Study On The Performance Of Diesel Engine Fueled With N-Pentanol/Fishcher-Tropsch Diesel Blended Fuel

With the gradual depletion of traditional energy and the growing air pollution,it is urgent to develop clean alternative fuels.In view of the special national condition that coal resource reserve is abundant in our country,vigorously develop of coal-to-liquids technology has become a very promising direction.The F-T diesel made by indirect coal liquefaction technology has a high cetane number,almost contains no aromatic hydrocarbons,has sufficient combustion and low emission pollution.Alcohol fuels can effectively reduce the soot emissions of diesel engines due to their own oxygen content.Compared with methanol,ethanol and other low-carbon alcohols,n-pentanol provides better miscibility with F-T diesel and the addition of n-pentanol to F-T diesel can further reduce the emission of soot.In this paper,F-T diesel is used as the basic fuel.By adding n-pentanol to F-T diesel with volume ratio of 5%,10% and 20%,three kinds of n-pentanol/F-T diesel blends are created and they are classified as PE5?PE10 and PE20 respectively.0# diesel is set as contrast fuel.The physical and chemical characteristics,economic characteristics and emission characteristics as well as micro characteristics,graphitization characteristics,oxidation characteristics and surface oxygen functional group of the emission particles of 0# diesel,F-T diesel,PE5,PE10 and PE20 five fuels are studied.Specific research is as follows:A miscibility experiment of n-pentanol/F-T diesel is carried out.The result shows that PE5,PE10 and PE20 have not shown obvious stratification at room temperature for 30 days,which indicates that n-pentanol and F-T diesel have good mutual solubility.The physical and chemical characteristics of 0# diesel,F-T diesel,PE5,PE10 and PE20 test fuels are obtained by measuring and combining with empirical formulas.The fuel consumption and conventional emission of diesel engine fueled with 0#diesel,F-T diesel,PE5,PE10 and PE20 are measured by building a 186 FA diesel engine bench.The result shows that the equivalent fuel consumption and CO,HC,NOX and soot emissions of F-T diesel are lower than that of 0# diesel.Fuel consumption reduces by3.6% with 10% load at engine speed of 3600r/min and the reduction of CO,HC,NOX and soot emissions is 48.1%,76.9%,33.0% and 27.3% respectively at rated condition.Compared with F-T diesel,the equivalent fuel consumption of the n-pentanol/F-T diesel blends increases with the increase of n-pentanol blending ratio;CO emissions increase at small load and decrease at full load,HC emissions increase;Soot emissions decrease.The NOX emissions of n-pentanol/F-T diesel blends are lower than the F-T diesel at all operating points.Analysis of Soluble Organic Fractions(SOF)on the surface of particles is carried out by Gas Chromatography-Mass Spectrometry(GC-MS).The result shows that the SOF mass fraction of F-T diesel particle is smaller than that of 0# diesel particle,the mass fraction of alkane,aromatic hydrocarbon,acid and ester in SOF decreases and low carbon atoms increase but high carbon atoms decrease.Compared with F-T diesel particle,with the increase of n-pentanol blending ratio,SOF mass fraction of particle gradually increases,the mass fraction of aromatic hydrocarbon in SOF decreases,while the mass fraction of alkane,acid and ester increases,and low carbon atoms increase but high carbon atoms decrease.The morphological characteristic,oxidation characteristic and graphitization degree of particles are studied by scanning electron microscopy(SEM),thermogravimetric analyzer(TGA)and laser Raman spectrometer(LRS).The result shows that the size of F-T diesel particle is smaller than that of 0# diesel,and the particle size decreases gradually with the increase of n-pentanol blending ratio.The mass fraction of SOF of F-T diesel,PE5,PE10 and PE20 particles is 17.5%,20.4%,22.6% and 25.2% respectively,and the peak temperature of weight loss rate of dry soot is 617?,608?,601? and 567?respectively.Graphitization degree of particle from strong to weak is F-T diesel>PE5>PE10>PE20>0# diesel,and the larger the load,the larger the IG/ID value of the five kinds particle is.X-ray photoelectron spectroscopy(XPS)is used to analyze the oxygen-containing functional groups and the hybrid form of carbon atoms on the surface of particles.The result shows that the O/C ratio of the particle from big to small is 0# diesel> PE20>PE10> PE5> F-T diesel,and as the load increases,the O/C ratio of the five fuel particles decreases.The relative content of hydroxyl functional group(C-OH)is 7.25%~9.85% andthe relative content of carbonyl functional group(C=O)is 2.01%~4.56% on the surface of particles of the five fuels,the hydroxyl functional group is obviously more than carbonyl functional group.The relative content of the two oxygen-containing functional groups from high to low is 0# diesel>PE20>PE10>PE5>F-T diesel.The oxygen-containing functional groups of the five fuel particles reduce with the increase of the load.The sp3/sp2 ratio of the five fuel particles from large to small is 0# diesel>PE20>PE10>PE5>F-T diesel,and the sp3/sp2 ratio of the five fuel particles decreases with the increase of load.