Supply Strategy of Fiber Sources for China’s Paper Industry under Policies of Restriction Usage of Plastic and Banning Solid Wastes Importation

FANG Guigan,SHEN Kuizhong,LI Xiaoliang,SHI Junqi

2021,(7):1-7.DOI:10.11980/j.issn.0254-508X.2021.07.001

Recycled fibers are main fibrous raw materials for China's papermaking industry， accounting for 56.6% of the total fiber raw material consumption. The implementation of the banning solid wastes importation policy would lead to a supplying shortage of nearly 30 million tons of fibers. In 2025， the restriction polices on the usage of plastic as packaging materials will be executed， therefore， there will be a new consumption demand of about 8.5 million tons of paper and paperboard instead of plastic for the paper industry. It was predicted that the consumption demand of paper and paperboard for China's market would be increased up to about 120 million~130 million tons till 2025. The contradiction of fiber supply and consumption of the fiber sources would be aggravated by the superposition of two factors： the restriction polices on using plastic and the import prohibition on solid wastes. At present， the domestic recycled fiber supply has reached the ceiling， and also the dependence of fiber raw material import being reached a historical high level. It is neither realistic nor feasible to rely too much on the import of wood pulp and chips or to increase the domestic recycled fibers to solve the contradiction between supply and demand of fiber raw materials. The best strategy to deal with the supply risk of fiber raw materials is to improve the supply chain of fibrous raw materials which can be controlled independently. Only by strengthening the integration of forestry， pulp and paper， increasing the supply of domestic pulp， actively developing high yield pulping， including development of non-wood high yield pulping， and establishing the advantages of both the domestic and foreign fiber production distribution for the prepared enterprises. Thus， the supply of fiber raw materials can be completely solved.

[Abstract] [PDF]

Application of MgO as Part of Alkali Source and Substitute for Bleaching Additives in P-RC APMP High Concentration Retention Section

ZHANG Bo,LIU Xin,WU Kaili,WANG Xiaodi,ZHANG Fangdong,LIU Wei,HOU Qingxi

2021,(7):8-14.DOI:10.11980/j.issn.0254-508X.2021.07.002

The effects of substitution of 50% NaOH by MgO in the high-consistency （HC） stage of P-RC APMP without adding chelator DTPA or pH buffer Na2SiO3 on the properties of the resultant pulp and the residual H2O2 content were investigated in this study. The results showed that the obtained P-RC APMP has 15.4% increase in bulk but opacity and strength properties decreased after replacing 50% NaOH with MgO. Compared with the pulp adding DTPA， bulk of the pulp without DTPA reduced by 6.5%. However， the tensile index， burst index and tear index increased by 6.6%， 4.4% and 6.6%， respectively. Moreover， the opacity increased by 10.3%， and the brightness had no significant change （only 0.57% increased）. The residual H2O2 content was 3.55 g/L at the end of bleaching， which was decreased by 5.1%. Therefore， if the property of bulk was not regarded as most important， using MgO as the alkaline source to replace 50% NaOH in the HC stage of P-RC APMP could also replace the chelating agent DTPA at the same time， thereby the need for metal ion chelating agents was eliminated.

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Preparation of Nano TiO2 Composite Fluorescent Whitening Emulsion and Its Application in the Paper

ZHANG Guanghua,WANG Zhe,GUO Mingyuan,NI Meile,HAN Xiaoqian,TONG Xin,WANG Yanmeng,FENG Pengchao

2021,(7):15-23.DOI:10.11980/j.issn.0254-508X.2021.07.003

A triazine amino stilbene fluorescent whitening monomer （FBs） was prepared by using 4，4-diamino-2，2-disulfonic acid stilbene （DSD acid） as the parent and cyanuric trichloride as the bridging agent. FBs， acrylamide， styrene and modified nano TiO2 were copolymerized to obtain nano TiO2 composite fluorescent whitening emulsion （FBs-TiO2）， which was used for paper surface coating. The results showed that FBs-TiO2 was successfully prepared and had better stability. The whiteness increased from 67.2% to 87.2%， the tensile strength was enhanced from 3.12 kN/m to 4.87 kN/m， the tearing strength was increased from 13.8 mN·m2/g to 17.4 mN·m2/g after FBs-TiO2 was coated on paper surface， the PC value decreased from 10.40 to 6.66 after 48 hours of UV aging. It was indicated that the FBs-TiO2 not only improved the whiteness of paper and inhibit the yellowing of paper， but also significantly enhanced the surface strength and mechanical properties of paper. It was a papermaking additive with positive performance.

