The development of papermaking technology can not be separated from the continuous updating and improvement of equipment.
The development of papermaking technology is inseparable from the continuous updating and improvement of equipment. The innovation of equipment not only promotes the improvement of production efficiency, but also plays a key role in environmental protection, energy saving and product quality. The following is an analysis from three aspects: the key direction of equipment update, typical equipment upgrade cases and the impact on the industry:
First, the key direction of papermaking equipment renewal
1. Intelligent and automated upgrade
Intelligent control system: PLC (programmable logic controller), DCS (distributed control system) and Internet of Things (IoT) technologies are introduced to realize real-time monitoring and precise adjustment of the whole process of pulping, papermaking and drying. For example, real-time monitoring of pulp concentration, paper thickness and other parameters through sensors can automatically adjust the running speed and process parameters of the equipment, reduce manual intervention and improve stability.
Robot application: industrial robots are introduced in raw material sorting, finished product packaging, warehousing and logistics to replace repetitive work, improve efficiency and reduce labor costs. For example, the palletizing robot can realize the automatic stacking and handling of paper rolls.
2. Technological innovation of energy conservation and environmental protection
Energy-efficient equipment:
Using permanent magnet synchronous motor to replace traditional asynchronous motor can reduce energy consumption by more than 30%.
Optimize the steam system, and recycle the waste heat generated in the drying process through waste heat recovery devices (such as plate heat exchangers) to reduce energy consumption;
Popularize low-energy pulping screening equipment such as hydraulic pulper and low-pulse screen to reduce power consumption in pulping.
Environmental protection treatment equipment upgrade:
Introduce membrane separation technology (such as ultrafiltration and reverse osmosis) to treat papermaking wastewater, realize the recycling of water resources and reduce the consumption of fresh water;
Adopt high-efficiency air flotation machine, anaerobic bioreactor (such as UASB) and other equipment to improve the wastewater treatment effect and ensure that the discharged water quality meets the environmental protection standards;
Supporting waste gas treatment equipment (such as bag dust collector and activated carbon adsorption device) to reduce pollutants such as sulfide and dust volatilized during pulping.
3. Research and development of large-scale and high-speed equipment
Large paper machine: develop a high-speed paper machine with a width of more than 10 meters and a speed of more than 2000 meters per minute, and significantly improve the single machine capacity. For example, the annual output of some high-grade cultural paper machines can reach hundreds of thousands of tons, which is 5-10 times higher than that of traditional equipment.
Continuous pulping equipment: promote continuous digester to replace intermittent cooking equipment, realize continuous production in pulping process, shorten process time and improve raw material utilization (for example, wood pulp yield is increased by 5%-8%).
4. Equipment related to product quality improvement
High-precision coating and calendering equipment: scraper coater, soft roll calender and other equipment are used to improve the smoothness and gloss of paper surface and meet the quality requirements of high-end printing paper, coated white board paper and other products.
On-line detection equipment: install on-line detection devices such as laser thickness gauge and paper air permeability detector to monitor the physical properties of paper in real time, adjust the process parameters in time and reduce the rejection rate.
Second, typical equipment upgrade cases
1. pulping process: from chemical pulping to biological pulping.
Traditional equipment: Alkali/sulfate cooking is the main method, which consumes a lot of caustic soda and produces black liquor pollution.
Upgrade equipment:
Introduce biological pulping equipment, decompose plant fiber by microbial enzymes, reduce the dosage of chemicals, reduce energy consumption and pollution;
Itc (displacement cooking technology) * * Supporting equipment: Optimize the cooking process by countercurrent displacement principle, shorten the time, improve the pulp strength and reduce the load of black liquor treatment.
2. Paper-making link: the popularity of crescent toilet paper machine.
Traditional equipment: fourdrinier paper machine produces toilet paper, which has some problems such as low speed (about 1000m/min) and insufficient paper softness.
Upgrade equipment:
Crescent toilet paper machine: The speed can reach 2,000-2,500m/min, and it is formed by single-layer or multi-layer inclined net. The paper produced has good uniformity and high softness, and is suitable for the production of high-end household paper.
3. Waste treatment: sludge recycling equipment.
Traditional treatment: direct landfill or incineration of papermaking sludge has many problems, such as large land occupation and secondary pollution.
Upgrade equipment:
Using plate-and-frame filter press and thermal drying equipment, the water content of sludge is reduced from more than 80% to less than 30%, and it is made into biomass fuel or used to produce building materials (such as sludge brick-making equipment) to realize waste resource utilization.
Third, the impact of equipment renewal on the paper industry
1. The production efficiency has been greatly improved.
Large-scale, high-speed equipment has significantly improved the unit capacity, for example, the per capita annual capacity of modern paper mills has increased from dozens of tons of traditional technology to hundreds or even thousands of tons.
2. Product structure optimization
High-precision equipment supports the production of high value-added products (such as food packaging paper, electronic specialty paper, etc.), and promotes the transformation of the industry to high-end. According to statistics, the proportion of specialty paper production in China has increased from about 10% in 2010 to more than 25% in 2023.
3. Environmental protection and energy saving have achieved remarkable results.
Advanced equipment helps the industry reduce energy consumption and pollutant emissions. For example, after adopting high-efficiency energy-saving equipment, the comprehensive energy consumption per ton of paper (standard coal) will drop from 1.5 tons in 2015 to about 1.1 tons in 2023, and the wastewater discharge will be reduced by more than 40%.
4. Industry concentration has increased.
Small and medium-sized enterprises gradually withdraw from the market due to the high cost of equipment upgrading. The head enterprises form cost and technical advantages by purchasing advanced equipment on a large scale, and the industry CR10 (the concentration of the top ten enterprises) has increased from 35% in 2010 to more than 55% in 2023.
Fourth, the future development trend
Green manufacturing equipment: further promote zero-emission papermaking technology-related equipment (such as closed circulating water treatment system) to realize "zero wastewater discharge" and chemical recycling.
Digital equipment: Combining artificial intelligence (AI) with big data, develop predictive maintenance system, and early warn faults through equipment operation data to reduce downtime.
Biomass comprehensive utilization equipment: explore the high-value utilization equipment of lignin, hemicellulose and other by-products in pulping process (such as equipment for extracting lignin to prepare new materials) to improve the utilization rate of resources.
In a word, the continuous updating of equipment is the core driving force of papermaking technology iteration. In the future, the industry will rely on equipment innovation to develop in an intelligent, green and high-end direction to achieve a win-win situation of economic and environmental benefits.
