11 Process heating, powef end incineration (energy applications in industry)

11 PROCESS HEATING, POWER AND INCINERATION

Energy Applications in Industry

se/91 993 Analysis of drsorptlon and dlffualon durlng srcon- dary drylng In vaccum frerzadrylng of hydroxyethyl starch i Fle& G. 5. .

et al., Chemical Engng. & Process., Aug. 1995, 34, (4),

Freeze-drying is a common process for the long-term preservation of biochemicals derived from aqueous solutions. One of the important factors involved in a successful freeze-drying procedure is the secondary drying step. The effect of temperature and ptes&re on water mass transport during the secondary drying stage has been examined for concentrated, a ueous solutions of hydroxyethyl starch, a stabilizing agent common on the 8 eexe- drying of biological material. Desorption equilibria were reached after evacuation of 5-Ed. The importance of these results for a comprehensive understanding of the freexe-drying process, efficient design and final prod- uct quality are emphasized.

%I01 a94 The a external P

pllcatlon of a variable-area Jet pump to the reclrculat on of hot flue-gases

Priestman, G. H. and Tippet& J. R. 3. Inst. of Energy, Dec. 1995, 68, (477), 213-219. A jet pump of special design, having a variable-geometry nozzle, is applied to the external recirculation of flue gas in a furnace system. This new concept improves reliability by eliminating the need for a flue-gas fan. and enables the recycle of high-temperature gas to be affected. Recycle is induced by simply increasing the main air supply pressure by a reasonably modest amount, while the nozzle area of the jet pump is reduced by the progressive insertion of a co-axial spear. Details are given of the jet pump &sign. A model of its o

r rating characteristics is given, which modifies

standard incomoressible- ow iet oumo such that it can be aoolied to the large nozzle : mixing-tube at& &tio designs require for thii ‘application. The model is used to predict the jet pump’s operating charactertstics and the potential performance envelope. of a flue-gas recirculation system.

96lQl695 Blast-furnace smelting wlth carbon redlatrlbutlon for direct reduction Danaev. N. T. et al., St&, 1995. (2), B-11. (In Russian) Discusses the possibility of increasing the coke efficiency in blast furnace smelting of ig iron by using coke breeze of 1040 mm particle size was demonstrate . x

99iOl a96 Calculation method of monltorlng coal conaump- tlon In a blast furnace Babarykin, N. N. St&, 1995, (a), 16-20. (In Russian) A calculation method for the determination of the optimum amounts cf pulverized coal injection into an ironmaking blast furnace, based on ther- modynamic data, 1s proposed.

%I01 997 The character of ash depoalts and the thermal per- formance of furnaces Wall, T. F. et al., Fuel Process TechnoL, 1995, 44, (I), 143-153. The character of fireside ash deposits depend on the processes by which deposits are formed and subsequent reacttons within the deposit and with furnace gases. The properties influencing furnace heat transfer, absorptiv- ity for radiative transfer and thermal conditivity for conductive transfer are shown from many measurements to depend on this character. Ilhrstrative trends in these properties as deposits mature and grow are presented together with theta effect on furnace exit temperature and efficiency.

99lQl999 Coherent vortlcer In thermally atratlfled and rotat- Ing turbulence M&,6O. and Lesieur, M. Int. .I. Heat & Fluid Flow, Oct. 1995, 16, (5),

Developed turbulent 50~s contain coherent vortices of various sixes, which play a major role in heat and mass transfer processes. Presents results of direct and large-eddy simulations LES focusing on the role

P J layed b these coherent vortices. Describes in detail the formalism of arge-cd y simulations of turbulence, with a family of models developed

on the basis of Rraichnan’s eddy-viscosity, and see, for example, how longitudinal hairpin vortices are taken into account within these LES. Dis- cusses vortex structure identification. Results are presented concerning large-scale intermittency of a passive temperature and the role played by a stable-stratification to reduce this intermittency.

