Determination and modelling of drying characteristic in industrial type dryer

In the textile industry, hot air spray drying is one of the quite often used and too much energy consuming methods. Because of today's increasing energy demand, it has become a necessity to optimize existing energy systems and to manufacture new designs more efficiently. With the help of mathematical models that determine the performance of energy systems, energy consumption can be greatly reduced. The most widely used convection drying machines in the textile industry are Ram machines, which are called Ramos, in order not to damage the structure while the textile products are dried and to adjust the desired width / length. Ram machines are cloth-drying machines in which fabrics are moved horizontally in the machine and in the meantime hot air spraying to the fabric. When the drying characteristic is examined in the Ram machines, the drying efficiency can be increased in large scale by means of the models, which allow optimization of drying conditions. In this study, the drying characteristic of a 10-cabinet ram machine was experimentally investigated and the drying behavior was modeled through two different theoretical models. The experiments were carried out under real production conditions using three different drying air temperatures (110-130-150 oC) and three different fabric feed speed (0.167-0.333-0.500 m/s) and 95% cotton + 5% lycra content fabric. Using the data obtained from the experiments, the heat-mass transfer coefficient, evaporation rate, humidity ratio, drying speed values were calculated for each cabinet of the dryer. In the modeling of the drying characteristic, first order kinetic model and diffusion model, which two different theoretical models derived from Fick's second law, were used and comparison was made between these models. First order kinetic coefficients, effective diffusion coefficients and activation energy values were calculated for each drying condition with the help of the used models. As a result, the drying characteristic of a 10 cabinet Ram machine was investigated with two different theoretical models under actual production conditions. The conformity of between the models and the experimental data were compared using regression analysis. For the first order kinetic model, it was observed that the R2 value varied between 0.9945 and 0.9992, χ2 value varied between 0.00005 and 0.00122, RMSE value varied between 0.0045 and 0.0129, and r-value varied between 0.9973 and 0.9998. For the diffusion model, it was observed that the R2 value varied between 0.9812 and 0.9961, χ2 value varied between 0.00109 and 0.00646, RMSE value varied between 0.0109 and 0.0289, and r-value varied between 0.9905 and 0.9980. According to these values, it was concluded that the use of first order kinetic model is more appropriate than the diffusion model as a drying modeling tool in the ram machine.