# US 10,308,571 B2 · Process for minimizing benzene, toluene, and a recycle loop in a zero benzene aromatics complex > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,308,571 B2 - Document ID: US10308571B2 - Status: Granted - Kind: B2 - Application number: 15/730,532 - Filed: 2017-10-11 - Published: 2019-04-11 - Granted: 2019-06-04 - Earliest claimed: 2017-10-11 - Assignees: Uop LLC - Applicants: Uop LLC - Inventors: Elizabeth A. Carter; Deng-Yang Jan; Timur V. Voskoboynikov - Web page: https://patentgrep.com/patent/US10308571B2 ## CPC - C07C 6/06: at a cyclic carbon-to-carbon double bond - C07C 2/66: Catalytic processes - C07C 2/864: {the non-hydrocarbon is an alcohol} - C07C 6/126: {of more than one hydrocarbon} - C07C 7/04: by distillation - C07C 2521/04: Alumina - C07C 2529/06: Crystalline aluminosilicate zeolites; Isomorphous compounds thereof - C07C 2529/70: of types characterised by their specific structure not provided for in groups C07C2529/08 - C07C2529/65 - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS ## Abstract The present invention relates to minimizing benzene, toluene, and an A9/A10 recycle loop in a zero benzene aromatics complex. More specifically, the present invention relates to a minimizing benzene, toluene, and an A9/A10 recycle loop in a zero benzene aromatics complex wherein the aromatic feed has a low methyl to phenyl ratio, and where the aromatic feed has a high methyl to phenyl ratio. ## Claims ### Claim 1 A process for reducing benzene in an aromatics complex, comprising: passing an aromatics stream having a methyl to phenyl ratio above 1.0 to a benzene column to produce a benzene column overhead stream comprising benzene and a benzene column bottoms stream comprising toluene and aromatics having 9+ carbons; passing the benzene column overhead stream to a trans-alkylation unit and transalkylating aromatics having 9+ carbons with benzene to produce a benzene trans-alkylation product stream; passing the benzene column bottoms stream to a toluene column to produce a toluene column overhead stream comprising toluene and a toluene column bottoms stream comprising aromatics having 9+ carbon; passing a first portion of the toluene column overhead stream to the trans-alkylation unit and transalkylating aromatics having 9+ carbons with toluene to produce a toluene transalkylation product stream; passing a second portion of the toluene column overhead stream to a toluene methylation unit to produce a toluene methylation unit product stream containing xylenes with para-xylene selectivity between 20% and 99.9% within the xylenes; passing the toluene column bottoms stream to a fractionation zone to produce an overhead stream comprising xylenes, a bottoms stream comprising heavy aromatics, and a middle boiling fraction comprising aromatics having 9-10 carbons; passing the middle boiling fraction from the fractionation zone to the trans-alkylation unit; recycling the benzene trans-alkylation product stream to the benzene column; and, recycling the toluene methylation unit product stream to the benzene column. ### Claim 2 (depends on 1) The process of claim 1, wherein the toluene methylation unit produces an effluent containing xylenes with para-xylene selectivity between 50% and 99.9% within the xylene fraction. ### Claim 3 (depends on 1) The process of claim 1, wherein the methyl to phenyl ratio of the aromatic stream is above 1.5. ### Claim 4 (depends on 1) The process of claim 1, wherein the methyl to phenyl ratio of the aromatic stream is above 1.8. ### Claim 5 (depends on 1) The process of claim 1, wherein the fractionation zone comprises a plurality of fractionation units. ### Claim 6 (depends on 1) The process of claim 1, wherein a portion of the toluene column overhead stream is sent directly to the trans-alkylation unit. ### Claim 7 (depends on 1) The process of claim 1, wherein a portion of the toluene column overhead stream is combined with the benzene column overhead stream before being sent to the trans-alkylation unit. ### Claim 8 (depends on 1) The process of claim 1, further comprising passing methanol or another alkylation agent to the toluene methylation unit. ### Claim 9 (depends on 1) The process of claim 1, further comprising sending a portion of the toluene column overhead to the benzene column overhead stream. ### Claim 10 (depends on 1) The process of claim 1, wherein toluene is allowed to pass to the overhead of the benzene column. ### Claim 11 (depends on 1) The process of claim 1, wherein the toluene methylation unit produces some product with methyl to phenyl ratio above 2. ### Claim 12 A process for reducing benzene in an aromatics complex, comprising: passing an aromatics stream having a methyl to phenyl ratio above 1.5 to a benzene column to produce a benzene column overhead stream comprising benzene and a benzene column bottoms stream comprising toluene and aromatics having 9+ carbons; passing the benzene column overhead stream to a trans-alkylation unit; passing the benzene column bottoms stream to a toluene column to produce a toluene column overhead stream comprising toluene and a toluene column bottoms stream comprising aromatics having 9+ carbon; passing a first portion of the toluene column overhead stream to the trans-alkylation unit; transalkylating aromatics having 9+ carbons with toluene from the first portion of the toluene column overhead stream and with benzene from the benzene column overhead stream to produce a transalkylation product stream; passing a second portion of the toluene column overhead stream to a toluene methylation unit to produce a toluene methylation unit product stream; passing the toluene column bottoms stream to a fractionation zone to produce an overhead stream comprising xylenes, a bottoms stream comprising heavy aromatics, and a middle boiling fraction comprising aromatics having 9-10 carbons; passing the middle boiling fraction from the fractionation zone to the trans-alkylation unit; recycling the benzene trans-alkylation product stream to the benzene column; and, recycling the toluene methylation unit product stream to the benzene column. ### Claim 13 (depends on 12) The process of claim 12, wherein the fractionation zone comprises a plurality of fractionation units. ### Claim 14 (depends on 12) The process of claim 12, wherein the toluene methylation unit produces an effluent containing xylenes with para-xylene selectivity between 20% and 99.9% within the xylenes. ### Claim 15 (depends on 12) The process of claim 12, wherein the toluene methylation unit produces an effluent containing xylenes with para-xylene selectivity between 50% and 99.9% within the xylenes. ### Claim 16 (depends on 12) The process of claim 12, wherein the portion of the toluene column overhead stream is sent directly to the trans-alkylation unit. ### Claim 17 (depends on 12) The process of claim 12, wherein the portion of the toluene column overhead stream is combined with the benzene column overhead stream before being sent to the trans-alkylation unit. ### Claim 18 (depends on 12) The process of claim 12, wherein the toluene methylation unit produces some product with methyl to phenyl ratio above 2.