Thermal Process Engineering Plastic Particle Injection into Blast

Thermal Process Engineering Plastic Particle Injection into Blast Furnace Raceway K 1 -MET Competence Center for Excellent Technologies in Advanced Metallurgical and Environmental Process Development Area 4 – Valuation and Optimization of Metallurgical Raw Materials CFD Simulation of Co-Injection of Plastic Particles and Oil into a Blast Furnace Raceway Christian JORDAN, Christian MAIER, Michael HARASEK Christoph FEILMAYR, Stefan SCHUSTER (voestalpine Stahl, Linz) michael. harasek@tuwien. ac. at Achema 2012 Institute of Chemical Engineering page 1

Thermal Process Engineering Plastic Particle Injection into Blast Furnace Raceway n Optimization of the operation conditions and maximization of plastics injection rate l l l n n n (voestalpine Stahl Gmb. H, Linz) Detailed CFD-modeling of the blast furnace raceway Determination of fluid dynamic properties Investigations of the reaction kinetics of different auxiliary reductants Maximum plastic injection capacity 220. 000 t/a Startup in June 2007 (test operation since 2006) Input material processed waste plastics l l n Blast Furnace HO A Pellets, agglomerates from mixed plastics fractions (municipal and industrial waste) Granulate from shredder residue treatment process Region observed Flexibility in injection Pellets, agglomerates and granulate Achema 2012 Institute of Chemical Engineering page 2

Thermal Process Engineering Plastic Particle Injection into Blast Furnace Raceway n Turbulence l n Radiation l l n Global and heterogeneous reactions (9 gas-phase species, coke) Eddy Dissipation Concept (Magnussen) DPM – Discrete Particle Model l n Discrete Ordinates Model (DOM) Absorption coefficients estimated with the „Weighted Sum of Grey Gases“ (WSGG)-approach Reaction l l n SST-kω-Model by Menter or realizable ke-Model Lagrangian particle tracking, coupled to fluid phase via source terms Plastic particles – radiation interaction + decomposition Heavy fuel oil multicomponent droplets - pyrolysis UDF – User Defined Functions to extend CFD code l l l Raceway formation and coke bed porosity Extended radiation model Particle treatment (reaction, impact on raceway) Achema 2012 Institute of Chemical Engineering page 3

Thermal Process Engineering Plastic Particle Injection into Blast Furnace Raceway § Measurements l l Construction of a small scale model of the oil lance and the tuyere based on Reynolds analogy Droplet velocity (PIV) Gas velocity (LDA with seeding or PIV with fluorescent tracer) Droplet size distribution using high speed photographs PIV image of the jet (velocity vectors with geometry in background) detailed view of the outlet Achema 2012 Institute of Chemical Engineering page 4

Thermal Process Engineering Plastic Particle Injection into Blast Furnace Raceway § Results of CFD Modeling Surface in tuyére level – mass fraction of carbon dioxide Flow direction Raceway shape (50% porosity, blue) and hot blast pathlines entering from bustle pipe (colored according to velocity magnitude in m/s) Achema 2012 Mole fraction CO in the symmetry plane Institute of Chemical Engineering page 5

Thermal Process Engineering Plastic Particle Injection into Blast Furnace Raceway § CFD Model Development l l l Heat transfer due to convection, thermal velocity magnitude with path lines conductivity and radiation [mm/s] coke bed Effects of material properties of fluid phase 2. 5 Solid phase material properties & porosity 2. 0 Coupling without using Eulerian model 1. 5 Implementation of heterogenous reactions 1. 0 (coke bed – surrounding gas phase) Validation of the new method using 0. 5 systems of various complexity 0 [m/s] 20 gas flow 16 12 8 4 0 Achema 2012 Institute of Chemical Engineering page 6

Thermal Process Engineering Plastic Particle Injection into Blast Furnace Raceway Summary n n n Measurement (PIV) and modeling of fuel oil droplet size distribution Characterization of the pyrolysis of waste plastic particles Implementation of new modeling approach: Dual Grid Successful validation of CFD-model by comparison with experimental data Implementation of UDF in full-scale blast furnace Further Work Further development of the Dual Grid Method - CFD-Calculations for different operating conditions n Co-injection of particles and fuel oil n Additional high speed imaging for validation of spray modeling n Achema 2012 Institute of Chemical Engineering page 7