Table V, which appeared on p. 3115, appears below in its corrected form. Reference 4, appearing on page 3126, should read as follows: 4. Imhoff, D. W.; Simeral, L. S.; Blevis, D. R.; Beard, W. R. ACS Symposium Series 2000, 749, 177.
The theoretial and experimental basis for obtaining infrared emission and specular reflection spectra of molten salts in general, and particularly of chloroaluminates, has been described. New quantities, ε* and r*, which use a thick (opaque) melt as the reference, give excellent representations of the absorption bands. This method eliminates band splitting due to variations in surface reflectivity or as a result of a cold surface layer of the sample. From the recorded spectra it has been concluded that acts as a tridentate ligand towards Mg2+, but as a bidentate ligand towards Zn2+. From the direct observation of anion-cation vibrations it has been shown that the interaction increases in the series Cs+
The ratio between propene and propane (C3 o/p) during Fischer–Tropsch synthesis (FTS) has been analyzed based on both literature reports and experiments for five catalysts. The latter comprise four cobalt catalysts on γ-alumina with variations in pore sizes, and one catalyst on α-alumina. Overall variations include H2/CO feed ratio, residence time, water addition, transients between test conditions, CO conversion, cobalt particle size, promoter (Re), and support material. It was possible to rationalize all data based on secondary hydrogenation of olefins. In fact, it was deduced that olefins are dominating termination products in FTS, estimated to ca. 90% for C3, but that some paraffins most likely are also produced directly. Increased residence time and high H2/CO feed ratio favors olefin hydrogenation, while added water presumably displaces hydrogen on cobalt giving enhanced C3 o/p. High cobalt dispersion favors hydrogenation, as also promoted by Re. Effect of intraparticle diffusion is seen in transient periods; for example, as water is added or depleted. There is frequently positive correlation between C3 o/p and selectivity to longer chains; the latter expressed as C5+ selectivity, as both are sensitive to hydrogen activity. Some modifications, however, are needed due to the accepted volcano plot for C5+ selectivity with cobalt crystallite size. Titania as support shows unexpectedly low C3 o/p; probably due to SMSI (strong-metal-support-interaction).
Optimization of once-through three-stage Fischer-Tropsch (FT) synthesis using path optimization is performed in this study to identify optimal structure and strategies in multi-stage FT synthesis design. The study also compares three-stage designs against recycled single-stage and two-stage designs with identical residence time and outlines key differences between different plant configurations. The results showed that it is optimal to operate at the maximum possible CO conversion and as low H2/CO ratio as possible. The comparison of the once-through three-stage and recycled two-stage processes against recycled single-stage process showed that two-stage and three-stage processes can achieve 2.3 % and 2.7 % higher syncrude production and 2.8 % and 3.2 % higher net material value (objective function). With the possibility of recycling in all three designs, the multi-stage processes improve further: 4.2 % and 5.3 % better in terms of syncrude production and 4.2 % and 6 % better in terms of the net material value.
