3352.     ---------------.  [TECHNICAL OIL MISSION.]  [Hydrocarbon Synthesis With Iron Catalysts, Leuna Works, Apr. 5, 1940.]  Transl. of German documents on the Development of Iron Catalysts for the Fischer-Tropsch Synthesis.  Part II, 1946, pp. 27-40; TOM Reel 134, item B-23 (1st half).

        Details are presented of the experimental investigation of 3 Fe catalysts:  A fused Fe catalyst (997); a sintered Fe catalyst (Michael); and a Leuna NH₃ catalyst (WK 17), each reduced with H₂ at atmospheric pressure at temperatures 450°-850° for relative periods of 5-15 days.  The converters were tube furnaces (the tubes 15 mm. diam.) with Dowtherm as the heat transfer medium.  A synthesis gas of composition CO:H₂ = 1:2.6 was used, except when operating at 20 atm. when the composition was 1.2:1.  Reduction at the lower temperatures produces more active catalysts, although not much is gained by going below 450°.  When 2 catalysts of the same composition but reduced at 2 different temperatures were used, the one reduced at the lower temperature gave a lower-boiling product than the one reduced at the higher temperature.  Higher space velocity and synthesis temperature also have a tendency to increase the yield of low-boiling constituents.  In comparing the products formed on Co catalysts at middle and atmospheric pressures and a space velocity of 100 with those produced from a sintered Fe catalyst at 20 atm. and a space velocity of 200, it is seen that the latter gives better benzine yields than the former.  An essential feature in the synthesis with Co is the comparatively high yield of paraffins in the benzine fraction (86% paraffins, 14% olefins), whereas the products from the Fe catalyst contain considerably greater amounts of unsaturates (approximately 50% olefins, 45% paraffins).  The effect of this increased olefin content is to raise the octane number of the benzine fraction.  Of 3 catalysts examined, a Co catalyst, WK17 and 997, the latter produced the highest olefin content with the highest octane number (71%, as compared with 15 and 48T and 63.5%, as compared with 25 and 57%).  It is pointed out, however, that factors other than the olefin content influence the octane number.  In general, for the same olefin content of the benzine fraction, a high reaction temperature, a high space velocity, and an active catalyst, in other words, all factors that favor the formation of low-boiling constituents, will yield a product having the highest octane number.  Also, an increase in the olefin content is accompanied by a decrease in the boiling point of the product.  Some data are presented on the behavior of several fused Fe catalysts under specific synthesis conditions of 19 atm. pressure and 200 space velocity, and X-ray investigations were made to determine the nature of C deposition on the catalyst.  It is believed that it takes place according to the equation 2CO→CO₂+C and 4CO+3Fe→Fe₃O₄+4C.  A 2-stage operation was performed with a Co catalyst in the second stage at atmospheric pressure.  The result was a conversion of 86% and a total yield from both stages of 135-150 gm. per m.³ of water gas.