Search

Browse

• Communities
• Authors
• Year
• Titles
• Subjects

My Space

• Login

Characterization and catalytic performance evaluation of Ru/MCM-41 catalysts with different metal loading under the Sabatier reaction (CO2 hydrogenation towards methane)

Emmanouil Orestis

Full record

---

Summary

Climate change is one of the most crucial environmental issues today. Many efforts are being carried out globally to limit its impact and help forward a transition to a production process with positive environmental footprint.Various new technologies are helping in this effort, attempting to reduce greenhouse gas emissions, such as CO2, or even utilize them in various ways. One such technology is the reaction of carbon dioxide hydrogenation to produce methane, methanol as well as other hydrocarbons for later use in other industrial applications with lower environmental impact.In present thesis, a comparative study of ruthenium catalysts supported on MCM-41 was conducted for the catalytic reaction of CO2 methanation. The purpose was to study their behavior regarding their kinetic state, stability, and physiochemical characteristics. The catalysts were studied in terms of their conversion of CO2, CH4 productivity, CO productivity, CH4 selectivity and CO selectivity. The catalysts used, all with different metal loading, were 1.5% Ru/MCM-41, 3% Ru/MCM-41 and 10.11% Ru/MCM-41. First, porosimetry experiments were performed to determine the structural characteristics of the catalysts under study, i.e., the total surface area, the total pore volume, and the average pore size diameter of the catalysts. Afterwards, the kinetic study of the catalysts was carried out to study their performance in a temperature range of 100-600°C and at three different values of reactor space velocity (Weight-basis Gas Hourly Space Velocity, WGHSV) equal to 21,600 mL/gh, 60,000 mL/gh and 120,000 mL/gh. The experiments were carried out in a fixed bed reactor, in a constant feed composition, 5% CO2, 20% H2 and 75% Ar, i.e., at a H2/CO2 = 4 ratio corresponding to the stoichiometry of the Sabatier reaction (CO2 methanation).Catalytic stability experiments followed, to evaluate the catalysts in terms of their performance in relation to time. The experiments lasted 12 hours. The temperature was kept constant at 380°C as well as the WGHSV value which was equal to 60,000 mL/gh. The results of the above experiments showed that all three catalysts present a very good performance in the CO2 methanation reaction and are extremely stable over time. The catalyst with the highest ruthenium loading, 10.11% Ru/MCM-41, appeared to have the best performance. Significant differentiation in the results was also demonstrated by the change in the WGHSV, with the lower value leading to better results.

Available Files

Services