Ethylene production dehydrogenation

Production of maleic anhydride by oxidation of / -butane represents one of butane s largest markets. Butane and LPG are also used as feedstocks for ethylene production by thermal cracking. A relatively new use for butane of growing importance is isomerization to isobutane, followed by dehydrogenation to isobutylene for use in MTBE synthesis. Smaller chemical uses include production of acetic acid and by-products. Methyl ethyl ketone (MEK) is the principal by-product, though small amounts of formic, propionic, and butyric acid are also produced. / -Butane is also used as a solvent in Hquid—Hquid extraction of heavy oils in a deasphalting process. 

Butadiene is obtained mainly as a coproduct with other light olefins from steam cracking units for ethylene production. Other sources of butadiene are the catalytic dehydrogenation of butanes and butenes, and dehydration of 1,4-butanediol. Butadiene is a colorless gas with a mild aromatic odor. Its specific gravity is 0.6211 at 20°C and its boiling temperature is -4.4°C. The U.S. production of butadiene reached 4.1 billion pounds in 1997 and it was the 36th highest-volume chemical. ... 

The ideal feed for ethylene production is ethane, which can give the highest ultimate yield via dehydrogenation. Ethylene selectivities of 85-90% can be achieved at temperatures above 800°C and a steam ethane ratio of about 0.3. 

Section, which appears every month. It also has a special section on Patents which lists new patents according to their classification. The Process Issue of the Petroleum Refiner is now carrying a special section on Petrochemical Processes. In the September 1952 issue for example, Extractive Distillation for Aromatic Recovery, Modified SO2 Extraction for Aromatic Recovery, Udex Extraction, Ethylene Manufacture by Cracking, Ethylene Production, Hypersorption, Hydrocol, Dehydrogenation (for butadiene), and Butadiene Process, were described. These descriptions include the main essentials of the process, simplified flow diagrams, and the name of the company offering it. Formerly these processes were described under the Process Section. 

Similarly, ethane can also be converted into ethylene in a PCMR with enhanced ethylene yields (Shi et al., 2008). Electrical power can be co-gen-erated with ethylene product in fuel cell operation mode (Fig. 8.8b). The performance of the fuel cell MR can be improved by reducing the membrane thickness, because of the increased permeation property (Fu et al., 2010). Some results from the literature on propane/ethane dehydrogenation in PCMRs have been summarized in Table 8.5. 

Butadiene. Global consumption of butadiene monomer in 1996 was 7.5 million metric tons (1). The largest use of butadiene was for styrene-butadiene rubber, representing 28% of the total volume. Butadiene is manufactured in several different ways. The key industrial processes include recovery of butadiene from ethylene production as a by-product and dehydrogenation using either the... 

Butadiene is made commercially by dehydrogenating butanes or butenes in the presence of a catalyst, by reacting ethanol and acetaldehyde, and by the cracking of naphtha and light oil. It is also derived as a by-product in ethylene production. 

Rodriguez, M., Ardissone, D., Lopez, E.,etaJ.(20U). Reactor Designs for Ethylene Production via Ethane Oxidative Dehydrogenation Comparison of Performance, Ind. Eng. Chem. Res., 50, pp. 2690-2697. 

Acidic Ni-Y zeolite exhibits an ethylene productivity up to l.OSgCC H ) g(Cat)" h with a selectivity of 75%. Acidic Cu- and Fe-Y zeolites are somewhat inferior with the ethylene productivity of 0.37 gCC H ) g(Cat) h" and a selectivity of 50%. Surprisingly, the authors concluded that the acidity of the zeolite favors both oxidative dehydrogenation of ethane (ODHE) productivity and ethylene selectivity. 

Rodriguez, M. A. L., Ardissone, D. E., L6pez, E., Pedemera, M. N. and Borio, D. O. (2010) Reactor designs for ethylene production via ethane oxidative dehydrogenation comparison of performance. Industrial and Engineering Chemistry Research, 50,2690-2697. 

In a widely used industnal process the mixture of ethylene and propene that is obtained by dehydrogenation of natural gas is passed into concentrated sulfunc acid Water is added and the solution IS heated to hydrolyze the alkyl hydrogen sulfate The product is almost exclusively a sin gle alcohol Is this alcohol ethanol 1 propanol or 2 propanoH Why is this particular one formed almost exclusively" ... 

Beginning in the middle of the twentieth century alternative methods of acetylene production became practical One of these is based on the dehydrogenation of ethylene... 

Acetaldehyde, first used extensively during World War I as a starting material for making acetone [67-64-1] from acetic acid [64-19-7] is currendy an important intermediate in the production of acetic acid, acetic anhydride [108-24-7] ethyl acetate [141-78-6] peracetic acid [79-21 -0] pentaerythritol [115-77-5] chloral [302-17-0], glyoxal [107-22-2], aLkylamines, and pyridines. Commercial processes for acetaldehyde production include the oxidation or dehydrogenation of ethanol, the addition of water to acetylene, the partial oxidation of hydrocarbons, and the direct oxidation of ethylene [74-85-1]. In 1989, it was estimated that 28 companies having more than 98% of the wodd s 2.5 megaton per year plant capacity used the Wacker-Hoechst processes for the direct oxidation of ethylene. 

Vinyltoluene. Viayltoluene is produced by Dow Chemical Company and is used as a resia modifier ia unsaturated polyester resias. Its manufacture is similar to that of styrene toluene is alkylated with ethylene, and the resulting ethyltoluene is dehydrogenated to yield vinyltoluene. Annual production is ia the range of 18,000—23,000 t/yr requiring 20,000—25,000 t (6-7.5 x 10 gal) of toluene. 

Benzene is alkylated with ethylene to produce ethylbenzene, which is then dehydrogenated to styrene, the most important chemical iatermediate derived from benzene. Styrene is a raw material for the production of polystyrene and styrene copolymers such as ABS and SAN. Ethylbenzene accounted for nearly 52% of benzene consumption ia 1988. 

The pattern of commercial production of 1,3-butadiene parallels the overall development of the petrochemical industry. Since its discovery via pyrolysis of various organic materials, butadiene has been manufactured from acetylene as weU as ethanol, both via butanediols (1,3- and 1,4-) as intermediates (see Acetylene-DERIVED chemicals). On a global basis, the importance of these processes has decreased substantially because of the increasing production of butadiene from petroleum sources. China and India stiU convert ethanol to butadiene using the two-step process while Poland and the former USSR use a one-step process (229,230). In the past butadiene also was produced by the dehydrogenation of / -butane and oxydehydrogenation of / -butenes. However, butadiene is now primarily produced as a by-product in the steam cracking of hydrocarbon streams to produce ethylene. Except under market dislocation situations, butadiene is almost exclusively manufactured by this process in the United States, Western Europe, and Japan. 

Although ethylene is produced by various methods as follows, only a few are commercially proven thermal cracking of hydrocarbons, catalytic pyrolysis, membrane dehydrogenation of ethane, oxydehydrogenation of ethane, oxidative coupling of methane, methanol to ethylene, dehydration of ethanol, ethylene from coal, disproportionation of propylene, and ethylene as a by-product. 

The generation of caibocations from these sources is well documented (see Section 5.4). The reaction of aromatics with alkenes in the presence of Lewis acid catalysts is the basis for the industrial production of many alkylated aromatic compounds. Styrene, for example, is prepared by dehydrogenation of ethylbenzene made from benzene and ethylene. 

---