Combustion Chemistry Investigation of Liquid and Solid Fuels

Abstract: The aim of this work was to study the combustion of liquid and solid fuels with the emphasis on intermediates and products. Depending on the structure and the complexity of the fuel different reactors and methods were used. Small-scale laboratory reactors were built and chemical analysis and evaluation methods were developed.

Heptane. N-heptane was combusted in an atmospheric premixed laminar flame burner (fuel/air ratio 1.0). Quantification and identification of the species profiles were performed using GC/MS, which was directly connected to the sampling probe. Complementary, the flame was modeled using a semi empirical heptane mechanism.

Gasoline. Two gasoline qualities were combusted in an atmospheric premixed laminar flame burner (fuel/air ratio 1.0). The gasolines were European certificate gasoline (EUCG) and California phase 2 reformulated gasoline (P2 RFG). The EUCG contained higher amounts of aromatics and cyclohexane compared to P2 RFG. P2 RFG contained approximately 11% MTBE (EUCG none) and also higher amounts of isooctane. GC/MS was used for the identification and quantification of the species profiles.

Bio Diesel. Rapeseed oil, rapeseed methyl ester (RME), and diesel (Swedish environmental class 1) were combusted at 550°C in a reactor. Similarities and differences between the combustion products were qualitatively investigated. Solid phase extraction (SPE) followed by GC/MS analysis was used for the sampling and identification of combustion species.

Wood. Wood from eight conifer species, eight birch species, and two willow clones were examined. The samples were pyrolysed in nitrogen at 550°C using a small reactor and the results were analyzed qualitatively. Both direct sampling of the gaseous emissions and SPE technique were used. GC/MS and GC/FTIR/FID performed the chemical analysis.

The results showed that different fuels demands detailed analyses of their combustion products, due to their environmental and health effects and also from a technological point of view. The combustion products could be derived from the original fuel components and the major part of the emissions consisted of unburned and partly burned fuel components. Seemingly, the results obtained from the small reactors can be valuable in the predictions of experiments performed in full-scale devices.