Optimisation of the dryer and back coating processes for carpet manufacturing in terms of heater configuration, nozzle shape, airflow and control / adjustment
Energy costs for ventilation and heating account for the largest part in running costs in carpet manufacturing, so that, reducing them leads to a considerable decrease of production costs. The project aimed at the optimisation of the drying process, including the improvement of the burners and air flow conditions. The air flow was therefore measured on the material surface to obtain this improvement. Results are to serve the optimisation of existing plants as well as the development of new dryer designs. The profits of the project concerns the reduction of energy costs, the reduction of material-related plant emissions and the improvement of product quality. In the beginning of the project detailed measurements for status determination in carpet production lines where made. At the same time a lab-scale dryer for research activities was installed. Afterwards the different parts of the dryer were optimised at the test rig and tested industrially. In a concluding task the results of the optimisation were evaluated. The results of air flow and temperature measurements at industry dryers made clear that there is a high potential of optimisation. The industrial air-flow optimisation was focused on the optimised setting of the exhaust gas flap valves at the different sections of the dryer and showed a significant energy saving. The newly developed nozzle box design shows a low pressure drop, an even velocity at the nozzle outlet between entrance and the end of the nozzle box as well as an airflow which is perpendicular to the carpet. For the industrial optimisation of existing nozzle boxes a guiding sheet kit which can be installed in a simple way has been developed. The research activities on the optimisation of the burner results in a significant reduction of carbon monoxide and methane, realized by the installation and the optimised adjustment of a passive pre-mixing (air & gas) system. This system is based on the venturi principle. The evaluation showed that the total thermal energy reduction amounts at least 15% by using the developed features of air flow and nozzle box optimisation at existing dryers.