GB606863A - An improved process for the synthesis of hydrocarbons - Google Patents

Abstract

<PICT:0606863/III/1> In the synthesis of liquid hydrocarbons from CO+H2 using a fluidized catalyst, contaminated catalyst is withdrawn from the reaction zone, either continuously or intermittently, heated to volatilize oily or waxy material, and returned. A stripping gas may be used to assist the volatilization which is effected in a second reaction zone. The reactors 1, 1a are of the usual type wherein the catalyst is kept in a fluidized state by controlling the net upward velocity of the reacting gases at 1/2 -5 ft./sec. for a particle size of 100-400 mesh. Catalyst is withdrawn through lines 3, 3a and cooled in coolers 4, 4a, while reactants are withdrawn through lines 6, 6a, treated to remove residues of catalyst, condensed in coolers 7, 7a and collected in drums 10, 10a. Synthesis gas enters by line 2 and heater 5. Catalyst withdrawn from reactor 1 is in part returned via lines 12 and 2, and in part passed by line 14, after suspension in uncondensed gases from drum 10 supplied by line 15, through heater 20 to reactor 1a. The said gases may first be freed from CO2 in scrubber S, and act to strip oil and wax from the catalyst in reactor 1a which is operated at a lower pressure and higher temperature. Stripping is assisted by gases from drum 10a which are fed via line 22, and heater 24 to reactor 1a, and carry in suspension catalyst recovered from cooler 4a via line 26. Other catalyst from 4a is fed by line 30 to feed line 2 of reactor 1. Gases from 10a may pass by pipe 40 and cooler 41 to a drum 10b. Product and water are separately withdrawn from drums 10, 10a, 10b. Reactor 1a is preferably of about one-third the volume of reactor 1. Suitable catalysts contain cobalt-magnesia-kieselguhr, e.g. 32, 5, 63 per cent by weight, or over 45 per cent iron with, say, 5 per cent oxide of alkali metal, copper or aluminium. With the former, operating conditions in reactor 1 are 375-450 DEG F., 10-150 p.s.i.g., and 500-500 vols./vol./hr.; with the latter, 450-700 DEG F., 50-500 p.s.i.g., and 50-100 vols./vol./hr. In reactor 1a, temperature is 5-100 DEG F. higher, and pressure 10-150 p.s.i.g. lower than in reactor 1, for cobalt catalysts. For iron catalysts, the figures are 5-250 and 50-500. Specification 600,580 is referred to.ALSO:<PICT:0606863/IV(b)/1> In the synthesis of liquid hydrocarbons from CO+H2 using a fluidized catalyst, contaminated catalyst is withdrawn from the reaction zone, either continuously or intermittently, heated to volatilize oily or waxy material and returned. A stripping gas may be used to assist the volatilization which is effected in a second reaction zone. The reactors 1, 1a are of the usual type, wherein the catalyst is kept in a fluidized state by controlling the net upward velocity of the reacting gases at 1/2 -5 p ft./sec. for a particle size of 100-400 mesh. Catalyst is withdrawn through lines 3, 3a, and cooled in coolers 4, 4a, while reactants are withdrawn through lines 6, 6a, treated to remove residues of catalyst, condensed in coolers 7, 7a, and collected in drums 10, 10a. Synthesis gas enters by line 2 and heater 5. Catalyst withdrawn from reactor 1 is in part returned via lines 12 and 2, and in part passed by line 14, after suspension in uncondensed gases from drum 10 supplied by line 15, through heater 20 to reactor 1a. The said gases may first be freed from CO2 in scrubber S, and act to strip oil and wax from the catalyst in reactor 1a which is operated at a lower pressure and higher temperature. Stripping is assisted by gases from drum 10a which are fed via line 22, and heater 24 to reactor 1a, and carry in suspension catalyst recovered from cooler 4a via line 26. Other catalyst from 4a is fed by line 30 to feed line 2 of reactor 1. Gases from 10a may also pass by pipe 40 and cooler 41 to a drum 10b. Product and water are separately withdrawn from drums 10, 10a, 10b. Reactor 1a is preferably of about one-third the volume of reactor 1. Suitable catalysts contain cobalt-magnesia-kieselguhr, e.g. 32, 5, 63 per cent by weight, or over 45 per cent iron with say 5 per cent oxide of alkali metal, copper or aluminium. With the former, operating conditions in reactor 1 are 375-450 DEG F., 10-150 p.s.i.g., and 50-500 vols./vol./hr.; with the latter, 450-700 DEG F., 50-500 p.s.i.g., and 50-1000 vols./vol./hr. In reactor 1a, temperature is 5-100 DEG F. higher, and pressure 10-150 p.s.i.g. lower than in reactor 1, for cobalt catalysts. For iron catalysts, the figures are 5-250 and 50-500. Specification 600,580 is referred to.