The reutilization of coke oven gas (COG), a byproduct of steel manufacturing, is increasingly emphasized as a strategy to improve energy efficiency and reduce emissions. However, raw COG contains hydrogen sulfide (H2S) and ammonia (NH3) impurities, which can lead to equipment corrosion, catalyst deactivation, and environmental pollution, thereby limiting its direct reuse. Limited research has quantitatively compared the performance of conventional amine-based purification systems with emerging integrated-column configurations for simultaneous removal of H2S and NH3. In this study, two COG purification configurations were modeled using Aspen Plus and systematically compared from 2ES (Energy, Economic, and Safety) perspectives. Case 1 represents a conventional absorption-regeneration process employing a methyldiethanolamine (MDEA)-based amine solvent, whereas Case 2 integrates the H2S and NH3 scrubbers into a single column. Both cases were modeled under identical inlet conditions to achieve a 95% H2S removal efficiency. The comparative analysis reveals a clear trade-off between energy efficiency and safety. While the economic performance of the two cases was nearly identical, with only similar to 1% difference in gas processing cost (GPC), Case 2 exhibited an energy-saving potential of about 65% compared to Case 1. However, under a large accidental release scenario, Case 2 indicated a leakage rate about 3.6 times higher, leading to a hazard radius approximately 1.7 times larger than that of Case 1. These findings highlight that the MDEA-based absorption process is more favorable from a safety perspective, whereas the integrated NH3/H2S column process offers a substantial advantage in energy efficiency.
The efficient, economical, and sustainable generation and distribution of power represents a major global challenge with significant technological and social implications. A common approach to solving this complex problem involves formulating it within a mathematical optimization framework, which typically incorporates both discrete and continuous decision variables. Due to the inherent complexity of these optimization problems, conventional practice often necessitates the use of a problem decomposition scheme to enable solution derivation. While this decoupling procedure facilitates the computation of solutions, the removal of intrinsic problem interactions inherently leads to a solution that is, at best, suboptimal. To address this limitation and seek optimal solutions, this work investigates the application of the Quantum Computing paradigm for solving a realistic, albeit reduced, version of the Mexican energy system. In particular, we address the QUBO-QAOA solution of a deterministic UC/ED instance under fixed hourly demand and deterministic generator parameters. The primary objectives of this work are to identify suitable optimization formulations amenable to quantum algorithms, determine the potential advantages and disadvantages of using Quantum Computing for this specific domain and examine the scalability and characteristic requirements imposed by power generation and distribution systems. As the availability of quantum processors and robust, noise-tolerant quantum systems increases, quantum computing is anticipated to become capable of providing optimal solutions to some of the most challenging scientific and technological problems across diverse fields, including materials design, computational fluid dynamics, and logistics.
To clarify the oxidation kinetics and controlling mechanism of iron vanadium spinel (FeV2O4) in air at elevated temperatures, high purity FeV2O4 samples were subjected to isothermal thermogravimetric oxidation at 450-700 degrees C. The thermogravimetric data were used to establish the conversion versus time and reaction rate versus conversion relationships, on the basis of which the oxidation process was divided into two kinetic stages. Solidstate kinetic models for each stage were then fitted and evaluated using both the linear integral method and the nonlinear least squares method, and their suitability was further examined by residual analysis. The results indicate that the first stage is best described by the A3 model, whereas the second stage is more consistent with the D3 model. This result suggests that the rate-controlling step gradually changes from an initial nucleation and growth process to a diffusion controlled process in the product layer. Iso-conversional analysis further shows that the apparent activation energy increases from 50 to 174 kJ & sdot;mol- 1 as conversion increases, indicating that the reaction becomes progressively governed by steps associated with higher energy barriers. This trend is consistent with the change in controlling mechanism identified for the two stages. In addition, XRD and XPS analyses reveal the coupled evolution of phase reconstruction and valence states during FeV2O4 oxidation. These findings provide useful guidance for understanding oxidation behavior in vanadium-bearing systems and for optimizing hightemperature oxidative vanadium extraction processes.
The escalation in annual oilfield production and water content in produced fluids has drawn increased attention towards downhole oil-water separation technology. Among various solutions, hydrocyclone-based downhole separation devices are being extensively studied. This work proposes an axial inlet hydrocyclone incorporating guide spiral vanes for swirl generation to overcome limitations of conventional hydrocyclones, such as restricted operating windows and inadequate separation performance. Laboratory experiments were first conducted to evaluate the separation performance, demonstrating that the modified hydrocyclone significantly expands the operating window. With split ratios ranging from 20% to 50%, it achieves separation efficiency exceeding 99% and maintains underflow oil concentration below 150 mg/L. Under high water-cut conditions, this value can be further reduced to below 60 mg/L. Furthermore, Computational Fluid Dynamics (CFD) simulations were performed to investigate the effects of spiral vane outlet angle and guide section length on internal flow field characteristics. Numerical results indicate that an optimal conversion efficiency between inlet momentum and separation force is achieved at a vane outlet angle of 27.75 degrees. A guide section length of 9 mm provides an optimal balance between turbulence suppression, droplet size control, and energy dissipation, thereby stabilizing the flow field and enhancing reverse oil discharge efficiency. These findings, integrating experimental validation with mechanistic analysis, suggest significant potential for practical application of this separator in downhole oilwater separation.
Turbulent emulsification devices are used in many applications of chemical engineering. There is large need to predict the drop sizes resulting from such devices, for example in the context of designing new devices, modifying current design, or adapting designs to new products. The Kolmogorov-Hinze framework is the most used approach, much due to its simplicity and flexibility. However, there is not only one Kolmogorov-Hinze model but several, differing in modelling assumptions and on model complexity. This contribution provides a review focusing on how reliable the framework is in its current form for making predictions on new conditions, on when the different extended forms of the framework are needed to obtain a high predictive power, and on what are the limitations or missing pieces of understanding in contemporary literature. The perspective is that of a researcher or engineer interested in using Kolmogorov-Hinze theory to make predictions in an applied setting.
