Application: To convert C9+ heavy aromatics, alone or in conjunction with toluene or benzene co-feed, primarily to mixed xylenes using ExxonMobil Chemical’s TransPlus process.
Description: Fresh feed, ranging from 100% C9+ aromatics to mixtures of C9+ aromatics with either toluene or benzene, are converted primarily to xylenes in the TransPlus process. Co-boiling C11 aromatics compo-nents, up to 435°F NBP, can be included in the C9+ feed. In this process, liquid feed along with hydrogen-rich recycle gas, are sent to the reactor (2) after being heated to reaction temperature through feed/effluent heat exchangers (3) and the charge heater (1).
Primary reactions occurring are the dealkylation of alkylaromatics, transalkylation and disproportionation, producing benzene/toluene and C8 aromatics. The thermodynamic equilibrium of the resulting product aromatics is mainly dependent on the ratio of methyl groups to aromat-ic rings in the reactor feed. Hydrogen-raromat-ich gas from the high-pressure separator (5) is recycled back to the reactor with makeup hydrogen (6).
Unconverted toluene and C9+ aromatics are recycled to extinction.
The ability of TransPlus to process feeds rich in C9+ aromatics en-hances the product slate toward xylenes. Owing to its unique catalyst, long cycle lengths are possible.
Economics: Favorable operating conditions, relative to other alternative technologies, will result in lower capital and operating costs for grass-roots units and higher throughput potential in retrofit applications.
Commercial plants: The first commercial unit was started up in Taiwan in 1997. There are 16 TransPlus references.
Licensor: ExxonMobil Chemical Technology Licensing LLC, (retrofit ap-plications)
Axens (grassroots applications) - CONTACT
BTX and C9+ product Offgas to fuel system
Toluene and C9+ recycle Fresh C9+ aromatics
Fresh toluene Makeup hydrogen
5 7 1
2
3 4
6
Petrochemical Processes 2010 2010
Petrochemical Processes Home Process Categories Company Index
Mixed xylenes
Application: To convert C9+ heavy aromatics, alone or in conjunction with toluene or benzene co-feed, primarily to mixed xylenes using Exx-onMobil Chemical’s TransPlus process.
Description: Fresh feed, ranging from 100% C9+ aromatics to mixtures of C9+ aromatics with either toluene or benzene, are converted primarily to xylenes in the TransPlus process. Co-boiling C11 aromatics components, up to 435°F NBP, can be included in the C9+ feed. In this process, liquid feed, along with hydrogen-rich recycle gas, are sent to the reactor (2) after being heated to reaction temperature through feed/effluent heat exchangers (3) and the charge heater (1).
Primary reactions occurring are the dealkylation of alkylaromatics, transalkylation and disproportionation, producing benzene/toluene and C8 aromatics containing over 95% xylenes. The thermodynamic equilibrium of the resulting product aromatics is mainly dependent on the ratio of methyl groups to aromatic rings in the reactor feed.
Hydrogen-rich gas from the high-pressure separator (5) is recycled back to the reactor with makeup hydrogen (6). Unconverted toluene and C9+ aromatics are recycled to extinction.
The ability of TransPlus to process feeds rich in C9+ aromatics enhances the product slate toward xylenes. Owing to its unique catalyst, long cycle lengths are possible.
Economics: Favorable operating conditions, relative to other alternative technologies, will result in lower capital and operating costs for grass-roots units and higher throughput potential in retrofit applications.
Commercial plants: The first commercial unit was started up in Taiwan in 1997. There are seven TransPlus units currently in operation.
Licensor: ExxonMobil Chemical Technology Licensing LLC, (retrofit ap-plications) - CONTACT
Axens (grassroots applications)
BTX and C9+ product Offgas to fuel system
Toluene and C9+ recycle Fresh C9+ aromatics
Fresh toluene Makeup hydrogen
5 7 1
2
3 4
6
Petrochemical Processes 2010 2010
Petrochemical Processes Home Process Categories Company Index
Copyright © 2010 Gulf Publishing Company. All rights reserved.
Mixed xylenes
Application: To selectively convert toluene to mixed xylene and high-pu-rity benzene using ExxonMobil Chemical’s Toluene DisProportionation 3rd Generation (MTDP-3) process.
Description: Dry toluene feed and up to 25 wt% C9 aromatics along with hydrogen-rich recycle gas are pumped through feed effluent heat exchangers and the charge heater into the MTDP-3 reactor (1). Toluene disproportionation occurs in the vapor phase to produce the mixed xy-lene and benzene product. Hydrogen-rich gas from the high-pressure separator (2) is recycled back to the reactor together with makeup hy-drogen. Unconverted toluene is recycled to extinction.
