Kinetics of CO₂ Hydrogenation to Hydrocarbons over Iron–Silica Catalysts

Abstract

The conversion of CO2 to hydrocarbons is increasingly seen as a potential alternative source of fuel and chemicals, while at the same time contributing to addressing global warming effects. An understanding of kinetics and mass transfer limitations is vital to both optimise catalyst performance and to scale up the whole process. In this work we report on a systematic investigation of the influence of the different process parameters, including pore size, catalyst support particle diameter, reaction temperature, pressure and reactant flow rate on conversion and selectivity of iron nanoparticle ‐silica catalysts. The results provided on activation energy and mass transfer limitations represent the basis to fully design a reactor system for the effective catalytic conversion of CO2 to hydrocarbons.

Greenhouse gas CO2 hydrogenation to fuels: A thermodynamic analysis

“…Here, it is important to note that there is no significant effect of pressure on the conversion of CO 2 below 270°C. This fact indicates that CO 2 ‐FT reaction will yield desirable results with bit lower chain HCs at low pressure and low temperature, which is supported by various experimental studies conducted at atmospheric pressure . However, increase in temperature up to 477°C is favorable for long chain HCs synthesis at higher pressure .…”

“…Owen et al . have reported the formation of HCs from CO 2 on Cobalt catalsyts at atmospheric pressure with a significant conversion. In the view of above studies, CO 2 hydrogenation provides new opportunities for the development of catalytic processes and sustainable energy.…”

“…Wei et al [12] have reported 22% CO 2 conversion to gasoline range HC with 4% CH 4 selectivity on the fixed bed of Na-Fe 3 O 4 /HZSM-5 catalyst. Owen et al [13][14][15][16] have reported the formation of HCs from CO 2 on Cobalt catalsyts at atmospheric pressure with a significant conversion. In the view of above studies, CO 2 hydrogenation provides new opportunities for the development of catalytic processes and sustainable energy.…”

Shedding Light Onto the Nature of Iron Decorated Graphene and Graphite Oxide Nanohybrids for CO2 Conversion at Atmospheric Pressure

“…The resulting pre‐catalysts were followed by in situ generation of the iron active species through mild hydrogenations and then their testing as nano‐catalyst for the CO 2 activation following existing protocols. In our hands, a surprisingly short exposure time of only 40 minutes was found to give a comparable conversion rate with silica supported catalysts, and this intriguing result was assigned to the layered morphology and the accessible encapsulated iron nanoparticles within the graphene supports, vide infra …”

Highly Selective, Iron‐Driven CO2 Methanation

“…Iron species are known to catalyse both of these reactions, [8b] and it has been shown that combining the RWGS reaction with the irreversible FT process shifts the equilibrium of the RWGS reaction towards products, making both reactions favourable under similar conditions and improving the efficiency of the overall CO 2 hydrogenation process relative to performing the two reactions separately. [9] While methane is a common product of combined RWGS/FT processes, the additional hydrocarbon species produced (e. g. olefins and higher hydrocarbons) have been the primary targets for research thus far, and have left RWGS/FT chemistry under explored as a route to selective methanation. A notable difference between combined RWGS/FT and Sabatier chemistry is that the ideal value of P H2 /P CO2 for combined RWGS/FT processes has been consistently cited in literature as 3 rather than the standard value of 4 for direct CO 2 methanation.…”