Paper Machine Dryer Section Drying Efficiency
Paper machine dryer section is for paper drying, there are two main aspects affecting paper machine drying efficiency: steam pressure and heat transfer coefficient.
Paper Machine Drying Influencing Factors
Steam Pressure: In order to improve drying efficiency, the dryer temperature can be increased by increasing steam pressure, but the maximum pressure used is limited. Most low basic weight printing paper can not use high pressure, especially in the early drying, the beginning pressure should be low, and then gradually increased. Therefore, there is a case that the steam pressure is lower than the atmospheric pressure in the early stage of drying. The pressure is too high easy to make the fiber of paper surface stick to the dryer cylinder, resulting in rough paper and other diseases, and due to inconsistencies separating of paper sheet from the dryer cylinder, there was a problem of paper inequality.
Heat Transfer Coefficient: Heat transfer coefficient is the size of heat transfer resistance, mainly include:
1. Condensation layer thickness and turbulence. (Design factors and regular emissions);
2. Dryer cylinder thickness. (Design factors, drying cylinder scaling);
3. Dryer cylinder surface dirt or fiber. (Doctor blade use, reasonable drying curve and the moisture into dryer);
4. Air trapped between paper sheet and dryer cylinder. (Entering angle, degree of dryer felt tension, dryer felt basis quantify and air permeability);
5. Paper performance. (Basic weight, moisture, thickness, roughness, air permeability, etc.);
6. Non-condensable gas in dryer cylinder. (Design factors and regular emissions)