Current Opinion in Chemical Engineering最新文献

In comparison to alternative water electrolysis technologies, polymer electrolyte membrane water electrolysis (PEMWE) has several advantages, such as high-voltage efficiency, pure gas production, short response time, and the capability to operate under high pressure and current density. A thorough comprehension of the multiphase flow characteristics within the porous transport layer (PTL) and flow channels is vital to enhance the efficiency of PEMWE. This paper presents an overview of current knowledge on multiphase flow in PEMWE and relevant modeling methods, highlighting the significance of regulating the microstructure of PTL and distinguishing the effects of multiphase flow in the flow channel from those in PTL. Moreover, to simulate PEMWE accurately, it is crucial to consider comprehensive physical and electrochemical processes and develop dependable closure models.

To address potential disruptions that arise from internal and external sources, chemical processes need to be designed with the capacity to withstand and recover from disturbances — often referred to as resilience. To integrate resilience capabilities into process design and operations, it is imperative to be cognizant of contributing factors and develop, determine, and incorporate quantitative resilience performance indicators. This paper provides a brief review of recent progress in conceptual frameworks and quantitative metrics for analyzing and designing resilience-aware process systems. Furthermore, key research opportunities in the field of process system resilience, namely the challenges in integrating resilience throughout the life cycle and across the spatiotemporal scales of a process system, are discussed.

Chemical accidents resulting from thermal runaway of chemical reactors can have severe consequences, including catastrophic damages to the public, society, property, and environment. Therefore, it is crucial to develop a methodology that can predict the safety status of reactors and eliminate the potential risk of thermal runaway timely. To this end, various thermal runaway criteria have been established to assess the safety status of reactors over the past decades. This opinion article provides a short review of classic criteria applied to distinguish between runaway and nonrunaway states of reactors. Particularly, the significance of divergence criterion in the field of thermal runaway criteria is emphasized. In addition, to illustrate the general application procedures of the divergence criterion, examples of its utilization in three research domains, including process safety assessment, process parameter optimization, and process monitoring and control, are given. In summary, the remaining challenges and future directions in the development of thermal runaway criteria, especially the divergence criterion, are discussed.

Alternative water sources can be applied to water-stressed agricultural sites to satisfy the increasing water demand. The increased costs associated with the treatment of impaired water, distribution/conveyance/storage, and waste management to meet water quality requirements and regulations are the challenges in developing an alternative water-based irrigation system. This study evaluates the economic feasibility of developing nontraditional water for agriculture and identifies strategies to address the challenges by increasing affordability. In the Southwest United States, reuse of filtered disinfected municipal wastewater offers the most cost-effective option followed by desalinated brackish water, treated produced water, and seawater. High costs, energy demand, concentrate disposal, and soil salinity management are the primary challenges in using alternative water for irrigation. Economic feasibility can be enhanced by implementing autonomous, easy-to-operate, renewable energy-powered, decentralized desalination systems. The affordability of developing alternative water for irrigation will increase with reduced treatment and waste disposal costs, depletion of conventional irrigation water supplies, and droughts.

Recent advances in nonthermal plasma (NTP)-enabled processes have yielded remarkable results and progress in the remediation of Per- and polyfluoroalkyl substances (PFAS), especially in the past three to five years. In comparison to typical chemical oxidation and reduction reactions that are conducted in bulk aqueous solutions with specific reactive oxidative or reductive species, the reported NTP-based PFAS degradations occur mainly at the water–bubble/air interface and increasingly in the bubble interiors. Further, the degradations occur simultaneously in the presence of a multitude of oxidative and reductive species, including radical, ion, photon, and hydrated electron species. These aspects have introduced some interesting science in such PFAS degradations. This opinion highlights such examples by both illuminating their salient features and more importantly proposing perspectives with respect to the observed science.

In order to achieve net-zero emissions until 2050, it is of utmost importance to improve the energy efficiency and thereby reduce the greenhouse gas emissions in the chemical industry. As distillation processes are accounting for the majority of all fluid separations, they are an important target for potential improvements. Although other separation technologies might be a favorable alternative, distillation is not generally an energy-intensive technology and advanced distillation process concepts, exploiting heat pumps, thermal coupling, as well as solvent- and membrane-assisted hybrid processes, may enable significant improvements regarding energy efficiency. The current article summarizes recent developments regarding the synthesis and design of energy-efficient distillation processes and points out future needs and directions for developments to foster the systematic evaluation and application of these advanced distillation process concepts.

The interplay of water, energy, and food resources, which are essential for human sustenance, symbolizes a complex challenge involving social, engineering, and environmental aspects. The water–energy–food (WEF) nexus, surpassing traditional process systems engineering (PSE), underscores the interconnectedness of resource decisions. Efficient WEF nexus management demands a comprehensive approach encompassing environmental, social, economic, and technical dimensions. PSE tools are vital in shaping this nexus, facilitating a deeper resource interaction and promoting sustainability. This opinion article introduces a novel classification for WEF-specific PSE, advocating for a holistic approach that acknowledges dynamic resource interdependencies. Innovative strategies addressing WEF challenges are proposed, leveraging advanced computational solutions that enhance the nexus models' realism. This trajectory promises insights into nexus intricacies and reflects a shared commitment to harmonize resource coexistence. As we explore the interrelation between water, energy, and food, a path emerges toward the alignment of human and environmental needs, offering a sustainable world trajectory.

The presence of iron in the electrolyte has a significant impact on the performance of the electrodes in alkaline water electrolysis. For nickel-based anodes, the presence of iron is needed to achieve and maintain low overpotentials in the oxygen evolution reaction (OER). In contrast, in hydrogen evolution, the presence of iron can lead to deactivation of noble metal-based cathodes, which are more active than non-noble metal cathodes. Since the catholyte and anolyte can mix through the porous separator, stack developers need to decide on the optimal iron content in their system. It seems most promising to focus further development on the ‘iron-rich’ system, also considering the costs of construction materials and water purification.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are extensively distributed, highly persistent, and hazardous compounds in water resources threating human health and ecosystems, therefore requiring effective controlling and management systems. Machine learning (ML)-based procedures are novel approaches through which the PFAS-controlling systems can be improved cost-effectively and rapidly from different aspects. The few accomplished ML-based studies in PFAS-controlling systems showed considerable performance, with > 80% prediction strength in outputs, for example, treatment performance, identification of the susceptible groundwater resources, and PFAS defluorination energy in > 70% of the studies. Despite such a great performance, there is no systematic study of various aspects of PFAS-controlling systems, for example, modeling and analysis of PFAS degradation and distribution mechanisms, optimization, alarm management, troubleshooting, and appropriate operation and maintenance of these systems. Therefore, this study reviews key aspects and parameters that can take advantage of ML procedures in achieving cost-effective PFAS control in water resources.

Increasing carbon dioxide emissions and the resulting global warming are a critical environmental concern. Ionic liquids (ILs) have recently gained attention as promising absorbents for carbon capture due to their favorable chemical and physical properties. Consequently, there is a need to develop process modeling and mathematical optimization techniques for the design and operation of IL-based carbon capture processes to identify optimal design and operation. This review presents recent advances in modeling and optimization of carbon capture plants using ILs. We focus on flowsheet simulation, nonlinear dynamics, variations in plant load and energy prices, and multiscale design.