检索结果-南通市图书馆

Effect of fluidizing velocity on gas bypass and solid fraction in a dual fluidized bed gasifier and a cold model

在线全文

学校读者我要写书评

暂无评论

Particuology 2015年第1期13卷 58-65页

作者： Mook Tzeng Lim Woei-Lean Saw Shusheng Pang Department of Chemical and Process Engineering University of Canterbury Centre for Energy Technology School of Chemical EngineeringUniversity of Adelaide

Dual fluidized bed gasifiers （DFBG） are effective in producing nitrogen-free syngas from biomass. How- ever, to improve the gasifier performance, pressure drops and solid fractions within the DFBG system need to be controlled. In this study, the effects of varying the fluidizing velocity in the fast fluidized bed （FFB） on the pressure drops and the solid fractions in the system were investigated in a 100 kW DFBG and in a dual fluidized bed cold model （DFCM）. Based on the experimental results, empirical correlations were developed to predict the height-averaged solid fraction in the bottom section of the FFB. Accuracy and advantages of the correlations were analyzed. The correlation is useful for design and modeling of the DFBG systems where the height-averaged solid fraction is required to be determined.

关键词： cold model Hydrodynamics Steam gasification Dual fluidized bed

A cold model Aerodynamical Test of Air-Staged Combustion in a Tangential Firing Utility Boiler

在线全文

学校读者我要写书评

暂无评论

International Journal of Plant Engineering and Management 2007年第1期12卷 36-41页

作者： ZHANG Hui-juan HUI Shi-en ZHOU Qu-lan School of Energy and Power Engineering Xi＇an Jiaotong University Xi＇an 710049 P. R. China

The purpose of this paper is to present the flow field in the 300MW tangential firing utility boiler that used the Low NOx Concentric Firing System （LNCFS）. Using the method of cold isothermal simulation ensures the geometric and boundary condition similarity. At the same time the condition of self-modeling is met. The experimental results show that the mixture of primary air and secondary air becomes slower, the average turbulence magnitude the relative diameter of the tangential firing enlarges of the main combustion zone becomes less and when the secondary air deflection angle increases When the velocity pressure ratio of the secondary air to the primary air （p2/p1） enlarges, the mixture of the secondary air and the primary air becomes stronger, the average turbulence magnitude of the main combustion zone increases, and the relative diameter of the tangential firing becomes larger. Because the over fire air （OFA） laid out near the wall has a powerful penetration, the relative diameter of the tangential firing on the section of the OFA is very little, but the average turbulence magnitude is great. When the velocity pressure ratio of the OFA to the primary air POFA/p1 increases, the relative diameter of the tangential firing on the section of the OFA grows little, the average turbulence magnitude becomes larger and the penetration of the OFA becomes more powerful.

关键词： air-staged combustion concentric firing system cold model

Size analysis of slag eye formed by gas blowing in ladle refining

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2017年第3期24卷 243-250页

作者： Ning-ning Lv Liu-shun Wu Hai-chuan Wang Yuan-chi Dong Chang Su School of Metallurgical Engineering Anhui University of Technology Ma'anshan 243032 Anhui China Key Laboratory of Metallurgical Emission Reduction & Resources Recycling Ministry of Education Ma' anshan 243002 AnhuiChina

The formation of slag eye in a gas stirred ladle was studied through cold models and industrial trials. In the cold model,water and sodium tungstate solution were employed to simulate liquid steel,and silicon oil was employed to simulate slag. The simulation results revealed that the gas flow rate and bath height had strong effects on the slag eye size. In particular,the thickness of slag layer played a strong role in the slag eye size. In addition,the slag eye could not be formed when the thickness of the top layer was more than 4 cm in water-silicone oil ***,the section area of vessel had a great impact on the slag eye size. Industrial trials results showed a similar trend that the gas flow rate was very significant on the slag eye size. The predictions of the existing models showed larger predictions deviations compared with the experimental data. Moreover,a new model without fitting parameters was developed based on force balance and mathematical derivation,and verified by the experimental data. The new model provides the prediction with small deviations by comparing with the data acquired from cold models and industrial trials.

关键词： Slag eye cold model Industrial trial Gas blowing Ladle refining

Improvement of Impeller Blade Structure for Gas Injection Refining under Mechanical Stirring

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2014年第2期21卷 135-143页

作者： Yan LIU Zi-mu ZHANG Sano MASAMICHI Jun ZHANG Pin SHAO Ting-an ZHANG Key Laboratory of Ecological Utilization of Multi-metal Intergrown Ores of Ministry of Education School of Materials and MetallurgyNortheastern University Nagoya University

Abstract： The impeller blade structure for gas injection refining under mechanical stirring has been explored by water model experiments. A sloped swept-back blade impeller is＇proposed for the purpose. The central part of the impeller is disk- or plate-shaped, and the blades are fitted to the side of the disk or plate. In addition, a disk is put on the top side of the impeller blades. The impeller can strengthen the radial and downward flow between the blades and weaken the swirl flow in the zone above the impeller. These effects on flow phenomena are favorable for disintegration and wide dispersion of bubbles which are injected from a nozzle attached to the center of the underside of the impeller. In addition, the sloped swept-back impeller requires less power consumption. The impeller shaft should be placed away from the vessel center so as to disperse the injected bubbles widely in the bath under mechanical stirring even with unidi- rectional impeller rotation and without installing baffles. The number of gas holes in the nozzle and the direction of gas injection have a little effect on the bubble disintegration and dispersion in the bath. Highly efficient gas injection refining can be established under the conditions of proper impeller size, larger nozzle immersion depth, larger eccen- tricity and rotation speed of the impeller. The sloped swept back blade impeller can decrease the power consumption and vet improve the bubble disintegration and wide dist^ersion in the bath.

关键词： gas injection refining cold model eccentric mechanical stirring impeller structure power consump-tion bubble disintegration bubble dispersion