A modern paper machine is an integrated system of interconnected sections designed to transform pulp into a continuous paper web. Its main components include the headbox, forming section, press section, dryer section, calender, and reel, supported by auxiliary systems for steam, water, vacuum, lubrication, and heat recovery.
The core manufacturing process comprises four primary stages: forming, pressing, drying, and calendering. First, a pulp suspension meeting specific requirements is evenly discharged from the headbox onto a moving forming fabric (such as a Fourdrinier wire, cylinder mold, or twin-wire former); water drains through the mesh while fibers interlace to form a wet paper web. Next, the wet web enters the press section, where mechanical dewatering via pressure rolls (e.g., stone and rubber rolls) reduces the moisture content to approximately 50%. Following this, the sheet enters the dryer section and passes over a series of steam-heated drying cylinders, raising the dryness level to 92–94%.
Finally, the paper undergoes surface finishing in the calender to improve smoothness and density before being wound into rolls. The papermaking process relies heavily on auxiliary systems-such as water, steam, and vacuum-and emphasizes white water circulation and heat recovery to enhance energy efficiency. The relative costs of dewatering in the forming, press, and dryer sections are approximately 1:70:330; consequently, improving dewatering efficiency in the forming and press sections is crucial for reducing overall energy consumption.
