DESIGN AND CONSTRUCTION OF A PCI RIG FOR EVALUATION OF PULVERIZED FUELS COMBUSTION: EQUIPMENT FEATURES

René Lúcio Rech,Nilson Romeu Marcílio,Antônio César Faria Vilela,Eduardo Osório,Janaina G M S Machado,Claudia Caroline Teixeira Barbieri,Maurício Covcevich Bagatini,Antônio Eduardo Clark Peres,André Da Silveira Machado,Juliana Gonçalves Pohlmann

doi:10.4322/2176-1523.20181507

René Lúcio Rech, Nilson Romeu Marcílio + Show 8 more

Open Access

https://doi.org/10.4322/2176-1523.20181507

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Abstract

Pulverized coal injection (PCI) is a technique worldwide used in blast furnaces (BFs) to reduce coke consumption. Burning of pulverized coal injected into tuyeres of BFs takes place under medium pressure (up to 450 kPa), high flame temperatures (around 2500 K), very fast heating rates (105 â106 K/s) and very short residence times, less than 40 ms. Since there are no standard tests for evaluation of coal combustibility at PCI conditions, lab scale injection rigs are usually employed for this purpose. This work shows relevant characteristics of the injection rig developed by LASID-UFRGS, which operates at automated injection mode. The main rig features are direct measurement of pressure and temperature inside the combustion zone during combustion process, temperature measurement with ultra-fast thermocouples (ms), high speed control and data acquisition (ms) and collection of both solid and gaseous combustion products. First results showed pressure and temperature evolution along throughout the combustion test, with and without sample, combustion gas composition and coal burnout for different coals. Experimental data statistics showed good repeatability for all tested coals.

Highlights

Pulverized coal injection (PCI) is a technology widely used in blast furnaces (BFs)
PCI rates have increased in most BFs, reaching values between 150 – 220 kg/t hot metal [1,2]
This paper aims to present the injection rig developed at the Iron and Steelmaking Laboratory of the Federal University of Rio Grande do Sul, Brazil (LASID-UFRGS), as well as its possibilities and some kinetic and thermodynamic aspects of the tests to be developed in this equipment

Summary

Introduction

Pulverized coal injection (PCI) is a technology widely used in blast furnaces (BFs). PCI is effective both in reducing the consumption of coke, which is directly linked to the cost reduction of produced hot metal, as in increasing productivity in BFs. Despite the recognized economic and environmental advantages of PCI, some coal-related technical difficulties may limit the level of coke substitution such as generation of char, which is residual solid with unburned carbon, soot and tar during the fast pyrolysis and combustion of coal injected [3]. Fine char particles carried by the ascending exhaust gases at high PCI rates may accumulate along the BF, leading to a decrease of bed permeability and unstable operation, as well as undesirable gas and temperature distribution and possible hanging of the burden [3,4]. The aim of the PCI operation is always to keep the amount of unburned carbon in char in the BF stack at a low level while increasing the PCI rate [3]

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