1. Electrostatic precipitators (ESPs) simulated with Fluent Renata Favalli, PhD. Eric Robalinho, MSc. Joel Maia, Eng. Renato Greco, Eng. Jorge Daher, Eng. 2008 ESSS South American ANSYS Users Conference

2. ENVIRONMENTAL SYSTEMS MAINTENANCE & ASSEMBLING STEEL WORKS LASER CUTTING COMBUSTION AND ENVIRONMENT Enfil Group of companies

3. Founded as C.Greco in 1966 by Prof. Clemente Greco. After 2004 became part of Enfil Group of companies; Projects for systems and equipments, such as burners, dryers, gas cleaners and coolers, in different industrial sectors (cement, fertilizers, mining, food stuff, etc.); Since its foundation has been developing CFD modelling in a variety of equipments; Acting with the Brazilian cement industry since the 80’s; Acting with the international cement industry since the 90’s; More than 300 burners for rotating kilns installed around the world.

4. Clients around the world

5. Brazilian company based in São Paulo with an office strategically placed in Vitória, ES; Specialized in maintenance, upgrades, systems optimization and personnel training; Technological agreement with: NSC – Nippon Steel Corporation (Japan) ENELCO – Environmental Elements Corporation (USA) Graver Water Systems, Inc. (USA) DMT – Deutshe Montan Technologie GMBH (Germany) Bender Corporation, Inc. (USA) PALL (USA) LURGI (Germany)

6. Typical lay-out of an ESP Electrostatic Precipitator

7. Dedusting system – Piping lines and ESPs Distribution pipes; 3 series of ESPs; exit plenum 3D built with AutoCAD/Inventor Red surfaces: baffles and walls Blue surfaces: interior for flux control Green surfaces: perforated plates Computational reasons: ESPs had to be simulated apart

8. Computational domain – ESP #2 Inlet perforated plates: plate1in plate2in plate3in Inlet flange Hopper baffles Outlet plates Exit flange

9. Computational domain – Collecting plates

10. ESP mesh Gambit –Fluent Ansys Hybrid mesh; Total of 1.5Mi elements Elements of: 60mm between collecting plates, 300mm for the rest of the domain.

13. Contours of velocity magnitude in y = 0.15 Boundary conditions are taken from the system, and uploaded at inlet flange through profile rotation and translation

14. Contours of velocity magnitude in y = 0.45m

15. Contours of velocity magnitude in y = 0.75m

16. Contours of velocity magnitude in y = 1.05m

17. Contours of velocity magnitude in z = 0m

18. Rotation and translation of the velocity profile read from the dedusting system resulted in a nearly uniform velocity profile at ESP’s inlet;

19. The solution was to rotate and translate the ESP’s geometry and mesh in Gambit to coincide the inlet flange with the position of the written profile.

20. Contours of velocity magnitude in y = 0.15 Boundary conditions are taken from the system, with prior translation and rotation of ESP’s geometry in Gambit

21. Contours of velocity magnitude in y = 0.45m

22. Contours of velocity magnitude in y = 0.75m

23. Contours of velocity magnitude in y = 1.05m

24. Contours of velocity magnitude in z = 0m

25. Perforated plates Assumed as porous media, with pressure loss  Re calculated by:

26. Contours of velocity magnitude for the first perforated plate at inlet (plate_1in)

27. Contours of velocity magnitude for the second perforated plate at inlet (plate_2in)

28. Movie Contours of velocity magnitude for the third perforated plate at inlet (plate_3in)

29. Final remarks The efficiency of an electrostatic precipitator is strongly dependent on the velocity profile: optimizing the gas flow distribution improves the dedusting process; The profile assumed at ESP inlet changes the gas distribution inside the collecting chamber, leading to misinterpretations of flow behaviour; The porous jump boundary condition for the perforated plates has demonstrated to be feasible once the actual simulation of the holes is possible but too expensive in terms of computer time; A successful optimization work was conducted afterwards in order to reach a more homogenous velocity profile within the ESP, and therefore to reduce the particulate emission.

31. SEDE Enfil Engenharia & Serviços Ltda Avenida Brigadeiro Faria Lima, 1912 – 7 º andar Edifício Cal Center II Cep: 01451-907 Pinheiros – São Paulo – SP Brasil Telefone: 55 11 3093-2727 FILIAL Enfil Engenharia & Serviços Ltda Avenida Nossa Senhora da Saúde, 381. Cep: 29161-030 Carapina – Serra / ES - Brasil Telefone: 55 27 3205-2727 E-mail: enfil_servicos@enfil.com.br