Pilot Paper Machine Research Articles

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.

The process dynamics of filler retention in paper using a CPAM/bentonite retention aid system

AbstractIn an effort to develop robust control strategies for the wet‐end of papermaking, an experimental program was carried out to model the dynamic behaviour of the filler retention in paper using a Fourdrinier pilot paper machine and a cationic poly(acrylamide)/bentonite retention aid system. A dynamic simulation model of the pilot paper machine was developed from first‐principles. To describe the wet‐end chemistry effect, the first‐pass retention was included in the model as a new independent variable. The important factors affecting the dynamics of the wet‐end are first‐pass retention and the parameters related to the white water circulation.

Real-Time Entropy Control of Stochastic Systems for an Improved Paper Web Formation

In this article, a new entropy control strategy has been implemented for the web formation at the wet-end of a pilot paper machine. The innovative idea of entropy control for stochastic systems has been proposed and proved to be applicable for this system. Through real-time tests, the effectiveness of the new modelling method and the robust controller design method has been demonstrated. The current research concerns only the influence of the polymer on formation quality, which may be insufficient for the requirements of the real paper industry. Further research should consider the retention system with fibre as well as filler. Therefore, other control inputs must be considered and the control strategy will be considerably more complex.

Implementing machine-directional basis weight control for a pilot paper machine

The model of a paper machine is very complex and difficult to describe completely by a mathematical model. There are a lot of parameters in both the wet and dry end of the machine and there is a very large time delay in the system which effects the quality of the paper being produced. Although the PID controller is widely used for these types of applications, it is often not tuned very well. In this work, a newly developed algorithm (Munro, The systematic design of PID controllers, IEE Colloquium in Robust Control: Theory, Software and Applications, Austin Court, Birmingham, 1999) is used for tuning the PID controller. Along with this controller, a Smith-predictive controller is applied to the plant and the transient and steady-state behaviours of these controllers are compared. Hardware and software implementations of the closed-loop control are also presented in the paper.

Design of fault diagnosis filters and fault-tolerant control for a class of nonlinear systems

This paper presents a set of algorithms for fault diagnosis and fault tolerant control strategy for affine nonlinear systems subjected to an unknown time-varying fault vector. First, the design of fault diagnosis filter is performed using nonlinear observer techniques, where the system is decoupled through a nonlinear transformation and an observer is used to generate the required residual signal. By introducing an extra input to the observer, a direct estimation of the time-varying fault is obtained when the residual is controlled, by this extra input, to zero. The stability analysis of this observer is proved and some relevant sufficient conditions are obtained. Using the estimated fault vector, a fault tolerant controller is established which guarantees the stability of the closed loop system. The proposed algorithm is applied to a combined pH and consistency control system of a pilot paper machine, where simulations are performed to show the effectiveness of the proposed approach.

The role of surfactants as rewetting agents in enhancing paper absorbancy

Although surfactants have been widely used as rewetting agents, however, little research on employing surfactants as rewetting agents for paper towel manufacture has been reported. In the present work, the role of surfactants in increasing paper absorbency was investigated with the paper made on the Manchester Institute of Science and Technology (UMIST) pilot papermachine. The experiments showed that surfactants significantly reduce the water absorbency time (WAT) of paper products, which is caused by both an increase in the average pore size and an increase in the hydrophilicity of fibres treated by the surfactants. The optimal dosage of surfactant required to produce a large reduction in WAT is related to the critical dosage needed to considerably increase the average pore size, which is about 0.2% (wt on dry fibres) or less. Although the increase in the water absorption capacity of paper caused surfactants appears limited, the surfactant do change the location of water so that more water is absorbed on the fibres instead of the pores of fibre network. Overall, a cationic surfactant produced the largest reduction in the papers water absorbency time.

An extended model for the estimation of flocculation efficiency factors in multicomponent flocculant systems

Abstract A model for the flocculation efficiency in flocculant systems consisting of up to three components (a low molecular weight (MW) cationic polymer, a high MW cationic polymer and an anionic particle sol) is presented. The model is based on the classical bridging mechanism. Extensions have been carried out to take into account the addition of low MW polymers making surface sites inaccessible for bridging polymers, the flocculation induced by the addition of anionic microparticles, and the conformation of the adsorbed high MW polymer layer. According to this model, the collision efficiency is a function of the degree of surface coverage of the suspended particles by low MW polymer, the degree of surface coverage by high MW polymer, and the addition of a third component which interacts with adsorbed high MW cationic polymers. In the experimental work, the model was tested by determining adsorption isotherms, by flocculation experiments on suspensions of cellulosic fibres and by experiments on a pilot paper machine. The model was found to give a good qualitative description of the experimental results.

Retention Modelling and Control in the Paper Machine WET End

Retention control has largely remained unsolved, although it is one of the most important control loops still to be closed in the paper machine. In this paper retention modelling is done using multivariable time-series approach. Based on careful selection of vanables and model structure, several new control strategies are developed. Different feedback controls are successfully tested on a pilot paper machine. It is believed to be the first time when successful retention control has been reported in the literature.

