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09 Combustion burners, combustion

systems)

95109320

Flnlte-rate chemistry and transient effects In direct

numerlcal slmulatlonr of turbulent nonpremlxed flames

Mahalingam, S. et al.,

Combusrion & Flame, Aug. 1995, 102, (3),

285-297.

Three-dimensional direct numerical simulafions (DNS) of turbulent non-

premixed flames including finite-rate chemistry and heat release effects

were performed. Two chemical reaction modils were considered: (1) a

single-step global reaction model in which the heat release and activation

energy parameters are typical of combustion applications, and (2) a hvo-

step reaction model to simulate radical production and consumption and to

compare against the single-step model. The model problem consists of the

interaction between an initially unstrained laminar diffusion flame and a

three-dimensional field of homogeneous turbulence. Conditions ranging

from fast chemistry to the pure mixing acting limit were studied by varying

a global Damkohler number.

:::::6

Increased CO productlon by fuel leakage In

Van Der Meu, T.

Flemish)

Gus (Nerherlands), Sep. 1995, 115, (9), 40-41. (In

In domestic gas appliances .fuel is sometimes spilled by local blowoff of

flames or since they are not adequately stabilised on the edge of the burner.

These side effects m ay cause. unwanted extra carbon mono xide and meth-

ane emissions. With the use of laser technology Gasunie examined two

commercial burners. Increased CO production WIISndeed demonstrated. It

was found that raised CO formation does not necessarily imply raised CO

emissions.

95106321

Flamrlet structure of radlatlng CH,-air flames

Chan, S. H. et al., Combustion Fl ame,

Sep.

1995, 102, (4), 438-446.

The structure of radiating laminar flamelets of CH,-air diffusion flames is

presented. Radiative heat transfer effects are examined by using the opti-

cally thin and full radiation models. The predictions are based on the solu-

t ion of a one-dimensional set of conservation equations with the mixture

fraction, f, as the independent variable for different fixed values of tbe

scalar dissipation rate, X. A reduced three-step c

emical kinetic mecha-

nism is used for the whole range of f. The results o the numerical compu-

tations yield values of the temperature and main s

ties for different

values of X until extinction of the flamelet

p”ventual y occurs. Both the

adiabatic flamelet and nonadiabatic flamelet with radiative heat loss are

studied and their respective flamelet structures are presented. Good agree-

ment is obtained with limited experimental data available.

95106322

Flammablllty llmlt and limit-temperature of counter-

flow lean methane-air flames

:x_:~:

H. and Sohrab, S. H.

Combustion &

Ffume,

9~1. 1995, 102, (l),

95106323 Fluldlzed-bed apparatus for generating steam In

coal combustion

(Assigned ro) Fosrer Wheeler Energy Cor p., JAP. Par.JP.67,34,074, Feb.

1995.

96106324

Furnace for carbonlzatlon of waste solids, e.g.,

woods and tires

Maezato, T. (Assigned ro) Maezaro Toshio, JAP. Par. JP.O7,?1,255, Jan.

1995.

95106325

High-tern

P

erature sulfur removal under fluldlzed

bed combustion cond tlons - A chemical Interpretation

Makarytchev, . V. er al.,

Chem. Eng. Sci., 1995, 50, (9), 1401-1407.

Describes theoretical and exoerimental studies carried out on coal sulnhur

removal under chaotically ihanging oxidizing and

reducin nditions,

which occur in the dense zone of bubbling fluidized beds.

p xperimental

desulphurization trends were analyzed by comparison with multi-species

(50 gas-phase, 7 solid-phase species) equilibrium calculations for

&al/sTear&orbent/air system. It was shown, ihat under fluctuating reduc-

ing/oxidizing conditions, sulphur capture as CaS in locally reducing zones

increased the sulphur retention level of the sorbent.

As

a chemical interpre-

tation, a time history of sorbent particle calcination-sulphation is proposed,

which leads to the formation of a particle structure with a sulphided (CaS)

core and a sulphated (CaSO,) shell.

95106329

Influence of the flnenera of coal snd llgnlte on the

flame formatlon In rotaw cement kllnr

Seidel, G. ZKG In r., 1995,:48, (l), 18-21 . (In German)

Discusses the influences of the fineness of tzrindin a of medium- and hi&

volatiles pulverized coals for cement rota+ kilns.-Describes a method-of

evaluating fuels developed with the aid of a mathematical model which is

tailored to the particular requirements of the clinker combustion process.

95106330

Integrating low-NO, burners, overflre air, and relec-

tlve noncatalytic reduction on a utlllty coal-flred holler

Hunt, T. er (11.:

Environ. Prog., 1995, 14,<2), 115-120.

