3270
Energy & Fuels 2007, 21, 3270–3273
The Study on Cerium-Supported Spinel Additives for Reducing Olefins in the Fluid Catalytic Cracking (FCC) Gasoline Yan-Jin Ren, Xiao-Feng Wang, and Shi Li* Research Center of Petroleum Processing, East China UniVersity of Science and Technology, Shanghai 200237, People’s Republic of China ReceiVed June 15, 2007. ReVised Manuscript ReceiVed August 14, 2007
The effect of additives for reducing the olefins in the fluid catalytic cracking gasoline was studied in the micro-fixed bed reactor, and the rare-earth Ce was supported on the magnesia–alumina spinel additive. From the X-ray diffraction spectra, it was found that the form of the spinel was suppressed and that different crystal forms were formed with different activation temperatures. The effect of Ce4+ for reducing the olefins is better than that of Ce3+.
Table 1. Compositions of Feedstock
1. Introduction The rapid development of the automotive industry brings about the great increase of fuel consumption, and as a consequence, the air pollution caused by exhaust gas becomes more and more serious.1 For this reason, governments all over the world have been tightening their regulations on the compositions of vehicle fuels. Almost all refineries are forced to change their strategy to meet the new mandatory specifications on gasoline composition with low olefin and sulfur content and high octane number. In China, one of the most serious problems of the gasoline quality is excessive olefin content, which has brought negative influence to the sediment of the engine, the emission of deleterious gas from the engine, and actinochemistry reaction activity of the tail gas. At the beginning of 2005, SINOPEC put forward that, because of the Beijing Olympic Games in 2008 and the World’s Fair in Shanghai in 2010, the two cities were enforced to take the lead in using the European vehicle standard of unleaded gasoline. In China, approximately 80% of gasoline comes from fluid catalytic cracking (FCC) gasoline, in which the olefins content is usually as high as 50–65 vol %.2 At present, however, it is difficult to change the gasoline pool composition remarkably because of the lack of catalytic reforming, alkylation, isomerization, and oxygenous compound-producing units. To meet the government regulations, therefore, it is critical to decrease the olefins content in FCC gasoline. Thus far, although several measurements have been taken to decrease the olefins content, such as operation optimization of FCC units, the application of novel olefins reduction FCC catalysts, and so on, the olefins content in gasoline can be decreased to around 35 vol %,3 which is still much higher than the upper value 18 vol % as regulated by the European vehicle standard of unleaded gasoline. Therefore, it is urgent to develop a novel technique that can preserve the octane value while reducing the olefins content of gasoline. * To whom correspondence should be addressed. Telephone: 86-2164252274. Fax: 86-21-64252386. E-mail:
[email protected]. (1) Zhang, P. Q.; Wang, X. S.; Guo, X. W.; Guo, H. C.; Zhao, L. P.; Hu, Y. K. Catal. Lett. 2004, 92, 63–68. (2) Yu, F.; Xiao, J. B.; Duo, L.; Gang, S.; Wei, S. W.; Jian, X. Fuel 2005, 84, 435–442. (3) Yu, F.; Xiao, J. B.; Gang, S. Catal. Lett. 2005, 105, 67–75.
component
content (wt %)
component
content (wt %)
nonaromatics toluene ethyl benzene p-xylene hexene
