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Water-saving direct mixing of retention aid

Authors:


The boundary conditions for water use are becoming increasingly challenging, even for additive processing systems initially classified as low-consumers, because

  • fresh water withdrawals are increasingly not free of charge,

  • sufficient fresh water quantities are not always available due to climate change,

  • more fresh water means more process heat losses in the wastewater stream,

  • some fresh water qualities can reduce polymer performance, and

  • seasonal fresh water conditions often pose major challenges for process hygiene and reduce the overall efficiency of the plant.

The multidimensional vortex process for mixing in is already known for the very late mixing in of retention agents and pigments. In this case, situations arose where polymer with 2% solids content had to be mixed in directly because existing processing was limited. These first attempts were mostly standardized with success.

A special partner with several projects is the WEIG Group in the Eifel region after the dry summer of 2022.

It started with the construction of a fresh water-reduced powder polymer processing plant from 0.3% to 2%, with an ecowirl injector for each of the two sludge dewatering lines at the power plant.

This was followed by the conversion of the two recirculating water purification systems (flotation systems) in the plant to fresh water-free operation of liquid polymers.

Finally, the retention agent dosing system of the 3-layer board machine was converted. First, a single layer was converted in a trial run for six months, after which all the dosing systems were converted.

The dosing systems in the periphery of the paper machine are briefly discussed and then the challenges on the paper machine are discussed in more detail.

There is also a brief report on the challenges with white papers.

The further development required for the specifications discovered in Mayen for good blending of the ecowirl m on m² and m³ is shown.

Wishes and requirements for polymer qualities are formulated for discussion.