Improvement Of Ultrastable Y Zeolite

While crude oil is heavy-oriented and market demand of heavy fuel decreases, the ratio of resid blended feedstock increases continuously, and resid catalytic cracking technology also develops rapidly. Meanwhile, the deepening strict of national environmental requirements and the increasing demand of clean fuel also brings new challenges to the development of refinery industry. For the purpose of adapting to this requirement, better performances of catalytic cracking catalyst are needed.Ultrastable Y zeolite is the major active components of catalytic cracking catalyst, and its modification process can produce some key effects on the ability of resid cracking, hydrothermal stability, and product selectivity of catalyst.Some novel technologies have, been employed for the production of ultrastable Y zeolite in my plant in recent years. In the second filtration step, ion-exchange and scrubbing of zeolite are carried out with a belt filter instead of the traditional plate-and-frame filter press, so that the production process is simplified, the continuous production is implemented, and the yield and utilization ratio of raw materials are improved. The technology of spray drying is adopted in zeolite drying step, which has the following advantages: firstly, heat transfer is improved to obtain a faster drying rate, a higher efficiency of equipment and a stable solid content of the output materials; secondly, the energy efficiency is improved through the utilization of roasting furnace exhaust as heat resources. However, these novel technologies also resulted in two main problems: one was that the rate of the second filtration, exchange and scrubbing in the belt filter was slow, and the Na₂O content in zeolite was not stable: the other is that the cell constants did not contract and the particle size of zeolite was bigger in spray drying. In combination with the research of zeolite synthesis and modification, this subject elaborates the effects of ultrastable Y zelolite on performance of catalytic cracking catalyst. Based on the mechanism of filtration and spray drying process, this work proposed some improvements, by experiments in combination with the work of zeolite synthesis and modification, explored the influences of the improvements on production and quality, and made the new technologies implemented successfully in the production.