Efeito da adição de coque verde de petróleo na microestrutura e características metalúrgicas do coque

Abstract

The challenge in coke production is related to the preparation of cost-effective coal blends and to produce coke with the proper quality for use in blast furnaces. In this work the influence of the addition of green petroleum coke (CVP) to the coking mixtures on the microtexture formation and metallurgical quality of the coke was evaluated. Tests of rheological and petrographic characterization of the coals and other materials were carried out, besides the evaluation of the metallurgical quality of the coke produced with additions of up to 40% CVP in the mixture. The cokes were produced using an industrial mix as a base in a resistive pilot kiln. For the evaluation of the coke quality, tests of DI15-150, CRI, CSR, mercury porosimetry and X-ray diffraction (crystallite size) and coke texture analysis were performed before and after the CO2 reactivity test (CRI ). The test performed with the formulation of a binary mixture containing American volatile medium carbon and CVP showed a great correlation with the fluidity of the mixture. For the cokes obtained, it was observed that the coal mixture was able to satisfactorily absorb up to 30% CVP, forming a quality coke (DI, CRI and CSR) similar to the industrial mixture. The use of CVP above 30% led to a sudden deterioration in the quality of the coke. The main textural components observed were: mosaic, fragmentary, fusite, anisotropic inert and CVP. In general, prior to the CRI test, the cokes showed good cohesion, with the carbonaceous matrix absorbing the CVP. After the reaction with CO2, the preferential consumption of fusible, fragmentary and anisotropic inert textures was verified due to the Boudouard reaction, besides the deterioration of the interfaces between the carbonaceous matrix and the CVP. In addition, the results have shown that the increase of the mosaic structure contributes to the increase of DI15-150 and CSR. The other textural components were less determinant in relation to the quality of the coke.