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Gao M.,Tsinghua University | Gao M.,North China Electrical Power University | Yue G.,Tsinghua University | Lei X.,Sichuan Baima CFB Demonstration Power Plant Co. | And 3 more authors.
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2015

By analyzing the dynamic characteristics, energy balance, burning carbon and main steam pressure control of supercritical circulating fluidized bed (CFB) boilers, a soft-sensing model was established based on mechanism analysis by reasonably setting relevant key parameters, so as to calculate the amount of burning carbon storage and heat storage in the furnace, and thus obtaining the heat signal in the boiler. The control strategy of energy balance was then applied in the main steam pressure control of a supercritical CFB boiler. Results show that the method can help to stabilize the main steam pressure, enhance the adaptability to load change and improve the control quality of the unit, proving both the model established and the method proposed to be effective. ©, 2015, Shanghai Power Equipment Research Institute. All right reserved.


Gao M.,Tsinghua University | Gao M.,North China Electrical Power University | Yue G.,Tsinghua University | Lei X.,Sichuan Baima CFB Demonstration Power Plant Co. | And 3 more authors.
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2014

For the instable and time delay process of in-furnace desulfurization in circulating fluidized bed (CFB) boiler, a specific "active limestone" state monitoring model was set up to simulate the desulfurization process, while a method for optimization of the n(Ca)/n(S) was suggested according to the balance of "active limestone", and simultaneously a SO2 emission prediction model was proposed based on the coal feed rate, air flow rate and in-furnace active limestone mass, with which simulation tests were carried out to a 600 MW supercritical CFB boiler using actual operation data. Simulation results prove the prediction model to be effective, and the optimization of n(Ca)/n(S) based on the model helps to improve the stability of SO2 emission.


Lu J.,Chongqing University | Lu X.,Chongqing University | Wang H.,Chongqing University | Wang Q.,Chongqing University | And 7 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012

Gas concentrations of the external circulation loop in the imported 300 MW circulating fluidized bed (CFB) boiler were measured by self-made probes to investigate the combustion characteristics of the cyclones and external heat exchangers (EHEs). Results implied that there was significant post combustion phenomenon in the boiler's external circulation loop, and most of the combustion was from the cyclones. The flue gas temperature at the cyclone outlet could be 135°C higher than that at the cyclone inlet. The ratio of the O 2 consumption in the cyclone to that of the whole combustion process in the boiler could be as high as 12%. With regard to the EHEs, the inside combustion phenomenon was not as severe as that in the cyclones. Obvious differences of gas concentrations were observed at the outlet between those EHEs with different functions. The O 2 consumption of the furnace temperature adjusting EHEs could be twice that of the reheat steam temperature adjusting EHEs. These experimental results can provide information for the design of mew CFB boilers. © 2012 Chin. Soc. for Elec. Eng.


Yue G.,Tsinghua University | Lv J.,Tsinghua University | Yang H.,Tsinghua University | Su H.,Dongfang Boiler Group Co. | And 4 more authors.
CFB-11: Proceedings of the 11th International Conference on Fluidized Bed Technology | Year: 2014

The world's largest 600MW supercritical circulating fluidized bed (SCCFB) boiler was successfully put into operation with the full load in the end of March 2013 and passed commissioning test in middle April, 2013 in Baima Power Plant in Sichuan, China. This paper introduces the key design and tested performance of the boiler. The main steam parameters of the SCCFB boiler are 25.4MPa and 571oC/569oC. The structure of the furnace is of pant-leg type with two sets of air distributors, 6 steam cooled cyclones and 6 external heat exchangers (EHEs). The media flow rate was chosen as lower than 800kg/m2.s, which was proved to be safe by calculation and laboratory test at Tsinghua University. Some laboratory experiments and the results regarding to the gas solid hydrodynamics in the ultra-high furnace, the mal-distribution of gas solid flow among the multiple parallel cyclones and the system stability analysis in the large furnace especially on bed material balance between the two pant-legs are introduced. In addition, some industrial measurements on the large CFBs, which are used to calculate the 3D heat transfer coefficient distributions, are reported. Besides, the development of the auxiliary systems, such as the ash cooler with high capacity, in-furnace desulfurization system and the 600MW dynamic simulator are introduced. At last, some test results of the performance of the SCCFB boiler are given and discussed. It was found the deviation of the bed temperatures between the design and the operation was less than 5oC. The lateral temperature distribution along the lateral membrane wall was predicted successfully by the model calculation.


Gao M.-M.,North China Electrical Power University | Liu J.-Z.,North China Electrical Power University | Niu Y.-G.,North China Electrical Power University | Lei X.-J.,Sichuan Baima CFB Demonstration Power Plant Co. | And 2 more authors.
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2013

To overcome the deficiency of delayed heat release signals from circulating fluidized bed (CFB) boiler, a method was put forward for calculation of the heat release and carbon residue by using easily measured signals of the combustion process. The specific way is to firstly divide the combusion system into dense phase area, dilute phase area and adiabatic cyclone separator area, then calculate the combustion share in adiabatic cyclone separator area based on materials mass and heat balance model, and finally build up carbon residue model by mechanism analysis and heat release model according to carbon residue and air volume. Based on experimental data of a 300 MW CFB boiler, and using extended Kalman filter technology, the in-furnace carbon residue and heat release were calculated respectively at loads of 285 MW and 200 MW, of which the results were compared with relevant literature data. Results show that the calculated results basically agree with relevant literature data, proving the model to be accurate and reasonable.


