Development of additive transfer and dosing system with straight forward steps improves cleanliness, quality and runnability

摘要

Today there are new effective flash mixing methods for chemicals applied into papermaking processes where several chemicals and additives can be brought to the process area close to the dewatering and forming section between machine screen and the headbox. The novel advantageous concept sets new quality requirements for supporting sub processes like chemical transfer systems to make the best out of it with excellent runnability. Fillers, chemicals, filtrates or water that are inserted into the process to post-screen location go directly through headbox to the forming section and to the end product. Thus a good cleanliness of the whole part of the dosing process is a must to guarantee cleanliness of the end product and for trouble free runnability. Additive quality and stability is also very important and essential. With conventional systems scaling on surfaces, dirt build up. lumps, fiber spinning and stabilization happens easily. Conditions how to prepare, transfer and dose additives can be evaluated and updated to meet good runnability and cleanliness targets. This results in a clean overall process, good runnability and net efficiency of production. Problem findings from running production plants will be presented together with new developed system improvements and guidelines to audit and develop the process. Dirt build cases, transfer piping set-up, pumping, flushing cleaning and filtering concepts describe straight forward practices how to maintain or meet the cleanliness and good runnability targets.