Effect of Oxygenates on the Oligomerization of Fischer−Tropsch Olefins over Amorphous Silica−Alumina

Abstract

The oligomerization of Fischer-Tropsch derived olefins over amorphous silica-alumina (ASA) has been investigated with feed materials containing 1-4% oxygenates to determine the effect of the oxygenates on catalyst performance and transportation fuel quality. The main differences between the oligomerization of oxygenate-containing and oxygenate-free olefinic feeds were: (a) higher deposition rate of carbonaceous material on the catalyst due to the carbonyls in the feed being converted to aromatic coke precursors; (b) shorter cycle length, although cycle lengths up to 8 months could be achieved with careful operation; and (c) formation of carboxylic acids from the carbonyls in the feed. Reaction over alumina and water washing were evaluated as feed pretreatment steps to reduce the oxygenate content in the feed, but neither were able to completely remove the carbonyls. All tests were done at pilot plant scale in the operating range 110-300 °C and 6 MPa.

Inhibiting effect of decanoic acid and its by-products on the transformation of n-hexadecane over a Pt/SiO2-Al2O3 catalyst

“…Studies about the reactivity and impact of these oxygenated compounds on hydrocracking catalysts are scarce and this point can be of crucial importance, as both the activity and selectivity of the catalysts towards liquid fuels can be affected. In the literature, few authors showed that alcohols, acids and oxygenated compounds can interact with acid sites [16][17][18][19][20][21]. In this case, the acidic function of hydrocracking catalysts can be impacted by the presence of oxygenates.…”

Kinetic model for the dimerisation of 1-hexene over a solid phosphoric acid catalyst

“…This involves the use of a solid acid catalyst and in industry mainly ZSM-5 and solid phosphoric acid (SPA) are used [1] and [2]. Industrially, the oligomerisation of shorter chain olefins is more established in the production of petrol [3].…”

Catalysis in the Upgrading of Fischer–Tropsch Syncrude

“…121,122 The distillate thus produced has a higher density (810 kg m À3 ; much needed in FT refining) than any of the other OLI catalysts. The hydrogenated distillate also has good cold flow properties, but with a cetane number of only 28-30.…”

“…122 Oncethrough operation with C 7 -C 10 feed resulted in a distillate yield of 53-60%. When the motor gasoline fraction from the OLI of C 7 -C 10 feed was recycled, the distillate yield increased to 63-67%.…”