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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.

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.

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.

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.

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.

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