Reactor yields, wt%:
Toluene conversion, wt% 48
Operating conditions: MTDP-3 operates at high space velocity and low H2 / hydrocarbon mole ratio. These conditions could potentially result in increased throughput without reactor and/or compressor replacement in retrofit applications. The third-generation catalyst offers long operat-ing cycles and is regenerable.
Commercial plants: Four MTDP-3 licensees since 1995.
Reference: Oil & Gas Journal, Oct. 12, 1992, pp. 60 – 67.
Licensor: ExxonMobil Chemical Technology Licensing LLC (retrofit ap-plications) - CONTACT
Axens (grassroots applications)
Hydrogen recycle To fuel system
Product
Petrochemical Processes 2010 2010
Petrochemical Processes Home Process Categories Company Index
Mixed xylenes
Application: The Tatoray process produces mixed xylenes and petro-chemical grade benzene by disproportionation of toluene and transalk-lyation of toluene and C9+ aromatics.
Description: The Tatoray process consists of a fixed-bed reactor and product separation section. The fresh feed is combined with hydrogen-rich recycle gas, preheated in a combined feed exchanger (1) and heat-ed in a firheat-ed heater (2). The hot feheat-ed vapor goes to the reactor (3). The reactor effluent is cooled in a combined feed exchanger and sent to a product separator (4).
Hydrogen-rich gas is taken off the top of the separator, mixed with makeup hydrogen gas and recycled back to the reactor. Liquid from the bottom of the separator is sent to a stripper column (5). The stripper overhead gas is exported to the fuel gas system. The overhead liquid may be sent to a debutanizer column. The products from the bottom of the stripper are recycled back to the BT fractionation section of the aromatics complex.
With modern catalysts, the Tatoray process unit is capable of processing feedstocks ranging from 100 wt% toluene to 100 wt% A 9+. The optimal concentration of A 9+ in the feed is typically 40 – 60 wt%.
The Tatoray process provides an ideal way to produce additional mixed xylenes from toluene and heavy aromatics.
Economics: The process is designed to function at a high level of con-version per pass. High concon-version minimizes the size of the BT columns, and the size of Tatoray process unit, as well as the utility consumption of all of these units. Estimated ISBL costs based on a unit processing feed capacity of 1.92 million metric tpy (US Gulf Coast site in 2009):
Investment, US$ million 36
Utilities (per metric ton of feed)
Electricity, kWh 6.7
Water, cooling, m3 0.1
Fuel, MMkcal 1.19
Commercial plants: UOP has licensed a total of 54 Tatoray units; 46 of these units are in operation and 8 are in various stages of construction.
Licensor: UOP LLC, A Honeywell Company - CONTACT
Toulene and
Petrochemical Processes 2010 2010
Petrochemical Processes Home Process Categories Company Index
Copyright © 2010 Gulf Publishing Company. All rights reserved.
Mixed xylenes
Application: In a modern UOP aromatics complex, the TAC9 process is integrated into the flow scheme to selectively convert C9– C10 aromatics into xylenes rather than sending them to the gasoline pool or selling them as a solvent.
Description: The TAC9 process consists of a fixed-bed reactor and prod-uct separation section. The feed is combined with hydrogen-rich recycle gas, preheated in a combined feed exchanger (1) and heated in a fired heater (2). The hot feed vapor goes to a reactor (3). The reactor effluent is cooled in a combined feed exchanger and sent to a product separa-tor (4). Hydrogen-rich gas is taken off the top of the separasepara-tor, mixed with makeup hydrogen gas, and recycled back to the reactor. Liquid from the bottom of the separator is sent to a stripper column (5). The stripper overhead gas is exported to the fuel gas system. The overhead liquid may be sent to a debutanizer column or a stabilizer. The stabilized product is sent to the product fractionation section of the UOP aromat-ics complex.
Economics: The current generation of TAC9 catalyst has demonstrated the ability to operate for several years without regeneration. ISBL costs based on a unit processing 380,000 metric tpy of feed consisting of 100 wt% C9 – C10 (US Gulf Coast site in 2006):
Investment, US$ million 14
Utilities (per mt of feed)
Electricity, kWh 6.7
Water, cooling, m3 0.08
Fuel, MMkcal (credit) 1.2
Commercial plants: Three commercial units have been brought on-stream, with feed rates ranging from 210,000 metric tpy to 850,000 metric tpy.
Licensor: UOP LLC, A Honeywell Company - CONTACT
C9 aromatics feed
1 2
3
4 5
Makeup hydrogen
Purge gas
Product to fractionation
To fuel gas
Overhead liquid to debutanizer
Recycle gas