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Featured Ammonia for NOx reduction

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by bwilson4web, Jun 28, 2017.

  1. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Source: Real World NOx reduction by City-SCR

    [​IMG]

    Diesel vehicles need SCR catalysts to reduce NOx and SCR catalysts need ammonia to work. ASDS™ unlocks the full potential of the SCR by dosing gaseous as opposed to liquid containing ammonia into the exhaust stream. This allows for a NOx reduction of up to 99% in all climates and real driving conditions including slow city traffic.

    ASDS™ achieves 3-5 times better NOx reduction in city driving with no CO2 increase (cold engines) and 20% better NOx reduction on motorways (hot engines)

    [​IMG]

    That is an anhydrous ammonia tank being exchanged. Compare that to the 5-10,000 psi hydrogen fool-cell tanks, this is the way to go. Feed the ammonia to a catalyst to break it down into nitrogen and hydrogen and feed the fuel cell.

    Bob Wilson
     
  2. austingreen

    austingreen Senior Member

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    This is probably mainly for truck/bus market where there is cost advantages and efficiency gains for using diesel over cng or lng at current oil prices. Hydrogen is really a non-starter here as is ammonia.

    I believe they are using the ASDS with SCR to try to get to levels similar to cng or lng (compressed for short range, liquid for long range as its 1/2 size tank but is more costly in terms of dollar and energy). A lng tank is about twice the size of a diesel tank for similar range, a 10,000 psi hydrogen tank is huge in comparison. CNG is cheaper than hydrogen and in a hybrid bus or truck, more efficient than a fuel cell bus in current fuel mix for hydrogen stations.

    IMHO picken's original plan is right for america, but it takes government dollars for infrastructure. Reduce the price of natural gas burning engines, and use cng or lng for these vehicles, then reduce natural gas on the grid by slowly building more renewables. Germany has shown that excess renewable generation can safely be used to generate hydrogen that can be used in natural gas infrastructure. In the US this doesn't work because natural gas is so low cost. Alternative is to keep using diesel and spending more to clean up emissions. SCR isn't the main cost driver it is particulate filters. This may get solved by evolved engines that work in the lab and burn both diesel and gasoline.
     
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  3. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Just curious, is there any reason for diesels, fully warmed, to be left idling? Or is it just mindset at play?

    Sorry, I am off-topic, just realizing.
     
  4. Rmay635703

    Rmay635703 Senior Member

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    To run "cabin" loads

    The answer is to put plugs on trucks or have a reliable onboard electric storage system to cover.

    Some semis have a small diesel gen set but that doesn't really solve the issue
     
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  5. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Turns out some truck stops are setting up plugs for the truckers.

    In this case, the ammonia is used to neutralize/regenerate the NOx SCR, not as a primary fuel. But I was trying to point out how practical anhydrous ammonia is due to the lower pressures and easily handled infrastructure. If I were challenged to do a cross-country, fuel cell trip, it would be using anhydrous ammonia with a converter because it is so common in farming.

    Now if I wanted to do part of it at 4,000 mph:
    [​IMG]

    Bob Wilson
     
  6. Sam Spade

    Sam Spade Senior Member

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    WOW. Another brilliant discovery, Bob.
    And another invalid conclusion too.
    Obviously you have never dealt directly with anhydrous ammonia.
    The vapors will disable, disfigure and KILL you rather quickly.......unlike hydrogen vapors.

    Oh, and it has other valuable uses too.......like cooking Meth.
     
  7. Trollbait

    Trollbait It's a D&D thing

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    This isn't anhydrous ammonia, but cartridges with the ammonia locked up in a solid.
    Innovation driving wel-being - Ammonia Storage and Delivery System (ASDS)

    "Abstract: SCR systems that store a solid ammonia precursor and deliver gaseous ammonia reductant to the SCR catalyst allow for improved low temperature performance compared with urea-SCR systems. Two main groups of materials that can store ammonia and release it on heating include metal chloride ammines and ammonium salts. Solid SCR systems under development utilize strontium ammine chloride or ammonium carbamate for ammonia storage." - Solid Reductant Storage for SCR Systems

    There is also this bit, "However, it should be noted that solid SCR technologies cannot address low temperature SCR issues that are rooted in the chemistry of ammonia, rather than urea. Such an issue is the formation of ammonium nitrate (NH4NO3) via reactions between NO2 and NH3 at temperatures below 200°C. .... Hence, while solid SCR systems can help meet NOx emission limits in testing over regulatory test cycles with low temperatures—such as the chassis FTP schedule—they still may face limits in reducing NOx in applications characterized by prolonged low exhaust temperature operation."
    I seem to recall something about diesel and ammonium nitrate.:eek:

    This could be better for SCR in trucks than DEF, but will likely be a non starter in cars. The public didn't like the idea of adding another fluid to their cars at first. I think having to swap out cartridges will have more push back.

