Future technological development direction of pulp and paper industry

Academician Chen Kefu has been engaged in research and teaching of light industry, pulp and paper engineering for a long time. The engineering research fields include bleaching technology of medium and high concentration pulping, sheet forming technology, coating and coating technology, clean production technology and equipment of pulping and papermaking, key technology and equipment of modern paper machine; In the theoretical research areas of chemical fluid mechanics, fiber suspension rheology. He has edited or edited 9 books, published more than 200 papers indexed by SCI and EI, and has obtained more than 30 invention patents. He has won 1 second prize of National technological invention, 1 second prize of National Science and Technology Progress, 1 third prize of National Science and technology Progress, and 2 first prize of science and technology progress of the Ministry of Education. He was elected an academician of the Chinese Academy of Engineering in 2003.

Congratulations on the 40th anniversary of Zhonghua Paper. On the media platform of Zhonghua Paper, I have published "Reflections on the Sustainable Development of the Paper Industry in Guangdong Province" (May 2001), "Development and Countermeasures of the Private Paper Industry" (October 2001), "Some Issues on the Independent Innovation Strategy Research of China's pulp and paper Equipment Manufacturing Industry" (June 2006), and "Improving the independent innovation ability of the paper industry Construction of paper technology innovation system "(July 2007) and other articles.

"China Paper" and our country's reform and opening up synchronously, and China's paper industry to grow together. Now, the reform and opening up has entered a new era, the development of paper industry has entered a new period of adjustment and upgrading, and China Paper has entered a new stage of integration and development of old and new media. This paper discusses the new direction and new goal of engineering technology in the field of papermaking industry in China.

For papermaking advanced countries, most of the advanced technology has been mature application; Energy conservation and emission reduction, clean production, has become the norm, the unit capacity of water consumption, electricity consumption, pollutant emissions are within the scope of the country and society, has embarked on the road of green development; The design capacity, running speed and intelligent control of the equipment manufacturing industry have met the needs of the industry.

Some experts believe that the current pulp and paper technology of advanced countries in the world is enough to continue to use for many years. However, in order to promote the development of the paper industry, it is necessary to explore the future development of engineering science and technology in the field of paper making, and formulate the future research and development focus of engineering science and technology, that is, the medium and long-term development strategy.

1 Future major scientific and technological plans for advanced areas of pulp and paper making

1.1 Early European region

The Federation of European Paper Industries (CEPI) launched the "Forest Fiber Industry Roadmap 2050" in November 2011. The main objective of the road map is to find out how CO2 emissions can be reduced by 80% while generating more than 50% added value. Breakthrough technologies are needed to achieve this set goal. This means that if these breakthrough technologies are required to be fully deployed by 2050, then they must be commercially available by 2030.

CEPI first establishes the concept of breakthrough technologies (technology list), which requires that these breakthrough technologies can be used in industry after 10 to 20 years. A total of 8 technical concepts, such as the successful implementation of these technologies, will create better opportunities for the industry, make the industry more competitive and create more value in the future, and promote the sustainable development of the pulp and paper industry.

The future breakthrough technologies announced by CEPI are:

(1) Pulp production new technology - low eutectic solvent production of pulp

This technology will open up a new way to produce pulp at low temperature and atmospheric pressure. By using deep eutectic solvents, any type of biomass can be dissolved into lignin, cellulose and hemicellulose with minimal energy consumption, carbon emissions and residues, with the goal of achieving a 50% reduction in pulping energy consumption.

If the current pulping energy consumption can be reduced by 50%, this will be a major breakthrough in energy conservation in the pulping and paper industry, because pulping energy consumption is one of the largest energy consuming units in the pulping and paper process.

(2) Put forward the concept of waterless papermaking technology

At present, papermaking technology consumes a lot of energy and water resources, and the fiber concentration of pulp is only about 1%. The papermaking process requires complex equipment units to dehydrate, making papermaking the largest energy consumption unit. The international papermaking science and technology community has seen great disadvantages of energy-consuming papermaking methods with very low fiber concentration, and intends to find ways to solve this problem.

There are two technologies that belong to this concept: one is steam flow paper making, which is a production method that is very close to waterless paper making. The mostly dry fibers are blown to the forming area using steam stirring and subsequently settled into a web. The required water consumption is only equivalent to the current l / 1000. The second is the paper pulp curing technology, which is also a papermaking process technology with little water. The treated fiber is sent into a viscous solution to make a suspension with a concentration of more than 40%, and finally the solution is pressed out, and the fiber layer is solidified into a paper page by an auxiliary agent. Choose different auxiliaries according to different paper types.

