ABSTRACT
This study assessed the effects of adding plastics and waste vegetable oil on the quality of coke in the coking process, on a pilot scale. A typical composition of the main plastics found in municipal solid waste was prepared using 33% HDPE, 5% LDPE, 10% PP, 21% PET, 24.8% PS, 5.2% PVC, 1% cellulose and also a 0.5% waste vegetable oil was added. The wastes were added to the coal blends in the proportions of 1%, 2% and 3% for plastics and 0.5% for vegetable oil. Two types of experiments were performed. The first was carried out in a hearth heating furnace (HHF) at temperatures of up to 900°C for a 7 h period. The second was a box test, which consists of heating coal blends in 18L cans using a pilot coking oven, for approximately 20 h at temperatures between 1050 and 1100°C. The quality parameters used for the assessment were the CSR (coke strength after reaction), CRI (coke reactivity index), ash, volatile matter and sulfur in order to identify the effect of plastic and vegetable oil on coke quality. Results for CSR in the HHF averaged 52.3%, and 56.63% in box test trials. The CRI results ranged from 26.6% to 35.7%. Among the different percentages of plastics used, 3% plastic blends provided the most stable CSR results. The industrial furnaces work at temperatures between 1100 and 1350°C and time coking 21-24h, compared to the test conditions achieved in the HHF and pilot furnace with box test. It was concluded that the results of CSR and CRI are consistent with the tests confirming the feasibility of using plastic in the steelmaking process.
Subject(s)
Metallurgy/methods , Plant Oils , Plastics , Recycling/methods , Brazil , Coal/analysis , Cooking , Hot Temperature , Metallurgy/economics , Pilot Projects , Solid Waste , SteelABSTRACT
O presente trabalho apresenta a avaliação técnica e ambiental de uma planta piloto de tratamento de Resíduos de Serviços de Saúde (RSS) por pirólise quanto à produtividade, ao consumo de combustível, ao rendimento gravimétrico do processo, às emissões atmosféricas, aos efluentes líquidos e ao produto carbonizado obtido. O processo apresentou valores para perda de massa entre 46,75 e 58,77%, para tempos de processamento variando entre 2 e 6 horas. A tecnologia empregada demonstrou maior segurança ambiental na terceira condição de operação testada, em relação às emissões de contaminantes para a atmosfera, levando-se em consideração o valor obtido na concentração de dioxinas e furanos de 0,0162 ng/Nm3. Nessa condição, a operação ocorreu com dois combustores, gás de pirólise sendo injetado no duto de alimentação de biomassa e com incremento de 15% no volume do fluxo de ar na zona de combustão dos cavacos, em mistura com o gás de pirólise. A solução proposta apresentou potencial para ser aplicada em municípios que enfrentam o gerenciamento adequado dos RSS como um desafio a ser transposto.
This work shows the technical and environmental evaluation of a pilot plant for treatment of health waste by pyrolysis, regarding its productivity, fuel consumption, weight loss in the process, atmospheric emissions, wastewater and the charcoal obtained. The process resulted in values of weight loss between 46,75 and 58,77%, for processing time ranged between 2 and 6 hours. The greatest environmental safety was obtained in the third tested operation condition, concerning atmospheric emissions of pollutants, as the concentration of dioxins and furans value obtained was 0,0162ng/Nm3. Two combustors were used in the operation, pyrolysis gas was injected in the biomass feed pipe, and the air flow volume was increased by 15% in the combustion zone of the wood chips, mixed with the pyrolysis gas. The proposed solution has shown great potential to be used in municipalities dealing with proper management of health waste as a challenge to be overcome.