Phase equilibria of water-hydrocarbon (pentane to heavy oils) systems in the near-critical and supercritical water regions - A literature review

Adeniyi, Kayode I.; Zirrahi, Mohsen

doi:10.1016/j.supflu.2021.105356

Cited by 17 publications

(6 citation statements)

References 130 publications

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“…Both experimental observation and computational simulation confirm that the heavy oil cannot be well-dispersed or dissolved in supercritical water. ,, Therefore, the reaction system of heavy oil and supercritical water is generally determined as an upper water-rich phase and a lower oil-rich phase. ,,,,,,− Of these, the water-rich phase mainly comprises the water and small-molecule compounds, and the oil-rich phase mainly comprises the heavy hydrocarbons (resins and asphaltenes) and solid particles (MO n and M–OH), as illustrated in Figure . The interface between the water-rich phase and the oil-rich phase will significantly hinder the SCWU reactions . As shown in Figure , the D addition occurs more with aliphatic hydrocarbons than with aromatic hydrocarbons in both cases of MO n and M–OH.…”

Section: Resultsmentioning

confidence: 96%

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Metal Hydroxide-Catalyzed Heavy Oil Upgrading in Supercritical Water: Deuterium Tracing Study

Chen,

et al. 2024

Energy Fuels

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Conversion of heavy oil is urgent as most of the explored fossil oil reserves and renewable raw biodiesel can be categorized as heavy oil. Supercritical water upgrading (SCWU) is a green and promising technology for heavy oil conversion, but the hydrogen-donating capacity of pure water is inadequate. This study adopts transition-metal hydroxide (M−OH) to enhance the in situ hydrogen-donating capacity of water for the first time. Both M− OH and the corresponding metal oxide nanoparticle (MO n ) of one post-transition metal (Al) and five transition metals (Cr, Cu, Fe, Ni, Zn) are tested. The SCWU conditions are selected as 425 °C, 60 min, water-to-oil ratio of 4:1, catalyst-to-oil ratio of 1:10, and water density of 308 kg m −3 . Deuterium oxide (D 2 O) instead of H 2 O is used as the reaction medium for a deuterium tracing study. Results indicate that the different metal-based MO n nanoparticles display various effects on heavy hydrocarbon cracking, gasification, coke suppression, and D addition reactions. The overall performance is found to be on the order of NiO > Cr 2 O 3 > Fe 2 O 3 > CuO > Al 2 O 3 > ZnO. Compared to MO n , M−OH can generally improve the oil yield and H/C ratio and reduce the coke yield simultaneously. The mechanism analysis suggests that the M−OH decomposition behavior under hydrothermal conditions is the primary cause by which MO n and lattice H 2 O are generated in the oil-rich phase. The lattice H 2 O can not only take part in SCWU reactions but also suppress coke formation. In conclusion, M−OH is a promising catalyst as it combines the good dispersibility and catalytic activity of MO n nanoparticles and the low cost of water-soluble inorganic metal salts (M-IAc) but does not result in any corrosive species, such as inorganic acid from M-IAc.

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Section: Resultsmentioning

confidence: 96%

“…The interface between the water-rich phase and the oil-rich phase will significantly hinder the SCWU reactions. 65 As shown in Figure 2, the D addition occurs more with aliphatic hydrocarbons than with aromatic hydrocarbons in both cases of MO n and M−OH. This is just due to their different phase behaviors.…”

Section: Performance Of M−oh and Momentioning

confidence: 82%

Metal Hydroxide-Catalyzed Heavy Oil Upgrading in Supercritical Water: Deuterium Tracing Study

Chen,

et al. 2024

Energy Fuels

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“…The dielectric constant of water decreases from ~78.49 at room temperature to ~34.79 at 200°C, ~20.39 at 300°C and ~14.07 at 350°C. The hydrogen bonds become less persistent, and the HTW possesses the similar property of polar organic solvents, which make the organic compounds and gaseous products completely solvated in HTW 38,39 . As shown in Figure 1a, due to the weak interaction of hydrogen bonds, mass transfer resistance between interfaces would disappear in the supercritical water phase, which can effectively promote heterogeneous reaction rates 40 .…”

