SPINNING DISC MEASUREMENT OF TWO-STAGE CLEANING OF HEAT TRANSFER FOULING DEPOSITS OF MILK
The efficient and effective cleaning of milk protein – based deposits from heat transfer equipment is essential in the dairy industry. The aim of this study was to evaluate the effectiveness of two-stage cleaning using acid and caustic. Stainless steel discs were fouled during heat transfer by skimmed milk and whey protein. The discs were then cleaned with acid and sodium hydroxide solutions under controlled mass transfer conditions using spinning disc techniques. The use of 0.5% nitric acid, and a commercial acid known as Triplex, as a rinse before caustic cleaning increased the cleaning rate by 2.5 times. The foulant was found to swell about 40% and calcium was leached out within 5 min after exposure to acid. The acid treatment is believed to cause a reduction in the viscosity, and hence an increase in dissolution, of the gel layer formed when caustic cleaning takes place.
Document Type: Research Article
Affiliations: 1: Department of Chemical and Process Engineering University of Canterbury Private Bag 4800 Christchurch, New Zealand 2: Department of Chemical Engineering Odense University College of Engineering Odense, Denmark
Publication date: 2005-12-01