Motor fuels polymerization units

Processes for the polymerization of hydrocarbon gases to motor fuel were developed to a commercial level in the early 1930 s. Thermal polymerization plants, employing temperatures of 900° to 1200° F. and pressures of 60 to 3000 pounds per square inch, were developed first, closely followed by catalytic units operating at temperatures of 280° to 475° F. and pressures of 200 to T 200 pounds per square inch. Currently, thermal polymerization finds its greatest application in combination with thermal reforming of naphtha. Catalytic polymerization has proved highly successful, as is indicated by the fact that one company alone has licensed over 150 plants to date. 

Polymerization of olefins from cracked gases today covers a broad range of products from motor fuel to petrochemicals. The petrochemical list is expanding rapidly with many of these products being made from propylene. Figure 1 shows a typical chamber type unit for producing the important petrochemicals, tetramer and cumene. 

With the increased use of catalytic cracking, large quantities of fight olefins become available. Utilization of these reactive, cheap streams for gasoline production became the object of much petroleum research. One of the processes arising out of this work was the catalytic poljnnerization of Cs and C4 olefins to gasoline. The first unit for polymerization of olefins to motor fuel went on stream in 1935. A year before, the cold-acid process for isobutylene dimerization was announced. This was followed shortly by the hot-acid process for copolymerization of all C4 olefins. 

Metal cyclopentadienyls have already proved to be of considerable technical interest. According to investigations carried out mainly in the United States, ferrocene is able to bring about smokeless combustion of fuel oil when added in amounts of 0.05% (1). Its use as an oil additive for jet motors and as an antiknock has also been proposed. Liquid ferrocene is said to have advantages as a thermally stable heat-transfer medium. Dicyclopentadienyl nickel also has possible applications, and dicyclopentadienyl titanium-dichloride has been studied in association with aluminum alkyls for the polymerization of ethylene (15, 133, 134). Finally, the carbonyl CHsC5H4Mn(CO)3 has been considered as a fuel additive in conjunction with tetraethyl lead (0). Other information is given in the patent literature (40). 

---