Bamboo fibercontent is high.fiber shape is long,mechanical proterties and plasticity are good.Bamboo as good substitute for wood raw materials.It can be meet the pulp requirements of medium and high grape paper.Research show that,bamboo chemical composition and fiber properties have good pulping properties.bamboo pulp properties second only to coniferous wood pulp,better than broadleaf wood pulp and grass pulp.It’s great significance to develop bamboo pulping and paper making industry,in order to remit the shortage of wood pulp.
Bamboo growing very fast. Orinary 3-4 years can be grow up.And bamboo forest have strong carbon effect,make the bamboo economic benefits,environmental benefits and social benefits are increaseingly prominent. Currenty China bamboo pulp production technology and machine have gradually matured,plane,grinding and other host equipment has realized domestic production.Large and medium-sized bamboo paper production lines have been industrialozed in Guizhou,Sichuan and other place.
Bamboo pulp paper chemical character
As for biomass materials, bamboo have cellulose,hemicellelose,lignin 3 chemical compenent, In addition have a small of pectin,starch,polysaccharide and wax.Through analyzing the chemical composition and characteristics, can be understand bamboo as paper making materials merits and demerits.
1.Bamboo have higher cellulose
Superior finished paper has higher requirements on pulp raw materials. Require collelose content more higher more better. Lignin,polysaccharide and other extracts more lower more better.
2.Bamboo fiber is long, long diamter is laege
The average length of bamboo fiber is 1.49~2.28mm,the average diameter is 12.24~17.32 μm, long diameter ratio as 122~165. The average fiber wall thickness 3.90~5.25 μm. The wall to cavity is 4.20~7.50. They are belong thick-walled fibers with large length and diameter.Paper pulp materials mainly on cellulose of biomass materials for paper making require high cellulose content and low lignin content, which can not only improve pulp yield. But also reduce ash and extract. Bamboo materials have long firber,long diameter etc characteristic.Made bamboo pulp into paper after the unit area of fiber interweaving more times,paper strength is better. Therefore,bamboo pulp performance is close to wood.stronger than straw.Wheat straw.bagasse and other gramineous plants.
3.Bamboo fiber with high fiber strength
Bamboo cellulose not only has renewable,degradable,good biocompatibility,strong hydrophilicity,excellent mechanical properties and heat resistance etc charactistics.Some scholars conducted tensile test on 12 kinds of bamboo fibers and found that their elastic modulus and tensile strength were both higher than thoseof wood fibers from artificial fast-growing forests.The results show that the tensile modulus and strength of moso bamboo fibers were higher than those of the other three fibers.
4.Bamboo ash and extract content is higher
Compared with wood, the content of ash(about 1.0%) and 1% NAOH extract(about 30.0%) in bamboo higher. Which will produce more impurtities in the pulpling process,which is not conducive to the sewage and wastewater treatment of pulp and paper industry. And will increase machine investment cost.
Bamboo pulp papermaking technology
Since bamboo successfully realized industrial development and utilization,there have been many new technology,new processes,new products of bamboo processing. Thus make the bamboo improving the utilization value.The development of mechanized pulping technology in China has broken through the traditional manual modeand is tranforming to industrialization and industrial production mode. At present. Popular bamboo pulp production technology includes mechanical method.chemical method and chemical mechanical method. China bamboo pulp was mainly processed by chemical method,about have 70%. Chemical mechanical method is less, less than 30%. The production of bamboo pulp by mechanical method is limited to the experimental stage and no large-scale industrialization has reported.
1.Mechanical pulping way
Mechanical pulping is the mechanical grinding of bamboo into fiber,without adding chemical agents, this way advantages of low pollution, high pulp yield,simple process and so on. Under the situation of pollution control and shortage of wood pulp has been paid more and more attention.
Although mechanical pulping method has the advantage of high pulping yeild and low pollution.it is widely used in the pulp and paper industry of coniferous wood such as picea,but due to the high content of lignin, ash and 1% Naoh extract in the chemical composition of bamboo,the pulp quality is poor, and it is difficult to meet the quality requirements of commercical paper.The industrial application is rarely seen,mostly in the stafe of scientific research and technical exploration.