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Development Status and High-value Application Research Progress of High Yield Pulp

ZHANG Xue,ZHANG Hongjie,CHENG Yun,LIU Xiaofei,LI Lizi,LIU Chengyue

2021,(7):24-32.DOI:10.11980/j.issn.0254-508X.2021.07.004

Pulping and papermaking industry of China has always been facing the shortage of fiber resources. Even worse， with the implementation of the restriction policy on importing solid waste from abroad， the gap of fiber raw material in papermaking industry is further increased. In recent years， high yield pulping has attracted more and more attention because of its advantages， such as wide adaptability of raw material， high compact process， and low investment in equipment. In this paper， the high yield pulping method was firstly introduced， its characteristics in terms of pulping process and fiber slurry were discussed， and the development status of high yield pulp （HYP）was analyzed. Then， the application research progress of HYP was systematically discussed. To be specific， the application status of HYP in traditional paper and paperboard was summarized， and it was emphasized the high-value application of HYP in moulded pulp packaging material， higher value-added paper products， functional composites， and high-performance paper-based materials. Finally， the development of HYP by considering its process improvement and the demand of paper-based functional materials was forecasted.

[Abstract] [PDF]

Progress on Treatment Technique of Chemical Mechanical Pulp Wastewater

RAN Miao,DING Laibao,FANG Guigan,SHI Yingqiao,PAN Aixiang,TIAN Qingwen,WU Ting

2021,(7):33-39.DOI:10.11980/j.issn.0254-508X.2021.07.005

The source of chemical mechanical pulp wastewater and its pollution characteristics were introduced in this paper. It was summarized that the research status and progress of domestic and foreign chemical mechanical pulp wastewater treatment technology in recent years from the three aspects of pretreatment， biological treatment and advanced treatment technology. The advantages and disadvantages of existing treatment technologies and existing problems were analyzed. The development trend of chemical mechanical pulp wastewater treatment technology was prospected.

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Study on the Alkali Recovery Performance and Mixed Wastewater Treatment Technology of Effluent from Bamboo Chemical Mechanical Pulping Process

ZHANG Yu,SU Zhenhua,FAN Shujie,GONG Chen,NI Jianping,YANG Bin

2021,(7):40-46.DOI:10.11980/j.issn.0254-508X.2021.07.006

The physical and chemical characteristics of effluent from bamboo chemical mechanical pulping process were analyzed to evaluate its feasibility of alkali recovery， and the anaerobic-aerobic+Fenton deep oxidation process was used to treat its mixed wastewater （including white water and washing water of paper machine with CODCr concentration of 2950 mg/L） to study the discharge water quality in this study. The results showed that the rheological property of concentrated effluent from bamboo chemical mechanical pulping process was better than that of black liquor from bamboo chemical pulping process at the same concentration. The chlorine content of concentrated effluent （0.94%） was closed to that of bamboo chemical pulping black liquor. Both calorific value （high calorific value was 11.91 MJ/kg， low calorific value was 10.89 MJ/kg） and expansion volume （19.52 mL/g） were slightly lower than bamboo chemical pulping black liquor. There was a linear relationship between the solid concentration （Y） and Baume degree （X） in the concentrated effluent with the relationship equation of Y=1.5196X-1.693， indicating that alkali recovery technology could be used for its treatment. After the mixed wastewater was treated by anaerobic-aerobic+Fenton deep oxidation， the removal rate of CODCr was 97.3%. The qualities of the treated effluent could meet the demand of Discharge Standard of Pulp and Paper Industry Water Pollutants （GB 3544—2008）.

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Press Treatment of Caustic Green Mud from Alkali Recovery of Chemical Mechanical Pulp

HE Guanzhou

2021,(7):47-50.DOI:10.11980/j.issn.0254-508X.2021.07.007

The treatment methods of caustic green mud from alkali recovery of chemical mechanical pulp was introduced， and the different characteristics of caustic green mud from chemical mechanical pulp and alkaline pulp were discussed in this paper. The plate and frame filter press were used to instead of the traditional horizontal screw centrifuge to process causticizing green mud. The dryness of caustic green mud after treatment with plate and frame filter press could be increased 10%~13%， the residual alkali could be reduced 3%~5%， and recovery of pure solid alkali could be increased about 2 t/d. The problems like low dryness and viscosity of green mud were solved， providing conditions for the subsequent reuse of green mud.

