摘要:

AbstractA major, national program to exploit geothermal energy requires creative chemical engineering solutions to a wide array of difficult problems. With some overlap, most of the problems fall into these categories: resource development and management, energy extraction and utilization, power cycle design and optimization, environmental engineering, and corrosion and scaling of equipment. Reinjection of waste fluids, insofar as it proves feasible, will affect the shape of the solutions in all categories.Convective hydrothermal reservoirs, the most accessible and well characterized of geothermal resources, are immense, permeable media in which heat and mass transport are coupled with chemical reaction. Despite decades of effort, no satisfactory physical or mathematical model exists for any reservoir. Even less is known about the hot rock and geopressured resources, which also may be utilized ultimately.Electric power production receives primary emphasis in the United States, both in terms of current utilization and of research and development. Worldwide, however, the total power devoted to agricultural activities, space heating and cooling, and process heat applications is greater than that to electric power conversion.Because hydrothermal reservoirs are low temperature (<350°C) sources of corrosive fluids, much current development effort aims at power cycles that promise enhanced efficiencies and that avoid some of the problems of corrosion and scaling. Among the candidates are several binary cycles which employ secondary working fluids, and the total flow concept, which utilizes two‐phase flow from the production wells.Once thought to be all but negligible, the environmental effects of geothermal installations have recently been subjected to informed scrutiny and found nonnegligible. Among the problem areas are gaseous effluents including hydrogen sulfide, mercury, radon, ammonia, and H3BO3and aqueous emissions that contain heavy metals. Reinjection of waste geothermal fluids would ameliorate many environmental impacts but could be complicated by silica deposition in equipment and in the underground reservo

ISSN:0001-1541    

DOI:10.1002/aic.690220502

出版商:American Institute of Chemical Engineers    

年代:1976

数据来源: WILEY

摘要:

AbstractThe sorption and rate of permeation of scopolamine base in human skin have been measured as a function of drug concentration in aqueous solution contacting the stratum corneum surface of the skin. The sorption isotherm is nonlinear, and the apparent penetrant diffusivity computed from steady state permeation data is greater than that estimated from unsteady state (time lag) measurements.By assuming that sorption occurs by both ordinary dissolution and binding of penetrant to immobile sites in the membrane, the experimental sorption isotherm can be predicted, and the disparity between steady state and time lag diffusivities can be reconciled.

ISSN:0001-1541    

DOI:10.1002/aic.690220503

出版商:American Institute of Chemical Engineers    

年代:1976

数据来源: WILEY

摘要:

AbstractShear viscosity of an Amioca starch paste undergoing hydrolysis by immobilized α‐amylase is shown to follow a power law behavior. The power law constants are uniquely related in a way which reduces the power law to a dimensionless form, a result previously reported only for retrograding starch and coagulating milk. The concept of a total hydrodynamic volume [Amioca starch molecules (amylopectin) plus associated immobilized liquid] is extended to concentrations above the dilute solution regime. A molecular interpretation is proposed for the shear viscosity behavior of Amioca starch pastes vs. extent of starch hydrolys

ISSN:0001-1541    

DOI:10.1002/aic.690220504

出版商:American Institute of Chemical Engineers    

年代:1976

数据来源: WILEY

摘要:

AbstractThe dynamic behavior of aerosol size distributions under the influence of coagulation and growth by heterogeneous condensation of gaseous species is studied. Analytical solutions are obtained to the integro‐differential equation governing the aerosol size distribution density function. Two modes of coagulation (constant and linear coagulation constants) and two modes of condensation (growth independent of particle volume and linearly dependent on particle volume) are considered. The interaction of the two growth mechanisms on aerosol size distributions is elucidate

ISSN:0001-1541    

DOI:10.1002/aic.690220505

出版商:American Institute of Chemical Engineers    

年代:1976

数据来源: WILEY

摘要:

AbstractBench scale packed columns were used to study the kinetic behavior of biological denitrification. After tracer studies were run to determine flow characteristics, steady state nitrate profiles were determined. A first‐order rate expression with an Arrhenius temperature dependence is an adequate model of the reaction for nitrate‐nitrogen concentrations of<100 mg/l and temperature of 5° to 20°C. The rate constants are proportional to the packing surface

ISSN:0001-1541    

DOI:10.1002/aic.690220506

出版商:American Institute of Chemical Engineers    

年代:1976

数据来源: WILEY

摘要:

AbstractThe stability of various chemical engineering systems is studied through the use of vector Lyapunov functions. A decomposition technique is employed which reduces the problem to small, independent, free subsystems that can be analyzed through Lyapunov's second method. The stability characteristics of the overall system are then related to the behavior of a linear system which is easily analyzed.

ISSN:0001-1541    

DOI:10.1002/aic.690220507

出版商:American Institute of Chemical Engineers    

年代:1976

数据来源: WILEY

摘要:

AbstractExperimental data on the frequency and wavelength of finite amplitude equilibrium waves on the surface of nonvertical laminar falling films of mineral oil at moderate Reynolds numbers are correlated successfully on the basis that the frequency of the wave remains constant during the course of its amplification.

ISSN:0001-1541    

DOI:10.1002/aic.690220508

出版商:American Institute of Chemical Engineers    

年代:1976

数据来源: WILEY

摘要:

AbstractThe system of a dispersed phase oscillating in a continuous medium is investigated theoretically with the specific purpose of developing a new technique for the measurement of interfacial viscous and elastic properties. By use of the well‐known models of interfacial mechanics, the decay and frequency of liquid drops oscillating in a gas and of gas cavities oscillating in a liquid are computed as functions of dynamic interfacial properties. The results of the theory indicate, for the size range considered, that the elastic properties dominate over the viscous properties and that dilational effects dominate in the case of the drop in air and shear effects dominate in the case of the cavity in a liquid. The frequency does not seem to depend on the dynamic interfacial propertie

ISSN:0001-1541    

DOI:10.1002/aic.690220509

出版商:American Institute of Chemical Engineers    

年代:1976

数据来源: WILEY

摘要:

AbstractUltra high‐speed motion picture photography is used to measure the decay and frequency of drops of liquid in air and of air cavities in liquids. Consequent to the belief that surface active agents induce dynamic interfacial properties, a very clean system is used, and experiments are performed with triple distilled water, tap water, and known aqueous solutions of ionic and nonionic surfactants. Experimental results yield good qualitative agreement with the theory. The theoretical and experimental studies show the system to be a new and promising technique for the quantitative evaluation of the various interfacial viscous and elastic propertie

ISSN:0001-1541    

DOI:10.1002/aic.690220510

出版商:American Institute of Chemical Engineers    

年代:1976

数据来源: WILEY

摘要:

AbstractThe kinetics of sorption of four representative hydrocarbons in 13X zeolite crystals have been investigated at temperatures within the range 409 to 513°K and pressures 0.1 to 100 torr. Extensive diffusivity data are presented showing the dependence on sorbate concentration and temperature. The form of the concentration dependence of the diffusivity for these systems is very similar to that of the small monatomic and diatomic molecules in 5A zeolite. This similarity is understandable, since the key factor which determines the diffusion behavior is the relative size of diffusing molecule and sieve window. For these hydrocarbons in the 13X sieve, as for the monatomic and diatomic gases in 5A, the critical diameters of the diffusing molecules are all appreciably smaller than the free diameter of the windows

ISSN:0001-1541    

DOI:10.1002/aic.690220511

出版商:American Institute of Chemical Engineers    

年代:1976

数据来源: WILEY