Energy Saving in Paper Machine Vacuum System

-How to Utilize Modern Process and Variable Speed Drive Technology-

Abstract

Energy prices are soaring beyond all expectations. On the other hand, new technologies are emerging to tackle this challenge. But how much energy can be saved without putting paper production at risk? In the paper industry, we are use to-for a good reason-to be rather conservative in applying new inventions. Savings and cost factors tend to be marginal in relation to the overall cost and income. Any disturbance in production, however, will cost a lot in lost profits.
The rising price of energy is putting pressure on paper production costs. Besides the pulp production, the paper machine line consumes a significant amount of energy. When the production volumes are high, the process equipment is a heavy user of energy. From this process equipment, the big pumps and paper machine line drives are the heavy users of energy. New technologies in process design, pumping principles and variable speed electric drives can cut the pumping energy bill dramatically.
Vacuum pump choice and mode of operation also has a significant impact on energy consumption. High power consumption is needed to produce the paper machine vacuums, needed in drainage and web handling, i. e. for the suction boxes and the suction rolls. Further on, these vacuum elements often represent a big portion of the friction increasing machine drive loads. Dimensioning the system can be a tricky task, because so many variables are involved, and many of them (such as raw material, water, water temperatures) are often beyond the control-at least beyond economical control-of the machine personnel. By utilizing energy efficient pumping principles and controllable technology, this obstacle can be overcome.