Producing carbon nanotubes from thermochemical conversion of waste plastics using Ni/ceramic based catalyst

As the amount of waste plastic increases, thermo-chemical conversion of plastics provides an economic flexible and environmental friendly method to manage recycled plastics, and generate valuable materials, such as carbon nanotubes (CNTs). The choice of catalysts and reaction parameters are critical to improving the quantity and quality of CNTs production. In this study, a ceramic membrane catalyst (Ni/Al2O3) was studied to control the CNTs growth, with reaction parameters, including catalytic temperature and Ni content investigated. A fixed two-stage reactor was used for thermal pyrolysis of plastic waste, with the resulting CNTs characterized by various techniques including scanning electronic microscopy (SEM), transmitted electronic microscopy (TEM), temperature programmed oxidation (TPO), and X-ray diffraction (XRD). It is observed that different loadings of Ni resulted in the formation of metal particles with various sizes, which in turn governs CNTs production with varying degrees of quantity and quality, with an optimal catalytic temperature at 700 °C

Development of Ca/KIT-6 adsorbents for high temperature CO2 capture

The incorporation of CaO into an inert porous solid support has been identified as an effective approach to improve the stability of adsorbents for CO2 capture. In this work, we focus on enhancing the capacity of carbon capture and cyclic stability of CaO by impregnating CaO particles into a three-dimensional mesoporous silica (KIT-6) support. At a low CaO loading, the three-dimensional mesoporous support was filled with CaO nano-particles. The further increase of CaO loading resulted in the aggregation of CaO particles on the external surface of the support material, as identified by electron microscopy analysis. These CaO/KIT-6 adsorbents show excellent high-temperature CO2 carbonation/calcination stability over multiple cycles of CaO carbonation and calcination. The enhancement of the performance of carbon capture is attributed to the interaction between CaO and the silica skeleton of KIT-6 through the formation of interfacial CaSiO3 and Ca2SiO4 which enhanced the resistance of CaO sintering

Study on the formation of direct reduced iron by using biomass as reductants of carbon containing pellets in RHF process

To investigate the possibility of using biomass reductants instead of fossil fuels in the formation of direct reduced iron (DRI) in rotary hearth furnace (RHF), three kinds of cheap biomass such as bamboo char, straw fiber and charcoal were selected as reductants to compare with anthracite and graphite. The effect of reductants, temperature, dwelling time, C/O ratio and particle sizes on the shrinkage, strength and metallization of the biomass/ore pellets was investigated and discussed. The optimized reduction conditions were obtained as 1200 degrees C, 20min, C/O = 0.7 and the particle size range of &lt;0.15 mm, 1-2 mm and 015-0.3 mm for straw fiber, bamboo char and charcoal respectively. The results showed that straw fiber was considered as an optimal reductant in the formation of direct reduced iron instead of fossil fuels. By the techniques of scanning electron microscope (SEM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD), the mechanism of biomass as reductants was revealed. Volatile matter was confirmed to play an important role in the formation of DRI when biomass used as reductants. (C) 2017 Elsevier Ltd. All rights reserved.</p