42 Aromatics Complex

Aromatics ComplexAromatics Aromatics Application An aromatics complex is a combination of process units which are used to convert naphtha, from a variety of sources, and pyrolysis gasoline into the basic petrochemical intermediates: benzene, toluene, and xylenes (BTX). Benzene is a building block for over 250 products, including ethyl benzene (for styrene), cumene (for phenol), and cyclohexane. Toluene has become increasingly valuable for the production of xylenes through toluene disproportionation and transalkylation with C9/C10 aromatics. If benzene is favored over toluene, a portion of the toluene produced can be used to make additional benzene through hydrodealkylation. The xylenes product contains four different C8 isomers: para-xylene, ortho-xylene, metaxylene, and ethyl benzene. The majority of the xylenes are processed further within the complex to produce one or more of the individual isomers. The isomer with the broadest commercial use is para-xylene, which is used almost exclusively for the production of polyester fibers, resins, and films. Ortho-xylene is used for the production of phthalic anhydride, typically used as a plasticizer. Meta-xylene is used for the production of iso-phthalic acid, which is gaining broader acceptance in PET resin blends. Production of meta-xylene is addressed separately in the MX Sorbex™ datasheet. Ethyl benzene is converted to benzene or xylenes within the aromatics complex. CCR Platforming™ Process - Selectively reforms naphtha to aromatics (BTX) and high purity hydrogen ED Sulfolane™ Process - Extracts benzene and toluene from the reformate using an extractive distillation flowscheme, (Liquid-Liquid Extraction can also be applied for certain feedstocks) Tatoray™ Process - Disproportionates toluene and transalkylates toluene with C9 /C10+ aromatics to benzene and xylenes UOP THDA Process - Thermal hydrodealkylation of toluene and heavier aromatics to benzene Parex™ Process - Separates high purity para-xylene from mixed C8 aromatics isomers Isomar™ Process - Re-establishes an equilibrium mixture of isomers via xylene isomerization and conversion of ethyl benzene to benzene or xylenes The choice between the THDA and Tatoray processes depends upon whether the principal product is benzene or para-xylene and their relative values. The incorporation of a Tatoray unit into the complex can more than double the yield of para-xylene from a given feedstock. THDA is considered when incremental benzene is preferred to increased xylenes production. THDA is usually the most costly source of benzene, relative to other production options, and for that reason is less commonly applied to a modern aromatics complex. Alternative configuration Another option would be to add an RZ PlatformingTM unit to the flow scheme to allow additional benzene/toluene production. The RZ Platforming unit would process a light naphtha cut to convert C6/C7 paraffins to benzene and toluene. There are a variety of flowschemes which could be considered such as recycling the nonaromatic ED Sulfolane raffinate back to the RZ Platforming unit to produce additional aromatics. See the RZ Platforming Tech Sheet for additional details Typical configuration The configuration of a complex depends upon the available feedstock, the desired product slate, and the amount of investment capital. A fully integrated modern complex designed to produce benzene, para-xylene, and ortho-xylene from naphtha typically contains the following UOP process technologies: UOP Naphtha Hydrotreating Process - Removes sulfur and nitrogen contaminants in the naphtha Process description The principal products from the aromatics complex illustrated in the flow diagram are benzene, para-xylene, and ortho-xylene. If desired, a fraction of the toluene, where the A9/A10 fraction is recovered and then recycled to the Tatoray or THDA unit. The C8+ material from the bottom of the toluene column is sent to the xylenes recovery section of the complex. If there is no Tatoray or THDA unit. This is the The effluent from the THDA unit is stripped to remove only unit in the complex that actually creates aromatic light ends and sent to the BT fractionation section. The aromatics extract is treated to remove trace olefins. The ED Sulfolane unit extracts the aromatics from the reformate splitter overhead and rejects an aromatics-free raffinate stream. and the overhead liquid is normally recycled back to the benzene column for recovery of residual benzene. NHT producing 104 -108 Research Octane Number (RONC) reformate. The C7. and then individual high-purity benzene and toluene products are recovered in the BT fractionation section of the complex. in order to maximize the production Naphtha of aromatics. which can be further refined into paraffinic solvents. This high severity operation also greatly reduces nonaromatic impurities in the C8 fraction of the reformate. If ortho-xylene is to be produced in the complex. then recycled to the BT fractionation section. The CCR Platforming unit is designed to run at very high severity. rings from nonaromatics. The naphtha is first hydrotreated to remove sulfur and nitrogen compounds and then sent to a CCR Alternatively. The CCR Platforming unit is also a significant provider of hydrogen makeup within the aromatics complex. some of the reformate may be used as a high-octane gasoline blending component rather than for petrochemicals production. the toluene and heavy aromatics can also Platforming unit. The CCR Platforming unit includes a debutanizer column. The other UOP Aromatics Complex units in the complex either separate the various aromatic components Raffinate into individual products or convert Sulfolane Hydrogen various aromatics species into Reformate Benzene higher-value aromatics products. or C9+ aromatics can be taken as products. The overhead gas is exported to the fuel gas system. Splitter Toluene Platforming Heavy Aromatics column. The C8+ fraction from the bottom of the reformate splitter is treated to reduce olefin content and then charged to a xylenes column at the front end of the xylenes recovery section. eliminating the need for extraction of the C8 aromatics. The reformate from the debutanizer column bottoms is sent to a reformate splitter column. and charged to the Tatoray unit for production of additional xylenes and benzene. The bottoms is sent to the Heavy Aromatics column.Aromatics Complex 2 mixed xylenes. and naphthenes are converted to aromatics. with the bulk of the hydrogen available for export from the complex to the refinery. The effluent from the Tatoray unit