Drying simulations using the Ircon Drying Simulation program (IDS)

The Ircon Drying Simulation program (IDS) is a powerful tool used to simulate the drying conditions in a coating machine. Reliable prediction is an essential part of designing the right combination and size of a new drying system. In response, Ircon together with CF Procsim GmbH has developed a simulation tool where different types of drying equipment can be tailored and varied in size and location, as well as different coatings and other process data. The program predicts the end-results as well the status at any point between the application of the coating and the end of the drying section. Detailed results are plotted, covering local evaporation rates, solid content, moisture and web temperatures.

The simulation can be used to predict the result of a new coater configuration or new paper grades. Both existing and new configurations can be simulated, as well as the location of the various items of equipment along the drying path.


The simulation will show the web temperature, moisture and coating solids as a function of the distance from the coating application. The coating gel point can easily be located as the First Critical Consistency (FCC) point and Second Critical Consistency (SCC) point. It is possible to check that the coating is not reaching critical conditions at any stage (such as boiling temperature). To verify and check the simulation, data can be entered from existing production. If this data is available, the simulation is very accurate.



Example of simulation results: 


IDS is a program that integrates measurements and thermodynamic modelling to predict the location of the gel points in the coating process, which is then used as a quantitative representation of print quality. The MD drying simulation is based on energy and mass balances, with an emphasis on modelling ambient and boundary air conditions. The energy consumption in different drying devices and quality control system (QCS) measurements at the beginning of each coater are used as simulation input values. The simulated web values can be compared with the QCS measurements at the end of each coating station. Web temperature measurements made during the drying process at the different MD positions of the coating station can be compared with computed values at the same positions. This is one of the most effective ways to apply model performance to a real machine.


IDS can be used effectively as a tool for optimising, upgrading or rebuilding a coating machine. This is especially true for modern, wide-span coating machines with high production rates. Optimisation results in significant improvements in drying performance and decreases energy consumption. Using energy effectively and at the same time maintaining or improving paper quality using lower-cost coating components requires knowledge of drying kinetics.




Air flow analysis using 3-D Flow-works software


When designing the IR and air dryers, extensive testing and simulations are required. By using modern 3-D air flow and heat transfer software, the amount of testing can be minimised. Heat transfer details, air flow patterns and local air pressures, velocities and other thermodynamic properties are visualised in the Flow-work software used by Ircon. This permits more optimisation and shortens the development time.



Example: Air velocity study of air nozzles.



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