Antônio C. F. Vilela

O Simulador da zona de combustão do alto-forno do Laboratório de Siderurgia da UFRGS - uma nova ferramenta na seleção de carvões para injeção

Blast furnace (BF) is the main route for pig iron production. One of the biggest challenges in BF steel industry is the reduction of coke consumption. Cokemaking process employs high cost coals and accounts for the most of polluting gas emissions from integrated steel mills. A successful strategy for saving coke is the injection of auxiliary fuels in tuyere region of BF through PCI (Pulverized Coal Injection) process. Fuel combustion generates energy and reducing gases for iron ore. When injected, coal is subjected to drastic conditions in the raceway of blast furnace: temperatures around 2400 K, heating rates in order of 10 5 to 10 6 K/s and residence times of 10 to 40 ms. Therefore total combustion of coal, especially at high injection rates, is unlikely. It is fundamental to select coals for PCI with good combustibility, thus minimizing the generation of residual solid (char), which can damage the BF operation. There are several types of reactors for the evaluation of coal combustion, such as thermobalances, drop tube furnaces and PCI test rigs. Thermobalances are fixed-bed reactors operating at low heating rates and drop tube furnaces are more suitable for boiler simulation and evaluation of single coals. For operational, strategic and logistical reasons steel mills use coal blends of different characteristics for PCI. Nowadays PCI test rigs are the best option of reactors for evaluation of coals and other fuels for injection. In this context, the Iron and Steelmaking Laboratory of the Federal University of Rio Grande do Sul (LaSid-UFRGS) designed and developed a PCI test rig with innovative features, such as collection of char, quantitative analysis of combustion gases by gas chromatography and acquisition of temperature and pressure data by ultrafast sensors. Unlike the existing models, the equipment is fully automated, being the only one in the country in vertical arrangement, minimizing pressure loss and allowing operation with greater stability. The present work aims to present the characteristics of the LaSid-UFRGS PCI test rig and preliminary experimental results. Key-Words: Ironmaking. Blast furnace. Raceway. Fuels. Pulverized coal. V CONGRESSO BRASILEIRO DE CARVÃO MINERAL CRICIÚMA SC – BRASIL 29 DE MAIO A 01 DE JUNHO DE 2017

AVALIAÇÃO DO EFEITO DA ADIÇÃO DE COQUE DE PETRÓLEO EM TERMOPLASTICIDADE DE MISTURAS DE CARVÕES CONTENDO CARVÃO NACIONAL

Resumo Esse trabalho teve como objetivo avaliar o efeito da adição de diferentes teores de coque verde de petróleo (5, 15 e 30%) nas propriedades termoplásticas de misturas de carvões contendo carvão nacional da camada barro branco. A caracterização termoplástica das misturas foi realizada a partir de testes de plastometria Gieseler e dilatometria AudibertArnu. A caracterização dos carvões mostrou que o carvão nacional possui propriedades termoplásticas muito superiores aos demais carvões. Por consequência, verifica-se que a sua introdução nas misturas causa aumento das propriedades termoplásticas nos testes de plastometria e dilatometria. O coque verde de petróleo, em contrapartida, é um aditivo inerte e atua como um depressor das propriedades termoplásticas. Constatou-se que a adição do coque verde de petróleo às misturas causa redução da fluidez, do intervalo plástico e dilatação nos testes realizados. A sinergia entre do carvão nacional de alta fluidez e o caráter inerte do coque de petróleo mostrou-se vantajoso. Palavras-chave: Termoplasticidade; Carvão Nacional; Coque verde de petróleo; Plastometria Gieseler; Dilatomeria Audibert-Arnu.

Characteristics of Pyrolysis Products from Waste Tyres and Spent Foundry Sand Co-Pyrolysis

The products obtained through thermal conversion of tyres can represent a solution for its disposal which has been considered an environmental problem. In the foundry industry two types of sand are generated: core sand (CS) and green sand (GS); CS is classified as hazardous waste. In this paper two kinds of industrial wastes were approached, in order to propose a solution through co-pyrolysis. The experiments were performed in a bubbling fluidized bed reactor. The oil, fuel gas and char obtained were characterized. The main components present in the oil were naphthalene and anthracene. Char morphology was assessed by Scanning Electron Microscopy, confirming the resin absence on its surface. Isothermal adsorption and desorption indicated that the char obtained from tyre pyrolysis with lower particles has higher superficial area (higher than 200 m2·g−1). The main compounds identified in fuel gas were hydrogen, carbon monoxide, carbon dioxide and hydrocarbons up to 5 carbons.