Xia Y.-Q.,Southwest University of Science and Technology | Yan Y.,Southwest University of Science and Technology | Hu Z.-H.,Southwest University of Science and Technology | Hu C.-H.,Sichuan Baima CFB Demonstration Power Plant Co Ltd | Lei X.-J.,Sichuan Baima CFB Demonstration Power Plant Co Ltd
Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology | Year: 2012

The pozzolanic and self-cementitious properties of CFBC fly ash with various chemical activators were investigated. The effect of different chemical activators and their different combinations on the mechanical properties of CFBC fly ash was evaluated based on the criteria of 7 d and 28 d compressive strengths of CFBC fly ash. Meanwhile, the influence of chemical activators on the early hydrating process and hydrated products of CFBC fly ash were analyzed with isothermal calorimeter method, XRD and IR. The results show that different activators obviously affect the strength of hardened CFBC fly ash paste and the degree of impact in order is as follows: lime>sodium silicate>TEA>Na2SO4; the addition of Na2SO4 promotes the dissolution of anhydrite and increases its hydration rate, composite activation of Na2SO4and TEA can solve the question that compressive strengths of CFBC fly ash with adding Na2SO4 increases slowly; the addition of lime significantly improves the activity of CFBC fly ash; the combination of four activators mentioned above are recommended to use for increasing the activity of CFBC fly ash, resulting into the 7 d and 28 d compressive strength of the mortar is up to 7 MPa and 22 MPa, respectively.


Wang H.,Chongqing University | Lu X.,Chongqing University | Zhang W.,Sichuan Baima CFB Demonstration Power Plant Co. | Wang Q.,Chongqing University | And 6 more authors.
Applied Thermal Engineering | Year: 2015

On the basis of measurements on the fluidized bed heat exchanger (FBHE) of a 300 MW lean-coal-fired circulating fluidized bed (CFB) boiler under different thermal loads and numerical calculation for steam mass flow rate distribution inside the high temperature reheater (HTR) tube panels, the ash-side heat transfer coefficient distribution along the ash movement direction inside the FBHE was obtained in this paper. A cell model with energy and material balances was also developed for the FBHE. The measured and calculated results indicate that the post-combustion phenomenon exists in the FBHE. The ash-flow movement inside the FBHE has an important impact on the bed-to-tube heat transferring process. Specifically, along the ash moving direction, steam temperature at the outlet of corresponding tube panel decreases gradually, as well as the local ash-side heat transfer coefficient. These results can provide referential materials for design and operation of the FBHE in large-scale CFB boilers. © 2015 Elsevier Ltd. All rights reserved.


Sun J.,National School of Technology | Wang Z.,Tsinghua University | Cao W.,National School of Technology | Wu H.,Tsinghua University | And 3 more authors.
Flow, Turbulence and Combustion | Year: 2013

An improved two particle sizes numerical model based on a uniform size model was established to investigate the influence of the average particle size on bed-inventory overturn inside a pant-leg circulating fluidized bed (CFB). The new model successfully simulated the dynamic performance of a pant-leg CFB that as average particle size shrank, the pant-leg CFB tended to overturn, while the uniform size model showed a contradicted trend. The success was attributed to the difference of the flow pattern with different particle size. The smaller particles tend to stay the upper furnace after fluidized by the primary air flow while the larger particles tend to fall back to the bottom soon after being carried to upper furnace by the primary air flow and smaller particles. As pointed out in our previous work, the lateral mass transfer resulted in a lateral pressure difference at the upper finance and inhibited further lateral mass transfer, which was regarded as a self-balancing process. The quick fall down of the large particles somehow weaken the lateral pressure different built-up at the upper furnace. Therefore, as the average particle size shrink, the weaken effect of the large particles on self-balancing ability of the pant-leg CFB increase, resulting a more tendency for bed-inventory overturn. It was such a characteristic behavior of the large particles, which was neglected in the uniform particle size model, caused the difference between the results of the two models described above. © 2013 Springer Science+Business Media Dordrecht.


Wu H.,Tsinghua University | Sun J.,Beihang University | Wang Z.,Tsinghua University | Li Z.,Tsinghua University | And 3 more authors.
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2014

Based on two-phase flow granular dynamics, a two-dimensional CFD numerical model was developed to investigate the impacts of bed inventory and air distributor resistance on the bed inventory overturn process in circulating fluidized bed with pant-legs. Results show that with the rise of bed inventory, the lateral solid flow rate rises, resulting in increased possibility of bed inventory overturn; whereas with the rise of air distributor resistance coefficient, the lateral solid flow rate drops, resulting in reduced possibility of bed inventory overturn. These phenomena can be explained by the mechanism of positive and negative feedback. The pressure drop ratio of air distributor and bed inventory may serve as an important parameter to evaluate the self-balance ability of furnace with pant-legs. © 2014, Editorial Department of Chinese Society of Power Engineering. All right reserved.


Gao M.-M.,North China Electrical Power University | Liu J.-Z.,North China Electrical Power University | Gag M.-S.,North China Electrical Power University | Yang S.-M.,Sichuan Baima CFB Demonstration Power Plant Co. | And 2 more authors.
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2012

To study the influence of the amount of return materials on bed temperature of related CFB boiler, a control model has been established for the return materials in ash recycling system based on compensatory fuzzy neural network (CFNN), with which a simulation study has been carried out by taking the temperature change and temperature variation rate as the input variables, and the return air flow as output variable. Comparison results between CFNN controller and conventional controller show that the adaptability of the former one to parameter change is obviously stronger than the latter one, which therefore may serve as a reference for control optimization of ash recycling systems.

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