Experiment Study On The Effects Of Iron-based Fuel Borne Catalyst On Particulate Matter Oxidation Characteristics Of Diesel Engine

Nowadays,the major challenges of world are energy crisis and environmental pollution.Diesel engine as one of the main power machinery,its energy consumption and exhaust emissions are the hot issues.Due to PM2.5,atmospheric environment deteriorate and the visibility decrease.Diesel particulate as one of the main sources of PM2.5,emissions performance urgently needs to be optimized and improved.Fe-FBC was selected as fuel additive in this research,and the effects of Fe-FBC additive on diesel economy and conventional pollutant emission were studied.Moreover,the particle size distribution,physical and chemical properties,and oxidative activity of the particles were studied in detail.Mass ratio of iron to diesel was selected as Fe-FBC addition ratio,addition according to Fe mass fraction of 100 mg/kg,200 mg/kg,300 mg/kg and 400 mg/kg was added to pure diesel and blended fuels were named as Fe100?Fe200?Fe300 ? Fe400,separately.The effects of different proportions of fuels on fuel consumption and conventional emissions were investigated on a diesel test bench.The results shows that the fuel consumption of all FBC/diesel mixed fuels reduced,the BEMP of Fe300 and Fe400 decrease 3.3% and 3.9% at full load,especially at low load BEMP improved more obviously,decreased 12.2% and 12.1%.With the increase of load,NOx and smoke emission fueled FBC/diesel mixed fuels increased gradually.The NOx and smoke emission of Fe300 were the most effective at full load,in detail,NOx decreased 10.34%,smoke emission decreased 37.0%.The particle size distribution of the particles was studied by MOUDI and EEPS.The results shows that particles mass concentration of diesel and Fe300 were both distributed as single peak log-normal distribution,total particles mass concentration of Fe300 decreases and particle size distribution moved to the direction of accumulation mode.Meanwhile,both number concentrations were distributed as bimodal log-normal distribution.Compared to diesel,distribution of Fe300 particles moved to nuclei mode.The micro-morphology of particles was analyzed by SEM and HRTEM.The pictures shows that,compared to diesel particles,the fractal dimension decreased that indicated that the degree of agglomeration and bonding between particles was released and the structure was loose.The Fe300 primary carbon particles microcrystal layer distance and microcrystal curvature increase while microcrystal size decreases,which means degree of graphitization decreases,the degree of graphitization is weakened,which causes the carbon microcrystals to reach the lower energy stable state.The functional groups,main elements and valence state of the particles were analyzed by FT-IR and XPS.Analysis shows that the mole percent of C decreased 8.6% and the mole percent of O increased 5.08% in Fe300 particles,compared to diesel particles,and mole percent of Fe account for 3.52% of Fe300 particles.The relative content of OH in the Fe300 particles is higher than that in the diesel particles,and the relative content of C=O decrease,and the relative content of aliphatic C-H increase.The valence of Fe in Fe300 particles were +2 and +3 respectively,and the compounds are FeOOH,Fe₂?SO₄?₃,Fe2O3 and Fe₃O₄,respectively.The oxidation activities of particles were studied by TGA.There was semi-volatile organic component in Fe300 particles,its weight loss rate peak temperature was 379?.During weight loss of soot,the peak temperature of weight loss of Fe300 particles was reduced by 138 ?,compared with diesel particles.The apparent activation energy of Fe300 particles was distinctly lower than diesel particles,and the oxidation activity was improved.