A study of the catalytic steam cracking of heavy crude oil in the presence of a dispersed molybdenum-containing catalyst

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.     

The Formation of Mn-Ce Oxide Catalysts for CO Oxidation by Oxalate Route: The Role of Annealing Conditions

Catalysis Letters - A series of Mn-Ce oxide catalysts with Mn:Ce?=?1 was synthesized by oxalate route under different annealing conditions. The physicochemical properties were...     

Di-(2-ethylhexyl) dithiophosphoric acid surface protected gold nanoparticles: micellar synthesis, stabilization, isolation, and properties

Gold nanoparticles (AuNPs) were synthesized in the organic solution by means of the reduction of HAuCl₄ by hydrazine in reverse micelles of oxyethylated surfactant Triton N-42, with decane as the dispersion medium. To isolate the powder of particles, the micelles were destroyed with chloroform in the presence of di-(2-ethylhexyl) dithiophosphoric acid as a surface protecting agent. According to the results of several experiments, the yield is within the limits of 90–98%, calculated for gold. The obtained preparations are dark blue hydrophobic powders containing aggregated but not agglomerated gold nanoparticles, as well as microcrystals (∼0.08–0.2 μm) of NaCl. The powders get re-dispersed in weakly polar organic solvents with the formation of colloidal solutions. The shape of the nanoparticles is spherical. Their nuclei are gold single crystals with a narrow size distribution; their diameter (d _Au) is about two times as large as the diameter of the aqueous nucleus (d _c) of initial micelles: d _Au = 7.7 ± 1.4 nm (d _c = 3.6 nm) and 8.8 ± 1.5 nm (4.6 nm). The preparations were studied by means of dynamic light scattering, atomic force microscopy, transmission electron microscopy, UV–vis spectroscopy, IR spectroscopy, X-ray powder diffraction, and thermogravimetric and elemental analyses. In the case of the particles with d _Au = 8.8 nm, the product is a mixture of AuNPs and the salt with the molar ratio Au/NaCl ≈ 1:4.54, while the gross composition of AuNPs per one gold atom is estimated as Au(C₁₆H₃₄O₂PS₂Na∙2N₂H₄)_0.16 with the number of gold atoms in one particle ∼21,000.     

Development of new catalytic systems for upgraded bio-fuels production from bio-crude-oil and biodiesel

The investigation of upgraded bio-fuels production processes was carried out via the development of efficient catalysts for oxy-organic hydrodeoxygenation (HDO) processes. It was found that Ni–Cu catalysts are more attractive than single Ni catalysts in HDO under mild conditions. Copper facilitates the nickel oxide reduction at temperatures lower than 300 °C. Moreover, copper prevents methanization of oxy-organics at 280–350 °C. The catalyst supports play also a key role in hydrotreatment of oxygen-containing compounds. Screening of catalyst supports showed that CeO₂ and ZrO₂ are most effective in the target processes because of possible additional activation of oxy-compounds on the support surface. The prepared catalysts have non-sulfided nature and can be used for upgrading of bioliquids with a low sulfur content.     

Guaiacol hydrodeoxygenation in the presence of Ni-containing catalysts

A series of Ni-containing catalysts supported on different materials has been tested in the hydrodeoxygenation of guaiacol, a compound modeling the products of biomass fast pyrolysis. The reaction has been carried out in an autoclave at 320°C and a hydrogen pressure of 17 MPa. The main guaiacol hydrodeoxygenation products are cyclohexane, 1-methylcyclohexane-1,2-diol, and cyclohexanone (which result from aromatic ring reduction). A guaiacol conversion scheme explaining the formation of the main products is suggested. The highest activity is shown by the Ni-containing catalysts on SiO₂ and SiO₂-ZrO₂ supports prepared by the sol-gel method. According to X-ray diffraction and electron microscopic data, the high activity of these catalysts is due to the high concentration of dispersed nickel as reduced films on the surface of the silicate structures. The catalysts offer promise for refining the biomass fast pyrolysis products (bio-oil) into hydrocarbon fuel.     

Investigating the process of heavy crude oil steam cracking in the presence of dispersed catalysts. II: Investigating the effect of Ni-containing catalyst concentration on the yield and properties of products

The process of heavy crude oil (HCO) steam cracking under a batch regime at 425°C in the presence of Ni-containing nanodispersed catalyst (0.3–2.0 wt % with respect to Ni) is investigated. It is established that using this catalyst facilitates the upgrading of semi-synthetic oil produced from HCO: the Н: С ratio rises (in comparison to steam cracking with no catalyst), and the sulfur content and viscosity are reduced. The Н: С ratio in the liquid products grows slightly along with the catalyst content, but the yield of liquid products falls from 81 to 76% during the process with a simultaneous increase in the yield of coke and gaseous products (from 8 to 13 and from 2 to 4 wt %, respectively). Catalyst with coke residue is investigated by means of XRD and TEM. It is shown that nanosized particles of the Ni9S8 phase with sizes of 15–40 nm form from the catalyst precursor (Ni(NO₃)₂ · 6H₂O) under the process conditions. The selection and investigation of catalytic systems for heavy crude oil cracking in the presence of superheated steam, along with optimization of the process conditions, are required to further enhance the efficiency of the upgrading process.     

Catalytic steam cracking of heavy crude oil with molybdenum and nickel nanodispersed catalysts

The catalytic steam cracking (CSC) of heavy crude oil with high amount of sulfur (4.3 wt %) and high-boiling fractions (>500°C) is studied using Mo and Ni nanodispersed catalysts under static conditions (in an autoclave) at 425°C. Experiments on thermal cracking, steam cracking, and catalytic cracking without water are performed to compare and identify the features of CSC. The relationship between the composition and properties of liquid and gaseous products and process conditions, the type of catalyst, and water is studied. Using Ni catalyst in CSC raises the H: C ratio (1.69) in liquid products, compared to other types of cracking, but also increases the yield of coke and gaseous products, so the yield of liquid products falls. When Mo catalyst is used in CSC, low-viscosity semi-synthetic oil with a higher H: C ratio (1.70) and the lowest amount of sulfur in liquid products (2.8 wt %) is produced. XRF and HRTEM studies of the catalyst-containing solid residue (coke) show that under CSC conditions, nickel is present in the form of well-crystallized nanoparticles of Ni₉S₈ 15–40 nm in size, while molybdenum exists in two phases: MoO₂ and MoS₂, the ratio between which depends on the conditions of the transformation of heavy crude oil. The findings indicate that CSC is a promising process for improving heavy crude oil.