Papers by Keyword: Supported Catalysts

Abstract: The catalytic hydrotreatment of sunflower (SO), linseed (LO), coconut (CO), rapeseed (RO), and its soapstock derived acid oil (RS) over commercial Ni65%/SiO₂-Al₂O₃ catalyst was investigated to evaluate utilization feasibility of various vegetable oil feedstocks with different fatty acid content, composition, and saturation for marketable hydrocarbon production. The active metal loading of catalyst was characterized by XRF and its textural properties by N₂ sorption analysis. The hydrotreatment tests of different vegetable oils were carried out in solvent free medium, under initial H₂ pressure 10 MPa, at operating temperature 340 oC, and residence time 15 min using catalyst amount 5%. GC-FID and GC-MS analysis were used for estimation of dominant n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, and other hydrocarbon contents in obtained samples. Under studied hydrotreatment conditions complete conversion of different vegetable oils into marketable liquid renewable hydrocarbons without presence of oxygen containing substances was achieved. Highly active Ni65%/SiO₂-Al₂O₃ has remarkable selectivity to hydrocarbons produced by reaction pathways, where elimination of carbonyl groups occurs. The saturation of fatty acids in feedstock determines H₂ consumption, but influence on produced hydrocarbon production is insignificant. Depending on the fatty acid composition different saturated linear hydrocarbons with wide range of carbon chain length C5-C19 and similar calorific value 47.16-47.34 MJ/kg were produced in process. Overall liquid hydrocarbon yields were from 44.6 % to 78.1 %. The highest overall liquid saturated linear hydrocarbon yield was observed for feedstock with high amount of long chain fatty acids – SO, LO, RO and RS. Pure hydrocarbons obtained from vegetable oils depending on hydrocarbon composition can be used in various areas.

Abstract: CH4 and CO2 are greenhouse gases. Hence, their emission to the atmosphere must be controlled to avoid the global warming. Dry reforming of methane could provide a valuable tool in alleviating this problem as well as producing synthesis gas. This process is hampered by rapid catalyst deactivation due to carbon deposition and sintering of both the support and active metal. The presented study focuses on the experimental investigation the effect of addition of Calcium promoter to 1%Ni catalysts supported on a mixed 80%α-Al2O3 and 20%TiO2-P25 support. The performance of the developed catalyst was quantified by determining CH4 and CO2 conversions, synthesis gas ratio (H2/CO) and stability. Spent and fresh catalysts were characterized by TGA, SEM and EDS. Time on stream stability tests of the promoted catalyst showed that addition of limited amounts of Ca promoter would reduce carbon formation.

Abstract: Under microwave irradiation, the ternary CuMgAl-HTLcs precursors were synthesized and MoO₄^2- was loaded on the surface of these HTLcs. The results of XRD, FT-IR and SEM analysis indicated that the Mo anion was successfully loaded on the surface of the CuMgAl-HTLcs precursors. The activity of CuMgAl-31 for phenol hydroxylation was the highest, the conversion of phenol was 42.88% and ratio of catechol to hydroquinone was 2:1. CuMgAl-Mo-HTLcs advantageously increased the selectivity of hydroquinone with the ratio of hydroquinone to catechol reaching to 6:1 and about 4% conversion decreasing. Proposed the reaction mechanism of phenol hydroxylation by MoO₄^2- supported HTLcs.