# US 7,612,246 B2 · Process for isomerization of a C7 fraction with co-production of an aromatic molecule-rich fraction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,612,246 B2 - Document ID: US7612246B2 - Status: Granted - Kind: B2 - Application number: 11/232,108 - Filed: 2005-09-22 - Published: 2006-05-18 - Granted: 2009-11-03 - Earliest claimed: 2004-09-22 - Assignees: Institut Francais du Petrole - Inventors: Paul Broutin; Dominique Casanave; Jean-Francois Joly; Elsa Jolimaitre - Web page: https://patentgrep.com/patent/US7612246B2 ## CPC - C10L 1/06: for spark ignition - C10G 2400/30: Aromatics - C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS - C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES ## Abstract Process for the production of a RON isomerate that is at least equal to 80 and that contains less than 1% by weight of aromatic compounds and for co-production of an aromatic fraction that for the most part contains toluene, starting from a fraction with 7 carbon atoms containing paraffins, aromatic compounds and naphthenes. ## Claims ### Claim 1 A process for the production of a RON isomerate that is at least equal to 80 and for co-production of an aromatic fraction that for the most part contains toluene, staffing from a C7 fraction containing paraffins, naphthenes and aromatic compounds in any proportion, whereby said process employs at least one step comprising passing fresh feedstock (11) into an extractive distillation unit for extracting aromatic compounds (EA) so as to produce an aromatic fraction (23) containing mostly toluene, and a dearomatized C7 fraction (12) that is introduced into a distillation column (CD) from which are extracted: a) A top flow (13) that constitutes an isomerate produced in isomerization unit (IS), b) A lateral flow (14) that feeds isomerization unit (IS), c) A bottom flow (15), at least in part feeds a unit for opening naphthene rings (OC) from which is extracted an effluent (16) that is sent at least in part to isomerization unit (IS), within said isomerization unit (IS), conducting at least one step of isomerization of linear paraffins and mono-branched paraffins into multi-branched paraffins wherein the resultant isomerate contains less than 1% by weight of aromatic compounds, and at least one step of separating resultant stream of linear and mono-branched paraffins from di- and tri-branched paraffins. ### Claim 2 (depends on 1) A process according to claim 1, further comprising an effluent (16) from the naphthene ring opening unit (OC) in part to feed column (CD) and mixed with flow (12). ### Claim 3 (depends on 1) A process according to claim 1, wherein the top flow (13) of distillation column (CD) is sent into a unit (SP) for separating normal and mono-branched paraffins, on the one hand, and di- and tri-branched paraffins, on the other hand, and reintroducing resultant normal and mono-branched paraffins (21) into isomerization unit (IS), and wherein the di- and tri-branched paraffins (20) constitute the isomerate having an RON greater than 80. ### Claim 4 (depends on 1) A process according to claim 1, wherein distillation column (CD) is of the column type with an internal wall. ### Claim 5 (depends on 3) A process according to claim 3, wherein the separation of the linear and mono-branched paraffins, on the one hand, and di- and tri-branched paraffins, on the other hand, is conducted by pressure swing adsorption (PSA). ### Claim 6 (depends on 3) A process according to claim 3, wherein the separation of the linear and mono-branched paraffins, on the one hand, and di- and tri-branched paraffins, on the other hand, conducted by simulated countercurrent adsorption (CCS). ### Claim 7 (depends on 1) A process according to claim 1, further comprising a preceding step, wherein the C7 feedstock is introduced into a unit for specific dehydrogenation of naphthenes, upstream from the unit for extracting aromatic compounds. ### Claim 8 (depends on 1) A process according to claim 1, wherein the resultant isomerate contains less than 0.5% by weight of aromatic compounds. ### Claim 9 (depends on 1) A process according to claim 1, wherein effluent (17) from the isomerization is subjected to stabilization in a column so as to remove gases at the top of the column and to obtain a stabilized flow (18) at the bottom of the column which has a composition similar to that of effluent (17). ### Claim 10 (depends on 1) A process according to claim 1, further comprising recycling the linear and mono-branched paraffins from said step of separating to the inlet of the isomerization unit (15) and mixed with said dearomatized effluent. ### Claim 11 (depends on 1) A process according to claim 1, further comprising after optional stabilization, effluent from the isomerization unit is recycled to distillation column (CD) at a level that is located above the feed level of the column. ### Claim 12 (depends on 1) A process according to claim 1, further comprising after any stabilization, effluent from the isomerization unit is recycled to distillation column (CD) at a level that is located above the outlet level of lateral flow (14). ### Claim 13 (depends on 1) A process according to claim 1, further comprising effluent (18) from the isomerization unit is subjected to stabilization and then recycled to distillation column (CD) at a level that is located above the outlet level of lateral flow (14). ### Claim 14 (depends on 1) A process according to claim 1, wherein the aromatic fraction contains above 97% toluene. ### Claim 15 (depends on 3) A process according to claim 3, wherein the aromatic fraction contains above 97% toluene.