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Guo J.,University of Sichuan | Guo J.,National Engineering Research Center for Flue Gas Desulfurization | Guo J.,Sichuan Prov Environmental Protect Environmental Catalysis And Materials Engineering Technology Center | Shi Z.,University of Sichuan | And 9 more authors.
Journal of Alloys and Compounds | Year: 2015

A series of Ce0.35Zr0.65-xNdxO2-x/2 (x = 0.05, 0.10, 0.15, 0.20 and 0.25) were prepared, and the combinational effects of Nd and noble metals on the catalytic activities of monolithic cordierite honeycomb catalysts were elucidated. The results showed that the BET surface area and pore volume of CZN3F reach a maximum, 97 m2/g and 0.19 ml/g, but all aged samples undergo a sharp decline. The CZN2 has more oxygen vacancy and higher oxygen storage capacity (OSC) before and after ageing, but OSC of the samples with high Nd content decreases. All fresh samples have cubic Ce0.40Zr0.60O2 phase with nano-size, but the aged samples with low Nd content still exhibit cubic Ce0.40Zr0.60O2 phase. When Nd content (CZN4A) is 20 mol% after ageing at 1000 °C, small Ce0.60Nd0.40O1.80 is segregated from CeO2-ZrO2 cubic phase; when the doped Nd increases to 25 mol% (CZN5A), the CeO2-ZrO2 cubic phase completely converts into Nd050Zr0.50O1.75 cubic phase with 12.4 nm, accompanying a sharp decline of OSC; and O2 pretreatment can change the reductive behavior and H2 consumption of samples because of oxygen absorbed. Noble metals can influence the reduction of Ce0.35Zr0.65-xNdxO2-x/2. Ce0.35Zr0.65-xNdxO2-x/2 shows important differences in the TPR and H2 consumption and can change the dispersion and sintering of noble metals, resulting in different catalytic activities. The light-off temperature (T50%) of catalysts containing CZN2F (C2F) can be as low as 160 °C for CO, 211 °C for NO and 259 °C for C3H8, indicating that appropriate Nd doping is helpful for the improving catalytic activity. © 2014 Elsevier B.V. All rights reserved.


Guo J.,University of Sichuan | Guo J.,National Engineering Research Center for Flue Gas Desulfurization | Shi Z.,University of Sichuan | Wu D.,University of Sichuan | And 5 more authors.
Materials Research Bulletin | Year: 2013

Ceria-zirconia-strontia (Ce0.35Zr0.55Sr 0.10O1.9) and ceria-zirconia-baria (Ce 0.35Zr0.55Ba0.10O1.9) were synthesized using an oxidation-co-precipitation method with hydrogen peroxide (H2O2) as oxidant. The physical and chemical properties of the prepared materials were investigated using Brunauer-Emmett-Teller surface area characterization, transmission electron microscopy, X-ray diffraction, Raman spectra, X-ray photoelectron spectroscopy, and oxygen pulse reaction. The prepared materials were used in preparing three-way catalysts with low Pt and Rh content. Moreover, catalytic activities were evaluated at a fixed bed under a simulated gaseous mixture. The results are as follows: (1) the prepared materials have a face-centered cubic structure and are nano-sized; (2) aged Ce0.35Zr0.55Sr0.10O1.9 has higher oxygen storage capacity (494 μmol/g), better thermal stability (30 m 2/g), good low-temperature reducibility, and high hydrogen uptake after TPR-redox cycles; (3) the light-off temperature (T50) of Pt-Rh/CZS/LA can be as low as 199 °C for CO, 228 °C for NO, and 252 °C for C3H8; and (4) Pt-Rh/CZS/LA has a fairly wide working-window. © 2012 Elsevier Ltd.


Fan L.,University of Sichuan | Chen J.,University of Sichuan | Guo J.,University of Sichuan | Guo J.,National Engineering Research Center for Flue Gas Desulfurization | And 3 more authors.
Journal of Analytical and Applied Pyrolysis | Year: 2013

In this study, pyrolusite and its main metal oxide components, MnO 2 and Fe2O3, were chosen to modify walnut shell-derived column activated carbon by blending method respectively. The desulfurization experiments showed that pyrolusite loaded carbons performed the best toward the removal of SO2. With the optimal dosage of additives, the maximum sulfur capacity of activated carbon loaded by pyrolusite, MnO 2 and Fe2O3 were 227.8, 157.8 and 140.6 mg/g, which were 84.0, 27.5 and 13.6% higher than that of blank activated carbon, respectively. Physiochemical properties of all samples were studied by characterizing with BET, XRD, XPS and FTIR. The results indicated that the higher sulfur capacity of pyrolusite activated carbon was mainly attributed to the synergistic effect of metals mixture (manganese and iron) in pyrolusite which was conducive to the development of proper physicochemical characteristic and higher catalytic activity of activated carbon for desulfurization. It can be concluded that using pyrolusite to modify activated carbon by blending method is a low cost way for improving the sulfur capacity of activated carbon. © 2013 Elsevier B.V. All rights reserved.


