Novel Parameter Identification Method for Basis Weight Control Loop of Papermaking Process

The basis weight control loop of the papermaking process is a non-linear system with time-delay and time-varying.It is impractical to identify a model that can restore the model of real papermaking process.Determining a more accurate identification model is very important for designing the controller of the control system and maintaining the stable operation of the papermaking process.In this study,a strange nonchaotic particle swarm optimization(SNPSO)algorithm is proposed to identify the models of real papermaking processes,and this identification ability is significantly enhanced compared with particle swarm optimization(PSO).First,random particles are initialized by strange nonchaotic sequences to obtain high-quality solutions.Furthermore,the weight of linear attenuation is replaced by strange nonchaotic sequence and the time-varying acceleration coefficients and a mutation rule with strange nonchaotic characteristics are utilized in SNPSO.The above strategies effectively improve the global and local search ability of particles and the ability to escape from local optimization.To illustrate the effectiveness of SNPSO,step response data are used to identify the models of real industrial processes.Compared with classical PSO,PSO with timevarying acceleration coefficients(PSO-TVAC)and modified particle swarm optimization(MPSO),the simulation results demonstrate that SNPSO has stronger identification ability,faster convergence speed,and better robustness.

Development and Evolution of Papermaking in Ancient China based on the Uses and Forms of Paper

In the past,scholars have divided the history of Chinese papermaking into different stages based on the development of ancient papermaking technology,emphasizing the development and progress of papermaking in different historical periods but paying less attention to the changes in the form of paper.Here,the stages are defined based on changes in use and function rather than technological developments.When this approach is combined with the history of printing,books,calligraphy,and painting,the history of Chinese papermaking can be divided into the writing paper,writing and printing paper,printing paper,and calligraphy and painting paper periods.Different periods of paper have significant differences in texture,form,and performance owing to their different applications.This significant difference provides a reference for the identification of ancient papers and reveals the internal connection between the history of printing,books,calligraphy,painting,and papermaking.

Preparation and application of cationized pulp fiber as a papermaking wet-end additive

Cationized pulp fibers （CPF） were prepared by the adsorption of a novel biodegradable cationic ester quaternary ammonium salt （31441） on bleached softwood kraft pulp fibers. The optimized conditions for the CPF preparation were： 4% of 31441 （based on oven-dry pulp）, 80℃ and 30 rain. The CPF was characterized by FT-IR, SEM and XPS. Experimental results showed that the CPF improved the retention of precipitated calcium carbonate （PCC） filler significantly. With 0.9% CPF （based on oven-dry pulp）, the retention of PCC increased from 57.53% to 72.21%. The physical properties of paper were also slightly improved. The tensile strength and burst strength of the paper with CPF were higher than those with CPAM. CPF addition had no effect on the stock drainage.

Review of energy consumption research for papermaking industry based on life cycle analysis

Papermaking industry is a high-energy-consuming industry with long supply chain.The growth of paper product demand further intensifies the need of energy consumption.Energy saving through the full supply chain has become a focal point for long-term sustainable development of the papermaking industry.This paper reviews the advances in life cycle analysis for the papermaking industry in recent years.All the stages from the full supply chain are involved to give a panoramic overview of the papermaking industry.The object of this paper is to provide scientific basis to industry and decision-makers with profound understanding of the energy consumption and energy saving potential in a life cycle perspective.

Preparation of adhesive for bamboo plywood using concentrated papermaking black liquor directly

Adhesive for bamboo plywood prepared directly using lignin existing in the black liquor as a kind of material replacing phenol was proposed on the basis of the same structural properties of lignin and phenol. The results indicate that the reaction time of black liquor methylating is 30min, when the ratio of alkali to formaldehyde is controlled at approximately 0.20, decomposition rate of formaldehyde is the lowest and the effect of black liquor methylating is the best, the optimal molar ratio of phenol： formaldehyde to NaOH to H2O of preparing phenolic resin is 1.00 ： 1.50 ： 0.50 ： 9.00, and the suitable viscosity is 27 - 30 Pa· s. At different mass ratios of methylated black liquor to phenolic resin, all terms of performance of black liquor phenolic resin are excellent and satisfy the requirement. All terms of performance of bamboo plywood prepared using this technique are hetter than that of excellent bamboo plywood of national criteria. Using this technique, the cost is depressed by 28.69% without altering the traditional adhesive producing technique flow, and without using additional equipment.

