Classification of Water Sorbed in Coal on the Basis of Congelation Characteristics

Norinaga, Koyo; Kumagai, Hitoshi; Hayashi, Jun Ichiro; Chiba, Tadatoshi

doi:10.1021/ef970183j

Cited by 86 publications

(86 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Presence of cations can also influence swelling of lignite in water (Allardice et al 2003). Norinaga et al (1998) found three types of water in coals of different ranks and reported also on molecular modeling results confirming expansioncontraction conformational transitions of coal molecules in response to the change in the number of water molecules. Suuberg et al (1993) published evidences that in addition water can affect diffusion processes within the lignite structure.…”

Section: Resultsmentioning

confidence: 78%

Fluoride Anion Binding by Natural Lignite (South Moravian Deposit of Vienna Basin)

Pekař

2008

Water Air Soil Pollut

View full text Add to dashboard Cite

Natural lignite from South Moravia was tested for the sorption of fluoride anion in concentration range from 5·10 −5 to 8·10 −4 mol/l. The lignite removes majority of fluorides and only about 13% of sorption is reversible upon leaching in pure water. Sorption data can be fitted by both Freundlich and Langmuir equations and both isotherms indicate presence of two principal sorption sites or steps. The sorption is fast, at least 90% of final sorbed amount is removed during the first 10 min but kinetic data show a complex pattern with temporary increase of fluoride concentration. This is attributed to complexity of lignite-water interactions, lignite soaking and swelling in aqueous media. Foreign ions and pH showed only slight influence on the sorbed amount. Natural lignite can be considered as a potential low-cost defluoridation agent that is effective at various solution chemistries and also at low, but still overlimit, fluoride concentrations.

show abstract

Section: Resultsmentioning

confidence: 78%

Fluoride Anion Binding by Natural Lignite (South Moravian Deposit of Vienna Basin)

Pekař

2008

Water Air Soil Pollut

View full text Add to dashboard Cite

show abstract

“…The plot for the m/z 18 ion shows an initial peak extending from approximately 85 to 225°C (apex at 125°C) that can be assigned to the drying of "sorbed" water. In this context, sorbed water is defined as the free (bulk), bound, and nonfreezable water described by Noringa et al 21,22 A second peak beginning at approximately 340°C whose apex is at approximately 500°C can be assigned to chemically formed pyrolytic water observed by other researchers. 1,20 Similar sorbed water drying peaks are observed in the m/z 20 trace (D 2 O) and m/z 19 (HDO) trace.…”

Section: Effect Of the Lignite:deuterium-labeled Water Ratiomentioning

confidence: 99%

A Study of the Hydrogen Exchange Reactions Occurring during Loy Yang Lignite Pyrolysis Using Deuterium-Labeled Water and Gas Chromatography–Mass Spectrometry Analysis

Larcher

Kajitani

2011

Energy Fuels

View full text Add to dashboard Cite

Hydrogen exchange has been studied during lignite pyrolysis by heating mixtures of an oven-dried (105°C) Loy Yang lignite and deuterium-labeled water (D 2 O) in a quartz U-tube reactor. A typical experiment consisted of heating the lignite from ambient temperature to 500 ( 2°C at 20°C/min under a flow of nitrogen. A higher-heating rate experiment (6°C/s) was also performed. The collected tar fractions were analyzed by gas chromatography and mass spectrometry, which allowed detailed analysis of individual components. Inspection of the mass spectra of some of the components showed changes that reflected deuterium had been incorporated into their molecular structure during pyrolysis. The relative extent of deuterium incorporation was quantitated by mass fragmentography of selected ions, with the molecular ion in most cases being used. Four compounds were chosen for detailed analysis: 1-methylnaphthalene, 2-methylphenol, 1-octadecene, and n-octadecane. The pyrolysis experiments showed that a significant amount of deuterium was incorporated into the aromatic and phenolic components of the tar, while the amount of deuterium incorporated into the 1-alkene and n-alkane components was much smaller. A series of experiments was completed to determine the influence of experimental parameters such as the heating rate, purge gas flow, and amount of deuterium-labeled water present. Additional experiments using in-line mass spectrometry monitored the fate of the deuterium-labeled water during pyrolysis and the generation of chemically produced pyrolytic water. Reaction mechanisms for the observed hydrogen exchange reactions are proposed, and the significance of these to the overall lignite pyrolysis process is discussed.

show abstract

“…This topic has been extensively studied in soil research and sludge dewatering. There are a number of interpretations available on the types of water associated with soil, sludge, and coal [7][8][9][10][11][12].…”

Section: Forms Of Watermentioning

confidence: 99%

Determination of Free and Bound Water in Fine Coal Filter Cake

Patil¹,

Parekh²

2004

Coal Preparation

View full text Add to dashboard Cite

The bound water in fine coal filter cake represents the water that cannot be removed using mechanical dewatering techniques. The amount of bound water in a fine coal filter cake, in other words, represents the moisture content achievable by an ideal dewatering technique. In this study the dilatometer technique was used to measure the bound and free water in a fine coal filter cake. Results showed that addition of cationic (0.25 kg=t) and non-ionic (1 kg=t) surfactants reduced the bound water content in the filter cake from 13.73% to 3.72% and 8.28%, respectively. Decrease in bound water content was attributed to the adsorption of surfactants on the coal surface, which increased the coal hydrophobicity. Addition of 10 g=t of cationic and anionic flocculants also reduced the bound water content from 13.73% to 4.58% and 6.63%, respectively, which was attributed to the replacement of surface water molecules with the polymer. Based on the free and bound water data, ideal dewatering curves were developed for both surfactants and flocculants.

show abstract

Classification of Water Sorbed in Coal on the Basis of Congelation Characteristics

Cited by 86 publications

References 29 publications

Fluoride Anion Binding by Natural Lignite (South Moravian Deposit of Vienna Basin)

Fluoride Anion Binding by Natural Lignite (South Moravian Deposit of Vienna Basin)

A Study of the Hydrogen Exchange Reactions Occurring during Loy Yang Lignite Pyrolysis Using Deuterium-Labeled Water and Gas Chromatography–Mass Spectrometry Analysis

Determination of Free and Bound Water in Fine Coal Filter Cake

Contact Info

Product

Resources

About