Papers by Author: Chang Qing Dong

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Authors: Teng Ge Mi, Ying Zhao, Chang Qing Dong, Wei Liang Cheng
Abstract: In this paper, a dual fluidized bed has been established. The effect of bed material build-up height and gas velocity on the solid circulation rate of CFB (circulating fluidized bed) and BFB (bubble fluidized bed) has been studied. The results show that the solid circulation rate is increased with the increasing of gas velocity Uc and the bed material build-up height. Bed material build-up height of BFB and CFB is changed with the changing of gas velocity Uc. The bed material heights of CFB and BFB have been also investigated in this experiment.
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Authors: Si Mo Shi, Wu Qin, Chang Qing Dong, Wen Yan Li
Abstract: This paper is focused on the experimental research of Fe-based oxygen carriers using coal ash as support material. Influence of coal ash size, foamer content, temperature on reactivity of Fe-based oxygen carrier for CO oxidation were conducted in thermogravimetry analyzer (TGA). Experimental results show that conversion of the oxygen carrier could attain 100% under 750 °C, and samples that made from mean coal ash grain size of 0.06 mm are more active than that of 0.09 mm, which prove tiny coal ash grain size can enhance reactivity of oxygen carriers. Besides, reactivity of oxygen carriers under 850 °C are lower than 750 °C for that relative high temperature would cause sintering of the Fe-based oxygen carriers.
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Authors: Fa Min Shi, Lei Wang, Si Mo Shi, Han Fei Zhang, Chang Qing Dong, Wu Qin
Abstract: A DFT study of the catalytic properties of CuO/CNT and CuO@CNT complexes for the heterogeneous catalytic ozonation has been performed. We illustrated the atomistic details of CuO/CNT and CuO@CNT with a quantitative and qualitative discussion within such an electronic structure characteristics. Ozone was catalytically decomposed into an atomic oxygen species and oxygen molecule on both the surface inner and outer CuO@CNT complex, while ozone can only decompose over CuO on the outer surface of CuO/CNT, with partial electrons transfer from CuO/CNT and CuO@CNT complexes to the adsorbate. Then the atomic oxygen reacted with the water molecule to form two hydroxyl groups on the surface, promoting the reaction chain for the generation of•OH which, in turn, lead to an increase in the catalytic ozonation efficiency. Results show synergetic confinement effect of metal oxide nanoparticles inside CNT could also lead to an acceleration of ozone decomposition and the generation of •OH on the inner and outer surface of carbon-nanotube containing catalytic particles.
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Authors: Yuan Fang Zhao, Shi Guan Yang, Ji Hong Li, Yong Mei He, Qiang Lu, Chang Qing Dong
Abstract: In order to study characteristics of anaerobic co-digestion of corn straw and cabbage, the experiment was performed with corn straw to cabbage (S:C) of 4:1, 6:1 and 10:1 based on total solids (TS) at 35±1°C at initial TS of 8%. The effects of co-digestion on pH, volatile fatty acid (VFA), and biogas yield were examined. Results showed that the S:C of 4:1 was optimal with accumulative biogas yield of 334.53mL/gTS compared with S:C of 6:1 and 10:1 with accumulative biogas yield of 289.31mL/gTS and 311.37 mL/gTS, respectively. This should be attributed to the high VFA concentration achieved by S:C of 4:1.
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Authors: Han Fei Zhang, Guo Qin Du, Qiao Hong Dong, Cai Xia Lv, Si Mo Shi, Chang Qing Dong
Abstract: Thermogravimetric analyzer has been employed in this paper to test the combustion properties of four kinds of mixed biomass fuel with sludge, domestic waste, swill, coal and grass as major components. Combustion characteristic parameters were obtained through series of experiments, and burning activation energy was got by kinetic analysis. Research results show that ignition temperature of mixed biomass fuel was relatively low and the mixed biomass fuel could be burned easily. The calculated burnout characteristics index and combustion characteristic index showed that combustibility of sample A is the worst while sample D is the best among four materials. Combustion kinetics calculations about the four samples showed that average activation energies for A, B, C and D under the low and the high combustion temperature are 47.02 kJ/mol and 50.51 kJ/mol, 28.10 kJ/mol and 26.98 kJ/mol, 27.93 kJ/mol and 26.72 kJ/mol, and 23.26 kJ/mol and10.73 kJ/mol, respectively, which present the order of activity: D>C>B>A. Results indicated that sample D has the best component proportion which could easily break down and burn out. Furthermore, combustion characteristic index of mixed biomass depends on the proportion of components, where the lower proportion of domestic waste in mixture, the better combustion characteristic index of mixed biomass fuel.
