Exploitable results SULFUR REMOVAL FROM FCC GASOLINE; SURENA The objective of the SURENA project is the development of a new FCC catalyst or additive which can produce above 40 % of sulfur reduction in the full range gasoline fraction during the cracking reaction, with minimal detrimental effects on product yields. Taking into account that the major source (90%+) of sulfur in the gasoline pool is the FCC naphtha which amounts from one-third to 50% of the total., it is clear that a reduction of FCC gasoline sulfur will contribute in a large extension to reduce environmentally detrimental emissions. A number of different additives and FCC catalyst modifications have been prepared and tested by the partners. As a consequence of this work some promising materials from the efficacy for sulfur reduction in the naphtha range point of view have been detected. The final sulfur reduction was about 40 % compared to the control FCC catalyst at MAT and pilot plant level. However initial work at FCC pilot plant level has shown a negative effect of operating conditions on the sulphur reduction capability of the most active additives tested at MAT level. It has been established that only by increasing hydrogen transfer reaction rate could be possible to improve sulphur reduction during the cracking process itself and to produce a naphtha containing less sulphur. Among the different factors affecting hydrogen transfer reaction rate are operating conditions, catalyst or additive hydrogen transfer capability and the third aspect to have some influence on this type of reaction is feedstock quality. All these alternatives have been checked during the project development. This phenomenon was confirmed after getting a sulfur reduction in naphtha of about 50% referred to the base catalyst free of additive and without addition of a hydrogen donor to the FCC feedstock. However the result has not been reproduced yet because some unknown variables have negatively affected the sulfur reduction activity of the additives in other later experiments. Another limitation of this technology is the silica migration from the FCC catalyst to the alumina based additives which has permitted to establish the negative effect of this migration on the final sulphur reduction in the gasoline. A higher addition rate should be necessary to maintain the activity or by using an alumina binder or perhaps no binder at all if a pure additive particle has sufficient integrity to withstand process handling. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
