Taiyuan, China
Taiyuan, China

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Li J.-J.,Tsinghua University | Zhang M.,Tsinghua University | Yang H.-R.,Tsinghua University | Lu J.-F.,Tsinghua University | And 2 more authors.
Fuel Processing Technology | Year: 2016

The NOx emission of circulating fluidized bed (CFB) boilers in China is more and more stringently controlled due to the updated national emission regulation (NER). Based upon the theory of CFB combustion and previous research results related to NOx formation mechanism, a technical route was proposed by means of re-specifying the fluidization state in CFB boilers, to achieve the ultra-low NOx emission without installing the deNOx equipment additionally. The main method is to increase the solid circulating rate and decrease the bed inventory as well as the mean size of bed material, which would influence the bed temperature and oxidizing/reducing atmosphere distribution, and thereby benefit for the reduction of NOx emission. Besides, the reasonable control of bed temperature and air supply should be considered. This technique has been demonstrated to be effective in three CFB units with different capacities (150t·h-1, 260t·h-1 and 560t·h-1) and burning different types of coal. No obvious decrease of combustion efficiency was found in the field tests. The technical route provides a feasible approach to further control the NOx emission for CFB boilers. © 2016 Elsevier B.V.


Li J.,Tsinghua University | Yang H.,Tsinghua University | Lu J.,Tsinghua University | Zhang J.,Taiyuan Boiler Group Company Ltd | And 3 more authors.
Ranshao Kexue Yu Jishu/Journal of Combustion Science and Technology | Year: 2013

Due to the new NOx national emission regulation, it is more and more significant to reduce the NOx emission. By reconstructing the fluidization state of gas-solid flow in the CFB furnace, the low energy consumption (LEC) CFB boiler was developed and popularized so that the problems of high auxiliary power, serious wear of water-wall and low combustion efficiency could be solved. However, it is still uncertain to evaluate the influence of the technology on NOx emission. Therefore, the NOx generation theory and the main principle of LEC CFB are firstly introduced based on the existing theory and the experimental results. Viewing from the factors of bed temperature and oxidizing-reducing atmosphere, it is demonstrated that the LEC CFB technology has a potential advantage on NOx emission.


Ren X.H.,Taiyuan Boiler Group Co. | Hu K.T.,Tsinghua University | Zhang J.C.,Taiyuan Boiler Group Co. | Liu A.C.,Taiyuan Boiler Group Co. | Yang H.R.,Tsinghua University
Applied Mechanics and Materials | Year: 2014

Taiyuan Boiler Group Co. Ltd. designed and developed an 850t/h CFB boiler with energy saving technology on the principle of "State Specification Design Theory". By measuring the ash formation and attrition characteristic of the design coal, with the one dimension mass balance model developed by Tsinghua University, the bed quality of the bed inventory and the pressure drop were modified. Based on the particle density calculated, the heating transfer coefficients were chosen and the arrangements of the heating surfaces were modified. According to the special operation conditions of the user, the practical working conditions for the boiler are determined so as to assure the technical characteristics and structural properties in 850t/h CFB boiler. © (2014) Trans Tech Publications, Switzerland.


Deng K.,Taiyuan University of Technology | Wang C.,Taiyuan Boiler Group Co. | Wang X.,Harbin Institute of Technology
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2014

The four kinds of 5 μm SiCP/Mg alloy (AZ91) magnesium matrix composite with the volume fraction of 2%, 5%, 10% and 15%, respectively, were fabricated by stir casting. After the solution treatment, forging and hot extrusion, the effect of SiCP on the microstructure and mechanical properties of AZ91 matrix were investigated by compared with the monolithic AZ91 alloy. The results show that the grain size of SiCP/AZ91 depends on the volume fraction of SiCP. The average grain size of composite matrix decreases as the volume fraction increased from 0% to 10%, the grain size increases as SiCP volume fraction continuing increased to 15%. The addition of SiCP can improve the yield strength and modulus of AZ91 significantly, and they increase with the volume fraction of SiCP. The strengthening effects of SiCP on AZ91 matrix are mainly attributed to dislocation strengthening mechanism, grain refinement and load transfer effect, the grain refinement plays a main role on improving the yield strength.


Zhang X.,Taiyuan University of Technology | Zhang J.,CNNC Xinneng Nuclear Engineering Co. | Wu S.,Taiyuan Boiler Group Co. | Liu J.,Taiyuan University of Technology | Zhang X.,Taiyuan Boiler Group Co.
Heat Transfer Research | Year: 2015

Numerical simulations were conducted to examine the heat transfer processes occurring in a steam-water mixing heater that has diff erent inlet steam pressures. The FLUENT, which is a commercial computational fluid dynamics soft ware, and the volume of fluid multiphase flow model were used to simulate the two-phase flow in a steam-water mixing heater. The condensation heat transfer source term and the mass transfer source term, which were obtained by calculating the phase interface temperature gradient, were integrated in the simulation. The simulation results coincide with experimental data and show that the exit speed, temperature, and the nondimensional length of the steam plume increase with increasing inlet steam pressure. © 2014 by Begell House, Inc.


