Hemp - let the forest breathe

A
Ever since the United States Department of Agriculture (USDA) identified kenaf as a potential papermaking fiber material in the 1960s, a lot of experimental research has been done on the use of it as a substitute for wood as raw material for papermaking and a firm opinion has been obtained.
In 1987, Baker-field Californian, a Californian newspaper, printed 72,000 newspapers with 80% Kenaf CTM P pulp and 20% KP softwood pulp newsprint. The quality was fully qualified and the whiteness was very high (64 degrees). ), the use of less ink, hair loss is also less; test results, the use of softwood and hardwood material printing paper, writing paper, thin paper with kenaf to replace it is appropriate.
Thailand has built a Phoenix pulp and paper mill that annually produces 70,000 tons of kenaf pulp. China also uses kenaf for papermaking in Hunan's Minjiang, Henan Wuyi, Xinjiang's Miquan, Shandong Lucheng, Jining, and Chongqing's Pengshui. These paper mills and production lines have an annual production capacity of over 10,000 tons. Despite this, kenaf pulp is still small in size and production is limited. Why is this?
(1) The most suitable planting conditions for kenaf are: Average daily temperature 22-30°C, average nighttime temperature 18-23°C. The frost-free period is at least 150 days. The average relative humidity is 68-82%, and the rainfall is well distributed during the growth period. Flat land, deep drainage, good sand fertile soil is best. As far as the world is concerned, the suitable area for planting is limited.
(2) The planting of kenaf tends to use the methods of southern breeding in northern China to increase the yield but not to produce seeds. The economic value of the seeds and seeds of kenaf is also low. The income of the ramie stems alone is too single. In China, it is not as good as corn and other field crops. The income in Thailand is not as good as the income from cassava cultivation.
(3) Kenaf has a large amount of pith, is not easy to dry, and has large water content. It is more difficult to store than ordinary grass materials and is easily mildewed. After 25 days of cutting, Kenaf is placed in a room (about 17°C) for 7 days. The surface of the whole rod is long green and black with mildew. The separation of the bar skin and the blackening of the outer skin result in troubles for cutting and bleaching and affect the quality of the product.
Therefore, although some achievements have been made by kenaf instead of wood, it has been slow to develop and has not made significant progress.
B
Compared to kenaf, hemp is more economically viable for papermaking:
Shenyang City Jiantong New Company produced nearly 10,000 hectares of hemp in 1999. Hemp whole rods and kenaf rods were also placed indoors (17°C) for 7 days. Kenaf all rods became moldy and black, and the whole cane of marijuana had no mildew. The hectare yielded 30-70 kilograms of hemp seeds, which is superior to that of kenaf. Cannabis seeds were detected by the World Cannabis Center. The content of hazardous substances was THC 0.00027%, which meets the requirements of the international market (the international market requires THC <0.3%). Ma seeds export 1 kg l-l. For $5, this alone is equivalent to the income from corn. The cane produces 700-1100 kg of whole cane. The stalks were then sold to paper mills at a price of around US$45 per tonne, and farmers growing cannabis significantly increased their incomes. More importantly, hemp fiber is suitable for papermaking:
The average fiber length of hemp skin is 16mm, conifers only 3mm, and hemp core rod is 0.54mm, which is slightly lower than the length of hardwood fiber. Hemp all-pole is equivalent to long and short fibers and is suitable for papermaking.
The chemical composition of hemp is more suitable for papermaking: the chemical composition of hemp is 51.32% (coniferous wood is 50.86%), the pulp yield is high, the lignin content is 14.97%, and the coniferous wood is 27.85%. The lignin content is low and easy to cook. When bleached, the dioxin produced by the reaction of lignin and chlorine is low and the pollution is light. Hemp Polypentose was 18.29%, 11.12% higher than that of coniferous wood, 24.25% lower than hardwood, 25.56% wheat straw, and 22.46% reed. Polypentose was moderately apt to swell and beating. The ash content is 2.24%, which is far lower than that of wheat straw 6.04%, rice straw 15.5%, and low ash. According to analysis by the China Pulp and Paper Research Institute, the black liquor contains more silicon than grassy materials (such as wheat straw and alfalfa). ) Pulp black liquor contains a much lower amount of silicon, which, like coniferous pine, is suitable for alkaline recovery, which is conducive to the implementation of environmental protection projects and to discharge it to the standard.
