Irregularly shaped non-spherical supported catalyst, and a process for hydroconverting heavy oil fractions

Abstract

The present invention concerns a catalyst for hydrotreating and/or hydroconverting heavy metal-containing hydrocarbon feeds, said catalyst comprising a support in the form of mainly irregular and non-spherical alumina-based agglomerates the specific shape of which results from a crushing step, and containing at least one catalytic metal or a compound of a catalytic metal from group VIB and/or group VIII (groups 8, 9 and 10 of the new periodic table notation), optionally at least one doping element selected from the group constituted by phosphorus, boron and silicon (or silica which does not form part of that which may be contained in the selected support) and halogens, said catalyst essentially being constituted by a plurality of juxtaposed agglomerates each formed by a plurality of acicular platelets, the platelets of each agglomerate generally being oriented radially with respect to each other and with respect to the centre of the agglomerate. The specific shape of the catalyst improves its performance when using it for hydroconverting/hydrotreating heavy metal-containing hydrocarbon feeds. The invention also concerns the use of said catalyst alone or as a mixture in a fixed bed or ebullated bed reactor.

1 . A catalyst comprising an alumina-based support, at least one catalytic metal or compound of a catalytic metal from group VIB and/or VIII, the pore structure of which is composed of a plurality of juxtaposed agglomerates and each formed by a plurality of acicular platelets, the platelets of each agglomerate generally being oriented radially with respect to the others and with respect to the centre of the agglomerate, said support having an irregular and non-spherical shape and being mainly in the form of fragments obtained by crushing alumina beads, and prepared by a process including the following steps:
 a) granulation starting from an active alumina powder having a low crystallinity and/or amorphous structure, to obtain agglomerates in the form of beads;   b) maturing said beads in a moist atmosphere between 60° C. and 100° C. then drying said beads;   c) sieving resultant dried beads to recover a fraction of said beads;   d) crushing said fraction;   e) calcining at least a portion of said crushed fraction at a temperature in the range of 250° C. to 900° C.;   f) impregnating resultant calcined crushed fraction with acid and hydrothermal treatment at a temperature in the range of 80° C. to 250° C.;   g) drying resultant acidified and hydrothermally treated fraction then calcining at a temperature in the range 500° C. to 1100° C. to obtain said support.   
   
   
       2 . A catalyst according to  claim 1 , exhibiting a loss on attrition, quantified in accordance with the ASTM D4058-96 standard, is less than 5% by weight. 
   
   
       3 . A catalyst according to  claim 1 , exhibiting a loss on attrition, quantified in accordance with the ASTM D4058-96 standard, is less than 2% by weight. 
   
   
       4 . A catalyst according to  claim 1 , having a crush strength, measured using the Shell method in accordance with standard SMS 1471-74, of at least 1.5 MPa.  
   
   
       5 . A catalyst according to  claim 1 , in which granulation step a) is conducted with at least one pore-forming agent. 
   
   
       6 . A catalyst according to  claim 1 , comprising at least one catalytic metal or a compound of a catalytic metal from group VIB. 
   
   
       7 . A catalyst according to  1 , comprising at least one catalytic metal or a compound of a catalytic metal from group VIII (columns 8, 9 and 10 of the new periodic table notation). 
   
   
       8 . A catalyst according to  claim 1 , further containing at least one doping element selected from the group constituted by phosphorus, boron, silicon and the halogens. 
   
   
       9 . A catalyst according to  claim 1 , wherein the support in the form of fragments has a size such that the diameter of a sphere circumscribing at least 80% of said fragments is in the range of 0.05 to 3 mm. 
   
   
       10 . An ebullated bed comprising a catalyst according to  claim 9 , in which the diameter of the circumscribing sphere is in the range of 0.3 to 1.5 mm. 
   
   
       11 . A fixed bed comprising a catalyst according to  claim 9 , in which the diameter of the circumscribing sphere is in the range 1.0 to 2.0 mm. 
   
   
       12 . A catalyst according to claims  claim 1 , in which the amount of group VIB metal, expressed as the % by weight of oxide with respect to the final catalyst weight, is in the range of 1% to 20% and in which the amount of group VIII metal, expressed as the % by weight of oxide with respect to the final catalyst weight, is in the range of 0 to 10%. 
   