Application of Cellulose Nanofibril as a Wet-end Additive in Papermaking:A Brief Review

Recently,cellulose nanofibril(CNF)has emerged as a promising,sustainable reinforcement with outstanding potential in material science.Owing to the properties of CNF,it has been explored in food,cosmetic,and pharmaceutical applications,as well as in industrial applications such as paints,drill muds,packaging,and papermaking.The application of CNF in papermaking is expected to be implemented in the near future to broaden the commercial market of cellulose.Numerous studies and patents have reported on the manufacturing,properties,and applications of nanocellulose.This present paper focuses on the recent progresses in the application of CNF as a wet-end additive in papermaking.

FUNCTIONS OF POLYAMINES IN ROSIN SIZING UNDER NEUTRAL PAPERMAKING CONDITIONS

Functions of the polyamines in neutral rosin sizing were investigated using X-ray photoelectron spectroscopy (XPS) and laser diffraction particle analysis. The polyamine with a higher charge density and a smaller unite size could retain more rosin and cover larger fiber surfaces. The XPS spectra demonstrated that polyallylamine (PAAm) and polyvinylamine (PVAm) could react with a rosin size to form a -OC-N-CO- structure, but polydimethylamino ethyl methacrylate (PDMAEMA) could not. The formation of this structure may be a key step for effective sizing.

Production of Bamboo Fiber Reinforced Fibrillated Poly(Lactic Acid)(PLA) Material Obtained by a Papermaking Process

A devised beating process was applied, which enabled the formation of slurry consisting of uniformly dispersed fibrillated polylactic acid（PLA） fibers with bamboo fiber, and the polymer material was obtained by a conventional papermaking process. Owing to the fast dewatering time, good repeatability and the facility to manufacture on a large scale, this process was used. It was revealed that the beaten PLA fiber was overall in machinery extrusion by the results of optical microscope and scanning electron microscope（SEM） observations. The improvement in the tensile index, burst index, tear index and other mechanical properties was considered as a key benefit as a result of adding bamboo fiber.

Wet Pressing Models to Reduce Energy Consumption in Papermaking

Improved wet pressing reduces the need for drying and consequently energy needed in papermaking. Accordingly, it is desirable to optimize wet pressing, but the process is very complex with many interacting variables. It is therefore desirable to employ a mathematical model that accounts for the major variables to estimate the effects of changes in equipment and operating variables. This paper descibes such a model called the Decreasing Permeability Model (DPM). Mill and pilot plant applications over a wide range of basis weights for paper and paper board are described.

Coaxing Polysaccharide Granules into Supramolecular Biocolloidal Additives for Papermaking

In light of developments in polysaccharide-based sustainable processes involving supramolecular interactions,we herein present our findings pertaining to coaxing polysaccharide granules into functional supramolecular biocolloids.Translucent biocolloidal dispersions containing various forms of starch are facilely designable,essentially built upon complexation between disassembled native cornstarch granules and amphiphilic ligands.Oily moieties of guest molecules are dynamically attractable into cavities of helical structures,with cationic groups pointing toward the bulk phase.This noncovalent attraction can generate core-shell biocolloidal particles.The significantly higher gelatinizability of freeze-dried biocolloids in contrast to native cornstarch granules is attributable to complex formation,and a homogenous dispersion is readily formable at room temperature.Our results also show biocolloids'ligand-related antibacterial activity.The use of biocolloids as wet-end additives for biofiber assemblies(cellulosic paper)can enhance mechanical strength,fines retention,and filler bondability.Supramolecular biocolloids with positively charged,translucent,easily gelatinizable,antibacterial,and polysaccharide-bondable functionalities would find tailorable use in the paper industry.

