摘要:

AbstractVolatile oil markets experienced in the seventies have promoted renewed interest in coal‐based fuel technologies. Coal‐slurry fuels have emerged as viable technical alternatives for oil and gas in utility and industrial boilers. Despite current low prices and the abundance of oil, concerns over its long‐term availability and price, as well as strategic considerations, make coal‐slurry technology attractive. Initially, coal‐slurry fuels were based on coal‐oil mixtures, now the emphasis is largely on coal‐water fuels.This review assesses the status of the relevant technology. It covers the preparation of coal‐slurry fuels, slurry properties, combustion characteristics, emissions, current applications and concludes with their

ISSN:0008-4034    

DOI:10.1002/cjce.5450650201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe breakup of non‐Newtonian emulsion jets into drops was experimentally studied by ejecting both O/W and W/O emulsions vertically downward into stagnant air through nozzles. Breakup lengths of non‐Newtonian emulsion jets were found to be almost equivalent to those of Newtonian jets. Experimental breakup data establish that the static surface tension of the oil phase can be used as the surface tension of W/O emulsion jets, whereas the dynamic surface tension of aqueous surfactant solutions is used as that of O/W emulsion jets. Diameters of drops formed from non‐Newtonian emulsion jets are in good agreement with the prediction from the stability theory previously developed by the authors. When the rheological index in a power law model is appreciably smaller than unity and the Ohnesorge number is significantly large, however, drop sizes are larger than the prediction because of the profile relaxation in jets. The critical velocity of emulsion jets, either O/W or W/O emulsion, is significantly lower than that of homogeneous Newtonian

ISSN:0008-4034    

DOI:10.1002/cjce.5450650202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe decay of a dense dispersion formed under calm conditions is given by\documentclass{article}\pagestyle{empty}\begin{document}$$ h^{1/2} = h_a^{1/2} - \frac{1}{2}\left( {\frac{{g\phi _o }}{K}} \right)^{1/2} \left( {\frac{{\Delta \rho g}}{\sigma }} \right)^{1/4} t $$\end{document}Experiments in a batch vessel with different liquid‐liquid systems and initial drop diameters show that the dimensionless constantKis equal to 26,000. This agrees with the value previously determined from the variation in steady‐state dispersion height with throughput in spray columns, the analogous equation being\documentclass{article}\pagestyle{empty}\begin{document}$$ H = \frac{K}{{g\phi _o }}\left( {\frac{\sigma }{{\Delta \rho g}}} \right)^{1/2} \left( {\frac{{Q_d }}{{A\bar \in }}} \right)^2 $$\end{document}The results can thus be used to predict the height of the dispersion formed in the disengaging section of extraction colu

ISSN:0008-4034    

DOI:10.1002/cjce.5450650203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractA new apparatus, the inverse fluidized bed biofilm reactor, is described. Introduction of the so called inverse fluidized bed, in which low density particles covered by a biofilm are fluidized by downflow of the liquid, allows control of the biofilm thickness and provides a high oxygen concentration in the reacting liquid. Characteristics of the reactor were studied by carrying out two important biotechnological processes: aerobic wastewater treatment by a mixed bacterial culture, and ferrous iron oxidation by the bacteriaThiobacillus ferrooxidans.The bioreaction rates per unit volume of the reactor were up to 14 times higher than those in the equivalent airlift bioreactor. The structure of the liquid flow was determined by a tracer method.

ISSN:0008-4034    

DOI:10.1002/cjce.5450650204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractA new correlation is proposed for the heat transfer coefficient between an immersed horizontal tube and very shallow fluidized beds (static bed heights of 10‐40 mm). The correlation is based upon experimental data obtained in this work for a horizontal tube with an outside diameter of 13.1 mm, immersed in beds of spherical alumina particles with mean particle sizes of 335‐1261 microns. The maximum bed pressure drop was 92.5 mm water. The effects of tube elevation, static bed height and distributor design were investigated. Nine different distributors were used, with maximum pressure drops ranging from 3 to 800 mm water and open areas from 2.2 to 36%. A comparison between the proposed correlation and data reported in the literature showed an agreement of approximately

ISSN:0008-4034    

DOI:10.1002/cjce.5450650205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractParticle‐liquid mass transfer in a co‐current three‐phase fluidized bed of glass beads, water and air was studied with two measurement techniques. Both techniques measured the weight loss of a few particles coated with benzoic acid in a bed of inert glass beads. The effects of liquid and gas velocities, gas distribution and surface active agents on particle‐liquid mass transfer in a three‐phase fluidized bed were thus determined. In the absence of surface active agents in the liquid, particle‐liquid mass transfer rates in a three‐phase fluidized bed were up to 30% higher than in the corresponding liquid fluidized bed. When surface active agents were added to the liquid, the particle‐liquid mass transfer rate was increased by up to about 100% in the three‐phase fluidized bed, relative to the liquid fluidized bed. The particle‐liquid mass transfer coefficient was found to be inversely proportional to the liquid hold‐up in the thre

ISSN:0008-4034    

DOI:10.1002/cjce.5450650206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractLe travail étudie expérimentalement le transfert de matière liquide‐paroi en présence d'un écoulement biphasique (solide‐liquide ou liquide‐liquide) dans un espace annulaire cylindrique avec rotation du cylindre intérieur et débit axial (écoulement de Couette‐Taylor‐Poiseuille). L'existence d'une phase dispersée maintient le régime d'écoulement‐constitué par le mouvement axial de cellules tourbillonnaires toroïdalesNdashsur un domaine hydrodynamique beaucoup plus étendu que dans le cas d'un écoulement monophasique. Les coefficients de transfert de matière augmentent de manière très sensible avec la présence d'une phase disperséde; cette augmentation est měme importante (de 60 à

ISSN:0008-4034    

DOI:10.1002/cjce.5450650207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractAn equation for the diffusion of solute molecules in pores filled with liquids has been developed. It has been found to represent the diffusion of a variety of materials, from simple molecules to fractions of petroleum asphaltenes.

ISSN:0008-4034    

DOI:10.1002/cjce.5450650208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractA two‐stage evolutionary method is developed to synthesize an optimal energy integrated distillation separation process: the search of the separation sequence, and the introduction of energy integration to the given separation sequence. For the former an evolutionary procedure first generating initial separation sequences and then evolving them is developed. For the latter an evolutionary procedure, first indicating the direction of the evolution by the thermodynamic analysis and then estimating it based on the objective function, is developed. An example problem of a five‐component separation demonstrates the effectiveness of this proposed met

ISSN:0008-4034    

DOI:10.1002/cjce.5450650209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractDeuterium transfer rates between water vapour and hydrogen gas have been obtained for platinized carbon powder (Pt‐C) and Teflon wetproofed platinized carbon films. The pore diffusional resistance in the catalyst films was assessed by calculating the effectiveness factor, ϵ, from a mathematical model for simultaneous diffusion and first order reversible reaction kinetics. Wetproofing the Pt‐C catalyst with Teflon increased the intrinsic rate of reaction, but the effectiveness factor decreased with increasing catalyst layer thickness. Pore size and surface area distributions and water vapour adsorption isotherms of the Pt‐C/Teflon catalyst films were similar to those of the Pt‐C itself. Since Teflon had negligibly small surface area and very large pores compared to the carbon support, wetproofing did not cause significant changes to the physical characteristics of the platinize

ISSN:0008-4034    

DOI:10.1002/cjce.5450650210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY