Study of the reaction mechanism for preparing powdered activated coke with SO_(2)adsorption capability via one-step rapid activation method under flue gas atmosphere

In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction mechanism is summarized.Results indicate that the reaction process of this method can be divided into three stages:stage I is the rapid release of volatiles and the rapid consumption of O_(2),primarily occurring within a reaction time range of 0-0.5 s;stage II is mainly the continuous release and diffusion of volatiles,which is the carbonization and activation coupling reaction stage,and the carbonization process is the main in this stage.This stage mainly occurs at the reaction time range of 0.5 -2.0 s when SL-coal is used as material,and that is 0.5-3.0 s when JJ-coal is used as material;stage III is mainly the activation stage,during which activated components diffuse to both the surface and interior of particles.This stage mainly involves the reaction stage of CO_(2)and H2O(g)activation,and it mainly occurs at the reaction time range of 2.0-4.0 s when SL-coal is used as material,and that is 3.0-4.0 s when JJ-coal is used as material.Besides,the main function of the first two stages is to provide more diffusion channels and contact surfaces/activation sites for the diffusion and activation of the activated components in the third stage.Mastering the reaction mechanism would serve as a crucial reference and foundation for designing the structure,size of the reactor,and optimal positioning of the activator nozzle in PAC preparation.

“公共管理学”课程思政建设路径及其实施保障

“公共管理学”作为公共管理类专业的核心课程,在新时代加强课程思政建设,讲好中国公共管理故事,构建中国之治的知识体系和话语体系,显得尤为重要和迫切。“公共管理学”课程思政建设是一项系统工程,要以师资队伍建设为抓手,深入挖掘课程思政元素,完成“课程承载思政,思政寓于课程”的课程思政内容体系建设,从宏观和微观层面探索多维协同育人的课程思政建设路径和科学合理的保障措施,以实现“公共管理学”课程教学在知识传授、能力培养和价值塑造方面的综合育人目标。

Mechanism Research on PM2.5 Charging, Precipitation in High Electrostatic Field

In this project, some charged characteristics, and analysis of precipitated PM2.5 in high electrostatic field were calculated based on theories and experiments. The connection between the charge amount and the additional electric field intensity caused by the wet flexible collectors was studied to reveal the mechanism of charging enhancement of PM2.5 on flexible collectors. Some explanation about the wet ability of collectors and the current density enhancing the precipitation process was proposed in this project. Simultaneously, the results shows that both gas treatment time and applied voltage have an important influence on particle collection, and the minor factor was initial concentration.

Wetting Characterization of Hybrid Coatings Deposited on Carbon Steel Collectors for Hydrophilic Modification

The additional anticorrosive coating and hydrophilic layer of glass fiber cloth (GFC) deposited on the carbon steel sheet (CSS) was experimented and the surface wetting characteristic of the hydrophilic modified collection electrode was investigated under single strand feed water condition. The distilled water was selected as the working fluid. The influence of Reynolds number on the surface wetting characteristic parameters and those parameters at different temperatures were specifically studied. The results indicate that the GFC surface with loose glass fiber bundles reveals remarkable surface wetting characterizations. The saturated liquid holdup of this surface is 8 - 10 times more than that of the CSS surface;the surface flowrate value is 6 - 8 percent of that of the CSS surface;the film rate of this surface is 28 - 32 times more than that of the CSS surface;the average film thickness is between a third and a half of the value of the CSS surface. Good agreement is achieved between the WESPs working temperature and the experimental temperature range with remarkable wetting characterizations that provides a theoretical basis for the industrial application. Not satisfactorily, the hydrophilic modification surface is not able to survive high temperature.

Research on Characteristic of Fe²⁺/S₂O^2-<sub style="margin-left:-7px;">8</sub>Composite CaO Synergetic Conditioning for Municipal Sludge

For the problem as high energy consumption and sludge increment during the municipal sludge management process with advanced oxidation technology of sulfate radical, the Fe2+/S2O2-8 composite CaO reaction system was set up. Meanwhile, systematical studies had been carried out for coordinated conditioning of municipal concentrated sludge. The scientific process parameters were determined with the help of sludge capillary suction time, sewage sludge moisture content and other core indicators and the effect of traditional polyacrylamide flocculation method, Fenton method and activated persulfate method were compared. The results showed that in the neutral concentrated sludge conditioning, there were outstanding advantages for Fe2+/S2O2-8 composite CaO reaction system compared with Fenton, CPAM, and SO-4 methods and the optimal parameters for dosage were as follows: Fe2+/S2O2-8: 80 - 120 mg·g-1 DS, n(Fe2+):n(SPS) = 0.8:1, CaO: 200 mg·g-1 DS. To achieve similar performance index, the dosage of Fe2+ per ton for sludge could be reduced by 20%, the loss rate for iron in filtrate was 0.5%, dewatering of sludge by suction filtration was within 50 s and the moisture content for dewatering cake was 53.7%, which significantly improved the economy and practicability of SO-4 advanced oxidation technology, and the results were expected to form a useful supplement to the popularization and application of SO-4 advanced oxidation technology.

Study on sulfur migration in activated carbon adsorption-desorption cycle: Effect of alkali/alkaline earth metals

Activated carbon(AC)has been widely used in the removal of SO_(2) from flue gas owing to its well-developed pore structure and abundant functional groups.Herein,the effect of alkali/alkaline earth metals on sulfur migration was investigated based on the dynamic adsorption and temperature programmed desorption experiment.The adsorption and desorption properties of six types of AC(three commercial and three laboratory-made)were carried out on a fixed-bed experimental device,and the physical and chemical properties of samples were determined by X-ray fluorescence,X-ray diffraction,scanning electron microscopy/energy dispersive X-ray,and X-ray photoelectron spectroscopy analysis.The experimental results showed that the adsorbed SO_(2) cannot be completely desorbed by increasing the regeneration temperature(350-850℃),while the SO_(2) fixed in the AC combines with the Ca-based minerals in the ash to form a stable sulfate.For different samples,higher ash content,higher CaO content in the ash and a more developed pore structure lead to a higher SO_(2) fixation rate.Moreover,the multiple adsorption-desorption cycles experiment showed that the effect of SO_(2) fixation is mainly reflected in the first cycle,after which the adsorption and desorption amount are approximately the same.This study elucidates the effect of alkali/alkaline earth metals on the adsorption-desorption cycle of AC,which provides a deeper understanding of sulfur migration in the AC flue gas desulfurization process.