An Investigation of the Effect of Pre-swelling on the Extraction Yield of Two Different Ranked Turkish Coals

Abstract

In this article, the effect of pre-swelling on the extraction yield of two Turkish coals was investigated. Supercritical toluene extraction and carbon disulfide/N-methyl-2-pyrrolidinone mixed solvent extraction at room temperature were the extraction methods employed. Ten different solvents were used to study the swelling behaviors of the coals. The swelling ratios were found dependent on the coal type, solvent basicity, and steric effect of the solvent used. The best swelling solvent identified was ethylenediamine for two coal samples. Pre-swelling enhanced the conversion and oil yield in supercritical toluene extraction. However, when using the mixed solvent extraction, the effect of pre-swelling was dependent on coal rank. Pre-swelling with ethylenediamine enhanced the extraction yield of Soma lignite while it decreased that of Nasifoglu coal.

Keywords:

• coal
• carbon disulfide/N-methyl-2-pyrrolidinone
• mixed solvent extraction
• solvent swelling
• supercritical toluene extraction

Notes

^a By difference.