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Tong Y.,Zhejiang University | Zhong W.,Zhejiang University | Wu Y.,Zhejiang University | Li Z.,Yantai Longyuan Electrical Power Technology Co. | Tong S.,Zhejiang University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2014

Supercritical and ultra-supercritical boilers are the main development directions of the world's clean coal power generation technology. Performance analysis and calculation are the basis of the design and optimal operation of utility boilers. This paper used the "node" and "branch" concept of the fluid network theory to describe the boiler thermal system. Heat transfer parts were abstract to nodes and the connections between these parts were abstract to branches. The incidence matrix in graph theory was adopted to describe and express the connection relation of the boiler thermal system. The nodes follow the laws of mass conservation, momentum conservation, energy conservation, as well as the equations of heat transfer and heat balance. According to these laws and equations, a general mathematical model to calculate the steady state performance of the boiler thermal system was built. The performance analysis platform of supercritical boilers was based on browser and server which belong to the thin client. The software architecture and implementation of this platform were introduced. Thermal performance of a supercritical boiler reformed was calculated and analyzed. The results verify the validity of the model and method. © 2014 Chin. Soc. for Elec. Eng.


Sun L.,Northeast Dianli University | Ren H.,Northeast Dianli University | Lang K.,Northeast Dianli University | Tang H.,Yantai Longyuan Electrical Power Technology Co. | Hou B.,Yantai Longyuan Electrical Power Technology Co.
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2016

Combining the thermodynamic calculation in sections for large capacity boilers with simplified dynamic model of full-furnace pressure and temperature, and based on the law of energy conversation and the theory of radiation heat transfer, mechanism models of furnace temperature were set up for three zones of a 600 MW boiler before and after dual-scale low nitrogen retrofit, with which combustion characteristics in vertical space of the furnace was simulated using Simulink software. In addition, the temperature field and velocity field in horizontal space of the furnace were also simulated using Fluent software, while the mechanism of dual-scale low nitrogen combustion retrofit was analyzed comprehensively. Results show that the flow of primary air is in opposite direction to the secondary air due to the bias of primary air flow after retrofit, thus making the swirl region expanded in horizontal direction and shortened in vertical direction, resulting in increased combustion efficiency and lowered NOx emission in partial areas, but simultaneously increased inertia of combustion process and reduced adaptability to uploading conditions. © 2016, Editorial Department of Chinese Society of Power Engineering. All right reserved.


Li M.,Yantai Longyuan Electrical Power Technology Co. | Wang X.,Yantai Longyuan Electrical Power Technology Co. | Sun S.,Yantai Longyuan Electrical Power Technology Co. | Zhen X.,Yantai Longyuan Electrical Power Technology Co. | And 2 more authors.
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2015

Numerical simulation was conducted to the low NOx combustion retrofit for a 330MW subcritical opposed firing boiler, so as to study the influence of overfire air jet form on its penetration capability through high-temperature viscous flame in the furnace, the carbon burnout rate and the NOx emission under retrofit conditions, on the premise of same overfire air ratio, constant distance from top coal burner to the nozzle and of fixed nozzle area. Results show that the circular nozzle direct flow overfire air has the strongest penetration capability, followed by the rectangular nozzle direct flow overfire air, and the overfire air in the form of outer cyclone inner direct flow has the weakest penetration capability. Highest CO emission is generated under the condition with circular nozzle direct flow overfire air due to its lowest comprehensive level of covering area of jet roots on the horizontal cross section in the furnace and its lowest air layer thickness along flue gas flow path. Lowest unburned carbon exists in the fly ash in the over-fire air jet form of outer cyclone inner direct flow because of its high-intensity turbulent mixing effect during later jet period. The overfire air in three different jet forms discussed play little role in NOx emission. ©, 2015, Shanghai Power Equipment Research Institute. All right reserved.


Wang X.,Yantai Longyuan Electrical Power Technology Co. | Sun S.,Yantai Longyuan Electrical Power Technology Co. | Li M.,Yantai Longyuan Electrical Power Technology Co. | Liu X.,Yantai Longyuan Electrical Power Technology Co. | And 3 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2015

3-D full-scale steady numerical simulation technique was employed to study on low NOx combustion technological transformation of a 600 MW supercritical boiler with opposed wall swirling burners. Single burner was numerically calculation in advance for the sake of obtaining more realistic inlet boundary setting in the furnace simulation. In order to improve the calculation accuracy by means of undifferentiated connection of boundary condition between burner outlet and furnace inlet with actual spatial distribution of air and pulverized coal, user-defined functions (UDF) was compiled. Compared with past models, computing control domain was extended to whole flow and heat transfer region including boiler level gas flue and tail shaft flue. The results show that O2 concentration reaches wave crest at each centre cross-section of pulverized coal burner layers under baseline condition. Hence, NO concentration increases sharply when flue gas flows through each layer of pulverized coal burners. While the centre cross-sections of pulverized coal burner layers are at lower level in an O2 concentration cycle of fluctuation and adjacent CO concentration peaks with the combination of both annular reverse flow zone and center reflux zone under reconstructive condition, so NO concentration of flue gas in those regions decreases dramatically. Furthermore, this study shows that reasonable low NOx combustion technological transformation scheme exerts no adverse influence on surfaces heat transfer. © 2015 Chin. Soc. for Elec. Eng..

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