Acid demineralization with critical point drying: A method for kerogen isolation that preserves microstructure

Suleimenova, Assiya; Bake, Kyle D.; Ozkan, A; Valenza, John J.; Kleinberg, R.L.; Burnham, Alan K.; Ferralis, Nicola; Pomerantz, Andrew E.

doi:10.1016/j.fuel.2014.07.005

Cited by 43 publications

(43 citation statements)

References 29 publications

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“…From the results of the SEM observations, it was obvious that the CPD method preserved the microstructure and was effective in the drying of the pretreated cellulosic biomass samples. It was a similar result to the study on the application of the CPD for the accurate surface area measurement of the other samples [28].…”

Section: Resultssupporting

confidence: 82%

Critical Point Drying: An Effective Drying Method for Direct Measurement of the Surface Area of a Pretreated Cellulosic Biomass

et al. 2018

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Abstract:The surface area and pore size distribution of Eucalyptus samples that were pretreated by different methods were determined by the Brunauer-Emmett-Teller (BET) technique. Three methods were applied to prepare cellulosic biomass samples for the BET measurements, air, freeze, and critical point drying (CPD). The air and freeze drying caused a severe collapse of the biomass pore structures, but the CPD effectively preserved the biomass morphology. The surface area of the CPD prepared Eucalyptus samples were determined to be 58-161 m 2 /g, whereas the air and freeze dried samples were 0.5-1.3 and 1.0-2.4 m 2 /g, respectively. The average pore diameter of the CPD prepared Eucalyptus samples were 61-70 Å. The CPD preserved the Eucalyptus sample morphology by replacing water with a non-polar solvent, CO 2 fluid, which prevented hydrogen bond reformation in the cellulose.

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Section: Resultssupporting

confidence: 82%

Critical Point Drying: An Effective Drying Method for Direct Measurement of the Surface Area of a Pretreated Cellulosic Biomass

et al. 2018

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“…Some methods can quantify maturity but provide no direct characterization of chemical composition (for example, vitrinite reflectance, VRo [10,11] or Rock-Eval pyrolysis [12,13]). Chemically specific methods (such as 13 C NMR [14] or elemental analysis) require destructive sample preparation (kerogen isolation through acid demineralization [12,15]) that is significantly more time consuming than the measurement itself. Furthermore, such alterations to the samples limit the ability to correlate the molecular composition with the local mineralogy.…”

mentioning

confidence: 99%

Direct correlation between aromatization of carbon-rich organic matter and its visible electronic absorption edge

Ferralis

Liu

Bake

et al. 2015

Carbon

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The evolution of the electronic absorption edge of type I, II and III kerogen is studied by diffuse reflectance UV-Visible absorption spectroscopy. The functional form of the electronic absorption edge for all kerogens measured is in excellent agreement with the "Urbach tail" phenomenology. The Urbach decay width extracted from the exponential fit within the visible range is strongly correlated with the aliphatic/aromatic ratio in isolated kerogen, regardless of the kerogen type. No correlation is found between the decay width and the average size of aromatic clusters, which is explained in terms of a non-linear increase in optical absorption with increasing size of the aromatic clusters determined by 13 C NMR. Further, absorption spectra calculated with density functional theory calculations on proxy ensemble models of kerogen are (Nicola Ferralis) 2 in excellent agreement with the experimental results. The correlation of the decay width with conventional maturity indicators such as vitrinite reflectance is found to be good within a particular kerogen type, but not consistent across different kerogen types, reflecting systematic variations in bulk composition for different type kerogen types with the same vitrinite reflectance. Thus, diffuse reflectance visible absorption spectroscopy is presented as a rapid, calibrated and non-destructive method to monitor both the maturity and the chemical composition of kerogen. The chemical insight of kerogen in relation to its optical absorption provided by this methodology may serve for rapid screening of kerogen for electronics and optical devices in place of functionalized produced carbon.Common methods of estimating thermal maturity are informative but involve a compromise between accuracy, level of detail, and simplicity [4]. Some methods can quantify maturity but provide no direct characterization of chemical composition (for example, vitrinite reflectance, VRo [10,11] or Rock-Eval pyrolysis [12,13]). Chemically specific methods (such as 13 C NMR [14] or elemental analysis) require destructive sample preparation (kerogen isolation through acid demineralization [12,15]) that is significantly more time consuming than the measurement itself. Furthermore, such alterations to the samples limit the ability to correlate the molecular composition with the local mineralogy.

