The most popular technology is to remove the hat o

2022-07-30
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Take off the "hat" of the major polluter to correct the name of the paper industry

release date: Source: China paper industry number of Views: 12246 copyright and disclaimer

core tips: for different processes, R & D has broken through 10 key technologies and 11 supporting technologies, formed 5 sets of science and technology innovation integrated technologies, and realized the clean production of pulp and paper and the whole process control of water pollution -

for different processes, The opacity of R & D principle has broken through 10 key technologies and 11 supporting technologies, formed 5 sets of scientific and technological innovation integrated technologies, and realized the clean production of pulp and paper and the whole process control of water pollution --

"now I can confidently say that green papermaking has been realized in the hands of our generation!" Chenkefu, academician of the Chinese Academy of engineering and professor of South China University of technology, said happily. Last year, when he and many experts visited Shandong Sun Paper Co., Ltd., an enterprise applying technological achievements, they were pleasantly surprised to find that the water quality at the outlet after wastewater treatment is clear and reeds are overgrown. It has become a famous local scenic spot, and many new people take wedding photos here

in view of the major problems of water pollution in the paper industry, in the past 10 years, Chen Kefu led his team to develop and break through 10 key technologies and 11 supporting technologies for different processes, and formed five sets of integrated technologies for scientific and technological innovation, realizing the clean production of pulp and paper and the whole process control of water pollution. Through the joint efforts of the whole industry, the paper industry has removed the hat of a major polluter and established a new image of China's paper industry

the state has issued four consecutive documents to regulate the paper industry

papermaking is an important basic raw material industry in China, with an output of nearly 100million tons in 2011, ranking first in the world. However, the problem of water environment pollution has become increasingly prominent. The data show that the total discharge of wastewater from the paper industry in 2011 reached 3.83 billion tons, accounting for about 1/5 of the total discharge of industrial wastewater; The total discharge of chemical oxygen demand (COD) reached 742000 tons, accounting for about 1/4 of the total industrial COD discharge. It is known as the "big polluter" by the society

"in that year, the state issued documents for four consecutive times, clearly proposing that the paper industry, a key pollutant discharge industry, should be specially regulated to strictly control the discharge of wastewater and cod. Solving the water pollution in the paper industry is an urgent major scientific and technological problem." Chen Kefu recalled

in 1971, chenkefu began to teach at Tianjin Institute of light industry and began to study pulp and paper, under the guidance of Professor longyanquan, a Chinese paper expert. "Mr. long often says that when we can solve the two problems of paper pollution and backward equipment, we can make real progress." He has always remembered this sentence

In 1994, a "water pollution incident in the Huaihe River Basin" shocked China and the rest of the world. The discharge of untreated wastewater from papermaking enterprises was an important reason for this. "4. The water discharged from the test piece is black." Hearing someone describe the situation in the polluted area, he was very sad. "My primary goal in my life is to find a way to solve the pollution problem in the paper industry."

2011, he led the project team to cooperate with two large paper-making enterprises in Shandong to establish an industry university research innovation team

"our scientific research philosophy is to make full use of resources as much as possible." Chenkefu said, "first, the technology developed must fully cover the papermaking industry; second, the traditional end-to-end treatment mode of wastewater in the papermaking industry must be changed, and a new mode of water pollution control in the whole process combining cleaner production and end-to-end treatment should be proposed to minimize the amount of wastewater. The ultimate goal is to make the water pollution discharge index of the papermaking industry better than the standards of the European Union and the United States, and the technical level of water pollution control should reach the international leading level."

technology has created many international firsts.

"the implementation and application of a new technology is an extremely complex process and will encounter many unforeseen problems." Chenkefu sighed

aiming at the problems of high COD concentration, heavy pollution load and difficulty in reaching the standard by conventional treatment methods, the team creatively applied the mechanical steam recompression evaporation technology to the pre evaporation of chemical mechanical pulping wastewater, combined with the multi effect evaporator to further concentrate and then send it to the alkali recovery system for combustion treatment, so as to realize the resource utilization of water pollutants

how to realize the continuous separation of cellulose, hemicellulose and lignin in chemical pulping is an international problem. In the laboratory, hemicellulose can be separated with low acid, but in the factory, this method is not effective, because low acid separation will affect the subsequent process. When the team was at a loss, they were inspired by the Cantonese "soup making"