THE PULPING AND PAPERMAKING CHARACTERISTICS OF YOUNG L.GMELINI AND B.PLATYPHYLLA

5, 10, 15, and 20 year old Larix gmelini and Betula platyphylla were used as pulping raw material in the research. The examination of young L. gmelini and B. Platyphyllafibrous structures showed that the fiber length and ratio of length to width of 5 years old L. gmelini noticeably differed from that of mature L. gmelini. but that of 5 year old B. platyphyllawere nearby equal to that of mature B. platyphylla. The research results indicated that 15 years old B. platyphylla and 20 year old L. gmelini were best suited to pulping among the eight experimental raw materials; 10 years old B. platyphylla and 15 year old L. gmelini were optimal to the ratio of beating degree increment and corresponding beating time. The pulp characteristics of 15 year old B. platyphylla and 20 year old L. gmelini were similar to those of mature wood, and it was feasible to consider 15 years to B. platyphylla and 20 years to L. gmelini as their rotation period; 10 years and 15 years as their thinning cycles for the papermaking forest base.

A Neural Network Controller for Basis－weight Control of Papermaking Processes

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Indoor Particle Contamination in Airlaid Papermaking Workshop

An onsite testing based on eight-site air sampling was carried out in an airlaid papermaking workshop in Tianjin, China. By theoretical calculation, super absorbent polymer （SAP） size and its existent state in indoor static airflow were obtained. SAP content in the sampled air was tested through chemical analysis method and found to be 3.0-7.2 times that of the human health limit in production areas. The concentrations of total suspending particles （TSP） and respirable particles were achieved by weighing. Particles of the most concern differ for varied function areas. Particles smaller than 10μm are mostly produced in the main production process, and 73%-90% particles generated in packing areas are larger than 10μm. SAP raw material particles can easily changed to suspending form by inevitable extrusion and frication. Correlation between respirable particles and TSP agrees well with that in atmospheric environment.

The Protection and Inheritance of the Traditional Papermaking Process: A Case Study of the Zhang Paper Workshop

The Zhang Paper Workshop preserving the complete traditional papermaking process has been praised by experts as “the living fossil of Chinese papermaking”. Due to the impact of industrial papermaking, however, the traditional papermaking has gradually lost its market advantage, and the Zhang Paper Workshop prevailing for a time is already on the decline. In order to retain this precious cultural heritage, for more than 10 years, the Gleaners has spared no effort to provide various efforts to papermakers and has found a way out for the manual papermaking, and results have been achieved. How to protect and inherit the traditional papermaking process under the premise of conserving the ecological environment and maintaining the integrity of the papermaking process, and establish the Zhang Paper Workshop as a place for spreading the concept of nature conservation and cultural heritage protection is an urgent problem to be solved. This requires the support of policies, the investment of funds and the upgrading of technology, as well as the promotion of understanding and the cultivation of feelings.

Application of Lignin in Papermaking Waste Liquor in Slope-site Vegetation Construction

Exploration and practice were made to the mechanism, methods, func- tions, characteristics and application effects of the chemical modification of lignin in papermaking waste liquor used as base planting material additive to the vegetation construction in difficult slope-site. The results showed that after chemical modifica- tion, the base planting material additive had a lot of functions and good perfor- mance, which could effectively improve the water retention, fertilizer maintenance and nutrient-supply capacity of the plant matrix, as well as the stress resistances of plants, and it was especially suitable for the vegetation construction in the high and steep rock slopes where hydrothermal conditions were especially harsh and the construction and maintenance were very inconvenient to carry out. It provided new ideas and supporting technical to solving industry common problems, such as easy sliding of base planting material, easy degradation of vegetation, and provided a new approach for resource utilization of papermakina wastewater.

Ministry of Water Resources and Ministry of Industry and Information Technology Issued Seven Industrial Water Quotas Including Papermaking

On December 30^(th), 2020, in order to further promote water conservation, Ministry of Water Resources and Ministry of Industry and Information Technology issued a notice on seven industrial water quotas including papermaking, and the quota standard was came into effect on March 1^(st), 2021.

