A critical pathway towards enhancing pulp mill biorefineries is to integrate the extraction and utilization of hemicelluloses into the pulping processes.Hence,an industrial pre-extraction strategy for hemicelluloses t...A critical pathway towards enhancing pulp mill biorefineries is to integrate the extraction and utilization of hemicelluloses into the pulping processes.Hence,an industrial pre-extraction strategy for hemicelluloses targeting eucalyptus kraft pulping process was developed.Alkaline solution or pulping white liquor was used to pre-extract hemicelluloses before the actual pulping process.The response surface methodology(RSM)technique was applied to investigate the most suitable conditions to maximize the yield of these hemicelluloses while simultaneously minimizing the damage to pulp yields and properties.Temperature(105 to 155℃),alkali concentration(3%to 8%),sulfidity(20%to 30%)and retention time(19 to 221 min)were combined to evaluate their effects on hemicellulose yields and chemical structures.The optimal pre-extraction conditions identified in this work(5.75%NaOH concentration,25%sulfidity at 135℃for 60 min)successfully allowed recovering 4.8%of hemicelluloses(based on the wood dry mass)and limited damages to pulp yields and properties.The cellulose content in pulp can even be increased by about 10%.Hemicellulose emulsification properties were also evaluated,which were comparable to synthetic emulsifiers.This study provides an industrial pathway to effectively separate and utilize wood hemicelluloses from the pulping process,which has the potential to improve the economy and material utilization of pulp and paper mills.展开更多
Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually prese...Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually present as a spent liquor,such as the prehydrolysis liquor of the prehydrolysis kraft dissolving pulp production process and the alkali extraction liquor of the cold caustic extraction of pulp fibers.Due to its dilute nature,hemicellulose needs to be dried for practical utilization,and this is challenging.In this study,cellulose and hemicellulose in a bleached bamboo kraft pulp were separated using an alkali extraction process.Hemicellulose obtained from the extraction liquor was dried by an ammonium carbonate-assisted drying process.The effects of drying time and drying temperature were determined.Structure of the hemicellulose obtained by the ammonium carbonate-assisted drying process was similar to that of original hemicellulose,as revealed by detailed Fourier transform infrared and X-ray diffraction analyses.The novel drying method was more energy efficient and required a shorter drying time than the conventional freeze drying method,and the excellent solubility in alkaline solutions favored the chemical modification of hemicellulose.The dried hemicellulose can be used as a renewable raw material for the preparation of hydrogels and other substances such as bioethanol/biochemicals and biodegradable films.展开更多
By applying ultrasound at different stage of kraft pulping process, the properties of kraft pulp produced by ultrasonic treatment were studied and compared with those by conventional method. The results indicated that...By applying ultrasound at different stage of kraft pulping process, the properties of kraft pulp produced by ultrasonic treatment were studied and compared with those by conventional method. The results indicated that, while the performances of the pulp were close to conventional kraft pulp, the chemical-to-wood ratio decreased from 20% to 17.5%, cooking time was shortened from 140 to 120 rain, and the yield increased. When the ultrasound came into play at the 90th minute during pulping process, the properties of the produced bamboo fiber were the most desirable.展开更多
This study indicated that by applying an improved classification system to decayed large-diameter Norway spruce(Picea abies)wood,its use as raw material for kraft pulping without loss of pulp quality could be essentia...This study indicated that by applying an improved classification system to decayed large-diameter Norway spruce(Picea abies)wood,its use as raw material for kraft pulping without loss of pulp quality could be essentially increased.This is based on the fact that although the cooking yield of decayed spruce material which has been sorted according to these new recommendations is somewhat lower and Kappa number higher than those of sound wood material,the greatest part of the decayed stem(the outer part of the stem)contains long-fiber wood material which produces pulp of good quality.Therefore,large-diameter spruce logs can also be separately used,for example,in the manufacture of reinforcement pulp.展开更多