Li J.-M.,Taiyuan Boiler Group Co. | Deng K.-K.,Taiyuan University of Technology
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2012

10 vol% SiCp reinforced magnesium matrix composite was fabricated by stir casting. The composite was treated by solution, hot deformation and aging, respectively. Effect of heat treatment on microstructure and mechanical properties of the magnesium matrix composite was researched. The results show that the massive Mg 17Al 12 phase at grain boundaries disappears, and strength and elongation of the as-cast composite increase obviously after solution treatment. After hot deformation, the grains are refined and the particles distribute much more uniformly, thus the mechanical properties of the composite are improved. By the subsequent aging treatment, the precipitated fine Mg 17Al 12 phase in the magnesium matrix composite is propitious to the enhancement of mechanical properties.


Wang X.,Taiyuan Boiler Group Co. | Wang X.,Taiyuan University of Technology | Wang W.,Taiyuan University of Technology | Hao R.,Taiyuan Boiler Group Co.
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2010

BHW35 steel was welded by automatic submerged-arc welding (SAW) with H08Mn2MoA welding wires and flux HJ350. After stress relief annealing by the postweld heat-treatment system, impact tests on welded joint and base metal were carried out at 20, 100, 200 and 350 °C, and the scanning electron microscopy (SEM) fractograph, metallograph, hardness and chemical compositions of welding seam were analyzed. The results indicate that the highest hardness of HAZ is 291.6 HV. The toughness increases greatly compared with that at room temperature. The temperature peak value of impact absorbing energy of welding seam occurs at weld of 100 °C and both HAZ and base metal of 200 °C. The impact toughness in HAZ is better than that in welding seam. The impact absorbing energy of welded joint is over 47.33 J at room temperature and 134.67 J at 350 °C, which meets the toughness demand for the welded joint and base metal. SEM fractograph indicates that all impact fractures of base metal exhibit ductile dimple, and the impact fractures in welded joint at room temperature exhibit quasi-cleavage and ductile dimple. With the temperature increasing, the fractures subjected high temperature impact all exhibit ductile dimple; the better toughness is, the more obvious tearing feature of ductile dimple is, and the larger the ductile dimple is, the more obvious non-uniform distribution is.


Wang X.,Taiyuan University of Technology | Wang X.,Taiyuan Boiler Group Co. | Wang W.,Taiyuan University of Technology | Li J.,Taiyuan Boiler Group Co. | Wang B.,HIGH-TECH
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2010

Automatic submerged-arc welding and shielded metal arc welding were employed by H10Mn2NiMoA welding wires, E7015-D2 electrode followed by the postweld heat-treatment systems of normalizing, drawing temper and stress relief annealing. Impact tests on welded joint and base metal at 20°C, 100°C, 200°C and 350°C were carried out. Furthermore, SEM fractograph, metallograph and chemical compositions of welding seam were analyzed. The results indicate that the highest hardness of HAZ was: 270.5 HV in SAW; 235.2 HV in SMAW, the toughness increases greatly compared with conditions at room temperature. Peak value of impact toughness of SAW is at 100°C, SMAW is at 200°C, which is close to that of base metal. The impact toughness in HAZ is better than that in welding seam, and it is better in SMAW than that in SAW. The impact toughness of welded joint is upward 96.33 J at room temperature, it is upward 120 J in welded joint at 350°C, and 186 J in base metal, which indicate that the toughness of welded joint and base metal ars in their best at room and high-temperature. SEM fractograph indicates that all impact fractures exhibit ductile dimple, the better toughness, the more obvious tearing feature of ductile dimple. The larger the ductile dimple is, the more obvious non-uniform distribution is.


Zhong W.,Zhejiang University | Xie J.,Zhejiang University | Wang Z.,Taiyuan Boiler Group Co. | Tong S.,Zhejiang University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2011

The flow characteristics of the manifold tended to more complicated since the design structure of header system becoming diversification. To ensure the header system being in safe operation, the manifold need to be having good flow characteristics. The effect from the uneven distribution of heat load to the uneven flow distribution of the manifold and derived the relationship between the heat load and the uneven distribution flow was studied. Meantime, an example was given for verification and analysis. The results show that the distribution flow of the manifold in header system is quadratic with the average density in the single-phase state and in the two-phase state when the friction loss correction factor is constant. The result also shows that the distribution flow of the parallel tubes increases with the increasing of the heat load in the liquid state and in the two-phase state, but decreases with the increasing of the heat load in the steam state. ©2011 Chin. Soc. for Elec. Eng.


Wang X.-Y.,Taiyuan Boiler Group Co. | Lei W.-J.,Taiyuan Boiler Group Co.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2011

The microstructure, hardness, mechanical properties including bend and tensile strength of welded joints for 12CrlMoVG/12Cr2MoWVTiB dissimilar steel as welded and under different temperature of postweld heat treatment were investigated. The results indicate that as temperature of postweld heat treatment increases, microstructure of welded joint turns from temper martensite and a small amount granular bainite to granular bainite and sorbite mixture of gradually, the hardness difference of two-sided weld become diminution. The structural homogenity is improved and the grain size grows up. And tensile-strength and hardness of joint show a trend of decreasing. Because of the substantial relaxation of welding residual stress and the dispersion strengthening of precipitated phase, the decreasing trend becomes less obvious at 740 t. It is found that all 730-770 °C for 1 h heat treating regimes can coniform to operating performance characteristics. In order to prevent the adverse influence on plasticity and toughness, 740-760 ° for 1 h heat treating regimes is preferred.

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