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Biodiesel Particles Facilitate Diesel Particulate Filter Regeneration

A new study by a team of researchers found that the characteristics of particulate matter resulting from the combustion of 100% biodiesel fuel should facilitate the regeneration of diesel particulate filters (DPF).

In a paper published in Environmental Science and Technology, the team examines the characteristics of diesel particulate emissions and the kinetics of exhaust particle oxidation to estimate the change in regeneration behavior.

The study used a 1996 John Deere off-highway engine fueled with 100% soy biodiesel (B100).

Compared to standard D2 fuel, this B100 reduced particle size, number, and volume in the accumulation mode where most of the particle mass is found. At 75% load, number decreased by 38%, DGN decreased from 80 to 62 nm, and volume decreased by 82%.

Part of this decrease is likely associated with the fact that the particles were more easily oxidized. Arrhenius parameters for the biodiesel fuel showed a 2-3 times greater frequency factor and ~6 times higher oxidation rate compared to regular diesel fuel in the range of 700-825° C.

They conclude that the faster oxidation kinetics should facilitate regeneration when used with a DPF.

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Comments

John McConnell

"....should facilitate the regeneration of diesel particulate filters (DPF)."

Sorry, but, what does that mean?

Patrick

Diesel Particulate Filters eventually "clog" so to speak and need to be regenerated through "burning" the particulate matter in most cases. They are saying the particulate matter from biodiesel lends itself to this "burn-off" process much more easily.

Sid Hoffman

Unfortunately, reduced particle size might be good for vehicles equipped with DPF, but it is bad for vehicles that were made prior to 2008 or whenever DPF becomes standard. Smaller particles become lodged in the lungs more easily and cause far more severe breathing problems than the larger particles.

allen Z

Perhaps combustion/chemistry science could lend itself to make fuels burn with less/smaller particulates. However, smaller particulates may mean the ability to lodge deeper in the lungs, like asbestos, if the exhaust system fails or due to improper designe/manufacturing defect.

Bryan Walton

Don't forget, however, that B100 (the fuel used in this test) not only reduces the size of PM, but it also reduces the amount. B100 has 50% less PM that diesel #2. So, the PM present in the exhaust is smaller, but there is also 50% less of it from the starting point. Another feature that is better than petrodiesel.

John Ard

Does this mean that an older engine (2005 model year) could meet the 2007 emissions regs with B100?

Mike

You still have the NOx emissions to deal with.

Patrick

...and the NOX from most of the biodiesel blends has been shown, quantitatively to be higher than petro-diesel.

Regardless of what you "feel" about smog, the EPA has standards for NOX that cannot be avoided for the implementation of diesel powered vehicles.

Cervus

The EPA and CARB need to get a clue and relax their NOx restrictions so can can more easily get biodiesel and diesel passenger cars on the market.

Scott Vandeweghe

A 10 year old off highway engine is a dinosaur compared to a current build engines. The 1996 John Deere Tier 1 engine emissions levels of 9.2 NOx, 0.4 PM, 11.4 CO using Off Road Diesel (5000 PPM Sulfur) can’t compares to a 2006 Tier 3 off highway engine that emits 4.0 Nox, 0.15 PM, 3.5 CO using the same Off Road Diesel. This research simply makes the B100 improvement appear more dramatic. Consider that a 2007 On Highway EPA Certified diesel on a 5% or 20% Biodiesel blend with ULSF (15 PPM sulfur) emits 0.2 Nox & 0.01 PM!

A B20 Biodiesel blend with ULSF is a viable fuel for on highway, off highway & home heating oil requiring no alterations of the engine or home heating unit that can reduce emissions.

According to the US EPA Clean cities fact sheet DOE/GO-102005-2029 April 2005, B100 produce form soybean oil reduces life cycle CO2 emission by 78% over petroleum diesel…. Oxides of nitrogen (Nox) may increase slightly.

allen Z

How small/light/power-energy demanding/productive are inert gas generators/oxygen generators? I have seen ones for warehouses that are the size of semi-trailers/40' shipping containers for nitrogen/inert gas generation to preserve food. The objective is for a pure oxygen source, not inert gases, to solve NOX problems for ICE's. No N2 means no NOX. If you can generate a pure O2 environment in the cylinder (tempered by cooled recirculated exhaust gas) you can have the same power/torque in a downsized engine. You may install supercharging/turbo to add further power.

d

If you can generate a pure O2 environment in the cylinder (tempered by cooled recirculated exhaust gas) you can have the same power/torque in a downsized engine.

But you have to expend energy to get pure O2, so you might not get much downsizing. Currently pure N2 and O2 are made by differential cooling, which scales quite well upwards which means not downwards. Easier to treat the exhaust. It took several years to get gas cats working well, it will take a couple of years with diesel exhaust treatment, and ULSD rollout isn't even complete yet.

Patrick

allen z- Are you suggesting carrying around cylinders of O2 for engines? A smallish 2.5L V-6 can consume around 200cfm at peak torque rpms.

allen Z

No, not cylinders or differentail cooling. I am talking about molecular separation.

allen Z

differential

allen Z

Usage of molecular sieve or various other technologies is what I am talking about.

Andrey

Allen:

Funny thing: some years ago I was trying to patent same idea, based on pressure swing absorption separation. Aside from terrible bulk, cost, and parasitic energy consumption of the separation system, there is explosion hazard. Pure (even just oxygen-enriched air) on contact with lubrication oil lead to immediate spontaneous explosive ignition. Same with contact with various hot metal surfaces.

Andrey

P.S. ICE using pure oxygen mixed with exhaust was used on experimental German torpedoes during WW2. It was aeroderived Junkers engine with Dr. Wankel rotary valvetrain.

Patrick

The European Respiratory Society (www.ersnet.org) has data indicating strongly negative health impacts of NOX without consideration of smog. With the proliferation of diesel vehicles in Europe this is a great concern to them.

Jonathan Bartlett

No excess O2 is far safer than trying to combust fuel (bio, petrodiesel or gasoline). Compressed O2 AND oil for cylinder wall lubrication is a disaster with or without other fuel.
Reducing the O2 by using more N2 will similarly reduce one of the two components needed for NOx.
Since bio has lower particulates, why not use up to 99% EGR,(with a suitable intercooler), an O2 sensor, and a valve that regulates the 20% O2 content atmosphere added to the ERG to that amount needed to completely combust the fuel.
Zero EGR at full load (lots of fuel, not much excess O2 to combine with N2),
Nearly all EGR at idle and very light loads (not enough fuel to burn all the O2).
Proportional amounts in between?

Paul

Our fleet in Oneonta has been using Biodiesel (B20) for two years with outstanding success. We are on line to burn 100,000 gallons this year. We have had only 1 fuel issue in that time (relating to the expected clean out of an older fuel tank), as opposed to dozens we normally would have experienced in the same time period.
We just received a new 2008 Ford pickup with a particulate filter, and were told explicitly not to use more than B5 or it would clog the particulate filter. All the research I've done shows there should be less particulate matter than the straight D2 Diesel Ford is advocating. I think the local Ford dealer is blowing smoke.
Can anyone offer any help. Thanks.

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