06405 Species measurements in a hypersonic hydrogen-air, combustion wake

06405 Species measurements in a hypersonic hydrogen-air, combustion wake

09 Combustion (burners, combustion systems) 96lO6393 P rolysir of rim lo coal model corn unds contalnlng aromat7c carboxyllc acPds: Does decarboxy p...

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09

Combustion (burners, combustion systems)

96lO6393 P rolysir of rim lo coal model corn unds contalnlng aromat7c carboxyllc acPds: Does decarboxy p” atlon lead to croulinklng? Eskay, T. B. et al., Prepr. Pap.-Am. Chem. Sot., Div. Fuel Chem., 1996, 41, (2). 739-743. T$ ~1” r inye.$igates the thermolysis of 1,2-$3,3’-dicarboxyphenyl thaye :g\ 4,4 -dlcarbox9 phenyl)ethane at 400 C as models of car t xyhc acids m ow rank co s. The major decomposition pathway observed is decarboxylation, which mainly occurs by an ionic pathway.

96/06401 Slmultanrour drylng and pyrolyols of solld fuel particles Saastamoinen, J. and Richard, J. R. Combustion & Flame, Aug. 1996, 106, (3), 288-300. In this paper a novel and efficient numerical method is presented for the calculation of coupled drying and devolatilization rates. These processes are coupled, when the size of a particle is large. In addition, a novel heattransfer limited model for devolatilization of large particles is presented.

Pyrolysb of rllghtly coking coal under the load of 96106394 mechanlcal pressure for enhancing caking properties Miura, K. et aL, Coal Sci. Techno/., 1995, 24, 1025-1028. It was found that the formations of H, CO and H,O in coal cokin were significantly suppressed, whereas the formations of CO, and light g ydrocarbon gases were enhanced with an increase in loading pressure. Both the solid yield and the amount of THF soluble matter increased with increasing pressure.

Size dlstrlbutlon of micropores In rapld pyrolysis XYo2 Matsuo, Y. et al., Coal Sci. TechnoL, 1995, 24, 929-932. Describes a study of rapid pyrolysis of a brown coal under atmospheric pressure. The structure of mIcropores of char was investigated by a molecular probe method and compared with that of slow pyrolysis char. Discusses the effect of heating rate on microporous character of the char in connection with the distribution of gaseous and liquid products in pyrolysis.

The rate of temperature rise of a rubbltumlnous 96106396 coal during spontaneour combustion In an adlabatlc device: The effect of moisture content and drying methods Vance, W. E. el al., Combustion & Flame, Aug. 1996,106, (3), 261-270. The work investigates the effect of the moisture content of coal on its spontaneous ignition in oxygen. It has been found that the highest heating rate is achieved at a medium moisture content of approximately 7 wt% for an initial inherent moisture content of the coal before drying of approximately 20 wtl. This is particularly noticeable at temperatures below 80°C and tends to support previous studies showing that a maximum oxidation rate occurs at such a moisture content in the same tern rature ran e. Two drying methods have been adopted in the current worp and the effects of their operating conditions on the heating rates are described. 96106396 ;t$ll;tlons:

Response of a lamlnar premixed flame to flow A klnematlc model and thermoacoustlc lnetablllty

Fleifil, M. et al., Combusrion & Flame, Sep. 1996, 106, (4), 487-510. Combustion instability is a resonance phenomenon that arises due to the coupling between the system acoustics and the unsteady heat release. The co&u&e feedback t&veen the two processes, whicli is known to occur as a certain phase relationship between the pressure and the unsteady heat release rate IS satisfied, depends on many parameters among which is the acoustic mode, the flame holder characteristics, and the dominant burning pattern. In this paper, the authors construct an analytical model to describe the dynamic response of a laminar premixed flame stabilized on the rim of a tube to velocity oscillation. Considers uniform and nonuniform velocity perturbation superimposed on a pipe flow velocity profile. The role of hyslcal factors In mass transport and 96106397 phase tranrformatlon In Pntergranular melts durlng coal ash slnterlng and deposit deformatlon Nowok, J. W. et al., Prepr. Pap.-Am. Chem. Sot., Div. Fuel Chem., 1996, 41, (2), 676-680. The a r discusses the role of hysical properties of melts such as viscosity, I$ slon, ’ and surface-inte Kacial tensions in sintering and deformation mechanisms of ash deposits above the glass transformation temperature. The DTA technique was applied to measure glass transformation and crystallization temperatures. Semi-coke of hlgh speed brown coal pyrolysis as 96106396 component of coal blends for coking process and fuel for lnjectlon Into blast furnaces Shkoller, M. B. ef al., Coal Sci. Technol., 1995, 24, 1049-1052. To upgrade low-ash, low-sulphur coals of the Kansk-Achinsk brown coal basin, a method for rapid pyrolysis resulting in production of powdered semicoke (BCS), tar and gas has been developed and realized on full-scale basis in Russia. BCS influences the formation of bulk density of coal blends, plastic mass, hysical-mechanical and physical-chemical propeties of coke as an active Pcaning additvie. Slmulatlon and moderation of the thermal 96106399 response of conflned preosed explosive composltlons Dagley, I. J. et al., Combustion &Flame, Sep. 1996, 106, (4), 428-441. The effects on the thermal response of pressed polymer bonded explosives caused by varying their components have been assessed at two extreme heating rates using the Super Small-scale Cookoff Bomb. Tests were primarily conducted on RDX-based compositions containing 5% ethylenevinyl acetate binder with varying amounts of PETN or TATB. Some ex riments were numerically simulated using a one-dimensional finite cl1 .$ference code. 96106400 Simultaneous behavior of pulverized coal char combustion and fine Iron oxide reduction by Injecting the mlxture of coal char and Iron oxide Kang, S. M. et al., ISIJ Int, 1996, 36, (2), 156-163. Describes the simultaneous behaviour of combustion of pulverized coal char and reduction of fine iron ore by using a laboratory-scale tube furnace.

