Model based analysis of the effect of 2-ethylphenol addition to n-decane in fluid catalytic cracking over a series of zeolites

The catalytic cracking of n-decane (C10) purely, representing the conventional gasoil feed, and in admixture with 2-ethylphenol (EP), as a model component for HDO bio-oil, is investigated in a fixed-bed reactor over three faujasites. It was observed that EP induces faster deactivation with time-on-stream (TOS), which was more pronounced when materials with low mesoporous surface area were employed. The gasoline selectivity was also shown to increase more steeply with TOS for an EP containing feed. A 5-lump FCC kinetic model, including selective deactivation functions, was developed and incorporated into a transient reactor model to assess the obtained data and account for the observed effects. With the aid of the model, the above trends were rationalized by an increase in the value of the frequency factors, related to the feed conversion into coke and gasoline. The FCC kinetic model was subsequently integrated into a riser reactor model for pilot level simulations, via the extrapolation of the results obtained based on the transient model for the fixed-bed reactor to the steady-state behavior of a riser reactor. In particular, a unique deactivation factor Phi, reflecting catalyst condition, was introduced in the model for the latter reactor to adequately account for the deactivation functions determined making use of the data acquired in the former. Simulation results demonstrate the significance of the first meters of the riser, as well as the effect of operation parameters, i.e, Phi, EP addition in the feed, inlet catalyst-to-oil ratio, on conversion and selectivities

Efficient Direct Brown Coal Liquefaction with Sulfided Co/SiO₂ Catalysts

Efficient Direct Brown Coal Liquefaction with Sulfided Co/SiO₂ Catalyst

Influence of the Synthesis Protocol on the Catalytic Performance of PHI-Type Zeolites for the Dehydration of Lactic Acid

Acrylic acid is an important basic chemical and a key starting compound for a variety of consumer products. Today, acrylic acid is still produced from fossil-based propene. If acrylic acid were produced from bio-based lactic acid, this would be an important step towards sustainability. The gas-phase dehydration reaction of lactic acid to acrylic acid was performed over eight-membered ring PHI-type zeolites in the Na+ and K+-form. A few variations in the synthesis procedure of PHI-type zeolite made a big difference in the performance during the catalytic reaction due to differences in the physical and chemical properties, especially the accessibility of the pores. The catalysts were characterized with ICP-OES, XRD, CO2 physisorption, SEM and 27Al MAS NMR. The calcination resulted in a partial collapse of the PHI structure. In the case of Na,K-PHI with a low surface area, the catalysis tends to take place on the outer surface, while in the case of Na,K-PHI with a high surface area the catalysis can also take place within the pore system. This has a considerable influence on the selectivity of the catalysts

Influence of the Synthesis Protocol on the Catalytic Performance of PHI-Type Zeolites for the Dehydration of Lactic Acid

Acrylic acid is an important basic chemical and a key starting compound for a variety of consumer products. Today, acrylic acid is still produced from fossil-based propene. If acrylic acid were produced from bio-based lactic acid, this would be an important step towards sustainability. The gas-phase dehydration reaction of lactic acid to acrylic acid was performed over eight-membered ring PHI-type zeolites in the Na+ and K+-form. A few variations in the synthesis procedure of PHI-type zeolite made a big difference in the performance during the catalytic reaction due to differences in the physical and chemical properties, especially the accessibility of the pores. The catalysts were characterized with ICP-OES, XRD, CO2 physisorption, SEM and 27Al MAS NMR. The calcination resulted in a partial collapse of the PHI structure. In the case of Na,K-PHI with a low surface area, the catalysis tends to take place on the outer surface, while in the case of Na,K-PHI with a high surface area the catalysis can also take place within the pore system. This has a considerable influence on the selectivity of the catalysts

Production of High-Octane Fuel Components by Dehydroalkylation of Benzene with Mixtures of Ethane and Propane

The production of superior fuel components from natural gas was studied using a feed stream comprising ethane, propane, and benzene. For a better understanding of the different reactions occurring, product distributions of more simple reaction networks with only two of the three components are also presented. The dehydroalkylation reaction was conducted over a Pt–H-MFI catalyst at temperatures between 300 and 400 °C and a pressure of 6 bar. Three reaction cycles were conducted with intermittent regeneration with hydrogen to remove coke deposits. The research octane number of the received liquid fraction was calculated as a measure of quality of the produced alkylaromatic fuel components. The research octane number of the liquid fraction could be increased from 99 to at least 103 via dehydroalkylation with a mixture of cheap and abundant alkanes from natural gas

An EPR study on the enantioselective aziridination properties of a CuNaY zeolite

A CuNaY catalyst was prepared and used to study the enantioselective aziridination of styrene, with PhI2NTs as the nitrogen source, in the presence of a bis(oxazoline) chiral modiÐer. The chiral modiÐer used was a diimine ligand, (S)-([)-2,2@-isopropylidenebis(4-phenyl-2-oxazoline). EPR spectroscopy provides the Ðrst direct experimental evidence for the formation of a copper(II)-bis(oxazoline) complex inside the Y zeolite pores after stirring the calcined catalysts with the chiral ligand using acetonitrile as solvent. The copper complexes possess square pyramidal and square planar symmetries, with spin Hamiltonian parameters analogous to those of the equivalent homogeneous complex dissolved in solution. These copper(II) complexes accounted for at least 40% of all available copper within the ion exchanged CuNaY catalyst and represent one Cu(II)-bis(oxazoline) complex per supercage. The remaining uncomplexed Cu(II) ions remain solvated to the acetonitrile molecules. After the aziridination reaction was carried out in the presence of styrene and PhI2NTs, EPR evidenced the selective loss of the signal due to the copper(II)-bis(oxazoline) complex with square pyramidal and square planar symmetries but practically no loss in overall Cu(II) content. This was explained on the grounds of a changing co-ordination environment of the encapsulated complex. However when PhI2NTs was added separately to the catalyst a dramatic loss in Cu(II) signal intensity was observed. These results are discussed in terms of the reaction mechanism in operation