Advances in Science and Technology Vol. 166

Abstract: Manganese dioxide-modified montmorillonite (MnO₂/MMT), a one-step hydrothermal procedure was utilized for fabricating the composites. The structure, morphology and the particulars of the components were explained by XRD, SEM and BET, which proved that MnO₂/MMT composites were successfully synthesized. Conclusions of the experiment show that the adsorption efficiency of MnO₂/MMT reached 99.63% after 5 hours of adsorption for Cr(VI) solution, which was considerably greater than that of the unmodified montmorillonite under the same conditions. The above study highlights how MnO₂/MMT can be used in the wastewater treatment.

Abstract: Clarifying the distribution of cadmium (Cd) and lead (Pb) in the soil of Hainan's Se-rich areas will not only provide a basis for the healthy and sustainable development of Hainan's Se-rich industry, but also provide ideas for Hainan's agricultural and food safety research. Using a method that combines field investigation and indoor analysis, with the help of geostatistics and spatial analysis technology, the concentration of Pb and Cd in the soil and rice in the area were studied. The Cd in the cultivated soil layer of the arableland in the area is lower than the first-level standard of our country's soil environmental quality standards, and the soil Pb content is slightly higher than the first-level standard. The overall ecological risk is low. Pb and Cd in polished rice are 0.14 and 0.11 mg/kg respectively. The concentrations distribution of lead and cadmium in rice is: straw > polished rice. Heavy metals are more likely to accumulate in non-edible parts such as straw.

Abstract: Hainan soil pH continues to decrease, and the reduced soil selenium availability of stagnic anthrosols caused by soil acidification influence the selenium absorption in selenium-rich areas. Taking stagnic anthrosols in selenium-rich areas as the object, the soil total selenium concentration and sequential fractionations of surface layer were analyzed, which are Exchangeable (EX), Carbonate-bound (AC), Fe & Mn oxided-bound (OX), Organic-bound (OC) and Residual (RES). The results show that selenium in soil is unevenly distributed among various fractionations, with the RES and OC accounting for the highest proportion. The sum of the selenium content of these two forms is 89.84%. The AC is easily absorbed and utilized by crops. The selenium content in EX and AC are only 1.64% and 2.17%. Soil pH has the most significant impact on the content of EX. Soil acidification will significantly reduce the proportion of this part of selenium, resulting in a decrease in the bioavailability of soil selenium. Especially when the soil pH is higher than 5.5, the proportion of EX in the soil increases with the the pH dropped significantly.

Abstract: Gas-liquid two phase flow of blast furnace taphole stream into the main trough is studied through computational fluid dynamics (CFD) method. Tapping process of blast furnace with different taphole angles is simulated by volume of fluid model of CFD. The velocity and region of taphole stream into flow within the main trough is analyzed. It is concluded that the tophole case with bigger angle is conducive to slag-metal separation in the main trough.

Abstract: Gravity dust-catcher is one of wildly used dedusting mechanical equipment in industry field, which separates dust from gas flow through gravitational precipitation. The gravity dust-catcher for blast furnace gas in one steel plant is researched with computer numerical simulation in this work. Based on the flow pattern analysis and particles separation efficiency computation, an optimization scheme is proposed for the blast furnace overhaul. The dust collection efficiency is improved evidently, which has been validated in the new campaign life of the blast furnace.

Abstract: In automated melt-casted Aluminium production process, lots of carbon dioxides are emitted. How to accurately calculate those carbon emissions is a challenging problem. In this paper, we mainly introduce a carbon emission calculation method based on global power consumption for the automated melt-casted Aluminium production process. Firstly, we analyse the carbon life cycle of the melt-casted Aluminium products and the carbon emission calculation boundary. Then, the power consumption based-calculation method of the carbon emissions of different stages of the melt-casted Aluminium product are explained in detail and finally, the total emissions are offered. The simulation results indicate that the global power consumption based-carbon emission calculation method works well in the automated melt-casted Aluminium product process.

Abstract: As China's mechanical and electrical equipment manufacturing capacity improves and the international political environment changes, more and more mechanical and electrical equipment manufacturers are actively deploying overseas exports of equipment or investing overseas to build factories. The larger market size offers enterprises broader development space and a higher profit level. However, at the same time, due to factors such as incompatibility of domestic and foreign standards and differences in usage habits, various problems have emerged during the process of being put into use overseas. Based on visits to several equipment enterprises and focusing on the equipment control system, this paper summarizes various issues related to equipment export, including environmental protection, certification, and services. It provides suggestions for reference in terms of close cooperation from manufacturers to end-users, refinement of domestic and foreign industry certification systems, competitiveness of overseas sales, logistics policies, and mutual support among industries. It is hoped that this can be helpful for the equipment development and export business of equipment manufacturing enterprises.

Abstract: The reform of the electricity market has driven the optimization demand for distributed energy, which involves energy conversion efficiency in mechanical mechanics and intelligent control strategies in automation technology to ensure that virtual power plants can achieve maximum economic benefits. This chapter first analyzes the technical characteristics of demand response; Secondly, with the goal of maximizing the operating income of virtual power plant, a bidding optimization model considering the participation of demand response technology in virtual power plant operation is established, and the solution method is designed. Finally, the empirical analysis of the demonstration project shows that when the virtual power plant participates in the operation of internal and external markets, each energy conversion equipment has a certain impact on it. The benefits brought by the comprehensive consideration of demand response technology and the independent consideration of demand response technology are different, respectively, 197,322 yuan and 102,388 yuan. It is proved that virtual power plant can obtain higher benefits than traditional demand response.

Abstract: Modern pipeline steel has high toughness and ductility, which can effectively prevent long-distance crack propagation. The full-scale blasting test is the most effective method to verify and evaluate the crack propagation and arrest behavior in high-grade pipeline steel pipes. This article investigates the crack propagation and crack arrest behavior of X90 grade natural gas pipeline steel pipes through full-scale blasting tests. The test results show that once the X90 grade natural gas pipeline steel pipe cracks and propagation under a pressure of 12MPa, as long as the Charpy impact toughness CVN of the steel pipe is greater than 286J, it can ensure effective crack arrest of the pipeline, providing technical support for the application of X90 high-grade pipeline steel pipe in high-pressure transmission pipelines.