Section: The Role Of Water For Co2 Hydrogenation In Hydrothermal Cond...mentioning

confidence: 99%

CO₂ reduction into formic acid under hydrothermal conditions: A mini review

Liu

Zhong

Wang

et al. 2022

Energy Science & Engineering

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Converting CO2, a major component of greenhouse gas in the atmosphere, into value‐added fine chemicals is beneficial from environmental and economic aspects. Except for various methods for CO2 reduction such as thermal catalysis, photocatalysis, electrocatalysis and biological reduction, hydrothermal reduction of CO2 to organics is becoming a novel and promising strategy. The hydrogen formed in situ from high‐temperature water could avoid the serious issues of hydrogen storage and transportation. This paper summarizes the recent advances on CO2 conversion to formic acid with metal‐ and biomass‐based compounds under hydrothermal conditions mainly focusing on the role of high‐temperature water, autocatalysis mechanism of metal reductants, and interfacial catalysis mechanism of metal/metal oxides. The effects of several experimental variables including temperature, reaction time and pH of the solution on formic acid yield are systematically illustrated as well. Finally, future efforts for fundamental researches and industrial applications of hydrothermal CO2 reduction are discussed.

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“…SCW is compressed liquid water existing above its saturation vapor pressure (p = 0.4-22.1 MPa) and below or near the critical temperature (T = 150-370 • C) [18]. SCW is a new environmentally friendly solvent with acid/alkali catalytic functions and excellent extraction abilities.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Conversion of Oil Shale over Fe or Ni Catalysts under Sub-Critical Water

Che,

Wu,

Shen

et al. 2024

Processes

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Sub-critical water is an environment-friendly solvent. It is widely used for the extraction of various organic compounds. It can be used to dissolve and transport organic matter in oil shale. In this study, the conversion of oil shale was synergistically catalyzed by the addition of Fe or Ni to the Fe inherent in samples under sub-critical water conditions. Oil shale can be converted to gas, oil and residues of oil. Thermogravimetric (TG) analysis results presented that the weight loss of raw oil shale was up to 15.85%. After sub-critical water extraction, the weight loss rate of the residues was reduced to 8.41%. With the application of a metal catalyst, Fe or Ni, the weight loss of residues was further reduced to 7.43% and 6.57%, respectively. According to DTG curves, it was found that there were two weight-loss rate peaks. The decomposition process of kerogen in oil shale could be divided into two cracking processes. One is decomposed at a high velocity at around 420 °C, and another is decomposed at a low velocity at around 515 °C. Gas chromatography (GC) results of gas products indicated that Fe or Ni could contribute to producing normal alkanes, such as methane, ethane, propane, etc., which are produced by the hydrogenation of alkenes via hydrogen transfer during the conversion process of kerogen. Gas chromatography-mass spectrometry (GC–MS) was conducted to analyze the components of the liquid products. The results showed that n-alkanes, iso-alkane, oxygenated hydrocarbons and aromatic compounds were the major components of the kerogen cracking products. When Ni was introduced as a catalyst, the contents of aromatic compounds and oxygenated hydrocarbons in the liquid products were increased from 19.55% and 6.87% to 22.38% and 13.77%, respectively. This is due to the synergistic effect of the addition of Ni with the inherent Fe in oil shale under sub-critical water which ensures kerogen is more easily cracked to produce aromatic compounds and oxygenated hydrocarbons.

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Phase equilibria of water-hydrocarbon (pentane to heavy oils) systems in the near-critical and supercritical water regions - A literature review

Cited by 17 publications

References 130 publications

Metal Hydroxide-Catalyzed Heavy Oil Upgrading in Supercritical Water: Deuterium Tracing Study

Metal Hydroxide-Catalyzed Heavy Oil Upgrading in Supercritical Water: Deuterium Tracing Study

CO₂ reduction into formic acid under hydrothermal conditions: A mini review

Catalytic Conversion of Oil Shale over Fe or Ni Catalysts under Sub-Critical Water

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Phase equilibria of water-hydrocarbon (pentane to heavy oils) systems in the near-critical and supercritical water regions - A literature review

Cited by 17 publications

References 130 publications

Metal Hydroxide-Catalyzed Heavy Oil Upgrading in Supercritical Water: Deuterium Tracing Study

Metal Hydroxide-Catalyzed Heavy Oil Upgrading in Supercritical Water: Deuterium Tracing Study

CO2 reduction into formic acid under hydrothermal conditions: A mini review

Catalytic Conversion of Oil Shale over Fe or Ni Catalysts under Sub-Critical Water

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Product

Resources

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CO₂ reduction into formic acid under hydrothermal conditions: A mini review