation. In particular, we find that the deviations {Δ }{L}{{X}{gas}} are most strongly positively correlated with the (low rates of) star formation and the hot gas temperatures in the sample galaxies. This suggests that mild stellar feedback may energize the gas without pushing it out of the host galaxies. We also find that galaxies in high galaxy density environments tend to be massive slow rotators, while galaxies in low galaxy density environments tend to be low mass, fast rotators. Moreover, cold gas in clusters and fields may have different origins. The star formation rate increases with cold gas mass for field galaxies but it appears to be uncorrelated with cold gas for cluster galaxies.

  18. Metallicity and Quasar Outflows

    NASA Astrophysics Data System (ADS)

    Wang, Huiyuan; Zhou, Hongyan; Yuan, Weimin; Wang, Tinggui

    2012-06-01

    Correlations of the outflow strength of quasars, as measured by the blueshift and asymmetry index (BAI) of the C IV line, with intensities and ratios of broad emission lines, based on composite quasar spectra built from the Sloan Digital Sky Survey, are investigated. We find that most of the line ratios of other ions to C IV increase prominently with BAI. These behaviors can be well understood in the context of increasing metallicity with BAI. The strength of the dominant coolant, C IV line, decreases, and weak collisionally excited lines increase with gas metallicity as a result of the competition between different line coolants. Using Si IV+O IV]/C IV as an indicator of gas metallicity, we present, for the first time, a strong correlation between the metallicity and the outflow strength of quasars over a wide range of 1.7-6.9 times solar abundance. Our result implies that metallicity plays an important role in the formation of quasar outflows, likely by affecting outflow acceleration. This effect may have a profound impact on galaxy evolution via momentum feedback and chemical enrichment.

  19. METALLICITY AND QUASAR OUTFLOWS

    SciTech Connect

    Wang, Huiyuan; Zhou, Hongyan; Wang, Tinggui; Yuan, Weimin

    2012-06-01

    Correlations of the outflow strength of quasars, as measured by the blueshift and asymmetry index (BAI) of the C IV line, with intensities and ratios of broad emission lines, based on composite quasar spectra built from the Sloan Digital Sky Survey, are investigated. We find that most of the line ratios of other ions to C IV increase prominently with BAI. These behaviors can be well understood in the context of increasing metallicity with BAI. The strength of the dominant coolant, C IV line, decreases, and weak collisionally excited lines increase with gas metallicity as a result of the competition between different line coolants. Using Si IV+O IV]/C IV as an indicator of gas metallicity, we present, for the first time, a strong correlation between the metallicity and the outflow strength of quasars over a wide range of 1.7-6.9 times solar abundance. Our result implies that metallicity plays an important role in the formation of quasar outflows, likely by affecting outflow acceleration. This effect may have a profound impact on galaxy evolution via momentum feedback and chemical enrichment.

  20. PROTOSTELLAR OUTFLOW HEATING IN A GROWING MASSIVE PROTOCLUSTER

    SciTech Connect

    Wang Ke; Wu Yuefang; Zhang Huawei; Zhang Qizhou; Li Huabai

    2012-02-15

    The dense molecular clump P1 in the infrared dark cloud complex G28.34+0.06 harbors a massive protostellar cluster at its extreme youth. Our previous Submillimeter Array observations revealed several jet-like CO outflows emanating from the protostars, indicative of intense accretion and potential interaction with ambient natal materials. Here, we present the Expanded Very Large Array spectral line observations toward P1 in the NH{sub 3} (J,K) = (1,1), (2,2), (3,3) lines, as well as H{sub 2}O and class I CH{sub 3}OH masers. Multiple NH{sub 3} transitions reveal the heated gas widely spread in the 1 pc clump. The temperature distribution is highly structured; the heated gas is offset from the protostars, and morphologically matches the outflows very well. Hot spots of spatially compact, spectrally broad NH{sub 3} (3,3) emission features are also found coincident with the outflows. A weak NH{sub 3} (3,3) maser is discovered at the interface between an outflow jet and the ambient gas. These findings suggest that protostellar heating may not be effective in suppressing fragmentation during the formation of massive cores.

