Runability

Runability and wet end chemistry

There may be several causes why mapping of the wet end is made. One may be to document the normal state, others could be to look for the origin of a problem or to follow up the result of a change made. No matter why, MoRe can put together suitable analyses for the purpose.

To detect and analyze the effects of chemicals in different pulp mixtures and how they work in different stocks is something we have been working with for several years. By deciding where to measure in the wet end of the paper machine and put together a number of suitable analyses, a good mapping of the wet end system is achieved.

Z-potential, cation demand, turbidity, filler content, fines, pH, redox potential, conductivity, dissolved calcium, TOC/COD, chlorides, starch and beating are examples of analyses which could be made. We can also measure dewatering, retention and permeability with our DDA equipment, giving even more information.

It is important to define the normal state of a wet end system for different product types and fiber compositions. If there is a problem on the paper or board machine which is believed to originate from the wet end system, it is good to know the normal condition of the system in order to be able to detect the parameters which deviate and cause the problem. This is also true for changes such as a new wet end chemical, a new filler or a changed pulp mixture. Changes in the production of a certain product often results in consequences for the wet end chemistry which may influence the result negatively. MoRe as a neutral part can assist with the mapping of the wet end chemistry.

When optimizing and characterizing pulps and chemicals we use different types of sheet formers, e.g. the Formette, a dynamic sheet former, but also our experimental paper machine. Also the DDA equipment, Dynamic Drainage Analyzer, developed to simulate dewatering conditions in a paper machine can be used. The effect of different chemicals added to the stock and e.g. beating of the pulps is studied in close cooperation with the mill. The sheets formed can be pressed and dried and be used for e.g. optical measurements such as fluorescence and whiteness. This means that we can study the effect added chemicals e.g. fixatives, has on the fluorescence etc.

Contact: Lars Sundvall +4670-526 52 21 E-mail