2.Chemical pulp process
Chemical pulpping is bamboo pulp made by sulfate or sulfite process.Bamboo pulp was prepared by screening,washing,dehydration,cooking,causticization,filtration,countercurrent washing,closed screening,oxygen delignfication,bleaching and other process.The cheminal pulping processes can protect the fiber and improve the pulp yield. Obtain the pulp with good quality,clean and soft,easy to bleach,can be used to produce high-grade writing paper and printing paper.
Due to the removal of a large amount of lignin,ash and various extracts in the process of chemical pulping, the pulping yield of bamboo is low,generally 45%-55%.
3. Chemical mechanical pulping process
Chemical machanical pulping based on bamboo pulp for raw materials,which combine chemical pulping process and mechanical pulping process some characteristic as bamboo raw material way. Chemical pulping process include semi-chemical method,chemical machanical method and chemical thermal grinding machine method.
For bamboo pulping and paper making,, the pulping yield of chemical mechanical pulping,generally arrived to 72%-75%.Chemical mechanical pulping method this way produce pulping quality higher than mechanical pulping method. Can be satifies normal products production requirement. At the same time,the cost of alkali recovery and sewage treatment is also between chemical pulping and mechanical pulping.
Bamboo pulp paper equipment
The molding section equipment of bamboo pulp and papermaking production line is basically the same as that of wood pulp production line. The biggest difference of bamboo pulp and papermaking equipment lies in the section for preparing materials such as slicing,washing and cooking.
Because bamboo has a hollow structure,slicing equipment is different from wood. Commonly used bamboo slicing equipment mainly includes roller-type bamboo cutting machine,disk-type bamboo cutting machine and drum chipper. Roller type bamboo cutter and disk type bamboo cutter have higher working efficiency, but the quality of bamboo chips processed(bamboo shape) is not as good as that of drum type chipper. Users can be choose the appropriate slicing equipment according to the use of bamboo pulp and production cost. For small and medium-sized bamboo pulp mills(Capacity<10 ton).Domestic bamboo slicing equipment can meet the needs of production; For large bamboo pulp factory(Capacity≥10tons), Can be choose international advanced large slicing equipment can be used.
Bamboo washing equipment is used to remove impurities, and a variety of patented products have been reported in China. Generally,vacuum pulp washing machine,pressure pulp washing machine and belt type washing machine used. Medium and large enterprises can use new two-roll replacement pressing pulp washing machine or strong dehydration pulp washing machine.
Bamboo slice cooking equipment is used for bamboo slice softening and chemical separation. Small and medium-sized enterprises use vertical digester or horizontal tube continuous digester. Large enterprises can use Camille continuous digester with diffusion washing to improce production efficiency,pulp yield will be improved correspondingly,but it will increase one-time investment cost.
The potential and development direction of bamboo pulp paper in China
1.Bamboo pulp paper has great potential
According to investigation of bamboo resources in China and analysis of the applicability of bamboo itself in papermaking,strongly support develop bamboo pulping industry. Not only can remit the Chinese paper industry wood material shortage.It is also an effective way to change the raw material structure of paper industry,can reduce the dependence on imported wood chips.Some famous scholars have analyzed that the production cost per unit mass of bamboo pulp is about 30% lower than that of pine,spruce,eucalyptus,etc., and the quality of bamboo pulp similar wood pulp.
2. Forest paper integration is an important development direction
Due to the advantages of rapid growth and reproduction of bamboo, strengthening the cultivation of special bamboo forest and establishing bamboo pulp production base integrating forest and paper will become a direction for the sustainable development of China’s pulp and paper industry, reducing the dependence on wood chips and pulp imports, and developing national industry.
3.Tufted bamboo pulping has great development potential
In the current bamboo processing industry, more than 90% of bamboo (nanbamboo) as raw materials, mainly used in the production of household goods and structural materials products. And bamboo pulp paper is basically to bamboo (nanbamboo), bamboo as the main raw materials, forming a raw material competition situation, is not conducive to the sustainable development of the industry. Bamboo pulp and paper industry on the basis of the existing raw materials bamboo, should vigorously develop a variety of bamboo raw materials utilization, make full use of the low price of bamboo, bamboo, bamboo, bamboo bamboo pulp and paper, improve the vitality of market competition.