  1. Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems

    SciTech Connect

    Nick Soelberg; Joe Enneking

    2011-05-01

    Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (radioactive and hazardous) wastes. Test programs performed in recent years have shown that mercury in off-gas streams from processes that treat radioactive wastes can be controlled using fixed beds of activated sulfur-impregnated carbon, to levels low enough to comply with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. Carbon bed hot spots or fires have occurred several times during these tests, and also during a remediation of tanks that contained mixed waste. Hot spots occur when localized areas in a carbon bed become heated to temperatures where oxidation occurs. This heating typically occurs due to heat of absoption of gas species onto the carbon, but it can also be caused through external means such as external heaters used to heat the carbon bed vessel. Hot spots, if not promptly mitigated, can grow into bed fires. Carbon bed hot spots and fires must be avoided in processes that treat radioactive and mixed waste. Hot spots are detected by (a) monitoring in-bed and bed outlet gas temperatures, and (b) more important, monitoring of bed outlet gas CO concentrations. Hot spots are mitigated by (a) designing for appropriate in-bed gas velocity, for avoiding gas flow maldistribution, and for sufficient but not excessive bed depth, (b) appropriate monitoring and control of gas and bed temperatures and compositions, and (c) prompt implementation of corrective actions if bed hot spots are detected. Corrective actions must be implemented quickly if bed hot spots are detected, using a graded approach and sequence starting with corrective actions that are simple, quick, cause the least impact to the process, and are easiest to recover from.

  2. Bench-scale demonstration of hot-gas desulfurization technology. First quarterly report, 1997

    SciTech Connect

    1997-07-01

    The U.S. Department of Energy (DOE), Federal Energy Technology Center (FETC), is sponsoring research in advanced methods for controlling contaminants in hot coal gasifier gas (coal-derived fuel-gas) streams of integrated gasification combined-cycle (IGCC) power systems. The hot gas cleanup work seeks to eliminate the need for expensive heat recovery equipment, reduce efficiency losses due to quenching, and minimize wastewater treatment costs. Hot-gas desulfurization research has focused on regenerable mixed-metal oxide sorbents that can reduce the sulfur in coal-derived fuel-gas to less than 20 ppmv and can be regenerated in a cyclic manner with air for multicycle operation. Zinc titanate (Zn{sub 2}TiO{sub 4} or ZnTiO{sub 3}), formed by a solid-state rea of zinc oxide (ZnO) and titanium dioxide (TiO{sub 2}), is currently one of the leading sorbents.

  3. Task 6.5 - Gas Separation and Hot-Gas Cleanup

    SciTech Connect

    Swanson, Michael L.; Ness Jr., Robert O.; Hurley, John P.; McCollor, Donald P.

    1997-06-01

    Catalytic gasification of coal to produce H{sub 2}- and CH{sub 4}-rich gases for consumption in molten carbonate fuel cells is currently under development; however, to optimize the fuel cell performance and extend its operating life, it is desired to separate as much of the inerts (i.e., CO{sub 2} and N{sub 2}) and impurities (i.e., H{sub 2}S and NH{sub 3}) as possible from the fuel gas before they enter the fuel cell. In addition, the economics of the integrated gasification combined cycle (IGCC) can be improved by separating as much of the hydrogen as possible from the fuel, since hydrogen is a high-value product. One process currently under development by the Energy & Environmental Research Center (EERC) for accomplishing this gas separation and hot-gas cleanup involves gas separation membranes. These membranes are operated at temperatures as high as 800 C and pressures up to 300 psig. Some of these membranes can have very small pores (30-50 {angstrom}), which inefficiently separate the undesired gases by operating in the Knudsen diffusion region of mass transport. Other membranes with smaller pore sizes (<5 {angstrom}) operate in the molecular sieving region of mass transport phenomena, Dissolution of atomic hydrogen into thin metallic membranes made of platinum and palladium alloys is also being developed. Technological and economic issues that must be resolved before gas separation membranes are commercially viable include improved gas separation efficiency, membrane optimization, sealing of membranes in pressure vessels, high burst strength of the ceramic material, pore thermal stability, and material chemical stability. Hydrogen separation is dependent on the temperature, pressure, pressure ratio across the membrane, and ratio of permeate flow to total flow. For gas separation under Knudsen diffusion, increasing feed pressure and pressure ratio across the membrane should increase gas permeability; decreasing the temperature and the permeate-to-total flow

  4. The Interaction of Hot and Cold Gas in the Disk and Halo of Galaxies

    NASA Technical Reports Server (NTRS)

    Slavin, Jonathan; Salamon, Michael (Technical Monitor)