In integrated factories of pulp and paper, the bleaching control is made by kappa number and/or brightness. However, the product paper is evaluated and valued for its whiteness. The level of final brightness of pulp c...In integrated factories of pulp and paper, the bleaching control is made by kappa number and/or brightness. However, the product paper is evaluated and valued for its whiteness. The level of final brightness of pulp certainly affects the demand for optical brighteners in paper manufacturing, nevertheless, there is not a direct correlation between consumption of optical brightener and final brightness, being the method of bleaching pulp, especially from the final stage of bleaching, also important in relation to this demand. Therefore, this study aimed to evaluate the potential of using the parameter whiteness as a tool to control bleaching pulp, instead of the traditional brightness and evaluate the impacts of different methods of bleaching and the pulp final brightness level in action of optical brighteners, to improve their performance. It was observed that the whiteness and brightness of the pulp are highly correlated and that the control of the bleaching plant can be done by any one of these two parameters. It was also concluded that, considering current prices of bleaching reagents and of optical brighteners, it is better to bleach the pulp up to lower brightness values (e.g. 88% ISO) and use larger amounts of optical brighteners to brighten the mass until the whiteness of 130 CIE. This conclusion is valid for whiteness measured before the size press. Further studies are needed to validate this conclusion considering the finished product.展开更多
This study presents hybrid clones of Corymbia spp.developed by Aperam BioEnergia as potential substitutes for Eucalyptus wood in the pulp industry.The biomass of Eucalyptus spp.was compared with that of Corymbia spp.b...This study presents hybrid clones of Corymbia spp.developed by Aperam BioEnergia as potential substitutes for Eucalyptus wood in the pulp industry.The biomass of Eucalyptus spp.was compared with that of Corymbia spp.by performing modified kraft pulping and basic density analyses.Comparisons were made by analyzing their respective mean annual increments of cellulose(MAI_(cel))and specific wood consumption(SWC),estimated using a kappa number of(19±1).The results showed that one of the hybrid clones(Corymbia citriodora×Corymbia torelliana,ID 4)had higher basic wood density,higher screened yield,better MAI_(cel#k19),and lower SWC than the other samples,reaching values of 0.608 t/m^(3),54.1%,24.6 ADt/ha/year(i.e.,air dry ton/hectare/year),and 2.74 m^(3)/ADt,respectively.Consequently,clone ID 4 had the highest MAI_(cel)/SWC ratio score(8.98).Given its high forest productivity and low industrial cost compared with other samples,as well as its advantages over Eucalyptus spp.wood,we concluded that clone ID 4 has great potential as an alternative biomass for pulp production.展开更多
Three-dimensional(3D)printing is a useful technique that allows the creation of objects with complex structures by deposition of successive layers of material.These materials are often from fossil origin.However,effor...Three-dimensional(3D)printing is a useful technique that allows the creation of objects with complex structures by deposition of successive layers of material.These materials are often from fossil origin.However,efforts are being made to produce environmentally friendly materials for 3D printing.The addition of lignocellulosic fibres to a polymer matrix is one of the alternatives to replace,for instance,glass fibres in composites as reinforcing materials.The fields of biocom-posites and 3D printing open innovative application areas for pulp fibres from the pulp and paper industry.In this work,biocomposites of poly(lactic acid)(PLA),poly(hydroxyalkanoate)(PHA)and kraft pulp fibres were prepared in order to find a suitable formulation for filaments for 3D printing.The effect of two different types of kraft fibres(bleached(B)and unbleached(U))and of PHA on the mechanical and thermal properties of the biocomposites was assessed.The addition of 30%kraft fibres to PLA resulted in an increase of the tensile modulus from 3074 to∼4800 MPa.In the case of biocomposites containing PHA(50%PLA/20%PHA/30%kraft)the increase in modulus was more moderate(PLA+PHA+U:3838 MPa,and PLA+PHA+B:3312 MPa).The tensile strength of PLA(66 MPa)increased to 77 MPa in PLA+kraft biocomposites,while a reduc-tion in strength was observed for PLA+PHA+U(43 MPa)and PLA+PHA+B(32 MPa).Filaments prepared with PLA,PHA and bleached and unbleached pulp fibres showed similar printability of complex geometries,demonstrating that unbleached pulp fibres could also be utilized in the preparation of biocomposites with good mechanical performance and 3D printing properties.展开更多
