Fischer-Tropsch synthesis in supercritical fluids. Final report

Akgerman, Aydin; Bukur, D.B.

doi:10.2172/569022

Cited by 1 publication

(2 citation statements)

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“…These results also show that the operational upset at the beginning of the test did not have an effect on olefin selectivities during the early periods of SFTS in run FA-1724. Similar olefin selectivities were also obtained in run FA-1075 (total pressure of 5.5 MPa; syngas partial pressure of ∼1.5 MPa) conducted in our laboratory (Akgerman and Bukur, 1995), under the same baseline conditions as employed in run FA-1724. This represents an additional evidence that selectivities in periods 2-4 in run FA-1724 were not affected by the operational upset described above.…”

Section: Resultssupporting

confidence: 71%

“…We did not attempt to estimate a value of the reaction rate constant for the R-olefin readsorption reaction and hence cannot quantify the intraparticle diffusional resistance for this reaction. However, we have determined experimentally molecular diffusivities of C 8 hydrocarbons in both Fischer-Tropsch hydrocarbon wax (Rodden, 1988;Erkey et al, 1990) and supercritical propane (Akgerman and Bukur, 1996) utilizing the Taylor dispersion method. Molecular diffusivity of n-octane (C 8 H 18 ) in hydrocarbon wax at 250 °C and 1.48 MPa (the same conditions as in run FB-1644) was 5.6 × 10 -9 m 2 /s, whereas in supercritical propane at 250 °C and 6.2 MPa (similar to reaction conditions used in run FA-1724) the molecular diffusivity of 1-octene was 8.7 × 10 -8 m 2 /s.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Process Conditions on Olefin Selectivity during Conventional and Supercritical Fischer−Tropsch Synthesis

Bukur

Lang

Akgerman

et al. 1997

Ind. Eng. Chem. Res.

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A precipitated iron catalyst (100 Fe/5 Cu/4.2 K/25 SiO2 on mass basis) was tested in a fixed-bed reactor under a variety of process conditions during conventional Fischer−Tropsch synthesis (FTS) and supercritical Fischer−Tropsch synthesis (SFTS). In both modes of operation it was found that: total olefin content decreases whereas 2-olefin content increases with either increase in conversion or H2/CO molar feed ratio. Total olefin and 2-olefin selectivities were essentially independent of reaction temperature. The effect of conversion was more pronounced during conventional FTS. Comparison of olefin selectivities in the two modes of operation reveals that total olefin content is greater while the 2-olefin content is smaller during SFTS. Also, both the decrease in total olefin content and the increase in 2-olefin content with increase in carbon number (i.e. molecular weight of hydrocarbon products) was significantly less pronounced during SFTS in comparison to the conventional FTS. The obtained results suggest that 1-olefins, and to a smaller extent n-paraffins, are the primary products of FTS. Secondary reactions (isomerization, hydrogenation, and readsorption) of high molecular weight α-olefins occur to a smaller extent during SFTS, due to higher diffusivities and desorption rates of α-olefins in the supercritical propane than in the liquid-filled catalyst pores (conventional FTS).

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Section: Resultssupporting

confidence: 71%