Mesoporous zeolites as efficient catalysts for oil refining and natural gas conversion
ABSTRACT Zeolites have been regarded as one of the most important catalysts in petrochemical industry due to their excellent catalytic performance. However, the sole micropores in zeolites severely limit their applications in oil refining and natural gas conversion. To solve the problem, mesoporous zeolites have been prepared by introducing mesopores into the zeolite crystals in recent years, and thus have the advantages of both mesostructured materials (fast diffusion and accessible for bulky molecules) and microporous zeolite crystals (strong acidity and high hydrothermal stability). In this review, after giving a brief introduction to preparation, structure, and characterization of mesoporous zeolites, we systematically summarize catalytic applications of these mesoporous zeolites as efficient catalysts in oil refining and natural gas conversion including catalytic cracking of heavy oil, alkylation, isomerization, hydrogenation, hydrodesulfurization, methane dehydroaromatization, methanol dehydration to dimethyl ether, methanol to olefins, and methanol to hydrocarbons.
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ABSTRACT: High demand for diesel fuel has attracted researchers to revisit some refining processes. Hydrocracking and oligomerization are two targeted processes to produce diesel intensively. In this minireview, challenges in the acid-catalyzed oligomerization of olefins are briefly discussed. One-dimensional pore zeolites have been identified as potential catalytic materials for oligomerization. However, one-dimensional pore zeolites mostly suffer from a long diffusion path due to high crystal aspect ratio (length/width). Mass-transfer limitation are resolved by the development of more efficient catalysts; nanosized and hierarchical zeolites with the one-dimensional pore system such as TON, MTT, and MTW.Industrial & Engineering Chemistry Research 01/2015; 54(3):781-789. DOI:10.1021/ie5041226 · 2.24 Impact Factor
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ABSTRACT: This paper presents a sub-pilot scale process of synthesis of Na-P1 zeolite from the coal fly ash. After establishing the appropriate synthesis conditions (20 kg of fly ash, 12 kg of NaOH, 90 dm3 of water, the reaction temperature: 80 �C and reaction time: 36 h), the high purity (81 wt%) Na-P1 zeolite product was obtained. Its chemical, mineralogical, and textural properties were determined (by means of XRD, XRF, SEM–EDS and ASAP 2020). The synthesized material has a specific BET surface area (88 m2/g) c.a. six times higher than the fly ash from which it has been derived (15 m2/g). The pore-size distribution indicates a mesoporous character of the obtained zeolite, with the following pores size contents: micropores (2.76 %), mesopores (61.81 %), and macropores (35.43 %). The presented technological/production line is fully automated and allows to regulate the conditions of the synthesis process, therefore different types of zeolite materials (including: Na-X, Linde-A, and Na-P1) can be obtained using the same equipment.Clean Technologies and Environmental Policy 01/2014; 16(6):1217–1223. DOI:10.1007/s10098-014-0719-6 · 1.67 Impact Factor
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ABSTRACT: The paper presents the possibilities of using synthetic zeolites in environmental protection and engineering. As a result of the synthesis reaction of fly ash, the following types of zeolites were obtained: Na-X, Na-P1, sodalite, and two mixtures of zeolites composed of Na-P1/Na-X/Linde-A and Na-P1/Linde-A. Obtained zeolites were tested on the removal of ammonium ions from water, radionuclides (226Ra and 228Ra) from mine water, zinc ions from washing baths, CO2 from exhaust gases, and oil refining. In the case of ammonium ion removal, the uptake of these ions from aqueous solutions increases with the increase in the initial concentration of NH4+ in the tested artificial solution. The tests of radionuclides removal have shown high efficiency that reached 98%. The analysis of purification washing baths results indicate Zn2+ high removal efficiency of the tested zeolite. Zeolites are a bit less effective at removing CO2. However, they were very good materials in oil refining where the obtained results are slightly better than for the adsorbents used commercially for this purpose. The results showed that, in most cases, the zeolites tested remove the aforementioned contaminants very effectively, and are a competing material for various kinds of commercially available adsorbents used for the described impurities.Fresenius Environmental Bulletin 01/2015; 24(3a):854-866. · 0.53 Impact Factor