Study On Performance Of Mg-Al Solid Base Catalyzed Oil Cracking

With the vigorous development of agriculture in our country,the output of biomass has been increasing continuously,and how to use these biomass energy reasonably has become a research hotspot in recent years.Biomass energy is a kind of clean green energy.It not only produces huge output,but also has little environmental pollution,low price,and huge energy content.It is expected to become an alternative energy source to alleviate the crisis of fossil energy.Bio-oil has great potential as a research material energy to replace fossil energy,especially the bio-based hydrocarbon fuel prepared by catalytic cracking oil can directly replace fossil fuel combustion.In this paper,the preparation of Mg-Al solid base catalyst and the experimental research on catalytic oil cracking are carried out.On this basis,three modified catalysts,KF/Mg-Al,Nd Mg Al and Ce Mg Al,are prepared and the catalytic oil cracking test the specific research contents are as follows:（1）The experimental study of catalytic oil cracking with Mg-Al solid base as catalyst,the temperature of catalytic cracking,t he ratio of magnesium and aluminum,the particle size of catalyst and the number of times of catalyst reuse on the yield,acid value and saponification value of liquid products were investigated,density and catalyst coking rate.The test determined that t he optimum temperature for Mg-Al solid base catalyzed oil cracking is 470℃;the optimum ratio of magnesium to aluminum in the catalyst is 3:1;the optimum particle size of the catalyst is 3-4 mm;the catalyst has good reusability.Under the optimal conditions,the yield of the liquid product was 58.10%,the acid value of the liquid product was 1.1 mg（KOH）·g^-1,the saponification value of the liquid product was 9.3 mg（KOH）·g^-1,the density of the catalyst is 0.7652 g·cm^-3,and the coking rate of the catalyst is 10.40%.The main components of the liquid product obtained under the optimum conditions are alkanes and olefins,followed by aromatic hydrocarbons and alcohols,and the total content of hydrocarbons is 83.19%.（2）The Mg-Al solid base catalyst was modified with KF,and the influence of KF quality score and repeated use times on the yield,acid value,saponification value,density and catalyst coking rate of the liquid product was investigated.The optimum quality score of KF was determined to be 20%,and the catalyst under this condition was used for the catalytic cracking of oil.The yield of the liquid product was 54.62%,and the acid value of the liquid product was 0.5 mg（KOH）·g^-1,the saponification value of the liquid product is 4.7 mg（KOH）·g^-1,the density of the liquid product is0.7764 g·cm^-3,the coking rate of the catalyst is 12.45%,and the catalyst has good reusability.The main components of the liquid product under optimal conditions are alkanes and alkenes,followed by aromatic hydrocarbo ns and alcohols,and the total content of hydrocarbons is 85.33%.Finally,the reaction mechanism was explored according to the composition of the liquid product.（3）The Mg-Al solid base catalyst was modified with two rare earth metals,and two kinds of catalysts,Nd Mg Al catalyst and Ce Mg Al catalyst,were prepared.The optimal ratio of Nd Mg Al catalyst is Nd³⁺:Mg²⁺:Al³⁺=0.75:3:1 and the catalyst was used for the experimental study of catalytic oil cracking.The yield of the collected liquid product was 57.82%,and the acid value of the liquid product was 0.9mg（KOH）·g^-1,the saponification value is 5.5 mg（KOH）·g^-1,the density is 0.7965g·cm^-3,the coking rate of the catalyst is 14.06%,the main components of the liquid product are alkanes and olefins,follo wed by aromatic hydrocarbons and alcohols,and the total content of hydrocarbons is 78.39%;the optimal ratio of Ce Mg Al catalyst is Ce³⁺:Mg²⁺:Al³⁺=0.5:3:1,the catalyst under this condition is used for catalysis In the oil cracking test,the yield of the o btained liquid product was 56.52%,the acid value was 1.1 mg（KOH）·g^-1,the saponification value was 4.4 mg（KOH）·g^-1,and the density was 0.7842 g·cm^-3.The coking rate of the catalyst was 15.22%,the main components of the liquid product are alkanes and ole fins,followed by aromatic hydrocarbons and alcohols,and the total content of hydrocarbons is 82.52%.By evaluating the catalytic performance of the four catalysts and analyzing the composition of the liquid products,the results show that the catalytic a ctivities of the modified catalysts are enhanced,the content of hydrocarbons in the components of the liquid products is higher,and the cracking degree of the oil is higher.deepen.Among them,the KF/Mg-Al solid base catalyst has relatively strong catal ytic activity,the content of hydrocarbons in the liquid product is the highest,and the effect of catalytic oil cracking is better.The results of this study can provide a theoretical basis for the research and application of Mg-Al solid base catalyzed oil cracking to prepare bio-based hydrocarbon fuels.