In this paper, the influence of low power factor on electricity system and the influence of paper breaking on heat system are presented. For that, a mathematical model and a case study for a paper mill are realised. T...In this paper, the influence of low power factor on electricity system and the influence of paper breaking on heat system are presented. For that, a mathematical model and a case study for a paper mill are realised. The electric mathematical model is based on the relations of energy losses in cables and in transformers as a function of power factor. The thermal mathematical model includes characteristic energy and efficiency of boiler depending on its load. Characteristic of efficiency is modeled by a quadratic dependence between fuel consumption and steam flow. In the case, study were estimated to reduce energy losses for factor neutral （0.92） against real power factor （0.75） for the electrical scheme of a paper machine. Analytical expression of the boiler characteristic and variation of boiler efficiency depending on its load were estimated, too.展开更多
By dividing the rewinding process of a three-roll rewinder into three zones, mathematical equations were formulated and diagrams were drawn to determine the structure factors of the rewinder, such as the diameters and...By dividing the rewinding process of a three-roll rewinder into three zones, mathematical equations were formulated and diagrams were drawn to determine the structure factors of the rewinder, such as the diameters and spatial distribution of the rewinding rolls. The qualitative and quantitative analysis results show that the roll gap of the first two rewinding rolls and the angle between the line that connects the center points of the first two rewinding rolls and the vertical line play an important role in determining the ideal log diameter, which is related to the production capacity of the rewinder. Additionally, the ideal roll gap has a significant effect on the spatial distribution of the three rewinding rolls, the rewinding dead zone, and the rewinding quality of the log, which should be taken into full consideration when designing and improving rewinders to enhance production efficiency and satisfy ultra-high quality requirements.展开更多
文摘In this paper, the influence of low power factor on electricity system and the influence of paper breaking on heat system are presented. For that, a mathematical model and a case study for a paper mill are realised. The electric mathematical model is based on the relations of energy losses in cables and in transformers as a function of power factor. The thermal mathematical model includes characteristic energy and efficiency of boiler depending on its load. Characteristic of efficiency is modeled by a quadratic dependence between fuel consumption and steam flow. In the case, study were estimated to reduce energy losses for factor neutral （0.92） against real power factor （0.75） for the electrical scheme of a paper machine. Analytical expression of the boiler characteristic and variation of boiler efficiency depending on its load were estimated, too.
文摘By dividing the rewinding process of a three-roll rewinder into three zones, mathematical equations were formulated and diagrams were drawn to determine the structure factors of the rewinder, such as the diameters and spatial distribution of the rewinding rolls. The qualitative and quantitative analysis results show that the roll gap of the first two rewinding rolls and the angle between the line that connects the center points of the first two rewinding rolls and the vertical line play an important role in determining the ideal log diameter, which is related to the production capacity of the rewinder. Additionally, the ideal roll gap has a significant effect on the spatial distribution of the three rewinding rolls, the rewinding dead zone, and the rewinding quality of the log, which should be taken into full consideration when designing and improving rewinders to enhance production efficiency and satisfy ultra-high quality requirements.