    2004-01-01

    Most of the thermal energy in the Galaxy and perhaps most of the baryons in the Universe are found in hot (log T approximately 5.5 - 7) gas. Hot gas is detected in the local interstellar medium, in supernova remnants (SNR), the Galactic halo, galaxy clusters and the intergalactic medium (IGM). In our own Galaxy, hot gas exists in large superbubbles up to several hundred pc in diameter that locally dominate the interstellar medium (ISM) and determine its thermal and dynamic evolution. While X-ray observations using ROSAT, Chandra and XMM have allowed us to make dramatic progress in mapping out the morphology of the hot gas and in understanding some of its spectral characteristics, there remain fundamental questions that are unanswered. Chief among these questions is the way that hot gas interacts with cooler phase gas and the effects these interactions have on hot gas energetics. The theoretical investigations we proposed in this grant aim to explore these interactions and to develop observational diagnostics that will allow us to gain much improved information on the evolution of hot gas in the disk and halo of galaxies. The first of the series of investigations that we proposed was a thorough exploration of turbulent mixing layers and cloud evaporation. We proposed to employ a multi-dimensional hydrodynamical code that includes non-equilibrium ionization (NEI), radiative cooling and thermal conduction. These models are to be applied to high velocity clouds in our galactic halo that are seen to have O VI by FUSE (Sembach et ai. 2000) and other clouds for which sufficient constraining observations exist.

  5. High Velocity Outflows in Quasars

    NASA Astrophysics Data System (ADS)

    Hamann, Fred; Rodriguez Hidalgo, Paola; Nestor, Daniel

    2006-02-01

    High velocity (HV) outflows are important components of SMBH growth and evolution. The ability of SMBHs to accrete matter and light up as AGN probably requires that outflows are present to carry away angular momentum. Outflows during the luminous AGN phase might also play a critical role in ``unveiling" young dust-enshrouded AGN and in ``polluting" the intergalactic medium with metals at high redshifts. Nonetheless, AGN outflows remain poorly understood. We have begun a program to study a nearly unexplored realm of AGN outflow parameter space: HV winds with v> 10,000 km/s up to v~ 0.2c but small velocity dispersions (narrow absorption lines), such that v/(Delta) v ≫ 1. These extreme outflows have been detected so far in just a few quasars, but they might be ubiquitous if, as expected, the flows subtend a small solid angle as seen from the central engine. Narrow-line HV flows merit specific attention because they pose unique challenges for theoretical models of the wind acceleration, mass loss rates, launch radii, etc. They might also comprise a significant fraction of absorbers previously attributed to unrelated (interveinng) gas or galaxies. We have compiled a list of bright quasars with candidate HV outflow lines (CIV 1550 A) in existing SDSS spectra. We now propose to observe ~50 of these candidates with the 2.1m GoldCam to i) identify/confirm some of the true outflow systems (based on line variability), ii) place a firm lower limit on the fraction of quasars with narrow-line HV outflows, iii) compile a short list of confirmed HV outflow sources for future study, and iv) use the combined SDSS and GoldCam data to measure or constrain basic outflow properties, such as the kinematics, locations, and physical conditions.

  6. Hot gas cleanup for molten carbonate fuel cells. A zinc oxide reactor model, Final report

    SciTech Connect

    Steinfeld, G.

    1980-09-16

    Utilization of coal gasifiers to power MCFC requires a cleanup system to remove sulfur and particulates. Of the two near term options available for desulfurization of gasifier effluent, namely low temperature cleanup utilizing absorber/stripper technology, and hot gas cleanup utilizing metal oxides, there is a clear advantage to using hot gas cleanup. Since the MCFC will operate at 1200/sup 0/F, and the gasifier effluent could be between 1200 to 1900/sup 0/F, a hot gas cleanup system will require little or no change in process gas temperature, thereby contributing to a high overall system efficiency. A hot gas cleanup system will consist of FeO for bulk H/sub 2/S removal and ZnO for reduction of H/sub 2/S to sub ppM levels. Hot gas cleanup systems at present are not available commercially, and therefore it is the objective of this project to model the components of the system in order to help bring this technology closer to commercialization, by providing simulated operating characteristics to aid in system design, and system simulations of gasifier/MCFC systems. The modeling of the ZnO reactor is presented.

  7. Task 3.10 - Gas Separation and Hot-Gas Cleanup: Topical report, August 1995

    SciTech Connect

    Swanson, M.L.

