Wu Y.,Guangdong Yudean Group Co. |
Wen Z.,Guangdong Power Grid Corporation |
Shen Y.,Guangdong Power Grid Corporation |
Fang Q.,Huazhong University of Science and Technology |
And 2 more authors.
Advanced Materials Research
A computational fluid dynamics (CFD) model of a 600 MW opposed swirling coal-fired utility boiler has been established. The chemical percolation devolatilization (CPD) model, instead of an empirical method, has been adapted to predict the nitrogen release during the devolatilization. The current CFD model has been validated by comparing the simulated results with the experimental data obtained from the boiler for case study. The validated CFD model is then applied to study the effects of ratio of over fire air (OFA) on the combustion and nitrogen oxides (NOx) emission characteristics. It is found that, with increasing the ratio of OFA, the carbon content in fly ash increases linearly, and the NOx emission reduces largely. The OFA ratio of 30% is optimal for both high burnout of pulverized coal and low NOx emission. The present study provides helpful information for understanding and optimizing the combustion of the studied boiler. © (2012) Trans Tech Publications, Switzerland. Source
Zheng K.,Jilin University |
Zheng K.,Jilin Institute of Architecture and Civil Engineering |
Zhao D.,Jilin University |
Zhang X.,Guangdong Yudean Group Co.
Hanjie Xuebao/Transactions of the China Welding Institution
Dissimilar metal welds between SA335P91 and 12Cr1MoV ferritic heat-resistant steels are widely applied in the main steam pipe and the reheater on boiler heating surface for the supercritical (SC) and ultra-supercritical (USC) thermal power units in China. The characteristics of microstructure and weldability of two steels were described, and the welding mechanism for dissimilar metal weld between two steels was investigated. Through theoretical analysis and experiments, the main factors in dissimilar metal welding that resulted in hot and cold cracks, decrease of toughness, embrittlement and type IV softening cracking tendency were determined. Corresponding technological methods and heat treatment procedures to prevent the above defects were proposed and solid joints were achieved. Source
Zhu Z.-F.,Guangdong Yudean Group Co. |
Wang L.-P.,Huazhong University of Science and Technology |
Qi H.,Huazhong University of Science and Technology |
Zhang C.,Huazhong University of Science and Technology |
And 4 more authors.
Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology
Particulate matter from coal combustion is one of the most main atmospheric pollutants in urban China currently. It has caused serious damage to the environment and human health. A 3012H type automatic smoke-dust (flue-gas) monitor was used to collect PMs in front of the ESP of 1# boiler in Shajiao C power plant in Humen. The influence of boiler load and coal type on the emission characteristics of the fly ash was studied. The particle size distribution, chemical composition, mineral constituent and morphology characteristics of the fly ash were also analyzed. The results indicate that the fractions of PM1 and PM2.5 increase with the rising of boiler load, however, the concentration of the total smoke-dust decreases. The level of PM1 and PM2.5 becomes higher when the blending ratio of Yitai coal increases. The coal is easy to form coal cells containing molten spherules when burned in a high load boiler, and to form porous cenospheres when burned in a low load boiler. The mineral component of the ashes collected from different situations is similar. Source
Hong R.-K.,Guangdong Yudean Group Co. |
Shen Y.-L.,Guangdong Power Grid Corporation |
Zhao Z.-F.,Huazhong University of Science and Technology
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering
Emission characteristics of CO and NOx from a 600 MW supercritical boiler with burners arranged in front and back walls were studied by both field experiment and numerical simulation. Results show that the CO concentration in the flue gas is within 500-2500 mg/m3. The turning point of NOx emission appears when the excess air coefficient α1 is within 0.86-0.90 in main burning area, higher than the designed α1 (0.80) for low NOx emission, in which case the corresponding ratio of overfire air to secondary air is about 27%-32%. NOx emission characteristics of the boiler are influenced by the design of its HT-NR3 burner for low NOx emission, indicating a negative correlation to CO emission. At the load of 600 MW and a constant total air volume, the rise of overfire air ratio from 32% to 49% would result in a significant reduction of CO concentration and combustible contents in fly ash, but an increase of NOx emission, when the influence of oxygen content on CO and NOx emission weakens obviously, which may raise the possibility of high-temperature corrosion on side walls in the main burning area. Source
Cai Q.,South China University of Technology |
Wen F.,Zhejiang University |
Ding J.,Guangdong Yudean Group Co. |
Hong H.,Guangdong Yudean Group Co. |
Li C.,Guangdong Yudean Group Co.
Dianli Xitong Zidonghua/Automation of Electric Power Systems
In view of the electricity market, a comprehensive multi-objective reserve bidding model is developed considering the factors of economics, reliability and emissions. To describe the supply reliability associated with reserves, the expected reserve deficiency is defined. They can be used to distinguish the capability of a generator and that of an interruptible load in providing the reserve service. On this basis, a two-stage algorithm is presented to solve the multi-objective bidding model. Firstly, the improved multi-objective particle swarm optimization algorithm is employed to find the Pareto solutions of the multi-objective bidding model which minimizes the reserve capacity cost, the expected reserve deficiency and the emissions separately. Then, the entropy weight decision-making method is used to evaluate the Pareto solutions, and obtains the optimal reserve allocations among the bidders. Finally, an example of the electricity market with 12 bidders including generators and interruptible loads is employed to illustrate the essential feature of the developed model and its efficiency. © 2012 State Grid Electric Power Research Institute Press. Source