Combustion Spectrum Analysis And Reaction Process Of Chlorella Biodiesel

In the context of increasing energy shortages,renewable energy is beginning to be favored by countries around the world.Biodiesel,as a kind of renewable energy,has the advantages of good power and economy.Compared with traditional petroleum,its combustion process can greatly reduce the emission of soot.This paper mainly focuses on the spectral analysis of free radical distribution during the combustion process of Chlorella biodiesel,the establishment of a detailed mechanism model of combustion reaction kinetics and its simplification,which provides a theoretical basis for studying the combustion characteristics of Chlorella biodiesel.Chlorella biodiesel was prepared by hydrothermal liquefaction method and subjected to combustion experiment.A micro-spectrometer manufactured by Shanghai Fuxiang Optical Co.,Ltd.was used to measure the spectrum,obtain the free distribution during the combustion process and analyze its generation principle.Studies have shown that in the ultraviolet-visible band（200-600 nm）,there are multiple free radicals such as OH,NH,CN,CH,_C2,among which new free radical,NH group,is found in the chlorella biodiesel flame spectrum at a wavelength near 335 nm and the characteristics are obvious;in the visible-near infrared band（600～1 100 nm）,there are a small amount of free radicals such as H₂O molecules and OH,C₂.GCMS（Gas Chromatography-Mass Spectrometer）was used to extract the types of Chlorella biodiesel and their percentage;the density and viscosity were measured by experimental instruments such as densitometer and viscometer;the physical property parameters were brought to experienced formula,and the following results are obtained:The main components of chlorella biodiesel include methyl linoleate,methyl linolenate,methyl palmitate,9,-methyl nineteen Methyl alkanoate,methyl oleate and methyl heptadecanoate,of which methyl linoleate,methyl linolenate and methyl palmitate are the main ones.The physical and chemical properties are as follows:density is 0.864,cetane value is 52,sulfur content is 0,calorific value is 38.67,and ester content（mass fraction）is 96.7.The reaction path analysis method and temperature sensitivity analysis method are combined to simplify the detailed mechanism.The simplified mechanism includes 114reactants and 312 elementary reactions.The simplified mechanism is used to predict the ignition delay time,and the results of the simulation calculations are compared with the results predicted by the detailed mechanism model.The results show that the simplified mechanism and the detailed mechanism have similar delay times,and the relative errors between them are 1.6%,0.6%,1.4%,therefore,the simplified mechanism can not only improve the calculation efficiency,but also maintain good accuracy.The simplified mechanism is analyzed to simulate the transfer path of N element in the combustion process.In the transfer process of N element,the N₂ in the air is converted into NO or NO₂ through the rapid type and the thermal type and discharged into the atmosphere.During this transfer process,free radicals CN and NH are generated.Their residence time is shorter,so the emitted spectrum is relatively weak,which also verifies that there are weak peaks of CN and NH free radicals in the chlorella biodiesel combustion experiment spectrum.