High Speed Paper Machine Research Articles

Brief Review and Mathematical Modelling of Air Cushioned Pressurized Paper Machine Headbox

Today, the requirement of high grade papers is increasing day by day. To cater the need of high quality papers, new high-speed paper machines are being developed constantly. The whole economy of a pulp and paper industry depends on the quality of paper produced, quality of paper depends on the efficient operation of the major part of paper industry – paper machine. Paper machine is the heart of paper industry and has many subsystems. One of the important subsystem of paper machine is Headbox. To have the desired quality papers, efficient working of headbox is highly required. To have desired operation from headbox, its precise control is necessary. The precise modelling of headbox, leads to design of efficient controllers for its proper control to get the desired response. This paper presents the mathematical modelling of headbox along with a brief review of various research performed on headbox.

Dextrin-Poly(acrylic acid) Copolymer as an Additive for Surface Sizing with Oxidized Starch (II) : Effect on Strength and Drying Rate

Drying energy demand in the after-dryer section for the surface sized paper is an important economic factor in papermaking. Using an efficient sizing solution with high solids content and decreasing the pickup weight can reduce the drying energy requirement in the after-dryer section. A dextrin-poly(acrylic acid) copolymer was used as an additive for surface sizing of linerboard, and its effect on the mechanical properties of linerboard, and drying energy consumption were investigated. Results showed that, addition of dextrin poly(acrylic acid) copolymer had beneficial effects on the holdout of surface sizing starch and provided higher compressive and bending strengths. It was possible to reduce pickup weight by 23% while keeping the compressive strength and bending resistance at a similar level. Consequently, the reduced pickup resulted in higher dryness after surface sizing. Even though, drying analysis of wet sized sheets at a laboratory gave a lower drying rate when the copolymer was used as an additive, the result from a mill trial revealed that steam usage decreased significantly when the copolymer was used as an additive for surface sizing, which was attributed to the reduction in the pickup weight and improvement in holdout of the surface sizing agents on linerboard surface that is more pronounced on a high speed paper machine.

Paper Machine Bearing’s Temperature and Air-Velocity Optimization under Air-Oil Lubrication

The purpose of this resarch was investigated the air-oil temperature field distribution under air-oil lubrication and oil lublubrication, meanwhile also study the air-oil lubrication effect under different air velocity inlet the bearing cavities of the high-speed paper machine dryer section. Base on the CFD theory, the temperature field of CARB bearing outer ring and the velocity field of the bearing cavities were simulated by the FLUENT software.Result show that air-oil lubricatin can reach the same cooling effect is contras with oil lubrication in the same heat production by roller; the best air-velocity value of air-oil lubrication system is obtain for the change of temperature and pressure in bearing cavities. It is confirm that the air-oil lubrication is viable in the high-speed paper machine dryer section.

The Design of Decoupling Control System for Air-Cushioned Head Box of Paper Machine Based on Siemens S7-PLC300

Small motions will result in heavy influence to the production in high-speed paper machine, therefore, decoupling control is necessary. This passage Puts forward the opposite angles strategies to solve the function of decoupling aiming at solving the difficulty that occurs in practice, like the characteristic of hard-coupling and non-linear. According to the mathematics model of the flow box, decoupling the quantity of the two couplings in the processes. Meanwhile, Introduces the SIEMENS S7-300 PLC and the DCS system that is realized by the it.

The Design of Decoupling Control System for Air-Cushioned Head Box of Paper Machine Based on Siemens S7-PLC300

Small motions will result in heavy influence to the production in high-speed paper machine, therefore, decoupling control is necessary. This passage Puts forward the opposite angles strategies to solve the function of decoupling aiming at solving the difficulty that occurs in practice, like the characteristic of hard-coupling and non-linear. According to the mathematics model of the flow box, decoupling the quantity of the two couplings in the processes. Meanwhile, Introduces the SIEMENS S7-300 PLC and the DCS system that is realized by the it.

Innovative Design for Supply Mode of Steam in Drying Cylinder

This paper analyzed the dynamic state of the water ring, which is formed through the exothermic process of steam condensation, and its influence on heat transfer during the operating process of the high speed paper machine’s drying cylinder. The influence of perturbation on the flow condition of the water ring was also discussed. This information was used to design the steam-knife gas supply system in the drying cylinder. This system provides a so-called steam-knife to attack the water ring, which would change the dynamic state of the water ring’s fluid level. This would ultimately improve the heat transfer efficiency.

Numerical Simulation of Inner Flow Yield of Turbulence Generator of Papermachine Headbox and Structure Optimal Design

Turbulence generator is a key part of head box of middle or high speed papermachine. It is used to make the fiber flow smooth and steady. This paper gives simulation researches of the flow status on one turbulent tube of combined-turbulence generator, result shows that there is an optimal rate between the square tube and its equivalent diameter for Round-Square turbulence generator, and the equivalent diameter is 6.5. This guides the design of turbulence generator significantly.

