Formation and Growth Behavior Analysis of Slagging Rings in Rotary Kiln-Type Hazardous Waste Incineration Systems

Rotary kiln incineration technology has the advantages of strong material adaptability and a simple treatment process and has been widely used in hazardous waste treatment. However, the actual incineration process has caused problems such as ring formation in the treatment system due to the lack of research on the slagging mechanisms. In this paper, slagging phenomena occurring in the second half of the rotary kiln, the exit flue of the secondary combustion chamber, and the wall of the quench tower are analyzed and discussed in detail through characterization methods. The results indicate that the adhesion of low-melting alkali metal salts on the refractory surface in the second half of the rotary kiln is the key factor in forming the initial slagging layer. In the growth process of the slagging ring, the formed liquid phase can bond incineration residues of different sizes together and form a dense embryo body through liquid phase sintering. The deposition and solidification of molten/semi-molten fly ashes cause slagging formation in the exit flue of the secondary combustion chamber. The slagging phenomenon occurring in the inner wall of the quench tower belongs to the "crystalline-coalesce-hardening " process of the inorganic salts precipitating out of the high-salt wastewater

The oxidation of NH_3/CO/O₂/H₂O system in a plug flow reactor: Experimental and kinetic modeling study

Ammonia, as a carbon-free fuel, is easier to store and transport than hydrogen. Due to the high ignition energy and low reactivity of ammonia, adding hydrogen or carbon-based fuels as combustion aids may improve the ignition and burnout of ammonia. CO is an important intermediate product in the co-combustion process of ammonia and carbon-based fuels. Research on NH3/CO co-combustion will further promote the application of such co-fuel in propulsion systems and power generation. In this work, experimental results were supplemented with novel flow reactor results on the effect of NH3 on CO oxidation in the absence of NO, and explained based on a detailed chemical kinetic model. The effects of temperature (1023-1223 K), NH3 concentration (250-1500 ppm), and water content (1 %-10 %) on CO oxidation, NH3 conversion, and NO generation were analyzed. In the NH3/CO system, the properties of CO always dominate. As the NH3 content increases, NH3 gradually inhibits the oxidation of CO by seizing free radicals (O, H, OH) and converting into NH2. NH2 further interacts with free radicals to convert into NH or HNO, and ultimately into NO. An increase in temperature will decrease the release of NO and CO and gradually decrease the conversion of NO from NH3. However, ammonia concentration had little effect on the ratio of ammonia conversion to NO. When H2O increases from 1 % to 2 %, it has a significant inhibitory effect on the production of NO and promotes the oxidation of CO. When the water concentration increases from 5 % to 10 %, the inhibitory effect reaches saturation. The present work evaluates the amine subset of the reaction mechanism under the studied conditions and provides experimental data under different NH3/CO ratios, which can be used to construct and verify the reaction mechanism of mixed fuels of carbon-based fuels and ammonia

一种工业废盐高效净化系统

本实用新型公开了一种工业废盐高效净化系统，包括鼓泡系统、分离系统、催化燃烧系统；鼓泡系统上部连接用于送入工业废盐的管道；下部接入用于输送被初步净化的工业废盐的管道；内部设有专门用于废盐颗粒流化的设备；顶部与分离系统连接；底部与催化燃烧系统连接；鼓泡系统对工业废盐原料进行鼓泡流化；分离系统对裹挟着工业废盐中析出的有机气体和部分粉尘颗粒物的气体进行分离；催化燃烧系统对分离后的气体进行催化燃烧处理；催化燃烧处理后的气体返回鼓泡系统构成循环。本实用新型不仅能将工业废盐中的TOC降至30mg/kg以下，而且还可以利用TOC催化燃烧放出的热量，在一定程度上降低能源的消耗，保证设备的稳定、高效运行

一种利用催化燃烧工业处理循环气高效净化工业废盐的方法

本发明公开了一种利用催化燃烧工业处理循环气高效净化工业废盐的方法,包括以下步骤：加热的气体对鼓泡系统中的工业废盐原料进行鼓泡流化,然后裹挟着工业废盐中析出的有机气体和部分粉尘颗粒物进入分离系统进行分离；分离后的粉尘颗粒物与新的工业废盐原料混合等待净化,分离后的气体进入催化燃烧系统进行催化燃烧；催化燃烧后的气体经加热后返回鼓泡系统继续对工业废盐原料进行鼓泡流化,构成循环。本发明基于高温热处理技术,利用催化燃烧工业处理循环气高效净化工业废盐,不仅能将工业废盐中的TOC降至30mg/kg以下,而且还可以利用TOC催化燃烧放出的热量,在一定程度上降低能源的消耗,保证设备的稳定、高效运行

