Validação de parâmetros de volumes de Priming e Flushing entre tanques durante resfriamento de iogurte

Abstract

The production of yogurt is based on the lactic fermentation of sugars present in the preparation blend. The fermentative activity is interrupted by cooling the yogurt. Industrially, the fermentation process occurs in one tank, and then an already cooled mass is storaged in another tank. Between these tanks occurs the passage of the product through a heat exchanger, for cooling the yogurt. Mass transport between the tanks is promoted by positive pumps for the most part, but the initial and final phases of each fermentation tank are in direct contact with the water phases. At first, the pipes are filled with waste water, so the first phase to leave the fermentation tank, towards the heat exchanger is responsible for moving the waste water phase. This initial impulse is called "Priming." At the end of the fermentation tank volume, a sterile water supply valve is opened to promote the movement of the final fermented mass. This final thrust is called "Flushing." The residual water present between the intermediate phases must not enter the final storage tanks, as this directly compromises the quality of the product. To this end, the inlet valve of the storage tank is programmed to open and close in order to divert the residual water phase to the drain. This valve control is based on volume parameters that measure an amount of each phase that has already passed each point of the line. The objective of this work is to draw a mathematical model that measures the exact volume of each phase, and the ideal opening time of the storage tank valve, according to the length and the diameter of the pipe to be covered by the mass, flow rate, loss of charge and influence of the viscosity of the product.