Kraft biopulping of Eucalyptus grandis

Cerff, Craig Bradley (1999-12)

Thesis (M.Sc.)--University of Stellenbosch, 1999.

Thesis

ENGLISH SUMMARY: Biotechnology has been earmarked as the field that will shape the future of the world as we know it and its advance has not excluded the pulp and paper industry. The importance of biotechnology in the paper industry is emphasized by the large amount of research that has been performed in the various fields of its application ranging from biopulping, biobleaching to deinking technology. However, biopulping research has focused on biomechanical pulping, while little attention has been placed on chemical . pulping methods and the advantages derived from fungal pre-treatment. Therefore, the effect ofthe pretreatment of Eucalyptus grandis wood chips, with white-rot fungi, on the Kraft pulping process was investigated. Eucalyptus grandis is the predominant hardwood species used in the pulp and paper industry of South Africa. Initially a screening program was performed in order to evaluate the biopulping potential of 100 different fungal cultures, isolated in South Africa. Wood chips were inoculated with selected fungal cultures and incubated for a two-week period, at the relevant optimum growth temperatures, under aseptic conditions. Bio-degraded wood chips were pulped by means of the Kraft pulping process and the resultant pulp and black liquor were analysed for yield, shives, kappa number and residual active alkali. Twelve cultures, which showed the most potential for biopulping, were selected from the screening program for further evaluation and statistical validation. Results indicate that certain selected cultures affect significant improvements in the residual active alkali of just under 21%, while the kappa number was reduced by just less than 9%. Under the prevailing conditions, the chemical consumption decreased significantly by ca. 2%. No significant differences, between the test cultures and the control, were observed for yield and shive content. These results prove conclusively that Kraft biopulping of Eucalyptus grandis wood chips has a significantly positive effect on the pulp produced by this process~The-itnplication of savings in both pulping and bleaching chemicals are enormous. It is strongly suggested that a mill-scale trial be performed, upon which a full investigation into the financial implications of Biokraft pulping should be determined.

AFRIKAANSE OPSOMMING: Biotegnologie word as 'n veld beskou wat die toekoms van die wereld kan verander. Die vooruitgang het nie die pulp en papier bedryf onaangeraak gelaat nie. Die belang van biotegnologie vir die papierbedryf word beklemtoon deur die groot hoeveelheid navorsing wat in die verskillende aanwendingsgebiede, soos bioverpulping, biobleiking en ontinkingtegnologie, plaasgevind het. Bioverpulpingsnavorsing het egter gekonsentreer op biomeganiese verpulping, terwyl min aandag aan chemiese verpulpingsmetodes en die voordele verbonde aan fungale voorafbehandeling gegee is. Daarom is die effek wat voorafbehandeling van Eucalyptus grandis houtspaanders, met witverottingsfungi, op die Kraft verpulpingsproses het, ondersoek. Eucalyptus grandis is die vernaamste loofhoutspesies in die pulp en papierbedryf van SUid-Afrika. Eerstens is In siftingsprogram uitgevoer om die bioverpulpingspotensiaal van 100 verskillende funguskulture, wat in Suid-Afrika ge"isoleer is, te evalueer. Houtspanders is toe met geselekteerde funguskulture geinokuleer en vir 'n tweeweeklange periode, by optimale groeitemperature en onder aseptiese toestande, ge"inkubeer. Die houtspaanders wat sooende deur die fungus afgebreek is, is verpulp deur gebruik te maak van die Kraft-proses. Die pulp en swartloog is getoets vir opbrengs, veselbondels, kappa nom mer en oorblywende aktiewe alkali. Die twaalf kulture wat die beste potensiaal vir bioverpulping getoon het, is gekies vir verdere evaluering en statistiese ontleding. Resultate toon aan dat sekere kulture 'n beduidende verbetering in oorblywende aktiewe alkali van ongeveer 21 % bewerkstell het, terwyl die kappa nom mer met net 9% verlaag is. Onder hierdie omstandighede is chemikaliee verbruik met ongeveer 2% verlaag. Geen beduidende verskille is tussen die kultur~ en kontrole gevind in terme van opbrengs en veselbondels nie. Hierdie resultate bewys onomstootlik dat Kraft-bioverpulping van Eucalyptus grandis houtspaanders 'n beduidend positiewe invloed op pulpproduksie toon. Reuse besparings op beide verpulpings- en moontlikke bleikingschemikaliee word deur die resultate geimpliseer. Dit word dus ten sterkste aanbeveel dat In ondersoek op industrieele skaal uitgevoer word, sodat die ekonomiese haalbarheid bepaal kan word.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/51313
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