Distinct structure-activity relationship and reaction mechanism over CuO/ CeO₂ catalysts for NH3 self-sustained combustion

The catalytic combustion of NH3 to produce nitrogen (N-2) and water (H2O) is a promising method to solve high ignition temperature with more NOx production and poor combustion stability in the carbon-free fuel utilization of NH3. This study focuses on distinct structure-activity relationship over CuO/CeO2 series catalysts and reaction mechanism for catalytic NH3 combustion. Cu/Ce-Sphere, Cu/Ce-Rod, and Cu/Ce-Octahedron catalysts were synthesized through an impregnation method by using different CeO2 carriers (nano sphere (S), rod (R) and octahedron (O)). The activity for NH3 combustion followed an order of Cu/Ce-S > Cu/Ce-R > Cu/Ce-O > Ce-S. The better activity of Cu/Ce-S is attributed to the strong interaction between CuO and Ce-S (111 and 220 planes) at the interface of oxide phases. This interaction is indicative of a higher specific surface area (SSA) to promote CuOx dispersion, facilitating the adsorption of ammonia. Additionally, more Cu-O-x-Ce solid solution with oxygen vacancies enhances the formation and mobility of active oxygen species. The Cu/Ce-S showed a low NH3 lean-combustion limits of 7.6 % NH3 to keep self-sustained combustion, and realized a high NH3 conversion (similar to 100 %) and effective N-2 yield (similar to 98.0 %) with low NOx formation over 360 min. The reaction pathways for NH3 combustion over Cu/Ce-S were revealed by the NH3-TPD/TPR-mass spectrometer, isotopic (O-18(2)) transient exchange experiment and in situ infrared transmission spectroscopy (IR). The Mars-van-Krevelen (M-K) mechanism plays a crucial contribution of adsorbed NHx by ammonia dehydrogenation route to react with active lattice oxygen, and to produce N-2 and H2O. Additionally, the subordinate contribution of Langmuir-Hinshelwood (L-H) mechanism refers the reaction of adsorbed NHx species and chemisorbed oxygen or adsorbed HNO through oxidation route. These results demonstrate the viability of environmentally friendly catalytic combustors for ammonia fuel in the future, and also advance the understanding of reaction mechanism for catalytic ammonia combustion

Catalytic ignition of CO over CuCeZr based catalysts: New insights into the support effects and reaction pathways

Self-sustained catalytic combustion is a promising strategy to remove CO from the off-gas produced during steelmaking, where the potential catalysts are bulk copper-cerium-zirconium mixed oxides or those supported on TiO2 or ZSM-5 substrates. In this study, the effects of the catalyst support on the CO catalytic ignition perfor-mance and reaction pathways were investigated by FTIR coupled with a novel in-situ cell, together with the state-of-the-art characterization techniques. The Infrared (IR) transmission cell equipped with a magnetically driven system, could effectively prevent overlaps between active intermediate peaks (Cu+-CO and Cu+(CO)2) and gaseous CO peaks. The Cu+ cations located at the phase interface are the main active sites. The Cu and Ce in-teractions lead to the formation of solid solutions of CuCe0.75Zr0.25O8 (CuCeZr). The monocarbonyls [Cu+-CO1 are the dominant species during CO oxidation, and the vacancies in the solid solutions are occupied by oxygen, accelerating the oxygen cycle. The TiO2 or ZSM-5 supports promote copper dispersion over CuCe0.75Zr0.25O8/ TiO2 (CuCeZr/T) and CuCe0.75Zr0.25O8/ZSM-5 (CuCeZr/Z) catalysts, which can be attributed to their high surface areas (168.2 and 346.3 m2/g, respectively), while the Cu-Ce interactions are less relevant. Hence, CO oxidation mainly occurs at the phase interface between copper oxide and TiO2/ZSM-5. Dicarbonyls [Cu+(CO)21 are the main intermediates for the CuCeZr/T and CuCeZr/Z catalysts, and the Cu2+ species are reduced to form dicar-bonyls that also take part in the oxidation process. Although a well copper dispersion enhances the activity of individual copper sites on the CuCeZr/T and CuCeZr/Z catalysts, considering the redshift of the carbonyl bands and the increase in CO adsorption, the close interactions and high contents of Cu and Ce favor the local accu-mulation of heat and mass transfer over bulk CuCeZr, leading to the ignition of CO at low temperatures

