Both Fisher-Tropsch (F-T) diesel and methanol can be made from coal, which can be called coal-based fuels. The use of coal-based fuels can increase coal utilization and promote the diversified development of diesel fuel. The tests fuel used in the study was mixtures of F-T diesel and methanol in different proportions, where the volume fraction of methanol was 0%, 5%, 10% and 15%, respectively. In order to study the nanostructure and oxidation reactivity of particulate matters in diesel engines using these four coal-based fuels, exhaust particles of diesel engines were collected under calibration conditions, and the particulate samples were analyzed by high-resolution transmission electron microscopy (HRTEM) and thermogravimetric analyzer (TGA). The results showed that exhaust particulate matters had shorter fringe length (La), wider separation distance (d), and larger fringe tortuosity (Tf) with the increase of methanol volume ratio. It was also found out that the addition of methanol increased the amount of soluble organic matter on the surface of the particles, and decreased the temperature of the particles burning at the maximum weight loss rate, the temperature at which the particles is completely oxidized and the apparent reactive energy (Ea) of the particles. The blending of methanol reduced the graphitization degree, increased the disorder degree of the particulate matter, and contributed to the oxidation of particles. These results illustrated that the use of methanol have great influence on the physical and chemical properties of the exhaust particulate matter, which will be significant for the improvement of diesel engine aftertreatment technology.
 

diesel engine, coal-based fuels, exhaust particulate matter, nanostructure, oxidative Reactivity