"for example, if Cordyceps sinensis is boiled continuously for 20 to 30 minutes at a high temperature of 100 ℃, the beneficial components can be separated. Can hemicellulose be separated in this way?" The team tried to boil wood with hot water. After continuous attempts, they found that hemicellulose could be successfully separated by cooking wood chips at a high temperature of 170 ℃

the high temperature environment of 170 ℃ on the production line has created new challenges. To this end, the team innovated and developed continuous hydrolysis cooking technology and collaborative deep delignification technology, successively separated and extracted hemicellulose and lignin in a continuous state, and finally left cellulose, successfully realizing the full utilization of fiber raw materials. This is the first time in the world

waste paper becomes the most critical deinking process for new paper. The traditional alkaline deinking technology is the main link that leads to serious pollution load. The team innovated and developed near neutral deinking technology and papermaking wastewater cascade recycling technology, realizing the reuse rate of waste paper pulping water greater than 95% and papermaking water greater than 90%, saving water consumption and reducing wastewater discharge

but how to realize near neutral deinking in large modern alkaline waste paper pulping system? "This is a major difficulty we face in developing this technology." Chenkefu said that the output of the waste paper pulp and paper production line of the cooperative enterprise is very large, and it operates 24 hours a day. First of all, the technology should be tested on the production line. Due to the gap between the research and development of the laboratory and the actual production, the experimental scheme needs to be constantly adjusted. Through continuous cooperation with sharp electronics R & D (Nanjing) Co., Ltd., the technology application was finally realized

but technical problems come one after another. At the stage of pulp and paper wastewater discharge at the terminal, the team found that the existing conventional sludge dewatering treatment and equipment in the factory could not be used to achieve the dryness of resource utilization. "It can not be sent out for landfill treatment, which is prone to pollution transfer and secondary pollution. Therefore, if this problem is not solved, it will not be able to realize the resource utilization of sludge, which will seriously affect the promotion and application of this technology in production enterprises." After on-site investigation, technical exchange and several months of hard work, the team developed the electro osmotic dewatering technology for paper-making advanced treatment sludge, which increased the sludge dryness from 30% to more than 45%, solved the problem of sludge dewatering and paved the way for the application of this technology

sharpen a sword in ten years. The team has broken through 10 key technologies and 11 supporting technologies, formed 5 sets of integrated technologies for scientific and technological innovation, and created many international firsts

the discharge of wastewater has been lower than that of several key industries.

"the enterprises that adopt our technology not only reduce the wastewater treatment cost, but also the wastewater and COD discharge indicators per unit output are far better than the EU standards, and the clean production technology has reached the international leading level." Chenkefu said, "especially the COD emission per ton of products, through many third-party evaluations, we have achieved 1/10 of the EU standard."

now, the clean production of pulp and paper and the whole process control technology of water pollution developed by the project have all been selected into the HJ feasible technology guide for pollution prevention and control of pulp and paper industry issued by the Ministry of ecological environment, which has been promoted nationwide as an advanced technology recommended by the industry. Relevant technologies have been applied in the pulp and paper production lines and terminal wastewater treatment of 10 large and medium-sized paper-making enterprises such as Shandong Sun Paper Co., Ltd. and Shandong Huatai Paper Co., Ltd., and have been extended to pulp and paper-making enterprises in Guangdong, Guangxi, Henan, Hebei and other places

the data shows that, driven by the project, the total discharge of wastewater and COD in China's paper industry has decreased by 38.2% and 55% compared with 2011. The discharge of wastewater and cod has been lower than that of many key industries, removing the hat of a large polluter

"people think that trees must be cut down to make paper. In fact, it is not at all." Chenkefu could not help but "correct the name" of the paper industry. He said that the original intention of such public service advertisements as "use less paper and cut less trees" is good, but there are still misunderstandings about the paper industry. In fact, made in China, it is widely used in industrial and mining enterprises, colleges and universities and scientific research institutions. Paper raw materials do not rely on tree cutting. 65% of the raw materials come from recycled waste paper, 25% from imported or local eucalyptus wood pulp, and 10% from bagasse, bamboo, reed, wheat straw and other waste fiber raw materials

"it seems that the pollution problem of the paper industry in those days has been basically solved, but the backward problem has not been solved. Like my teachers, I place my hopes on my team and students to continue to do what I have not done." Chenkefu said, "our technology has no barriers, and we welcome sharing technological achievements with other enterprises in the industry. Only through the joint action of the whole industry can the paper industry remove the hat of a large polluter and truly realize green development."

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