Optimization of energy usage in the hydroentanglement process

Abstract

The hydroentanglement process is highly energy intensive compared to other methods of manufacturing nonwoven fabrics. This paper presents an exploratory study on optimizing the usage of hydroentanglement energy so as to lower the processing cost. The experiments were based on a Box–Behnken experimental design (BBD) and multivariate linear regression analysis to model the tensile strength as response to variables. Three variables were selected, namely fabric area weight (150–400 g/m2), machine speed (5–15 m/min) and waterjet pressure (40–200 bars). These parameters were employed in two sets of experiments to achieve maximum tensile strength of viscose nonwoven fabrics. The first experiment was conducted using higher waterjet pressures of 100, 150 and 200 bars, which were proved to have exceeded the optimum levels. The second experiment was conducted at relatively lower waterjet pressures of 40, 60 and 80 bars. The results on tensile strength were analyzed using the SYSTAT 10 software package and response surface plots were prepared. The linear, quadratic and interactive effects of the main variables were shown to be significant. Interactions amongst the variables were found to have either a synergistic (positive) or offsetting (negative) relationship with the fabric tensile strength. The interactions involving machine speed were predominantly offsetting. The 400 g/m2 area weight fabric produced at 80 bars of waterjet pressure achieved a fabric tensile strength of 222 cN, which compared favorably with that of 232 cN obtained at 200 bars of waterjet pressure. In this exploratory study using BBD, linear, quadratic and interactive effects were observed to be significant and the usage of hydroentanglement energy was successfully optimized. This indicates the possibility of achieving high fabric strength but at lower waterjet pressures; in other words, by employing low hydroentanglement energy and thereby minimizing the processing cost.