Tongxin Company has planted Hebei Dabaipi varieties for three years. The actual yield per hectare of cannabis seed is 45kg, and the average yield per mu rod is 800kg. The economic benefit per mu is 100 yuan more than that of corn; the harvest of cannabis after it is put in the ground is reduced to 20% or less after one month, unlike black worms, which will produce moldy dark spots, which is beneficial to the production of bleached paper. In the past three years, the Shenyang Institute of Natural Fiber Research conducted cooking, bleaching, beating, and paper-making tests on hemp husks, core rods, and full rods (leaves and cores that were not separated). It was determined by the State Light Industry Bureau's paper quality supervision and testing station in Shenyang that the quality of the paper pulp produced by the hemp peel was better than that of softwood pulp; the core rod was similar to the hardwood pulp; the full bar was equivalent to the mixed pulp of the needle and the broadleaf. The strength of the paper proves that hemp is a promising papermaking raw material.
However, with hemp rods as raw materials, the production of coated paper, writing paper, typing paper and other cultural paper, the scale of pilot production, tons of paper profit was only about 250 yuan, obviously the economic benefits are too low, any link costs a slight increase or mismanagement It is likely that the mistakes of kenaf will be repeated. Only by using high technology to transform traditional industries and develop new ways can we get rid of the plight of kenaf pulping.
The paper mills are heavily polluted. In the past, cooking effluent (alkali method called black liquor and acid method called red liquor) was considered the culprit. Recent studies and actual measurements have shown that the harmfulness of bleaching wastewater is much greater than that of cooking black liquor (red liquor), and the toxicity is great. At the end of the 1980s, Sweden, Finland, Norway, the United States, Canada and other developed countries in the paper industry detected “triple” substances with carcinogenicity, mutagenicity, and teratogenicity from bleached wastewater, sludge, and bleached paper products. , It can inhibit the immune function, affect the secretion of hormones, make the male female, affect children's growth and development, and increase the tendency of multiple brain neuropathy, intracranial hemorrhage, increase the risk of diabetes. It contains Dioxines, of which 2,3,7,8-tetrachlorodiphenyl dioxin (TCDD) is the most toxic and is referred to as "the most toxic poison on the earth." More than 1000 times of potassium cyanide and 500 times of brucine.
In the period from the beginning of 1999, Belgium and other countries had successive incidents of dioxin-contaminated animal products and dairy products containing high concentrations of dioxins, which shocked the world and caused consumers to some degree of panic.
Dioxins are highly toxic, have a half-life of 7 years, and have a residual time of 10 years in the soil. They are “sustainable bioaccumulative” drugs. They accumulate in the environment, aquatic organisms, and human bodies. As time bombs do, they may trigger cancers. . People are panicking and strongly opposed to the use of chlorine-containing bleaching agents. Some newspapers use the theme “Why should the paper be so white?” and accused paper mills of producing dioxin to pollute the environment and endanger aquatic life and human health. The current incidence of cancer, cardiovascular and cerebrovascular diseases, diabetes, renal insufficiency, children's stunting, malformation, etc. is high. It is difficult to understand the mechanism of carcinogenesis and pathogenicity. Chlorine bleaching in paper mills has become the “chronic point”. The focus of public opinion. In addition, paper and people's lives are very close, especially packaged foods and beverages, such as the U.S. detection of 0.04 ppt of dioxin from carton-packed milk, thought to be dissolved from bleached pulp, which exceeds safety. Standards (US EPA regulated dioxin levels below 0.000013 ppt in water purification standards). Filtration paper, filter blood, water, beverages, alcohol, oil, and other bleached pulp products such as filter paper and cardboard are very strict and stricter. This requires bleaching without chlorine to produce dioxins-free pulp, paper, and paperboard.
92% of the world's papermaking raw materials are wood. Most of them are kraft pulps. The kraft pulps are deep and brown in color. The whiteness of this color paste is only about 13%. Chlorine bleaching is not easy, and chlorine-free bleaching is even more difficult. .
C
TCF Pulp and Paper is a green product that has gained popularity around the world.
According to Proceedings of the 6th Academic Annual Meeting of the Beijing Papermaking Association in February 1999, Prof. Yang Zhixiong, Professor of Vice President of the China Papermaking Society and Chairman of the Beijing Papermaking Society (Prospecting Sustainable Development of the Paper Industry) ) Introduction, no elemental chlorine and no chlorine bleaching, "The paper produced has been generally welcomed in Europe."
