Abstract
Steam reforming of ethanol (SRE) represents a prominent method for obtaining hydrogen, as it uses a renewable and non-toxic biofuel as a primary feedstock. In order to improve the industrial attractiveness of this catalytic pathway, this work aims to optimize reactor temperatures (°C), pressure (bar), steam-to-ethanol ratio, and feed flow rate (kg/h) to maximize yield and conversion while reducing the energy consumption and the use of raw materials. The plant was simulated using Aspen Plus? software, considering a base case with three fixed-bed reactors in series, a simplified purification process, and compression up to 300 bar. Thermal integration minimized process energy requirements by implementing heat recovery from inter-reactor streams for feed preheating. Upon consolidation of the base case, a screening of key process parameters was conducted via a full 2k factorial experimental design. As a result of this initial statistical analysis (p-value < 0.05), it was observed that the temperatures of the WGS reactors were not statistically significant. As this range was limited by the chosen reaction kinetics, these parameters were kept fixed at the minimum value of 250 °C for the second stage of the optimization study. A Central Composite Design (CCD) was implemented to derive surrogate models for ethanol conversion and hydrogen yield, while Response Surface Methodology (RSM) was employed to delineate optimal operating regions. The analysis revealed that maximizing both the temperature (500-600 °C) and the feed molar ratio (1:8-1:9) to their upper bounds yielded the highest performance metrics.