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A Successful Updating Practice on BCTMP Pulping Production Line

JIAO Jian,LIU Yanshao,LI Gang,PAN Aixiang,DENG Yongjun,ZHANG Fengshan,FANG Guigan

2021,(7):51-55.DOI:10.11980/j.issn.0254-508X.2021.07.008

A poplar bleached chemi-thermo-mechanical （BCTMP） pulp line was updated， which strengthened the mechanical treatment of the prepreg section and the penetration and diffusion of liquid medicine. The updated line was operated stably with the refining energy consumption reduced by 21.42%， and the shive content reduced from 0.10%~0.18% to 0.02%~0.08%， physical strength of pulp improved accordingly. It provided an effective solution to solve the common problems of most domestic chemical mechanical pulp production lines due to the change of raw materials.

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Engineering Design for Chemical Mechanical Pulp

JIN Meng,XIA Qinggen,ZHANG Chengfeng,ZHANG Cheng

2021,(7):56-61.DOI:10.11980/j.issn.0254-508X.2021.07.009

With a new chemical mechanical pulp production line in a paper mill in south of China as an example， combining of the mainstream production process of chemical mechanical pulp and the practical engineering design experience， the main production processes and equipment characteristics of chemical mechanical pulp and a detailed description of its equipment layout design were introduced in this paper.

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Preparation of Nanocellulose from Corncob Residue Using Carboxyethylation and Alkali Pretreatment

CHEN Changming,CHEN Jinghuan,LIU Jingang

2021,40(7):62-69.DOI:10.11980/j.issn.0254-508X.2021.07.010

The residue after extracting xylose from corncob is rich in cellulose and lignin. In this study， corncob residue was pretreated by carboxyethylation and 1% NaOH solution， respectively， and then fibrillated into nanocellulose using mechanical grinding. Finally， nanocellulose films were formed by rod coating method. The chemical structure， component content， micro morphology， size distribution， water contact angle and thermal stability of the corncob residue， nanocellulose and their films were analyzed and characterized. The results showed that carboxyethylation pretreatment could increase the content of carboxyl group in corncob residue and remove part of lignin， while alkali pretreatment could remove most of lignin. After pretreatment， the size of raw materials decreased significantly and the accessibility increased. Compared with alkali pretreatment， the diameter and distribution of nanocellulose obtained using carboxyethylation pretreatment were smaller and more uniform. At the same time， the surface of these films was compact and their water contact angle was large. In addition， both pretreatment methods reduced the thermal stability of the final nanocellulose films.

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Effect of Lignin Content on the Thermal Stability of Cellulose Nanofiber

WANG Xuchong,ZHANG Sheng,YUAN Xiaojun,LU Lirong,ZHANG Rijing,XU Ziyue,SUN Wen,LUO Lianxin

2021,40(7):70-77.DOI:10.11980/j.issn.0254-508X.2021.07.011

The hot water， green liquor and bleach pretreatment were used to change the lignin content of bagasse and spruce cellulose nanofibers and explore the effect of residue lignin content on the thermal stability of cellulose nanofibers. The results indicated that the lignin content of SCB-HW and SP-HW was 16.1% and 8.9% higher than SCB-GL and SP-GL， 22.7% and 24.3% higher than SCB-B and SP-B， while hemicellulose the content was relatively low. The thermal stability of SCB-HW and SP-HW was 4.3% and 5.4% higher than that of SCB-B and SP-B， respectively. Conclusively， the different pretreatment changed the lignin and hemicellulose content of cellulose nanofibers and impacted the thermal stability of cellulose nanofibers.

