摘要:

AbstractFlow pattern was visually observed for non‐foaming and foaming Newtonian and non‐Newtonian liquids under concurrent downflow with air in packed beds using different configurations of column geometry and packins. Flow maps delineating the different flow regions were presented based on the present study as well as that of earlier investigations. The total and dynamic liquid saturation were experimentally measured and correlations were presented in terms of (i) the Lockhart‐Martinelli parameter, χ, and (ii) the flow var

ISSN:0008-4034    

DOI:10.1002/cjce.5450660301

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

年代:1988

数据来源: WILEY

摘要:

AbstractLaminar mixed convection in the entrance region of shrouded arrays of heated rectangular blocks is approximated numerically for large Prandtl number fluids. The problem considered is related to the convective cooling of electronic components mounted on horizontal circuit boards. Two heating conditions are investigated; in case 1, the uniformly heated components are facing upwards and, in case 2, the heated components are facing downwards. Typical fluid streamlines and isotherms, block wall temperature distributions and local Nusselt numbers are presented. It is found that the secondary flow leads to a significant enhancement in heat transfer for cases where the block faces upwards rather than downwards.

ISSN:0008-4034    

DOI:10.1002/cjce.5450660302

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

年代:1988

数据来源: WILEY

摘要:

AbstractA heat transfer model that accounts for both gas and liquid phase resistance was developed for sieve trays where the overall heat transfer coefficient is expressed as a function of Sauter‐mean bubble diameter. These diameters, obtained from pilot plant data, were correlated and used to predict point efficiencies on production plant trays. Applying the appropriate liquid flow distribution model allows the prediction of overall tray efficiencies. Predicted temperature profiles have agreed well with measured plant profiles and tray changes at the production plant have resulted in steam savings that were adequately predicted by the mode

ISSN:0008-4034    

DOI:10.1002/cjce.5450660303

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

年代:1988

数据来源: WILEY

摘要:

AbstractDistillation of water has been investigated in packed columns of 300, 500 and 750 mm diameter. Both ordered packings (Goodloe, Mellapak and Sulzer CY) and random packings (Hy‐Pak, Mini‐ring and Pall‐ring) were studied and performance compared. It was found that, with surface treatments, phosphor bronze packings show good performance and insignificant scale‐up factors. Plastic materials are not suitable for water distillation because of their poor wetting characte

ISSN:0008-4034    

DOI:10.1002/cjce.5450660304

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe kinetics of heavy mineral and bitumen recovery from oilsand tailings are presented. The results show that the recovery rates for titanium, zirconium and bitumen were affected by addition of surfactants Tretolite F46 and E3453. Recoveries were a function of time and of the minerals and bitumen present.

ISSN:0008-4034    

DOI:10.1002/cjce.5450660305

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe process of hot water extraction of tar sand was modified and adapted for removal of heavy oil from bottom tank petroleum sludges, and was submitted to a laboratory feasibility study. This process can also be utilized to clean beach sands contaminated by accidental heavy oil spills.In the case of oil contaminated sands, a single stage extraction has yielded a 99% recovery of hydrocarbons and clean sands (containing less than 0.1% of hydrocarbons) which are thus safe to be returned to the environment.In the case of petroleum bottom tank sludge, it was necessary to proceed with a double stage extraction with the addition of a wetting agent. A dosage of a Na2Si O3aqueous solution of 1% by weight has proven efficient, allowing an 82% recovery of hydrocarbons, with only 0.5% of hydrocarbons content in the solid residues.

ISSN:0008-4034    

DOI:10.1002/cjce.5450660306

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe effect of cationic, anionic and neutral surfactants on the mechanical dewatering of a highly decomposed fuelgrade peat has been examined. Surfactant adsorption and zeta potential of the peat particles correlated with dewatering of peat samples. The cationic surfactants had large positive effects on dewatering, the anionic surfactants had a negative effect while the neutral surfactant had no effect. The effects of the surfactants could be explained by charge neutralization and double layer suppression. The cationic surfactants were superior to analogous organic salts because of enhanced interaction by the hydrophobic effect.

ISSN:0008-4034    

DOI:10.1002/cjce.5450660307

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe phase inversion of a polymeric solution is modeled assuming the validity of the diffusion equation and the existence of a mass‐cumulative stagnant film of vapor on the cast membrane. Unlike previous analyses, the model predicts a maximum in the evaporative flux leaving the polymeric solution. A comparison of theory with experiments indicates that the solvent flux is predicted only qualitatively. The discrepancy is probably due to some assumptions introduced, for mathematical tractability, in the mode

ISSN:0008-4034    

DOI:10.1002/cjce.5450660308

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

年代:1988

数据来源: WILEY

摘要:

AbstractKinetics of reactions involved in pyrolysis of cellulose has been modeled in terms of a three reaction model. In this model it is assumed that cellulose decomposes to tars, chars and gaseous products via three competitive first‐order reactions. Arrhenius parameters have been obtained to describe the rate constants of these reactions. The three reaction model predicts the weight loss data reasonably well. Product yields of tars, chars and gases predicted by the three reaction model are compared over the temperature range 250 to 360°C. In this communication a technique for analyzing experimental data of a solid state reaction is present

ISSN:0008-4034    

DOI:10.1002/cjce.5450660309

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

年代:1988

数据来源: WILEY

摘要:

AbstractAt temperatures below 300°C, it has been shown that the pyrolysis of cellulose can be modeled in terms of a modified Kilzer‐Broido ((K‐B) Model. According to this model, cellulose decomposes via two competitive reactions, a dehydration reaction to form anhydrocellulose and a depolymerization reaction to form levoglucosan. Anhydrocellulose later decomposes to chars and gaseous products via two competitive reactions. Arrhenius parameters and a technique of estimating empirical constants from experimental data for the K‐B type reactions are presented. Comparison of the ability of the modified K‐B model and the three reaction model to predict weight loss, product yields and heat pretreated results are a

ISSN:0008-4034    

DOI:10.1002/cjce.5450660310

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

年代:1988

数据来源: WILEY