%I01 899 Corn egy In a wall-fire 8

utatlonal modelllng of a alag-reduction atrat- furnace

Mann, A. P. et a& J. Inst. of Energy, Dec. 1995,68, (477). 193-198. Wall-slagging is a serious problem faced by many furnace operators. It reduces heat-transfer to furnace walls, and consequently furnace efficiency. At CaRide B power station in Queensland, Australia, the problem was exacerbated by high-iron coals, which tend to form slag easily. and it drove a combined experimental and computational study into the causes of slag build-up. Using details of the 5ow pattern leading to slag formation obtained from numerical modelling, operators proposed a range of possible modifications. One proposal was to reduce neat-wall temperatures by introducing an air-curtam along one of the affected walls; the aircurtain modification could be evaluated by means of a computer model to predict the effect on near-wall gas temperatures and particle-wall impacts.

%lQlQ% Developments In Iron and steel makln Zervas. T. et al., Inr. J. Energy Research, Jan. 1996. 20,, 1). 69-91. 2 A sutvey is presented of the direct reduction processes whtch are presently in wmmerctal operation for the production of iron and steel as an altema- tive to the classical blast furnace route. The relative advantages and disad- vantages of each technology are presented and their relative energy efficiencies discussed.

%I01901 Effect of coal duat fuel on heat tranafer in the tuyere zone of a blast furnace Yaroshevaskij. S. L et al.. Izv. Vyssk Uchebn. Zaved, Chern. Metall., 1995. (1). 14115. (In Russian) - The pulverized coal injection in ironmaking blast furnaces decreased the theoretical temperature of combustion in the tuyere zone by 3545”. The normal temperature of the metal can be reached at lower temperature of gases in thetuyere zone due to better heat transfer conditions. Gives exper- imental data for the correlation between the amounts of injected coal and temperature conditions in the tuyere. zone.

96/019% Effects of alnglarow, B

ull-wing baffler on the performance of a annularly-f nned tube heat exchenger

Keamey, S. P. and Jacobi, A. M. I#. J. HKACandR Res., Oct. 1995, 1, (4). 257-272. The paper describes ex riemnts directed at measuring the heat transfer and pressure drop

/T ormance of gull-wing baffles as a method for

enhancing heat exe anger performance. Uses local convective data to explain the 5ow and heat transfer interactions.

96lO1903 Embedded vortlcea In Internal flow: heat transfer and pressure loss enhancement Fiebig. M. Int. J. Heat & Fluid Flow, Oct. 1995, 16. (5). 376-388. Vortices depend strongly on the way they are. generated. A class of wing- type vortex generators, which can easily be into

r rated into heat transfer

surfaces, is considered in fully developed and eveloping channel 50~s with respect to heat transfer enhancement and pressure loss configurations have been investigated in detail by the researc r

nalty. Such group ‘Vor-

tics and Heat Transfer’ at the ITF of the Ruhr University. Three enhance- ment mechanisms are identified and discussed quantitatively.

96lQ1904 hydraullcs

Englneerlng appllcatlon of pneumatics and

Turner, I. C. Arnold 338 Euston Roaci, London NW1 3BH, f14.991995, 192 pp. The book has been written in collaboration with the Institution of Plant Engineers.

96lQI905 Experlmental and computatlonal stud r

of turbulent heat transfer characterlstlca In serrated channel f ow Obi, S. et al., Int. J. Heat & Fluid Flow, Oct. 1995, 16, (5), 398404. A two-dimensional (2-D) channel with a serrated wall is proposed as a device for heat transfer aumnentation. Measurements of the 5ow velocitv in the whole field as well & of the heat transfer coefficient along the w& are undertaken for two different channel heights. The same 5ow fields are calculated using a second-moment closure and the standard k-e model.

QSlQl906 First- and second-law analyala of energy recov- erlea In blast-furnace regeneratora Bisio, G. Energy, Feb. 1996, 21, (2). 147-155. Examines various systems for the recovery of thermal energy from waste gases and for preheating in blast-furnace Cowpet stoves, with the basic aim of improving efficiencies when utilizing blast-furnace gas with low net heating value at constant peak temperature. Using fiit- and second-law analyses, with suitably defined exetgetic quantities, numerical values are given to measure energy savings.

96101907 Flow bolllng of a hlghly vlscour pseudoplastlc fluld In vertlcal tubes $51yg: L et al., Chemical Engng. & Process., Aug. 1995, 34, (4),

Presents an experimental study of 5ow boiling heat transfer to a highly viscous fluid in vertical downward flow.

Fuel and Energy Abstracts March 19% 129