Turbulence Analysis of Pulp Drying Process in Cylindrical Dryer Using Mass and Heat Transfer Method

Sri Wuryanti

Abstract: The drying process is an essential step in paper making. The process generally consists of two stages: pre-drying and after-drying using drying process technology. This drying process requires a certain amount of energy, namely heat from steam. The analytical method uses a heat and mass transfer model approach. The heat transfer and mass transfer models can determine the amount of water content reduction in the cylinder dryer. Turbulence analysis in the drying process aims to see whether there is a relationship between turbulence with mass transfer rate and heat transfer rate. The analysis results show that wet paper's turbulence is proportional to the mass and heat transfer rates. The highest and lowest heat transfer results in the pre-dryer are 5.28 x 10-7 kg mol/m2 and 4.8 x 10 -7 kg mol/m2 s, while in the after-dryer; it is 6.5 x 10-8 kg moles /m2 s and 5.8 x 10-8 kg mol/m2 s. The highest and lowest turbulence values in the Pre-dryer are 9200 and 8131, respectively, while in the After-dryer are 6144 and 5426.

Keywords: dryer, energy, paper, cylinder, steam