Development of a New Diesel Particulate Control System with Wall-Flow Filters and Reverse Cleaning Regeneration

A new particulate control system has been developed and bench tested coupled with the exhaust of a single cylinder diesel engine. This system uses Ceramic monolith Filters for collecting the soot, however, it does not require thermal regeneration for cleaning the filters. Instead, compressed air is employed to remove the soot from the filter in a reverse flow configuration. This type of regeneration was accomplished in two different ways:

• By backpulsing the filter with compressed air.
• By slowly pressurizing the filter casing with air and then suddenly releasing it when the pressure reaches a predetermined value.

During filter regeneration period, the engine exhaust was momentarily released to the atmosphere. To avoid this release, a dual configuration of the system consisting of two ceramic filters operating alternatively has also been designed. Particulates blown-off the filter were recaptured in a baghouse or burned in a specially designed electrical burner. Two special “flip-flap” valves were developed and tested as an alternative to the currently used solenoid valves. These new valves can significantly reduce the complexity and the total cost of the system. Results obtained show that in this system the fitter can be regenerated with very little compressed air without heating the body of the filter; the particulate burner being completely separated from the filter housing. The system was tested with five different types of honeycomb ceramic filters and its performance was very satisfactory.