Evaluating the Exergetic Performance of the Amine Treatment Unit in a Latin-American Refinery

Computer-Aided Modeling, Simulation, and Exergy Analysis of Large-Scale Production of Magnetite (Fe3O4) Nanoparticles via Coprecipitation

Magnetite nanoparticles present attractive properties including high magnetization, low toxicity, adsorption capacity, and simple preparation, making them efficient in water purification processes, soil remediation, and biomedical applications. In this sense, there is growing interest in the production of magnetite nanoparticles; therefore, evaluating the performance of this process on a large scale gives relevant information to process designers. In this work, the simulation and exergy analysis of large-scale production of magnetite nanoparticles via coprecipitation were performed using computer-aided tools. The process was modeled for the production of 807 t/year of magnetite nanoparticles; the data for the simulation were obtained from the literature, and experimental results were developed by the authors. The exergy efficiency of the process was estimated at 0.046%. The exergy of waste was estimated to be 105 313 MJ/h, while the unavoidable exergy losses were 2941 MJ/h. Washing 2 and 3 represented the most critical stages of the process, contributing 95.12% of the total irreversibilities due to the waste exergy, which corresponds to the water and ethanol exergy discarded in these stages. These results show that the process must be improved from the energy point of view and require the implementation of process optimization strategies to reach a more sustainable design.

Assessment of a Sour Water Treatment Unit Using Process Simulation, Parametric Sensitivity, and Exergy Analysis

In this work, a sour water treatment unit was evaluated combining exergetic analysis and parametric sensitivity analysis. Process simulation was performed using Aspen HYSYS 10.1 following real refinery configurations, and the results were validated with existing data. The parametric sensitivity was evaluated by varying the effect of process variables to identify an alternative case with the best technical performance. The exergy analysis was applied to both base and alternative cases. The outcomes were exergy efficiency by stages, global exergy efficiency, total irreversibilities, and exergy by industrial services. A comparison of both cases was performed to identify opportunities for improvement in real sour water treatment. Results revealed that the overall exergy efficiency for the base case was 44.28%. After improving the technical performance, the overall exergy efficiency decreased to 36.12%; the latter indicated higher irreversibilities due to the increase in the use of industrial services. This finding suggested that those process improvements may affect the performance of this refinery unit from an exergetic point of view.

Process Simulation and Exergy Analysis of a Mercaptan Oxidation Unit in a Latin American Refinery

In this work, the mercaptan oxidation unit of an oil and gas refinery was simulated and assessed using exergy and parametric sensitivity analysis to identify opportunities for improvement from a technical and energy point of view. The process simulation was performed using Aspen HYSYS V10.1 to obtain extended mass and energy balances. The simulation results were validated with the data available in the literature. The effects of operating conditions on technical performance were analyzed via parametric analysis. The exergy analysis was applied to two case studies: the base case and the resulting case from technical improvements. The global exergy efficiency, irreversibilities, exergy of utilities, and efficiencies per stage were calculated to map process equipment with the highest losses of exergy. A comparison between both base and alternative cases was introduced in order to analyze increments in exergy efficiencies. An exergy efficiency of 84.21% was found for the base case, while for the alternative case after applying parametric sensitivity, it was calculated to be 81.95%. This decrease by 2.26% was attributed to the increase of irreversibilities and exergy of wastes to achieve a product with better quality standards.