Overview of Catalytic Methanation in Hot Mixing Asphalt Plants Towards Greenhouse Gas Emissions

Road works mainly involve the use of asphalt for pavement construction. Among Hot-Mix asphalt (HMA) production processes, HMA plants are the most commonly used for asphalt production in world. HMA is shown as an industrial activity in which energy consumption can reach 60% of the total energy consumed by the construction and the maintenance of a road during 30 years of service life. Rate of production, bitumen temperature, burner flow rate and type of fuel consumption are the parameters which directly link to energy consumption and greenhouse gas (GHG) emission during HMA plant operation. Carbon dioxide (CO₂) in GHG has increased the temperature of the earth. Introduction of catalytic methanation as a new method in the HMA production was introduced as an effective way to convert CO₂ released from HMA plants to methane (CH₄). The optimum parameters were found through the experimental result which showed that Ru/Cr/Mn (5:10:85)/Al₂O₃ calcined at 700°C with 10 g of catalyst dosage gave 100% of CO₂ conversion, determined using FTIR, and yielded about 80% of CH₄ at reaction temperature of 300°C. Field Emission Scanning Electron Microscope (FESEM) show the presence of dispersed particles with undefined shape covering the catalyst surface. EDX analysis revealed that the mass ratio of Mn was high compared to the other elements. Thus, this study has proven that the catalytic methanation technology as the new effective method in HMA production plants can convert CO₂ in GHG emission to methane (CH₄). In conclusion, it is highly advisable to adapt these alternatives as the green roads and highways industry. (paper)