    I don't see anhydrous ammonia becoming a thing for fueling cars, because of the safety issues. While to a much lesser extent than hydrogen and even CNG, it also needs a pressure vessel to contain. That puts packaging limits on vehicle design.
    A Volvo partnership developed a diesel powered fuel cell, that they might offer as an onboard generator for trucks.
     
  8. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I worked one summer at an ammonia refrigerant, ice plant so I don't share the concern. Farming seems to work just fine with anhydrous ammonia.

    Bob Wilson
     
  9. austingreen

    austingreen Senior Member

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    Oregon Business - Oregon startup bets on ammonia to deliver clean energy

    These guys liked your idea back a decade ago. All the problems are still there. Gasoline is less expensive, methanol is less expensive, ammonia is more expensive, and fcv seem less likely to be viable in a decade.

    I do not see any advantage to heavy vehicles versus diesel phev, lng, bev, or cng. Depending on the vehicle each of these technologies will be less expensive as well as often lower polluting.

    Light vehicles, can't see anyone going through the trouble of anhydrous ammonia when you can get a prime or camry hybrid, or tesla. That's the kind of thinking that had people saying the mirai would out sell the telsa model S.
     
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  10. hill

    hill High Fiber Member

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    let me know when you get certified to fly the x15's launch platform . . .

    [​IMG]

    and then there's the maintenance costs .... probably cuts into efficiency
    ;)
    .
     
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  11. wjtracy

    wjtracy Senior Member

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    Is it correct to say SCR is what (VW) diesel autos would have needed all along to meet emissions specs?
    I was expecting this SCR for years, but then VW/others said they could accomplish low emissions without it (as we now know it was not true).
     
  12. Trollbait

    Trollbait It's a D&D thing

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    We use it to pretreat cellulistic biomass before enzymatic hydrolysis. It opens up the cellulose structure, making it easier for the enzymes to work.Most of the work is done in the lab's fume hood, but we've done some larger scale experiments outside. A whiff of ammonia can be very unpleasant.

    Farming is a more dangerous profession than what most Americans are exposed too.

    Compared to hydrogen, anhydrous ammonia(AA) doesn't need to be stored at such high pressures, and it might be possible to skip the requirement of detection sensors with it. While we are talking of just hundreds of pounds of pressure to thousands, that is still enough impact the design of the fuel tanks to increase their weight and bulk, and attending packaging issues, over that of liquid tanks.

    Unlike hydrogen, AA is not benign to the human organism and environment. It converts to a strong base when it readily mixes with water. So getting caught in a leak can lead to caustic burns of the eyes and mucus membranes. Long term exposure to lower levels will lead to pneumonia and other respiratory issues. It kills aquatic life when it gets into water ways. This means any dispensers for personal vehicles will be about as over engineered as the ones for hydrogen.
    Yes. The systems using DEF/AdBlue have a catalyst upstream of the SCR system catalyst that converts the urea in the fluid into ammonia for the system to reduce NOx with; it needs the exhaust system to be hot for that urea to ammonia conversion to work. In low load situations, like city driving, the exhaust might not get hot enough. Directly injecting ammonia will reduce more NOx under those conditions.

    In the early days of SCR, the public was hesitant about adopting it. The idea of another maintenance idea in the form of adding DEF was seen as a disadvantage. Not having SCR w/ DEF was seen as a plus on the Jetta. In addition to the other harms of VW's cheating, the US was cheated out some good diesels from Honda and Mazda. Seeing the Jetta, they tried to go the non-SCR route, but failed. Just something else to point out to any VW cheating apologists you come across.
     
  13. austingreen

    austingreen Senior Member

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    SCR works. The VW system works. The problem with the VW system is to get it to work properly you need to burn a lot of extra diesel, and need to drive long enough to get things hot. They manipulated the system where it would cut pollution when driven like the epa test, then increase efficiency in users hands while pumping out pollution. If the EPA test actually looked like how people drove today instead of pre wwII LA, then the cheat wouldn't have worked, and there are many other cheats, but this one put out the most pollution. Neither the SCR or particulate filter work as well as advertised in short city drives on any of these diesels. In Europe it is more of a problem with more diesel cars. I do not think that costs are worthwhile for diesel today for cars, though there are advantages to trucks and SUVs in the light vehicle market. ANhydrous ammonia wouldn't work for the consumer market though. The idea of anhydrous ammonia can definitely make NOx lower in medium and heavy trucks and buses that do city driving, and is probably a decent idea in polluted cities like LA, Houston, Pittsburgh - and many foreign capitals like London, Paris, Beiging, etc. CNG is an alternative for short distance vehicles like this, that produce less unhealthy pollution but often produce the same or more ghg. LNG is a sollution for these that do a lot of long haul plus city driving if there is a lot of infrastructure. CNG and LNG currently cost more for the vehicle and maintenance than diesel. In the US the fuel is much less expensive, but it can cost more in Europe.
     
