CZ.1.07/2.3.00/

Transcription

1 NEW CREATIVE TEAMS IN PRIORITIES OF SCIENTIFIC RESEARCH CZ.1.07/2.3.00/ This project is funded by Structural Funds of the European Union (ESF) and state budget of the Czech Republic

2 Theme: Experimental examination of coal conversion in shaft furnaces This project is funded by Structural Funds of the European Union (ESF) and state budget of the Czech Republic

3 Experimental examination of coal conversion in shaft furnaces H. T. Ho,, A. Babich, D. Senk

4 Content Introduction to shaft furnaces Coal injection in BF Examination of coal conversion at the Dept. of Ferrous Metallurgy (IEHK), RWTH Aachen University Summary

5 Introduction to shaft furnaces Shaft Furnaces Characteristic use of counter flow principle Examples of shaft furnaces in steel sector: Midrex Corex Cupola furnace Blast furnace Midrex COREX Cupola Flow of solid matter Gas flow 1

6 Introduction to shaft furnaces Blast Furnace (BF) Shaft furnace which continiously operates based on the counter flow principle Input: Iron ore, pellets and sinter Iron carrier Coke, pulverized coals Carbon carrier Output: Pig Iron 4 5 wt.% C Slag Binding of unwanted elements of ores and coals Throat Armor and Staves Staves and Plate Coolers Hot Blast Fuel Injection Carbon Hearth Top Shaft Belly Bosh Hearth Blast Furnace Bell-less Top System Free-Standing Access Tower Profile Meter Sub-Burden Probe Production: t/d Diameter Top: m Belly: m Heart: m Inner Vol.: m³ Height: m 2

7 Introduction to shaft furnaces Main Processes in BF Coke reacts with oxygen CO production based on boudouard-reaction Carbon monoxide is used for reduction of iron oxides Reaction of coke produces the heat needed for this process C + O 2 CO 2 H 0 < 0 C + CO 2 2CO H 0 > 0 3 Fe 2 O 3 + CO 2 Fe 3 O 4 + CO 2 ΔH 0 < 0 Fe 3 O 4 + CO 3 FeO + CO 2 ΔH 0 > 0 FeO + CO Fe + CO 2 ΔH 0 < 0 Specific coke consumption can be decreased by utilization of auxiliary reducing agents 3

8 Coal Injection in BF Fuel Injection Use of auxiliary reducing agents Decrease of specific coke consumption Increase of BF performance Different kinds of auxiliary reducing agents Pulverised Coal kg/t HM Oil kg/t HM Natural Gas m 3 /t HM Plastics ~40 kg/t HM ; Iron ore, coke and limestone Hot waste gas 400 C 1200 C Hot air blast Tap hole for pig iron and slag 4

9 Examination of coal conversion at the Dept. of Ferrous Metallurgy Simulation of injection into the raceway Calculation methods for of conversion degree Based on offgas analysis η Gas = 100 CO 2 + CO + CH 4 φ CO2 Based on ash content of sample and residues η ash = 1 x ash,coal x ash,residue Based on ash and carbon content of sample and residues η c = 1 x ash,coal x ash,residue x C,residue x C,coal η Gas conversion degree based on offgas η ash conversion degree based on ash analysis, η C conversion degree based on ash and carbon content CH 4 methane content in offgas [vol-%] CO 2 carbon dioxide content in offgas [vol-%], CO carbon monoxide in offgas [vol-%] φ CO2 theoretical maximum amount of CO 2 produced x C,coal carbon content before conversion [wt. %] x C,residue carbon content after conversion [wt. %] x ash,coal ash content before conversion [wt. %] x ash,res ash content after conversion [wt. %] 5

10 Conversion degreee [%] sub-stoichiometric area Examination of coal conversion at the Dept. of Ferrous Metallurgy Simulation of injection in raceway Batch Injection Rig Determination of conversion behaviour for different O/C atomic ratios Use of various amounts of coal at a contant atmosphere Czech coal 1 Coal High pressure O 2 Nitrogen Preheating furnace Induction furnace Different O/C atomic ratios Czech coal 2 Filter Gas sampling bottle O/C atomic ratio 6

11 Ofen 2 Examination of coal conversion at the Dept. of Ferrous Metallurgy Simulation of injection in raceway Multifunctional Injection Rig for ironmaking (MIRI) Determination of coals conversion degree at Different injection rates Gas compostion Temperature Conditions similar to blast furnace O 2 MFC N 2 Ar CO CO 2 P-24 Feeder Dosierer Furnace Ofen 1 1 Thermocouple t Furnace 2 Filter Filter Thermo -couple t Collection of unburned residues (char) 7

12 Examination of coal conversion at the Dept. of Ferrous Metallurgy Simulation of injection in raceway Coke Bed Simulator (COBESI) Examination of interaction of auxiliary reducing agents with coke Temperature profiling during injection Probe sampling at different positions 2400 C 1900 C 1400 C 8

13 Heat flux in mw Change of mass in % Examination of coals conversion at the Dept. of Ferrous Metallurgy Determination of kinetic data of solid fuels Micro balance DTA, TG and DSC analysis at different temperature and atmospheric conditions Determination of phase transformation reaction range and duration time in s*10³

14 TG in % Temperatur in C Examination of coal conversion at the Dept. of Ferrous Metallurgy Determination of kinetic data of solid fuels Tammann Furnace Examination of conversion behaviour under isothermal conditions Reaction of coals under thermal shock and flash pyrolysis Simulation of reactions at certain temperatures Drying and primary pyrolysis Coals and coal briquettes Secondary pyrolysis Gasification with CO Zeit in h 0 10

15 Examination of coal conversion at the Dept. of Ferrous Metallurgy Investigation of microstructure LOM Quantitative and qualitative analysis of coals as well as residues Change of size und form based on comparision before and after conversion SEM Qualitative examination of surface and geometry of different coal grains Conclusion of conversion behaviour based on change of surface before and after conversion 200 µm 11

16 Summary The Dept. of Ferrous Metallurgy posseses a wide range of facilities and methods to analyse and investigate coal conversion behaviour Possible investigation under conditions for different: Isothermes Atmospheres/ oxygen enrichment O/C atomic ratios Microstructural influence on coal conversion can be investigated 12

17 Thank you for your attention Contact Hai Thong Ho Department of Ferrous Metallurgy (IEHK) Chair for Metallurgy of Iron and Steel RWTH Aachen University - Germany Intzestrasse 1 D Aachen Hai.Thong.Ho@iehk.rwth-aachen.de Dieter.Senk@iehk.rwth-aachen.de Alexander.Babich@iehk.rwth-aachen.de This project is funded by Structural Funds of the European Union and state budget of the Czech Republic