450

Fuel and Energy Abstracts November 1996

WO6403 Slagging behavior of peat ash Heikkinen, R. et al., Prepr. Pap.-Am. Chem. Sot., Div. Fuel Chem., 1996, 41, (2), 667-671. Presents a study of slagging behaviour of five peat sam les. The slagging indexes developed for coal are not suitable for the pre d!action of slagging ak ash due to the very low sulphur content of each peat behaviour Ofsp” sample. The aggmg index does not carry information even on a relative slagging tendency. Solids preparation and handling (In pressurized 96106404 fluldlzed bed combustion1 Wardell, R. V. Pressurized &id. Bed Cornbust., Blackie, Glasgow, UK, 1995, 135-163. Discusses the solids preparation and handling in pressurized fluidized bed combustion including lock-hopper systems, coal-water mixtures feed systerns, and fuel injection into combustors. QYO6405 Species measurements In a hypersonic hydrogena/r, combustion wake Skinner, K. A. and Stalker, R. J. Combusrion & Flame, Sep. 1996, 106, (4). 478-486. A continuously sampling, time-of-flight mass spectrometer has been used to measure relative species concentrations in a two-dimensional, hydrogenair combustion wake at mainstream Mach numbers exceeding 5. The experiments in a free piston shock tunnel, yielded distribution of hydrogen, oxygen, nitrogen{ water, and nitric oxide at stagnation enthalpies ranging from 5.6 MJ kg’ to 12.2 MJ kg” and at a distance of approximately 100 times the thickness of the initial hydrogen jet. Stabilization of premixed flames on rotating Bun96/06406 sen burners ($;,qJj7L and Sohrab, S. H. Combustion & Flame, Sep. 1996, 106, (4)

The effect of rotation on stabilization of methane-air premixed Bunsen flames is experimentally investigated. Both the flame blowoff and flashback contours are deteimined in the fuel mole fraction versus Reynolds number plane with the rotational Reynolds number Re, as a parameter. 96/06407 Stochastic description of premixed turbulent combustlon In terms of a coarse-gralned flame surface density Fedotov, S. P. Combustion & Flame, Sep. 1996, 106, (a), 369-376. The problem of premixed turbulent combustion has been formulated in terms of a stochastic differential equation for a coarse-grained flame surface density (FSD). A closed equation for the one-point probability density function (PDF) for FSD has been derived, using the functional derivative technique, together with the assumption that thi convection velocity and flame stretch are homogeneous, isotropic, Gaussian random fields with many spatial scales and rapid oscillations in time. It has been shown that in the homoeeneous case. the stationarv PDF can be obtained analvticallv. It has been demonstrated’that the mosi probable value of FSD that is priferentially observed in an experiment might be considerably different from its ensemble mean value. This observation suggests that the turbulent combustion cannot be generally characterized by the mean value of relevant parameters. 96/06406 A study of onllne analysis of chlorine durlng coal combustion Napier, J. et al., Prepr. Pap.-Am. Chem. Sot., Div. Fuel Chem., 1996, 41, (1). 51.55. The paper discusses the behaviour of chlorine during the combustion of coal using TG-FTIR and TG-MS systems. Parameters of the coal samples studied included variations in chlorine content, rank, and mesh size.