Catalytic ozonation treatment of papermaking wastewater by Ag-doped NiFe2O4 : Performance and mechanism

The catalytic ozonation treatment of secondary biochemical effluent for papermaking wastewater by Ag-doped nickel ferrite was investigated.Ag-doped catalysts prepared by sol-gel method were characterized,illustrating that Ag entirely entered the crystalline of Ni Fe2O4 and changed the surface properties.The addition of catalyst enhanced the removal efficiency of chemical oxygen demand and total organic carbon.The results of gas chromatography-mass spectrometer,ultraviolet light absorbance at 254 nm and threedimensional fluorescence excitation-emission matrix suggested that aromatic compounds were efficiently degraded and toxic substances,such as dibutyl phthalate.In addition,the radical scavenging experiments confirmed the hydroxyl radicals acted as the main reactive oxygen species and the surface properties of catalysts played an important role in the reaction.Overall,this work validated potential applications of Ag-doped Ni Fe2O4 catalyzed ozonation process of biologically recalcitrant wastewater.

Converting a Dilute Slurry of Hollow Tube-like Papermaking Fibers into Dynamic Hydrogels

Commercially,assembly-directed packing of hollow tube-like papermaking fibers with widths of roughly 10–50μm)into sustainable microfibrous bioassemblies(i.e.,paper-based products)starts with a dilute fiber slurry.In this process,a huge amount of water is required to disperse and transport fibers,which also facilitates colloidal interactions and formation of interfiber bonds.To form bioassemblies in their dry states,unit operations associated with dewatering and drying are routine practices,and treatment of the generated wastewater is a necessity.We herein present a facile,easily scalable concept of converting fiber slurry into dynamic hydrogels by using chemical additives(similar to papermaking wet-end additives),but without water removal.We used a typical group of additives as an example in an attempt to demonstrate the applicability of the concept.With boron-based dynamic chemistry as a key theoretical foundation,the combination of crosslinking and hydrogen bonding can lead to the formation of phase-reversible,self-healable,and stretchable hydrogels.Essentially,the characteristics of hydrogels are facilely tunable,and process parameters such as polymer dosage are rather critical.It is worth noting that fibers can act as a structural skeleton or mechanical support for tailorable design of hydrogels.The concept demonstrated in this study provides insights into value-added utilization of mass-producible biopolymeric fibers in accordance with existing industrial facilities.Fiber-based hydrogels would find use in diversified applications:toys,3D/4D printing materials,soft robots,drug delivery systems,among others.

The Building of Papermaking Enterprise's Recycling Economy Evaluation Index System Based on Value Flow Analysis

At present,the research on circular economy has made a lot of substantive results both at home and abroad.But for the papermaking enterprise,which is the representative of the light industry,few studies have analyzed the evaluation index system of circular economy.Since the current material flow analyses have limitations that the researchers cannot calculate materials with different units.The authors take advantage of the intrinsic correlation between the basic principle of value flow analysis and circular economy,and then analyze the dynamic changes of material flow and value flow through enterprises internal production process.Considering the resource output,the authors set up the layered structure of the evaluation index system,and then preliminarily determine the index form.Next,the authors use the frequency statistics analysis method to adjust indicators,forming a preliminary index system.After that,the principal component analysis and independent analysis are applied for screening.Finally,the authors build a circular economy evaluation index system for papermaking enterprise to provide scientific guidance for the process of circular economy.

Etherified dicyandiamide condensation copolymer as a wet-end additive for papermaking

Dicyandiamide-formaldehyde condensation copolymer was synthesized and used as a wet-end additive for papermaking.The retention of fibers and fines was used as a performance index.Factors were evaluated governing the performance of the polymer,including polymer dosage,pH and mixing time.The optimum dosage of the polymer was found to be 0.03%under the conditions.Overall,the polymer was effective in improving the drainage,as well as the retention of fibers and fines in papermaking process。