Stack emission reduction of FCC catalyst fines has always been an important issue in refineries, not only to protect downstream equipment, but in particular to meet local environmental and governmental legislation.
Refiners worldwide need to revamp their FCCU regenerator off-gas systems, while new grassroots refineries need to implement the latest filtration technology to reduce stack emissions. In many cases, conventional separation technology is no longer sufficient to meet these stricter emission guidelines.
Most in the industry are now aware that many countries require stack emissions to be lower than 50 mg/Nm³. In response to increasingly tighter emissions standards, Royal Dahlman has developed a filter system designed to further decrease particulate matter emissions, which can replace an ESP, or in some occasions, the TSS.
The recently installed Dahlman filter system was built on the pad foundation of the refinery client’s existing ESP, and has been successfully in operation for more than two years. The system reduces air pollutant emissions in line with EU requirements for Best Available Techniques for oil refineries (BREF on mineral oil refineries) and the EU Directive 2010/75/EC (Industrial Emissions Directive). Since then, it has become the best available technology for emissions reduction downstream from the waste heat boiler. It should be noted that:
- The new filter system outperformed the ESP that it replaced.
- The costs for this system were significantly lower than any other flue gas cleaning technology.
A full flow flue gas filter is especially designed to remove catalyst fines from FCC flue gas after the waste heat boiler and reduce stack emissions to the lowest possible level. The main benefits of a full flow filter package are impressive:
- Significantly lower OPEX
- Emissions << 10 mg/Nm3 (guaranteed)
- No sensitivity to (sudden) solids load changes
- Small plot space
- No risk on explosions (ESP)
- Dry solids disposal, no need for further processing (wet scrubber)
- No visible plume (wet scrubber).
Where conventional systems (wet scrubbers or ESP’s) reduce catalyst fines emissions to an average level of 20 – 40 mg/Nm3, Royal Dahlman’s advanced FCC Full Flow Flue Gas Filter technology guarantees a PM stack emission << 10 mg/Nm3.