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Authors: Shu Hua Su, Shi Ye Feng, Yuan Fang Zhao, Qiang Lu, Wei Liang Cheng, Chang Qing Dong
Abstract: The selective catalysis reduction (SCR) is one of the most promising technologies for NOx reduction at present. There are three types of NH3-SCR catalysts in the market, honeycomb catalyst, plate-types catalyst and corrugated catalyst. This paper firstly describes the preparation of the three types of catalysts, and then analyzes their performance. The analysis indicates the catalyst structure plays an important role on their performance. The honeycomb catalyst and plate-type catalyst are widely utilized in world’s coal power station, which should be due to their excellent capabilities of ash prevention, wear resistance and anti-poisoning.
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Authors: Cai Juan Zhang, Li Gang Wang, Ling Nan Wu, Tong Liu, Qiang Lu, Chang Qing Dong
Abstract: With the social rapid development, the earth's limited primary energy such as coal, oil, natural gas etc will be exhausted; energy problem has caused worldwide widespread attention. Therefore, under the development of renewable energy, without exception, each country is actively trying to explore the new theory and using energy-saving and technology to improve energy utilization ratio and reduce the energy consumption and the harm on environment. Scientific analysis of energy saving is an important link of digging energy saving potential, effective energy analysis method plays a pivotal role in implementing saving energy. This paper summarized several energy analysis methods on the basis of the first and second law of thermodynamics, introduced the most widely used enthalpy analysis method, entropy analysis, exergy analysis and exergy economic analysis which are based on the second law of thermodynamics, introduced emphatically the specific consumption analysis theory development with exergy analysis and exergy economic analysis.
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Authors: Jing Hui Song, Tao Wang, Jing Gao, Xian Bin Xiao, Chang Qing Dong, Xiao Ying Hu
Abstract: Through MFIX software, a three-dimensional numerical gas-solid flow models without chemical reactions is developed to the distributions of solids phase volume fraction and velocities in a 220t/h rectangular cross-section biomass CFB with a height of 3m. The maximum of erosion occurs at the near-wall side at y=0.95m on the front-wall and back-wall. In transition region(0.8-1.4m) of the left-wall and right-wall, typical core-annular regime can be observed, particle in the core region have the tendency to move to the corner. The maximum of erosion occurs at the corner formed between the walls in the role of downward movement of particle. And the lateral movement of particles are obvious enhanced between the core region and back-wall in the role of exit effect, which lead a certain degree of lateral erosion between the core region and back-wall at the left-wall and right-wall.
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Authors: Jing Hui Song, Tao Wang, Xiao Ying Hu, Chang Qing Dong
Abstract: A two-dimensional numerical gas-solid flow models without chemical reactions is developed to simulate gas-solid flow in the fluidized bed boiler through MFIX software. Platen heating surfaces is considered in the upper of the furnace. Considering that velocity and concentration are the most factor effecting on erosion, there are three main area suffered serious erosion: (1) There is a maximum velocity at the position ( X = 57 cm, Y= 60 cm) on the right side of the wall, which will produce serious impact and erosion. (2) In the vicinity of position (X = 57 cm, Y= 140 cm) will suffer serious impact and tear. (3) As to the platen heating surfaces, the lower part which connect with flow is slightly wear and impacted. While the velocity on the right part is relatively large, especially in the corner of position (X = 24 cm, Y= 147 cm) reach a maximum.
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Authors: Ning Wang, Qin Liang Tan, Da Long Jiang, Ying Zhao, Xiao Ying Hu, Chang Qing Dong
Abstract: A mathematical model is developed for the gas flow in a biomass-fired grate boiler with inner dust removal device, with the purpose to optimize the combustion condition. The distribution of gas flow is determined by the air flow ratio and the optimization is realized by the particular simulation. The optimal air flow is obtained by the analysis of various air flow ratios, via the comparison of flow characteristics and turbulence kinetic energy. The results of the numerical simulation show that the optimum air flow can help the sufficient the mixing and burnout of combustible in the furnace. It clearly indicates that the numerical simulation can be an effective tool for the practical guidance.
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