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Ren G.,North China Electrical Power University | Pei P.,Beijing Shenwu Environment and Energy Technology Corporation | Zhang K.,North China Electrical Power University | Wen D.,University of Leeds
Asia-Pacific Journal of Chemical Engineering | Year: 2014

Tapered fluidized-bed reactors are suggested for biomass catalytic pyrolysis in this work. Both experiments and computational fluid dynamics simulations on hydrodynamics are conducted in a two-dimensional bed with an overall taper angle of 43.8° by using rapeseed as biomass and resin as substitutable catalyst. The results show that the jet penetration depth decreases with increasing initial bed height or decreasing jet gas velocity. However, the jet penetration depth displays a first-increase and then-decrease tendency with increasing resin fraction or annular gas velocity. A comparison of hydrodynamics between measured and simulated data, including the stochastic nature of the jets, identifies that the simple non-viscous two-fluid model can be used to predict the jet behaviors of both mono-particle system and well-mixed biomass mixtures. The results provide fundamental information for the design and scale-up of tapered fluidized-bed reactors for solid biomass catalytic pyrolysis. Copyright © 2013 Curtin University of Technology and John Wiley & Sons, Ltd. Copyright © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.

Wu N.,Beijing University of Chemical Technology | Li B.,Beijing University of Chemical Technology | Ma W.,Beijing University of Chemical Technology | Ma W.,Beijing Shenwu Environment and Energy Technology Corporation | Han C.,Beijing University of Chemical Technology
Microporous and Mesoporous Materials | Year: 2014

The lacunary polyoxometalate (LPOM) encapsulated into the hexagonal mesoporous silica matrix materials were successfully prepared via a directly synthesis method by adjusting pH of the preparation system from 2.0 to 6.0. The materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption-desorption measurements, scanning electron microscopy, X-ray fluorescence analysis, and high-resolution transmission electron microscopy. The results show that the samples possess an ordered pore structure with which changed from uniform ribbing-type to cobweb shape cavity along with the LPOM content increasing from 0% to 30%. The materials possess a high specific surface area of 878-626 m2 g -1 and a mesopore diameter of about 3.8 nm. They also show an excellent catalytic performance and a good reusability for the esterification of n-butanol with acetic acid. © 2013 Elsevier Inc. All rights reserved.

Qu Y.,China University of Mining and Technology | Chu M.,China University of Mining and Technology | Ding L.,Beijing Shenwu Environment and Energy Technology Corporation | Zhang H.,China University of Mining and Technology | Wang F.,China University of Mining and Technology
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2014

The heat fragmentation characteristics of lignite were studied in a fixed-bed and rotary kiln. The results show that the degree of fragmentation in the fixed-bed was increased with the increasing of temperature and feed size. The total fragmentation rate α of 20.43%-36.94% and pulverization rate β of 5.03%-9.24% were achieved for 6-13 mm feed at 400-700°C. When the feed size increased from 6-13 mm to 20-25 mm, α is increased from 25.03% to 80.63% and β is 4.35%-5.60%. The rotary rate is the main parameter for fragmentation in the rotary kiln. The α of 66.67%-78.41% and β of 10.26%-14.78% for 13-20 mm feed were achieved at 105-230°C and 5 r/min rotary rate. The degree of product fragmentation and pulverization are higher. When rotary rate increased from 3 r/min to 9 r/min, α increased from 57.63% to 75.82% and β is 11.05%-11.88%. Through the analysis on pore structure, volatile content and surface appearance of upgraded lignite, the key factors affecting fragmentation are as follows: the change of pore structure, water vapor behavior, volatile arising and heat processing parameters.

Huang H.,Harbin University of Science and Technology | Wu B.,Harbin University of Science and Technology | Wang W.,Beijing Shenwu Environment and Energy Technology Corporation | Gao T.,China Electric Power Research Institute
IET Conference Publications | Year: 2014

This paper proposes a novel coordinate rotation digital computer (CORDIC)-based fast radix-2 algorithm for computation of the discrete sine transforms (DST). The proposed algorithms can generate the next higher order transforms from lower order transforms and have some distinct advantages, such as regular and purely feed forward data path, in place computation, unique post-scaling factor and arithmetic-sequence CORDIC rotation angles. Compared to existing algorithms, these proposed algorithms not only have lower arithmetic complexity, but also admit efficient pipelined VLSI implementation. In addition, an easy way to obtain the fast inverse DST by using the orthogonal property is presented.

Pei P.,China University of Petroleum - Beijing | Pei P.,Queen Mary, University of London | Pei P.,Beijing Shenwu Environment and Energy Technology Corporation | Zhang K.,China University of Petroleum - Beijing | And 2 more authors.
Powder Technology | Year: 2012

In the Eulerian-Eulerian approach for simulating gas-solid two-phase flow, a proper selection of an interfacial force to describe the momentum transfer between the two phases has a significant influence on the particle dynamics. Based on a detailed review of the inter-phase drag force models, a simple two-fluid model with zero particle-phase viscosity is used to investigate the effects of inter-phase drag force on the jet characteristics in a two-dimensional jetting fluidized bed. The simulation results from different inter-phase drag force models are compared with a designed experimental study. Both qualitative and quantitative results show that the jet behavior, including the distribution of solid volume fraction, bed pressure drop, jet penetration depth and jet frequency, could be significantly affected by the selection of drag force models. None of the models assessed in this work could predict all these parameters accurately. Some models can predict the averaged value well but are weak in predicting the dynamics and vice versa, which calls for a caution in interpreting data based on a single drag model. © 2011 Elsevier B.V.

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