Investigation of Soot Formation During Partial Oxidation of Diesel Fuel

Abstract

Soot formation during partial oxidation is a major issue for hydrogen production from liquid hydrocarbon fuels. Measurements were made to investigate the sooting behavior of diesel fuel under variation of the main operating parameters temperature (T = 800 to 1300°C), pressure (p = 1 to 3 bar), equivalence ratio (U =1 to 3), and steam ratio (H 2 O/C = 0.2 to 0.6) at constant residence time. The experimental setup was a perfectly stirred/plug flow reactor (PSR/PFR system) providing conditions close to reality. The study proves that soot growth rate strongly depends on temperature, pressure, and equivalence ratio while adding water has a minor effect on soot growth. Experimental results were compared with a kinetic model developed by the Institut Français du Pétrole (IFP), predicting soot formation during the partial oxidation of liquid hydrocarbon fuels. The calculated amount of soot shows good agreement with the measured data.

The Influence of the Distributed Reaction Regime on Fuel Reforming Conditions

“…Vourliotakis et al [18] presented data on the partial oxidation of ethanol at temperatures of 791-804 C and O/C ratio of 1.5. Their results showed active partial oxidation reactions at timescales of 80 ms. Roth and Wirtz [19] evaluated the partial oxidation of diesel fuel using a reactor with a fixed residence time of 400 ms. The activity of partial oxidation reaction was affected by oxygen concentrations.…”

“…This additional oxygen was indicative of steam reforming reactions extracting oxygen from the steam releasing additional hydrogen. Roth and Wirtz [19] operated the reactor at residence times of 400 ms and a reactor temperature of 1300 C. An increase in the steam to carbon ratio promoted an increase in carbon monoxide and hydrogen concentrations to reveal the presence of steam reforming reactions. The work of Scenna and Gupta [4] showed active steam reforming reactions with JP8 that occurred at timescales of 750-850 ms. Figure 1 shows that the addition of steam (S/C ¼ 0-0.10) reduced the reactor temperatures from 1000 C to 755 C, while increasing the conversion from 90% to 97%, thus indicating activity in the 2.3 Dry Reforming Reactions.…”

“…In reforming, soot was primarily formed through hydrogen abstraction carbon addition (HACA) mechanism [50] (reactions R1-R2 given below), while acetylene was formed through dehydrogenation reactions [8] (reactions R3-R4 given below). In particular, steam and carbon dioxide were shown in combustion literature to suppress acetylene and soot formation [19,[51][52][53]. Soot abatement was induced through dilution and chemical interactions of the entrained carbon dioxide and steam.…”