摘要:

AbstractA new procedure for synthesizing process flow sheets and base‐case designs has been developed. The procedure is evolutionary in nature and proceeds through a hierarchy of decision levels, where more fine structure is added to the flow sheet at each decision level. Heuristics are used to obtain some of the structural elements of the flow sheet, and other heuristics are used to make some of the decisions required at the various decision levels. In many cases, no heuristics are available, so that process alternatives are generated. The analysis protion of the procedure has strong focus on the economic tradeoffs that are associated with the significant design variable

ISSN:0001-1541    

DOI:10.1002/aic.690310302

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractIn this paper a new method is presented which will enable engineers to select better heat‐integrated distillation systems quickly and easily. The key to this method is making the assumption thatQΔT, the product of the condenser or reboiler duty and the temperature difference between the reboiler and condenser, is constant for a single distillation task over a wide range of pressures. Using this assumption and the principles of multieffect distillation, a lower bound on the utility use for single distillation tasks and for distillation sequences is readily calculated for designs involving simple two‐product columns that may not be multieffected. This paper also describes methods which can be used to synthesize distillation systems which approach these bounds. Finally, an algorithm is presented which develops the least cost distillation system for separating a multicomponent feed. The methods in this paper are illustrated with a five‐component example p

ISSN:0001-1541    

DOI:10.1002/aic.690310303

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractIn Part I (Tsonopoulos and Wilson, 1983), the mutual solubilities of three C6hydrocarbons (benzene, cyclohexane,n‐hexane) and water were experimentally investigated and, together with critically selected literature data, were correlated up to the three‐phase critical end point. The present paper extends this analysis to the mutual solubilities of three C8hydrocarbons (ethylbenzene, ethylcyclohexane,n‐octane) and water, which have been measured at the three‐phase equilibrium pressure up to the critical temperatures (568, 561 and 539 K, respectively). A thermodynamic analysis of these new measurements and of available literature data has been performed up to the three‐phase critical end point. Information is also provided on vapor‐phase equilibrium compositions. The solubility of hydrocarbons in water has been used to calculate Henry's constants, while the solubility and volatility of water in hydrocarbons has been successfully correlated with several modifications of the Redlich‐Kwong equa

ISSN:0001-1541    

DOI:10.1002/aic.690310304

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractA numerical simulation of a pressure swing adsorption process is presented for a system in which a small concentration of an adsorbable component is separated from an inert carrier. Linear equilibrium and a linear rate expression are assumed. The model equations were solved by orthogonal collocation and by finite difference methods with consistent results. The theory is shown to provide a good representation of the experimental data of Mitchell and Shendalman (1973) for the system CO2‐He‐silica

ISSN:0001-1541    

DOI:10.1002/aic.690310305

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractA new method of representation of electrolyte solution nonideality is derived, on the basis of similar assumptions, from a model applied by Cruz and Renon (1978) to binary electrolyte solutions. In order to test the validity of the model for representation of strong electrolyte properties, parameters were fitted to osmotic coefficient data for single, completely dissociated salts in aqueous solutions and were used to calculate osmotic coefficients of mixed aqueous electrolytes. Results are compared with those given by Chen's local composition model (Chen et al., 1982; Aspen, 1983) and Pitzer's truncated model (Pitzer, 1973, 1979; Pitzer and Mayorga, 1973; Pitzer and Kim, 1974), the same number of adjustable parameters being used in each case.The average standard deviations for single electrolytes are within 1% in the case of 1–1 salts for the three models, and within 2% in the other cases, except for Chen's model (5%). As for predicted results, both local‐composition models yield standard deviations of less than 2%, while the accuracy given by the Pitzer model is better than 1

ISSN:0001-1541    

DOI:10.1002/aic.690310306

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractEffluent concentration profiles from high performance displacement chromatography were calculated by using the theory of equilibrium chromatography of Helfferich and Klein (1970). The close agreement between predictions of the theory neglecting mass transfer resistances and experimental results demonstrates that conditions close to ideal chromatography are attainable in HPLC. Individual adsorption isotherms, as measured by frontal development, closely followed Langmuirian behavior.

ISSN:0001-1541    

DOI:10.1002/aic.690310307

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractHeat treatment of “shell” molybdena‐alumina catalyst pellets results in macroscopic redistribution of the molybdena. Redistribution is minimal at 625°C but extensive at 750°C. After 6 hours at 750°, a sharp maximum is observed in the radial distribution. This is a result of opposing factors: radial diffusion inward from the initial shell, and preferential sintering of the alumina support in the shell region. Loss of molybdena by vaporization is not appreciable at 750°C but is serious at 875°C. A computer program has been developed to convert SEM‐EDAX (scanning electron microscopy energy‐dispersive analysis of x‐ray) data for unpolished pellet section to a quantitative, smooth profile of Mo concentration as a function of reduced

ISSN:0001-1541    

DOI:10.1002/aic.690310308

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractPrevious papers (Trogus et al., 1979a; Harwell et al., 1982) have developed a theory of surfactant chromatographic movement on the assumption that micelles may be treated as a separate thermodynamic phase in predicting surfactant adsorption. The work examined here demonstrates that, even with incorporation of the complex surface interactions between surfactant molecules that are present in real systems, conclusions and observations made in the previous studies hold true. Additionally, theoretical predictions are compared to experimental results to demonstrate that for the system studied the phase separation model of micelle formation (Shinoda, 1963) and the plateau adsorption model (Trogus et al., 1979a) are powerful and useful simplifications for predicting surfactant chromatographic behavior.

ISSN:0001-1541    

DOI:10.1002/aic.690310309

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractA strategy for synthesizing regulatory control structures is developed within the framework provided by singular value decomposition (SVD). Quantitative measures of interaction and sensitivity for the nodes, as well as for the entire system, are established with this method. The approach enables analysis of the control struture over a range of frequencies which are of practical importance for a particular processing unit, thus insuring that both static and dynamic effects are encompassed. In addition, this method allows the designer to identify the modeling aspects which are important in determining the performance of the synthesized control structures. A series of examples, presented in order of increasing complexity, demonstrate the usefulness and versatility of this procedure. The technique is implemented as an interactive computer package.

ISSN:0001-1541    

DOI:10.1002/aic.690310310

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY

摘要:

AbstractCoiling of a tube produces a profound change in the internal flow patterns due to the generation of a centrifugally driven secondary flow. This change strongly influences the transport processes in a coiled tube. The present paper investigates the influence of such secondary flow on a process of convective diffusion with reaction. The findings have an important bearing on a better understanding of a coiled tube reactor.

ISSN:0001-1541    

DOI:10.1002/aic.690310311

出版商:American Institute of Chemical Engineers    

年代:1985

数据来源: WILEY