AM-97-11 NEW FCC PARTICULATE ABATEMENT TECHNOLOGY

Description:

The FCCU third stage separator (TSS) is a vessel containing multiple cyclones located downstream of the regenerator for the purpose of removing catalyst particles entrained in the flue gas. During the 1970’s TSS units became widely used to remove catalyst particles larger than 10 microns from flue gas in order to protect power recovery expander blades from excessive erosion. In more recent years TSS units were developed to achieve high removal efficiency for particles less than 10 microns. These designs have been installed to meet stringent environmental regulations of particulate levels in flue gas in ranges of 50 - 100 mg/Nm3. A TSS that can remove the fine dust with a high efficiency and meet environmental, regulations is signifcantly lower in cost compared to the two alternatives of Wet Gas Scrubbing and Electrostatic Precipitators. There are several different TSS designs in use today. The most important process parameter of the TSS is the particle or dust collection efficiency. Other important process parameters include the pressure drop across the TSS and the amount of gas underflow used to remove collected dust from the TSS. This paper is focused on the TSS particle collection efficiency. In the early 1990’s Mobil installed three “high efficiency” TSS units on three different FCC units to meet flue gas environmental regulations of 50 mg/Nm3 and 100 mg/Nm3. As a result of poor experience with these units Mobil and Kellogg initiated a joint development program to determine if the catalyst separation efficiency could be improved. The joint Mobil / Kellogg development program has been successful and extensive. A unique TSS cyclone has been developed which is capable of achieving less than 50 mg/Nm3 particulates in the flue gas. Retrofit designs using the new technology have been developed to improve existing TSS catalyst removal efficiency. The first grassroots Mobil/Kellogg TSS is being constructed and is expected to startup in 1997. It is designed to achieve less than 50 mg/Nm3 particulates in the exiting flue gas resulting in very low stack opacity. This paper discusses the following: J Commercial TSS Particle Collection Efficiency Performance J Mobil / Kellogg TSS Development Program J. Comparison of Mobil / Kellogg TSS Performance to Existing TSS Performance J Commercialization of the Mobil / Kellogg TSS