Huang T.,University of Sichuan | Li Y.,University of Sichuan | Guo J.,University of Sichuan | Guo J.,National Engineering Research Center for Flue Gas Desulfurization | And 3 more authors.
Asian Journal of Chemistry | Year: 2014

Activated carbon was prepared from walnut shell and blended with Co 2O3 powder by one-step activation method. Better development of texture properties on activated carbon was observed by scanning electron microscopy. N2 adsorption-desorption confirmed that the surface area and micro pores volume increased 45 % and 34.2 % after cobalt addition, respectively, compared to blank samples. The results of Fourier-transform infrared spectra indicated that cobalt oxide improved the formation of basic functional groups (C=O) which would considerably affect the adsorption capability. The surface chemical properties of the activation samples were characterized by energy dispersive spectrum, X-ray diffraction and X-ray photoelectron spectra. Results showed that Co and CoO co-existed on activated carbon after activation. The desulfurization capacity of activated carbon-Co5 was 191.7 mg/g and 49.4 % higher than activated carbon.


Guo J.-X.,University of Sichuan | Guo J.-X.,National Engineering Research Center for Flue Gas Desulfurization | Liang J.,University of Sichuan | Liang J.,National Engineering Research Center for Flue Gas Desulfurization | And 7 more authors.
Applied Catalysis A: General | Year: 2012

Activated carbons from coal were treated with different acids and used as carriers. Ni catalysts supported on untreated and treated activated carbons were prepared by the excessive impregnation method and characterized using Brunauer-Emmett-Teller surface area characterization, X-ray diffraction, and X-ray photoelectron spectroscopy. The desulfurization activity of granular catalysts was evaluated at a fixed bed under a simulated gaseous mixture. The results showed the following: (1) the order of desulfurization activity is AC < Ni/AC < Ni/AC-H 2SO 4 < Ni/AC-HNO 3; (2) the specific surface area of the original activated carbons (723 m 2/g) is less than that of the activated carbons treated with nitric (831 m 2/g) and sulfuric acid (803 m 2/g); (3) acid treatment can affect the surface functional groups of activated carbons, and activated carbons treated with nitric acid can significantly increase CO or CO functional groups, which can enhance the desulfurization performance of the catalysts; and (4) Ni and NiO species coexist in the activated carbons before desulfurization, but after desulfurization, Ni and NiO species disappear and Ni 2O 3 is observed, indicating that Ni species could be involved in the desulfurization reaction. © 2012 Elsevier B.V. All rights reserved.


Yang L.,University of Sichuan | Jiang X.,University of Sichuan | Yang Z.-S.,University of Sichuan | Jiang W.-J.,University of Sichuan | Jiang W.-J.,National Engineering Research Center for Flue Gas Desulfurization
Industrial and Engineering Chemistry Research | Year: 2015

In this study, the effect of manganese sulfate (MnSO4) on desulfurization capacity was investigated through carrying out consecutive desulfurization-regeneration cycles of MnO2-blended activated coke (Mn/AC). It was observed that MnSO4 was produced on the surface of Mn/AC during the desulfurization process, and the amount of MnSO4 accumulated on Mn/AC first increased significantly and then became relatively stable. In addition, the desulfurization results of MnSO4- impregnated Mn/AC indicate that Mn2+ from MnSO4 could form new liquid-phase catalysis, which existed with the solid-phase catalysis (blended MnO2) simultaneously in the desulfurization system. However, an excessive amount of MnSO4 over the surface of activated coke can block the access of SO2 to the pore network, hampering the activity of the solid-phase catalyst and, consequently, resulting in a decrease of desulfurization capacity. © 2015 American Chemical Society.


Zhou Q.-Y.,University of Sichuan | Wang P.-C.,University of Sichuan | Jiang X.,University of Sichuan | Jiang W.-J.,University of Sichuan | Jiang W.-J.,National Engineering Research Center for Flue Gas Desulfurization
Recent Innovations in Chemical Engineering | Year: 2015

Currently, the emission amount of nitrogen oxide (NOx) from the cement industry accounts for about 10-12% of total emissions in China, and the cement industry has become the third biggest source of NOx, following thermal power plants and vehicles. Thus, the task for controlling NOx emission from the cement industry is very urgent. Selective non-catalytic reduction (SNCR) denitrification technology has many advantages, such as low investment cost, short construction period, simple facilities and low operating cost, etc. This technology is suitable for the reconstruction of the existing cement production lines and the matching construction of the new cement production lines, and is currently considered to be the best denitrification technique for cement kilns. The basic principle and process of SNCR in cement kilns were analyzed and the key points of SNCR denitrification process in cement kilns were summarized, including the proper reaction temperature window (850~1050°C), mixing of reducing agent and flue gas, NH3/NOx mole ratio, residence time, the control of ammonia escape and the effect of calcium base powder. The current status of SNCR simulation and industrial application in cement kilns were also comprehensively analyzed, together with the future development direction of SNCR denitrification technology in cement industry. © 2015 Bentham Science Publishers.


