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Yes SBG, your 2nd paragraph is exactly the point. As a further consideration, I was sensitized to ammonia way back in HS drafting class when a blueprint machine right behind my back leaked its entire reservoir of high concentration ammonia on the floor and ran under my chair, unbenonsed to me. When I came to in the nurse's office with of course smelling salts under my nose, I was in a new jym t-shirt and had a lump on my head, irritated skin on my back and one arm, and gagging and barely able to catch my breath. To this day I gag on the smell of ammonia, which guess what, is in urine, and many cleaning fluids, and can break through the catalyst system of SCR equipped vehicles.
So on to something else I thought I would put up for everyone's consideration: the chemistry of urea based SCR (assuming I can find all the symbols needed...)
From our HS chemistry: 2NO (Nitrogen Oxide, the brown gas that kills you fast) + CO(NH2)2 (Urea's formula, see the NH2) +1/2 O2 -> 2N2 (Nitrogen in gas form) + 2 H2O +CO2.
This assumes perfect chemistry, and you know what happens when we assume something...
Notice there is water in the after part of the equation. Now with some imagination it is easy to see that if the system is off for whatever reason, that there is the potential for NH2 to get through (breakthrough). Now we have ammonia that has no place to react any more except pass out with the exhaust gases. I don't want to breath that. I can only imagine how people with asthma or COPD or other breathing issues react when getting a whiff of this. Picture standing at a city bus stop, waiting for your bus, and the one that pulls up is not operating correctly (Tell me it isn't so that city buses arn't perfectly maintained...), and you get a lungful of that!
So again going back to the original post, making your own DEF, while doable, is rife with the potential for problems, not the least of which is hugh expenses replacing a damaged cat or 3. My opinion: look for it in BJ's or whatever discount club you shop in, and save the problems. If you are intent on making your own, get the chemistry correct, use the correct ingredients (deionized water, and urea that has no other compounds) and use adequate PPE.
So on to something else I thought I would put up for everyone's consideration: the chemistry of urea based SCR (assuming I can find all the symbols needed...)
From our HS chemistry: 2NO (Nitrogen Oxide, the brown gas that kills you fast) + CO(NH2)2 (Urea's formula, see the NH2) +1/2 O2 -> 2N2 (Nitrogen in gas form) + 2 H2O +CO2.
This assumes perfect chemistry, and you know what happens when we assume something...
Notice there is water in the after part of the equation. Now with some imagination it is easy to see that if the system is off for whatever reason, that there is the potential for NH2 to get through (breakthrough). Now we have ammonia that has no place to react any more except pass out with the exhaust gases. I don't want to breath that. I can only imagine how people with asthma or COPD or other breathing issues react when getting a whiff of this. Picture standing at a city bus stop, waiting for your bus, and the one that pulls up is not operating correctly (Tell me it isn't so that city buses arn't perfectly maintained...), and you get a lungful of that!
So again going back to the original post, making your own DEF, while doable, is rife with the potential for problems, not the least of which is hugh expenses replacing a damaged cat or 3. My opinion: look for it in BJ's or whatever discount club you shop in, and save the problems. If you are intent on making your own, get the chemistry correct, use the correct ingredients (deionized water, and urea that has no other compounds) and use adequate PPE.
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