Lack of correlation between the properties of a petroleum coke and its behaviour during combustion

Abstract

This work is an attempt to establish links between the properties of the petcoke that can be measured through standard analysis in the laboratory and the behaviour of the petcoke both in terms of its combustion velocity and the emission of gas pollutants. A large number of petcokes, 22, taken from different sources, were burnt in an Entrained Flow Reactor (EFR) in conditions close to those of a fluidised bed of a cement plant precalciner. The burnout for the 22 petcokes ranged from 68% to 81%. The gas emissions resulting from their combustion were analysed. Prior to this, each type of petcoke was characterised in terms of its chemical composition, volatile matter and ash content, structural properties and LCV. The correlation between all these characteristics and the combustion velocity, SO 2 emissions and NO emissions in the EFR were systematically investigated. The combustion velocity does not appear to be correlated to any of the properties. The emissions of SO 2 can be accurately predicted from the content in S of the petcoke. The emissions in NO are not directly linked to the N content of the petcoke. No simple correlation could be established to predict NO emissions.