The Application of High Speed Paper Making Technology

A new Mitsubishi high-speed paper machine development project has started in 1999 and the new product is called MJ series to produce quality paper at 2, 000 m/min operation speed. The MJ series has been developed in the course of the elementary study, program simulation, model test, and final verification on our pilot paper machine in Mitsubishi R & D center of Mihara, Japan.This paper presents the several challenges we were faced with when we tried high-speed operation on our pilot machine and also presents some useful products for stable operation.

Retention Aid Chemicals for High Speed Paper Machines

Retention Aid Chemicals for High Speed Paper Machines

三菱新シリーズ高速抄紙機

A new Mitsubishi high-speed paper machine development project has started in 1999 and concluded with product offering to the market in October 2001. The new product is known as MJ series and is designed to complement the current MH series Mitsubishi paper machines.The goal of MJ series paper machine is to produce quality paper at 2, 000 m/min operation speed while being an operator friendly product. The MJ series has been developed in the course of the intensive elementary study, program simulation, model test, and final verification on our pilot paper machine in Mitsubishi R&D center of Mihara, Japan.This paper presents the concept and features of the MJ series paper machine.

Wetend Concept of High Speed Paper Machine for Woodfree Grade

Paper making is a chain of process where every parts plays its own role. The future development targets of paper making have presented several challenges from headbox to reel. Here we introduced new OptiConcept. This New Concept will give the paper industry great economic benefits in many paper machines in the new century.

ヘッドボックスからプレスまで ＢＭ計メーカーから見たＣＤ坪量プロファイル制御について

Since the first Thermal Expansion type actuator (Thermatrol) was installed in domestic market in 1981. CD Weight Profile Control has been extremely growing in addition to Motor Drive and CP (Consistency Profiling) actuators. However, there seems to be some cases which can't keep the maximum control performance after the installation because of the change of control parameters, difference between the inlet position and QCS measurement position and the shrinkage pattern problem for the difference of machine conditions and some modifications.This report introduces the basic concept, control algorithms and a support tool to get parameters for CD Weight Profile Control to help with keeping and developing the existing control performance. Also a completely new concept of Spectra Foil Sensor to get a control profile instantly at Wet-End will be introduced. This sensor with High-Speed CD control will be expected to meet the customer demand to accomplish the High-Speed paper machine in near future.

ドライブシステムにおける最新技術動向

The paper machines have been requiring big capacity of drives and a lot of numbers of motors with their wide width and high speed.On the other hand, AC drives have become dominant in the drives application for paper machine, winders and coaters, because of its robust construction of motors and maintainability.This paper discussed the drive system technology especially required for wide width and high speed paper machine, and save-energy by AC drives.

Improvement of thermal and mechanical dewatering of paper in a hot press nip simulator

A laboratory-scale apparatus has been developed to investigate the thermal and mechanical dewatering of paper in the press nip of a high speed paper machine. The apparatus is basically a hammer-and-anvil-type dynamic press simulator modified to also simulate hot nip conditions. Using this device, dewatering experiments have performed on household paper tissue over a wide range of press conditions. The influence of different underlays, maximum pressure and temperature on mechanical dewatering by compression, capillary transfer between porous compressible materials, thermal drying and rewetting of the sheet are discussed.

抄紙機カンバスの選定・管理と高速化への対応に関する操業経験

Latly, the paper machines' runnability has been affected by various conditions. The speed of the paper machines has been increased in order to increase productivity. Also, the number of paper machines that have speeds which exceed 1, 000 m/min has increased.As you can see in the Recycle 55 Plan, recycle pulp is used not only in board paper, but also in various other paper grades, and its blending ratio has been increased. Proper management of these conditions is important in increasing the machines' runnability.In this report, We focus on the dryer felt. We use the mill's past experiences with various paper machines in the selection of suitable dryer felts for the high-speed paper machines. We also use past experiences in implementing countermeasures to the dirt problem.

伝熱性シングルカンバスのテスト結果

In the drying sections of high-speed paper machines, the single-run system is applied for the purpose of mainly preventing sheet-fluttering.We developed better heat-transferable dryer-fabrics in this system for more efficient drying of sheet web.Our special dryer-fabrics mentioned above for which some metalic fibers we partially used, has higher heat capacity and much improved heat-transferablity from drying cylinders to sheet web, compared with the conventional dryer-fabrics.We herewith report on the effects in the laboratory testing and in the actual applications of heat-transferable dryer-fabrics.

