Patent GB-791073-A (GB)
Title: Catalytic hydrocaracking
IPC: C10G47/14
Filed: 1954-04-27
Abstract: Petroleum fractions boiling in the range 400-600 DEG  F. are converted to gasoline by hydrocracking in the presence of hydrogen and of a catalyst consisting of at least one metal of the platinum-palladium series deposited on a carrier consisting of a synthetic composite of solid oxides of at least two elements of Groups IIa, IIIb, IVa and IVb of the Periodic System under the following reaction conditions:- temperatures from 400-825 DEG  F., pressures from 100-2500 lbs. p.s.i., hourly space velocity of from 0.1-10, molar ratio of hydrogen to hydrocarbon charge of 2-80-which are correlated so that there is a net consumption of hydrogen in the process.  The carrier should have an activity index of 25 as described in National Petroleum News 36, pR-536 (August 2nd, 1944). Synthetic composites specified include: silica-alumina, silica-zirconia, silica-alumina-zirconia, silica-alumina-thoria, alumina-boria, silica-magnesia, silica-alumina-fluorine, &c.  The carrier composite may be prepared in bead form, as described in Specification 576,058. Composites containing halogen may be prepared by impregnating the composite with the corresponding ammonium halide and heating to 1000 DEG  F.  The activity of the carrier may be reduced if required by heating with steam or water.  The Figures (not shown) present curves illustrating the relationships (1) between the cracking temperature for 50 per cent conversion to products boiling below 410 DEG  F. and the activity index of the carrier; (2) between yield of dry gas and the catalyst activity index; (3) between temperature and per cent conversion into gasoline and fuel oil; (4) between conversion and space velocities; (5) between the per cent conversion obtained by the process and that of the prior art; (6) between the production of gasoline and methane, ethane and propane; (7) between the yield of dry gas and the per cent conversion to products boiling below 410 F. at different space velocities; (8) between the per cent conversion and the nitrogen content of the charge.  Tables are provided giving the data from which the above curves are plotted.  A catalyst consisting of platinum supported on a silica-alumina carrier is prepared by mixing an aqueous solution of sodium silicate containing 158 gs. silica per litre with an equal amount of an aqueous acid solution of aluminium sulphate containing 39.4 gs. Al2(SO4)3 per litre.  The mixture was dropped through a column of oil wherein gelation of the hydrogel was effected in bead form.  The bead hydrogel was soaked in hot water and the sodium in the hydrogel removed by exchange with a solution of Al2(SO4)3 containing a small amount of ammonium sulphate.  The gel was washed, dried in superheated steam, calcined and crushed to 14-25 mesh.  The carrier was then immersed in an aqueous solution of chloroplatinic acid of the required concentration, excess of solution was removed by centrifuging, the impregnated carrier was dried and treated with hydrogen at 400 DEG  F. and activated in hydrogen at 1000 DEG  F.  A light gas oil was contacted with a catalyst prepared as described above and containing 1.8 per cent platinum in eight runs in which a liquid hourly space velocity of one, a hydrogen pressure of 500 lbs. p.s.i., a hydrogen/hydrocarbon molar ratio of 9.5 were maintained the same in each run but the temperature was stepped up in stages from 410 DEG  in the first run to 902 DEG  F. in the last run. The percentage conversion increased from 50 to a maximum of 100 at 680 DEG  F. and then fell to 70 at 902 DEG  F.  Specifications 657,565 and 686,641 also are referred to.