Describes an integrated dry NOdSO, emissions control system which com-

bines low-NO, burners, overfire air, selective noncatalytic reduction and

dry sorbent injection with humidification to reduce by up to 70 both NO,

and SO, emissions from a 10 0 MW coal-fired u tilitv boiler. Th e oroiect is

being carried out at the Public Service Co. of Colorado’s Ara

Denver, Colorado as part of the DOE’s clean coal

programme.

95106331

lnvlacld Isothermal rwlrllng flow In the expandlng

quarl of Industrial burners

Yeh, H. M. and Yang, S. C.

Energy, Sep. 19 95, 20, (9), 889-895.

Equations for predictions of stream functions and velocity profiles in iso-

thermal, inviscid swirling flow through .the expanding quarl of ind ustrial

burners with a bluff body have been derived with the aid of a correlation

equation obtained from experimental data. The loci of zero axial velocit

obtained from this correlatron are somewhat different from those observe

d

whereas the stream lines have reasonable profiles. Although results derived

for inviscid flow cannot be used lo predict the flowfield precisely, the

correlation may be helpful in describing the general behaviour of swirling

flow.

95106332

Ironmaklng. 10. Prolongatlqn of the Ilfe of blast fur-

naces and coke ovens

Akimoto, E. and Tanino, M.

Tersu

to Hagane, 1995, 81, (4), 279-282.

(In

Japanese)

Discusses refractories, cooling apparatus, iron skins, and furnace repair

techniques in relation to prolonging the life of blast furnaces as well as the

diagnosis and repair techniques in prolonging the life of coke ovens.

95106333

lronmakln

. 6. Control of burden dlatrlbutlon and

realization of oreclae b ast-furnace

ooeratlon

Inada, T. Ters; to Hugane, 1995, 81, (4), 268-271. (In Japanese)

Describes the bell-less burden distribution technique, central loading tech-

nique of coke, and distribution control.

95106334

Ironmaklng. 7. Development of pulverlzed coal

InjectIon PCI) technology

Inaba, S. ?ers; to HaganeT-1995, 81, (4), 271-273. (In Japanese)

Discusses the amount of pulverized coal injection, fine-grained coal injec-

tion, and future research problems.

95106326

lgnltlon slmulatlon of methane/hydrogen mlxturer

In a supersonlc mlxlng layer

Ju, Y. and Niioka. T. Combustion & Flame. Seu. 1995 . 10:. (41.4 62-47 0.

Ignition of methaheihydrogen and air streams in’s supe;sonic .m’ixing ayer

was investigated numerically with the C-l chemistrv for interests in aero-

space application. Attention-was paid to ignition deiay times and ignition

processes with the addition of methane to hydrogen and the addition of

hydrogen to methane involving elementary reactions. In the first case,

results showed that the addition of methane to hydrogen and a reaction

competition stage, were identified.

95106335

Klnetlc parameters of composite propellanta from

95106327

The lncorporatlon of nitrogen Into Isotropic car-

bons and Its release durlna temDerature-DroPrammed

combuatlon

Zhu, Q. er al., CarboQ 1995, 33, (l), 35-46.

‘\ -

thermogravlmetrlc data

. .

Rao, V. K. er al., Combustion F lame, Jul. 1995, 102, (l), 219-225.

The paper presents a method of estimating all three global kinetic parame-

ters A, E, and n from the results of a single dynamic (nonisothermal) TG

run on a propellant sample. The procedure will also show how satisfacto-

rily pyrolysis of the propellant can be represented by the simple relation of

Eq. 4 with constant values of A, E, and n.

95106336

Low-temperature combustion: Automatic genera-

tlon of primary oxldatlon reactlona and lumplna procedurea

Ranzi, E. et al., Combusrion Fl ame, Jul. 1995 ,.102, (l), 17 9-192 .

The aim of this paper is to present some general rules for the automatic

generation of primary oxidation reactions of large hydrocarbon fuels. The

proposed approach is applied to n-paraffins for reason of simplicity. N ever-

thless, the final goal is to feed the tested rules and kinetic parameters into a

more general and effective expert system for the generation of primary

mechanisms of real mixtures containing heavier branched hydrocarbons.

The environmental impact of coal utilization is a major problem for a

variety of reasons, for example, acid rain, emission of ‘greenhouse’ gases,

etc. Coal combustion is a major contributor to acid rain due to the emis-

sions of NO, and SO,. The objective of this study was to investigate the

role of active sites and the effect of nitrogen functlonalities on nitric oxide

release during combustion, using isothermal and temperature-programmed

combustion of model carbons.

Fuel and Energy Abstracts November 1996 447