Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) - Volume 17, Issue 4, 2024

The most important task in the development of modern chemical engineering is to improve the quality of metal products and parts made from them, increase their efficiency, reliability, and fatigue life, bring these indicators to the level of world standards, and ensure the competitiveness of domestic products in the foreign market. The structural safety of chemical engineering equipment is largely determined by the operational reliability of its component elements. The most common and progressive way of their manufacture is cold pressing methods, the quality and reliability of which are largely defined by the condition of the gauged bars' surface. At the same time, the performance characteristics of machinery parts and mechanisms are determined mainly by the properties of the surface layers of metal, since all destruction processes, especially during cyclic loading, usually start from the surface and depend on its structure and physical and chemical status. The role of the type of metal surface imperfection increases greatly with corrosion fatigue, which is determined by the formation of protective barrier films. In the absence of stress, these films reduce the rate of corrosion, and during cyclic loading, they are continuously destroyed. In addition, a stress concentration appears that is caused by surface damage, leading to the formation of corrosive cavities on it. In this paper, based on theoretical research, a physical parameter is proposed that controls the corrosion fatigue life of strain-hardened structural materials of chemical engineering, serving as an indicator of the degree of strain hardening under static tension. An analysis of experimental data has confirmed that the technological plastic processing of structural materials, leading to a decrease in the value of this indicator, causes an increase in their resistance to corrosion-fatigue failure.

The purpose of this work was to identify a physical parameter that controls the corrosion fatigue life of technologically processed structural materials of chemical engineering.

The experimental test procedure included mechanical tests under static and cyclic loading. Structural materials widely used in chemical engineering, prestrained at different degrees, were selected for the study. Static tension tests of standard samples were carried out on ZD 10/90 and UME-10TM machines with a strain rate of 2 × 10^-3 sec^–1. The samples were loaded at a frequency of 50 Hz using the MIP-8 machine. A widely spread 3% aqueous solution of sea salt was used for testing in a corrosive environment.

It has been established that a physical parameter that controls the corrosion fatigue life of materials is the exponent in the equation of the strain hardening curve under static tension. It has been shown that the process of plastic treatment of material, leading to a decrease in its size, causes an increase in its resistance to corrosion-fatigue failure.

It has been shown that in order to assess the feasibility of a particular process treatment in order to increase the resistance to corrosion fatigue of structural materials, it is necessary to trace its impact on the value of the strain hardening index under static tension.

Dye-containing wastewater causes irreparable damage to the ecological water system. Although adsorbents are widely used for treating wastewater containing dyes, the comparative investigation on these materials is still insufficient for their wide applications in the industries.

With the aim of comparing efficient and fast adsorbent materials for cationic dyes, we analyzed and evaluated the adsorbents of the MCM-41 molecular sieve and activated carbons.

The adsorption performance was studied on the common colored organics, such as cationic dyes of rhodamine B (RhB) and methylene blue (MB) dyes. The present work examined the impact of experimental variables, including initial dye concentration, adsorption time, and pH, on the adsorption process and performance, as well as the adsorption kinetics of the diverse adsorbents towards two cationic dyes.

MCM-41 molecular sieves showed relatively high adsorption capacity for RhB and the activated carbon AC-2 made their adsorption capacity for MB much higher than that of MCM-41 molecular sieves. A comprehensive analysis was conducted using pseudo-first-order and pseudo-second-order to decipher the mechanism of dye adsorption. The heterogeneous adsorption mechanism could explain the dye adsorption behavior of MCM-41 molecular sieve and activated carbons.

The results demonstrated the influence of the pore structure and surface properties of the adsorbents on the adsorption capacity of dye molecules in an aqueous solution. For the initial concentration of cationic dye solutions of 20 mg/L, the MCM-41 molecular sieve had a MB adsorption capacity of 130.8 mg/g under alkaline conditions at pH=10, while the activated carbon adsorbents showed a stable MB adsorption capacity of 266.6 mg/g under different pH conditions, proving their applicability in treating wastewater containing dyes under different acid/base environments.

Subsequent commutation failures (SCFs) in high-voltage direct current (HVDC) systems pose a serious threat to the safe operation of hybrid AC/DC grids. Electrochemical energy storage, which is widely distributed at the sending end of ultra-high voltage direct current (UHVDC) transmission systems, has the potential to mitigate SCFs. To fully harness the SCF-mitigating capabilities of energy storage, this article first establishes a CIGRE-HVDC standard test model incorporating electrochemical energy storage at the sending end.

Based on this model, the factors influencing DC commutation failures are investigated. Furthermore, the impact of rectifier-side electrochemical energy storage (EES) on inverter-side commutation failures is explored from three aspects: energy storage capacity, output magnitude, and fault conditions. It is found that rectifier-side EES absorbing power can effectively suppress inverter-side commutation failures. Finally, based on this finding, a transient active power control strategy for energy storage is designed to inhibit consecutive commutation failures and is studied on the CIGRE-HVDC standard test system. It is concluded that the optimal capacity for suppressing SCFs is between 20% and 30% of the DC capacity, and the best absorption power output is achieved with a per-unit value of 1.

Simulation results confirm the correctness of the proposed energy storage transient active power control strategy and its effectiveness in suppressing SCF under different fault moments, fault severities, and fault types.

This strategy can limit the number of SCFs to three or fewer in the majority of operating conditions, facilitating rapid system recovery after faults.

In this study, we conducted a bibliometric study about steel casting between the year 2000-2023. We carried out a bibliometric analysis of sand casting, investment casting, die casting, and squeeze casting in which optimization and simulation models are available and have been thoroughly developed to enhance the quality of the casting product, according to the keyword co-occurrence network and word cloud generated by the bibliometric analysis and text mining of the publications.

By delving further into the optimisation and simulation models, this study finds multiple casting procedures with various process parameters that have a major effect on the process results. Defects of the mechanical kind are the most prevalent, and factors taken into consideration are emissions, yield, dimensional tolerances, and qualities.

The necessity for data-driven modelling in new casting environments has been identified in this study, which will allow for a dynamic casting process and fine-tuning and aid in attaining desirable results in today's competitive markets. In order to illustrate the future prospects of this sector, this research focuses on potential technical interventions in steel casting processes that could enhance the efficiency of the process and the quality of the products produced by steel casting.

This study examines the body of literature on various researchers' contributions to the production of excellent casting components and performs a bibliometric examination of the publications. However, the literature study examines research publications from high-quality essential sources to determine the essential criteria influencing steel casting quality.