The more advanced cooking technology and equipment in the world include the improved continuous digester and isothermal digester from Norway. Their biggest feature is that the kappa value of the crude pulp after cooking is low (up to 25), but it does not reduce the pulp strength. In terms of batch cooking, cold spray technology is more prominent. It is characterized by low energy consumption, high pulp yield, and greatly increased cooking capacity compared to traditional methods.
From the perspective of development, cooking technology will develop and apply deep cooking technology on the basis of expanded and improved kraft cooking to reduce the kappa value of coarse pulp, reduce energy consumption and reduce pollution. Sulfur-free pulping will also be a direction of future development.
In recent years, the new technology adopted in the world is element-free chlorine bleaching technology (referred to as ECF technology), and completely chlorine-free bleaching technology (referred to as TCF technology) has been gradually applied. Compared with the traditional methods, these two bleaching methods have the greatest advantage of greatly reducing environmental pollution. In traditional chlorine-containing bleaching, the content of AOX in wastewater is 2.4 kg/ton of pulp, while using ECF technology and TCF technology, the content of AOX in wastewater is 0.6 kg/ton of pulp and 0.2 kg/ton of pulp,respectively.
In addition, the use of ozone, hydrogen peroxide, biological enzymes, etc. as bleaching agents to treat pulp will also be the development direction of bleaching technology in the future.