In this paper, calcium carbonate waste was recovered as paper filler from the causticizing process of bamboo kraft pulping. The effects of the causticizing process parameters on the filler qualities were investigated,...In this paper, calcium carbonate waste was recovered as paper filler from the causticizing process of bamboo kraft pulping. The effects of the causticizing process parameters on the filler qualities were investigated, in terms of the whiteness, tear strength, tensile strength and ash content of the filled paper. To investigate the effect of silica content on the qualities of the resultant calcium carbonate filler, the green liquor was desiliconized with aluminum salt modified bentonite prior to the causticizing process to obtain calcium carbonate of various silicon contents, particle size and brightness, and different crystal morphology. It was found that the ionic strength and silicate concentration were the two key factors in affecting the size and shape of the calcium carbonate particles formed in the causticizing process.展开更多
The objective of this work is to systematically evaluate the performance of the hydrolysis-based kraft pulping process and associated pulp and black liquor characteristics.Acacia wood chips were auto-hydrolyzed under ...The objective of this work is to systematically evaluate the performance of the hydrolysis-based kraft pulping process and associated pulp and black liquor characteristics.Acacia wood chips were auto-hydrolyzed under various severities,then the hydrolyzed wood chips were kraft pulping.The results indicated that the yield of pulp significantly dropped with intensifying the auto-hydrolysis severity.Meanwhile,the removal rate of pentosan reached 98.6%in the screened pulp at the P-factor of 1000.The fiber length,fines and fiber crimp of the screened pulp were not affected by the auto-hydrolysis treatment.Auto-hydrolyzed pulps deteriorated fibrillation and beating response of the pulp in a refining process.However,fiber length and fines changed obviously after beating treatment.After auto-hydrolysis,the tensile index of the paper matrices decreased,some particle substances were found on the surface of the pulp fiber,and the solid and organic content of the black liquor were improved.展开更多
China’s first modern kraft pulping production line with an annual capacity of 150,000 tons unbleached pulp in Qingshan Paper Industry Co., Ltd ., Fujian Province has been recently accepted by the State. As a chief de...China’s first modern kraft pulping production line with an annual capacity of 150,000 tons unbleached pulp in Qingshan Paper Industry Co., Ltd ., Fujian Province has been recently accepted by the State. As a chief designer and project manager, the author reviews the course which the project has covered from 1985, when the project feasibility study was conducted on the grant offered by Sweden Government to July, 1994, when such a large kraft pulping production line equipped with the most up-to-date technological process and machinery available in the world at the beginning of 1990’s was put into operation. In the spirit of seeking truth from facts, the author also points out shortcomings of the project design which need to be overcomed in the future and the improvements that have been made since the project was put into operation. The author has also aired her opinions on how to digest the foreign advanced technologies and how to improve the foreign equipment for the Chinese pulp and paper industry.展开更多
基金supported by the Natural Science Foundation of Guangdong Province(2023A1515030211)the National Natural Science Foundation of China(22278157)Guangzhou Science and Technology Program(2023B03J1365).
文摘A critical pathway towards enhancing pulp mill biorefineries is to integrate the extraction and utilization of hemicelluloses into the pulping processes.Hence,an industrial pre-extraction strategy for hemicelluloses targeting eucalyptus kraft pulping process was developed.Alkaline solution or pulping white liquor was used to pre-extract hemicelluloses before the actual pulping process.The response surface methodology(RSM)technique was applied to investigate the most suitable conditions to maximize the yield of these hemicelluloses while simultaneously minimizing the damage to pulp yields and properties.Temperature(105 to 155℃),alkali concentration(3%to 8%),sulfidity(20%to 30%)and retention time(19 to 221 min)were combined to evaluate their effects on hemicellulose yields and chemical structures.The optimal pre-extraction conditions identified in this work(5.75%NaOH concentration,25%sulfidity at 135℃for 60 min)successfully allowed recovering 4.8%of hemicelluloses(based on the wood dry mass)and limited damages to pulp yields and properties.The cellulose content in pulp can even be increased by about 10%.Hemicellulose emulsification properties were also evaluated,which were comparable to synthetic emulsifiers.This study provides an industrial pathway to effectively separate and utilize wood hemicelluloses from the pulping process,which has the potential to improve the economy and material utilization of pulp and paper mills.
基金the National Key Research and Development Program of China(2017YFB0307900,2019YFC1905903)the National Natural Science Foundation of China(31700507)the Major Project on the Integration of Industry-Education-Research of Fujian Provincial Department of Science and Technology(2018H6003).
