Continuous production of propylene in high yield, by direct cracking of light olefinic hydrocarbon charge over moving bed of zeolite catalyst, with simultaneous removal and oxidative regeneration of catalyst

摘要

Direct conversion of light olefinic hydrocarbon (I) into propylene by cracking over specific supported zeolite catalyst (A) involves: (1) circulating (I) at 480-620 [deg]C through reactor over moving bed of granular (A), while withdrawing (A) containing carbon deposits from lower part of reactor; (2) subjecting withdrawn (A) to controlled oxidation; and (3) reintroducing treated (A) into upper part of reactor. Direct conversion of a light olefinic hydrocarbon charge (I), containing at least 80 wt. % up to 12C hydrocarbons, into propylene by catalytic cracking is carried out over a supported zeolite catalyst(s) (A) containing silicon and aluminum at Si/Al ratio 40-130 and showing shape selectivity, selected from zeolites of the MEL, MFI, NES, EUO, FER, CHA or MFS structural type and zeolites NU-85, NU-86, NU-88 or IM-5. (I) is circulated at 480-620 [deg]C through at least one reactor over a moving bed of granular (A), while continuously or discontinuously withdrawing a flow of (A) containing carbon deposits from the lower part of the reactor. The withdrawn (A) is transferred to a regeneration zone, in which it is subjected to at least one controlled oxidation stage. The treated (A) (having a reduced degree of carbon deposition) is then reintroduced, directly or indirectly and downstream of the regeneration zone, into the upper part of the reactor.