Chemical Engineering and Processing - Process Intensification最新文献

Nowadays, the food industry is undergoing a significant transformation in traditional processing techniques. Several process intensification principles, such as reducing energy and water consumption, waste handling, miniaturizing process plants, and integrating process and product innovation, can be found in implementing emergent technologies. The main contributions of the research group led by the author on the application of UV light-based radiation processes, enhanced extraction of bioactive compounds, combined drying technologies, and trends in designing functionalized materials are discussed. Besides, gaps in the different research topics are highlighted, aiming to give a perspective of opportunity areas for future research.

Process intensification, especially the clean utilization processing of coal tar, is significant for the development of coal-based fine chemicals. However, coal tar is traditionally hydrogenated by full-fraction hydrotreating to prepare gasoline and diesel oil, which leads to underutilization of key components and lack of process intensification innovations. Therefore, the combination of coal tar with sustainable solar energy along with the emerging enhanced separation and conversion of polycyclic aromatic hydrocarbons is expected to open up a new way for the clean utilization of coal tar in chemical production. For the aromatic-rich coal tar distillation section, the phenolic compounds are separated first, and the aromatic hydrocarbons are then directed to prepare solar thermal fuels, which not only reduces the hydrogen consumption of the whole process, but also has a high yield of the target product, which greatly improves the added value of the product. Recently proposed coal-based solar thermal fuels can provide storage energy densities up to 0.3 MJ kg⁻¹ and on-demand controllable heat release through reversible transformation of the molecular structures, showing great potential for applications in smart wearable and circulating heating. The process of coal-based solar thermal fuels’ production involves component analysis, separation and chemical synthesis, and its process intensification innovations would help to improve the clean and efficient utilization of coal tar.

The spinning disc reactor (SDR) is an intensification reactor which shows outstanding mass and heat transfer characteristics. It has been applied to various applications. This perspective presents an overview of SDR technology development from 1967 to 2024 and provides insights into SDR design and key variables influencing mass transfer and micro-mixing efficiency of SDR. It focuses on the main obstacles to this technology's industrial applications as well as the necessary research to overcome them. In addition, the possible areas of the synergy between the SDR and other technologies to advance chemical processing are highlighted.

This paper presents the results of an investigation into the effect of silica nanoparticles on two-phase flow regimes in a Y-shaped microchannel. The following fluids were subjected to investigation: oil, water, and a water-based suspension containing SiO2 nanoparticles at a weight concentration of 1 ≤ φ ≤ 10 %. A systematic investigation of the flow regimes revealed the following: slug, parallel, and droplet regimes. The ranges of existence of the obtained flow regimes were determined and flow regime maps were constructed as a function of fluid flow rates and dimensionless numbers. The results of the study demonstrated that the slug length and frequency of slug formation are influenced by varying silica concentrations. Furthermore, the correlation between slug length and nanoparticle concentration remains consistent as the suspension flow rate increases. The dependence of the ratio of oil layer width to channel width for suspensions with varying nanoparticle concentrations was quantified. A mathematical simulation of two-phase flow of immiscible fluids was conducted. The results of the numerical simulation demonstrated the existence of the flow regimes that had been previously identified through experimentation. The aforementioned methodology may therefore be employed for the investigation of the two-phase immiscible flow of oil and nanosuspension.

Hybrid advanced oxidation processes (AOPs) are gaining interest in degradation of variety of recalcitrant compounds for water and wastewater treatment, due to possible synergistic effects. The present study systematically evaluated the degradation of tetracycline (TC) with a sonophotocatalytic process combining acoustic cavitation (sonocavitation) and photocatalysis based on N-doped TiO₂ catalyst. The TC degradation rate constant was 2.4 × 10⁻² min⁻¹, i.e., much higher than individual sonocatalytic (0.5 × 10⁻² min⁻¹) and photocatalysis (0.6 × 10⁻² min⁻¹) processes at the optimized conditions. The synergy index was 2.14, which reveals a significant improvement in the process performance. Maximum TC degradations of 55.5 ± 1.8 % for photocatalysis, 66.4 ± 1.8 % for sonocatalysis, and 79.5 ± 0.3 % for sonophotocatalysis were observed for 10 mg L⁻¹ initial TC concentration after 90 min of treatment. The photocatalytic experiments were extended further to 210 min to achieve a maximum degradation of 78.9 ± 0.2 % at the optimized condition. Scavenging experiments confirmed that hydroxyl radicals (^•OH), electron holes (h⁺), and superoxide radical anions (O₂^−•) played a significant role in the degradation of TC. Further, the degradation intermediates for each process were identified and degradation pathways were proposed. Empirical kinetic models based on operational parameters were also developed and validated.

