Ethylbenzene production capacities

In the EBMax process, benzene is fed to the bottom of the liquid-filled multibed reactor. Ethylene is co-fed with the benzene and also between the catalyst beds. Polyethylbenzenes, which are almost exclusively diethylbenzenes, undergo transalkylation with benzene in a second reactor. Mobil-Badger offers both liquid phase and vapor phase transalkylation processes. The vapor phase process removes benzene feed coboilers such as cyclohexane and methylcyclopentane as well as propyl and butylbenzenes. Because the EBMax process produces very low levels of propyl and butylbenzenes, for most applications, the more energy efficient liquid phase process is preferred. Worldwide, there are currently ten licensed EBMax units with a cumulative ethylbenzene production capacity of five million metric tons per year. 

These processes account for over S5 per cent of world ethylbenzene production capacity. 

EBMax is a liquid phase ethylbenzene process that uses Mobil s proprietary MCM-22 zeolite as the catalyst. This process was first commercialized at the Chiba Styrene Monomer Co. in Chiba, Japan in 1995 (16-18). The MCM-22-based catalyst is very stable. Cycle lengths in excess of three years have been achieved commercially. The MCM-22 zeolite catalyst is more monoalkylate selective than large pore zeolites including zeolites beta and Y. This allows the process to use low feed ratios of benzene to ethylene. Typical benzene to ethylene ratios are in the range of 3 to 5. The lower benzene to ethylene ratios reduce the benzene circulation rate which, in turn, improves the efficiency and reduces the throughput of the benzene recovery column. Because the process operates with a reduced benzene circulation rate, plant capacity can be improved without adding distillation capacity. This is an important consideration, since distillation column capacity is a bottleneck in most ethylbenzene process units. The EBMax process operates at low temperatures, and therefore the level of xylenes in the ethylbenzene product is very low, typically less than 10 ppm. 

Styrene is at the centre of an important industry, with a value of some 66 billion euros. The styrene production capacity is ca. 20 Mt/a worldwide. Most is obtained by ethylbenzene dehydrogenation and all the production is used for the synthesis of polymers (polystyrene, styrene-acrylonitrile, styrene-butadiene) used as plastics and rubbers in the manufacture of household products packaging, tubes, tires, and endless other applications (see also Chapter 7). 

Ethylbenzene manufacture Economic data (France conditions, mid-1986) Production capacity 300,000 t/year... 

Shortly after the introduction of the Monsanto process, it was licensed by 15 other companies. The reactor built by Monsanto at its Texas City plant had a production capacity of 1.7 billion pounds of ethylbenzene per year. Yields of ethylbenzene based on both ethylene and benzene consumption are about 99%. 

There is no way to predict the effect of contaminants on reactor performance prolonged pilot plant trials are necessary. Contaminants may cause modifications in the selectivity of a reaction and reduce overall production capacity. For example, in the reduction of acetophenone to ethylbenzene, reaction selectivity was almost halved from its initial high value after only a few hours of operation, due to adsorption effects on the electrode surface. 

Worldwide capacities for the production of ethylbenzene in 1985 and 1995 are presented in Table 2. 

Fig. 1.12. Maximum temperature (a) and ethylbenzene conversion (b) during one production cycle for a fixed bed of uniform heat capacity (dotted line), fora structured fixed-bed with inert end sections of higher heat capacity (dashed line), and for latent heat storage inside the catalytic section (solid line) [9].

The most valuable isomer among the four C8 aromatics (ethylbenzene -EB-, para-xylene -pX-, ortho-xylene -oX- and meta-xylene -mX-) is pX, which is a chemical intermediate for the production of polyethyleneterephtalate (PET) fibers, resins and films. pX production is then driven by PET fiber and resin markets, which are growing at an estimated 4-6% per year for the next decade. The highest growth rates are observed in emerging countries, mainly in Asia, where most of the latest large capacity plants have been constructed. 

The worldwide capacity for ethylbenzene is currently estimated to be 23 million metric tons/year (1 metric ton = 1000 kg) with an annual growth rate projected to be approximately 4%. Over 90% of the world s production of ethylbenzene is used in the manufacture of styrene. Other applications include paint solvents and pharmaceuticals. 

A number of advantages of CD were obtained for the exothermic alkylation process and particularly noteworthy is the increased catalyst lifetime and enhanced selectivity to monoalkylated rather than dialkylated or trialkylated product. Catalytic Distillation Technology commercialized the production of ethylbenzene using the CD EB technology in 1994 at the Mitsubishi Petrochemical in Yokkaichi, Japan. The CD Cumene process was first brought onstream in 2000 at a capacity of 270,000 MTA by Formosa Chemicals and Fibre Corporation, Taiwan, and was expanded to double the capacity since 2004. 

Styrene is one of the most important monomers and extensively used in the production of plastics and synthetic rubbers, and 90% of the word styrene capacity is produced via the catalytic dehydrogenation of ethylbenzene. Several kinds of membrane reactors are investigated for this system and... 

Indirect oxidation of propylene is an important route for propylene oxide production that proceeds in two reaction steps. The first step is the formation of a peroxide from alkanes, aldehydes, or adds by oxidation with air or oxygen. The second reaction step is the epoxidation of propylene to PO by oxygen transfer from the peroxide with formation of water, alcohol, or acid. The catalytic oxidation of propylene with organic hydroperoxides is nowadays a successful commercial production route (51% of world capacity). Two organic hydroperoxides dominate the processes (i) a process using isobutane (peroxide tert-butyl hydroperoxide, co-product tert-butyl alcohol), which accounts for 15% of the world capacity and (ii) a process using ethylbenzene (peroxide ethylbenzene hydroperoxide, co-product styrene) that accounts for 33% of the world capacity. The process via isobutane is presented by ... 

The USA produced 1.6 million t xylenes [3] and 2 million t ethyl benzene/styrene [36] in 1970, and 2.9 million t xylenes and 3.8 million t ethylbenzene in 1978 [30 a]. The FRG produced 219,000 t xylenes [3] and some 300,000 t ethyl benzene/styrene [36] in 1970. For western Europe, production of these raw materials in 1980 is expected to be three times the 1970 figure [3]. In the USA in 1978, 0.5 million t o-xylene and 1.6 million t p-xylene were produced individually. The capacities in the European Community in 1980 were 0.6 million t o-xylene and 0.8 million t p-xylene [30 a]. Accordingly, world production of Cg-aromatics will probably amount to about 20 million t. However - as already mentioned - an additional 40 million t are consumed annually as a constituent of motor fuel. 

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