According to the paper published by the China Paper Society, “Paper and Paper”, “Although the use of 100% C1O2 to replace C1 2 bleaching has reduced the amount of bleached wastewater AOX (an indicator of dioxin content that can be adsorbed by organic halides) to very low levels. Lower, however, the world paper consumer market tends to need pulp that is not bleached by any chlorine-containing bleaching agents, especially in large importers of pulp in Germany, Switzerland, Austria, and the Netherlands. In the European market, particularly Germany, Switzerland, Austria and the Netherlands now require the import of completely fluorine-free pulp (TCF pulp).
According to the “Paper Digest”, Japan will renovate paper mills using chlorine pulping. Since the use of chlorine-containing compounds will generate dioxins and other harmful substances, the Japan Paper Industry Corporation plans to have 13 households under its jurisdiction by 2005. In pulp and paper mills, the use of chlorine-containing compounds was stopped. With the increase of consumer environmental awareness, the company hopes to take a step forward in the long-term demand for non-chlorine paper products.
According to “The Chem Engineer”, “The great challenges of the early 1990s forced the paper industry to develop a chlorine-free bleaching process. This development has greatly changed the chemical pulp mill, has no environmental impact, and is economical. By the year 2003, chlorine-free bleaching will Occupies 75% of the world's bleached pulp."
With the gradual enhancement of people's environmental awareness, all non-fluorinated bleached pulp will be favored and the market prospect is very broad.
D
86% of China's pulp production is non-wood fiber. Non-wood raw materials for papermaking, low raw material lignin content, easy cooking and non-fluorinated bleaching, non-toxic dioxin in bleached wastewater and paper products, and marijuana in China (especially north of latitude 30° north) contain harmful substances TH C is 0.00027% (International Standard requires TH C <0.3%) and it can be grown and used for industrial processing. China has a long history and experience in planting hemp, widely used in papermaking and cannabis bleaching. The paper produced has been welcomed by customers from Germany and Japan. We believe that in the international market, we should not use our small arms to twist other people's thighs and go to the others to use the non-wood fiber non-chlorine paper to occupy the world market, so that China's paper industry has a place in the international market.
E
According to the fifth national survey of forest resources, China currently has a forest area of ​​158.9 million hectares (per capita forest area is 1/6 of the world's average), and forest reserves are 11.27 billion cubic meters (one per capita forest reserves is the world's average. /8). After years of efforts across the country, the forest coverage rate has increased from 12.7% to 16.55%, which is only 61.3% of the world average. China is a Shaolin country with insufficient total forest volume and uneven distribution. The area of ​​mature and over-mature forests accounts for 14% and the volume of reserves accounts for 38%. Natural forests are numerous, and most of them are not available for harvesting in ecologically important areas. Compared with the range of forest cutting quotas approved by the State Council, the average national forest consumption exceeding the limit amounted to more than 86 million cubic meters. Due to the deforestation of natural forests, serious floods occurred in both the south and the north in 1998. The State Council issued an order to require the logging of natural forests to be prohibited in the next few years. It is therefore necessary to import logs and wood chips.
At present, the annual demand for commodity wood is about 100 million cubic meters, and the actual supply is 50 million cubic meters, and the gap is half. From 1995 to 1998, the average annual import of wood (equivalent to logs) was 45.8 million cubic meters. In 1998 alone, foreign exchange payments for timber imports amounted to US$6.34 billion.
Therefore, the country is urged to provide more wood and imported wood (including wood chips) to the paper industry, and the proportion of wood used in papermaking materials is very limited, which is not in line with national conditions. In order to increase the papermaking ratio of wood raw materials, it must be combined with forestry paper. The papermaking industry must have its own wood raw material base to ensure its survival and development.
However, today's papermaking industry has a wood raw material base, and the cultivation period is 6 years for China's southern hardwood species such as Acacia and Acacia, and coniferous species such as Caribbean pine and Masson pine for 12 years. It takes 15 years for broad-leaved trees such as Sanyang, and for conifers such as Larix gmelini, Larix olgensis, and Japanese larch for 25 years. The triploid poplar was cultivated in the middle and lower reaches of the Yellow River and the cultivation period was 8 years. It is about 5 years for the fast-growing forest cultivation cycle. Shorter growth period will affect the strength of the produced paper. The consumption of paper products and paper production in China have increased year by year. It is impossible to stop growing trees and grow large numbers of young trees, which poses a great threat to the cultivation of reserve resources. So, make