(3) The technical concept of paper lightweight

Producing more products with less fiber, obtaining greater added value, and producing low-quantity products is one of the keys. Advances in page forming technology and raw material mixing technology will make future paper products more lightweight.

The paper is lighter, but the performance, especially the strength, remains the same, and also depends on the role of chemicals, and the application of chemicals is the key. In addition to solving the problems of page forming and mixing with chemicals, it is also necessary to solve the preparation of green chemicals.

(4) Nano-cellulose

Nanocellulose forms a stable colloidal suspension in water and can be mixed with thickeners and emulsifiers for application.

Plant fibers can be used to develop and produce nanocellulose products. Compared with other fibers, plant fibers have an inherent tendency to form thin films due to their high aspect ratio, high specific surface area and enhanced hydrogen bonding ability.

The advantages of nanocellulose solutions have been widely demonstrated. It can be predicted that this special material series of nanocellulose products can be used in paper, food, cosmetics, coatings, and can also be expected to be applied in electronics, medical and pharmaceutical applications, which will generate new huge business opportunities. The research on this kind of nanomaterials in the process of commercialization has made great achievements.

(5) Biomass refining technology

Put forward the concept of transformation and upgrading of pulp and paper, and will continue to pay attention to the sustainable development of woody biomass components. As the role of ionic liquids together with enzymes in lignocellulosic processing has been studied, various cellulose, hemicellulose, lignin derivatives and compositions have been developed for use in such materials as films, barrier agents, adsorbents, adhesives and composites.

(6) Put forward the concept of "paper machine doctor"

At present, the production capacity, speed and width of the paper machine that can be designed and produced by the equipment manufacturing industry have fully met the needs of the industry, and the diagnosis, maintenance and repair of the modern paper machine in operation have been mentioned in an important position, so the concept of "paper machine doctor" is proposed in the field of science and technology to ensure the normal operation of the existing paper machine and adapt to the new requirements.

1.2 North America

North America still regards energy saving, consumption reduction, carbon emission reduction, and transformation and upgrading of pulp and paper enterprises through biomass refining technology as the focus of future engineering technology.

(1) Energy saving. The energy consumption of the paper industry in the United States accounts for 10.5% of the total industrial energy consumption, which is one of the four energy consuming industries, and energy saving is the goal of key research and development technologies. Such as: ① Under the condition of ensuring the quality of the paper page, through the improvement of the dehydration press technology, the dryness of the paper page entering the drying part can reach 65%, an increase of 10% to 15%. ② Develop a new generation of pulp grinding machine to improve the yield of chemical pulp, reduce unit energy consumption by 20%, such as the use of biological enzyme pretreatment, heat recovery technology. ③ By increasing the concentration of black liquid washing, evaporation concentration and the concentration of entering the recovery furnace, the energy consumption of black liquid alkali recovery can be reduced by 50%.

(2) Reduce water consumption. Reduce water consumption by 50% through the development and implementation of new technologies for 100% recycling of wastewater. Focus on research and development of clean separation technology of pollutants in wastewater.

(3) Efficient and high-value utilization of plant resources. ① Improve the yield of chemical pulp and dissolved pulp, of which the yield of chemical pulp should reach 90% and above. ② Efficient use of wood waste and production process waste, put forward the concept of "biomass full component utilization". The specific technical scope of the biomass refining technology is similar to the woody biomass refining technology proposed by the European Paper Industry Alliance. ④ Study on high-value utilization of cellulose. In recent years, high value applications of Cellulose derivatives such as Cellulose Nanocrystal (CNC) or Cellulose Nanofibrils (CNF) have been developed.

2 For the future development trend of engineering technology in the field of international paper making

From the future research and development plans in Northern Europe and North America, two regions with developed international paper industry and technology fields, it can be seen that the main focus of the future development trend of engineering science and technology in the paper industry is:

(1) To further save energy consumption, water consumption and reduce the emission of pollutants, and future technology will still put this in the first place.

(2) To further save plant resources and realize the full utilization of plant resources. Although foreign wood resources are rich, nearly 50% of wood resources are used in the paper industry, but still put the saving of wood consumption in an important position.

(3) To achieve the transformation and upgrading of the paper industry through biomass refining technology.

(4) Clean separation of plant components, efficient and high-value use of cellulose, lignin and hemicellulose in plants and their ancillary products, improve the overall value of the paper industry.

(5) Modern paper machine technology has developed to a high degree, and the cost of maintenance will affect the operating profits of modern paper machines that are originally expensive. How to ensure the normal and stable operation of modern paper machines, its intelligent early warning and diagnosis, intelligent maintenance and maintenance have mentioned a new agenda.