Search

Natural gas is a clean fuel and proper feed for chemical industries. However, its transportation to consumer markets is harder and more expensive than that of crude oil because of some specific properties. Therefore, natural gas conversion to chemicals and exporting them instead of gas is safer, and this is also more profitable. Up until now, many methods and alternative techniques have been presented in this field. In this study, three important processes of shale gas conversion to more valuable compounds including gas to liquid (GTL), gas to methanol (GTM), and gas to ethylene (GTE) have been simulated by Aspen HYSYS software. Then the economic parameters of each process have been calculated. Eventually, the initial investment costs for GTM, GTL, and GTE are 422, 249, and 967, respectively. Incommands allowed only within braces addition, the return on investment values for GTM, GTL, and GTE have been estimated as 40, 37, and 20%, respectively.

Polyesters based on polyols have emerged as promising biomaterials for various biomedical applications, such as tissue engineering, drug delivery systems, and regenerative medicine, due to their biocompatibility, biodegradability, and versatile physicochemical properties. This review article provides an overview of the synthesis methods, performance, and biodegradation mechanisms of polyol-based polyesters, highlighting their potential for use in a wide range of biomedical applications. The synthesis techniques, such as simple polycondensation and enzymatic polymerization, allow for the fine-tuning of polyester structure and molecular weight, thereby enabling the tailoring of material properties to specific application requirements. The physicochemical properties of polyol-based polyesters, such as hydrophilicity, crystallinity, and mechanical properties, can be altered by incorporating different polyols. The article highlights the influence of various factors, such as molecular weight, crosslinking density, and degradation medium, on the biodegradation behavior of these materials, and the importance of understanding these factors for controlling degradation rates. Future research directions include the development of novel polyesters with improved properties, optimization of degradation rates, and exploration of advanced processing techniques for fabricating scaffolds and drug delivery systems. Overall, polyol-based polyesters hold significant potential in the field of biomedical applications, paving the way for groundbreaking advancements and innovative solutions that could revolutionize patient care and treatment outcomes. [ABSTRACT FROM AUTHOR]

Many studies focusing on the composition of gasoline with any type of fuel additives have shown that the overall engine performance has a significant impact on reducing emissions. In this research work, ethanol, isopropanol, and diisopropyl ether as oxygenated additive with cerium oxide (CeO2) and iron(III) oxide (Fe2O3) as metal nanoparticles were combined with pure gasoline. Due to the more oxygen they have in their structure, these alcohol additives reduce pollutants and complete combustion. Metal nanoparticles also improve the performance of the engine due to the proper potential. To check the efficiency of the new fuel, a four-stroke engine connected to a dynamometer and an analyzer tested different conditions: speed of 1500 and 2000 rpm and loading percentage of 30 and 40%. Analyzed data include the engine power, and the amount of CO, CO2, HC, and NOx released. The power of the engine on gasoline fuel was 14.43 at 1500 rpm, and once the test was repeated with mixed fuel with additives, it increased to 17.5, which indicates an improvement in engine performance. The amount of CO emissions at 1500 rpm with gasoline fuel was 3.25, and once repeating the test with the same engine rpm with mixed fuel, it decreased to 1.68. The amount of CO2 at 1500 rpm with gasoline fuel was 3.8 and repeating the test with mixed gasoline, it was 5.7. The amount of HC emission with gasoline was 65, and it was 62 when tested with mixed fuel. The amount of NOx released in comparison of gasoline fuel with mixed fuel reached from 264 to 533. The performance improvement and pollutant emissions are fully described in the conclusion section. The analyzed data were calculated and transformed into a model. Among the additives used, isopropanol and CeO2 nanoparticles had better results in optimizing the fuel, reducing the pollutants, and increasing the engine performance. The optimization results show that the use of isopropanol (5%) and CeO2 (1.39 wt. %) as well as diisopropyl ether (4 wt. %) at high engine speed (1504.97 rpm) can be improved engine performance and reduce exhaust gas emissions. [ABSTRACT FROM AUTHOR]

Many studies focusing on the composition of gasoline with any type of fuel additives have shown that the overall engine performance has a significant impact on reducing emissions. In this research work, ethanol, isopropanol, and diisopropyl ether as oxygenated additive with cerium oxide (CeO2) and iron(III) oxide (Fe2O3) as metal nanoparticles were combined with pure gasoline. Due to the more oxygen they have in their structure, these alcohol additives reduce pollutants and complete combustion. Metal nanoparticles also improve the performance of the engine due to the proper potential. To check the efficiency of the new fuel, a four-stroke engine connected to a dynamometer and an analyzer tested different conditions: speed of 1500 and 2000 rpm and loading percentage of 30 and 40%. Analyzed data include the engine power, and the amount of CO, CO2, HC, and NOx released. The power of the engine on gasoline fuel was 14.43 at 1500 rpm, and once the test was repeated with mixed fuel with additives, it increased to 17.5, which indicates an improvement in engine performance. The amount of CO emissions at 1500 rpm with gasoline fuel was 3.25, and once repeating the test with the same engine rpm with mixed fuel, it decreased to 1.68. The amount of CO2 at 1500 rpm with gasoline fuel was 3.8 and repeating the test with mixed gasoline, it was 5.7. The amount of HC emission with gasoline was 65, and it was 62 when tested with mixed fuel. The amount of NOx released in comparison of gasoline fuel with mixed fuel reached from 264 to 533. The performance improvement and pollutant emissions are fully described in the conclusion section. The analyzed data were calculated and transformed into a model. Among the additives used, isopropanol and CeO2 nanoparticles had better results in optimizing the fuel, reducing the pollutants, and increasing the engine performance. The optimization results show that the use of isopropanol (5%) and CeO2 (1.39 wt. %) as well as diisopropyl ether (4 wt. %) at high engine speed (1504.97 rpm) can be improved engine performance and reduce exhaust gas emissions. [ABSTRACT FROM AUTHOR]