A computer based solution to check the drop in milk outlet temperature due to fouling in a tubular heat exchanger

Milk fouling is the main cause of progressive decline in the rate of heat transfer in a UHT milk sterilizer, which results in a drop in milk outlet temperature as the processing advances. Increasing steam temperature is one of the ways to overcome the drop in milk outlet temperature and prolong the operating time before the processing is stopped for cleaning of deposits in the heat exchanger. A computer model is developed for accurate control of milk temperature as affected by fouling. It can calculate accurately the increase in steam temperature required for maintaining the desired milk sterilization temperature. The results with steam control are compared with the results without any control and this procedure was found satisfactory for controlling the milk outlet temperature. The procedure described can be applied to any heat exchanger with minor modifications, if necessary.

[1]  A. Datta,et al.  Milk fouling simulation in a double tube heat exchanger , 2003 .

[2]  Michael C. Georgiadis,et al.  Optimal design and operation of heat exchangers under milk fouling , 1998 .

[3]  R. Marshall.  Effects of iodate, hydrogen peroxide and dichromate on the denaturation of whey proteins in heated milk , 1986, Journal of Dairy Research.

[4]  Michael C. Georgiadis,et al.  Modeling and simulation of shell and tube heat exchangers under milk fouling , 1998 .

[5]  R. Lyster.  The composition of milk deposits in an ultra-high-temperature plant , 1965, Journal of Dairy Research.

[6]  Jan De Block,et al.  Applications of modelling to optimise ultra high temperature milk heat exchangers with respect to fouling , 2004 .

[7]  P. De Jong,et al.  Modelling and optimization of thermal processes in the dairy industry , 1996 .

[8]  T. R. Bott.  Fouling of Heat Exchangers , 1995 .

[9]  P. Skudder,et al.  Aseptic processing of food products using ohmic heating , 1987 .

[10]  K. Swartzel.  Tubular Heat Exchanger Fouling by Milk During Ultra High Temperature Processing , 1983 .

[11]  P. Skudder,et al.  Effects of adding potassium iodate to milk before UHT treatment: I. Reduction in the amount of deposit on the heated surfaces , 1981, Journal of Dairy Research.

[12]  P. Fryer,et al.  A Comparison of Milk and Whey Fouling in a Pilot Scale Plate Heat Exchanger: Implications for Modelling and Mechanistic Studies , 1999 .

[13]  Deposition of Milk Solids on Heated Surfaces , 1968 .

[14]  Peter de Jong,et al.  Reduction of fouling and contamination by predictive kinetic models , 2002 .

[15]  Deposit formation in UHT plants. I. Effect of forewarming in indirectly heated plants , 1986 .

[16]  R. Benning,et al.  Hybrid model of the fouling process in tubular heat exchangers for the dairy industry , 2002 .

[17]  William R. Paterson,et al.  The effect of Reynolds number and fluid temperature in whey protein fouling , 1993 .

[18]  T. Jeurnink.  Fouling of heat exchangers by fresh and reconstituted milk and the influence of air bubbles , 1995 .

[19]  T. Jeurnink,et al.  Fouling of heat exchangers in the dairy industry , 1997 .

[20]  P. K. Sahoo,et al.  A computer based iterative solution for accurate estimation of heat transfer coefficients in a helical tube heat exchanger , 2003 .

[21]  J. Mottar,et al.  Optimization of the forewarming process with respect to deposit formation in indirect ultra high temperature plants and the quality of milk , 1988, Journal of Dairy Research.

[22]  H. Burton.  A comparison between a hot-wire laboratory apparatus and a plate heat exchanger for determining the sensitivity of milk to deposit formation , 1966 .

[23]  Georges Corrieu,et al.  Fouling of a plate heat exchanger used in ultra-high-temperature sterilization of milk , 1984, Journal of Dairy Research.

[24]  Andreas Acrivos,et al.  Method of Characteristics Technique. Application to Heat and Mass Transfer Problems , 1956 .

[25]  S. G. Roscoe,et al.  Fouling of model surfaces : adsorption and removal of whole unpasteurized milk , 1994 .

[26]  Computer-aided design and performance evaluation of an indirect type helical tube ultra-high temperature (UHT) milk sterilizer , 2002 .

[27]  C. F. Sanders,et al.  Prevention of Milestone Formation in a High-Temperature-Short-Time Heater by Preheating Milk, Skim Milk and Whey , 1944 .

[28]  P. Skudder,et al.  Effect of pH on the formation of deposit from milk on heated surfaces during ultra high temperature processing , 1986, Journal of Dairy Research.

[29]  M. Burdett.  The effect of phosphates in lowering the amount of deposit formation during the heat treatment of milk , 1974, Journal of Dairy Research.

[30]  Peter J. Fryer,et al.  The simulation of heat exchanger control with tube-side chemical reaction fouling , 1986 .

[31]  R. K. Singh,et al.  Energy increases in operation and cleaning due to heat-exchanger fouling in milk pasteurization , 1991 .

[32]  Peter J. Fryer,et al.  Fouling and Cleaning in Food Processing , 1999 .

[33]  Peter J. Fryer,et al.  The uses of fouling models in the design of food process plant , 2007 .

[34]  Peter J. Fryer,et al.  A direct simulation procedure for chemical reaction fouling in heat exchangers , 1985 .

[35]  Peter J. Fryer,et al.  Shape and conductivity effects in the ohmic heating of foods , 1989 .

[36]  T. Jeurnink,et al.  Deposition of heated whey proteins on a chromium oxide surface. , 1996 .

[37]  C. L. Foster,et al.  A model heat-exchange apparatus for the investigation of fouling of stainless steel surfaces by milk I. Deposit formation at 100 °C , 1989, Journal of Dairy Research.

[38]  H. Burton,et al.  Section G. Deposits from whole milk in heat treatment plant—a review and discussion , 1968, Journal of Dairy Research.

[39]  C. L. Foster,et al.  A model heat exchange apparatus for the investigation of fouling of stainless steel surfaces by milk II. Deposition of fouling material at 140 °C, its adhesion and depth profiling , 1990, Journal of Dairy Research.

[40]  H. Burton,et al.  Effect of free fatty acids on the amount of deposit formed from milk on heated surfaces , 1979, Journal of Dairy Research.