Pulp washing: Influence of temperature on lignin leaching from kraft pulps
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Gunnar Eriksson
Abstract
The leaching of lignin from the fibre wall was studied in order to investigate the effects in the clean end of the fibre line. The focus was set on the short time intervals representative for the washing operation in industrial applications. The influence of temperature, pulp type and kappa number was investigated. It could be seen that there are different diffusivities for the soluble lignin in the wall at short and long time of leaching, probably due to the existence of a more open structure in an outer layer of the fibre wall, in which the lignin diffuses more easily and which is also emptied relatively fast, while diffusion of the lignin from the inner layers is significantly slower. There is also a relation between the leaching of sodium ions out of the wall and the short diffusion time of lignin, indicating a possible ion-ion interaction with the lignin in the outer layer of the fibre wall. The diffusivity of lignin increases more rapidly at temperatures above 80-90 "C. This temperature effect was confirmed in the results of wash test equipment experiments, giving noticeable differences above 100 "C. It was found that the experimentally determined lignin diffusivity differs for different kappa number and for type of pulp. The general behaviour of the phenomena, however, is the same.
© 2018 by Walter de Gruyter Berlin/Boston
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Artikel in diesem Heft
- Lamellar cracks, do they appear during radial compression of wood?
- Characterization of surfaces of CTMP fibers using inverse gas chromatography combined with multivariate data analysis
- Residual phase lignin in haft cooking related to the conditions in the cook
- Fibre characteristics and paper properties of formic acid / peroxyformic acid birch pulps
- Pulp washing: Influence of temperature on lignin leaching from kraft pulps
- Effect of headbox slice geometry during the stratified forming of woodfree paper
- Surface characterization of a rosin sizing agent in paper by means of EPMA, ESCA and TOF-SIMS
- The steady-state compressibility of saturated fibre webs at low pressures
- Dynamic simulation of a thermomechanical pulp refiner
- Identification of carton board qualities using gas chromatography or gas sensitive sensors in combination with multivariate data analysis
- Thermodynamic parameters governing the stereoselective degradation of arylglycerol-B-aryl ether bonds in milled wood lignin under kraft pulping conditions
- Calendering of coated paper and board in an extended soft nip
- List of dissertations in the field of pulp and paper 1996 (previously not published) and 1997
- Annual index for 1997