中性抄紙法の計装技術としてのゼータ電位測定に伴う問題点

Control of the zeta potential in neutral papermaking method is important particularly in the retention of calcium carbonatefillers, and the fixation of neutral sizing agents on pulp fibers. Problems associated with the wet end chemistry of neutral papermaking system are pointed out.Examples of the zeta potential control in neutral papermaking mills are presented, and various apparatus and ideas for zeta potential measurements applicable to process control are compared.Problems associated with the instrumentation of zeta potential measurements in the process control of neutral papermaking system are also pointed out. The main difficulty lies in estimation of the electrokinetic behavior of paper furnishes on high-speed papermachine because of the hetero-dispersing system and the fiber dispersion under dynamic shear force of the papermachine.The development of sensors capable of on-line measurement of the zeta pontential on high-speed papermachine and the construction of mathematical models capable of expressing the electrokinetic behavior of the paper furnishes under dynamic shear farce are prerequisites for incorporation of the zeta potential measurement in the process control system of the neutral papermaking system.

Internal Heat Generation in Press Roll on High Speed Paper Machine

With ever increasing paper machine speed, it has become desirable to minimize the sheet moisture content at the exit of press in order to maintain higher production efficiency and higher drying efficiency.For this purpose, elastoma cover materials for press rolls are to be kept as hard as possible and also nip pressure as high as possible, which is recent fundamental designing theme of high speed paper machine press part. This, however, constitutes a very severe condition for elastoma covered rolls and cover damages have taken place on press rolls in high speed paper machines. The reasons of these damages are mechanical problems and elastoma cover internal heat generation by hysteresis, both of which are caused by the above mentioned condition (i.e, high nip pressure at high speed). The hysteresis problem cam not be neglected as the machine speeds become higher. This paper shows results of analysis of this problem and calculates how much power is absorbed for internal heat generation in relatoin to total press section power consumption. These calculations were made on the basis of actual operating conditions on two machines. The calculations of actual amount of internal heat generation was also made by knowing the measurable factors for power consumption. Another investigation was performed by using experimental apparatus and a covered roll as a model at which point the generated internal heat damages the cover. It was found that the damage occurs when heat generating amount per rubber cover unit weight reaches up to 0.0840.087 kcal/kg/sec. In case of the two machines mentioned, nip pressure were 80 kg/cm, and machine speed was 600 m/min for one and 720 for the other. The generated heat was measured to be 0.0210.024 kcal/kg/sec. So, in these two cases, thermal safety factor is 34. In a machine of this size, however, if machine speed goes up to 1, 000 m/min, heat generation radically increased to 0.044 kcal/kg/sec (safety factor : 2), which will probably causes operation and maintenance trouble for elastoma covered rolls. Temperature distribution in the elastoma cover by internal heat generation appears higher from the surface to the inside. I would like, however, to leave this problem as a theme to be investigated in the future. The cover material tested in this report was polyurethane type synthetic material (hardness P & J 5).

抄紙機ドライパートの湿紙乾燥に関する理論的解析の問題点に対する若干の考察と高速抄紙機における湿紙乾燥の実際的な考察 ＩＩ

There exist very few reports or studies for the purpose of improving quality of final products, efficiency and operation by measuring and analyzing tendency of paper drying on dryer part actually operated wide and high speed paper machine. This is mainly because the higher the paper machine speed, the measurement of dryer part increase the possibility of production loss and is also more hazardous from safety stand point. I have measured moisture content distribution in each pocket of dry part and dryer surface temperature under special countermeasures against above mentioned difficulties and have investigated influences of so-called “chimney” and “ventury” effect together with relation to the uneven drying of products, of which results are presented in this paper. I have found unexpectedly high non uniform moisture and temperature profile in case of canvas air system dryer. The fact that cross machine moisture profile in the pockets of wet and dryers is not uniform, easily causes uneven drying which is impossible to be corrected by the subsequent dryers. Dryer surface temperature is high on back side because drying steam has too much superheat. “Chimney” and “ventury” effects have no negligible influence and I have been able to confirm many facts which hitherto were only conjectures. This measurement was executed on a paper machine of 6, 960 mm wire width and 650 m/min. operating speed. The measuring method was as shown in fig. 9.

Application of process simulation to operator training and startup of a high-speed paper machine

Because of the complexity of operation of a paper machine, a simulation of operation would provide three avenues through which better startup and operation could be obtained: (1) engineering evaluation, (2) operator training, and (3) control-program evaluation. Prior to the startup of a new high-speed paper machine, a simulation of the stock system where the suspended fibers are formed into a sheet of paper was undertaken. Basic information on the steady-state and dynamic be havior of such a system was obtained on a highly instru mented paper machine having components similar to those of the new machine. The system was analyzed one component at a time to fit available theoretical equations with minor modifications. This allowed reasonable extrap olation and reassembly of the system to describe the new machine. An important factor in describing such a system was the transport lag in the pipelines. This facet of the simulation was accomplished with prewired Padé approximations of these lags. A second important characteristic in describing a paper machine in real time is the long time-constants involved in the rates of change. These may run as long as 10 minutes. A replica of the main control panels was constructed for use as a training aid for the operating crews of the new machine. The panels were programmed on the computer to respond to upsets and grade changes as part of an inten sive training program for the operators. Exploitation of the simulation system is still in progress. It is evident, however, that the smooth startup resulted from careful planning and effective operator training.