In Fluid Catalytic Cracking (FCC) processes, widely used in oil refineries, the separation and recovery of powder catalysts is a major concern.
Particularly, the concentration of catalyst after the FCC regenerator is usually over 150 mg/Nm3. Since these levels of emissions didn't represent any environmental harm in the past, they were not controlled by any separator or filter. Plant managers main concern was to clean a fraction of the gas to produce energy in a Turbo Expander, or similar, while concentrating the rest of the pollutant in a dirty gas fraction and releasing it to the atmosphere.
With stricter emission limits, plant managers have to control catalysts emissions and therefore need a very robust particle collection system, capable of withstanding temperatures of many hundreds of degrees, while being more cost effective than expensive sinterized filters. The system shall be placed immediately after the regenerator and replace the separator (option A), or after the particle separator in the dirty fraction gas stream for emission control before the flow is combined to go the WHB (Waste Heat Boiler) and then through the stack (option B).
Client's needs include a low maintenance cyclone system efficient enough to comply with regulatory PM limits, thus avoiding the use of a filter.
Black Powder is a solid contaminant found in natural gas transmission and distribution systems throughout the world. It consists primarily of iron oxides, iron sulfides and some silica which results from internal erosion and corrosion of carbon steel pipelines.
Either when it is attached to the pipe wall or collected in the pipe bottom, black powder increases roughness, decreases flow area and increases pressure drop. It can cause a wide array of problems, including product contamination, erosion wear in compressors, instrument clogging, erosion and sealing problems for valves as well. Damages in equipment range from large plant burners to residential home appliances.
An adequate solution has eluded suppliers this far. Available commercial cyclones are only efficient for larger sized particles and cartridge filters clog continuously, sometimes multiple times each day. Magnetic separation technology results in very high investments. Maintenance operations require inordinate amounts of manpower and pigging and other maintenance operations entail a lot of downtime.
Clients' needs include a very high efficient final dedusting system, to apply upstream or instead of cartridge filters, which can ensure particle collection for the whole spectrum of particle sizes, and simultaneously reduce maintenance and operation costs.