   
       13 . A catalyst according to  claim 12 , in which the group VIB metal is molybdenum and the group VIII metal is nickel. 
   
   
       14 . A catalyst according to  claim 1 , containing an amount of non noble group VIII metal in the range of 1% to 4% by weight. 
   
   
       15 . A catalyst according to  claim 1 , containing a doping element comprising phosphorus and the amount of phosphorus, expressed as a % by weight of oxide with  respect to the final catalyst weight, is in the range of 0.3% to 10%. 
   
   
       16 . A catalyst according to  claim 15 , in which the amount of phosphorus is in the range of 1.2% to 4% by weight. 
   
   
       17 . A catalyst according to  claim 1 , further containing at least one doping element selected from the group formed by boron, silicon and the halogens in amounts, expressed as the % by weight of oxide with respect to the final catalyst weight, of less than 6% for boron, less than 5% for the halogens and in the range of 0.1% to 10% for silicon. 
   
   
       18 . A catalyst according to  claim 1 , having a pore distribution, determined by the Hg porosimetry technique, as follows:
 % of total pore volume as pores with a mean diameter of less than 100 Å: between 0 and 10   % of total pore volume as pores with a mean diameter between 100 and 1000 Å: between 40 and 90   % of total pore volume as pores with a mean diameter between 1000 and 5000 Å: between 5 and 60   % of total pore volume as pores with a mean diameter between 5000 and 10000 Å: between 5 and 50   % of total pore volume as pores with a mean diameter of more than 10000 Å: between 5 and 20.   
   
   
       19 . A catalyst according to  claim 1 , having a settled packing density in the range of 0.35 to 0.80 g/cm 3  and a total pore volume, determined by mercury porosimetry, in the range of 0.4 to 1.8 g/cm 3 . 
   
   
       20 . A catalyst according to  claim 1 , having a pore diameter at VHg/2 in the range of 300 to 700 Å. 
   
   
       21 . A catalyst according to  claim 1  in which, in granulation step a), the active alumina powder is moistened with an aqueous solution, then resultant moistened powder is agglomerated in a granulator. 
   
   
       22 . A catalyst according to  claim 1 , in which  in step f), the crushed fraction is impregnated with an aqueous solution comprising at least one acid which can dissolve at least a portion of the alumina of the support, and with at least one compound, distinct from said acid, supplying an anion which is capable of combining with aluminium ions in solution. 
   
   
       23 . A catalyst according to  claim 1 , further comprising impregnating the support obtained at the end of step g) with at least one solution of at least one catalytic metal and optionally at least one dopant. 
   
   
       24 . A catalyst according to  claim 23 , wherein after impregnation of the support, the moist solid is left in a moist atmosphere at a temperature in the range of 10° C. to 80° C., the moist solid obtained is dried at a temperature in the range 60° C. to 150° C. and the solid obtained is calcined after drying at a temperature in the range 150° C. to 800° C. 
   
   
       25 . A process for catalytically hydrotreating and/or hydroconverting heavy metal-containing hydrocarbon feeds the improvement wherein the catalyst is according to  claim 1 . 
   
   
       26 . A process according to  claim 25 , in which said catalyst is provided in an ebullated bed mode at a temperature in the range of 320° C. to 470° C., at a partial pressure of hydrogen of between 3 MPa and 30 MPa, at a space velocity of about 0.1 to 10 volumes of feed per volume of catalyst per hour, and with a ratio of gaseous hydrogen to liquid hydrocarbon feed in the range of 100 to 3000 normal cubic meters per cubic meter. 
   
   
       27 . A process according to  claim 25 , in which said catalyst is provided in an ebullated bed mode at a temperature in the range of 320° C. to 450° C., at a partial pressure of hydrogen of between 3 MPa and 30 MPa, at a space velocity of about 0.05 to 5 volumes of feed per volume of catalyst per hour, and with a ratio of gaseous hydrogen to liquid hydrocarbon feed in the range of 200 to 5000 normal cubic meters per cubic meter. 
   
   
       28 . A process according to  claim 23 , in which said catalyst is partly in the form of fragments and partly in the form of beads or in the form of cylindrical extrudates.