    1997-12-31

    Catalytic gasification of coal to produce H{sub 2}-, CO-, and CH{sub 4}-rich mixtures of gases for consumption in molten carbonate fuel cells is currently under development; however, to optimize the fuel cell performance and extend its operating life, it is desired to separate as much of the inert components (i.e., CO{sub 2} and N{sub 2}) and impurities (i e., H{sub 2}S and NH{sub 3}) as possible from the fuel gas before it enters the fuel cell. In addition, the economics of the integrated gasification combined cycle (IGCC) can be improved by separating as much of the hydrogen as possible from the fuel, since hydrogen is a high-value product. Researchers at the Energy {ampersand} Environmental Research Center (EERC) and Bend Research, Inc., investigated pressure-driven membranes as a method for accomplishing this gas separation and hot- gas cleanup. These membranes are operated at temperatures as high as 800{degrees}C and at pressures up to 300 psig. They have very small pore sizes that separate the undesirable gases by operating in the Knudsen diffusion region of mass transport (30-50 A) or in the molecular sieving region of mass transport phenomena (less than 5A). In addition, H{sub 2} separation through a palladium metal membrane proceeds via a solution- diffusion mechanism for atomic hydrogen. This allows the membranes to exhibit extremely high selectivity for hydrogen separation.

  8. Separation Characteristics of Heavy Metal Compounds by Hot Gas Cleaning System

    SciTech Connect

    Sakano, T.; Kanaoka, C.; Furuuchi, M.; Yang, K-S.; Hata, M.

    2002-09-20

    The purpose of this research is the basic study for the development of separation technology of heavy metal compounds from hot flue gas. While the hot flue gas containing heavy metals from a melting furnace of industrial waste passes through the high temperature dust collector which can be varied the operating temperature. The heavy metals can be separated due to different boiling point of each heavy metal. On the basis of this concept, the concentration of heavy metals in the flue gas were sampled and measured at inlet, outlet of the ceramic filter housing in the actual industrial waste processing system. Speciation of heavy metals in collected ashes was clarified by separating heavy metals according to compounds using their elution characteristics. Moreover, equilibrium analysis was performed to determine the effect of temperature, flue gases conditions on heavy metals speciation, and it was compared with experimental data. From these results, we discussed about separation performance of heavy metal compounds by hot gas cleaning.

  9. Experimental and Numerical Investigations on Flue Gas Purification during Hot Gas Filtration

    SciTech Connect

    Thulfaut, C.; Renz, U.

    2002-09-19

    The aim of the actual investigations is to integrate the catalytic reduction of carbon monoxide and particularly nitric oxides into the hot gas filtration process with ceramic filter elements of fluidized bed combustors which mainly represent an important N2O-source. According to Klein (Klein 1994) worldwide approx. 260 coal-fired power plants with fluidized bed combustors in the power range > 50 MWel existed in 1994, to which approx. 1% of the global coal dissipation corresponds. These emitted dinitrogen oxide with 70 kt/a, however, 20% of the entire N2O amounts from stationary firing plants. After Kleins calculations an increase of coal-fired fluidized bed combustors only by 10% triples the N2O emission.

  10. Partial oxidation process for producing a stream of hot purified gas

    DOEpatents

    Leininger, Thomas F.; Robin, Allen M.; Wolfenbarger, James K.; Suggitt, Robert M.

    1995-01-01

    A partial oxidation process for the production of a stream of hot clean gas substantially free from particulate matter, ammonia, alkali metal compounds, halides and sulfur-containing gas for use as synthesis gas, reducing gas, or fuel gas. A hydrocarbonaceous fuel comprising a solid carbonaceous fuel with or without liquid hydrocarbonaceous fuel or gaseous hydrocarbon fuel, wherein said hydrocarbonaceous fuel contains halides, alkali metal compounds, sulfur, nitrogen and inorganic ash containing components, is reacted in a gasifier by partial oxidation to produce a hot raw gas stream comprising H.sub.2, CO, CO.sub.2, H.sub.2 O, CH.sub.4, NH.sub.3, HCl, HF, H.sub.2 S, COS, N.sub.2, Ar, particulate matter, vapor phase alkali metal compounds, and molten slag. The hot raw gas stream from the gasifier is split into two streams which are separately deslagged, cleaned and recombined. Ammonia in the gas mixture is catalytically disproportionated into N.sub.2 and H.sub.2. The ammonia-free gas stream is then cooled and halides in the gas stream are reacted with a supplementary alkali metal compound to remove HCl and HF. Alkali metal halides, vaporized alkali metal compounds and residual fine particulate matter are removed from the gas stream by further cooling and filtering. The sulfur-containing gases in the process gas stream are then reacted at high temperature with a regenerable sulfur-reactive mixed metal oxide sulfur sorbent material to produce a sulfided sorbent material which is then separated from the hot clean purified gas stream having a temperature of at least 1000.degree. F.