摘要:

AbstractSelf‐Cycling Fermentations rely on the accurate control over reactor volume to achieve consistent results for many successive cycles. Previous methods using separate vessels for measuring both harvested broth and nutrient supplements have the disadvantage of causing cumulative volume error in the reactor. This work describes the performance of a new control system based on the continuous monitoring of the combined weight of reactor and contents. Results indicate that during the growth ofBacillus subtilisATCC 10774, cycle periods with an average variation of less than 7% can be achieved for at least 77 consecutive generations of cells. The success of the control system was further demonstrated by evidence for the partial synchrony of cell divisio

ISSN:0008-4034    

DOI:10.1002/cjce.5450710312

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

年代:1993

数据来源: WILEY

摘要:

AbstractInvestigations into the product recovery step of the extractive ethanol fermentation through partition experiments for ethanol‐water‐Adolr̀85 NF ternary systems were undertaken. Experimental liquid‐liquid equilibrium data for this ternary system were compared with numerical predictions based on the UNIFAC method. The influence of salts on distribution coefficients for ethanol extraction was also examined. An improvement in extraction characteristics was observed for ternary systems with salts. Flash vaporisation was used to subsequently examine the effect of liquid‐liquid ternary compositions on vapour‐liquid partitioning. The UNIFAC model was found to be very useful for semi‐quantitative analysis of such liquid extrac

ISSN:0008-4034    

DOI:10.1002/cjce.5450710313

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

年代:1993

数据来源: WILEY

摘要:

AbstractWe present empirical models for calculating the viscosity of hydrocarbons and their mixtures, including with carbon dioxide, over a wide range of temperatures and pressures. The procedure is simple, will always yield a reasonable answer, and is surprisingly accurate for the fluids and conditions we have examined. Indeed, our model is more accurate than other models currently in use, including the much more complicated corresponding states methods. Further, in many cases, the model is completely predictive, requiring only the normal boiling point as input data. The predictive ability of the model is also tested with several petroleum mixtures.

ISSN:0008-4034    

DOI:10.1002/cjce.5450710314

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

年代:1993

数据来源: WILEY

摘要:

AbstractA previous viscosity‐temperature correlation (Puttagunta et al., 1992) is extended to include a pressure term and employed successfully in predicting the combined effect of temperature and pressure on the viscosity of Canadian bitumens and heavy oils.Predictions are made on new sets of data based on a single measurement of viscosity at 30°C and 101.3 kPa pressure; and the results show similar accuracy as obtained in the sets of data used in developing the correlation.The correlation yields an absolute average deviation between predicted and experimental viscosity of 4.79% and a correlation coefficient of 0.99 over a range of temperatures between 20 and 120°C and gauge pressures between 0 and 18

ISSN:0008-4034    

DOI:10.1002/cjce.5450710315

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

年代:1993

数据来源: WILEY

摘要:

AbstractTo apply iterative dynamic programming (IDP) to optimal control problems having a very large number of control variables the use of randomly chosen values for control at each grid point is required. To gain insight into the effect of the number of allowable values for control, the region contraction factor, and the number of grid points for the state vector to be used, computational results are presented for two nonlinear systems, one of which possesses numerous local optima.The reliability of obtaining the global optimum for the bifunctional catalyst blend optimization problem was found to be somewhat higher by using randomly chosen values for control rather than by choosing the control values over a uniform distribution. The global optimum is obtained even when a small number of allowable values for control at each grid point and a small number of grid points for the states are used. There is a wide range of the region contraction factor for which rapid convergence to the optimum is obtained. Also the number of grid points for the state can be very small without adversely affecting convergence to the optimum.

ISSN:0008-4034    

DOI:10.1002/cjce.5450710316

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe pressure drop, ΔPTP, was measured for two‐phase flow through screen‐plate bubble columns. Based on a statistical analysis, an empirical correlation of the present data was obtained which indicates that ΔPTPis dependent only on the liquid kinematic viscosity and screen hydraulic radius over the ranges of variables st

ISSN:0008-4034    

DOI:10.1002/cjce.5450710317

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

年代:1993

数据来源: WILEY

摘要:

AbstractCharacteristics of a reciprocating screen‐plate bubble column were experimentally determined with dilute alcohol solutions. Results show that the addition of ethanol up to the concentration of 0.8 wt% produces very large gas holdups and overall mass transfer coefficients, in comparison with conventional bubble columns. The plate agitation was shown to cause increases not only in the interfacial area “a” but also in the individual mass transfer coefficientkLwhen the speed of reciprocation was

ISSN:0008-4034    

DOI:10.1002/cjce.5450710318

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

年代:1993

数据来源: WILEY

摘要:

AbstractBubble characteristics and gas hold‐up were studied in a two phase (air‐aqueous CMC solution) bubble column provided with helical coils and straight tubes as internals. The effects of superficial gas velocity, rheological properties, and volume fraction covered by the internals, on gas hold‐up were studied. Hold‐up values determined directly and by simultaneous pressure drop measurements matched well. Enhancement of gas hold‐up values up to 55 per cent was achieved in systems using internals. The gas hold‐up results were also compared with the values obtained from correlations reported in the

ISSN:0008-4034    

DOI:10.1002/cjce.5450710319

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

年代:1993

数据来源: WILEY

摘要:

AbstractA numerical analysis of the laminar flow of a Newtonian fluid in the inlet section of a circular pipe has been carried out for a Reynolds number range of 0 to 500, employing a finite element based CFD code. A new flow phenomenon has been identified at low Reynolds numbers (<50), viz, the existence of a peak in the axial pressure profile at a small distance from the entrance. Existing correlations for the entry length are shown to be insufficient and a new correlation for the entry length is proposed.

ISSN:0008-4034    

DOI:10.1002/cjce.5450710320

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe performance of isothermal plug‐flow tubular reactors under periodic inlet concentrations is theoretically analyzed for improvement in yield for homogeneous consecutive reactionsA→B→Cwhich, under conventional steady‐state operation, show input multiplicities in the flow rate on the yield ofB. Two values of flow rate give an identical yield ofBunder steady‐state operation. For periodic operation, a rectangular pulse is assumed for the inlet concentration. It is shown in three numerical examples that under concentration forcing the yield is significantly different for these two inlet flow rates. Under periodic operation the larger value of flow rate gives a higher

ISSN:0008-4034    

DOI:10.1002/cjce.5450710321

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

年代:1993

数据来源: WILEY