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“…Kerogen in source rocks contains nanoscale pores that are believed to control the storage and transport of hydrocarbons in gas shale and potentially tight oil formations. , Although less is known about kerogen’s physical structure than its chemical composition, tools are being developed that could enable rapid progress in microstructural investigation. First, a method of preparing representative kerogen samples has been developed . Although the traditional acid demineralization procedure results in a kerogen whose chemical composition is representative of the subsurface, the procedure causes kerogen-hosted pores to collapse.…”

Section: Other Analyses and Future Directionsmentioning

confidence: 99%

“…Although the traditional acid demineralization procedure results in a kerogen whose chemical composition is representative of the subsurface, the procedure causes kerogen-hosted pores to collapse. A recent refinement, called acid demineralization with critical point drying, preserves the kerogen microstructure and provides material suitable for further microstructural analysis . Using kerogen samples prepared with this technique, the distribution of distances between pairs of carbon nuclei in kerogen has been measured by X-ray diffraction, and those data have been inverted to produce a physical model of microporous kerogen .…”

Section: Other Analyses and Future Directionsmentioning

confidence: 99%

Toward Molecule-Specific Geochemistry of Heavy Ends: Application to the Upstream Oil Industry

Pomerantz

2016

Ind. Eng. Chem. Res.

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Detailed molecular analysis of the composition of petroleum is typically performed on only the light (volatile) fraction, using analyses involving gas chromatography (GC). Heavier (nonvolatile) components such as kerogen, bitumen, and asphaltenes, which are relevant to conventional reservoirs and particularly to unconventional gas shale and tight oil formations, are not amenable to analysis by GC and instead are typically studied by more phenomenological techniques. This report describes a suite of analytical techniques that can provide sufficient average molecular information on the heavy ends (defined as the nonvolatile fraction) to be useful for a variety of industrial applications, expanding the discipline of molecule-specific geochemistry into the non-GC amenable fractions of petroleum materials. Heavy ends are composed of the elements C, H, N, S, and O, and the bonding environments of each can be measured by various solid state spectroscopies: nuclear magnetic resonance (NMR) and infrared (IR) spectroscopies for C, H, and O; X-ray absorption near-edge structure (XANES) spectroscopy for S and N. Additionally, advances in mass spectrometry, including techniques such as laser desorption laser ionization mass spectrometry (L 2 MS), can be used to measure the molecular weight and dominant molecular architecture of asphaltenes. Moreover, higher-order structures can be measured: samples of kerogen with representative pore geometry can be prepared, and those pore systems are analyzed with techniques such as X-ray diffraction and neutron scattering. Colloidal structures of asphaltenes can be measured with a variety of techniques, which reveal a hierarchical aggregation structure. These analyses provide sufficient structural data to enable structure−property and structure− function relationships to be determined, which can be applied to the characterization of conventional and unconventional resources. In gas shale and tight oil formations, which contain abundant inorganic minerals as well as kerogen, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) is used for simultaneous analysis of mineralogy, kerogen content, and maturity, typically performed at the wellsite. In conventional reservoirs, spatial variations in the asphaltene concentration measured by downhole fluid analysis logging tools are being interpreted with a recently developed equation of state to address upstream issues such as reservoir connectivity, tar mat formation, and fault block migration. As more heavy end analyses are developed, further scientific knowledge and industrial applications of heavy end geochemistry are anticipated.

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Acid demineralization with critical point drying: A method for kerogen isolation that preserves microstructure

Cited by 43 publications

References 29 publications

Critical Point Drying: An Effective Drying Method for Direct Measurement of the Surface Area of a Pretreated Cellulosic Biomass

Critical Point Drying: An Effective Drying Method for Direct Measurement of the Surface Area of a Pretreated Cellulosic Biomass

Direct correlation between aromatization of carbon-rich organic matter and its visible electronic absorption edge

Toward Molecule-Specific Geochemistry of Heavy Ends: Application to the Upstream Oil Industry

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