IJERT-Simplified Approach for Paper Drying Modeling Using Matlab (original) (raw)

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Modelling drying process in paper manufacturing

2012

Euroresinas produces different types of resin-impregnated paper at their factories. After the paper goes through the resin bath, it undergoes a drying process which is a fundamental step in the process. Although the temperature is controlled by a heating system, the actual values inside the chain of dryers are only measured at a few points away from where the paper is. The company would like to be able to model the temperature profile inside the dryers to better understand problems such as dusting and sticking, as well as the optimization of different variables related to bathing and drying times and energy consumption.

Dynamic Simulation of Yankee Drying of Paper

Introduction: Drying of paper using Yankee dryers is a complex process. The fundamental factors effecting paper drying in a Yankee are heat transfer through the condensate layer, heat transfer through the yankee shell, heat transfer from the yankee surface to the paper through any other intervening layers like crepe promoter etc., affinity of water to the fiber because of fiber-water isotherm, heat transfer from the hot air in the yankee hood and humidity effects of the moisture present in the hot air. As is evident, this is a highly interrelated process even during steady state operation. In addition, yankee systems exhibit a high degree of dynamic behavior during start-ups, shut downs and grade or production rate changes. A large part of the dynamics is also seen due to the dynamic behavior associated with the equipment around the Yankee such as thermo-compressors, condensate tanks etc. A dynamic model of a Yankee drying system will help in the analysis of these interactions.

Portuguese Study Groups ’ Reports Report on “ Modelling drying process in paper manufacturing ”

2012

Euroresinas produces different types of resin-impregnated paper at their factories. After the paper goes through the resin bath, it undergoes a drying process which is a fundamental step in the process. Although the temperature is controlled by a heating system, the actual values inside the chain of dryers are only measured at a few points away from where the paper is. The company would like to be able to model the temperature profile inside the dryers to better understand problems such as dusting and sticking, as well as the optimization of different variables related to bathing and drying times and energy consumption. Portuguese Study Groups’ Reports 1

Theoretical study of combined heat and mass transfer process during paper drying

Heat and Mass Transfer, 2005

Theoretical and experimental study of the paper drying process are presented. A mathematical model developed for combined heat ad mass transfer analysis of paper drying is given for both impinging air jets and through air drying methods. In this model, it is simply assumed that during the drying period of the paper has porous media and on the drying surface the vapour pressure of the evaporating liquid remains at a quasi-saturated value corresponding to the temperature of the liquid. The calculated transient paper temperatures in both methods agree well with the experimental results.

A Mathematical Model of Paper Drying

Mathematical Modelling and Analysis, 2000

The mathematical model of wood drying based on a detailed transport phenomena considering both heat and moisture transfer have been offered in the article [5]. We apply this model to quickly moving paper sheet. The range of the moisture content correspond to the period of drying and only vapor movement in the web is possible. By averaging we have obtained the desired model as a system of two nonlinear first order ordinary differential equations.

A state model for the drying paper in the paper product industry

IEEE Transactions on Industrial Electronics, 1997

The purpose of this paper is to present a state variable model for the drying section of a paper-making machine. This model is based on the mass and energy balance relationships written for steam, paper, cylindrical heater wall, and moisture. These relationships give a set of six nonlinear partial derivative equations. The form of these equations changes somewhat from one cylindrical heater to another. The solution for this model yields the operating parameters needed to achieve the desired steam temperature while obtaining good paper drying. Boundary conditions are specified by a stochastic generator, and initial conditions are obtained by solving the static model. The dynamic model is presented in [1]. In this paper, we present only the state variable model for the paper drying, as well as comparing the obtained results with dynamic model results. Solving the set of differential equations with respect to the boundary conditions, we obtain the standard form of the state representation, which represents the dynamic version of the model used for process control. In conclusion, it can be said that the consistency of the model with experimental results seems to be reasonably good and can be used for process control.

An experimental simulation model for coated paper drying

Brazilian Journal of Chemical Engineering, 2013

Due to the lack of information regarding the phenomena of mass, heat, and momentum transfer in coated paper drying, substantial research work still needs to be done. A simulation model for coated paper drying is introduced which integrates heat and mass transfer mechanisms. In the model, the coated paper was assumed to have 3 layers (coated layer, wet and dry layers of the base paper), in which the thickness of each layer is a function of drying time and condition. The thickness of the wet layer of the base paper was considered to be a function of water permeability rate that in turn is a function of the moisture diffusion coefficient, time and drying rate. Movement of vapor resulting from evaporation in the middle layer was assumed to be a combination of laminar bulk flow and molecular diffusion. Radiation absorption was used as a diminishing exponential model, which depends on moisture content. Hot air and super heated vapor were used as drying fluids. Functional variables were temperature, drying fluid velocity and delay time. To verify the simulation results two compositions were applied for the coating suspension. The simulation results matched well with experimental outcomes.

Modeling Drying of a Coated Paper

International Journal of Modeling, Simulation, and Scientific Computing, 2014

Drying of a coated paper is modeled and simulated. The paper sheet is assumed to form three zones, and each zone has its own drying mechanism. Coupling of energy and mass balances must be used in order to solve differential equations. The simulations are carried out in various drying conditions i.e., only hot air drying, only radiant drying, and mixed hot air-radiant drying. Also the effect of one side and two side assumption on evaporation is studied. Effect of venting air speed and radiant heat source presence and its distance from the drying surface on the drying of a coated paper has been studied. It is found that both distance and venting air speed are inversely related to drying in mixed hot air-radiant drying. Both surfaces participate in evaporation however, during the last time of drying, no difference between the upper and the bottom surfaces exist.

Generalized drying curves in conductive/convective paper drying

Brazilian Journal of Chemical Engineering, 2000

The drying of paper (cellulose) sheets over heated surfaces, under natural and forced air conditions is studied. Samples were placed over the upper surface of a metallic box heated by a thermostatic bath. The system is exposed to ambient air under two different conditions: natural convection and forced convection provided by an adjustable blower. Samples consisted of pure eucalyptus pressed cellulose (about 1 mm thick). Moisture content of sheets (dry basis, d.b.) was determined from their constant weight in an oven at a temperature of 105°C. The influence of initial paper moisture content, drying (heated surface) temperature and air velocity on the drying rate curves behavior was analyzed under different drying conditions and studied through generalized drying rate curves. A model was then successfully employed to fit them.

The potential for higher drying rates in cylinder drying of paper

1992

A simulated dryer was used to examine heat flux and drying rates possible with a highintensity gas-heated paper dryer. We examined the effects of surface temperature, felt tension (mechanical pressure), and other factors on drying rates in preheated and room-temperature sheets at 60% solids. The results of this study show that significant gains in drying rates may be achieved by increasing the applied pressure when the surface temperature exceeds 200°C. While the absolute values of heat flux observed in this study are larger than those seen in a mill, the data are still useful in determining key trends such as the increase in heat transfer that may occur with increased pressure and temperature. Future work is underway to better simulate industrial drying. However, the data raise the possibility that industrial cylinder drying may be operating well below its potential. BACKGROUND To overcome the practical limitations of steam as the heat source in drum driers, ABB Flakt Ross has deve...