Navegando por CNPq "CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA::TECNOLOGIA QUIMICA::TRATAMENTOS E APROVEITAMENTO DE REJEITOS"

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Acesso aberto (Open Access)
Estudo do processo de produção de bio-combustíveis via pirólise de resíduos de pneus
(Universidade Federal do Pará, 2019-10-24) SANTOS, Wenderson Gomes dos; DUVOISIN JÚNIOR, Sérgio; http://lattes.cnpq.br/1737235899259374; MACHADO, Nélio Teixeira; http://lattes.cnpq.br/5698208558551065
In this study, the pyrolysis process of waste tires was analyzed in the laboratory and pilot scales. In the lower scale, the temperature variation, the type of catalyst commercially obtained (CaCO3, Na2CO3 and Ca(OH)2), the type of catalyst synthesized / treated from industrial waste (LV 1M HCl, LV 2M HCl and zeolite of kaolin) and the concentration of the NaOH solution impregnated into the tire (0.5, 1 and 2M) in the yields and compositions of the tire pyrolysis oil (TPO). In the larger scale, the evolution of the physicochemical and compositional properties of the TPO’s during the thermal cracking process (T = 400 °C, T = 450 °C and T = 500 °C) was evaluated in order to obtain a liquid product with characteristics of fossil fuels and / or compounds of high commercial value. The results showed that the yield of the TPO's are influenced by the increase in process temperature, by the type of catalyst and by the chemical treatment in the raw material. Being the process at 500 °C and with kaolin zeolite as the catalyst which most optimized the process for the yield and production of aliphatic compounds in the TPO. The use of catalysts led to the reduction of aromatic compounds and sulfur compounds in the liquid fraction. On the smaller scale, the behavior of the aliphatic compounds in thermocatalytic processes and chemical impregnation of the raw material was strongly influenced by the composition of d-limonene in the oils of pyrolysis of tires. The results of the pilot scale allowed us to conclude that there were variations in the physicochemical and rheological properties during the cracking process, but tend to stabilize in 65 minutes of process, presenting low acidity and low viscosity. The main substances identified throughout the process were d-limonene, BTX (benzene, toluene and xylenes) and cymenes. In the fractionation of TPO’s, the fraction of gasoline (C8 to C10) and kerosene (C8 to C17) are essentially hydrocarbons, while light diesel (C15 to C21) and heavy diesel (C17 to C23) by heteroaromatics. It is also concluded that sulfur and halogen compounds tend to be separated from the light diesel range.
Acesso aberto (Open Access)
Estudo e avaliação do uso de resíduos do processo Bayer como matéria-prima na produção de agregados sintéticos para a construção civil
(Universidade Federal do Pará, 2010-03) SOUZA, José Antônio da Silva; QUARESMA, João Nazareno Nonato; http://lattes.cnpq.br/7826389991864785
The large amount of solid waste coming from mines and metallurgical industries became a serious social-environmental problem. The physical and chemical features of this material can raise a great interest in other industries. The ceramic industry might be a great costumer for most of this material, since it can supply the current lack of raw material. The red mud, main industrial residue of the alumina manufacturing, has been a very interesting input for several kinds of aggregates manufacturing used for the concrete production in civil engineering. In this context, this paper deals with studies concerning the red mud recycling to be applied as raw material for the synthetic light aggregate production to be used as an alternative material in the civil construction industry. This is because of its physical-chemical features and the large amount annually produced (around 10 million tons within two factories in the North of Brazil). The studies completed in this work show the feasibility of aggregates manufacturing, with different properties and possibilities. These properties depend on the parameters control such as content of free silica and clay, and the sintering temperature. Such variables allow to perfectly controlling the glassy phase formation which is responsible for the aggregate properties such as: porosity, mechanical resistance and density. This material can be used for conventional or special concretes to supply the civil engineering needs.