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Aftertreatment - Precious Metals

Aftertreatment - Precious Metals

Aftertreatment - Precious Metals

(OP)
How many grams of platinum and rhodium are used in a three-way catalyst for a 200hp natural gas (turbocharged, spark ignited) engine?
 

RE: Aftertreatment - Precious Metals

ask the vendors

RE: Aftertreatment - Precious Metals

(OP)
So far they seem reticent to share that info.
 

RE: Aftertreatment - Precious Metals

(OP)
Alternatively, if I knew that the catalyst element was 11.5" diameter and 3.5" thick, and that the precious metal loading was 20g/cuft, and that the platinum and rhodium were used in a 4:1 ratio, then I could calculate that the volume is 0.210ft3, the total mass of precious elements is 4.21g, and that 0.84g of that is rhodium, while 3.37g is platinum.  

What I don't know is whether the final result makes sense - one thing that I worry about is whether the external dimensions of the catalyst element give an appropriate volume for the precious metals loading calculation (20g/cuft based on external dimensions?  based on some sort of pore volume?  based on ?)

 

RE: Aftertreatment - Precious Metals

If you can afford destructive testing, any metallurgical lab should be able to do a quantitative analyse for you. The Elmer Perkins type atomic absorption spectrophotometer is a name that seems to be rising from memories of my study of the subject in 1960 something or other.

Regards

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RE: Aftertreatment - Precious Metals

Someone developing a "business plan"?

RE: Aftertreatment - Precious Metals

"the total mass of precious elements is 4.21g"

That is a good, possibly high, estimate. You are short one element, palladium typically. The precise proportions of which metal are used is very variable.  

Cheers

Greg Locock

SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: Aftertreatment - Precious Metals

Pd is replacing Pt quite a bit in newer catalyst designs.  It is cheaper and generally can withstand higher temperatures.  Manifold-mounted light-off catalysts are generally Pd-only.  Destructive testing is probably the only way to know for sure, but under-floor 3-way catalysts with ~0:16:1 Pt:Pd:Rh and ~30-50 g/ft^3 loading were fairly common for California LEV II and Federal Tier 2 vehicles a few years ago.  Vehicles sold in Europe generally have less PGM loading due to their reduced km-useful-life requirements relative to the U.S. standards

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