Importance of carbon active sites in the gasification of coal chars

The release of nitrogen oxides during char combustion

This paper reviews analytical methods that have been developed for characterizing complex liquid mixtures derived from fossil fuels. The analysis of fractions with masses up to ∼400−450 u normally involves gas and liquid chromatography, coupled with mass spectrometry (GC−MS and LC−MS, respectively). However, these techniques cannot readily be adapted to examine samples that contain higher-molecular-mass materials. Chromatographic and mass spectrometric methods are often limited by the volatility of the samples, while liquid chromatographic methods may be limited by solubility in the solvents used. Materials of higher mass are characterized using methods that have been developed to overcome the limitations imposed by volatility and solubility in common solvents. As outlined in the text, they have been the subject of some debate. Much of the work that indicates upper mass limits of ∼1000−1500 u for coal tars, pitches, and petroleum asphaltenes can be explained in terms of limitations of the particular analy...

Pritchard Ernest

Papers

Investigation of nitrogen compounds in coal tar products. 2. Basic fractions