Micromixing characteristics of a tubular packed bed reactor with different packings were investigated by adopting the competitive parallel reaction, namely, the Villermaux–Dushman reaction. Better micromixing efficiency was achieved with the tube packed with Winpak® compared to that packed with Mini Ring or Mellapak™ or the empty tube. The segregation index (XS) decreased as the volumetric flow rate increased, but increased with increasing volumetric flow ratio. Moreover, the micromixing time (tm) was calculated using an incorporation model based on the experimental data. The minimum tm value of the tube packed with Winpak® (tm=1.54 ms) was less than that of the tube packed with Mini Ring (tm=2.73 ms) or Mellapak™ (tm=2.14 ms) or the empty tube (tm=3.79 ms).
The pore structure and surface chemistry of commercial activated carbon were modified by microwave heating at 600°C, 700°C, and 800°C and chemical treatment with NaOH, Na2CO3, and NaHCO3. The pore structures of the modified adsorbents were characterized by nitrogen adsorption/desorption; whereas, the surface functional groups were determined by Fourier transform infrared spectroscopy and Boehm titration. Furthermore, the effects of the microwave heating and chemical modification on the adsorption of acetone were investigated experimentally. The adsorption process was studied based on the adsorption equilibrium and adsorption energy of the adsorbents. The results indicate that the amount of acidic surface functional groups decreased; whereas, the amount of basic surface functional groups increased after the chemical and microwave heating treatments. Moreover, the microwave heating treatment was more effective than the chemical treatments for optimizing the pore structure of the activated carbon. The micropore volume showed good linear correlation with the adsorption capacity; whereas, the adsorption energy reflected that the adsorption of acetone on the ACs was mostly physical adsorption. The adsorption of acetone on ACs was better described by the Langmuir equation than the Freundlich equation.
Municipal solid waste processing has attracted the attention of the government with economic growth. The application of the refuse-derived fuel (RDF) technology in cement plants can effectively solve the issue of processing municipal solid waste (MSW). This paper focuses on studying the properties of RDF to improve its applicability in cement plants. The thermal behavior of RDF, typical components of RDF (wood, food residue, fabric, and plastic), and their mixtures are investigated by means of thermogravimetric analysis (TGA). In addition to TGA, kinetic analysis was also performed on RDF and its typical components. The combustion of RDF has four major thermal stages: release of moisture, combustion of volatiles, combustion of fixed-carbon, and further combustion of fixed-carbon. The synergistic effect does not exist during the co-combustion process of biomass and biomass components of RDF, but it does during the co-combustion of biomass and combustible non-biomass of RDF, leading to a lower activation energy of RDF at 200–400°C and 400–600°C. The combustion of typical components can be approximately regarded as a first-order reaction.