Study On The Synergistic Effect Of Biodiesel Corrosion Inhibitor And Antioxidan

Under the background of "dual carbon",the energy structure dominated by traditional fossil fuels will gradually shift to the stage of energy utilization dominated by renewable energy.Biodiesel has attracted close attention in recent years due to its advantages of renewability and wide sources,but it has poor oxidation stability due to its corrosiveness and poor oxidation stability.The corrosiveness of biodiesel will lead to shortened service life of mechanical parts and even safety accidents,in addition,poor oxidation stability will lead to oxidative deterioration of biodiesel,and the acid compounds generated by oxidation will accelerate the corrosion of metal surfaces,hindering the large-scale application of biodiesel.Therefore,synergistic improvement of the oxidation stability and corrosiveness of biodiesel,and the synergistic mechanism of anti-oxidation-corrosion inhibition can be revealed,which can promote the commercialization and large-scale application of biodiesel and help the energy industry to transform to green and low-carbon.Based on this,a combination of corrosion inhibitor and antioxidant is used as an additive to optimize the oxidative stability and corrosivity of biodiesel.The influence law and mechanism of single corrosion inhibitor and antioxidant on oxidat ion-corrosion of biodiesel were explored,the synergistic effect law of compound ratio and concentration on corrosion inhibition and antioxidant was explored,and the simultaneous multivariate characterization method was coupled with the molecular dynamics simulation of Materials Studio to reveal the co-optimization mechanism of corrosion inhibitor-antioxidant complex paired biodiesel,and the main conclusions of this paper are as follows:(1)When the corrosion time is 240 h,the corrosion products of copp er sheets in biodiesel are mainly copper carbonate and copper oxide,and the content of methyl oleate in biodiesel is greatly reduced after corrosion,while the content of methyl palmitate and methyl linoleate increases,and the change of composition leads to an increase in the motion viscosity,frictional wear and freezing point of biodiesel,and the oxidation stability is reduced from the initial 3.76 h to 0.15 h.(2)Six reagents(antioxidants: butyl hydroxytoluene,butyl hydroxyanisole,tetraethylenepentamine,corrosion inhibitor: 2-phenylimidazoline,phenyltriazole,glycaldehyde)have antioxidant corrosion inhibition dual function,of which tetraethylenepentamine has the best antioxidant effect and 2-phenylimidazoline has the best corrosion inhibition effect.After adding 1000 ppm antioxidant/corrosion inhibitor,the corrosion level of copper sheet was reduced to 1 a required by the national standard during the corrosion period of 48 h,and the surface corrosion of copper sheet was greatl y alleviated.The oxidation induction period was increased to 6 h required by the national standard,and the oxidation stability of biodiesel was improved.The results of scanning electron microscopy showed that the copper element on the metal surface incr eased and the oxygen element decreased after the addition of antioxidant/corrosion inhibitor,indicating that the antioxidant/corrosion inhibitor could be well adsorbed on the surface of the copper sheet,blocking the further oxidation of biodiesel and the formation of acidic substances,thereby playing the effect of anti-oxygen corrosion inhibition at the same time.(3)When the compound ratio of tetraethylenepentamine and 2-phenylimidazoline is 1:1 and the addition amount is 1000 ppm,the surface of the copper sheet after 96 h of corrosion test is flat,and the surface difference from the original copper sheet is small.The copper element on the corroded surface increased from 69.6% to 85% in the blank group,which was not much different from the original copper sheet(93.3%),and the oxidation time was increased to 13.7 h.The synergistic effect of the compound antioxidant-corrosion inhibitor makes its performance better than that of a single oxidation/corrosion inhibitor,so the effect of the compound ant ioxidant-corrosion inhibitor on the oxidation stability and corrosion of biodiesel is more obvious.(4)Combined with Materials Studio molecular dynamics simulation,the corrosion inhibition effect of tetraethylenepentamine and 2-phenylimidazoline on biodiesel under three different compound ratios was simulated.The results showed that when the compound ratio was 1:1,the adsorption energy of the system was the largest,and the drug was closest to the surface of the copper sheet,and the results showed that when the compound ratio was 1:1,tetraethylenepentamine and 2-phenylimidazoline could play a good synergistic effect,and the simulation results were consistent with the experimental results.