Hindered diffusion of residue narrow cuts through polycarbonate membranes

Chen, Zhentao; Chen, Xu; Gao, Jinsen; Zhao, Suoqi; Xu, Zheng

doi:10.1002/aic.12124

Cited by 17 publications

(26 citation statements)

References 43 publications

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“…The results of our previous study showed that the diffusion coefficients of AVR fractions through four membranes are time‐dependent . To illustrate this, the diffusion coefficients of three fractions among three residues through 15‐nm pore size membranes are plotted against experimental time in Figure .…”

Section: Resultsmentioning

confidence: 94%

“…The diffusion experiments were performed using a diaphragm diffusion cell described in detail elsewhere . A brief summary of the diffusion cell is given below.…”

Section: Methodsmentioning

confidence: 99%

“…Diffusion coefficient measurements were performed using the diaphragm diffusion cell mentioned above. The method for measuring diffusion coefficient is described in detail elsewhere . A brief description is given below.…”

Section: Methodsmentioning

confidence: 99%

“…An aqueous solution of potassium chloride at 298 K was used to determine β in this study. The method is described elsewhere and the diaphragm cell constants with the four membranes are provided in our previous study …”

Section: Methodsmentioning

confidence: 99%

“…In our previous study, Athabasca oil sand bitumen vacuum residue (AVR) was separated by a supercritical fluid extraction and fractionation (SFEF) technique, and hindered diffusivities of five AVR SFEF fractions through polycarbonate membranes were investigated . The results showed that the hindered degree of diffusion for the fractions is higher than the predicted value from the Renkin equation, which derives from a hydrodynamic theory model of noninteracting spherical particles moving along the centerline of the cylindrical pore.…”

Section: Introductionmentioning

confidence: 99%

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Effect of composition and configuration on hindered diffusion of residue fractions through polycarbonate membranes

et al. 2012

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Diffusion behavior of narrow fractions of three residues and subfractions of a residue through four polycarbonate membranes was investigated using a diaphragm cell at 308 K. The results show that the diffusivities of fractions with similar molecular weight behaved differently. Comparisons among SAR subfractions (saturates, aromatics, and resins) of the same fraction show that saturates has the largest diffusion coefficient, followed by aromatics, and then resins. The diffusion coefficients of fractions fall among that of their subfractions. The regular variation of diffusivity along with the properties for fractions with similar molecular weight is an indication of the difference in their diffusivities resulting from the difference in their compositions and structures. Hindrance factors of the subfractions through membranes with small pores have a similar variation trend as their diffusion coefficients. The hindrance factors of the feedstocks in 50 and 80 nm pore size membranes are mostly larger than 0.90, but the values in 15 nm membranes range from 0.55 to 0.81. The study not only indicates that the diffusional limitations are significant in pores with the typical hydrotreating catalyst size but composition and configuration have an effect on the hindered diffusion of residue molecules. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1369–1377, 2013

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Section: Resultsmentioning

confidence: 94%

“…The diffusion experiments were performed using a diaphragm diffusion cell described in detail elsewhere . A brief summary of the diffusion cell is given below.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of composition and configuration on hindered diffusion of residue fractions through polycarbonate membranes

et al. 2012

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Insight into the intraparticle diffusion of residue oil components in catalysts during hydrodesulfurization reaction

et al. 2014

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in Wiley Online Library (wileyonlinelibrary.com)Well-defined and uniform pore structure catalysts were used to study the intraparticle diffusion of fractionated Saudi vacuum residue under hydrodesulfurization (HDS) reaction conditions. HDS rates of residue oil cuts with different molecular weights are determined as functions of pore size, temperature, and pressure in a trickle-bed reactor. Credible intrinsic and bulk diffusivities of organosulfur compounds in residue oil were obtained for the first time, from the apparent and intrinsic reaction kinetic constants. Intrinsic diffusivities ranged from 2 3 10 27 to 8 3 10 27 cm 2 /s for the residual oil molecules; diffusivity decreases with increasing molecular weight of the residual oil. The intrinsic diffusivity for molecular weights $1000 Daltons increases with pore size for pores <70 nm, but is nearly independent of pore size for pores >70 nm. The diffusivity dependences on pore size and molecular weight suggest that the onset of restricted diffusion occurs for ratios of molecular diameter to pore diameter of $0.04. Figure 5. Relationship between ln(C 0 /C t ) and SHSV 21for Sa-14# narrow cut over catalyst with particle sizes of 0.128 and 0.675 mm, respectively.

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Restrictive diffusion and hydrodesulfurization reaction of dibenzothiophenes over NiMo/SBA‐15 catalysts

et al. 2022

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Macromolecular organosulfur compounds encountered resistance when diffusing in catalyst pore channels during the hydrotreating process. Quantitative insights into the effects of the catalyst pore size and the reactant molecule size on the diffusivities can guide the optimization of the catalyst structures. Herein, a heavy oil macromolecular dibenzothiophene compound, 2,8-di-(4-pentyl phenyl)dibenzothiophene (2,8-DPPDBT), was synthesized. Three NiMo-supported SBA-15 based catalysts with different pore sizes, but similar active phase dispersions were controllably fabricated. The reaction network of 2,8-DPPDBT HDS was proposed. The diffusion behaviors of 2,8-DPPDBT, along with 2,8-dimethyl dibenzothiophene (2,8-DMDBT) and dibenzothiophene (DBT) in three SBA-15 pore channels, were systematically investigated through the reaction kinetic method. A restrictive factor, F(λ), was correlated by F(λ) = (1 À λ) 8.5 to determine the relationship between the effective diffusivity and the ratio of the molecule-to-pore size (λ). This empirical correlation provided sound theoretical guidance on the design of highly efficient heavy oil hydrodesulfurization catalysts.

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Hindered diffusion of residue narrow cuts through polycarbonate membranes

Cited by 17 publications

References 43 publications

Effect of composition and configuration on hindered diffusion of residue fractions through polycarbonate membranes

Effect of composition and configuration on hindered diffusion of residue fractions through polycarbonate membranes

Insight into the intraparticle diffusion of residue oil components in catalysts during hydrodesulfurization reaction

Restrictive diffusion and hydrodesulfurization reaction of dibenzothiophenes over NiMo/SBA‐15 catalysts

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