Concept-cell - concepts and developments for pure cellulose production from recycled boards

Today, recycled papers and boards are a major source of sustainable fibers for the papermaking industry. Whereas high paper grades are recycled into writing and printing papers, Old Corrugated Containers (OCC) follow the recycling line of brown pulps to make low quality papers and boards, as they contain mixtures of high quality kraft fibers and low quality, highly lignified fibers and fines.

This project proposes to design new processes for OCC recycling involving a novel concept of chemical pulping aiming to increase the value of OCC in the recycling chain.

This process, which involves a unique delignification operation adapted to isolated recycled fibers instead of wood chips, will enable the use of OCC as a wood substitute to produce high quality cellulose for special grade papers and for the production of paper pulps designed for chemical applications.

In the project, delignification trials are conducted on two OCC models:

• a “wood free OCC model” (American OCC) with low amount of lignin mainly originating from kraft fibers,
• a “wood containing model” (European OCC) with high amount of lignin and a mixture of kraft and native lignin originating from the mechanically obtained pulp fraction.

Several already existing delignification processes such as kraft cooking or oxygen delignification are explored and adapted to this new raw material in order to target a minimum of residual lignin without serious loss of pulping yield and any polysaccharide degradation.

Therefore, two parallel bleaching and purification sequences will be developed using conventional bleaching chemicals (H2O2, ClO2, O3) in either usual or unusual conditions, in combination with pre- or post- treatments when required. The efficiency of the sequence will be assessed in terms of pulp specifications according to the targeted application (paper pulp or pure cellulose).

The aim is to develop new kinetic equations to be incorporated in pulping simulators formerly developed at LGP2 for wood.

This project is expected to offer new perspectives for European and North American pulp mills suffering from the competition of Latin American and South Asian mills having large forest resources at their disposal. The production of high grade cellulose for paper, chemical or textile applications using a low-cost raw material such as OCC would open new markets for pulp producers reinforcing their competitiveness and simultaneously, reducing the export of OCC towards Asian countries.