5 results about "Kappa number" patented technology

The invention provides a model prediction control method for a paper pulp kappa number in a batch cooking process, and belongs to the technical field of pulping and papermaking, the method comprises the following steps: firstly, collecting multi-dimensional measurable state variables related to delignification in the cooking process to form an original state vector; then, utilizing a Koopman operator and extended dynamic mode decomposition to map the original state vector to a high-dimensional linear space to obtain a dimension raising state vector; a Koopman global linear prediction model is established on the basis of historical data offline training, and a free liquid temperature setting sequence in a future control time domain is optimized in a rolling mode through a model prediction controller; the first control quantity of the temperature sequence is applied to the cooking process in real time after each time of optimization, and rolling optimization is repeatedly executed in combination with feedback correction in the next sampling period, so that the problem of steady-state deviation of an end-point kappa value in batch cooking application is solved, and the adaptability to model mismatch and the robustness of a control system are improved.

The invention relates to an environment-friendly brown paper towel and a preparation method thereof, and belongs to the technical field of papermaking. The preparation method comprises the steps of pulping, pulp preparation and drifting, papermaking with a paper machine and the like. By optimizing the pulping process and the fiber combination technology, the performance complementation between the natural color pine pulp with the kappa number of 40 and the chemithermomechanical pulp with the whiteness of 68-72 is realized, so that the finished paper not only keeps the durability of the natural color pine pulp, but also has the soft hand feeling and uniformity of the chemithermomechanical pulp. And meanwhile, the chemical bleaching process of the traditional white hand towel is completely omitted. The method also solves the problem of color uniformity, and can adapt to a fourdrinier double-cylinder paper machine process, so that the environment-friendly brown paper towel is finally obtained.

A packaging paper for sharp-edged objects and / or objects having unevenly arranged, protruding, substantially non-deformable elevations on at least one of the surfaces of the object, consisting of kraft pulp as the main constituent and fillers, starch, sizing agent and additional process aids. The packaging paper containing at least 95% primary pulp having a length-weighted average fiber length of at least 2.0 mm and cationic starch and other process aids. The packaging paper has an elongation at break in the machine direction (MD) according to ISO 1924-3:2005 of at least 6.0%, a puncture energy index according to DIN EN 14477:2004 at a test speed of 10.0 mm / min, measured on any side of the packaging paper, in the range of 30 to 75 mJ·m2 / kg and a kappa number according to ISO 302:2015 of between 35 and 38.

The application provides a model predictive control method for pulp kappa number in batch cooking process, and belongs to the technical field of pulping and papermaking. The method comprises the following steps: first, collecting multi-dimensional measurable state variables related to delignification in the cooking process to form an original state vector; then, using a Koopman operator and extended dynamic mode decomposition, the original state vector is mapped to a high-dimensional linear space to obtain an upgraded state vector; based on historical data offline training, a Koopman global linear prediction model is established, and a free liquid temperature setting sequence in a future control time domain is optimized by a model predictive controller; after each optimization, the first control amount of the temperature sequence is applied to the cooking process in real time, and the rolling optimization is repeatedly executed in combination with feedback correction in the next sampling period. The method overcomes the end-point kappa number steady-state deviation problem existing in batch cooking applications, and improves the adaptability to model mismatch and the robustness of the control system.

The invention pertains to a method for producing multiply paperboard on a paper machine. The process involves forming a paperboard web with a top ply, back ply, and at least one middle ply, where the middle ply consists of at least 40 wt% Chemi-Thermo Mechanical Pulp (CTMP). The back ply is made of at least 80 wt% unbleached kraft pulp with a kappa number of at least 40. The paperboard web undergoes dewatering, pressing, drying, and cooling. It is then calendered in a hard nip with a load ranging from 10-50 kN / m to achieve high smoothness while maintaining the bulk of the paperboard. This method, which incorporates CTMP in the middle ply and high kappa number unbleached kraft pulp in the back ply, benefits from reduced calendering pressures due to pre-cooling, optimizing the paperboard's properties.