Liquefaction And Gasification Synthesis

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Liquefaction and gasification in supercritical water (SCW) are two processes for transferring substances into liquid and gaseous fuels, which is special for high moisture substances6. Supercritical water, which is serve as the solvent and the reactant in these reactions, mainly decreases mass transition restrictions in ambient condition water; therefore, it helps to accelerate the chemical reactions largely9. However, the vaporization of water along with raw materials is required by traditional pyrolysis and gasification method to convert high-moisture substances, which causes lowering thermal efficiency2. Recent researches have shown that SCW method of gasification produces enormous amount of tar waste water, which have toxic substances such …show more content…
They used TEM, BET specific surface area, X-ray photoelectron spectrum (XPS) and X-ray diffraction (XRD) to analyses physico-chemical properties of the catalyst. In addition, the catalytic activity, dimer inhibition, stability, and a kinetic model are analyzed to gives further evidence of the effectiveness SCWG of phenol. The results of their experiment show that Ru/CeO2 effectively assisted for converting phenol to gaseous fuels CH4 and H2 in supercritical water. Moreover, The efficiency of carbon was progressed to about 90% in the supercritical water phenol gasification with '0.5 g/g Ru/CeO2 and 5 wt% loading of phenol in a water of density 0.0979 g/cm3 at 550 C '. Furthermore, the yields of gaseous fuels with the presence of the catalyst were raised from 60% to 150% at 500 ºC. Additionally, during 5 min the yield was raised to over 100%, which indicates that water may forms 50% of the gaseous products. Moreover, the results illustrates that Ru/CeO2 catalyst assists to improve hydrogenation reactions and inhibit dimers information such as polycyclic aromatic hydrocarbons. Guan et al have explained that the reason for inhibition of dimers and PAHs is that phenol hydrogenation produces cyclohexanol and cyclohexanone radicals, which likely to be absorbed to the decreased surface of Ru before reacting with water to make gaseous products rather than …show more content…
It is reliable because it is from Chemical Engineering Journal and it has written by many authors. The authors used supporting evidence and previous work to support their work. They used many techniques and equipment to make their work accurate. In addition, the main strength is that they explain each step of their experiment by chart, table, or figure, which makes this article easy to understand. The main limitation of this article is that it mentioned treatment phenol only, but what about other toxic substances. Furthermore, the pathways of phenol hydrogenation was still speculated. There is no evidence to establish it. Furthermore, in the future study, it is better to create another catalyst, but it has the same Ru properties and activity. The reason is that Ru catalyst is very expensive. In short, Ru/CeO2 SCWG system may a good method of treating any toxic substances.

To conclude, this article describes gasification in supercritical water to treat tar waste water such as phenol by using Ru/CeO2 catalyst because it assists to improve the efficiency of gasification and to inhibit the formation of dimer. The results of experiment show that Ru/CeO2 SCWG system is a good method to treat phenols. Another aspect this article discuses is the uses of SCW in field of chemistry such as use in organic synthesis, use in powder technology of inorganic substances, and use in chemical

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