3 research outputs found
Perturbation solution of hollow-fiber membrane module for pure gas permeation
No full textThis study presents an analytic solution for permeation of a pure gas in a hollow-fiber module, based on regular perturbation method. It is assumed that pressure drop due to frictional loss should be proportional to velocity, and that mass transfer be mainly convective with the permeation through the fiber membrane. Four governing equations are characterized by five parameters depending on the design specifications and operating conditions of the module. When the parameter characterizing pressure drop is small, regular perturbation method is capable of providing the analytic solution. Compared with numerical simulation, the analytic solution is found to be sufficiently precise when the parameter is far less than the other parameters characterizing the mass transfer and pressure difference between permeate and reject streams. (C) 1998 Elsevier Science B.V
Effect of pressure drop on performance of hollow-fiber membrane module for gas permeation
No full textThe pressure drop mainly due to viscous friction inside hollow fibers is taken into consideration by nondimensionalization and numerical simulation of governing equations. For pure gas, the permeation pressure and velocity of actual situations with a viscous fluid deviate significantly from those of the corresponding inviscid or no-pressure-drop cases. The apparent permeability estimated from the relation of permeate now rate and pressure difference is considerably underestimated in actual situations, and more severely for the region of small pressure difference and large module length. Numerical simulation shows that the estimated permeability behaves as if it were an increasing function of pressure difference for a constant permeability and roughly a constant for a dual-sorption-type permeability, respectively. For binary-mixture permeation the cut ratio and purity of permeate stream are mainly governed by two dimensionless parameters standing for pressure drop and permeability, respectively. The cut ratio and corresponding product composition are predictable without the rigorous simulation of the governing equations
NIR Calibrations for Soybean Seeds and Soy Food Composition Analysis: Total Carbohydrates, Oil, Proteins and Water Contents
No full textConventional chemical analysis techniques are expensive, time consuming, and often destructive. The non-invasive Near Infrared (NIR) technology was introduced over the last decades for wide-scale, inexpensive chemical analysis of food and crop seed composition (see Williams and Norris, 1987; Wilcox and Cavins, 1995; Buning and Diller, 2000 for reviews of the NIR technique development stage prior to 1998, when Diode Arrays were introduced to NIR). NIR spectroscopic measurements obey Lambert and Beer’s law, and quantitative measurements can be successfully made with high speed and ease of operation. NIR has been used in a great variety of food applications. General applications of products analyzed come from all sectors of the food industry including meats, grains, and dairy products (Shadow, 1998)
