Mobil/Badger cumene process

First commercialized at Georgia Gulfs Pasadena, TX plant in 1994, the Mobil-Badger Cumene process consists of a fixed-bed alkylator, a fixed-bed transalkylator and a separation section (22, 23). Fresh and recycle benzene are combined with liquid propylene in the alkylation reactor where the propylene is completely reacted. Recycled polyisopropylbenzenes are mixed with benzene and sent to the transalkylation unit to produce additional cumene. Trace impurities are removed in the depropanizer column. Byproduct streams consist of LPG (mainly propane contained in the propylene feedstock) and a small residue stream, which can be used as fuel oil. 

The use of zeolites in the manufacture of cumene is of immense importance. About 7 million metric tons of cumene are produced annually worldwide. The earlier-used process involved alkylation of benzene over a solid phosphoric acid or an aluminum chloride catalyst. Cumene Production, U.S. Patent 4008290. Both catalysts are toxic in nature. The Mobil/Badger cumene process (Mobil Technology Co., 1997) uses the less toxic carozine zeolite catalyst (see Fig. 3.7). In addition, it also generates less waste and requires less energy than the earlier catalysts, thus simultaneously satisfying various conditions of green chemistry. 

Two catalysts have emerged as commercially viable. The Mobil—Badger ethylbenzene process, which has been in commercial use since 1980, employs a ZeoHte catalyst and operates in the gas phase. A Hquid-phase ethylbenzene process joindy Hcensed by Lummus and UOP uses a Y-type ZeoHte catalyst developed by Unocal. This Hquid-phase process was commercialized in 1990. The same Y-type ZeoHte catalyst used for the production of ethylbenzene is being offered for the production of cumene but has not yet been commercialized. 

ABB Lummus Crest Inc. and Unocal Corp. have Hcensed a benzene alkylation process usiag a proprietary zeoHte catalyst. Unlike the Mobil-Badger process, the Unocal-Lummus process is suitable for either ethylbenzene or cumene manufacture (27,28). 

The reachon of benzene with ethylene or propylene to form ethylbenzene or isopropylbenzene (cumene) is an industrially important transformahon, with ethylbenzene as the key building block for polystyrene and cumene as the feedstock for phenol produchon [55]. Fthylbenzene was originally produced with a Lewis acid catalyst consishng of AlCfi or a Bronsted acidic solid phosphoric acid (SPA) catalyst [56]. Both catalyst systems suffered from equipment corrosion so, in the 1980s the Mobil-Badger vapor phase alkylation process was introduced, which... 

Over the past seven years, cumene producers have begun to convert to the more environmentally friendly and more efficient zeolite-based processes. Principal among these are processes licensed by Dow, CDTech, Mobil-Badger, Enichem, and UOP. The zeolite based processes produce higher cumene yields than the conventional SPA process because most of the diisopropylbenzene byproduct is converted to cumene in separate transalkylation processes. Operating and maintenance costs are reduced because there is no corrosion associated with the zeolite catalysts. Finally, environmental concerns associated with the disposal of... 

Application To produce cumene from benzene and any grade of propylene—including lower-quality refineiy propylene-propane mixture—using the Mobil/Badger process and a new generation of zeolite catalysts from ExxonMobil. 

Commercial plants The first commercial application of this process came onstream in 1996. At present, there are seven operating plants with a combined capacity exceeding 3 million mtpy. In addition, three revamped facilities and one grassroots plant with a combined capacity of over 1.5 million mtpy will be onstream by the year 2001. At that time, more than 50% of the worldwide cumene production will be from plants using the Mobil/Badger process. 

The Mobil/Badger vapor phase process includes four distillation columns. The first major separation is in a benzene recovery column where unconverted benzene is recovered as an overhead product for recycle to the alkylation and transalkylation reactors. The bottom stream is fed to an EB recovery column where EB product is separated from cumene, the PEB, and other heavy components. The cumene, PEB, and other heavy by-products are further separated in the PEB recovery column. The heavy residue is typically used as fuel in the reactor feed heater. The PEB fraction is recovered in the overhead stream and recycled to the transalkylation reactor where it reacts to form additional EB. A fourth column is used as a stabilizer column to vent any light components and to remove water from the system. 

Another method to remove benzene is to react it with propylene or ethylene (benzene alkylation) to produce propylbenzene (cumene) or ethylbenzene. Commercial benzene alkylation processes in the chemical industry have been known for many years. Typically these processes require fairly pure benzene and ethylene feed. The shape selective ZMS-5 catalyst is used as a basis for ethylbenzene synthesis in the Mobil-Badger process (Chen et. al, 1989). ZSM-5 is very selective in this process as a result this process is currently used in the chemical industry to produce about 25% of world s ethylbenzene. Currently there are 12 operating Mobil-Badger EB units including a recent Shell Chemical unit which uses FCC off-gas as the ethylene feedstock source. 

The aromatics alkylation with olefins is a well-known technology, especially in the case of ethylbenzene (a Mobil-Badger process [109]) and cumene production [110], Ethylbenzene synthesis can be catalyzed by diverse modified HZSM-5, BEA, rare-earth Y, and MCM-22 zeohtes. In most cases, the selectivity is pretty high (99%), but the process must be carried out at a large excess of benzene and the conversion of the latter typically does not exceed 20-25% at 400°C and WHSV= 3 h . For cumene production, a few commercial processes have been developed by CD-Tech (Y zeolite), Lummus-Unocal (Y zeolite), Enichem (H-BEA), Mobil-Raytheon (MCM-22), Dow Chemical (dealuminated mordenite (MOR)), and UOP (a Q-Max process with MgSAPO-31). 

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