The Clean Separation Of Components From Bamboo With Oxygen-weak Base Salts And The Properties In Papermaking Of Pulp Based On Biomass Refining With Acetic Acid

The optimized integration with the biomass refining industry is one of the effective ways in upgrading and sustainable developing for the pulp and paper industry,and it is also an important support for an powerful biomass refining industry.Based on the above background,this paper has carried out two aspects of research.First,a synergistic treatment of steam explosion pretreatment combined with oxygen-weak alkali salt cooking was proposed for the rigid structure of moso bamboo,aiming to cleanly and efficiently separate the components of bamboo to achieve the basic requirement for the preparation of levulinic acid,providing a scientific basis for a new clean separation process upon fiber raw materials.The second was to analyze the fiber characteristics of five kinds of acetic acid biomass-refined pulp by existing detection methods.And evaluate the feasibility of its use in papermaking,providing a new way and scientific basis for the replacement of papermaking raw materials.The study also pointed out the limitation factors to the paper properties,and clarified the ideas for the acetic acid biomass refining enterprises to further optimize the process.In the first part of the research,this paper pretreated moso bamboo with steam explosion.The results showed that when the steam explosion pretreatment condition was 2.5 MPa?10min,60.94%of hemicellulose dissolved,the honeycomb structure appeared on the fiber surface,and the fiber specific surface area increased from 0.8061 m²/g to 1.9494 m²/g.In the synergistic treatment process of steam explosion combined with oxygen-weak alkali salt cooking,the best combination condition was:steam explosion pretreatment conditions was 2.5 MPa?10 min,and oxygen-weak alkali salt cooking conditions was 20%Na₂CO₃,The oxygen pressure 2 MPa,the maximum temperature 180?,and the time 1.5 h.Under the optimal combination conditions,more furrows appeared on the fiber surface,the specific surface area of the fiber increased to 1.33 times of the raw fiber,and a cellulose-rich component with high cellulose content?72.88%?and low lignin content?7.87%?was obtained,which met the preliminary requirement for preparing levulinic acid?the lignin content is required to be less than 8%.?.In addition,under the optimal combination conditions,the BOD₅,COD and BOD₅/COD values of the cooking waste liquid were 17265 mg/L,57537mg/L and 0.3,respectively,indicating the cleanliness of the oxygen-weak alkali salt cooking process.In the second part of the research,this paper took five acetic acid-based biomass refining pulps produced by Y company?reed pulp,bamboo pulp,eucalyptus pulp,corn straw pulp,bagasse pulp?as the research objects,and determined their fiber characteristics.It was found that compared with the cellulose?81.27%?,hemicellulose?16.62%?and lignin?2.32%?in the hardwood KP pulp,the cellulose content?73.60-87.83%?in the five pulps was similar to that of sulfate pulp,while the lignin content?4.63-7.91%?was higher and the hemicellulose content?5.24-10.82%?was lower,which is not good for paper strength.XPS results showed that the lignin content on the surface?20.83-25.35%?of the pulp was higher than the overall lignin content.In addition,the five kinds of pulp fibers were deeply processed during the biomass refining.There were many breakage points on the fiber surface,such as fractures,holes,etc.,which made the fiber strength 8.45-37.12%lower than that of sulfate pulp.Based on the above performance indicators,the performance of five pulps was compared.It was found that the performance of reed pulp was the best,the bamboo pulp,eucalyptus pulp and corn straw pulp were average,and the bagasse pulp was poor.The paper properties of the five pulps were comprehensively compared from the six aspects including tensile strength,burst strength,tearing,folding strength,ring crush strength and stiffness,and the five pulps were ranked?from good to bad?:reed pulp,bamboo pulp,eucalyptus pulp,corn straw pulp,bagasse pulp.Among them,the tensile,ring crush strength and stiffness of reed pulp and bamboo pulp were 63.47 and 53.58 N·m/g,7.22 and 7.78N·m/g,0.82 and 0.92 m N·m²/g,respectively,which were better than that of waste paper pulp.Therefore,reed pulp and bamboo pulp can replace waste paper pulp for the production of packaging paper such as corrugated base paper.The bagasse pulp has a poor paper performance,but it can also meet the basic requirement of making corrugated base paper and other packaging paper by mixing it with long fiber pulp.By studying the effect of adding xylan on the performance of paper from eucalyptus pulp,it was found that the addition of 2-5%xylan into the pulp,the tensile strength,burst strength,tearing,and folding strength of eucalyptus pulp increased 16.17-20.42%,46.61-52.12%,12.22-14.48%,166.67-111.11%,respectively.The paper strength has been significantly improved,verifying that hemicellulose has a large contribution to the paper strength of acetic acid biorefinery pulp.Accordingly,it was recommended to Company Y that the biomass refining process conditions could be adjusted appropriately to have 2-5%hemicellulose content retained in the eucalyptus pulp,which may greatly improve the paper performance of the eucalyptus pulp.