Effect of Si/Al2 Ratio Over Zeolite Beta in Steam and Direct Catalytic Cracking of n-dodecane

In this study, ZSM-5 and beta zeolites, which constitutes the most industrially important artificial zeolite species., were synthesized and the effects of synthesized zeolite in catalytic cracking were investigated. ZSM-5 and beta zeolite were synthesized by varying synthesis time, synthesis method and calcination temperatures. The composition of the synthesis was kept constant and than compared with ultrasonic method and hydrothermal method.ZSM-5 and beta zeolite derivatives were synthesized with changing the synthesis method. Beta zeolite is obtained as a result of the synthesis with low temperature in 20 minutes with using of ultrasonic method. On the other hand, ZSM-5 zeolite is achieved at the end of the synthesis with high temperature in 72 hours with using of hidrotermal method.The X-Ray Powder Diffraction (XRD) patterns and Scanning Electron Microscopy (SEM) images of ZSM-5 zeolites showed that the crystal structure and phase purity of ZSM-5 increased with increase in synthesis time and not affected by the calcination temperature. Otherwise, the crystal structure and phase purity of beta zeolite increased with increase in calcination temperature.To determine the catalytic performances of the products, the catalytic cracking processes were performed. First of all, thermal cracking was realized without catalyst for comparison with the others. Then, catalytic cracking was carried out with CaO, Al2O3, SiO2, natural zeolite, ZSM-5 and beta zeolite.Compairing the results, the catalytic efficiency of the synthesized products were higher than the others. Yield of over 70 % was obtained with synthesized ZSM-5 and zeolite beta.

Seeds induced Beta zeolite synthesis with low SDA for n-heptane catalytic cracking reaction

Steam cracking of heavy oil was studied at 425 °C and 2.0 MPa in the presence of disperse catalysts based on iron and molybdenum in a slurry reactor. The catalysts were prepared via in situ decomposition of water soluble precursors of the metal salts. In the steam cracking, the yield of a total of liquid products increased against that in thermal cracking (80 and 77 wt %, respectively). The use of disperse monometal catalysts (iron- and molybdenum-containing), as well as the bimetal catalyst for catalytic steam cracking (CSC) of heavy oil resulted in an increase in the total of liquid products yield up to 85–92 wt %. In addition, CSC provided a higher yield of light fractions (T boil <350 °C) than steam and thermal cracking processes, as well as a decrease in viscosity and density in comparison to those of the raw feedstock.

Results are presented from studying the steam cracking of heavy oil at a temperature of 425°C and a pressure of 2.0 MPa over dispersed iron and molybdenum based catalysts in a slurry reactor. The catalysts are synthesized through the decomposition of water-soluble precursors of metal salts in situ. The yield of upgraded oil (the sum of liquid products) is found to grow with steam cracking, in comparison to thermal cracking (80 and 77%, respectively). The use of dispersed monometallic (iron- or molybdenum-containing) catalysts and a bimetallic catalyst for the catalytic steam cracking (CSC) of heavy oil increases the yield of SOPs. In addition, the yield of light fractions (Тb < 350°C) in the CSC process is found to grow in comparison to steam and thermal cracking, and the viscosity and density of products falls, relative to the initial feedstock.

Catalytic cracking performance of alkaline-treated zeolite Beta in the terms of acid sites properties and their accessibility

Mild-acid-assisted thermal or hydrothermal dealumination of zeolite beta, its regulation to Al distribution and catalytic cracking performance to hydrocarbons

Defect engineering to boost catalytic activity of Beta zeolite on low-density polyethylene cracking

The features of the steam cracking of heavy crude oil in the presence of a dispersed molybdenumcontaining catalyst are studied. The effect of water, the catalyst, and process conditions on the composition and properties of the products of the thermal conversion of heavy crude oil is determined in experiments on thermal cracking, steam cracking, catalytic cracking in the absence of water, and hydrocracking. A complex analysis of the resulting products is conducted; the catalyst-containing solid residue (coke) has been studied by XRD and HRTEM. The effect of the process temperature (425 and 450°C) and time on the yields and properties of the resulting products is studied. The efficiencies of hydrocracking and steam cracking for the production of upgraded low-viscosity semisynthetic oil are compared; the fundamental changes that occur in the catalyst during the studied processes are discussed. Some assumptions about the principle of the catalytic action of the molybdenum-containing catalyst in the steam cracking process are made.

