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158 results on '"Wang, Huajian"'

151. New Fuel Air Control Strategy for Reducing NOxEmissions from Corner-Fired Utility Boilers at Medium–Low Loads

Author

Zhao, Sinan, Fang, Qingyan, Yin, Chungen, Wei, Tongsheng, Wang, Huajian, Zhang, Cheng, and Chen, Gang

Abstract

Due to the rapidly growing renewable power, the fossil fuel power plants have to be increasingly operated under large and rapid load change conditions, which can induce various challenges. This work aims to reduce NOxemissions of large-scale corner-fired boilers operated at medium–low loads. The combustion characteristics and NOxemissions from a 1000 MWecorner-fired tower boiler under different loads are investigated experimentally and numerically. A new control strategy for the annular fuel air is proposed and implemented in the boiler, in which the secondary air admitted to the furnace through the air annulus around each coal nozzle tip is controlled by the boiler load, instead of being controlled by the output of the connected mill as commonly used in this kind of power plant. Both the experimental and simulation results show that the new control strategy reduces NOxemissions at the entrance of the selective catalytic reduction (SCR) system by about 20% at medium–low loads, compared to those based on the original control. The new control strategy has also been successfully applied to two other corner-fired boilers to achieve a significant NOxemission reduction at partial loads. In all three applications, no negative effect on the combustion and steam temperature characteristics of the boilers is observed.

Published
2017
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155. Measurements on flame temperature and its 3D distribution in a 660 MWe arch-fired coal combustion furnace by visible image processing and verification by using an infrared pyrometer

Author

Wang Huajian, Fang Qingyan, Huang Zhi-feng, Lou Chun, Wang Dundun, Sun Yipeng, Zhou Huai-chun, and Luo Zixue

Subjects
Materials science, Applied Mathematics, Nuclear engineering, Coal combustion products, Combustion, Adiabatic flame temperature, law.invention, Ignition system, law, Measuring instrument, Emissivity, Energy source, Instrumentation, Engineering (miscellaneous), Pyrometer
Abstract

In order to verify the 3D temperature distribution of combustion in large-scale, coal-fired boiler furnaces visualized through a visible flame image processing system, a carefully calibrated portable flame temperature measuring system adopting the same flame image processing technique was developed, which is more convenient for industrial flame measurements. Furthermore, the temperatures and emissivities measured by the portable system were compared with the results by an infrared pyrometer which was used to measure the equivalent blackbody temperatures of the flames. The relative differences of the predicted temperatures and emissivity for a blackbody furnace by the portable system are less than 1% and 3%, respectively, showing a good accuracy for its application in the combustion industry. The equivalent blackbody temperatures deduced from the flame temperatures and emissivities measured by the portable system from 12 flame-observing ports in a 660 MWe arch-fired boiler in three horizontal sections at different elevations were compared with those measured by the infrared pyrometer. The relative differences are less than 7%, an acceptable agreement for measurements in the case of a coal-fired furnace. The cross-section-averaged temperatures deduced from the 3D temperature distribution acquired by the visualizing system were verified by those measured by the portable flame measuring system, and the two sets of results matched each other reasonably. This revealed that the coal combustion in the furnace was suffering from seriously delayed ignition of coal, leading to a lower efficiency of fuel utilization.

Published
2009
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156. Improved Extend Kalman particle filter based on Markov chain Monte Carlo for nonlinear state estimation.

Author

Wang, Huajian

Abstract

Considering the problem of poor tracking accuracy and particle degradation in the traditional particle filter algorithm, a new improved particle filter algorithm with the Markov chain Monte Carlo (MCMC) and extended particle filter is discussed. The algorithm uses Extend Kalman filter to generate a proposal distribution, which can integrate latest observation information to get the posterior probability distribution that is more in line with the true state. Meanwhile, the algorithm is optimized by MCMC sampling method, which makes the particles more diverse. The simulation results show that the improved extend Kalman particle filter solves particle degradation effectively and improves tracking accuracy. [ABSTRACT FROM PUBLISHER]

Published
2012
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158. The influence of cigR gene on the pathogenicity of Salmonella paratyphi A in vitro and in vivo.

Author

Yin J, Wang L, Shen R, He J, Li S, Wang H, and Cheng Z

Subjects
Animals, Mice, Humans, Virulence genetics, THP-1 Cells, Macrophages microbiology, Mice, Inbred BALB C, Female, Gene Deletion, Salmonella paratyphi A genetics, Salmonella paratyphi A pathogenicity, Paratyphoid Fever microbiology, Bacterial Proteins genetics, Bacterial Proteins metabolism, Virulence Factors genetics
Abstract

Salmonella Paratyphi A is the causative agent of paratyphoid fever A which is a serious threat to human health in many countries. The cigR gene located in Salmonella pathogenicity island 3 is a type III secretion system 2 effector gene. However, the influence of cigR gene on the pathogenicity of Salmonella Paratyphi A remains unclear. Here, a cigR gene deletion mutant of Salmonella Paratyphi A was constructed and its pathogenic changes were also evaluated. It was found that both the growth and biochemical features have not changed after the loss of cigR, but the absence of cigR significantly enhanced the replication and/or survival ability in phorbol-12-myristate-13-acetate (PMA)-differentiated human macrophage THP-1 cells and in mouse; the proliferative activity and apoptosis of PMA-differentiated THP-1 cell were significantly decreased and increased, respectively, after the lack of cigR gene; and the mutant showed increased virulence to a mouse infection model by decreased half-lethal dose (LD50) value and enhanced the proliferation ratio of bacteria in vivo. These results demonstrated that CigR is an anti-virulence factor and plays an important role in the pathogenicity of Salmonella Paratyphi A., (© The Author(s) 2024. Published by Oxford University Press on behalf of FEMS.)

Published
2024
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