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Tanya Parise

From: Scott McBryde [smcbryde@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 second 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 impact? 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 guidelines on the fuel. Specifically, what would be the 

impact if using fuels mixed with used lubricating 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 engine 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 would have on the diesel particulate filter and it’s operation: 

 Sulfated Ash Accumulation: Sulfated ash accumulates on diesel particulate 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 present 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 catalytically 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 agents, 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, phosphorous, sulfated ash, engine 

wear metals (copper, iron, etc), arsenic, to be relatively high in the exhaust compared to that of a typical 4-stroke 

diesel engine. These materials will accumulate on the DPF and can cause deactivation of the catalytically active 

sites. In time, this will impair the DPFs ability to regenerate accumulated particulate. The poisoning from these 

compounds will cause irreversible damage to the DPF blocks.

 SOF: Due to the high viscosity and combustion characteristics 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 temperatures to allow for sufficient 

regeneration, as well as increasing the temperature requirements for regeneration overall. 

Best regards,

  

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

MIRATECH Corporation