Simulation of fermentor cooling performance

Abstract

A major heat transfer process occurring in a brewery operation takes place in a brewhouse fermentor tank. Heat transfer requirements in the fermentor process include attemperating fermenting wort and then cooling end-fermented beer in the tank to a temperature near freezing. Proper design of the fermentor cooling system is necessary to meet process temperature specifications, and it can have a significant impact on both the capital and operating costs of the vessel. This report describes an experimental and analytical heat transfer study of the cooling phase of the fermentor tank process. The fermentor tank cooling performance was studied with a combination of theoretical analyses and temperature measuring experiments in both full-size tanks in breweries and scaled-down laboratory vessels. The theory consisted of an analysis of the cooling characteristics of fermentors, and an analytical model which can be used to compare the cooling performane of full-scale and laoratory size fermentor. The result of the theory is a simulation thechnique which uses experimental heat transfer data obtained in a laboratory model to predict the cooling operation of a full-scale fermentor. The plant and laboratory experiments included axial and radial tempertaure measurements as a funktion of time during the cooling processes. The temperature measurements were then used to calculate the bulk temperature-time history of the beer in both the full-scale and laboratory vessels. Analysis of the bulk tempertaure-time history showed that the fermentor cooling performance could be correlated by the theory and that the developed simulation technique is a useful engineering approach in the design and prediction of a brewhouse fermentor cooling system.