Diseño y desarrollo de reactor lecho fijo catalítico para gasificación de biomasa de banano en la producción de hidrógeno

Abstract

Hydrogen and its production are currently an important research topic, since it is considered a clean energy vector that can be used in thermal machines or as a fuel without greenhouse gas emissions, which would contribute to the protection of the environment. There are several methods that are currently being investigated for the hydrogen production, among these the biomass gasification stands out. In general, this latter is carried out in two stages: hydrolysis of the biomass to produce water-soluble compounds and the reaction stage of gasification of these compounds. The use of catalysts in the gasification of biomass favors the formation of hydrogen, as well as reduces the formation of tar, which translates into a higher conversion of the biomass. One of the most abundant biomass in our country is the residue from banana plantations, whose energy potential to produce hydrogen has not yet been evaluated. Due to the aforementioned, the objective of this work was to design a bed catalytic reactor to carry out the banana gasification. For the design of the reactor, the length and diameter were estimated considering fluidization conditions and a ratio height/diameter of 3/1. After the design and construction of the reactor, the catalyzed and uncatalyzed gasification reaction was carried out at conditions of temperature of 640 °C, atmospheric pressure, mass of banana residue of 11.75 g, particle diameter of 1.84 mm biomass, and superheated water vapor as a gasifying agent. The catalyst used in the fixed bed was Ni/Al2O3, which was synthesized by coprecipitation of Ni(NO3)2.6H2O and Al(NO3)3.9H2O. The banana biomass was loaded into the reactor between two # 80 Tyler grids, in order to support and prevent carryover. Similarly, in the catalyzed reaction, the catalyst was placed between 2 grids of #200 Tyler, on the biomass bed. The gaseous mixture resulting from the reaction (superheated steam and synthesis gas) was condensed with excess water, and the synthesis gas was separated by a two-phase separator. Finally, the synthesis gas passed through a silica gel filter and was collected in a 1L Tedlar sleeve for analysis by gas chromatography. The design results established a reactor length of 9 cm and 3 cm in diameter. In the uncatalyzed reaction, the components obtained in the highest percentage were carbon dioxide> hydrogen> ethylene. On the contrary, in the catalyzed reaction, it was obtained: hydrogen> ethylene> carbon dioxide. The hydrogen content went from 25.8 %mol to 51.8 %mol when using a catalyst; while carbon dioxide reduced its molar content by 50%. Additionally, a mass and energy balance established a conversion of 0.295 based on water vapor, and a global heat transfer coefficient of 4.13 W/m2K. The results of this study show the good selectivity of the used catalyst towards the formation of hydrogen and reduction of carbon dioxide