Publisher Summary This chapter describes solvent extraction as one of the most commonly used techniques for studying the chemical properties of coal While solvent extraction of coal at temperatures below the onset of active thermal decomposition is a useful and important technique in studies of coal structure, it yields material of little commercial value However, considerable commercial importance exists for the application of extensive dissolution and thermal decomposition of coal in solvents in the liquefaction and refining of coal Degrading solvents can extract up to more than 90% of the coal at temperatures up to 400°C After extraction, the solvents can be recovered almost totally, substantially unchanged from solution As thermal degradation of coal occurs at these temperatures, the action of degrading solvents is presumed to depend on thermal action that produces smaller and more soluble fragments Tar oil fractions are often used as degrading solvents They contain a variety of chemical compounds but are not always recovered unchanged from coal solution; for example, anthracene oil fraction is changed on recycling

Solvent extraction of coal

Direct liquefaction of a Chinese brown coal and CO2 gasification of the residues

The role of sulphur in coal hydroliquefaction

We evaluated how gas-phase O3 interacts with residual petroleum hydrocarbons in soil. Total petroleum hydrocarbons (TPH) were 18 ± 0.6 g/kg soil, and TPH carbon constituted ∼40% of the dichloromethane-extractable carbon (DeOC) in the soil. At the benchmark dose of 3.4 kg O3/kg initial TPH, TPH carbon was reduced by nearly 6 gC/kg soil (40%), which was accompanied by an increase of about 4 gC/kg soil in dissolved organic carbon (DOC) and a 4-fold increase in 5-day biochemical oxygen demand (BOD5). Disrupting gas channeling in the soil improved mass transport of O3 to TPH bound to soil and increased TPH removal. Ozonation resulted in two measurable alterations of the composition of the organic carbon. First, part of DeOC was converted to DOC (∼4.1 gC/kg soil), 75% of which was not extractable by dichloromethane. Second, the DeOC containing saturates, aromatics, resins, and asphaltenes (SARA), was partially oxidized, resulting in a decline in saturates and aromatics, but increases in resins and asphaltenes. ...

John O. Golden

Papers

Noncatalytic Coal Liquefaction in a Donor Solvent. Rate of Formation of Oil, Asphaltenes, and Preasphaltenes

Kinetics of Sulfur Form Removal during Coal Hydrogenation