is sent to a stripper column within the Tatoray unit to remove light ends. with C7+ material flowing from the benzene column bottoms to the toluene column. Toluene from the toluene column overhead is usually blended with A9/A10 from the overhead of the THDA Bz Col Tol Col Heavy Aromatics Col Tatoray Heavy Aromatics para-Xylene Parex Isomar Light Ends Xylenes Splitter OX Column ortho-Xylene DeHept Column The overhead material from the Tatoray stripper or THDA stripper column is separated into gas and liquid products. The overhead from the xylenes column is sent to the Parex unit for recovery of para-xylene. which strips off the light ends from the reformate. paraffins be charged to a THDA unit for production of benzene. blended into gasoline or used as feedstock for an ethylene plant. Benzene is recovered as overheads from the benzene column. Also. The xylenes column bottoms . the xylenes column is designed to make a split between metaand ortho-xylene and drop a targeted amount of orthoxylene (OX) to the bottoms. the A9+ material is usually blended into gasoline or fuel oil. In the CCR Platforming unit.fraction from the overhead is sent to the ED Sulfolane unit for extraction of benzene and toluene. UOP has licensed more than 725 separate process units for aromatics production including over 238 CCR Platforming units. or benzene.700.000 to 1.000 MTA. which result in real economic benefit in the form of reduced operating and feedstock costs and increased capacity. Through close contact and continuous support from the time the plant is in its basic design and throughout its operating lifetime. These complexes range in size from 21. ortho-xylene. to a level of less than 1 wt-%. The overhead gas is exported to the fuel gas system and the overhead liquid is normally recycled back to the benzene column for recovery of residual benzene. Since the introduction of Parex in 1971 . As of 2006. 48 Tatoray units.Aromatics Complex 3 are then sent to an OX column where high purity orthoxylene product is recovered overhead. where 99.953 152 1.753 82 176 48/37/15 Overall Material Balance. vast design experience and operational experience. The effluent from the Isomar unit is sent to a deheptanizer column.UOP licensees benefit from our extensive database of operating plants. specific gravity IBP. MM US$ 290 (Inside battery limits only. The xylenes column overhead is sent directly to the Parex unit. m3/hr Fuel fired. The overhead from the deheptanizer is split into gas and liquid products. Maximum reliability and operability from experience .UOP transfers technology to our licensees primarily through our Estimated Erected Cost. The bottoms from the deheptanizer are recycled back to the xylenes column. The raffinate from the Parex unit is almost entirely depleted of paraxylene. provision of engineering and technical services. 2006 US Gulf Coast basis) Utility Consumption Electric power. Any residual toluene in the extract is fractionated out in the finishing column within the Parex unit. The bottoms of the OX column are then sent to the Heavy Aromatics column. In this way. 88 Parex units. Continued R&D investment in technology . Ethyl benzene in the Parex unit raffinate is either converted to additional xylenes or dealkylated to benzene. all the C8 aromatics are continually recycled within the xylenes recovery section of the complex until they exit the aromatics complex as paraxylene. and 38 THDA units. Superior technology transfer and support . MMkcal/hr* * credit not taken for heating value of light ends 26. The Parex raffinate is sent to the Isomar unit. result in the economic optimization of our designs. Case study Feed Basis: Mid East Naphtha Heartcut Product objectives: Maximize para-xylene production Naphtha Feedstock Properties Feed.New catalysts. 147 Sulfolane units. our licensees are able to understand how to apply the technology to their plant and keep it running safely and reliably. °C P/N/A (wt-%) 0. where additional para-xylene is produced by re-establishing an equilibrium distribution of xylene isomers. UOP has designed 88 integrated aromatics complexes which produce both benzene and para-xylene. °C EP. Recent developments have enabled capital cost reductions of more than 15% from the previous generation aromatics complex design. 89 extraction units using other technology (UdexTM/Carom). adsorbents and process improvements are continuously being developed by UOP.479 54 Medium pressure steam. Licensees can benefit from these developments to keep their plants on the forefront of technology improvements. MT/hr Commercial experience UOP is the world’s leading licensor of process technology for aromatics production. depending upon the type of Isomar catalyst used. kW Cooling water. and then recycled to the Tatoray or THDA unit. which allows licensees to reliably operate the technology under a wide range of economic conditions. 68 Isomar units.The combination of UOP’s engineering practices. KMTA Feed naphtha Products Benzene Para-xylene Ortho-xylene Heavies Sulfolane raffinate Pure hydrogen LPG Light ends 238 700 100 9 174 40 22 252 1535 1535 Features and benefits Lowest investment and operating cost . which allows our licensees to build plants with the lowest investment and operating costs.9 wt-% pure para-xylene is recovered by adsorptive separation at 97 wt-% recovery per pass. uop. www.A.com © 2006 UOP LLC. and revamping individual units for higher capacity. improved product qualities. UOP undertakes several major aromatics complex revamp projects every year. contact your local UOP representative or our Des Plaines sales office: e-mail: info@uop. In addition to licensing new facilities. These projects cover a broad range of possibilities. or improved energy efficiency. All rights reserved. For more information Aromatics technology services are available upon request. such as the addition of toluene disproportionation or para-xylene recovery sections into existing complexes. The information in this document should not be construed as a representation for which UOP assumes legal responsibility.com fax: +1-847-391-2253 phone: +1-847-391-2000 UOP LLC 25 East Algonquin Road Des Plaines. For more information. UOP also has extensive experience revamping existing aromatics complexes to achieve higher capacity or better operating efficiency. UOP 4680-1 1106AR0S . installing parallel process unit trains.S. or an authorization or recommendation to practice a patented invention without a license. IL 60017-5017 U. debottlenecking projects.Aromatics Complex 4 UOP has been selected for 90% of the para-xylene capacity built.