Análise termodinâmica do processo de pirólise de microalga a partir do cálculo de equilíbrio químico e de fases simultâneo

• Autor(a) principal: Viegas, Júnnio de Sousa
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/12753
• topic: Microalga; Pirólise; Equilíbrio químico e de fases; Minimização de Gibbs; Otimização; Microalgae; Pyrolysis; Chemical and phase equilibrium; Gibbs minimization; Optimization; OUTROS

In a scenario where population growth is exponential, the supply of the energy matrix is finite, the processing and use of current sources are extremely harmful to the environment, a new name is pointed out as a sustainable energy source to supply all these issues: microalgae biomass. This is particularly interesting due to its high growth rate, high productivity, adaptability to different habitats, non-competitiveness with agriculture and the results of its processing can be used to produce biofuels, products of high added value of industrial interest, treatment and soil recovery. In addition, we may subject it to a decomposition process to obtain your products (bio-oil, gas and charcoal). In addition, it can be subjected to a decomposition process to obtain its products (bio-oil, gas and charcoal). In this study, a thermodynamic analysis of the pyrolysis of microalgae biomass was carried out, which consists of processing the biomass at high temperatures in the absence or low presence of oxygen. From this work, data were obtained that represent the behavior of the reaction system in chemical and phase equilibrium for different operating conditions, varying temperature and humidity, in which the conditions in which the required products are found in greater and/or less quantities. The method for calculating the chemical and phase simultaneous equilibrium explored was Gibbs minimization, under constant temperature and pressure conditions, by a non-stoichiometric approach. A mixture-model composed of palmitic acid, glucose and glutamic acid was considered to represent the biomass of microalgae. The possibility of forming a liquid phase, simulated by the UNIFAC thermodynamic model, was investigated, using the stochastic particle swarm optimization method, in which the possibility of forming 3 distinct phases was considered, one phase behaving as a mixture of ideal gases, a liquid phase and another solid phase modeled as pure solid carbon. The minimization model was also implemented in the GAMS® software, General Algebraic Modeling System, using the CONOPT non-linear programming solver, in which only formation of solid and gaseous products was considered. The studied pyrolysis reaction was predominantly exothermic, with heat of reaction varying from approximately -32 to -16 kJ/mol. For the studied conditions, there was no prediction of liquid phase in the reaction system. Gaseous products such as H2 and CO2 showed maximum yield, 0.246 and 0.415 mol per mol of carbon fed respectively, both under maximum operating conditions for humidity and temperature, under the same conditions there was a greater potential for thermal energy generation, evaluated by the total heating value.