No abstract

The objective of this study is to get a fundamental understanding of role of surface oxygen-contained functional groups (OCFG) in adsorptive denitrogenation (ADN) of liquid hydrocarbons over activated carbon, and thus to improve the ADN performance of activated carbon through modification of surface chemistry of activated carbon. A set of activated carbon samples with different amount and distribution of OCFG was prepared by oxidative modification and thermal treatment of a commercial activated carbon. The prepared activated carbons were characterized by the temperature-programmed desorption coupled with mass spectrometry for the concentration of various OCFG, and evaluated in a fixed-bed adsorption system using a model fuel containing aniline, indole, quinoline, carbazole, and ethyl-carbazole. The results indicate that OCFG, especially the strong carboxyls, weak carboxyls and anhydrides, play a crucial role in determining the adsorptive performance of activated carbon for selective removal of nitrogen compounds from liquid hydrocarbons. The adsorption mechanism of the nitrogen compounds over activated carbon was discussed on the basis of the structure-performance correlation and the molecular simulation.

Identification and quantification of nitrogen compounds in five typical liquid hydrocarbon streams, including straight run gas oil, light cycle oil, and ultralow sulfur diesel derived from petroleum and coal liquids from the coal pyrolysis and the direct coal liquefaction, have been conducted by a combination of the modified solid phase extraction and gas chromatography with a mass spectrometry detector (GC−MS) and a nitrogen/phosphorus detector (GC−NPD). A simple and efficient method was applied for preisolating and concentrating the nitrogen compounds from the hydrocarbon matrix and coexisting oxygen-containing compounds. The identification and quantification results show that the coal-derived streams not only have much higher nitrogen content than the petroleum-derived ones but also contain quite different types of the nitrogen compounds. The major nitrogen compounds in the coal-derived streams are the basic nitrogen-containing compounds including aniline, quinoline, and their derivatives; while those in the petroleum-derived ones are the neutral nitrogen compounds, such as carbazole and its alkyl substituted derivatives. The implication of the analysis results on the fuel processing and deep denitrogenation is also discussed.

No abstract

No abstract