Combustion characteristics of soot deposits from diesel engines

• The purpose of this study was to investigate the combustion characteristics of soot deposits from diesel-powered engines. The soot deposits were collected in the exhaust stream from diesel engines at Volvo Truck Corporation in Gothenburg, Sweden. The combustion experiments were performed in a flow reactor in the presence of 2–10% O2 and 0 or 7% H2O. The temperature was increased at a rate of 10°C/min and the production rates of CO and CO2 were determined. The surface area of the soot deposits increased as the soot was heated in an inert gas stream. Combustion rates increased rapidly at temperatures above 400°C. Kinetic studies indicated that the reaction between oxygen and the carbon in diesel soot could be described by Langmuir-Hinshelwood kinetics in the absence of water vapour. The soot deposits were combusted more effectively when water vapour was present in the gas mixture. The selectivity for production of CO was constant in the absence of water vapour but followed the temperature dependence of the water-gas shift reaction in the presence of water vapour. Ignition temperatures of the soot deposits decreased as the oxygen content in the gas mixture increased. When water vapour was present, the soot deposits ignited at even lower temperatures. This study shows that diesel deposits can only be combusted at relatively high temperatures in the absence of a combustion catalyst.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

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