(p27) Integrated modelling of CFD and Thermodynamics for prediction of organic emissions during pre-heating of magnesia-carbon bricks

摘要

Magnesia carbon bricks are commonly used inBOFs and are generally pre-heated before theBOF goes into service. Owing to very stringentemission regulations, the BOF pre-heatingprocess need to be controlled and optimized sothat, the emission standards are met. One of themajor concerns in organic emissions are itsstringent limits on emission rates and totalvolatile emissions. In the present work, anattempt has been made to integrate CFD andThermodynamic models to predict the emissionrate of volatile organics during the pre-heatingprocess. A one dimensional heat transfer modelwas developed using visual basic and thenintegrated with thermodynamics calculationsusing FactSage 6.4 [1]. The parameters thataffected organic emissions were the pre-heatingprocedure, gas composition of the burner,heating rate and type of the burner. Typicalcomposition of MgO-C bricks and bindermaterials were obtained from literature andvendor data sheets. Chemical reactionsbetween organic materials, refractory and burnergasses were considered. The model predictionsindicated that certain burner conditions coulddestroy all organics before it exits the vesselwhile other conditions needed the use of an afterburner at the mouth of the vessel. The modelwas also able to predict the organic emissionrates based on the chosen pre-heating profile.This kind of predictive model will be very usefulfor the steel industry and enable them to justifypermit limit applications and stick to the limits byfine tuning their pre-heating process.