Status: Need is Closed

Preventing Lignin from Fouling Processing Equipment

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Need was closed on
Nov 7, 2019

Stora Enso, a renewable material manufacturer, is looking for technical solutions or processing steps that prevent the lignin from fouling their equipment when processing their acidic pre-hydrolysis liquors.


Stora Enso uses the Kraft process to convert wood into pulp, which consists of almost pure cellulose fibers. As a first step, Hardwood chips are pretreated with hot water (150 – 200°C) to remove hemicelluloses (i.e. pre-hydrolysis). Together with hemicelluloses, also significant amounts of organics (such as lignin) or minerals (such as calcium) are dissolved in the acidic pre-hydrolysis liquor (PHL).
To reduce the waste streams generated by this Kraft process, the liquors are further processed, and the solid faction of the liquor is concentrated up to at least 30%.  One of the issues that comes along with this is that, when cooling down the PHL, the lignin precipitates and fouls most parts of the processing equipment, resulting in systematic shutdowns for maintenance and cleaning.
For this reason, Stora Enso is looking for solutions that prevent the lignin from fouling their equipment when processing the pre-hydrolysis liquors.

Key success Criteria
  • Reduce the amount of lignin fouling the equipment or reduce the concentration of lignin in the PHL from >10 g/L to 3 g/L
  • Allow concentrating the PHL to at least 30% solid faction at 60°C
  • After development, the solution should be scalable to 400 m³ production units
Possible Approaches

Potential approaches could be, but are not limited to:

Anti-fouling technologies that prevent the lignin from fouling to the equipment’s surface

  • Surface coatings
  • Surface microstructuring
  • Additives preventing lignin foulant
  • Plasma treatments, …

Online cleaning technologies

  • Ultrasonic solutions
  • Additives removing lignin foulant,…

Methods for lowering/removing solid lignin content in the PHL

  • Clogging resistant ultrafiltration filters
  • Ultrafiltration technologies that are not blocked by precipitates or minerals
  • Additives that keep lignin ‘dissolved’
  • Electroplating
Approaches not of Interest
  • Ultrafiltration methods that are easily blocked by precipitates of minerals
  • Activated carbon
Due Date
Oct 31, 2019
Items to be submitted
  • Describe the approach/technology
  • How the technology is relevant to our current challenge?
    • Which key criteria can your solution meet?
  • Level of maturity of the technology (development stage or just a proposal)
  • How adaptable is the technology, can it be optimized?
  • Description of your organization
  • Background information on the people involved in the proposal
Gallery Moderator(s)
Tom Vranken
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Area of Interest