Featured Ammonia for NOx reduction

yes aviation is completely different. 10,000 psi hydrogen is a non starter because it much more heavy than methanol per unit energy when tanks are included, and methanol is around twice as heavy as 100 octane gasoline used in general aviation or jet fuel in most commercial aviation, and requires tank sizes more than twice as large. Ammonia or a similar nitrogen/Hydrogen compound could be used in aviation in the future.

 

It is still used in commercial refrigeration.

 

Water washing exhaust is as old a technique as the Diesel engine.

This technique (below) is newer, more intensive and less effective than the "old" bath method.

Ship exhaust washed to protect the environment - Hoyer Motors

My father road hundred ton ore cars underground during the 60's and 70's

All mining equipment was diesel over gasoline because monoxide, soot and NOx could be cleaned with a 55 gallon drum of water (gasoline exhaust isn't as cleanable this way)
He had to change the water 1-3 times a shift depending on how hard he was running.

He said it was usually 1 gallon of water for every 5 gallons of fuel burnt to keep his air breathable during operation.

Understand that "other" methods combined with low sulphur fuel could reduce the water required to clean massively, for example a 2 way cat + low sulphur might meet emissions with minimal water injection needed.

Cheap additives to the water also increase its potency. ( like a little driveway salt)

 

Thanks. I had no idea you were talking about scrubbers on ships. Traditionally they just took the pollutants out of the air and dumped it in the water, which was put into whatever body of water the ship was on. I call that switching from air to water pollution. Your link talks about new closed systems that keeps the waste on the ship then processes it on shore, definite an improvement. The boat method would not work on cars, because who wants to carry arround a tank of sludge with you.

Scrubbing NOx is not all that effective on a ship compared to SCR. The high sulfur fuels on ships has makes SCR impossible as sulfur fuel poisons the catalyst, but Some ships scrub the exhaust and then can use SCR to greatly reduce exhaust.

Definitely lower sulfur fuel reduces the problem, and in many environmental areas it is now required for ships. NOx is much less of a problem on the seas than it is on land, so most don't require reducing it as much. All of the North America and Europe now use ultra low sulfur diesel for cars, trucks, and busses, which pollutes less on older vehicles, and allows SCR and particulate filters to work.

 

In a car application you wouldn't collect the sludge

#2 makes so little that the drip from your pipe would be the ppm of sludge, SCR would be unnecessary only necessary components would be a 2 way cat and EGR.

NOx is virtually eliminated by water wash and by volume the occasional drop out of your pipe would eliminate it (that and less would be formed in the first place)

So although the technique is used on ships the results on a car are apples and oranges different.

Just as it was very different on ore cars compared to ships.

 

If you just let it drip out the tail pipe, it is just moving the pollution from the air to the ground and water. Then when it dries on the pavement, passing traffic will just resuspend it into the air.

The link you provided makes no mention of NOx reduction. It has a low solubility in water, and when it does dissolve into it, it forms nitric acid. The exhaust system will have to with stand that.
http://pubs.acs.org/doi/abs/10.1021/es102214b

 

You over estimate the amount of soot made by a modern auto diesel, quantities would likely be dwarfed by an order of magnitude by rubber and asphalt dust made by tire wear on pavement. (When talking grams per mile)

The soot also tends glob and bind to asphalt , it's not similar to actual dust, it will cake and coat.

Post injection Water prevents NOx formation in the first place (lower post combustion temps) and the remainder degrades rapidly in the presence of water, soot and VOC.

As you mentioned
NOx is highly reactive and water is a catalyst a stainless exhaust is a must if the 5 minute NOx environmental half life was deemed to long, a very small percentage of cheap calcium compounds in the water mist would neutralize it.
Nitric acid degrades rapidly when mixed with soot and dirt anyway.
(And again talking on the grams per mile order)

When we have refineries making on the order of 80-300 grams of NOx per gallon of gasoline shouldn't we perhaps worry more about reducing consumption of fuel at any cost?

How the refineries came to own our air pollution regulators - LA Times

 

The amount of soot on modern diesel cars is low because of the DPF. A water scrubber isn't needed if one is in place.

Anything dumped on the road will eventually get resuspended in the air or end up in water ways.

Water injection and water scrubbers are two different things.
Injection can reduce NOx by lowering cylinder temperatures. It also has potential to improve efficiency, and has been a performance booster for decades. The six-cycle engine also has promise. The water used is converted to steam though. As steam, won't be effective at cleaning the exhaust of soot and SOx since they are all essentially in a gas phase. A water scrubber, that is using liquid water, is used for that on ships. Scrubbers are likely also in use on some power plants.

Calcium compounds mixed into water that are misted into the exhaust will become deposits in the exhaust system.

 

Oh the irony .... on 1 thread, we throw up the evils of EV's because they 'might' re-suspend road soot because they 'might' be heavier than a similarly sized ICE transportation. Yet here ... it appears some would whant to give a complete class of particulate/soot generating cars a free pass.

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