| 1. |
- Andersson, Sven-Ingvar, 1943, et al.
(författare)
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Discrepancies in FCC Catalyst Evaluation of Atmospheric Residues
- 2007
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Ingår i: Studies in Surface Science and Catalysis. - 0167-2991. - 0444530606 ; 166, s. 13-29
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Tidskriftsartikel (refereegranskat)abstract
- Processing of atmospheric residues in fluid catalytic crackers (FCC) is a field of considerable interest today. When this application was new, around 1984, Statoil initiated a test program related to fluid catalytic cracking of North Sea atmospheric residues. Within this program catalysts and feeds are tested in a Micro Activity Test (MAT) reactor at Statoil and in a circulating Arco Pilot Unit at Chalmers.The catalysts are tested with the same atmospheric residue feed that is used in the commercial FCC unit at the Statoil Mongstad refinery in Norway. This is essential because erroneous ranking of the catalysts might otherwise occur. The equilibrium catalyst in a commercial residue FCC unit has normally high metals content. This is simulated by testing the catalysts impregnated by nickel and vanadium and deactivated by the cyclic propene steaming (CPS) method.New catalysts are tested together with a reference catalyst in both the MAT and Pilot Unit reactors. Usually the catalysts show the same ranking in both the MAT and Pilot Unit reactors but there are exceptions. If the matrix properties for two catalysts are different, the ranking of the two catalysts might be different in the MAT and PIlot Unit reactors.
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| 2. |
- Grahn, Mattias, et al.
(författare)
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A novel experimental technique for estimation of molecular orientation in zeolite
- 2007
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Ingår i: Studies in Surface Science and Catalysis. - 0167-2991. ; 170, s. 724-731
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Tidskriftsartikel (refereegranskat)abstract
- FTIR spectroscopy in combination with polarized light and an ATR probe coated with a b-oriented ZSM-5 film was for the first time used to determine the orientation of adsorbed molecules in the ZSM-5 structure. Two adsorbates were studied, n-hexane and p-xylene and the results agreed with previously reported results obtained by other experimental techniques.
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| 3. |
- Alfredsson, Viveka, et al.
(författare)
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Formation mechanism of mesoporous silica formed with triblock copolymers; effect of salt addition
- 2005
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Ingår i: Studies in Surface Science and Catalysis. - 0167-2991. ; 158, s. 97-104
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Tidskriftsartikel (refereegranskat)abstract
- SBA-15 was synthesised with Pluronic P104 ((EO)(27)-(PO)(61)-(EO)(27))) its Structure promoter at 45 degrees C, with and without NaCl (1.0 M) added to the Synthesis Mixture. TEOS (tetraethyl orthosilicate) was used as silica source. The formation process was studied by in-situ SAXS/SAXD using synchrotron light. Addition of salt affects the micellar size, initial cell-parameter of the 2-D hexagonal phase (p6mm) as well as the kinetics of the aggregation of the polymer-silica composite. The effects caused by the salt are explained by a general ionic effect. The salt makes the aqueous Solution more polar and hence a worse solvent for the polymer. The ethylene oxide chains of the polymer will be more solvophobic. This leads to a larger aggregation number ofthe micelles as well as to a stronger interaction between them.
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| 4. |
- Alfredsson, Viveka, et al.
(författare)
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In-situ studies of the formation mechanism of SBA-15
- 2005
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Ingår i: Nanoporous Materials IV, 156. - 0444517480 ; 156, s. 69-74
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Konferensbidrag (refereegranskat)abstract
- The formation process of SBA-15 has been investigated by time resolved TEM, in-situ SAXS/SAXD and in-situ NMR. The synthesis was done at 35 degrees in acidic solution with tetramethylorthosilicate as the silica source and Pluronic P123 as the structure directing amphiphile. The initially formed silica-polymer composite consists of flocs of spherical micelles in a silica matrix. The micelles then coalesce forming rods that eventually pack into the ordered array of which SBA-15 consists.
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