Articles
Environmental Progress and Sustainable Energy (19447450)
The substantial demand for hot and cold utilities in the operation of close-boiling distillation systems has prompted the development of various process configurations, including vapor recompression and distillation without hot utilities (DWHU). However, despite their advanced technical capabilities, DWHU configurations have yet to undergo comprehensive environmental assessments or optimizations, nor have they been compared to alternative separation systems to identify the most sustainable process options. This study addresses this gap by conducting process simulations, environmental evaluations, and optimizations utilizing genetic algorithms (GA) to compare various conceptual designs of distillation processes—both conventional and intensified—specifically for a sample propylene/propane separation system. Notably, the results indicate that with the appropriate configuration of DWHU, it is feasible to achieve substantial reductions in global warming, acidification, marine eutrophication, and terrestrial eutrophication potentials. Also, global warming, fossil depletion, and eutrophication potentials were evaluated and compared for different process configurations. © 2025 American Institute of Chemical Engineers.
Thermal Science and Engineering Progress (24519049)61
In this study, an industrial scale linear alkylbenzene production plant was simulated and validated against the operational data. Subsequently, exergy analysis was carried out to assess the individual equipment irreversibility. The results showed that the distillation towers accounted for the highest exergy loss within the process. This can be attributed to the highest rates of hot and cold utilities consumption within the columns, resulting in significant exergy loss. The pathfinder optimization algorithm based on the objective functions minimizing exergy loss and energy consumption in the process was used for finding the optimal operational parameters of the process. As a result, a remarkable 18% and 24% economic savings in terms of the total annualized costs of the process were obtained, respectively. Also, an environmental evaluation was carried out on individual equipment and the whole process and it was found that the hot utility requirements of the process are responsible for more than 90% of the environmental impacts such as acidification potential, global warming potential and abiotic depletion potential. Through the optimizations, a 19% reduction in global warming impact of the process was achieved.
Chemical Engineering Science (00092509)295
Various configurations of vapor recompression heat pumps were previously proposed for enhancing its thermodynamic and/or economic performance. The outcomes of prior publications were documented using fundamentally distinct separation systems, making it challenging for process engineers to decisively determine the optimal processing options for a particular separation task. This difficulty arises from the variations in thermophysical properties exhibited by the materials involved. Despite limited research on bottom flashing heat pumps, they offer advantages over vapor recompression such as lower operating pressure and temperature in process sections. This can result in cost savings and safer operation. In this paper, novel configurations of bottom flashing are proposed, based on the ideas and schemes, previously proposed for vapor recompression. The novel processing systems were proposed and applied on propylene/propane and i-butane/n-butane separation processes as samples of close-boiling distillation systems. This study showed that the bottom flashing systems showed greater economic performances compared to vapor recompression for i-butane/n-butane separation. total annual costs savings of 19.0% was obtained, using the novel configuration of heat recuperated bottom flashing configuration on isobutane/n-butane separation. Also, annualized costs of the systems based on bottom flashing were 10.9%, 4.2% and 7.3% lower than their equivalent vapor recompression processes. © 2024 Elsevier Ltd
Chemical Engineering Journal (13858947)405
The side reactions play an evident role in the selectivity of propylene in methanol to propylene (MTP) process. Recycling by-products such as C4 and C5 hydrocarbon cuts is an effective way to utilize these hydrocarbons and to improve the propylene selectivity. So, the aim of this study was to present a kinetic model for the MTP process over the H-ZSM-5 (Si/Al = 200) catalyst in the presence of co-reaction of methanol and C4-C5 olefin mixture based on the Langmuir-Hinshelwood theory. This model was established on a comprehensive mechanism including methanol conversion, methylation, cracking, hydrogenation, dehydrogenation, and oligomerization reactions. The Response Surface Methodology based on Central Composite Design was applied to evaluate the impact of C4= (5–16 wt%) and C5= (2–9 wt%) mass fraction, WHSV (1.93–7.73 h−1), and temperature (455–485 °C) on the product distribution. It was found that the co-feeding of C4-C5 olefin mixture with methanol can enhance the propylene selectivity up to 73% by controlling the operating conditions. The excellent agreement between the model prediction and experimental data shows that the proposed kinetic model accurately describes the product distribution, and is applicable to this process. © 2020 Elsevier B.V.
Applied Physics A: Materials Science and Processing (14320630)127(10)
Metronidazole (MTZ) is an antibacterial drug, which is frequently detected in wastewater, resulting in pathogen-resistance and mutagenicity. Therefore, MTZ removal is a serious challenge. In this research work, the visible-light-driven Z-scheme CuWO4/Bi2S3 heterojunction with optimized weight percentage (7%wt) was evaluated for MTZ degradation under LED radiation in batch and continues reactor. The effect of operational factors such as MTZ concentration (10–30 ppm), catalyst dose (0.4–1 mg/L), pH (3–9) and illumination time (90–150 min) on MTZ degradation efficiency was investigated through response surface methodology (RSM). The optimum values of the operating parameters were found to be as: irradiation time = 150 min, pH = 3, MTZ concentration of 10 ppm and catalyst dose = 0.7 g/L. The utmost degradation efficiencies were obtained 79% and 84%, respectively, in batch and continues flow mode at the optimum conditions. Thereafter, the effect of immobilization of the binary composite on FTO was studied at the obtained optimum conditions. The effect of temperature and light intensity on photocatalytic performance was also investigated, and the optimal values were found to be 25 °C and 400 W/m2, respectively. The mineralization of MTZ was investigated through TOC removal rates with the maximum value of 61.32%. The gas chromatography-mass spectrometry analysis was used to detect the photodegradation intermediates. The kinetic study of MTZ degradation by the binary composite followed the pseudo-first order by the reaction rate of 2 times greater than pristine Bi2S3. The main active species were found to be hydroxyl radical and superoxide by the trapping test method. The binary heterojunction demonstrated high durability and stability after five cycles. This work recommends a promising heterojunction for MTZ photodegradation. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.
