Design of a batch tray dryer for the valorization of residual eggshells

Abstract

The industrial process for the production of mayonnaise is associated with the disposal of eggshells as solid waste. The sauces and dressings factory "Los atrevidos" is interested in valorizing this waste by incorporating a technological system capable of treating its waste and minimizing its environmental impact through process intensification and cleaner production. The present research aims to design a technological-productive system for the treatment of residual eggshells to obtain animal feed supplement rich in calcium carbonate, with emphasis on the design of a batch tray dryer. Material balances were developed to quantify the waste load to be treated, the necessary inputs and the projection of the technological production scheme. The production plant was designed to handle up to 500 kg/day of eggshells; the main production stages are: treatment of raw materials, drying, milling and sieving, with the batch drying stage receiving the most attention. The batch dryer designed had 7 trays of 1.5 m2 area and 1.75 m high. The hot air flow at 90 °C is 1,578 kg/h and the work regime is by 4-hour batches (up to 6 batches per day). The proposed production scheme does not generate waste to be treated, and responds to an environmental problem in the mayonnaise and dressing industry, making it a more environmentally friendly industrial process.