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  14. Rmay635703

    Rmay635703 Senior Member

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    Water injection before during or after fuel injection removes NOx and particulate and CO .
    Post water wash removes 100% of NOx (like diesel ships do)

    Too bad our government feels nobody would fill the water tank if that was the treatment method
     
  15. austingreen

    austingreen Senior Member

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    Diesel Ships don't remove 100% of NOx, they are more polluting than most land vehicles. and are very different engines than those in cars, trucks, and busses. I am unfamilar with the post water wash though, can you point me to a link on the text. I am curious to how this works.

    I don't think the government is in any way against water injection. They probably would require the vehicle would be disabled like it is for empty urea on a SCR vehicle if that is what is being used for pollution control. SCR has a greater reduction in NOx than water injection, but water injection especially with a methanol/water mix can cool the charge, increasing hp and efficiency in many situations, while decreasing formation of NOx. Neither water injection nor urea based SCR work great on a cold engine.
     
  16. bwilson4web

    bwilson4web BMW i3 and Model 3

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    We're talking more along the pressures of a CO{2} cartridge or fire extinguisher. It is being dealt with today:
    Handling Anhydrous Ammonia Emergencies | Firehouse

    [​IMG]

    [​IMG]
    If we're comparing relative hazards, I prefer lower pressure tanks than higher. Pressures low enough that a 'bladder' type liner becomes a practical, mitigation (i.e., self sealing.)

    Bob Wilson
     
  17. Trollbait

    Trollbait It's a D&D thing

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    Yes, but a pressure vessel means you are limited to cylinders and related shapes for the car's fuel tanks. These are space inefficient, and put constraints on vehicle design. If that is acceptable, then why not just go with CNG for less cost.

    How greatly do personal cars outnumber farm trailers for AA?
     
    #17 Trollbait, Jun 29, 2017
    Last edited: Jun 29, 2017
  18. austingreen

    austingreen Senior Member

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    I definitely agree bob, but the likely target of this type of tech - a fuel cell amonia vehicle has to be where the tax incentives are highest. That is probably LA metro and the bay area in California. These are also the place the prius and tesla do best. Unfortunately in traffic jams in these places its very hard to get emergency crews, and the agency pushing fuel cells, is part of a lobby with hydrogen.
    or really methanol. Yeah I forgot politics ;-)

    Methanol is the least expensive hydrogen carrier. Methanol can be inexpensively made from hydrogen provided by electrolysis, and costs much less per gge, than 10,000 psi hydrogen when actual costs of a station and electricity are taken into account. Methanol can also be made from natural gas, just like ammonia and hydrogen, but can be transported and delivered much less expensively. There have been sucessful trials of methanol for cars, but these were dropped because of pressure from the fuel cell and ethanol lobbies.

    Why is the hydrogen lobby against methanol? It is fairly simple. Although it would cost less to put a methanol reformer in a car like the mirai and clarity, than the high pressure hydrogen tanks, there is a small efficiency hit to reform the methanol. This can be hidden on 10,000 psi hydrogen by not accounting for the energy it takes to produce, distribute, store, and dispense.

    Say the reformer is 95% efficient, the 67 mpkg clarity (most efficient fuel cell) now becomes 64 mpge methanol. For about $200 more toyota could make the camry hybrid flex fuel and run on gasoline to 100% methanol (the easiest to transition type vehicle) a 52 mpge methanol vehicle. Yep people may say that will use 23% more fuel, and isn't as quiet, etc, but for most it is good enough. There is no range anxiety or waiting for stations to be built because you can use gasoline, and stations are very cheap compared to hydrogen, and fuel is much less expensive when dispensed properly than 10,000 psi hydrogen. No one is going to say that methanol fuel cell car gets car pool stickers and $13K from the government because it is 23% more efficient. The new camry hybrid is a much better car, as cars go than the mirai and clarity, unless you want to stand out. If that is not good enough the prime stands out more, and a flex fuel version will have a higher mpge using methanol and electricity than the clarity and mirai. A nail in the coffin will be the clarity phev when it comes out. I expect the fuel cell lobby to continue to be against methanol. Amonia may be as inexpensive as methanol, but you can't also burn it in a little modified flex fuel car, making building stations a much worse investment/government policy. Without strong support from the fuel cell lobby, I don't think Ammonia fueling would take off, and with support, they have the problem of reduced efficiency on the sticker.
     
  19. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I'm OK with methanol:
    • CH{3}OH - 32 g/mol -> n% H{2} recovery requires 1 mol CO to give 2 mol H{2}
    • NH{3} - 15 g/mol -> 100% H{2} recovery, 0.5 mol N{2}, 1.5 mol H{2}
    My interest is in aviation and NH{3} is a high density, hydrogen carrier compared to the alternatives. For an aviation fuel cell, ammonia is the second best. The first, liquid hydrogen but it is low density.

    Bob Wilson
     
  20. Sam Spade

    Sam Spade Senior Member

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    Just because I have never seen it, therefore it does not exist. Brilliant. :rolleyes:

    I have SEEN ammonia injuries, both in refrigeration uses and in farming.
    They are NOT pretty.

    And your experience must have been a LONG time ago......because I think that ammonia is NOT commonly used in refrigeration anymore.......at least not commonly.