| 摘要 |
<p>Selective vaporisation process for reducing the Conradson carbon (CC) and metals content of heavy petroleum fractions comprises contacting the feed and inert gas with a finely divided inert solid material in a riser reactor under mild cracking conditions, including a high temp. and a short hydrocarbon residence time. The vapour-phase prods. are sepd. from the solids and are cooled to a temp. below that at which significant thermal cracking occurs. The solids are contacted with an oxidising gas to burn off coke deposits and heat the catalysts (sic) to high temp., whereupon the heated solids are returned to the lower part of the riser. The improvement comprises introducing the inert gas into the lower part of the riser and injecting the feed into the riser at a point situated in or above the lower part. The process is esp. useful for producing FCC feedstocks from petroleum residua. Injection of the inert gas as above provides provides greater flexibility in the feed injection rate and/or in the control of the residence time in the riser.</p> |
