Modeling and simulation of an isothermal reactor for methanol steam reforming/Modelagem e simulacao de um reator isotermico de reforma a vapor de metanol

Due to growing electricity demand, cheap renewable energy sources are needed. Fuel cells are an interesting alternative for generating electricity since they use hydrogen as their main fuel and release only water and heat to the environment. Although fuel cells show great flexibility in size and operating temperature (some models even operate at low temperatures), the technology has the drawback for hydrogen transportation and storage. However, hydrogen may be produced from methanol steam reforming obtained from renewable sources such as biomass. The use of methanol as raw material in hydrogen production process by steam reforming is highly interesting owing to the fact that alcohol has the best hydrogen [carbon.sup.-1] ratio (4:1) and may be processed at low temperatures and atmospheric pressures. They are features which are desirable for its use in autonomous fuel cells. Current research develops a mathematical model of an isothermal methanol steam reforming reactor and validates it against experimental data from the literature. The mathematical model was solved numerically by MATLAB® and the comparison of its predictions for different experimental conditions indicated that the developed model and the methodology for its numerical solution were adequate. Further, a preliminary analysis was undertaken on methanol steam reforming reactor project for autonomous fuel cell. Keywords: mathematical modelling, methanol, steam reforming, hydrogen. A demanda por energia eletrica e crescente e fontes baratas e renovaveis de energia sao necessarias, com este proposito as celulas a combustivel sao uma alternativa interessante para a geracao de energia eletrica, pois utilizam hidrogenio como principal combustivel e apenas liberam agua e calor ao meio ambiente. As celulas a combustivel apresentam grande flexibilidade quanto ao seu tamanho e tambem quanto a sua temperatura de operacao sendo que alguns modelos operam a baixas temperaturas, porem essa tecnologia esbarra na necessidade de transporte e armazenamento do seu principal combustivel: o hidrogenio. No entanto, o hidrogenio pode ser produzido a partir da reacao de reforma a vapor de metanol, o qual pode ser obtido a partir de fontes renovaveis como a biomassa. A utilizacao do metanol como materia-prima no processo de reforma a vapor para producao de hidrogenio e muito interessante, pois este alcool e o que apresenta a melhor proporcao entre hidrogenio e carbono (4:1), alem de poder ser processado a baixas temperat