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A Novel Hydrogen And Oxygen Generation System, Zhiyong Peng

LSU Master's Theses

This study examined the three phases of the sorption-enhanced SMR process for H2 production: production of low-CO hydrogen using the standard Ni-based reforming catalyst and high purity CaO sorbent precursor, evaluation of combined reforming catalyst-sorbent samples supplied by TDA, and an Aspen simulation study of the process for simultaneous production of H2 and O2. The production of low-CO (<20ppmv) hydrogen was studied using the single-step sorption-enhanced steam methane reforming process. The effects of temperature, volumetric feed rate, and feed gas composition on the purity of H2 and the content of CO were investigated. The feasibility of producing 95+% H2 with CO content of less than 20ppmv was experimentally proven in a test at 480¡ãC and 5 atm using a commercial Ni-based catalyst and the calcium-based CO2 sorbent. The feed gas contained 20% CH4 and 80% H2O, while the product gas contained 97.8% H2 and 17 ppmv CO. With this low CO concentration, the product can be used in a proton exchange membrane (PEM) fuel cell without further purification. The catalyst-sorbent samples from TDA Research Inc. were extensively studied and evaluated with respect to their performance in the steam-reforming reaction using both the fixed-bed reactor system and TGA. The activity of the catalyst samples having different compositions was examined and compared at different temperatures and space velocities using a feed gas containing 11.1% CH4 with a steam-to-carbon (S/C) ratio of 3.0. The sorption activity and durability was also examined in the TGA system. The overall hydrogen and oxygen co-production process was studied and evaluated using the Aspen Plus simulator. Material and energy balance calculations showed that this system can produce 99+% purity hydrogen and oxygen simultaneously with efficient energy integration. This process is balanced on power consumption and generation, so no external power is required.