E [C]/R Incorporated
                  Providing Environmental Technical Support Since 1989




MEMORANDUM   

DATE:		May 11, 2011

TO:		Melanie King, EPA OAQPS/SPPD/ESG

FROM:	Tanya Parise, EC/R, Inc.

SUBJECT:	Summary of Calls with Vendors of Diesel Particulate Filters (DPF) 

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      The purpose of this memorandum is to present a summary of information obtained during calls with vendors of diesel particulate filters (DPF) for stationary diesel engines.  Below is a summary of the April 4, 2011 discussion with Scott McBryde of Miratech and April 5, 2011 discussion with Jim McDonald of Rypos.
      
Miratech

	Scott McBryde of Miratech conservatively estimated that DPF cleaning for ash accumulation would occur every 2,000 to 2,500 hours of operation, or roughly three times per year.  The estimated frequency of cleanings was based on assuming that a low ash lube oil is being used.  The Miratech DPF system consists of 9 blocks, in a 3" x 3" array for a 200 kilowatt (KW) (268 horsepower (HP)).  The DPF could be cleaned on-site by vacuuming or blowing out the ash, Scott explained.  It would take 1 day or less to do the cleaning and the cleaning would not require a skilled technician, according to Scott.

Rypos

	Jim McDonald of Rypos indicated that for engines in the 117 KW to 372 KW (157 HP to 499 HP) size range, the capital cost of the Rypos DPF system is approximately $12,000 to $18,000) and the system is an active DPF system.  It has a wire mesh filter, and it is continuously regenerated with a current that is run from the engine.  According to Jim, the DPF should still achieve the desired reductions even at lower exhaust temperatures.  The DPF can tolerate up to 500 parts per million sulfur fuel, but there could be issues if the fuel has used oil blended into it, Jim said.  In terms of the maintenance, the ash that drops to the bottom would have to be vacuumed out approximately once a year.  This can be done by the engine operator with a shop vac.  In response to the Alaska concerns about the engine shutting down if there is a problem with the DPF, there is a system available that is used for fire pump engines that could be used, where the engine would continue to operate even if there was a problem with the DPF.  Jim noted that the operator could install a timer that would lead to engine shutdown if the problem is not fixed in a certain period of time.