Aerothermal performances of four two-pass channels enhanced by tilted 90° or 60° grater-baffles with one- or two-rows of perforation are studied. Aerothermal impacts of baffle attack angle and perforation row-number on Nusselt number (Nu) distribution, friction factor (f), and aerothermal performance index (API) are cross examined. Cold streams from duct core are confluent in oval dimples to eject through inclined grater-baffle as impinging jets that diminish boundary layers at stagnation spots and augment core-to-wall mixings, leading to significant heat transfer enhancements (HTE). Heat transfer data reveals that the HTE impact increases and decreases with perforation-row number and Reynolds number (Re) respectively. With the sectional vortical flows tripped by the 60° grater-baffles, both Nu and f are raised from those with the 90° baffles. The Nusselt numbers and friction factors for the two-pass channel enhanced by the inclined 60° baffles with two perforation rows are elevated to 4.64–4.95and 33.67–34.16 times Dittus-Boelter correlation and Blasius equation levels, giving rise to the API in the range of 1.67 and 1.43 at Re between 5000 and 15,000. Empirical correlations of regional average Nu and channel average f for the four two-pass baffled channels are devised to assist engineering applications.

The manufacturing industry, in general, is a major consumer of heat and power. Producing them in a combined manner from conventional fuels is called cogeneration and is widely practiced in the industry. This paper attempts to provide a comprehensive review of cogeneration as used in a variety of industries. Various techniques and arrangements of cogeneration cycles (theoretical and active) and their implementation challenges are discussed with examples of studies from various countries. Our observations and recommendations extracted from these studies for implementing cogeneration in these industries are also discussed.

Thermal management in some small chemical reactors is essential to achieve a final high-quality product and heat sinks can play a remarkable role in dissipating heat from such systems. In this regard, this study attends to evaluate the conjugate heat transfer problem in a heat sink equipped by twisted elliptical tubes (TETs). The effects of significant parameters such as Reynolds number (Re = 250, 350, 500, 700 and 950) and twist ratio (TR = 2.5, 5 and 10) on hydrothermal and thermodynamics performance of the novel heat sink are investigated. The swirling flow is the main reason of fluid particles migration from hot surface to cold one and vice versa, leading a better heat transfer occurs at the expense of not significant pressure loss augmentation. The results revealed that the TETs are responsible of more wall temperature uniformity and avoids generating hot spots. Compared with plain elliptical tubes, the presence of TETs inside heat sink improves the heat transfer rate and enlarges the pressure drop by 1.08–2.03 times and by 1.02–1.92 times, respectively. In addition, the TETs decrease the entropy generation rate inside heat sink and the best value of second law efficiency is about 35 %, detected at TR = 2.5 and Re = 250.

Traditional stirring methods in the wet metallurgy leaching process suffer from low efficiency, high consumption, and low output, leading to increased production costs and energy consumption. Therefore, this study evaluates reactor performance using deep learning and introduces variable-speed stirring to enhance laminar mixing and reduce stirring reactor power consumption. An S-Type acceleration and deceleration control algorithm is constructed to ensure that stepper motors do not experience step loss, stalling, or overshoot when the frequency changes abruptly. A deep learning tracking model based on dual cameras is established to dynamically track tracer particles inside the stirring reactor, and a Euclidean distance evaluation method is proposed to characterize and evaluate the mixing performance of the stirring reactor. Experimental results demonstrate that the use of complex function variable-speed stirring and shortening the variable-speed cycle both contribute to improving mixing efficiency. Under a variable-speed cycle of 5 s, chaotic speed increases mixing efficiency by 53.1 % compared to constant speed. This study provides a theoretical basis for optimizing the wet metallurgy leaching process.

This paper demonstrates a numerical simulation study to understand particle deposition phenomena in wavy pipe configurations comprehensively. The research investigates the intricate dynamics of particle deposition within wavy pipes by utilizing the RNG k-ε turbulence model with enhanced wall treatment for fluid flow simulation and employing a Lagrangian particle tracking model. The finite volume approach is adopted to solve the mathematical model of the current problem. The rate of aerosol particle deposition within a wavy pipe under turbulent flow conditions is systematically explored by varying the size of particles (1 ≤ d_p (μm) ≤ 30), Reynolds numbers (5000 ≤ Re ≤ 10,000), and other parameters like wave frequency (3 ≤ f ≤ 7), wave amplitude (5 ≤ a (mm) ≤ 15), and diameter of the pipe (10 ≤ D (mm) ≤ 30). The findings reveal significant correlations between these parameters and deposition efficiency, shedding light on the complex interplay between geometric factors and flow characteristics within the wavy pipe configurations. Notably, larger pipe diameters and higher wave amplitudes are found to enhance deposition rates, while the optimal wave frequencies exist at intermediate values. Additionally, alterations in flow velocity exhibit an inverse relationship with deposition efficiency.