Effect of colloidal Particles associated with the liquid bridge in sticking during drying in Superheated Steam


National Centre for Engineering in Agriculture, USQ


It is very important in the design of a drying system is to evaluate sticking behaviour of the materials goes under drying. A new approach to the sticking issue is applied in this study by carrying out a sticking test for the liquid associated with the materials under study. It was found that the liquid bridge is responsible of the initial sticking of the materials to the contact surface and the colloidal material in this liquid is eventually responsible of building a sticky solid bridge during drying. The glass transition temperature for the Brewers Spent Grain (BSG) particles and the colloidal solution that expelled from these particles is tested using Differential Scanning Calorimetric (DSC). However that the chopped BSG particles showed no glass transition temperature there was a marked amount of it that sticked to the rotary drum dryer and the sample holders during drying. The sticking behaviour may be regarded to the colloidal particles in the liquid associated with the grain. The colloidal particles in this liquid is filtered and concentrated through evaporation and then tested by the (DSC) where it showed a glass transition temperature at (-23) and (-33) C. In addition, the associated liquid has a honey shape and a sticky touch when concentrated. These two properties are an indication that this colloidal material may be responsible of sticking the BSG to the steel surfaces during drying.