A Self-Tuning Controller for Processes with Time-Varying Delay: Application to a Paper Machine Head Box

The paper develops a new method to estimate time-varying delay in self-tuning control. Another improvement to self-tuning is a novel way to vary λ weight in the cost function matrix Q. Both ideas were tested with computer simulation and proved successful.The basic reason for developing the new method was the application of self-tuning control to paper machine head box. Preliminary experiments with scalar self-tuning control were carried out at a pilot paper machine of Tampella Ltd in Inkeroinen, Finland. The tried scalar incremental self-tunig controller worked well but the responses showed some sluggishness. Further experiments were performed at a laboratory-scaled head box at Tampere University of Technology. A new "hybrid" self-tuner, with a fixed proportional controller and a self-tuning part, gave surprisingly good results compared with PID control.

Gamma‐Irradiated Cationic Starches: Paper Surface‐Sizing Agents

AbstractCationic starches, precisely depolymerized by gamma‐irradiation (60Co), were dispersed in mild alkali and evaluated as surface sizes for bond paper on a pilot paper machine. The irradiated products had excellent dispersion properties, were well retained on fibers when sized wastepaper (broke) was repulped and had an ability to enhance paper properties that was comparable to that of starch‐based materials used commercially. A yellow corn flour, cationized by an essentially dry reaction process recently developed at this Center, was also radiolyzed and evaluated as a size. This latter product was unique in that all drying steps were eliminated in the preparation of a cationic ceral product of reduced viscosity.

ユーカリパルプの道管要素 ＩＩ ユーカリ道管要素の抄紙特性および化学分析値

Mechanical and chemical characteristics of eucalyptus vessel elements have beee studied with special reference to their effects on paper qualities. Any significant morphological changes of eucalyptus vessels during beating were not observed down to 440 ml freeness level, indicating that a more intense beating action should be applied to effect vessel breaking. From the paper-sheet forming study in which the separated vessel elements were blended with wood fibers at various vessel ratio ranging from 0 to 100%, it was found that the vessel elements tended to result in higher sheet density, reduced air permeability, lower stiffness, and deteriorated tensile, tear, plybond, and surface strengths. Intrinsic strength of vessel elements, and their inter-element adhesion were found to be considerably lower than those of wood fibers, which seems to be accounted for the greater part of the abovementioned effects.The separated eucalyptus vessel elements were dyed, mixed in paper stock furnish, and formed into paper sheets using a pilot paper machine. The results of this experiment indicated that the transverse distribution of vessel elements in the sheets were rather uniform, and that the vessels which were picked out in a high-tack offset printing corresponded to only a slight portion of total number of surface exposed vessel elements. The apparent density of eucalyptus vessels was calculated as 1.66 by author, which is considered to be considerably higher than that of wood fibers. A chemical analysis of seperated eucalyptus pulp components (wood fibers, parenchyma cells, and vessel elements) revealed that the pentosan content was highest in the vessel elements, whereas the pitch was localized mostly in the parenchyma cells and to a lesser extent in the vessel elements.

Modelling and parameter estimation of paper machine drying sections

Drying is a very important phase of papermaking. Improving its economic operation is then of great interest. Recent process analysis techniques by modelling, identification and simulation offer new perspectives for such studies.This paper describes a mathematical model based on a theoretical analysis of the physical phenomena that occur in multicylinder paper machine drying sections. The main design and working parameters of these processes are taken into account and computer integration of the equations leads to an overall model of the sheet drying process which is easily workable. This model is the basis of a parameter estimation method which has been developed to evaluate the heat and mass transfer coefficient values in industrial equipment. Results from a pilot paper machine are discussed and the influence of some working parameters on the transfer coefficient values are shown.

Starch Xanthide in Pilot Paper Machine Trials

AbstractStarch xanthate, an inexpensive water‐soluble derivative of starch, was oxidatively converted to the insoluble xanthide and evaluated on a pilot paper machine as a wet‐ and dry‐strength additive for unbleached kraft paper. Pilot data are compared with data reported previously that were obtained in laboratory evaluations. Differences observed in xanthide effectiveness on scale‐up from laboratory to pilot evaluations are described, and the variables responsible identified.

On the Manufacture of Vinylon Paper by the Beater Addition of Polyvinyl-alchol Powder on a Pilot Paper Machine

Nippon Synthetic Chemical Industry Co., Ltd. has developed a new form of binder, identified as a Gohsenol p-200, specifically designed for vinylon fibers.The effects of PVA powder as a bonding agent of vinylon paper have been mentioned in practice. The manufacture of vinylon paper on a pilot fourdrinier paper machine by using PVA powder as a bonding agent by the beater addition were studied.Physico-chemical properties of vinylon paper by using PVA powder is better than that of PVA fiber.PVA powder is convenient to handle and paper-making readily in the mill. For the most efficient results, care should be taken to select the preferred PVA powder for the specific need.