Journal of Hazardous Materials 144 (2007) 687–691 CFD methods for the reduction of reactive gas emission from a paper laminating machine Andras Horvath a , Christian Jordan a , Gerhard Forstner b , Peter Altacher b , Michael Harasek a,∗ a Institute of Chemical Engineering, Getreidemarkt 9/166, 1060 Wien, Vienna University of Technology, Austria b SIG Combibloc GmbH & Co. KG, Industriestrasse 3, 5760 Saalfelden, Austria Available online 30 January 2007 Abstract In cooperation with the world’s second largest manufacturer of beverage cartons (SIG Combibloc ® ) for liquid foodstuffs an innovative off-take for neutralisation of reactive gas in a paper laminating machine was constructed. A great challenge during engineering work was ensuring a high concentration of the reactive gas where needed and at the same time minimising work place impact in a machine basically without housing. Preliminary 2D-models of the machine geometry proved to be insufficient in describing all the governing flow phenomena. A simplified 3D-geometry containing all important parts of the complex machinery was necessary for accurate predictions. It was found that the driving force of air movement and transport of reactive gas (which acts as an adhesive agent) from the reaction zone in the interior of the laminating machine to the outside is a boundary flow caused by the rapid movement of carton material and rotating cylinders. A physically correct simulation result of the boundary flow is a premise for correct prediction of air flow in and around the machinery. Lacking experimental data (due to an inaccessible geometry) a worst case scenario was constructed by generating a grid and using turbulence models that maximised mass transport in the boundary layer region and thus emission of (tracer)gas from the machine. CFD simulations were done using the geometry preprocessor Gambit TM , and the finite volume solver Fluent TM . The results of the analysis of the emission paths from the machine were surprising and led to the construction of an effective off-take relatively far away from the emission source. The chosen position ensures low disturbance of highly sensitive flow patterns inside the machine and diffusive mixing, dilution and contamination of the surroundings. The effect of the new off-take is an immediate and significant rise in air quality in the vicinity of the laminating machine and ensures maximum allowed concentration in the plant area. The product quality furthermore is uncompromised by the working off-take which was another important goal of this work. © 2007 Elsevier B.V. All rights reserved. Keywords: CFD; Emission; Boundary layer; Lamination; Packaging 1. Introduction SIG Combibloc ® , produces large amounts of laminated bev- erage cartons. The raw cartons have a width of 1.4 m and are produced at a speed of 8 m/s. Treatment of the used polymer- film with reactive gas is necessary to enhance adhesivity to the paper-base and to ensure mechanical stability of the compound material. Due to the open design of the laminating machines they are prone to emission problems caused by air movement and pressure gradients inside the laminator. The main factor of (unwanted) air flow inside the machine is the rapid movement of paper and its attached boundary flow. To understand flow ∗ Corresponding author. Tel: +43 1 58801 15925; fax: +43 1 58801 15999. E-mail address: michael.harasek@tuwien.ac.at (M. Harasek). phenomena and construct efficient off-takes it is necessary to correctly simulate the boundary flow. 1.1. Problem description The production of cartons for liquid foodstuff implies the laminating of both sides of the carton and often the application of aluminium as additional barrier layer for oxygen diffusion. The various polymer films are produced in an extruder nozzle and immediately after contact with the carton cooled on a special roller. The carton is under constant tensile stress and has to be in contact with rollers approximately every meter of length to avoid uncontrolled oscillations of the carton surface. The individual operations are performed by three different laminating machines. They are here described as types “A”, “B” 0304-3894/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jhazmat.2007.01.096