Supporting Tungsten Oxide on Zirconia by Hydrothermal and Impregnation Methods and Its Use as a Catalyst To Reduce the Viscosity of Heavy Crude Oil

Abstract

Tungsten oxide was supported on zirconia via hydrothermal and conventional impregnation methods and used as a catalyst to reduce the viscosity of heavy crude oil without the addition of water. Their properties and viscosity reduction activity were compared. X-ray diffraction and the Rietveld method were used to characterize the crystal structure and determine the phase composition. The properties of catalysts were also measured by N2 adsorption–desorption, differential scanning calorimetry, a Hammett indicator, and ammonia temperature-programmed desorption. Compared with the impregnation method, the hydrothermal method facilitates the formation of strong tungsten–zirconia interaction and promotes the diffusion of tungstate on zirconia, hence leading to better-dispersed tungsten oxide, as well as more tetragonal zirconia and acid sites. Under the reaction conditions of 220 °C, 6 h, and 2 MPa, the catalysts prepared via the hydrothermal method exhibit higher viscosity reduction activity than those prepared by impregnation. It is found the catalytic activity mainly depends on the acidity of the catalyst. The catalyst containing 20 wt % tungsten prepared by the hydrothermal method can attain a viscosity reduction ratio of 82.2% and reduce the viscosity of oil from 5.74 Pa s (50 °C) to 1.02 Pa s. Different from the widely used aquathermolysis technique, the presence of water is not required and the viscosity of the treated oil will not regress, even over long periods of time.

Influence of calcination temperature on the activity of mesoporous CaO/TiO2–ZrO2 catalyst in the esterification reaction

“…However, due to wellperching of zirconia in the titania lattice and no formation of individual crystal of zirconia, the crystalline size was sharply reduced. Formation of zirconia phases resulted in increase of the crystalline size and CTZ-500 presented a greater crystalline size compared to CTZ-400 [34]. The same phenomenon was observed for the relative crystallinity where the relative crystallinity was increased by increasing the calcination temperature due to creation of appropriate medium to grow the crystals.…”

In situ catalytic upgrading of heavy crude oil through low-temperature oxidation

“…A comparison of elemental composition between the Xinjiang heavy oil and other heavy oils in previous studies has also been made in terms of catalytic reaction (Wang et al 2012;Xu et al 2012a;Qin and Xiao 2013). It is easy to find from Table 3 that the changing trends of elements are consistent with the Xinjiang heavy oil catalyzed by oilsoluble catalysts.…”

“…The reaction had been positively catalyzed and the molar ratio of CO 2 /CO of effluent gases increased by additives. Wang et al (2012) conducted a comparative study of the catalytic effect of tungsten oxide supported on zirconia via different methods to reduce the viscosity of heavy crude oil. With the heavy components converted into light ones and the removal of heteroatoms, the powdered catalyst prepared by the hydrothermal method reduced the viscosity of oil from 5740 to 1020 mPa s, a reduction of 82 %.…”

Plenty of Room at the Bottom: Nanotechnology as Solution to an Old Issue in Enhanced Oil Recovery

“…The studies carried out on the topic were focused mainly on the particles used as nanocatalysts, and a minor part dealt with the technologies used to increase the temperature in order to trigger the upgrading processes. The materials reported in the literature are: VO 2+ [142], Ni [36,37,[142][143][144][145][146], Fe [142,143,147], W [36,37,144,148], Mo [36,37,144], Cu [143,147], Zr [148], Co [147], Cr [147], Pd [147], C [149], SiO 2 [150], SiO 2 /nanoFe [151], K 3 PMo 12 O 40 [152], and nanoclays (montmorillonite (MMT), modified with a quaternary ammonium salt) [153].…”