Investigation of catalytic conversion of Fischer-Tropsch wax on Pt/ALSBA-15 and Pt/beta zeolite catalysts

Because of the more serious problems with the environment (e.g. greenhouse effect) and the crude oil supply (e.g. import dependence) the use of fuels and lubricants produced from renewable feedstocks have come to the front nowadays. The Fischer-Tropsch wax (60–80% of the Fischer-Tropsch products) which is produced on synthesis gas from different sources (biological or waste), is a mixture of high molecular weight (C20-C60) n-paraffins, which are in solid state (high pour point) at normal conditions. The products (fuels and base oils) which can be produced from this paraffin mixture have high quality and have fewer negative effects on the environment (practically zero sulphur- and nitrogen content, low aromatic content, excellent application properties) thus they do not demand changes in the fuel supply infrastructure and in the engine constructions. The isomerization of high molecular weight n-paraffins can be effectively carried out on bifunctional catalysts. There are only a few indications about the application of metal catalysts on mesoporous carrier in the literature. Consequently our objective was to investigate some Pt/AlSBA-15 (SBA: Santa Barbara Amorphous) catalysts which have not been investigated in detail in this reaction system yet, and compare its properties with a Pt/beta zeolite catalyst which has been recommended for this reaction earlier. The applicability and catalytic activity of Pt/AlSBA-15 and Pt/beta zeolite catalysts of 0.5% platinum content for the selective isomerization of Fischer-Tropsch wax was investigated in the present experiment. The experiments were carried out in a high-pressure microreactor system in continuous operation and on a catalyst with steady-state activity. The main properties of the feedstock which was a mixture of paraffin produced by Fischer-Tropsch synthesis (the synthesis gas was produced from biomass) were: n-paraffin content (C18-C57): 97.4%, sulphur content: <5 mg/kg, pour point: 72 °C. In the experiment the following process parameters were applied: T = 275–375 °C, P = 40–80 bar, LHSV = 1.0–3.0 h-1, H2/hydrocarbon ratio: 400–800 Nm3 /m3 . The composition of the products was determined by gas chromatography. From the catalysts with different support the best results were gained on the catalysts with AlSBA-15 support, and with increasing temperature the yield of liquid products (C5+) decreased, but until 325 °C this value was above 93% in every case. In case of the beta zeolite high amount of cracking took place. Increasing the pressure shifted back the hydrocracking reactions (with the increasing number of moles) so it had a decreasing effect on the volume of the gas products and the lower contact time (higher liquid hour space velocity) had the same effect. In the gas products mainly branched isobutane was identified, which indicated that the cracking enacted partly after the isomerization reactions. The isoparaffin contents of the liquid products in the function of process parameters increased with increasing temperature and decreased with increasing pressure and LHSV in every case while other parameters were kept constant. Based on the isoparaffin contents of the different fractions it can be concluded that on Pt/AlSBA-15 catalyst at advantageous process parameter combinations (T = 300–325 °C (C11-C20)/ 275–300 °C (C21-C30), P = 40–80 bar, LHSV = 1.0–2.0 h-1) the catalyst was applicable to produce C11-C20 and C21-C30 fractions with high isoparaffin content (63.5–85.6% and 34.1–58.7%) with adequate yields (29.9–36.6% and 46.2–58.8%). We experienced that the gas oil fractions having the lowest pour point were obtained in the case of high concentrations of 5-methyl isomers. The C21-C30 fraction is a high viscosity index (VI ≥ 125) base oil. The selectivity of the target product fractions was high, and based on these facts the selective isomerization of the Fischer-Tropsch wax can be a new application area of the Pt/AlSBA-15 catalys

MgO-SiO2 Catalysts for the Ethanol to Butadiene Reaction: The Effect of Lewis Acid Promoters

MgO SiO2 samples, having the composition of natural talc (NT); were obtained by co-precipitation (CP) and wet kneading (WK) methods. The materials were used as catalysts of the ethanolto-1,3-butadiene reaction. ZnO, Ga2O3 and In2O3 were tested as promoters. The catalyst WK gave the highest 1,3-Butadiene (BD) yield among the non-promoted catalysts because of the high specific surface area and strong basicity. Results suggested that over the neat WK catalyst the acetaldehyde coupling to crotonaldehyde was the rate-determining process step. Formation of crotyl alcohol intermediate was substantiated to proceed by the hydrogen transfer reaction between crotonaldehyde and ethanol. The crotyl alcohol intermediate becomes dehydrated to BD or, in a disproportionation side reaction, it forms crotonaldehyde and butanol. The promoter was found to increase the surface concentration of the reactant and reaction intermediates, thereby increases the rates of conversion and BD formation. The order of promoting efficiency was Zn>In>Ga

Investigation of producing modern base oils

Modern lube oils are prepared from base oils (base oil mixtures) and additives. The allotted quality parameters and the proper application properties are assured by the harmonical integration of these components. Some key lube oil properties depend on the quality of the base oil. For example a new demand has raised in the area of engine oils in the last couple of years: the demand is to contribute to the lower emission of the vehicles. This means the development of engine oils with low sulphated ash, low metal, sulphur and phosphorous content (“low SAPS” engine oils). In order to reach the adequate properties, the base oil (which is the main component of the engine oils) has to be produced with modern and advanced processes. The conventional base oil production line has its own disadvantages and limitations, so the catalytic processes were spread to enhance the viscosity index and to reduce the pour point of the base oils. It was necessary to develop and apply base oil production processes and technologies which are flexible to the crude oil quality and can produce environmentally friendly base oils with high viscosity index. To reach these goals the most adequate technologies are the catalytic base oil production processes. In the experimental section of this paper the results of hydroisomerization of wax from Hungarian crude oil on Pt/zeolite/Al2O3 catalyst are presented. Based on our experiments we established that with hydroisomerization base oils with very high or extra high viscosity index and low pour point can be produced from high molecular weight paraffinic hydrocarbon mixture. These base oils with low sulphur and aromatic content are appropriate, for example to produce energy efficient and environmentally friendly engine oils

Possibilities of application of polyisobutenyl succinic anhydride derivatives of various molecular structures

Detergent-dispersant (DD) effect is one of the most important properties of lubricants and fuels. To ensure these properties various types of additives are used in increasing amount in the performance additive packages. Among them ashless types and mostly polyalkenyl succinic anhydride derivatives are applied in high volumes. In this paper the main advantages of the ashless additives are presented showing the dependence of their properties on the molecule structure (monosuccinimides, bissuccinimides, mixtures thereof and polysuccinimide). Additionally, the interactions with other additives are shown which can determine the main tribological properties of the lubricants