Cinética da gaseificação com CO2 de resíduos sólidos da indústria alimentícia

• Autor(a) principal: Gabriel, Isabel Alves Pimenta
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/123456789/25992
• topic: Biomassa; Resíduos sólidos; Conversão térmica; Termogravimetria; Cinética; Biomass; Solid waste; Thermal conversion; Thermogravimetry; Kinetics; CNPQ::ENGENHARIAS

The thermochemical conversion of biomass is a means of disposal and use of solid waste, mainly from agro-industries. The objective of this study was to analyze the gasification characteristics of residues from coffee grounds (BC), guava seed (SG) and cashew bagasse (BCJ) in N2 (pyrolysis) and CO2 (gasification) atmospheres, in addition to observing the kinetics of the process. The materials went through the process of pyrolysis followed by gasification in a continuous way, without the need to remove the material after being pyrolyzed. Gasification was studied in isothermal and dynamic mode. For the analysis of gasification in the isothermal mode, the material was heated in an inert atmosphere of N2 with a heating rate of 20 ºC/min and a flow of 100 mL/min until reaching the temperature of 875, 925 and 975 ºC at which, after this temperature, CO2 gas was activated. In the dynamic process (non-isothermal), the gasifying agent (CO2) was activated from the beginning of the reaction (room temperature) until reaching a temperature of 1000 °C, with a constant flow of 100 mL/min and heating rates varying between (10, 20, 30 and 40°C/min). In the pyrolysis process, the materials from temperatures close to 600 ºC began to decompose slowly, whereas in the CO2 atmosphere the mass loss profile was very close to pyrolysis below 600 ºC. At higher temperatures, the materials continued to react until the complete carbon consumption of the biochar. The analyzed biomasses showed a high calorific value when compared to other biomasses found in the literature ranging between (19.2 and 22.7 MJ.kg-1). The content of volatile materials and fixed carbon showed that there is a large amount of compounds to be devolatilized and there is little ash production, mainly for SG and BCJ. To analyze the kinetics, the models were applied: homogeneous, unreacted core and random pores for the three analyzed biomasses. In the non-isothermal kinetics, the activation energy varied between 155.18 - 205.41 kJ.mol-1 and the pre-exponential factor between 9.94x105 - 6.49x108 min-1. The activation energies for the isothermal method ranged between 123.55 - 219.22 kJ.mol-1 and the pre-exponential factor between 2.99x105 - 2.62x108 min-1. In this way, it is possible to verify that biomasses have good physicochemical characteristics and that their applicability for energy purposes is possible, in addition to being a more suitable use for waste.