Current Issue : October-December Volume : 2025 Issue Number : 4 Articles : 5 Articles
The present study aims to investigate a Pd catalyst on a complex multi-oxide medium-entropy support interlayer La2O3-CeO2-ZrO2-Al2O3 and its possible use as catalysts for methane abatement applications. The low-temperature N2-adsorption, XRD, TEM, XPS, TPD, and TPR techniques were used to characterize the catalyst. The palladium deposition on the supports leads to the formation of PdO. After the catalytic tests, the metal-Pd phase was observed. The complete oxidation of methane on Pd/La-Ce-Zr-Al catalyst takes place at temperatures above 250 ◦C, and in the presence of water vapor, the reaction temperature increases to about 70 ◦C. The careful choice of constituent oxides provides a balance between structural stability and flexibility. The alumina and lanthanum oxide ensure the high specific surface area, while the simultaneous presence of zirconia and ceria leads to the formation of a mixed-oxide phase able to interact with palladium ions by incorporating and de-incorporating them at different conditions. The mechanism of Mars–van Kerevelen was considered as the most probable for the reaction of complete methane oxidation. The possibility of the practical application of Pd-modified La-Ce-Zr-Al catalyst is evaluated. The use of a mix of multiple rare and abundant oxides makes the proposed catalyst a cost-effective alternative....
The post-combustion technology of circulating fluidized beds (CFBs) can largely reduce the emission of nitrogen oxides (NOx) in the process of combustion, significantly reducing the removal cost of NOx. To explore the potential of the combined removal of NOx and SO2 emissions under post-combustion technology, experiments were conducted on a 0.1 MWth circulating fluidized bed test platform. This paper focuses on the effect of temperature in CFB with limestone addition on NOx and SO2 emissions under post-combustion technology combined with sorbent injection into the furnace. The low-cost combined removal of NOx and SO2 can be realized by denitrification in the furnace and through secondary desulfurization in the furnace and post-combustion chamber. In the optimized experimental condition, with combustion temperatures at 845 ◦C and sorbent addition in the furnace under post-combustion, the emission of NOx can be reduced to 47.10 mg/Nm3(@6%O2), and meanwhile, the emission of SO2 can be reduced to 92.09 mg/Nm3. Sulfur removal efficiency is higher under lower temperatures in a weakly reducing atmosphere. The reaction of sulfur fixation occurred in the post-combustion chamber and caused the particle size of fly ashes at the tail flue to become bigger and the sulfur content in the fly ash at the tail flue to increase. At 845–905 ◦C, the combustion temperature had a bigger effect on the SO2 emission than the NOx with sorbent addition in the furnace under post-combustion....
Dou-Gong brackets, the distinctive structural element in ancient Chinese architecture, fulfill critical roles in load transfer, span reduction, and decoration, making its preservation vital for safeguarding wooden heritage buildings. This study investigates the combustion performance and residual load-bearing capacity of key Dou-Gong bracket components—Zuo-dou, Zheng-xin-gua-gong, and Qiao—exposed to varying fire conditions. The results reveal that an increasing fire load elevates heating rates and peak temperatures of wood substrates, resulting in a significant degradation of structural integrity. At a fire load of 55 kW, the peak temperatures at the bottom, joint edge, and top of the Dou-Gong brackets reach 755.3 ◦C, 489.9 ◦C, and 620.7 ◦C, respectively, representing increases of 2%, 65%, and 38%, respectively, compared to those observed at a fire load of 20 kW. Moreover, the charring rate of Dou-Gong bracket increases from 0.22–0.26 mm/min at a fire load of 20 kW to 0.50–0.56 mm/min at a fire load of 55 kW, accompanied by an increase in mass loss rate from 28.5% to 36.9%. These findings highlight the significant impact of fire conditions on the fire characteristic and structural integrity of Dou-Gong brackets, providing the first quantitative evidence of their degradation under fire exposure. By addressing this vulnerability, the study contributes to the scientific preservation of ancient wooden architecture under contemporary fire risk scenarios....
The combustion characteristics of the jet ladle baker were simulated and analysed using Fluent software for different burner configurations. Firstly, a coupled mathematical model of combustion, radiation and convective heat transfer in the jet ladle baking process was constructed using the energy equation, standard k-ε turbulence model, DO radiation model and component transfer model. Then numerical simulations were carried out for the effects of the angle of the obturator, the gap between the obturator and the gas pipe, the length of the gas pipe in depth, and the diameter of the combustion chamber in the baking process for the jet ladle baking burner model. The results demonstrated that the optimal combustion condition was achieved when the angle of the obtuse body was 60°, the gap between the obtuse body and the gas pipe was 20 mm, the length of the gas pipe extending into the combustion chamber was 50 mm, and the diameter of the combustion chamber was 300 mm. The simulation and analysis results can provide reference value for the design of jet ladle baker....
To enhance the efficiency of flue gas purification from straw combustion, a combined approach using the ammonia method and electrostatic charged spray was investigated. This study investigated the charging characteristics of atomized droplets and their impact on flue gas purification. The results show that the charge-to-mass ratio of droplets increases and then decreases as charging voltages increase. At a constant voltage, the ratio increases with higher ammonia concentrations and shows a gradual increase with higher spray pressures. For flue gases from three common straw combustion sources, the average dust removal rate at 8 kV was 2.5 to 3 times higher than at 0 kV. Under the 8 kV condition with a 10% ammonia solution, the NO removal rate was approximately 4.7 times, and the NO2 removal rate was 2.8 times compared to water alone. Particulate matter, NO, and NO2 removal rates were 61.2%, 88.6%, and 88.1%, respectively, at a spray pressure of 0.5 MPa, 8 kV charging voltage, and 10% ammonia concentration. This study provides an experimental foundation for developing high-efficiency flue gas purification systems for straw combustion....
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