| As an alternative energy,bio-based fuel will be used in diesel engines,it is of great significance for alleviating petroleum energy crisis.There is a significant effect on reduction of soot,carbon monoxide and other emissions;Control of nitrogen oxides(NO)emissions is always a key and difficult problem.Based on the analysis of components,characteristic fuel was constructed.The effects of component characteristics and components formation on NO emission of bio-based fuel oil were studied by chemical kinetics calculation and testing.The conclusion of this paper will provide theoretical and experimental basis for reducing NO emission in the application process of bio-based fuel.There is an important reference for studying on NO emission characteristics of similar biofuels.The main research contents and conclusions are as follows:1.The alternative components of soybean bio-based fuel by rapid pyrolysis were studied.The model of the SPBF alternative fuel was constructed.By GC-MS analysis,We concluded that the content of short-chain fatty acid methyl ester increased,the proportion of unsaturated components decreased,they were typical compositional characteristics of bio-based fuels comparing to biodiesel.Five alternative components of bio-based fuel were identified.They were methyl decanoate(MD),Methyl-9(5)-Decenoate(MD9D or MD5D),methyl octanoate(MO)and n-heptane.Two types of special fuel with significant unsaturation and significant short carbon chain characteristics respectively were constructed.They were named MD blend A and MD blend B respectively.Based on oxygen-based and unsaturated characteristics of bio-based fuels,characteristical fuel of bio-based fuel was constructed.It was named MD blend C.2.The simulation study of NO emission characteristics of SPBF substitute components and characteristic oils was carried out.It was verified that the alternative fuel model has a good alternative to SPBF in NO generation.Based on zero-dimensional closed homogeneous combustion model,the temperature and equivalence ratio can be varied,Comparative study was carried out betwen saturated components(MD)and unsaturated components(MD9D),and between MD blend A and MD blend B.Variation of combustion delay of various components and characteristic blending Oil was studied.The conclusion can be used as the theoretical foundation for the construction of bio-based fuel combustion mechanism,It was MD blend C.Based on the internal combustion engine(HCCI)model,MD blend C as a more appropriate alternative fuels for bio-fuels was verified in terms of NO generation and ignition delay.3.Experimental study of single-component and multi-component blends of biomass fuel were carried out.It provides data support for characteristics analysis of SPBF's diesel engine emission.According to the characteristics of bio-based fuel component,Test oil was selected,they were Short chain components(MO),Saturated long chain component(methyl palmitate),unsaturated component(Methyl oleate)and 0~#GB?diesel.They corresponded to the alternate components.In accordance with the principle of the same oxygen content,two types of special fuel with significant unsaturation and significant short carbon chain characteristics respectively were constructed.they were CBD-2 and CBD-3.Biomass components are evenly blended,it was CBD-1.the effect of molecular structural differences on NO emission were quantified by the experimental data.Some components in CBD-1 inhibited the rate of combustion chemical reaction and the thermal efficiency.Under low load,biomass components can reduce NO emissions,and under heavy load,NO increased significantly.The test result further proved that there was no obvious linear relationship between NO generation and blending ratio.4.Engine bench test of SPBFwas carried out to verify the effectiveness of the SPBF alternative fuel constructed in this paper.The results showed that NO emission reduction in turn was B10,B20,B30;at 100%load.When more than 2000rpm,NOx emissions increased,from less to more in order were B10,B30,B20.The change rule of NO concentration of the blend oil and the bio-based fuel was consistent,which also showed that the technology of component blending was feasible. |
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