separation techniques
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Separations ◽  
2022 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Odi Fawwaz Alrebei ◽  
Abdulkarem I. Amhamed ◽  
Muftah H. El-Naas ◽  
Mahmoud Hayajnh ◽  
Yasmeen A. Orabi ◽  
...  

Gas turbines must now comply with much stricter emission control regulations. In fact, to combat the greenhouse effect, regulatory authorities have drastically reduced allowable emission levels. For example, in less than 12 years, the United States’ Clean Air Act issued the New Source Performance Standards (NSPS), which tightened the NOx emission margin of natural gas combustion (from 75 ppm to 10 ppm). On the other hand, despite those efforts, the high demand for energy produced by fossil-fueled gas turbines in power plants has resulted in dramatic increases in anthropogenic CO2 and NOx emitted by gas combustors. Most systems responsible for these undesirable emissions are directly linked to power generation, with gas turbines playing a pivotal role. Yet, gas turbines are still widely used in power plants and will continue to meet the growing demand. Therefore, sequestration and separation techniques such as Carbon Capture and Storage (CCS) and Air Separation Units (ASU) are essential to reduce CO2 and NOx emissions while allowing large amounts of power to be generated from these systems. This paper provides an in-depth examination of the current state of the art in alternative working fluids utilized in the power generation industry (i.e., gas turbines, combustion). In addition, this paper highlights the recent contribution of integrating separation techniques, such as air separation, steam methane reforming, and water-gas shifting, to the power generation industry to facilitate a continuous and adequate supply of alternative working fluids.


2022 ◽  
pp. 141-170
Author(s):  
María José Trujillo-Rodríguez ◽  
Idaira Pacheco-Fernández ◽  
Verónica Pino

2021 ◽  
pp. 1-19
Author(s):  
Michał Szumski ◽  
Bogusław Buszewski

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3407
Author(s):  
Catarina S. M. Martins ◽  
Helena B. A. Sousa ◽  
João A. V. Prior

AgNPs have exceptional characteristics that depend on their size and shape. Over the past years, there has been an exponential increase in applications of nanoparticles (NPs), especially the silver ones (AgNPs), in several areas, such as, for example, electronics; environmental, pharmaceutical, and toxicological applications; theragnostics; and medical treatments, among others. This growing use has led to a greater exposure of humans to AgNPs and a higher risk to human health and the environment. This risk becomes more aggravated when the AgNPs are used without purification or separation from the synthesis medium, in which the hazardous synthesis precursors remain unseparated from the NPs and constitute a severe risk for unnecessary environmental contamination. This review examines the situation of the available separation methods of AgNPs from crude suspensions or real samples. Different separation techniques are reviewed, and relevant data are discussed, with a focus on the sustainability and efficiency of AgNPs separation methods.


2021 ◽  
Author(s):  
Jawaher Almorihil ◽  
Aurélie Mouret ◽  
Isabelle Hénaut ◽  
Vincent Mirallès ◽  
Abdulkareem AlSofi

Abstract Gravity settling represents the main oil-water separation mechanism. Many separation plants rely only on gravity settling with the aid of demulsifiers (direct or reverse breakers) and other chemicals such as water clarifiers if they are required. Yet, other complementary separation methods exist including filtration, flotation, and centrifugation. In terms of results and more specifically with respect to the separated produced-water, the main threshold on its quality is the dispersed oil content. Even with zero discharge and reinjection into hydrocarbon formations, the presence of residual oil in the aqueous phase represents a concern. High oil content results into formation damage and losses in injectivity which necessitates formation stimulations and hence additional operational expenses. In this work, we investigated the effects of different separation techniques on separated water quality. In addition, we studied the impact of enhanced oil recovery (EOR) chemicals on the different separation techniques in terms of efficiency and water quality. Based on the results, we identified potential improvements to the existing separation process. We used synthetic well-characterized emulsions. The emulsions were prepared at the forecast water: oil ratio using dead crude oil and synthetic representative brines with or without the EOR chemicals. To clearly delineate and distinguish the effectiveness of different separation methods, we exacerbated the conditions by preparing very tight emulsions compared with what is observed on site. With that, we investigated three separation techniques: gravity settling, centrifugation, and filtration. First, we used Jar Tests to study gravity settling, then a benchtop centrifuge at two speeds to evaluate centrifugation potential. Finally, for filtration, we tested two options: membrane and deep-bed filtrations. Concerning the water quality, we performed solvent extraction followed by UV analyses to measure the residual oil content as well as light transmission measurements in order to compare the efficiency of different separation methods. The results of analyses suggest that gravity settling was not efficient in removing oil droplets from water. No separation occurred after 20 minutes in every tested condition. However, note that investigated conditions were severe, tighter emulsions are more difficult to separate compared to those currently observed in the actual separation plant. On the other hand, centrifugation significantly improved light transmission through the separated water. Accordingly, we can conclude that the water quality was largely improved by centrifugation even in the presence of EOR chemicals. In terms of filtration, very good water quality was obtained after membrane filtration. However, significant fouling was observed. In the presence of EOR chemicals, filtration lost its effectiveness due to the low interfacial tension with surfactants and water quality became poor. With deep-bed filtration, produced water quality remained good and fouling was no longer observed. However, the benefits from media filtration were annihilated by the presence of EOR chemicals. Based on these results and at least for our case study, we conclude that centrifugation and deep-bed filtration techniques can significantly improve quality of the separated and eventually reinjected water. In terms of the effects of EOR chemicals, the performance of centrifugation is reduced while filtrations are largely impaired by the presence of EOR chemicals. Thereby, integration of any of the two methods in the separation plant will lead to more efficient produced-water reinjection, eliminating formation damage and frequent stimulations. Yet, it is important to note that economics should be further assessed.


AAPS Open ◽  
2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Deanna J. Nelson ◽  
G. Dean Marbury

AbstractIon chromatography (IC) has evolved into one of the most widely used separation techniques of analytical chemistry. Consequently, the number of users of this method is continuously growing. Analysts often assume that widely used guidelines for HPLC method validation in regulated environments routinely apply to IC. This manuscript provides an analysis of the potential shortcomings of traditional approaches to development and validation of IC methods using suppressed conductivity detection and a risk-based alternative approach to these activities. The goal of the alternative approach is a reduction in the risk of erroneous determinations of analytes when IC methods using suppressed conductivity detection are employed.


2021 ◽  
pp. 405-429
Author(s):  
José Alberto Fracassi da Silva ◽  
Alexandre Zatkovskis Carvalho ◽  
Emanuel Carrilho ◽  
Dosil Pereira de Jesus ◽  
Marcone Augusto Leal de Oliveira

2021 ◽  
pp. 1-8
Author(s):  
R. Das

In this chapter, a summary of different synthetic polymers-based water/gas separation techniques is given. It includes the separation of solutes from wastewater and also the purification of gases from various cocktails. Moreover, a summary of individual chapters of this book entitled ‘Polymeric Membranes for Water Purification and Gas Separation’ is shown in the conclusion section.


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