摘要
以ZSM-5、USY分子筛和Al2O3为载体,分别以偏钨酸铵和磷钨酸为钨源,采用共浸渍法制备NiW加氢裂化催化剂,并以磷为改性助剂进一步对不同钨源的催化剂进行改性。使用BET,NH3-TPD,Py-IR,XRD,XPS,HRTEM等手段对催化剂进行表征,并以中低温煤焦油加氢精制后柴油馏分为原料,在固定床上考察系列催化剂的加氢裂化催化性能。结果表明:采用所制备的NiW加氢裂化催化剂对中低温煤焦油柴油馏分进行加氢改质,芳烃质量分数可降低约10百分点;与以偏钨酸铵为钨源的催化剂相比,以磷钨酸为钨源的催化剂上W和Ni硫化程度更高,因而加氢裂化活性更高,其加氢产物中总芳烃质量分数降低7.06百分点,总饱和烃质量分数提高7.10百分点;磷的加入可提高以偏钨酸铵为钨源催化剂的中强酸强度,提高B酸比例,并提高Ni和W硫化程度,进而提高其加氢裂化活性,其加氢产物中总芳烃质量分数降低7.90百分点,总饱和烃质量分数提高7.94百分点。
Ni-W hydrocracking catalysts were prepared by co-impregnation method on the carrier consisted of ZSM-5, USY zeolites and Al_2O_3 using ammonium metatungstate and phosphotungstic acid as tungsten source, respectively and then modified by phosphorus. The catalysts were characterized by BET, NH3-TPD, Py-IR, XRD, XPS and HRTEM techniques. The hydrocracking performance of the catalysts was evaluated in a fixed-bed reactor, using a hydrotreated diesel fraction obtained from middle/ low-temperature coal coking process. The catalyst using phosphotungstic acid as tungsten source exhib- its a higher sulfidation degree of W and Ni, resulting in higher hydrocracking activity. The total aromat- ics contents in the hydrocracked products are decreased by 7.06 percentage points and the total saturated hydrocarbon contents are increased by 7.10 percentage points, compared with the catalyst using ammo- nium metatungstate as tungsten source. The addition of phosphorus increases the strength of weak and moderate strong acid, improves the Br6nsted acid ratio and the sulfidation level of W and Ni of the cata- lyst prepared using ammonium tungstate as tungsten source, thus enhances its hydrocracking activity. On the P modified catalyst, the total aromatics content in the hydrocracked products was decreased by 7.90 percentage points and the total saturated hydrocarbon contents are increased by 7. 94 percentage points.
出处
《石油炼制与化工》
CAS
CSCD
北大核心
2015年第4期55-61,共7页
Petroleum Processing and Petrochemicals
基金
中国科学院战略性先导科技专项课题(XDA07020200)
关键词
偏钨酸铵
磷钨酸
P改性
加氢裂化
煤焦油
ammonium metatungstate
phosphotungstic acid
phosphorus modification
hydrocrac-king
coal tar
