| Abstrakt: |
This study investigates a novel concept to coproduce high-purity H2and syngas, which couples steam methane reforming with CaO carbonation to capture the generated CO2and dry reforming of methane with CaCO3calcination to directly utilize the captured CO2. The thermodynamic equilibrium of the reactive calcination stage was evaluated using Aspen Plus via a parametric analysis of various operating conditions, including the temperature, pressure, and CH4/CaCO3molar ratio. Introducing a CH4feed in the calcination stage promoted the driving force and completion of CaCO3decomposition at lower temperatures (∼700 °C) compared to applying an inert flow, as a result of in situCO2conversion. A conceptual process design was investigated that employs a system of two moving bed reactors to produce nearly equivalent volumetric flows of pure H2and a syngas stream with a H2/CO molar ratio close to 1. A solar reactor was examined for the reactive calcination step to cover the energy requirements of endothermic CaCO3decomposition and dry reforming. The overall exergy efficiency of the process was found equal to ∼75.9%, a value ∼4.0 and ∼8.0% higher compared to sorption-enhanced reforming with oxy-fuel and solar calciner, respectively, without direct utilization of the captured CO2. |