Wang W.,University of Sichuan | Jiang W.,University of Sichuan | Su S.,National Engineering Research Center for Flue Gas Desulfurization | Zheng T.,University of Sichuan
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2013

In order to determine the optimum operating conditions of flue gas desulfurization processes with pyrolusite slurry, Computational Fluid Dynamics (CFD) was adopted to simulate the multiphase flow in Jet Bubbling Reactor (JBR). The standard k-ε turbulent model and Eulerian multiphase flow model were adopted to simulate the flow field and gas-liquid dispersion in JBR, and gas holdup variance was proposed to quantitatively describe the gas dispersion. The effects of the submergence depth of up impeller and the liquid height on overall gas holdup and gas holdup variance were investigated, and the variance of the ratio of upper gas-bearing height to lower gas-bearing height and the gas holdup variance were analyzed. The results showed that the computed gas-liquid flow field agreed well with the experimental and numerical results in the literatures. The submergence depth of up impeller and the liquid height had significant effects on the overall gas holdup and gas holdup variance in JBR. The overall gas holdup was found to decrease with the increase of the depth of up impeller, and it firstly increased and then decreased with the increase of liquid height. In addition, the gas holdup variance increased with the increase of the submergence depth of up impeller, but decreases with the increase of height ratio. It was concluded that a liquid height of 260~280 mm might be the best, and the submergence depth of up impeller can be determined using a height ratio of 2.


Guo J.,University of Sichuan | Guo J.,National Engineering Research Center for Flue Gas Desulfurization | Shi Z.,University of Sichuan | Wu D.,University of Sichuan | And 5 more authors.
Applied Surface Science | Year: 2013

CeO2-ZrO2-MxOy (M = Y; La) mixed oxides, prepared by co-precipitation method and characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Raman spectra (RM) and oxygen pulse reaction, were comparatively investigated to elucidate the combinational effects of Y and/or La oxide promoters on the catalytic activity and anti-aging performance of monolithic cordierite honeycomb catalysts with low Pt and Rh content. The catalytic activities, water-gas shift (WGS) and steam reforming reaction (SR) were studied under a simulated gas mixture. The catalysts were also characterized by H2-temperature-programmed reduction (H2-TPR) and O2-temperature-programmed desorption (O2-TPD). The results showed that the prepared CeO 2-ZrO2-MxOy oxides have a face-centered cubic fluorite structure and are nanosize. La3+ ions can significantly improve thermal stability and efficiently retard CeO 2-ZrO2 crystal sintering and growth. Doped CeO 2-ZrO2 with Y3+ and La3+ has 105 and 60 m2/g surface area and 460 and 390 μmol/g OSC before and after aging. The T50 of fresh Pt-Rh/CZYL/LA is 170 °C for CO, 222 °C for C3H8 and 189 °C for NO, and shift to 205, 262 and 228 °C after hydrothermal aging, which are better than those of Pt-Rh/CZY/LA or Pt-Rh/CZL/LA. WGS and SR are relate to the OSC of oxygen storage materials and absorbed oxygen species on the catalyst surface and affect the three-way catalytic activities of catalysts. The reductive property of noble metals and the dissociatively adsorbed O2 on the surface of catalysts are closely related to the catalytic activities. © 2013 Elsevier B.V. All rights reserved.


Jiang J.-C.,University of Sichuan | Jiang X.,University of Sichuan | Yang Z.-S.,University of Sichuan | Yang Z.-S.,National Engineering Research Center for Flue Gas Desulfurization
Recent Patents on Chemical Engineering | Year: 2013

SO2 and NOx in flue gas are major air pollutants responsible for acid rain and photochemical smog. The removal of SO2 and NOx by activated coke is a technology with some advantages, such as simultaneous removing SO2, NOx and particulate, high efficiency of purification and no secondary pollution. The used activated cokes can be regenerated by heating or water washing treatment to recover their activity, and the concentrated sulfur desorbed can be recycled as elemental sulfur, sulfuric acid or liquid SO2. This paper describes the principle and process of flue gas desulfurization and denitrification by activated coke. The paper also systematically summarizes the raw materials and production processes of activated coke, regeneration of used activated coke published in patents. Finally, future research directions are suggested. © 2013 Bentham Science Publishers.

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