Effect of temperature, solvent/coal ratio and beneficiation on conversion and product distribution from direct coal liquefaction

Barraza, Juan; Coley-Silva, Edwin; Piñeres, Jorge

doi:10.1016/j.fuel.2015.12.072

Cited by 35 publications

(10 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…From Figure 1, it was observed that conversion increased with an increase in temperature. This trend is consistent with the data from a previously reported studies [14,15]. The Waterberg and Highveld float fractions achieved a carbon conversion of 50.7 wt.…”

Section: Effect Of Temperature On Conversionsupporting

confidence: 93%

Direct Liquefaction of 2 South African Bituminous Coals and their Beneficiated Float Fractions

Uwaoma¹,

Strydom²,

Matjie³

et al. 2018

ASETH-18,ACABES-18 &Amp; EBHSSS-18 Nov. 19-20 2018 Cape Town (South Africa)

View full text Add to dashboard Cite

The direct liquefaction of South African coal fines and their density separated (float) fractions were carried out under moderate conditions in a laboratory autoclave. The liquefaction temperature ranged between 380 and 420 oC, using tetralin as a solvent and an initial nitrogen gas pressure of 3 MPa. Results from the liquefaction tests showed that the carbon conversion and oil yields were high for the float fractions when compared to the coal fines. Waterberg and Highveld coal float fractions achieved a high carbon conversion of 50.7 wt % daf and 52.7 wt % daf respectively, compared with < 42 wt % daf carbon conversion for the coal fines. The effectiveness of the carbon conversion was correlated with the reactive macerals and the surface area of the individual samples. It was observed that the density separated coal fraction, which has a higher surface area, higher vitrinite content and higher reactive macerals content yielded higher extraction efficiencies. The residues and extracts obtained during the liquefaction tests were characterised using nuclear magnetic resonance spectroscopy, proximate and ultimate analyses. The analytical results indicated that the residue showed a slight decrease in calorific value and aliphatic components, with a lower H/C ratio and a higher ash content. Also, the results showed that using the float fractions of South African coals at a moderate liquefaction temperature could be beneficial in the production of liquid fuel.

show abstract

Section: Effect Of Temperature On Conversionsupporting

confidence: 93%

Direct Liquefaction of 2 South African Bituminous Coals and their Beneficiated Float Fractions

Uwaoma¹,

Strydom²,

Matjie³

et al. 2018

ASETH-18,ACABES-18 &Amp; EBHSSS-18 Nov. 19-20 2018 Cape Town (South Africa)

View full text Add to dashboard Cite

show abstract

“…As expected, DCL was highly dependent on the temperature of the process. 31 The increase in temperature from 350–400 °C led to an increase in the conversion of the tetralin-soluble fraction. The decomposition of molecules is enhanced by performing DCL at a temperature above pyrolysis (360 °C).…”

Section: Resultsmentioning

confidence: 99%

“…TTS was subjected to vacuum distillation on a high vacuum line and an oil bath set to 300 °C to remove the tetralin and then subjected to Soxhlet extraction with heptane as a solvent. The extraction worked by slow diffusion of analytes from the sample matrix to the extraction solvent 31 and yielded a heptane soluble (HS) and a heptane insoluble (HIS) fraction. A toluene Soxhlet extraction was performed on the HIS, which further gave a toluene soluble (TS) and toluene insoluble fraction (TIS).…”

Section: Experimental Sectionmentioning

confidence: 99%

Multistep Fractionation of Coal and Application for Graphene Synthesis

et al. 2021

View full text Add to dashboard Cite

Despite its complex structure, coal has shown to be a promising precursor for graphene synthesis by chemical vapor deposition (CVD). However, the presence of heteroatoms and aliphatic chains in coal can lead to defects in the graphene lattice, preventing the formation of pristine graphene layers. Therefore, the goal of this study was to formulate a multistep coal fractionation scheme to extract and characterize the most aromatic fractions and explore their potential as graphene precursors. The scheme consisted of direct coal liquefaction under different conditions, Soxhlet extraction with heptane then toluene, and preparative liquid chromatography on silica gel using heptol solutions with different heptane/toluene ratios. The fractions obtained by this process were analyzed by proton nuclear magnetic resonance, thermogravimetric and elemental analyses, and automated SAR-AD (saturates, aromatics, resins-asphaltene determinator) separations. This characterization allowed the identification of two aromatic fractions with and without heteroatoms, which were subsequently used for graphene synthesis by CVD on nickel and copper foils. Raman spectrometry revealed that both fractions primarily formed defect-free multilayered graphene with approximately 11 layers on nickel due to the high solubility of carbon and the defect-healing effect of nickel. On the other hand, these fractions generated amorphous carbon on copper due to the high solubility of hydrogen in copper, which competed with carbon. Molecules in the more aromatic heteroatom-free fraction still contained alkyl pendant substituents and did not share the same planarity and symmetry to form defect-free graphene on copper. Thus, the quality of graphene was governed by the substrate on nickel and by the precursor quality on copper. When deposited directly on lacey carbon-coated copper grids of a transmission electron microscope, the heteroatom-free fraction gave rise to much larger graphene domains. The presence of heteroatoms promoted the formation of small self-assembled agglomerates of amorphous carbon.

show abstract

“…Un trabajo reciente (2016) 18 revela el avance alcanzado en este país en el estudio de la licuefacción de carbón, donde han evaluado el papel de la relación solvente a carbón (S/C), efecto de la temperatura y de la fracción inorgánica sobre la extensión de la licuefacción directa.…”

Section: Estudios En Colombiaunclassified

Conversión de Carbón a Productos Líquidos mediante Despolimerización Asistida por Solventes: una Revisión de los Fundamentos y Avances en la Región

Martínez

Garbán

Gamboa³

et al. 2017

RCTU-UPSE

View full text Add to dashboard Cite

En la búsqueda de transformar el carbón mineral en materiales más sencillos, se han ensayado varios procedimientos químicos de despolimerización (licuefacción, pirólisis, hidrogenación). El tratamiento con solventes luce como una alternativa que tiene la ventaja de requerir bajas temperaturas. Varios modelos macromoleculares han sido propuestos para explicar la interacción solvente-carbón. Se presenta una exposición de las características y antecedentes de la despolimerización, su aplicación en carbones y la potencialidad de la técnica para diversificar la industria carbonífera en los países de la región.Abstract Looking for the coal conversion into simpler materials, several procedures have been assayed (liquefaction, pyrolysis, and hydrogenation). The solvent treatment of coal looks as an alternative with the advantage of requiring low temperatures. Several macromolecular models have been proposed to explain the solvent-coal interaction. In this study, a comprehensive review of coal depolymerization is exposed, its feasibility and the potential of the technology to diversify the coal-bearing industry in the countries of the region.

show abstract

Effect of temperature, solvent/coal ratio and beneficiation on conversion and product distribution from direct coal liquefaction

Cited by 35 publications

References 27 publications

Direct Liquefaction of 2 South African Bituminous Coals and their Beneficiated Float Fractions

Direct Liquefaction of 2 South African Bituminous Coals and their Beneficiated Float Fractions

Multistep Fractionation of Coal and Application for Graphene Synthesis

Conversión de Carbón a Productos Líquidos mediante Despolimerización Asistida por Solventes: una Revisión de los Fundamentos y Avances en la Región

Contact Info

Product

Resources

About