Currently, propanol production highly depends on conventional fossil resources. Therefore, an alternative production process, denoted as "C123", is proposed and evaluated in which underutilized and methane-rich feedstocks such as biogas (scenario BG), marginal gas (scenario MG), and associated gas (scenario AG) are converted into propanol. A first modular-scale process concept was constructed in Aspen Plus, based on experimental data and know-how of the C123 consortium partners. The environmental performance of the considered scenarios was compared at the life cycle level by calculating key performance indicators (KPIs), such as the global warming burden. The results showed that scenario BG is the least dependent on fossil fuels for energy use. Scenario AG seems the most promising one based on almost all selected KPIs when taking into account the avoided gas flaring emissions. The performance of the C123 process concept could be improved by applying heat integration in the process concept.
18 November 2021 in Reaction Chemistry & Engineering
Ethane oxidative dehydrogenation (ODH-C2) is a promising alternative for producing ethylene. Even if SnO2–NiO catalysts are characterized by their long-term stability and high selectivity to ethylene, their kinetic performance has not been investigated in detail yet. In this work, three kinetic models were developed according to redox mechanisms, without assuming a single rate-determining step, for evaluating the ODH-C2 kinetics over an in-house synthesized SnO2–NiO catalyst. Reaction mechanism proposals were based on detailed catalyst characterization (XRD, physisorption of N2, XPS, O2-TPIE, NH3-TPD, H2-TPR, and SEM-EDX) and robust experimental evaluation of the material. Experiments were performed in the kinetic control regime in a micro-reaction unit at temperatures between 360 and 480 °C, inlet oxygen partial pressures between 2 and 15 kPa, inlet ethane partial pressures between 3 and 10 kPa and space times between 9.4 and 45.5 kgcat s mol C2H6−1. In a set of additional experiments, feeding ethylene instead of ethane, the conversion ranged from 1.5 to 14% and CO2 was the only reaction product. Physicochemical and statistical criteria were employed to discriminate between the performance of the considered redox mechanisms. In analyzing the kinetic results, it was found that: outlet molar flow rates were better fitted by the redox mechanism not accounting for the chemisorption of hydrocarbon-based molecules and considering the adsorption of oxygen species on active sites rather than their insertion into the lattice; water was the component with the highest affinity on the active sites; and ethylene and carbon dioxide production is associated with activation energies ranging from 66–94 kJ mol−1 and 80.0–113.0 kJ mol−1, respectively. These findings contribute to the mechanistic understanding of ODH-C2 and provide a reliable model for the future design and scale-up of the process.
27 June 2023 in Industrial & Engineering Chemistry Research