Method for converting a heavy load using a catalytic cracking unit and a step for selective hydrogenation of gasoline from catalytic cracking

• Main Authors: TOUCHAIS, NATACHA, PUCCI, ANNICK, FEUGNET, FREDERIC, HUGUES, FRANCOIS, DULOT, HUGUES
• Format: Patent
• Language: English; French; German
• Published: 11.09.2013
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; CRACKING HYDROCARBON OILS; FUELS; LUBRICANTS; METALLURGY; MINERAL WAXES; ORGANIC CHEMISTRY; PEAT; PETROLEUM, GAS OR COKE INDUSTRIES; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVEHYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, ORGASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; TECHNICAL GASES CONTAINING CARBON MONOXIDE

The method comprises (a) catalytic cracking (FCC) of a heavy cut producing a cut petrol C5-220[deg] C when the FCC is directed towards the production of petrol and C5-150[deg] C when the FCC is directed towards the production of average distillate, (b) performing selective hydrogenation of the cut petrol output from a catalytic cracking unit (2), (c) separating the petrol output from of the step (b) by distillation to separate two cuts including a cut light petrol C5-pF and a cut heavy petrol pF-220[deg] C, and (d) purifying light petrol C5-pF output to reduce nitrogen to less than 0.2 ppm. The method comprises (a) catalytic cracking (FCC) of a heavy cut producing a cut petrol C5-220[deg] C when the FCC is directed towards the production of petrol and C5-150[deg] C when the FCC is directed towards the production of average distillate, (b) performing selective hydrogenation of the cut petrol output from a catalytic cracking unit (2) functioning at a pressure of 0.5-5 MPa, a temperature of 80-220[deg] C and liquid hourly space velocity (LHSV) of 1-10 hours -> 1>, where the LHSV is expressed in liters of load per liter of catalyst per hour, (c) separating the petrol output from of the step (b) by distillation to separate two cuts including a cut light petrol C5-pF and a cut heavy petrol pF-220[deg] C, where the temperature pF is a boundary between light petrol and heavy petrol and in a range of 50-80[deg] C, (d) purifying light petrol C5-pF output from of the step (c) to reduce nitrogen to less than 0.2 ppm, (e) performing oligomerization of light petrol C5-pF output from the step (d), and (f) separating oligomers obtained at the step (e) to release two cuts including a cut petrol C5-150[deg] C and a cut distillate 150[deg] C+. The operating conditions of the step (e) are: temperature of 120-250[deg] C; pressure of 3-6 MPa; and catalysts based on sulfonic resin type when the method functions in maximum mode propylene. The cut petrol C5-150[deg] C and the cut distillate 150[deg] C+ output from of the step (f) are recycled with the FCC when the method functions in the maximum mode propylene. The cut distillate 150[deg] C-360[deg] C output from the step (f) after the step (e) is recycled in the FCC to improve aggregate output of petrol such as selectivity of petrol compared to the average distillate when the method functions in a maximum mode petrol. The operating conditions of the step (e) are: temperature of 150-350[deg] C; pressure of 3-6 MPa; and catalyst based on silica-alumina or amorphous aluminosilicate or crystalline zeolite when the method functions in a maximum mode distillate. The cut light petrol PI-150[deg] C is recycled with the FCC when the method functions in the maximum mode distillate. The step (d) located upstream of the step (e) is removed when the nitrogen content of the light petrol output from of the step (c) is lower than 1 ppm. A purification unit (15) located upstream unit of an oligomerization unit (17) uses a prior wash with water followed by adsorption onto adsorbents. La présente invention décrit un procédé de conversion d'une charge lourde présentant une flexibilité pour la production de propylène, d'essence et de distillat moyen. Le procédé fait appel à une unité de craquage catalytique et une unité d'oligomérisation des oléfines en C4 à C9. Le procédé selon l'invention inclut une hydrogénation sélective de la coupe essence brute issue de l'unité de craquage catalytique, et une séparation entre une coupe essence légère et une coupe essence lourde, l'essence légère étant dirigée vers l'unité d'oligomérisation.