Stickies - A Challenge for Process Technology, 1997 Pulping Conference Proceedings

There are a great number of investigations and publications available on the subject of "stickies". Therefore, it is all the more surprising that, in spite of having studied the problems of disturbing substances most thoroughly, some of the suggested solutions and strategies are contradictory, even today.

In this paper, an attempt is made to understand the problem of disturbing substances as a complex problem in papermaking and to coordinate all measures with each other in the overall process. For this purpose, it is necessary to identify all sticky-relevant substances in order to be able to match possible processing steps specifically to each group of substances.

It becomes evident that the measurement of sticky disturbing substances is a fundamental problem. There is no measuring method which supplies a quantifiable "sticky parameter", thus making the test very difficult. As a result, only a multi -dimensional process analysis of all measurable individual parameters can be an adequate basis for the development and optimization of systems.

· A prerequisite for the adequate removal of disturbing substances in the macro range is advanced screening technology in the main flow.

· Dissolved air flotation is best suited for micro substances, but here it is necessary to precisely adjust the chemical pretreatment of the substances to be removed.

· Optimum water management enables dissolved substances and all fines flowing proportionally to the water splits to be controlled as required.

· In addition, all measures must be supplemented by adding a suitable proportion of chemical additives to the entire process. The chemical additives used must be checked for reciprocal action and influence throughout the entire process.