Gasoline upgrading by self-etherification with ethanol on modified beta-zeolite

A series of lanthanum/beta-zeolite catalysts was prepared via hydrothermal ion exchange, and characterized by inductively coupled plasma–atomic emission spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and ammonia temperature-programmed desorption. The lanthanum-doping effect on beta-zeolite catalysts was investigated through catalytic cracking of supercritical methylcyclohexane under the system pressure of 4.0 MPa and the mass flow rate of . For lanthanum/beta catalyst of the Cat-2 type, the gas yield of 28.3% and heat sink of could be achieved at the temperature of 700°C, much higher than those for the pure beta zeolite without lanthanum modification and for the thermal pyrolysis. Correspondingly, Cat-2 has a better performance on coking inhibition with the reduction of 56.2 and 29.5% at 700°C compared to beta zeolite and thermal cracking. Therefore, it was indicated that beta zeolite with the suitable lanthanum content, still maintaining its high activity and stability of the zeolite framework at high temperature due to lanthanum doping, had a great contribution to high heat sink and coking inhibition at high temperature.

Synthesis and characterization of composite molecular sieves comprising zeolite Beta with MCM-41 structures

Second-generation biomass (BM) can be produced in amounts that meet worldwide fuel demands. However, BM favors parallel and undesirable reactions in its transformation chain. We circumvent this problem by first modifying BM by ketalization, giving a user-friendly liquid we named BP (bio-petroleum). This study converted a representative compound of BP, DX (1,2:3,5-di-O-isopropylidene-α-D-xylofuranose), mixed with n-hexane by beta zeolites and catalysts containing beta zeolite. Beta zeolite showed low coke and high liquid product yields in converting this mixture (having 30 wt. % DX) into hydrocarbons in a fixed-bed reactor at 500 °C with a space velocity of 16 h−1 (0.3 catalyst/feed). Its performance was further improved by steam treatment (lowering the coke yield by lowering the acid site density) or incorporation into a catalyst (improving DX participation due to the active sites in the matrix). Further, by changing the conversion process from a fixed bed to a fluidized cracking unit, a much larger amount of the deactivated catalyst could be used (catalyst/feed = 3), remarkably reducing oxygenates and fully converting DX. Additionally, the green hydrocarbon efficiency (olefin, aromatics, furans, and cyclo-alkanes) of DX was approximately 77%. Hence, beta catalysts were shown to have a great potential to provide green fuels for future bio-refineries.

Plastics and climate change—Breaking carbon lock-ins through three mitigation pathways

Deactivation of ZSM-5 zeolite during catalytic steam cracking of n-hexane

A conceptual design of the catalytic oxidative cracking (COC) of hexane as a model compound of naphtha is reported. The design is based on experimental data which are elaborated through a structural design method to a process flow sheet. The potential of COC as an alternative to steam cracking (SC) is discussed through comparing the key differences between the two processes. The presence of Li/MgO catalyst in the COC process (i) induces hexane cracking at lower operation temperatures (575 °C) than in SC (800 °C) and (ii) controls the olefin distribution by increasing the ratio of (butylene + propylene)/ethylene. The product distribution, and thus the separation train of both processes, is different. Catalytic oxidative cracking is designed to maximize propylene and butylene production, while steam cracking is designed to maximize ethylene production. In comparison to SC, the COC process is more energy efficient and consumes 53% less total duty for a production capacity of 300 kton/year of light olefins. However, a preliminary economic evaluation illustrates that the loss of valuable feedstock as a result of combustion of part of the naphtha feed makes the COC process economically less attractive than SC.