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### Tanya Parise

From: Scott McBryde [smcbry de@miratechcorp.com]
Sent: Monday, May 23, 2011 7:35 PM
To: Tanya Parise Subject: RE: RE: DPF info for engines in rural Alaska

HI Tanya,

Please see attached feedback from engineering on your seco nd question. If you have any questions please do get in

touch.



### If used oil is blended into the fuel that is burned, what is the impac t? I saw the pollutants to avoid in the Installation Guide you sent (and that they should be below 5 ppm) and also noted the reference to the projectspecific documents provided by Miratech for other gui delines on the fuel. Specifically, what would be the impact if using fuels mixed with used l ubricating oil (up to 1.75% of the total fuel, with the sulfur content of the used lubricating oil being <200 ppm and meeting the on-specification levels and properties for used oil in 40 CFR 279.11)? It looks like some of the on-specification levels would be higher than what is recommended by

Miratech. What are the implications of that?

Disclaimer: note that 1.75% of the total fuel (assuming by volume) is a large amount of lubrication oil to be burning. For reference, a typical 4-stroke diesel engi ne consumes about 0.07% lube oil of the total fuel consumption by volume. This is roughly 25 times more oil being consumed.

Below are thoughts as to the most notable impacts that this w ould have on the diesel particulate filter and it’s operation:

 Sulfated Ash Accumulation: Sulfated ash accumulates on diesel particu late filters under normal operation. Since this is not regenerated, it will accumulate over the life of the DPF but a majority of this ash can be removed by vacuuming/blowing the deposits out of the DPF blocks. With such a high oil consumption rate, we expect the ash deposition rate to be much higher than usual. At pr esent no “real world” data would exist for such high oil consumption rates. The customer should monitor differential pressure across the DPF closely to observe the rise in pressure drop and use that information to schedule DPF cleaning accordingly.

 DPF Poisoning: As was mentioned, our DPF blocks are catalyti cally active and are susceptible to poisoning by various compounds outlined in the documents referenced. Used lube oil can contain many harmful compounds. Some of these are put in the lube oil as anti-wear agent s, detergents, etc and some of these poisons are a result of the oil being used in an engine crankcase. We would expect levels of zinc, phos phorous, sulfated ash, engine wear metals (copper, iron, etc), arsenic, to be relatively hi gh in the exhaust compared to that of a typical 4-stroke diesel engine. These materials will accumulate on the DP F and can cause deactivation of the catalytically active sites. In time, this will impair the DPFs ability to rege nerate accumulated particulate. The poisoning from these compounds will cause irreversible damage to the DPF blocks.

 SOF: Due to the high viscosity and combustion characterist ics of lube oil, the soluble organic fraction (SOF) of the diesel particulate coming out of the engine will likely go up. This means that the particulate matter will have a higher level of unburned hydrocarbons attached to it. Essentially, this means that the particulate accumulating on the DPF will likely be a wetter, stickier particulate that is more difficult to regenerate. This will increase the duty cycle requirements for engine operation a higher loads that produce exhaust te mperatures to allow for sufficient regeneration, as well as increasing the temper ature requirements for regeneration overall.

Best regards,

Scott McBryde, Western US & International Sales Manager - Power Generation MIRATECH Corporation