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Introduction

Due to the harsh environment of metallurgical processes on-plant measurements are very difficult. Most information about the process is based on classical temperature and pressure measurements. Within this project the process of metals reduction technologies will be investigated in detail to optimize several process steps. 

 

 

Objectives and Motivation

  • Blast furnace fuel substitutes and minimal coke rates
  • Reduction and Refining of Non-Ferrous Metals
  • Online Measurement of Metallization for DRI

Methodology

The commercial systems on the market are not able to resolve inhomogeneity of dense gas solid flows. Electrical Capacitance Tomography (ECT) is a feasible technique to fill this gap and to provide time and space resolved data about the pneumatic conveying of solids. 

Image data from a standard tuyere camera as well as from a high-speed camera can be used to analyse the flame size and dynamics at the lance tip of pulverized coal injection (PCI). Via digital image analysis it should also be possible to implement a particle size estimation of plastic pellets and coke particles. Certain process parameter will be assessed, like temperature zones, coke reactivity and stability, feeding self-reducing agglomerates, injection of fine coal or reducing gas via the tuyeres. The properties of self-reducing agglomerates will be assessed by standard test procedures.

 A mass flow sensor in the PCI or plastic pellets line will be synchronized with the video data from the high-speed camera. The correlation of the signals will give further information on the resolution of the mass flow sensor as well as the optical detection.

The impact of complex recycling materials will be investigated. The reaction behaviour of agglomerates made of complex secondary raw materials will be evaluated thermodynamically and via lab scale test methods. The shaft furnace slag will be reduced in the slag settler furnace. The impact of slag properties is assessed by model calculation and shall be verified by lab- scale tests.

 Furthermore a measuring system to determine the DRI metallization degree will be developed. Different procedures should be analysed regarding their strengths and weaknesses, like x-ray fluorescence analysis, optical and electromagnetic methods.

Results and application

Unsteady mass transport in pipelines for pulverized coal or plastic pellets is responsible for erosion of the pipe system and can have negative effects on blast furnace operation. The obtained results can be used to improve CFD modelling of pneumatic conveying and also provide data to improve the online process control.

The high-speed video data of the tuyere region will allow deeper insight in the flow situation in the raceway area and the gasification behaviour of fuel substitutes, shown in Figure 2.

Current and new alternative reductants, as well as extent of substitution of coarse coke in the shaft furnace process will be evaluated.