Evaluation of eggshell drying on a laboratory scale for industrial use

Abstract

The Cuban industry La Purísima produces sauces and dressings for the
national gastronomy; but it does not have a process for the deposition of
chicken eggshells, as a result, 220 kg of eggshells are dumped daily, which
generate a negative impact on the environment. The research evaluates the
drying of hen eggshells with protein membrane on a laboratory scale, with a
view to revalorizing this waste in the production of a calcium-rich poultry feed
supplement. The calcium carbonate content of the shell was determined to
confirm the potential application of the residue. The drying curve and drying rate
curve was obtained by experimental measurement in a drying oven under
aeration at 90 °C. The calcium carbonate content of the residue was 93.33 %.
The drying curve was fitted to an exponential mathematical model as a function
of the drying constant and the moisture in equilibrium at a temperature of 90 °C.
The drying regime of the solid presented a period of decreasing drying rate up
to a moisture value of 0,021 kg of water / kg of dry solid, for lower values, this
presented a deviation from the exponential function in its rate. The utilization of
residual eggshells proved to be an attractive source of calcium carbonate with
potential for its use in the production of feed supplement for poultry.