Modification Of FCC Catalysts Prolific Diesel

In view of the present situation that diesel resources shortage, diesel in short supply overall domestic refined oil market, take a series of modification on the FCC catalyst, in order to achieve the purpose of increase production of diesel oil in the process of catalytic cracking.In this paper, based on the active principle of the FCC catalyst, take different levels of Hydrothermal, acid, rare-earth and phosphorus modification on molecular sieve, take acid treatment on kaolin clay, though XRD, BET, Pyridine adsorption ir characterization, mini FCC fluidized bed, inspect the physico-chemical property of molecular sieve like silica-alumina ratio, pore structure and acid center features, and its influence on distribution and quality of FCC production.In the experiments, handling the molecular sieve by600℃vapor, get molecular sieve with higher crystallinity, silica-alumina ratio up to10.35, at the same time produce plenty of non-framework aluminum as L acid center. With0.20mol/g oxalic acid handle the molecular sieves after hydrothermal modification will removing the non-framework aluminum in molecular sieve pore channels effectively, reduce the L acid center number of molecular sieve, and the pore volume of catalyst increased by0.03cm3/g, the specific surface area increased by17cm2/g;rare-earth modification will improve the conversion rate of catalyst reduce olefin content in gasoline effectively, when the amount of RE2O3in catalyst was3.5%(molecular sieve introduced10.0%), conversion rate increased by6.8%, diesel oil production rate reduced by3.4%, gasoline yield increased by4.1%, olefin content in gasoline reduced by6.6%, when he amount of RE2O3in catalyst higher than3.5%the selectivity of product decreased; On the basis of rare-earth modification introduce phosphorus, By the interaction between phosphorus and rare earth, the decline of diesel oil production rate will be improved, introduce1.0%phosphorus in molecular sieves, the production of diesel oil increased2.7%, conversion rate reduced by2.3%; At70℃, handling the concentration of kaolin with0.10mol·L-1hydrochloric acid for120min, the pore volume is0.03mL/g higher than the catalytic before modification, specific surface area increased15m2/g.The evaluation result of mini FCC fluidized bed showed that:compare with conventional refinery catalyst, modified prolific diesel FCC catalyst, conversion rate reduced by1.35%, he production of diesel oil increased1.81%, gasoline yield reduced by2.45%, the ratio of dieselto gasoline is0.41, coke and dry gas all have small increased. Analyse cracking gascomposition by gas chromatograph, calculated the modified catalyst hydrogen transfer index is0.11higher than contrast agent.