Integrated fluid catalytic cracking process for obtaining hydrocarbon blends having a high quality as fuel

Abstract

The present invention relates to an integrated fluid catalytic cracking process (FCC) which allows hydrocarbon blends to be obtained having a high quality as fuel. In particular, it relates to an integrated process comprising a fluid catalytic cracking step wherein hydrocarbon cuts of an oil origin are converted into blends with a high content of light cycle oil (LCO) having a high quality in terms of density and nature of the aromatic products contained, which, after a separation and a hydrotreating step, is subjected to upgrading by treatment with hydrogen and a catalyst comprising one or more metals selected from Pt, Pd, Ir, Ru, Rh and Re and a silicoaluminate of an acidic nature.

1 . An integrated process for the conversion of hydrocarbon cuts of an oil origin, into hydrocarbon blends having a high quality as fuel, which comprises the following steps:
 subjecting the hydrocarbon cut to fluid catalytic cracking (FCC) to produce Light Cycle Oil (LCO),   subjecting the Light Cycle Oil to hydrotreating,   reacting the hydrotreated Light Cycle Oil obtained in the previous hydrotreatment step with hydrogen in the presence of a catalytic system comprising:
 a) one or more metals selected from Pt, Pd, Ir, Ru, Rh and Re 
 b) a silicoaluminate of an acidic nature, selected from a zeolite belonging to the MTW family and a completely amorphous micro-mesoporous silico-alumina, having a SiO 2 /AL 2 O 3  molar ratio ranging from 30 to 500, a surface area greater than 500 m 2 /g, a pore volume ranging from 0.3 to 1.3 ml/g, an average pore diameter smaller than 40 Å. 
   
     
     
         2 . The process according to  claim 1 , comprising the following steps:
 1) subjecting a hydrocarbon cut to fluid catalytic cracking (FCC) to produce a blend containing LCO,   2) subjecting the blend resulting from the previous FCC step to separation, in order to separate at least one LCO fraction and an HCO fraction,   3) possibly re-feeding at least a part of the HCO fraction to the FCC step;   4) subjecting the LCO fraction to hydrotreatment;   5) reacting the product resulting from step (4) with hydrogen in the presence of a catalytic system comprising:   a) one or more metals selected from Pt, Pd, Ir, Ru, Rh and Re   b) a silicoaluminate of an acidic nature selected from a zeolite belonging to the MTW family and a completely amorphous micro-mesoporous silico-alumina having an SiO 2 /Al 2 O 3  molar ratio ranging from 30 to 500, a surface area greater than 500 m 2 /g, a pore volume ranging from 0.3 to 1.3 ml/g, an average pore diameter smaller than 40 Å.   
     
     
         3 . The process according to  claim 1  or  2 , wherein the hydrocarbon cuts of an oil origin treated in the first step of the integrated process are gas oil, vacuum gas oil, atmospheric residues, thermal cracking products and hydro-cracking residues. 
     
     
         4 . The process according to  claim 1 ,  2  or  3 , wherein the fluid catalytic cracking step is carried out at a temperature ranging from 450 to 650° C., a pressure in the reaction area ranging from 1.3 to 4.5 kg/cm 2  and a catalyst/oil ratio of between 1 and 10 kg/kg, a residence time of the vapours in the reaction area of between 0.5 and 10 seconds. 
     
     
         5 . The process according one or more of the previous claims, wherein the fluid catalytic cracking step is carried out at a temperature within the range of 490 to 530° C. 
     
     
         6 . The process according to one or more of the claims from 1 to 5, wherein in the fluid catalytic cracking step the pre-heating temperature of the feedstock is within the range of 240 to 350° C. 
     
     
         7 . The process according to  claim 2 , wherein the HCO fraction obtained from the separation is at least partially recycled to the FCC step. 
     
     
         8 . The process according to  claim 1  or  2 , wherein the hydrotreatment is carried out in the presence of a catalyst based on metal compounds of Group VI and/or Group VIII on a carrier. 
     
