GB677095A - Process and apparatus for hydrocarbon conversion - Google Patents

Abstract

<PICT:0677095/III/1> <PICT:0677095/III/2> In the conversion of fluid hydrocarbons in the presence of a cyclically moving granular contact material, catalytic or otherwise, which is passed downwardly through the conversion and contact material reconditioning zones, the material is elevated from the base of the reconditioner to the top of the converter and also, if the converter and reconditioner are positioned side by side, from the base of the converter to the top of the reconditioner through a gas-operated lift pipe, at least two streams of lift gas being supplied to the lower end of the lift pipe which is immersed in a bed of the contact material, one of the streams being fed directly to the bottom of the pipe without passing through any substantial thickness of the bed and the other being fed into the solid at a point spaced from the lift pipe so as to convey the solid into the first stream. The solid material entry to the lift pipe is controlled at the desired rate by adjusting the flow of the second stream of gas. The linear velocities of both gas streams are maintained not greatly in excess of nor greatly less than that of the mixed gases in the lift pipe. As shown, contact material is passed as a downwardly moving bed through converter 11 and reconditioner 12. Hydrocarbon feed enters the converter at 36 or 41 and product gases leave at 64. Regenerating gas or cooling or heating gas depending on whether the contact material is catalytic or a heat transfer medium enter the reconditioner at 81 and leave at 88. Contact material from the reconditioner is collected in tank 13 and elevated by steam through lift pipe 14 to hopper and separator 10 from which steam is withdrawn and condensed at 130 thereby creating a partial vacuum in hopper 10 and enabling the tank 13 to be operated at substantially atmospheric pressure. Steam is supplied from line 118 to valved branches 107, 112 and 113, that from branch 107 being discharged directly into the flared lower end of lift pipe 14, Fig. 4, through a distributer 104 and that from branches 112, 113 being discharged through distributer 110, 111 to convey material from the bed 102 through annular passage 106 into the first stream. A three-way valve 117 is designed to correct any adjustment in steam flow through branches 112, 113 by an opposite and equal adjustment in the steam flow through branch 107. In a modification the secondary feeder steam is introduced into tank 13 above the bed 102 in which case the pressure in the tank may be above atmospheric, and a suction-type lift is not employed. Instead of steam as a lift gas other condensible or alternatively non-condensible gases may be employed in which latter case the barometric condenser 130 is replaced by a vacuum pump. The process is applicable to catalytic cracking, isomerization, hydrogeneration, reforming, dehydrogenative aromatization, hydroforming and desulphurization of petroleum fractions and high temperature pyrolytic conversions such as the conversion of propane and ethylene or of methane to acetylene.