Research On The Effect Of Oxidation Degree Of Biodiesel On Its Combustion Characteristics

The oxidative stability and combustion characteristics of biodiesel have been the focus of research.The Rancimat method is used to accelerate the oxidation of biodiesel,study the oxidation characteristics of biodiesel,and use a self-designed burner and OH-PLIF system to form a combustion test platform.The effect of the degree of oxidation of biodiesel on its combustion characteristics,feedback on the application and storage of biodiesel.This paper mainly studies from the following perspectives.Firstly,the jatropha biodiesel was oxidized to analyze the rate and trend of the physicochemical properties of biodiesel caused by accelerated oxidation.The results showed that the composition of Jatropha biodiesel changed greatly during oxidation.Methyl linoleate contains multiple bisallyl sites which are sensitive to oxidation and are easily oxidized.There will be aldehyde,ketone and molecular weight during oxidation.Higher oxygenates and soluble polymers were formed;at the same time,the density of Jatropha biodiesel increased from 0.862g/cm³ to 0.895g/cm³,and the surface tension increased from 28.85mN/m to 31.42mN/m.The kinematic viscosity was5.73mm²/s increased to 7.67mm²/s?25??,the acid value increased from 0.36mgKOH/g to 2.02mgKOH/g,cetane number increased from 53.35min to 56.65min,the heating value gradually decreased;short-time oxidation The peroxide will stimulate the decomposition of the fatty acid chain and destroy the stability of the lubricating adsorption film;long-term oxidation will form highly polar products and epoxy compounds,which will help to form a stable boundary film on the metal surface and improve the lubrication of biodiesel.performance.Secondly,the OH-PLIF system was used to study the flame characteristics of Jatropha biodiesel with different oxidation degrees,including flame OH-PLIF total signal intensity,flame front area,flame propagation speed and fuel consumption rate.The flame front area decreases first and then increases with the increase of the equivalence ratio.With the deepening of oxidation,the total signal intensity of flame OH-PLIF of Jatropha biodiesel increased gradually from 1.58×10⁶ to 3.91×10⁶??=1.0?,the flame front area gradually decreased,and after 12 hours of oxidation,the flame front area It decreased to 0.32cm²/s??=1.0?;the laminar flame propagation velocity of Jatropha biodiesel showed a trend of increasing first and then decreasing with the change of equivalence ratio.With the increase of oxidation time,the flame propagation speed of biodiesel increased from 12.859cm/s to 61.25cm/s??=1.0?,and the fuel consumption rate increased first and then decreased.Finally,the combustion characteristics of biodiesel with different oxidation degrees were studied.With the increase of biodiesel oxidation time,the CO₂ emission from combustion increased first and then decreased,and CO showed the opposite trend.In different oxidation time,Jatropha biosynthesis The NO emission of diesel oil gradually decreases with the increase of equivalence ratio.At the same time,with the increase of oxidation time,the NO emission from biodiesel combustion increases with the increase of oxidation time.The maximum NO emission is 48ppm and the lowest is14ppm..