One-pot Synthesis Of Cu-ZSM-35 And Its Performance In Vegetable Oil Transformation To Bio-jet Fuel

In recent years,with the rapid economic development,and the consumption of aviation kerosene is also increasing.Traditional aviation kerosene is a petroleum-based fuel,and excessive exploitation will lead to resource shortages and carbon dioxide emissions,bio-aviation kerosene prepared from substances as raw materials provides a solution to these problems.At present,the preparation process of bio-aviation kerosene generally adopts a two-step method.Due to the complex operation and high energy consumption of the two-step method,the one-step method for preparing bio-aviation kerosene from oil has received more and more attention.In this paper,the hydrothermal synthesis method was used to synthesize Cu-ZSM-35 molecular sieves with different Cu/Al ratios by adding cuprammonium complexes during the synthesis of ZSM-35 molecular sieves.SEM,XRD,Py-IR,XPS,FTIR,NH₃-TPD,XRF and N₂physisorption characterization.Using soybean oil as raw material,the performance of Cu-ZSM-35 for one-step hydrodeoxygenation/cracking isomerization to bio-aviation kerosene was investigated.The results show that:（1）To explore the influence of external factors such as Cu/Al ratio,crystallization time,template dosage and ammonia dosage on the relative crystallinity of synthesized Cu-ZSM-35zeolite during molecular sieve synthesis.It was found that when the Cu/Al ratio was 1,the crystallization time was 72 h,the amount of template agent n（CHA/Si O₂）=0.2,and the amount of ammonia water n（NH₃·H₂O/Si O₂）=0.13,the obtained Cu-ZSM-35 molecular sieves have relatively high crystallinity.（2）The effect of one-step hydrodeoxygenation/cracking isomerization of Cu-ZSM-35catalysts with different Cu/Al ratios（Cu/Al=0.5,1,1.5,2）on the performance of bio-jet kerosene was investigated.the Cu-ZSM-35 catalyst with a Cu/Al ratio of 1 has the best catalytic effect.The conversion rate of soybean oil is 75.96%,the yield of bio-aviation kerosene is 38.22%,and the product isoproportional ratio is 3.45.Using Cu-ZSM-35（Cu/Al=1）as the catalyst carrier,the reaction performance of Ni/Cu-ZSM-35 with different Ni loadings was explored.It was found that the conversion rate increased after Ni loading,but the selectivity of C₉-C₁₆of the target product decreased.And the heteroproportional ratio of the product also decreased.（3）The effects of Cu-ZSM-35（Cu/Al=1）,2%Cu O/ZSM-35 and 2%Cu/ZSM-35 three catalysts on the performance of one-step hydrodeoxygenation/cracking isomerization to bio-aviation kerosene were investigated.The study found that Cu-ZSM-35（Cu/Al=1）catalyzed soybean oil to bio-aviation kerosene better,the conversion rate increased by 18.74%,and the yield of C₉-C₁₆hydrocarbons increased by 8.22%.（4）The effect of alkali treatment modification method on the performance of Cu-ZSM-35（Cu/Al=1）one-step hydrodeoxygenation/cracking isomerization to bio-aviation kerosene was explored.It was found that the Cu-ZSM-35 catalyst after treatment with0.3mol/L Na₂CO₃solution had the best catalytic effect.The effect of reaction temperature on the catalytic performance was further investigated.It was found that when the temperature When the temperature was 390℃,the pressure was 2MPa,the space velocity was 1.4h^-1,and the hydrogen-oil ratio was 800:1,the conversion rate of the Cu-ZSM-35 catalyst treated with0.3mol/L Na₂CO₃solution is as high as 99.38%,the yield of C₉-C₁₆hydrocarbons is 60.69%.