Characteristics and Countermeasures of the hottest

The characteristics and Countermeasures of the national conditions of papermaking (Part 2)

once the hybrid triploid Populus tomentosa came into being, it was provided with its seedlings out of the nursery in one year (originally 2 years), the ecological benefits of three-year forest (originally 5-6 years), and the emergency timber of five-year rotation (originally more than 10 years), which changed people's understanding of the long forestry cycle and late effect, and convinced that Populus tomentosa technology was a good way to speed up the growth of Populus tomentosa, Stimulate people's enthusiasm for planting triploid Populus tomentosa

according to statistics, 250million new varieties have been promoted nationwide, with an annual increase of more than 1billion yuan compared with the old Populus tomentosa, which has promoted the rise of a new industry combining triploid Populus tomentosa cultivation industry with processing industry (papermaking and board making) in the Huang Huai Hai region, with significant ecological, social and economic benefits. Leaders of the State Council and the Ministry of forestry have visited the base for many times and believed that triploid Mao 2. This hydraulic universal experimental machine focuses hydraulic devices with seven functions on one proportional valve assembly (including electro-hydraulic proportional valve, electromagnetic steering valve, and manual conditioning valve). The breeding of new poplar varieties "will bring a revolutionary change to China's forestry industry" (Yang Yongzhe 1998), "is the pride of the country" (Li Yucai 1997). Vice Premier Wen Jiabao of the State Council (1998) and Premier Zhu Rongji (2001) gave special instructions to triploid Populus tomentosa

under the cordial care of the State Planning Commission, the economic and Trade Commission, the State Administration of forestry and other leaders, the project establishment and papermaking of Triploid Populus tomentosa pulp forest have been greatly promoted. At present, according to the spirit of the instructions of Vice Premier Wen Jiabao, the State Forestry Administration is building 770000 hectares of the Yellow River Corridor Project dominated by triploid Populus tomentosa along the banks of the Yellow River 2000km from Pianguan, Shanxi Province to Dongying, Shandong Province; Some far sighted entrepreneurs have also targeted the afforestation and papermaking of Triploid Populus tomentosa, making it a new situation for China's afforestation and papermaking. They have entered a new stage of poplar paper industry (stage 4) operated by the market and operated by enterprises, such as Yanzhou Taiyang, Gaotang Quanlin, Dongying Huatai, Heze Chengwu, Shanxi Xiangfen, Henan Wuzhi, Jiaozuo, Mengzhou and other paper industries, Both have started the construction of Triploid Populus tomentosa pulp raw material forest and the technological transformation of wood pulp. It is expected that the pulp forest built by the above-mentioned paper-making enterprises will reach 3million Mu within five years, enough to supply 2million tons of machine pulp raw materials per year. The situation is very gratifying

according to estimates from economic circles, within 10 years, China will spend nearly 100 billion yuan a year to import pulp, which will be reversed

the breeding of an agricultural variety (such as yuanlongping rice) can feed nearly 100 million more people; The advent of a new forestry variety will enable China to achieve self-reliance in the production of papermaking raw materials. Improved varieties, especially high-tech improved varieties, have always been used as a lever to drive the agricultural and forestry industry forward, which will bring hope to the Yellow River paper industry

6. The quantity has increased, and how about the quality

from the 10-year growth record of Triploid Populus tomentosa afforestation, the suitable growth areas on both sides of the Yellow River can produce 10 cubic meters of wood per mu in a rotation period (5 years) based on the minimum output of 2 cubic meters per mu per year, which has been recognized by everyone. This is twice the international poplar growth level (Italy, Finland, black poplar 1 cubic meter per mu per year), not to mention we are Populus tomentosa

but people in the paper industry ask: how about the quality of papermaking when the quantity increases? Because how fast the world is often may not be good province, good province is often bad waste. Is there any experiment on paper quality with triploid paper? Now the answers are as follows:

(1) from the perspective of the international practice of papermaking raw materials of broad-leaved pulp trees, the United States, Canada, Europe and other countries all use Aspen of poplar for papermaking. We also use Aspen, which belongs to the same family, the same genus, the same school of tree species, with the same caliber. In many ways, China's Populus tomentosa is stronger than their Aspen

(2) from the perspective of wood chemical components and fiber morphology, 5-year-old triploid Populus tomentosa has advantages over common Populus tomentosa and black poplar. It can be seen from table 1 that the triploid Populus tomentosa has high fiber content and low lignin and pentose content, which makes the triploid Populus tomentosa paper-making yield high (mechanical pulp%, chemical pulp 48%), easy to soften and boil, and good beating and papermaking strength

chemical composition of poplar wood such as triploid Populus tomentosa Table 1 variety benzene alcohol extract lignin cellulose pentose

triploid Populus tomentosa 1.67 17.7 83.6 20.18

Populus tomentosa 2.15 19.8 76.2 -

European aspen - 17.1 42.24 22.61

fast business Poplar - 24.94 49.01 23.23

(3) from the perspective of fiber morphology, triploid Populus tomentosa is superior to ordinary Populus tomentosa, black poplar and Beijing 605 poplar. Fiber length is an index to measure the advantages and disadvantages of papermaking raw material trees. The average fiber length of Triploid Populus tomentosa is 1.28mm, which is rare among five-year-old poplar species. Moreover, their machines are mainly composed of driving system, transmission system, control system, high and low temperature experimental devices, with uniform distribution, large length width ratio and small wall cavity ratio. They belong to thin-walled cells, and have good fiber morphology, which is important for papermaking yield The paper strength and the interweaving force and softness of beating and papermaking are very beneficial (see Table 2)

(4) in terms of beating energy consumption and pulp whiteness, triploid Populus tomentosa has moderate wood density (0.4), smooth and straight fiber lines and no black heartwood, which is superior to black poplar, which often has black heartwood. At the same beating degree, such as 70osb, the grinding energy consumption of Triploid Populus tomentosa is 1240kwhod/mt, which is about 14% lower than that of Populus Tomentosa (1420) and 21% lower than that of black poplar (1580), so it is a low-energy tree species. Triploid Populus tomentosa wood whiteness (53%), no black heart, low bleaching drug consumption, little pollution, in APMP process, 30% hydrogen peroxide dosage, its pulp whiteness is up to 80%; When the dosage of hydrogen peroxide in black poplar is 5%, the whiteness of its pulp can reach 75%. It can be seen that the drug consumption of triploid white poplar is 40% less than that of black poplar

(5) from the quality of beating and papermaking, the tensile strength and tear strength of paper are important indicators of paper performance. Generally speaking, the stronger the bonding ability between pulp fibers, the better the tensile strength; The tear strength is not only affected by the fiber bonding strength, but also related to the fiber length. In APMP pulping, under the same beating degree (such as 70osr), the tensile index of Triploid Populus tomentosa is 42N · m/g, 37.5 for Populus tomentosa and 30.0 for Populus nigra, indicating that the paper strength of Triploid Populus tomentosa is 14% higher than that of ordinary Populus tomentosa and 42% higher than that of Populus nigra. In terms of tear resistance index, under 70osr, the tensile index of Triploid Populus tomentosa is 4.8n · m/g, that of common Populus tomentosa is 4.3, and that of black poplar is 4.0, which is also far better than that of common Populus tomentosa by 11.6% and 20% respectively. Therefore, in terms of paper tensile strength and tear index, triploid Populus tomentosa is better than ordinary Populus tomentosa, better than ordinary Populus tomentosa, and better than black poplar