文摘Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually present as a spent liquor,such as the prehydrolysis liquor of the prehydrolysis kraft dissolving pulp production process and the alkali extraction liquor of the cold caustic extraction of pulp fibers.Due to its dilute nature,hemicellulose needs to be dried for practical utilization,and this is challenging.In this study,cellulose and hemicellulose in a bleached bamboo kraft pulp were separated using an alkali extraction process.Hemicellulose obtained from the extraction liquor was dried by an ammonium carbonate-assisted drying process.The effects of drying time and drying temperature were determined.Structure of the hemicellulose obtained by the ammonium carbonate-assisted drying process was similar to that of original hemicellulose,as revealed by detailed Fourier transform infrared and X-ray diffraction analyses.The novel drying method was more energy efficient and required a shorter drying time than the conventional freeze drying method,and the excellent solubility in alkaline solutions favored the chemical modification of hemicellulose.The dried hemicellulose can be used as a renewable raw material for the preparation of hydrogels and other substances such as bioethanol/biochemicals and biodegradable films.
文摘By applying ultrasound at different stage of kraft pulping process, the properties of kraft pulp produced by ultrasonic treatment were studied and compared with those by conventional method. The results indicated that, while the performances of the pulp were close to conventional kraft pulp, the chemical-to-wood ratio decreased from 20% to 17.5%, cooking time was shortened from 140 to 120 rain, and the yield increased. When the ultrasound came into play at the 90th minute during pulping process, the properties of the produced bamboo fiber were the most desirable.
基金The authors wish to thank Mittaportti Oy for the log classification,Metsäteho Oy for the rot determinations,and Western Laboratories Inc.for the pulp strength analyses.
文摘This study indicated that by applying an improved classification system to decayed large-diameter Norway spruce(Picea abies)wood,its use as raw material for kraft pulping without loss of pulp quality could be essentially increased.This is based on the fact that although the cooking yield of decayed spruce material which has been sorted according to these new recommendations is somewhat lower and Kappa number higher than those of sound wood material,the greatest part of the decayed stem(the outer part of the stem)contains long-fiber wood material which produces pulp of good quality.Therefore,large-diameter spruce logs can also be separately used,for example,in the manufacture of reinforcement pulp.
基金Funding provided by the Minas Gerais State Research Foundation(FAPEMIG)from the Brazilian National Council for Science and Technology Development(CNPq)is greatly appreciated.
文摘In integrated factories of pulp and paper, the bleaching control is made by kappa number and/or brightness. However, the product paper is evaluated and valued for its whiteness. The level of final brightness of pulp certainly affects the demand for optical brighteners in paper manufacturing, nevertheless, there is not a direct correlation between consumption of optical brightener and final brightness, being the method of bleaching pulp, especially from the final stage of bleaching, also important in relation to this demand. Therefore, this study aimed to evaluate the potential of using the parameter whiteness as a tool to control bleaching pulp, instead of the traditional brightness and evaluate the impacts of different methods of bleaching and the pulp final brightness level in action of optical brighteners, to improve their performance. It was observed that the whiteness and brightness of the pulp are highly correlated and that the control of the bleaching plant can be done by any one of these two parameters. It was also concluded that, considering current prices of bleaching reagents and of optical brighteners, it is better to bleach the pulp up to lower brightness values (e.g. 88% ISO) and use larger amounts of optical brighteners to brighten the mass until the whiteness of 130 CIE. This conclusion is valid for whiteness measured before the size press. Further studies are needed to validate this conclusion considering the finished product.
文摘This study presents hybrid clones of Corymbia spp.developed by Aperam BioEnergia as potential substitutes for Eucalyptus wood in the pulp industry.The biomass of Eucalyptus spp.was compared with that of Corymbia spp.by performing modified kraft pulping and basic density analyses.Comparisons were made by analyzing their respective mean annual increments of cellulose(MAI_(cel))and specific wood consumption(SWC),estimated using a kappa number of(19±1).The results showed that one of the hybrid clones(Corymbia citriodora×Corymbia torelliana,ID 4)had higher basic wood density,higher screened yield,better MAI_(cel#k19),and lower SWC than the other samples,reaching values of 0.608 t/m^(3),54.1%,24.6 ADt/ha/year(i.e.,air dry ton/hectare/year),and 2.74 m^(3)/ADt,respectively.Consequently,clone ID 4 had the highest MAI_(cel)/SWC ratio score(8.98).Given its high forest productivity and low industrial cost compared with other samples,as well as its advantages over Eucalyptus spp.wood,we concluded that clone ID 4 has great potential as an alternative biomass for pulp production.
