Estimation of the effective diffusion coefficient of water in skim milk during single-drop drying

被引：0

作者：

Malafronte, L. ^{[1
,2
]}

Ahrné, L. ^{[1
]}

Kaunisto, E. ^{[1
]}

Innings, F. ^{[3
]}

Rasmuson, A. ^{[2
]}

机构：

[1] Process and Technology Development, SIK - The Swedish Institute for Food and Biotechnology, Gothenburg, Sweden

[2] Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden

[3] Research and Technology, Tetra Pak Processing Systems, Lund, Sweden

来源：

Journal of Food Engineering | 2015年 / 147卷 / 0C期

关键词：

Diffusion - Drops - Nuclear magnetic resonance - Spray drying - Temperature distribution;

D O I：

暂无

中图分类号：

TK1 [热力工程、热机];

学科分类号：

080702 ;

摘要：

This paper presents a new approach combining experimental methodology and modelling, developed to evaluate the effective diffusivity of water in skim milk during drying over a full range of water contents and temperatures. This parameter is important to support modelling of spray-drying processes and designing of equipment. The effective diffusion coefficient is evaluated using a combination of nuclear magnetic resonance (NMR) and parameter estimation. NMR is used to determine the temperature dependence and parameter estimation is used to estimate the water concentration dependence of the effective diffusivity of water in skim milk (0.90 on total weight basis) during drying by comparing the experimental data obtained using a suspended-drop method, which allows the recording of weight and temperature changes during drying, with the results of a distributed heat and mass transport model. The results indicate that the free-volume theory best predicts the dependence of the effective diffusion coefficient of water in skim milk. A mathematical correlation of effective diffusivity over a full range of water contents and temperatures (from 50 to 90 °C) was obtained and experimentally successfully validated for concentrated skim milk (0.70 on total weight basis). © 2014 Elsevier Ltd. All rights reserved.

引用

页码：111 / 119