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Zhao H.,Zhejiang University | Yu H.,Zhejiang University | Yang J.,Zhejiang University | Zhu S.,Zhejiang Provincial Energy Group Co. | And 3 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2014

Improving the medium speed mill outlet temperature has significant economy for power plant. The safety of the mixing process of gas-solid is the key factor to set the outlet temperature. The dynamic heat transfer characteristics of gas-solid in HP863 medium speed mill was studied with numerical simulation and performance tests. The temperature fields in the mill were analyzed by numerical simulation first, and then the critical region of heat transfer was obtained. The practical temperature fields inthe critical region were measured on a running mill. The comprehensive results show that the intense heat transfer concentrate in a rather small region after the mixing of hot air and pulverized coal. The gas-solid mixed temperature decrease 100°C within about 60mm and 0.001s. The mixed temperature reduce to mill outlet temperature within 240mm after the mixing of hot air and pulverized coal. © 2014 Chinese Society for Electrical Engineering.

Lin Z.-M.,Zhejiang University | Chen Y.,Zhejiang Provincial Energy Group Co. | Wang Z.-H.,Zhejiang University | Zou X.-B.,Guangdong Yudean Group Co. | And 4 more authors.
Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology | Year: 2014

3 low rank coals were dewatered and upgraded by hydrothermal process at 200, 250 and 300 °C. Nitrogen adsorption measurements and FT-IR spectra of the parent and upgraded coals were performed to get the change of pore distribution and functional groups. After hydrothermal treatment, the average pore diameter and specific pore volume drop rapidly. The content of hydroxyl and carboxyl decreases and the cyclized degree increases. The monocyclic aromatics change into polycyclic aromatics and the organic matter in coal is gradually mature, which reflect the coal rank becomes higher. Then, rapid pyrolysis were carried out in a CDS5000 Pyroprobe accompanied by a GC/MS at 5 000 °C/s, 1 000 °C to investigate the release characteristics of macromolecular volatile products of these coals. With the final reaction temperature increasing, the content of aliphatic hydrocarbon, acids and phenols decreases, that of aromatic hydrocarbon increases. The esters in coals have no obvious variation law.

He Y.,Zhejiang Provincial Energy Group Co. | Li B.,Zhejiang Zheneng Zhongmei Zhoushan Coal and Power Co. | Zhu Q.,Zhejiang Zheneng Taizhou No. 2 Power Plant | Liu J.,Jiangsu Ligang Electrical Power Co. | Chen Z.,Zhejiang Zheneng Zhongmei Zhoushan Coal and Power Co.
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2013

Coal-saving benefits of the flue gas waste heat recovery system for purposes of heat supply or condensate water heating were studied, based on the first and second law of thermodynamics and the heat balance diagram of steam turbine, while a comparison made between theoretical values of calculation examples and performance test data of actual engineering projects. Results show that the appropriate way for calculating the coal saving benefits is to firstly calculate the waste heat recovered from flue gas, then figure out the heat balance diagram for obtaining new heat rate of steam turbine, and finally calculate the saving value of coal consumption by the formula given out. To improve the coal-saving benefit, it is recommended to economize the steam as much as possible at bleed points of higher stages, but not to simply reduce the flue gas temperature, during performance design of flue gas waste heat recovery systems.

Zhang Q.,Zhejiang University | Zhang Q.,Zhejiang Provincial Energy Group Co. | Zhang X.-X.,Zhejiang University | Zhang X.-X.,China University of Petroleum - East China | And 5 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2013

To clarify the heterogeneous reduction reaction mechanisms, NO chemisorptions on several char models with different configurations were investigated using density functional theory in this paper. Char models and NO adsorption products were optimized at B3LYP/6-31G(d) level. The results show that NO chemisorption on the surface of pure carbon is exothermic. NO chemisorptions on nitrogen-containing char with the formation of N-N bond are exothermic processes. It is exothermic when N-O bond is formed with NO chemisorption on nitrogen-containing char with zigzag or "hole" armchair configuration in side-on mode. Chemisorption of NO on nitrogen-containing char with "shoulder" armchair configuration in side-on mode is endothermic. NO molecules prefer to chemisorb on pure carbon with zigzag configuration. Chemisorption of NO on nitrogen-containing char with the formation of N-N bond is preferred.

Yang J.,Zhejiang University | Fan L.,Zhejiang University | Zhao H.,Zhejiang University | Mou W.,Zhejiang Provincial Energy Group Co. | And 3 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2014

Different control programs of flue gas temperature and selective catalytic reduction (SCR) economizer were designed and studied to reduce ammonia slip rate and relieve air preheater fouling problem. A 300 MW unit was selected for the study. The boiler thermal calculation results indicate that through the joint arrangements between the high temperature flue gas bypass and SCR economizer, the SCR inlet flue gas temperature could be regulated to nearly 340°C under the lowest flue gas temperature condition with maximum 20% bypass flue gas ratio and 40% the original economizer area of SCR economizer. While, under the highest flue gas temperature condition, the SCR inlet flue gas temperature would not be regulated, and the exhaust gas temperature could be decreased 6.1°C. In this way, the highly efficient operation of catalyst at 340°C or more of SCR inlet flue gas temperature and variation of exhaust gas temperature in much smaller and more optimal range are almost completely achieved under all operating conditions. If the annual average load was 75%, the average exhaust gas temperature would approximately be dropped 5.2°C and the standard coal consumption decreased was nearly 1 g/(kW·h). © 2013 Chinese Optics Letters.

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