| 摘要 |
<p>A hydrocarbon chargestock (11) is separated by distillation (12, 16), e.g. at least in part under reduced pressure, into a conversion feedstream (22, 24) and a vacuum residuum (17). The feedstream is converted at an elevated temperature in a conversion unit (25), e.g. a fluidized catalytic cracking system, to high temperature conversion products (26) which are passed into the bottom region of the lower portion (27) of a fractionation tower (28). The vacuum residuum (17) is passed (via 50) into the top of the lower portion (27) of the fractionation tower (28). Heat and mass transfer within the lower portion (27) of the tower desuperheat the conversion products and also strip from the vacuum residuum lower boiling materials thereby increasing the amount of useful hydrocarbon distillates recovered from the tower (28) and decreasing the amount of low value high boiling residue (30) discharged from the bottom of the tower and which is discarded for use as a fuel oil component and/or a feed for a subsequent conversion process (e.g. visbreaking, flexicoking, etc). The amount of cooling of high boiling materials (e.g. in heat exchangers 19, 33) is considerably reduced compared to known hydrocarbon conversion processes.</p> |
