Estudo comparativo dos métodos de produção de hidrogênio e carbono sólido usando a reação de decomposição do metano

Abstract

Currently, one of the main routes for obtaining hydrogen is the steam reforming of methane, it is known that the global demand for hydrogen has intensified in recent years, being a potential candidate for the clean and sustainable energy future, however, It is necessary to pay attention to the emissions of polluting gases into the atmosphere, in this aspect, the steam reforming of methane is unfavorable, emitting gaseous pollutants in significant quantities. The thermal decomposition of methane (TDM) is a process that occurs at high temperatures, with or without the presence of a catalyst, forming only hydrogen and solid carbon. Recently, TDM has been studied by several authors as an alternative for producing hydrogen free from emissions of polluting gases such as CO2. In addition to H2, the carbon generated has commercial applications, being a value-added product of the reaction. By varying the process conditions, different types of carbon can be obtained, with different purities and conformations. Among the most valuable are carbon nano fibers. In this work, a bibliographical survey of existing methods for carrying out the thermal decomposition of methane was carried out. A thermal and homogeneous process was simulated in Aspen Plus, considering a daily production of 2.5 tons of hydrogen and 8.4 tons of solid carbon, the main process equipment is a reactor, a cyclone, a PSA-type separation column and a filter. A sensitivity analysis was carried out by varying the pressure and temperature of the reactor, the results showed that by increasing the temperature and decreasing the pressure, methane conversion increases. After the simulation, an economic analysis was carried out, the CAPEX for the simulated process is US$ 3,163,801.00 and the OPEX is US$ 6,934,660.00 per year, while the sale of the products generated is US$ 19,564 ,000.00 per year. After analysis, the process proved to be viable from an economic point of view.