【摘要】：多級(jí)孔結(jié)構(gòu)的ZSM-5型分子篩克服單獨(dú)微孔分子篩擴(kuò)散局限性問(wèn)題,可以提高重油等大分子對(duì)活性中心的可接近性,提高催化效率,在重油催化裂化中具有良好的應(yīng)用前景。使用有機(jī)胺模板劑合成ZSM-5分子篩是研究較多的方法,目前存在的問(wèn)題:(1)模板劑成本高、產(chǎn)率低、存在污染。(2)合成工藝復(fù)雜且產(chǎn)生介孔難以調(diào)控,易發(fā)生相分離。為解決以上問(wèn)題,利用兩親性有機(jī)硅烷和晶種輔助的方法制備多級(jí)孔ZSM-5分子篩。晶種可以誘導(dǎo)微孔的生成,有機(jī)硅烷T(mén)PHAC通過(guò)親水端與晶化體系中硅鋁凝膠或者部分溶解的晶種表面硅羥基鍵合,疏水端的烷基長(zhǎng)鏈通過(guò)自組裝作用形成的膠束引導(dǎo)介孔生成,進(jìn)而引入分子篩孔道。該體系下最佳條件進(jìn)行10 L放大合成:晶化溫度170 ℃,晶化時(shí)間18 h,模板劑用量3.12 g,水浴溫度50 ℃,攪拌速率500 r/min。產(chǎn)物的總比表面積為367.3 m2/g,介孔比表面積為110.1m2/g,總孔容為 0.312cm3/g,介孔孔容為 0.178cm3/g。利用TPHAC和TPABr雙模板合成多級(jí)孔ZSM-5分子篩。研究發(fā)現(xiàn),有機(jī)硅烷溶液中的乙醇含量影響有機(jī)硅烷臨界膠束濃度。乙醇質(zhì)量的增加,會(huì)提高TPHAC的臨界膠束濃度導(dǎo)致膠束尺寸減小,孔徑分布集中,一定程度上與模板劑具有協(xié)同作用。過(guò)量的乙醇會(huì)阻礙膠束的聚集以及與晶種的鍵合作用,導(dǎo)致TPHAC在該體系中膠束狀態(tài)的變化,TPHAC的多聚物數(shù)量增加,導(dǎo)致介孔分布不均。該體系中最佳條件:晶化溫度170 ℃,晶化時(shí)間36 h,模板劑含量6.15 g,乙醇4.15 g。產(chǎn)物的總比表面積為368.5 m2/g,介孔比表面積為106.1 m2/g,總孔容為0.367 cm3/g,微孔孔容為0.121 c·m3/g,介孔孔容為0.246 cm3/g。合成了雙功能的雙子型表面活性劑,加強(qiáng)反應(yīng)凝膠與表面活性劑的相互作用,合成出介孔分布均一的多級(jí)孔ZSM-5分子篩。該條件下總比表面積為378.5 m2/g,介孔比表面積為92.5 m2/g,總孔容為0.35 cm3/g,微孔孔容為0.11 cm3/g,介孔孔容為0.24 cm3/g。
[Abstract]:ZSM-5 molecular sieve with multilevel pore structure can overcome the limitation of single microporous molecular sieve diffusion, can improve the accessibility of heavy oil and other macromolecules to the active center, improve the catalytic efficiency, and have a good application prospect in heavy oil catalytic cracking. The synthesis of ZSM-5 molecular sieve by using organic amine template is a lot of research methods. The existing problems are as follows: (1) the cost of template is high, the yield is low, and there is pollution. (2) the synthesis process is complex and the mesoporous is difficult to control. It is easy to separate phases. In order to solve the above problems, the multiporous ZSM-5 molecular sieve was prepared by using amphiphilic organosilane and crystal seed assisted method. The formation of micropores can be induced by seed. Organosilane TPHAC is formed by bonding silica hydroxyl group on the surface of silica aluminum gel or partially dissolved seed by hydrophilic end, and the long alkyl chain of hydrophobic end leads to the formation of mesoporous pores by micelles formed by self-assembly. Then the molecular sieve channel was introduced. The optimum conditions were as follows: crystallization temperature 170 鈩，

本文編號(hào)：2391724