[Abstract] [PDF]

Carboxymethylated Wood Fibers for Rolled Reconstituted Tobacco Sheet as a Reinforcing Phase

WEI Pei,GAO Song,LI Guanhui,FANG Zhiqiang,LIU Zhichang,SHU Hao,TONG Yuxing,LE Xi,WANG Ziwei,CHEN Yizhen,YAN Qunshan,PENG Rui,WAN Chao

2021,40(7):78-86.DOI:10.11980/j.issn.0254-508X.2021.07.012

The influence of etherification process parameters on fiber carboxyl content was studied by designing orthogonal experiments， and the effects of carboxyl group content on fiber morphology， crystalline structure， water retention capacity of wood fibers and its dispersibility in reconstituted tobacco were explored in this study. Finally， a comparison in reinforcement effect of original fibers and carboxymethylated fibers with different carboxyl group contents was carried out. The results showed that the order of these process factors affecting the fiber carboxyl group content was as follows： reagent dosage>fiber concentration>reaction time. The content of carboxyl group was proportional to reagent dosage and inversely proportional to fiber concentration with an optimum reaction time of 50 min. With the increase of carboxyl group content， the average width of carboxymethylated wood fibers increased， the length-weighted mean length increased first and then decreased， while the fine content decreased first and then increased. Besides， carboxymethylated wood fibers with higher carboxyl content groups showed a higher water retention value and could improve their dispersion uniformity in reconstituted tobacco sheet. Compared wit, h sample of original wood fibers， rolled reconstituted tobacco sheet with carboxymethylated fibers （carboxyl group content≥0.65 mmol/g） indicated a 35.8%~106.6% increase in tensile strength.

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Study on Improving the Performance of Superhydrophobic Filter Paper by ZnCl2 Pretreatment

CAO Xinyu,HUANG Guanhong,HU Zhijun,ZHANG Lu,CAO Yuchen

2021,40(7):87-92.DOI:10.11980/j.issn.0254-508X.2021.07.013

The superhydrophobic filter paper was prepared by ZnCl2 pretreatment and surface modification using filter paper as substrate. The effects of ZnCl2 pretreatment on hydrophobicity， stability and separation efficiency towards oil and water of hydrophobic filter paper were discussed. The results showed that the pretreatment could open the crystalline region of cellulose and expose more hydroxyl groups. The contact angle and sliding angle of filter paper were improved by ZnCl2 pretreatment with the optimum values of 154.8° and 6°， respectively. The contact angle of the pretreated superhydrophobic filter paper remained above 150° when the paper was in a neutral solution （pH value of 4~10）， indicating that ZnCl2 pretreatment improved the chemical stability and thermal stability of the filter paper. The hydrophobic filter paper maintained a separation efficiency of more than 95% after 30 times of separation towards thichloromethane.

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Application of Equal-standard Pollution Load Method in the Analysis of Wastewater Pollution Sources in the Whole Process of Chemical Pulping

CAI Hui,ZHU Wenyuan,WANG Shumei,WANG Liyong,DONG Yuanfeng

2021,40(7):93-98.DOI:10.11980/j.issn.0254-508X.2021.07.014

By determining the amount of wastewater， the types and concentrations of characteristic pollutants， and the state of existence in each process of the chemical pulping process， the equal-standard pollution load method was used to quantitatively analyze the standard pollution load and load ratio of each process and each characteristic pollutant. The results showed that the main pollutants in the preparation process were BOD， COD and suspended solids； the main pollutants in the cooking process were BOD and COD； the main pollutants in the washing， screening and purification process were BOD and COD； the main pollutants in the CEH bleaching process were dioxins； the main pollutants in the ECF bleaching process were BOD， COD and suspended solids； the main pollutants in the TCF bleaching process were BOD and COD； the main polluting processes were cooking and bleaching， and the cumulative equivalent pollution load ratio of these two processes reached more than 90%. The research results could provide a scientific and reliable basis for the whole process control of water pollution in chemical pulping in the paper industry.

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Application of Magnetic Coupling in Drum Pulper

HUANG Mengjie

2021,40(7):99-104.DOI:10.11980/j.issn.0254-508X.2021.07.015

It was introduced that the working principle of magnetic coupling and fluid coupling， and compared the technical characteristics of two couplings in this paper. The application of the magnetic coupling to the drum pulper was introduced from the aspects of selection， installation， debugging， maintenance and other aspects of the magnetic coupling， providing a new selection of transmission connection mode for drum pulper.

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Current Status and Prospects of the Japanese Paper Industry ——Overview of 2020 and Future Development Direction after COVID-19

2021,40(7):105-109.DOI:10.11980/j.issn.0254-508X.2021.07.016

[Abstract] [PDF]