γ-Al2O3作为催化剂载体在炼油领域具有广泛应用。随着原油资源的重、劣质化,重油加工过程,如固定床渣油加氢、重油催化裂化,对其催化剂载体均提出了大孔要求以满足重油大分子在催化剂孔道内的传质扩散所需,因此,制备适用于重油加工的大孔γ?Al2O3载体受到越来越多的关注。γ?Al2O3性质主要决定于其前驱物拟薄水铝石,本工作综述了大孔拟薄水铝石的主要工业制备工艺,包括沉淀法、醇铝水解法等,并介绍了基于上述工艺所进行的γ?Al2O3载体扩孔研究,如pH摆动扩孔、添加扩孔剂扩孔及水热处理扩孔等。最后,展望了今后大孔拟薄水铝石和γ?Al2O3载体制备研究的重点和发展方向。
γ?Al2O3 is widely used as catalyst carrier in petroleum processing realm, owing to its porosity, high dispersibility, adjustable surface acid/base characteristics, attractive mechanical properties and good thermal stability. As the quality of crude oil is increasingly heavy and inferior, more and more attention has been paid on the preparation of macro-mesostructured γ?Al2O3 since the γ?Al2O3 as the catalysts carrier, that used in the heavy oil processing, such as fixed-bed residue hydrotreating or RFCC, need more meso-and macroporous structures to reduce the internal diffusion resistance of large molecules and improve the catalytic activity. Commonly, pseudoboehmite as the raw materials turns decisive significance for the physiochemical properties of γ?Al2O3. For instance, the pore properties of γ?Al2O3 are greatly in?uenced by the size and morphology of pseudoboehmite crystallites and their aggregation. This manuscript thus reviewed the representative preparation methods of pseudoboehmite including precipitation method and aluminium alkoxide hydrolysis method. The advances of Al2(SO4)3?NaAlO2 method and carbonization method, as two main industrial technologies, were emphatically introduced. New reactors and technologies for the precipitation were developed in order to provide su?cient mixing intensity and recirculation of different reactants, which could bring about a homogeneous supersaturation distribution in the instantaneous neutralization reaction, and then lead to uniform crystallites size, thereby pseudoboehmite with large pore volume and narrow pore size distribution. Besides, the relative meso??and macroporous structures control technologies were also highlighted, such as pH swing method, pore-enlarging additives method, and hydrothermal treatment method, etc. The advantages and disadvantages of these methods were also briefly analyzed. At last, the development trend was introduced and some suggestions were proposed.