Making and Treating NOx formed in NH3 Engines

Patrick Desrochers
Department of Chemistry, University of Central Arkansas
Tenth Annual NH3 Fuel Conference, September 23, 2013


Ammonia has real promise as a green renewable fuel; however its use is not without some of the drawbacks endemic to high temperature combustion processes. Chief among them is the potential for NOx formation in nitrogen-rich oxidizing environments. Nitric and nitrous oxides are prime culprits that plague both entrenched hydrocarbon internal combustion technology but also emerging technologies like ammonia-as-a-fuel. Nitric oxide is implicated in photochemical ground-level ozone production in urban areas. Nitrous oxide is its own double-edged environmental sword, being both a potent tropospheric green-house gas as well as a principle agent in renewed stratospheric ozone-depletion (Science 2009, v326, p. 123). Successful ammonia-as-a-fuel initiatives must deal with these realities or risk marginalization before reaching maturity.

Fortunately considerable research exists on the interrelationship of NOx and ammonia. These lessons come from current exhaust treatments for lean-burn gasoline and diesel engines and model studies of the pure gases in both catalyzed and uncatalyzed environments. This presentation will survey some of these lessons with the goal of informing the ammonia-as-a-fuel community of possible solutions to the NOx / ammonia problem.


Download this presentation [PDF, 1.0MB].


Patrick Desrochers, Department of Chemistry, University of Central Arkansas
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2 responses to “Making and Treating NOx formed in NH3 Engines

  1. so, it seems that NH3 becomes a storage medium for electricity and later as a method to combust hydrogen. or strip hydrogen off in terms of it being used as a fuel cell.

    NOx is an issue with combustion, is it also an issue when used to regenerate electricity in a fuel cell. It appears that NOx is a more damaging greenhouse gas than CO2 but I’m not clear on how it differs proportionately or how it compares to methane and other gases.

    It would seem to be most desireable to not create NH3 from natural gas due to the methane venting and water used in fracking natural gas.

    That puts us back to electricity generation. Which seems to take us to nuclear. There is not much discussion in ecoenergy forms about integrating these two. Using nuclear generated electricity from “spent” nuclear waste from breeder reactors. We know where the fuel is located, allegedly there is 200 years of “electrical power” stored in it by using an alternative type of reactor (fluoride based) that is not expensive to build ($100million) not water intensive, and safer than the breeder reactor, and no plutonium generation.

    So, for those more expert than me, how much of this is true, real, possible, or potentially implementable?


  2. Left out a bit,what I’m getting at is creating NH3 from electricity, that is in turn generated from nuclear waste that is in “safe” storage in various places around the country.
    We thus avoid more energy intensive and subsidized uranium mining and refining that way, we avoid more hydraulic fracturing that way (water intensive/methane releasing), and it appears that nuclear waste is a viable source of clean electricty (but I’m no physicist). As I understand it, after one uses the spent nuclear waste to generate more electricity, the half-life of the remaining waste is dramatically shortened from what it was prior to reuse. (1000s of years to hundreds of years).

    Seems something good should come from the trillions of dollars spent creating 33,000 nuclear weapons since 1955 and we could reduce environmental risk from greenhouse gases and nuclear waste simultaneously.

    For those more educated and involved in these areas than I, please comment.

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