Synthesis Of ZSM-35 Zeolites And Its Application In Propylene Hydration To Isopropanol And Biomass Hydrocracking To Aviation Kerosene

Zeolite ZSM-35 is a kind of artificial high-silicon zeolite with FER?ferrierite?topology.It has suitable acid amount and acid strength,good hydrothermal stability,shape selective catalytic ability and anti-carbon deposition ability.It was found in the experiment that the modified H-ZSM-35 catalyst has high catalytic activity,excellent selectivity and stability in the reaction of propylene hydration to isopropanol and biomass deoxidized oil?mainly n-hexadecane and n-octadecane?hydrocracking to produce biological aviation kerosene.In this dissertation,ZSM-35 were synthesized by hydrothermal synthesis using cyclohexylamine as the template.The synthesis conditions and influencing factors of the ZSM-35 were systematically investigated,and a synthetic system of ZSM-35 suitable for further enlarge was developed.Based on the optimized synthesis conditions,the synthesis of ZSM-35 was enlarged in futher scale.The ZSM-35 obtained by scale-up synthesis was subjected to ammonium exchange,alkali treatment,ion exchange,phosphorus loading and other series of modifications to prepare catalysts such as H-ZSM-35,M-ZSM-35,and P/H-ZSM-35.For the evaluation of its catalytic performance in the reaction of propylene hydration to isopropanol and the selective hydrocracking of biomass deoxidized oil to produce biological aviation kerosene.The results are shown as follows:Under static hydrothermal conditions,the ZSM-35 zeolite with high crystallinity was prepared under the condition that the silica-alumina ratio SiO₂/Al₂O₃ is 20⁶0,the crystallization time is more than 48 h,the seed addition amount is 1²%?measured by the mass of SiO₂?,pseudo-boehmite,Al₂?SO₄?₃·18H₂O,NaAlO₂ as the aluminum source.Under the optimized synthesis and stirring conditions,the ZSM-35 with high crystallinity and uniform crystal grains can be synthesized and synthesized in a 50L autoclave,and the product yield is 83.3%.The ZSM-35 obtained by scale-up synthesis was subjected to ammonium exchange modification at different concentrations,and the Na⁺content in the exchanged H-ZSM-35catalyst was measured by ICP,and the catalytic performance was evaluated by propylene hydration reaction.The optimaized ammonium exchange concentration was 0.4 mol·L^-1.The reaction of propylene hydration to isopropanol was carried out with H-ZSM-35 as catalyst.The optimaized reaction conditions are as follows:reaction temperature is 180°C,reaction pressure was 3.5 MPa,and the molar ratio of propylene to water is 1:0.75.Under this reaction condition,the single-pass conversion of propylene was 4.44%,the yield of isopropanol in the product was 20.60%,and the selectivity of isopropanol was 98.76%.A suitable concentration of alkali treatment can eliminate the mixed crystals and amorphous substances generated during the synthesis of ZSM-35,increase the catalytic activity of H-ZSM-35 in the hydration of propylene.The optimized alkali concentration is 0.2mol·L^-1.Then,the single-pass conversion of propylene was 5.16%,the selectivity of the isopropanol was 99.24%,and the content of isopropanol in the product was 22.74%.Through the metal ion exchange of ZSM-35,it was found that the catalytic activity of the M-ZSM-35 catalyst after metal ion modification is related to the polarizability of the corresponding metal ion,and the larger the ion polarizability,the higher catalytic.Among them,the Zr-ZSM-35 catalyst after Zr?NO₃?₄ solution exchange has the best performance and good stability.Compared to other microporous zeolite catalysts in the biohydrocracking of Bio-oil to selectively produce bio-aviation kerosene,such as H-ZSM-5,H-ZSM-22,H-MCM-49,HY,H-?,the H-ZSM-35 catalyst has high cracking activity and selectivity and is suitable as a catalyst for the hydrocracking reaction of Bio-oil.Ammonium exchange modification can improve the catalytic activity of ZSM-35catalyst in the hydrocracking of biomass deoxidation oil.The conversion of biomass deoxidation oil?Bio-oil?is increased from 66.48%to 92.92%,and the selectivity of target product(C₉^C₁₅)is 57.63%,the yield increased from 22.50%to 41.86%.The H-ZSM-35 catalyst prepared after alkali treatment with appropriate concentration of NaOH can improve the selectivity of dehydrogenation of biomass for hydrocracking.The optimum alkali concentration is 0.2 mol·L^-1.The conversion rate of Bio-oil was 89.50%,and the selectivity of the target product(C₉^C₁₅)increased from 57.63%to 62.49%,and the yield was 43.32%.The loading of a certain amount of P on H-ZSM-35 catalyst can significantly increase the selectivity of hydrocracking of Bio-oil.The optimized loading is 1%,and the selectivity of target product(C₉^C₁₅)can reach 70.06%.The conversion of Bio-oil was 71.44%,and the yield of the target product(C₉^C₁₅)was 35.18%.H-ZSM-35 catalyst in the hydrocracking of Bio-oil with solvent,the preferred reaction temperature is 320°C,the WHSV is 1 h^-1,and the ratio of hydrogen to oil is 900.Under this reaction condition,the conversion of Bio-oil is 88.66%,the selectivity of target product(C₉^C₁₅)is 64.56%,and the yield is 43.85%.For concentrated Bio-oil,the preferred reaction temperature is 340°C,and the ratio of hydrogen to oil is 600⁹00.The reaction remained stable for 151 h,the conversion rate of biomass alkanes was about 36%,the selectivity of the target product(C₉^C₁₅)was stable at about 76%,the yield was stable at about 24.5%.