基金The authors thank Elopak AS and the Research Council of Norway for funding(NEPP project Grant:309441)。
文摘Three-dimensional(3D)printing is a useful technique that allows the creation of objects with complex structures by deposition of successive layers of material.These materials are often from fossil origin.However,efforts are being made to produce environmentally friendly materials for 3D printing.The addition of lignocellulosic fibres to a polymer matrix is one of the alternatives to replace,for instance,glass fibres in composites as reinforcing materials.The fields of biocom-posites and 3D printing open innovative application areas for pulp fibres from the pulp and paper industry.In this work,biocomposites of poly(lactic acid)(PLA),poly(hydroxyalkanoate)(PHA)and kraft pulp fibres were prepared in order to find a suitable formulation for filaments for 3D printing.The effect of two different types of kraft fibres(bleached(B)and unbleached(U))and of PHA on the mechanical and thermal properties of the biocomposites was assessed.The addition of 30%kraft fibres to PLA resulted in an increase of the tensile modulus from 3074 to∼4800 MPa.In the case of biocomposites containing PHA(50%PLA/20%PHA/30%kraft)the increase in modulus was more moderate(PLA+PHA+U:3838 MPa,and PLA+PHA+B:3312 MPa).The tensile strength of PLA(66 MPa)increased to 77 MPa in PLA+kraft biocomposites,while a reduc-tion in strength was observed for PLA+PHA+U(43 MPa)and PLA+PHA+B(32 MPa).Filaments prepared with PLA,PHA and bleached and unbleached pulp fibres showed similar printability of complex geometries,demonstrating that unbleached pulp fibres could also be utilized in the preparation of biocomposites with good mechanical performance and 3D printing properties.
文摘In this paper, calcium carbonate waste was recovered as paper filler from the causticizing process of bamboo kraft pulping. The effects of the causticizing process parameters on the filler qualities were investigated, in terms of the whiteness, tear strength, tensile strength and ash content of the filled paper. To investigate the effect of silica content on the qualities of the resultant calcium carbonate filler, the green liquor was desiliconized with aluminum salt modified bentonite prior to the causticizing process to obtain calcium carbonate of various silicon contents, particle size and brightness, and different crystal morphology. It was found that the ionic strength and silicate concentration were the two key factors in affecting the size and shape of the calcium carbonate particles formed in the causticizing process.
基金supported by Natural Science Foundation of China(No.31971608)Natural Science Foundation of Liaoning Province(No.2019-ZD-0125)+1 种基金Liaoning Baiqianwan Talents Program(No.2019)Innovative Talents in Liaoning Uni-versities and Colleges(No.2020).
文摘The objective of this work is to systematically evaluate the performance of the hydrolysis-based kraft pulping process and associated pulp and black liquor characteristics.Acacia wood chips were auto-hydrolyzed under various severities,then the hydrolyzed wood chips were kraft pulping.The results indicated that the yield of pulp significantly dropped with intensifying the auto-hydrolysis severity.Meanwhile,the removal rate of pentosan reached 98.6%in the screened pulp at the P-factor of 1000.The fiber length,fines and fiber crimp of the screened pulp were not affected by the auto-hydrolysis treatment.Auto-hydrolyzed pulps deteriorated fibrillation and beating response of the pulp in a refining process.However,fiber length and fines changed obviously after beating treatment.After auto-hydrolysis,the tensile index of the paper matrices decreased,some particle substances were found on the surface of the pulp fiber,and the solid and organic content of the black liquor were improved.
文摘China’s first modern kraft pulping production line with an annual capacity of 150,000 tons unbleached pulp in Qingshan Paper Industry Co., Ltd ., Fujian Province has been recently accepted by the State. As a chief designer and project manager, the author reviews the course which the project has covered from 1985, when the project feasibility study was conducted on the grant offered by Sweden Government to July, 1994, when such a large kraft pulping production line equipped with the most up-to-date technological process and machinery available in the world at the beginning of 1990’s was put into operation. In the spirit of seeking truth from facts, the author also points out shortcomings of the project design which need to be overcomed in the future and the improvements that have been made since the project was put into operation. The author has also aired her opinions on how to digest the foreign advanced technologies and how to improve the foreign equipment for the Chinese pulp and paper industry.
