| The consumption of petroleum-based fossil energy is accompanied by the depletion of resources and the emission of a large number of greenhouse gases.One way to solve the"dual carbon"problem is to use biomass energy.Making jet fuel from biomass is one of the research hotspots.In this paper,pure-silica ZSM-22 and Y/ZSM-22 composite zeolite were synthesized by hydrothermal synthesis method in alkali metal ion free system,which were used to produce bio-jet fuel by one-step hydrogenation of bio-oils.ZSM-22 zeolite with SiO2/Al2O3 ratio of 90 was synthesized in conventional system for hydrocracking/isomerization of biological deoxygenated oil to produce bio-jet fuel.The synthesized samples were characterized by XRD,SEM,NH3-TPD and N2-adsorption.The reaction properties of the catalysts prepared by different systems were investigated using soybean oil and long-chain n-alkanes as raw materials,respectively.The results show that:（1）Pure-silica ZSM-22 zeolite was synthesized in alkali metal ion free system with n-butylamine（BA）as template.The relative crystallinity was up to 163%.With the increase of n-butylamine dosage,the grain size of the sample decreased gradually.The grain length is about 5μm.The Y/ZSM-22 composite molecular sieve was synthesized by adding zeolite Y into the synthetic system.Compared with the Pure-silica ZSM-22 molecular sieve,the strong acid content of the composite molecular sieve was significantly higher,and the specific surface area was up to 174 m2/g.（2）The alkali-treated ZSM-22 Pure-silica sample synthesized by alkali metal ion free system was loaded with Cu for one-step hydrogenation of bio-oils to jet fuel.It was found that the activity and jet fuel yield of the catalyst sample prepared by alkali-treated Pure-silica ZSM-22 were higher than those prepared by non-alkali-treated ZSM-22.The soybean oil conversion rate was 96.84%.The yield of jet fuel was 59.85%and isomerism oil was 43.53%.When Y/ZSM-22 composite molecular sieve was loaded with Cu,the conversion rate of soybean oil was 95.62%,the yield of jet fuel was 62.48%,and the yield of isomerized oil was48.04%.（3）The effect of Na OH replacing KOH on the synthesis of ZSM-22 molecular sieve with SiO2/Al2O3 ratio of 90 was investigated in conventional synthesis system.It was found that pure phase ZSM-22 could be synthesized with the substitution ratio of 0～60%,and the amplified synthesis of samples with KOH as alkali source and Na OH substituted 40%KOH as alkali source was carried out.The results showed that the synthesis process had good stability and repeatability.The synthesized mother liquor was recycled,and it was found that the pure phase ZSM-22 molecular sieve could be obtained after the mother liquor was recycled for three times.（4）Biological deoxygenated oil hydrocracking/isomerization performance evaluation results show that with KOH as alkali source synthesis of ZSM-22 samples after alkali treatment can improve the activity of catalysts and the efficiency of jet fuel,after alkali treatment of the sample after passivation and phosphating,the yield of jet fuel has increased.The conversion rate of long-chain n-alkanes and the yield of jet fuel were 96.66%and 53.85%,respectively,for the Pt/ZSM-22 catalyst prepared by alkali treatment.The Pt/ZSM-22prepared by alkali treatment and passivation and phosphating of ZSM-22 has the highest fuel yield of 55.91%. |
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