Flour cooling system

One of the most important will of the industrial bakery company is to make the better product possible and to have it constant in time. To make it possible two are the main factors: the production cycle and the total ingredient’s conditions at the beginning of the process have to be the same. The first point is easily achievable nowadays in companies through the automation of the production process, leading to a fully automatic and controlled production cycle. However, the second point relates to the temperature of the dough and primarily to the temperatures of the two main ingredients used in larger quantities: flour and water. In particular, before mixing all the ingredients, the overall temperature of the mixture should be around 15°C. This becomes challenging to achieve, especially during the summer months, because the flour, stored in silos outside the facility, reaches temperatures of around 35-40°C. To overcome this problem, ice is often used instead of water. However, using ice has some drawbacks as it slows down the mixing time, it does not contribute to proper dough development, it requires the purchase of specific machinery, and it adds high energy consumption costs. This study aimed at developing a flour cooling system in the way to cool down the flour especially in summer when it reach a temperature about 40°C. Firstly, a customized and continuous solution has been studied for a special client of the company to understand the potential of the chosen cooling principle and calculate the efficiency of the system. Specifically, cold and dry air has been used to cool down the flour through convection and adiabatic cooling, absorbing moisture from the flour, which contains about 15% water by weight. To meet high production capacities, tests have been conducted with smaller quantities of flour, and subsequently, the LMTD and ε-NTU methods have been used to estimate the required airflow to achieve the desired final temperature as requested by the client. Secondly, two standardized solutions of smaller dimensions have been studied, which were non-continuous in order to process only the required amount of flour and provide a flexible system. For the first non-continuous system, the same operating principle analyzed earlier has been employed, focusing on the system's performance and limitations during the tests. On the other hand, the second non-continuous system has been divided into two separate cooling stages: transport and cooling in the dosing hopper. Tests were conducted to study both the cooling processes in order to construct curves that allow to calculate the required process times and achieve a constant temperature of the flour throughout the lifespan of the plant. In this system, cold and dry air, similar to the previously studied systems, has been used, but some modifications have been made to address the main issues encountered and improve the overall performance.