Manufacturing of low-pour-point fuels using high-silica zeolite catalysts

The results of research and development study on a dewaxing catalyst: improvement in the technology of synthesis of the zeolite component, selection of promotion conditions, and the development of technology for production and use of the catalyst, are presented. It has been found that the hydrothermal treatment of silica gel for 12–24 h at a temperature of 100–120°C leads to the formation of pores of a 100–200 Å radius. Use of the treated silica gel and temperature elevation from 130 to 170°C leads to reduction of the crystallization time from 120 to 48 h and the formation of high-silica zeolite with a particle size of 1–6 µm 3 . The zeolite promoted with zinc by ion exchange exhibits a higher dewaxing activity than its zinc-promoted samples prepared by impregnating or batch mixing. Furthermore, the introduction of a second promoter (phosphorus compound) into the catalyst reduces the dewaxing temperature by 45°C relative to the initial sample. On the basis of these data, the catalyst production technology as applied to the equipment of the Angarsk plant has been worked out. The designed catalyst DEP-1 in combined use with the hydrotreating catalyst AGKD-400 provides the manufacture of diesel fuel base stock with a cloud point of −38°C, a cold filter plugging point of −41°C (for class 3 diesel), type III according to GOST R 52368-2005 (EN 590: 2009).