Fundamental studies of retrograde reactions in direct liquefaction

Serio, Michael A.; Solomon, P.R.; Kroo, E.; Charpenay, S.; Bassilakis, R.

doi:10.2172/5348671

Cited by 10 publications

(15 citation statements)

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“…Results and Discussion -A summary of our data on water pretreatment of our coals is shown in Brandes,1987;Brandeset al, 1989;Khan et al, 1989). liquefactionare at a minimum where pyrolysistar yieldsare at maximum, which is contrary to previousstudies on Ilquefacatlon (Serio,et al, 1989(Serio,et al, , 1990 and expectations. The Pittsburgh coal is an exceptionhere,also.…”

Section: Sem/x-ray Analysis Of Pretreatment Residuescontrasting

confidence: 61%

Fundamental studies of water pretreatment of coal

Serio¹,

Kroo²,

Solomon³

et al. 1991

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During the past year, a set of water pretreatment experiments was completed on four different coals (Zap, Wyodak, Illinois No. 6, and Pittsburgh No. 8) under two different ranges of conditions (very short and very long pretreatment times). Additional water pretreatment experiments were done with Illinois No. 6 and Pittsburgh seam bituminous coals at selected intermediate points to cover the range of pretreatment behavior. The objective of this work was twofold: 1) to determine how bituminous coals behave during water pretreatment under similar conditions: 2) to verify the effects of water pretreatment on liquefaction yields, which previously hav_ been shown to be different,than expectations, i.e, the conditions which give the highest pyrolysis tar yield relative to the raw coal (short pretreatment times) give the lowest liquefaction yields relative to the raw coal and vice versa.

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Section: Sem/x-ray Analysis Of Pretreatment Residuescontrasting

confidence: 61%

Fundamental studies of water pretreatment of coal

Serio¹,

Kroo²,

Solomon³

et al. 1991

Self Cite

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“…However, for higher rank coals such as the bituminous coal studied in this work, an increase in reactivity was observed after demineralisation. This effect can be ascribed to a physical effect such as surface area or to a decrease in molecular order (active sites concentration) [10] due to loss of fluidity. The latter effect can be seen in Table 1, where the demineralised sample does not present signs of plasticity according to its free swelling index (FSI) value, while the parent coal has an FSI of 6.5.…”

Section: Combustibility Assessment In Tga-msmentioning

confidence: 99%

Coal structure and reactivity changes induced by chemical demineralisation

Rubiera

Arenillas

Pevida

et al. 2002

Fuel Processing Technology

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The aim of this work was to determine the influence that an advanced demineralisation procedure has on the combustion characteristics of coal. A high-volatile bituminous coal with 6.2% ash content was treated in a mixture of hydrofluoric and fluorosilicic acids (HF/H 2 SiF 6). Nitric acid was used either as a pre-treatment, or as a washing stage after HF/H 2 SiF 6 demineralisation, with an ash content as low as 0.3% being attained in the latter case. The structural changes produced by the chemical treatment were evaluated by comparison of the FTIR spectra of the raw and treated coal samples. The devolatilisation and combustibility behaviour of the samples was studied by using a thermobalance coupled to a mass spectrometer (TGA-MS) for evolved gas analysis. The combustibility characteristics of the cleaned samples were clearly improved, there being a decrease in SO 2 emissions.

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“…Thus, one might speculate that if lignite were composed substantially of such linkages, it would simply fall to pieces under liquefaction conditions-unless retrograde reactions were very facile. Indeed, in previous work [4], we found that two different polymers presumably consisting largely of the β-ether linkage showed both facile cleavage and extensive crosslinking. However, this observation was clouded by the fact that side reactions could not readily be eliminated in the polymer synthesis (using mercuric trifluoracetate of 4-allylphenol and eugenol (2-methoxy-4-allylphenol)), and we were never able to obtain polymers that gave the correct elemental analysis.…”

Section: Synthesis Of C-c-o Polymers Preparation and Characterizationmentioning

confidence: 79%

“…Also, since 3-methoxy-4-hydroxyphenethyl alcohol (homovanillyl alcohol) is commercially available, we also proceeded with the synthesis of the 3-methoxy analog of the above polymer. Except for the missing methyl side chain, this polymer (-(m-OMe)C 6 H 3 -O-CH 2 CH 2 -) is identical to the polymer that could not be obtained in high purity via direct polymerization of eugenol during the previous contract [4]. With these two polymers in hand, we would then be in a very good position to see whether the unusual cleavage and crosslinking behavior of the -C-C-O-linkage in lignins is mirrored by the behavior of the same linkage in alcohol-free polymers.…”

Section: Synthesis Of C-c-o Polymers Preparation and Characterizationmentioning

confidence: 90%

“…The apparent absence of competitive crosslinking for the -(C 6 H 4 -O-CH 2 CH 2 ) n -polymer is in marked contrast to the polyeugenol (nominal structure -[C 6 H 3 (o-Me)-O-CH(CH 3 )CH 2 ] n -) that we prepared and studied briefly in the previous contract [4]. With that polymeric model of low-rank coal, we saw facile thermal generation of monomeric and other small fragments, but rapid crosslinking, as evidenced by low yields not only in pyrolysis but also from liquefaction in a very good hydrogen-donor solvent.…”

Section: Pyrolysis-fims Of the -C-c-o-polymersmentioning

confidence: 97%

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