INJECTION IN SIDERURGIC FURNACES

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22 Φεβ 2014 (πριν από 3 χρόνια και 3 μήνες)

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Ischia, 24
-
27 June 2007

ANALYSIS OF MULTIPHASE REACTING
TURBULENT JETS: CASE STUDY ON CARBON
INJECTION IN SIDERURGIC FURNACES

1
Centro Interdipartimentale di Fluidodinamica e Idraulica &


2
Dipartimento di Energetica e Macchine, Università di Udine

3
Dip. Ingegneria Chimica, Chimica Industriale e Scienza dei Materiali, Universitò di Pisa

M. Campolo
1
, M. Andreoli
1
, L. Tognotti
3
, A. Soldati
1,2


IcheaP
-
8

The eight International Conference on Chemical & Process Engineering

A successful story?

Targets of injection & Industrial challenge…

1. Heating Scrap (oxy
-
methane lance)

2. Feeding consumables to control
slag/bath composition (carbon injection
system)

Why not a multipurpose injector?

Innovative design of multipurpose injector

Features:

1.
Coherent supersonic
annular oxygen stream

2.
Sonic methane stream

3.
Inner (low velocity)
particle laden flow

Research Objectives

1.
Virtual testing of injector performaces






捡牢潮r楮i散e楯渠祩敬y

2.
Identification of rules for field installations






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捡牢潮r捨c牡捴敲楳i楣猠⡳楺(Ⱐ煵慬楴礩

3.
Identification of guidelines for performance
optimization






mechanisms controlling performances

Modelling challenges…

Supersonic flow O
2

Sonic flow CH
4

Combustion CH
4
/O
2

Transport of C particles

Radiative/Reactive
environment

C Oxydation &
Devolatilization

… and modelling tools

Finite volume solver
Navier
-
Stokes equations

1.
Flow field characterization

2.
Basic characterization of
chemico
-
thermal
environment

Lagrangian tracking

1.
characterization of
chemico
-
thermal
environment seen by
carbon particles

Reactor Network Analysis

1.
Precise modeling of
oxidation/devolatilization

2.
Evaluation of injection
performances

Numerical details
-
1

o
Flow solver: StarCD (FV)

o
Boundary conditions:


fixed mass flow rate (O
2
, CH
4
, Air, Air extraction)


temperature & emissivity profiles (electrodes, slag & wall)

o
Turbulence model:


Modified k
-
ε

(+ compressibility effect
-

Sarkar et al. 1991)

o
Combustion model:

CH
4
+1.5 O
2


CO+2H
2
O

CO+0.5 O
2




2

Numerical details
-
2

o
Lagrangian tracking


One way coupling, drag + inertia forces


Non spherical shape (Crowe, 1998)


Eddy interaction model (Gosmann & Ioannides, 1983, Graham, 1998)

o
Reactor Network Analysis:


Gas phase reaction (Ranzi et al.,2001, Falcitelli et al., 2002)


Heterogeneous reaction


Char oxidation


Char devolatilization

Flow field

Temperature field

Lagrangian tracking: radial dispersion

Traditional
configuration

Innovative
configuration

Particle thermo
-
chemical history

Most critical conditions for RNA

Results from RNA

Most critical conditions for RNA

0.09%

0.11%

0.02%

0.03%

Very high injection efficiency is obtained


for large injection distances (L2=1300 mm from slag)


For all commercial types of carbon

Industrial results: field tests

(Duferco La Luvriere S.A.)

Quality/metallurgical results

Traditional
Injector

Hi
-
jet injector

Production
yield

92%

94%

Larger

Productivity

Ferrum
content in
slag

28%

22%

Lower

Waste

Metallic
charge
composition

86% scrap,
14% pig iron

96% scrap,
4% pig iron

Lower

Raw Material

Costs

Yes!