Regenerating hydrocarbon conversion catalyst - contg. carrier, platinum gp. metal and chlorine in two combustion zones, oxychlorination zone and calcination zone

摘要

Catalyst for reforming or prepn. of aromatic hydrocarbons in at least two steps which comprises a carrier, a noble metal of the Pt gp., and Cl is regenerated in four steps. The regenerator comprises, from top to bottom, (A) a 1st combustion zone with mobile and radial bed, (B) a 2nd combustion zone with mobile and radial bed, (C) a zone with mobile, axial (oxy) chlorination bed, and (D) a zone with axial, mobile calcination bed.(A), (B) (C) and (D) are at 3-8 bars, essentially the same pressure as in the 1st reactor. The catalyst is treated in (a) (A) at 350-450 deg.C, with a combustion gas comprising an inert gas with 0.01-1 vol.% of O2, from a later wash zone, in (b) at a temp. at least 20 deg.C above that in (A), in presence of gas issuing from (A) and of additional inert gas contg. up to 20 vols. % of O2, in such a way that the catalyst is in contact with a gas contg. 0.01-1 vol. % O2. (c) the combustion gas from (B) is withdrawn and divided into (i) a 1st part, 80-90 vols.% of the whole combustion gas, being mixed with gas from the oxychlorination zone, with the mixt. fed into a wash circuit and a drying zone, and (ii) a 2nd part, 20-10% of the whole, being mixed with an inert gas contg. O2 and with Cl or a Cl cpd., to form an oxychlorination gas contg. 1-4 vols.% of O2. (d) the catalyst is treated in (C) with the oxychlorination gas and 350-550 deg.C, and the gas is withdrawn and mixed with the gas from (B), (e) the catalyst is is treated in (D) at 350-500 deg.C bars, with (part of) the gas from the wash circuit and drier, with addn. of fresh air, so that the gas fed into the calcination zone contains 1-10 vols. of O2 and not more than 100 ppm of water vapour, and (f) the other part of the gas from the wash circuit is used in stage (a) as combustion gas. USE/ADVANTAGE - The catalyst is esp. used in reforming of hydrocarbons, in prepn. of aromatic hydrocarbons, esp. benzene, toluene and xylenes, from unsatd. benzenes, etc.