Papers by Keyword: Catalytic Combustion

Abstract: This work applies a 3D multi-scale bottom-up approach for modeling the processes of diffusion and reaction-diffusion in porous catalyst layers. The performance of the random pore model to predict effective transport coefficients are compared with the results of the multi-scale diffusion model. The results of the 3D multi-scale diffusion model are employed in a 1D pseudo-homogeneous reaction-diffusion model with a relative good agreement with the 3D multi-scale reaction-diffusion model. Furthermore, the former multi-scale model was coupled to a full-scale reactor model with good results and high advantages in terms of computational time savings.

Abstract: By doing inside the catalytic combustion furnace with Pd-based honeycomb monoliths of lean natural gas-air mixtures and measuring temperature field and the composition of flue gas, the exhaust gas of Low-carbon catalytic combustion furnace of natural gas can be analyzed and discussed. In addition, the catalytic combustion furnace in the pottery was also investigated, which can reduce the pollutant emission of the product process, and reduce global warming.

Abstract: This paper presents the fabrication and characterization of platinum-based catalytic microcombustor. The platinum catalyst was deposited onto type-304 stainless steel using the wet impregnation method. The stainless steel undergoes controlled conversion coating treatment in sulfuric acid solution to increase the porosity of its surface before the deposition of the platinum catalyst. The scanning electron microscopy result showed that the porosity on the stainless steel surface will depend on the length of treatment time in the sulfuric acid solution. The surface porosity increased as the treatment time increases. The stainless steel surface morphology changed from smooth to ‘cracked-mud’ morphology after treatment in sulfuric acid solution. The treatment time also provide significant effect to the amount of platinum deposited on the stainless steel surface. The energy dispersive x-ray analysis showed that the amount of deposited platinum for 10 seconds of treatment time was 0.68 wt%, whereas those for 20 and 30 seconds were 0.87 wt% and 1.10 wt%, respectively. Liquefied petroleum gas-air combustion result showed that the flame completely submerged inside the microcombustor with a catalyst, whereas portions of flame can be observed at the exhaust for the microcombustor without a catalyst. The minimum air-to-fuel ratios before the combustion blow-out for 10, 20, and 30 seconds of treatment time was 0.5, 0.4, and 0.3 respectively.

Abstract: The wet impregnation method for catalytic microcombustor was characterized by using platinum as a catalyst. The main purpose of this study is to increase the surface porosity of the catalyst support. A high surface porosity indicates that a high amount of catalyst was deposited within the surface areas. The performance of the catalytic microcombustor improves with increasing catalytic surface area. The stainless steel catalyst support was treated with sulfuric acid solution containing polyvinyl (3.89 wt%) and propargyl alcohol (1.48 wt%). Combustion test was performed using LPG-air to test the performance of the catalyst. The surface support treated with polyvinyl (PVA) showed a higher surface porosity and combustion blow-out limit compared with propargyl alcohol. The combustion mode changes from surface to submerged combustion after the catalyst was deposited in the support surface.

Abstract: A novel hexaaluminate material Ca_0.6La_0.4Fe_xMn_1-xAl₁₁O₁₉ was prepared by a micro-emulsion method, and then washcoated on the cordierite substrates to produce monolithic catalysts. The obtained hexaaluminates were characterized by X-ray diffraction and scanning electron microscope. Results show that the particles of the prepared hexaaluminates samples are well-proportioned and small, and that the lower-quantity replacement of Mn²⁺ with Fe³⁺ is of benefit to forming single hexaaluminates crystal phases. After the partial replacement of Mn²⁺ with Fe³⁺ in hexaaluminate, the catalytic activity in methane combustion improved.

Abstract: Catalytic combustion of VOCs was investigated over Mn–Zn mixed oxides supported on cordierite ceramic (Cord) and over the promoted Mn-Zn oxides with γ–Al₂O₃ coating. The properties and performance were characterized by using the XRD, SEM, BET, and TPD techniques. Mn-Zn oxides catalysts with different kinds of γ–Al₂O₃ sol coating were found to possess a high activity, and the Mn–Zn/γ–Al₂O₃/Cord (Mn/Zn=2) was identified as the most active that the temperature of complete combustion of toluene was 250°C. Effects of variation of preparation conditions, including molar ratio of Mn and Zn, loading, calcination temperature and different kinds of γ–Al₂O₃ dipping were investigated.

Abstract: This paper studied the methane/moist air combustion characteristics in smooth microtube and microtubes with five different shape grooves and proposed the microtube groove dimensionless shape factor F=4πS/L2. The results show that the appearance of five grooves make combustion components and velocity occur jumping change and the vortex flow appears. The highest methane conversion rate is for the microtube with triangle grooves, which also indicates that the smaller shape factor is more in favor of methane conversion.

Abstract: In the paper, based on the results of lean gas furnace temperature field, the study was carried out on heating earthenware. Compared with earthenware which heated with electric furnace, earthenware heated with Low-carbon Catalytic Combustion Furnace was having apparent advantages. The content of the pollutants in exhaust gas was detected during heating in the same time. It would be the conclusion that a trace of pollutants was produced in the highly clean combustion furnace production process, from analyzing and comparing the data under the condition of heating with earthenware and heating without earthenware in the catalytic combustion furnace.

Abstract: Nanometer-sized gold particles supported on Cerium Oxide (CeO₂) were prepared by the method of deposition-precipitation. These catalysts exhibited good activity for the combustion of formaldehyde and the factors affected the activity of the catalyst were observed. The results showed that CeO₂ powder prepared by Ce (NO₃)₃.6H₂O and citric acid were small and gold can disperse on CeO₂ easily. 1.83wt% Au/CeO₂ exhibited the highest activity when velocity of 0.37% formaldehyde was 0.5L/min and corresponding contact time between gas and catalyst was 2h. Formaldehyde removal ratio after treating was up to 80% at 80°C and complete burn-off of formaldehyde was achieved at 120°C. The XRD and TEM results indicated that nanogold particles (≤20nm) were dispersed on cerium oxide homogeneously.

Abstract: This article discussed the factors that affect the lifetime of catalyst. For the lifetime of catalyst about catalytic combustion burner III 1100 hours were obtained. The local surface temperatures of monolith, the gas temperature inside channels and pollutant concentrations were measured. The ageing of catalyst to the change of local surface temperatures and gas temperature was approached and its affecting factors were analysed. This will improve the working conditions of catalytic combustion burner in future, and prolong its lifetime of catalyst.