     
         9 . The process according to  claim 1  or  2 , wherein the hydrotreatment is carried out at a temperature ranging from 200 to 400° C. 
     
     
         10 . The process according to  claim 9 , wherein the temperature ranges from 330 to 380° C. 
     
     
         11 . The process according to  claim 1  or  2 , wherein the pressure ranges from 20 to 100 bar in the hydrotreatment step. 
     
     
         12 . The process according to  claim 11 , wherein the pressure ranges from 40 to 80 bar. 
     
     
         13 . The process according to  claim 1  or  2 , wherein the component of an acidic nature (b) is a silico-alumina having an SiO 2 /AL 2 O 3  molar ratio ranging from 50 to 300. 
     
     
         14 . The process according to  claim 1  or  2 , wherein the component of an acidic nature (b) is a silico-alumina having a porosity ranging from 0.4 to 0.5 ml/g. 
     
     
         15 . The process according to  claim 1  or  2 , wherein the component of an acidic nature (b) is a microporous silico-alumina having an XRD spectrum from powders which has no crystalline structure and shows no peaks. 
     
     
         16 . The process according to  claim 1  or  2 , wherein the metal of component (a) is selected from platinum, iridium or mixtures thereof. 
     
     
         17 . The process according to  claim 1  or  2 , wherein the metal, or the mixture of metals, of component (a) is in a quantity ranging from 0.1 to 5% by weight with respect to the total weight of the catalytic composition, wherein the weight percentage of the metal, or metals, refers to the content of metal expressed as metallic element. 
     
     
         18 . The process according to  claim 17 , wherein the metal is in a quantity ranging from 0.3 to 1.5%. 
     
     
         19 . The process according to  claim 1  or  2 , wherein the hydrotreated light cycle oil is reacted with hydrogen in the presence of the catalytic system comprising:
 a) one or more metals selected from Pt, Pd, Ir, Ru, Rh and Re 
 b) a silico-aluminate of an acidic nature selected from a zeolite belonging to the MTW family and a completely amorphous microporous silico-alumina having an SiO 2 /AL 2 O 3  molar ratio ranging from 30 to 500, a surface area greater than 500 m 2 /g, a pore volume of between 0.3 and 1.3 ml/g, an average pore diameter smaller than 40 Å, at a temperature ranging from 240 to 380° C., at a pressure ranging from 10 to 100 atm, with a WHSV ranging from 0.5 to 5 hr −1  and a hydrogen and feedstock (H 2 /HC) ratio of between 400 and 2,000 Nlt/kg. 
 
     
     
         20 . The process according to  claim 19 , wherein the acidic component (b) is a MTW zeolite, the pressure is higher than 20 atm and lower than or equal to 80 atm, and the temperature ranges from 250 to 330° C. 
     
     
         21 . The process according to  claim 19 , wherein the acidic component (b) is a silico-alumina, the pressure is higher than 20 atm and lower than or equal to 80 atm, the temperature ranges from 300 to 380° C. 
     
     
         22 . The process according to  claim 1  or  2 , wherein the hydrotreatment is carried out at an LSHV space velocity ranging from 0.3 to 3 hr −1 . 
     
     
         23 . The process according to  claim 1  or  2 , wherein in the hydrotreatment step, a H Z /feedstock ratio ranging from 200 to 2,000 Nl/l, is used. 
     
     
         24 . A fluid catalytic cracking (FCC) process for the conversion of hydrocarbon cuts of an oil origin into blends containing Light Cycle Oil (LCO), carried out at a temperature ranging from 490 to 530° C. 
     
     
         25 . A fluid catalytic cracking (FCC) process for the conversion of hydrocarbon cuts of an oil origin into blends containing Light Cycle Oil (LCO), wherein the pre-heating temperature is within the range of 240 to 350° C. 
     
     
         26 . The fluid catalytic cracking (FCC) process according to  claim 24  or  25 , wherein the pre-heating temperature is within the range of 240 to 350° C. and the process is carried out at a temperature ranging from 490 to 530° C.