输卵管性不孕与生殖道解脲支原体感染

目的: 探讨因输卵管炎症性闭塞引起的不孕与女性生殖道解脲支原体( UU)感染关系。方法: 用聚合酶链反应方 法检测 39 例因输卵管闭塞性不孕住院手术治疗患者的宫颈管分泌物、患侧输卵管粘膜的 UU DNA ;以同期住院行输卵管结 扎、因附件良性肿瘤而行一侧附件切除的 30 例病人为对照组。结果: 输卵管闭塞组宫颈管 UU DNA 阳性率为 94. 9%, 显著高 于对照组的23. 3%(P <0. 01)。病变输卵管的 UU DNA 阳性率为 82. 1%, 显著高于对照组13. 3%,(P <0. 01)。结论: 输卵管 炎症性闭塞引起不孕与生殖道解脲支原体上行感染有关

Parametric investigation of the effects of variables controlling thermal characteristics during continuous and high-speed cold stamping processes with active cooling structures

Knowledge of the thermal phenomena that occur during stamping is important for improving the design and performance of stamping die thermal structures. A new mathematical full-scale model for energy and carbon flows is established based on operational data from a cold stamping production line in China. Moreover, numerical simulations of the thermal-fluid-solid coupling field for a cooling medium in an asymmetrically heated rectangular channel with high heat flux and strong wall superheating are carried out with a suitable CFD solver. The results are discussed in detail and compared with theoretical calculations, and the deviation of the surface heat transfer coefficient is +/- 11.9 %. Emphasis is placed on parametric effects of variables controlling thermal characteristics on cold stamping with an active cooling structure. The effects of heat flux, and ambient temperature on temperature rise, pressure drops, and heat transfer coefficients are limited less than 7 degrees C, 167 Pa and 45.11 % under specific operating conditions, respectively. While the heat transfer coefficient and pressure drops are increased hundreds of times with inlet velocity. The fluid cooling performance, threshold value, and approaches for heat transfer enhancement are obtained. Finally, the CO2 emissions rates is assessed as approximately 1.8 g per piece associated with stamping operations, as well as major contributors, CO2 reduction potential, and economic impacts. Negative energy consumption can be achieved with active cooling. These results can help to improve production quality in the future application and provide theoretical support for determining the causes of metal sheet tensile cracking accidents

Migration roles of different oxygen species over Cu/CeO 2 for propane and soot combustion

Determining the migration rules of oxygen species in catalytic combustion, especially for catalysts composed of transition metal oxides, is essential yet challenging. This study hydrothermally synthesized nanospherestructured cerium dioxide (CeO 2 ) and its copper -loaded catalysts (Cu/CeO 2 ) to identify the distinct functions of superficial oxygen species (O) and lattice oxygen (O 2- ). The presence of Cu-Ce solid solution at the Cu/CeO 2 interface lowered the apparent activation energy for the catalytic combustion of propane and soot. The catalytic combustion of propane followed the Mars -van Krevelen mechanism, with O 2- serving as the dominant reactive phase while O played a subordinate role. The solid-solid reaction between soot and superficial oxygen of the catalyst was responsible for catalyzed soot combustion. The O species produced by surface defective sites exhibited higher activity than O 2- , which drained easily at the beginning of the reactions. The isotopic oxygen exchange tests revealed the mechanism of metal oxide (CuO/CeO 2 ) interactions for active oxygen species migration, with the results demonstrating the solid solution at the phase interface as portholes for oxygen migration, thus increasing oxygen mobility between the gaseous phase and the surface by lowering the migration activation energy. In situ, infrared results showed that the reaction path of soot catalytic combustion was single, without any intermediate production formation, compared to multiple paths in the propane oxidation process. This study provided an easily implemented and widely applicable method, which deepens our understanding of the characterization of the function and migration of predominant oxygen species in diverse combustion reactions involving oxide -based catalysts. Additionally, this study clarified differences and similarities between the reaction mechanisms of solid-solid and solid-gas catalysis