CETAS Inline scrap control for EAF charging. Authors: C. Fricke-Begemann 1, M. Brunk 2, V. Sturm 1, R. Noll 1 U. Chiarotti 3, V.

Transcription

1 Title: Abstract No. 41 Inline scrap control for EAF charging Authors: C. Fricke-Begemann 1, M. Brunk 2, V. Sturm 1, R. Noll 1 U. Chiarotti 3, V. Volponi 4 Company/ Institute: Presentation Abstract: 1 Fraunhofer Institute for Laser Technology ILT, Aachen (DE), 2 RWTH Aachen University (DE), 3 CSM (IT), 4 Ori Martin (IT) Oral presentation The inline acquisition of the chemical composition of the scrap feed provides valuable information to optimize EAF production efficiency. In contrast to model based charging procedures, especially the determination of the amount of alloying elements such as silicon and manganese which have already been loaded into the furnace would allow to control the further charging in real-time and regulate the total analyte mass balance. At the ConSteel plant of Ori Martin using a conveyor charging system instead of the more common basket-loading the accessibility of the continuous scrap mass flow offers the possibility for direct inline analysis of the scrap composition during the process. For the analysis over distances of more than one meter, an all-optical laser-based method was chosen. Combining laser-shape detection and laser-spectroscopy, both the composition and the local filling height of the conveyor are determined with a time resolution of a few seconds. Within a joint R&D project supported by the RFCS a test installation was realized and the approach was evaluated. Contact Address: Fraunhofer ILT, Steinbachstr. 15, Aachen, Germany + 49 (0) cord.fricke-begemann@ilt.fraunhofer.de

2 Inline Scrap Control for EAF Charging 2015 C. Fricke-Begemann 1, M. Brunk 2, V. Sturm 1, R. Noll 1 U. Chiarotti 3, V. Volponi 4 1 Fraunhofer Institute for Laser Technology ILT, Aachen, 2 RWTH Aachen University, 3 CSM, 4 Ori Martin Düsseldorf, Scrap quality management for EAF steelmaking Options for steelmakers Trust your supplier Check shipment samples regularly Monitor composition and mix qualities Sort at your own premises 2 1

3 Scrap quality management for EAF steelmaking Options for steelmakers Trust your supplier Check shipment samples regularly Monitor composition and mix qualities Sort at your own premises Inline analysis and control of scrap charging Concept Use laser analyser to determine the average scrap composition Monitor composition during charging process Control composition of heats by adjusting charging mix Apply to a continuous charging process RFCS project IPRO, Inline elemental characterisation of scrap charging for improved EAF charging control and internal scrap recycling Fraunhofer ILT, Swerea KIMAB, Centro Sviluppo Materiali, O.R.I. Martin, Outokumpu Stainless AB, RWTH Aachen University 3 4 2

4 20 15 Steel recycling: laser characterisation of shredder scrap LIBS module Laser direct analysis using LIBS is known to determine scrap composition in spite of material contaminations high measurement rate provides average for inhomogeneous materials operate inline at conveyor belt under industrial conditions Challenge: determine the elemental mass balance of Consteel EAF charging 5 TA S Inline scrap monitoring by LIBS cranes charging area CE pig iron dynamic seal dispenser tunnel EAF steel casting conveyor structure Position for scrap monitoring by LIBS, approx. 25 m from EAF Consteel installation at OriMartin slag casting 6 3

5 20 15 LIBS at scrap fraction C with added high Si scrap 5 Si mass fraction by LIBS, moving average of 200 values C fraction with high Si scrap added (heat 1452) Si mass fraction [m.-%], LIBS 4 1 min Pulse number measurement campaign at ORI Martin 7 TA S Improved charging procedure control system CE scrap deposit with different grades of steel scrap blend scrap grades to optimize charge composition for each heat guidance for crane operators from inline measurements 8 4

6 Data evaluation of ICPC at Ori Martin material addition tracking production program scrap analysis IPRO_server conveyor (scrap flow) DB IPRO IPRO_cranes IPRO_control _room OWS OWS Calibration of laser analyser for low alloyed steel element Si required* Si achieved Ni achieved Mo achieved c max [m.-%] accuracy s x,0 [m.-%] Calibration under plant conditions Working distance 1.2 m (usage: m) Measurement time per sample 7 s *) requirements defined by Ori Martin for ICPC, not specified for Ni and Mo

7 Measurement data of laser analyser laser measurement scrap height profile co-located with LIBS analysis plant estimation of current scrap velocity on pendulum conveyor v(t) volume mass flow on conveyor: V(t) = h(t) * d * v(t) plant measurement of mass change in EAF: M(t) average density of each scrap grade j: = < M / V(t) > j mean height h(t) d height profile of scrap measured by light section h(t,y) Estimation of elemental charge in the furnace current flow per element: c El (t) * V(t) mass at analyser position: M El (t)= c El (t) * V(t) * example of two subsequent heats on February 20 th Heat AJ1240 AJ1241 M(Si) inline 195 kg 347 kg SiO 2 in slag 5.5 % 7.6 % campaign with > 200 heats, not always good correlation 12 6

8 Estimation of elemental charge in the furnace 2 approaches for the accumulated elemental mass per heat M El = S DM El (t) summed over time steps of Dt = 5 to 10 s 1. from laser analyser only: DM El (t+t del ) = c El (t) * * V(t) with V(t) = h(t) * d * v(t) * Dt = < S DM /S V(t) > j Scrap charging area electro-magnetic engine 2. using total mass increment DM(t) in EAF also: DM El (t+t del ) = c El (t) * DM (t+t del ) Conclusions v(t) j scrap class = laser = works laser analyser pendulum velocity c El (t) h(t) Pendulum Conveyor mean height h(t) d t del Scrap velocity EAF M(t) height profile of scrap measured by light section h(t,y) Inline analysis of scrap on pendulum conveyor in Consteel plant demonstrated Integration of laser analyser in EAF plant for improved charging control Related parameter measurements required inline for accurate mass balance closure Individual implementation concepts to be worked out according to scrap handling at plant