Pulping and biorefining
- General approach and principles
- Extraction-based methods
- Separation of valuable extractives from trees
- Choosing the right solvent – hydrophobic or hydrophilic?
- Stemwood extractives-based products
- Operation modes and procedures in industrial extraction processes
- Exudate gums and latexes
- Hot-water extraction
- Wood extractives – general description
- Factors contributing to the loss of extractives
- Chemical changes in extractives during storage
- Bark extractives – terpenes and terpenoids
- Bark extractives – polyphenols and other minor compounds
- Use of deep eutectic solvents
- Chemical and biochemical conversion
- Thermochemical conversion
- Kraft pulping
- Wood material handling systems
- Pulping process-general approach
- Pulping technologies
- Drying of chemical pulps
- Chemical (market) pulps drying plant applications
- Recovery of cooking chemicals and by-products
- Integrated biorefinery concepts
- Oxygen-alkali delignification
- Delignifying or lignin-removing bleaching
- Other delignification methods
- Chemimechanical pulping
- Mechanical pulping
- Pulp characterisation and properties
Pressure groundwood pulping (PGW) General approach Pressure groundwood pulping (PGW) is a mechanical pulping process in which wood logs are ground under pressurised conditions (about 2.5 bar) in a grinder at shower water temperatures below 100 °C into wood pulp (Figure 1). The yield of the pulp made by PGW process is about 98.5 %,
Authors & references
Authors:
Raimo Alén, University of Jyväskylä and Victoria Lindqvist, Forest Products Engineers have modified the text mainly from the reference “Karojärvi, R., Haikkala P., Liimatainen, H., Lucander, M. and Tuovinen, O. 2009. Grinding and pressure grinding. In: Lönnberg, B. (Ed.). Mechanical Pulping. 2nd edition. Paper Engineers’ Association, Helsinki, Finland. Pp. 116−173”.
References:
- Karojärvi, R., Haikkala P., Liimatainen, H., Lucander, M. and Tuovinen, O. 2009. Grinding and pressure grinding. In: Lönnberg, B. (Ed.). Mechanical Pulping. 2nd edition. Paper Engineers’ Association, Helsinki, Finland. Pp. 116−173.
- Kärnä, A. 1984. Studies of Pressurised Grinding. Doctoral Thesis. Helsinki University of Technology, Espoo, Finland. 88 p.
- Salmén, L., Lucander, M., Härkönen, E. and Sundholm, J. 2009. Fundamentals of mechanical pulping. In: Lönnberg, B. (Ed.). Mechanical Pulping. 2nd edition. Paper Engineers’ Association, Helsinki, Finland. Pp. 35−67.
- Goring, D. 1963. Thermal softening of lignin, hemicellulose and cellulose. Pulp & Paper Magazine of Canada 65(12):517−527.
- Haikkala, P., Liimatainen, H. and Tuominen, R. 1988. Impact of superheated shower waters on pressure groundwood pulp properties. Proceedings of Appita 1988 Conference, Hobart, Tasmania, Australia. P. A24.1.
- Tuominen, R., Haikkala, P. and Liimatainen, H. 1991. Effect of dry and frozen wood on groundwood pulp quality. Paperi ja Puu 73(4):346−351.
- Haikkala, P., Liimatainen, H. and Tuominen, R. 1999. New grinder concept for continuous pressure grinding. Proceedings of International Mechanical Pulping Conference, Houston, TX, USA. TAPPI Press, Atlanta, GA, USA. Pp. 357−370.
- Tienvieri, T. 2009. Flowsheets for various mechanical pulping and screening processes. In: Lönnberg, B. (Ed.). Mechanical Pulping. 2nd edition. Paper Engineers’ Association, Helsinki, Finland. Pp. 419−429.
- Cariñanco, M., Ramis, E. and Haikkala, P. 2003. Use of Pinus radiata PGW pulp for newsprint and directory papers at Norske Skog Bio mill. Proceedings of 2003 International Mechanical Pulping Conference, June 2−5, 2003, Québec City, Canada. Pp. 463−472.
- Corson, S. and Richardson, J. 2005. Fast grown PGW fibre for superior communication papers. Proceedings of 59th Appita Annual Conference and Exhibition, Aukland, New Zealand, May 16−19, 2005. Pp. 77−84.
- Murtola, C. and Peltonen, E. 1995. Industrielle Druckschlifferzeugung mit niedrigen Spritzwassertemperaturen in einer Papierfabrik. PTS-TUD Symposium Papierzellstof und Holzstofftechnik, Dresden, Germany.
- Asunmaa, P. 1993. The selection, process flowcharts, optimization and results obtained from the new PGW-S mill at the Kaukas Oy, Voikkaa Mill in Finland. Notes of CPPA Annual Meeting, Montréal, Canada. P. B71.
- Honkanen, T. and Yrjönsuuri, R. 1993. The first years of the first PGW-S mill. Proceedings of International Mechanical Pulping Conference, Oslo, Norway. P. 44.
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This page has been updated 25.05.2021