From:	Dean, Warren SEA <warren.dean@siemens.com>
Sent:	Monday, June 08, 2009 3:30 PM
To:	Schaffner, Karen S.
Subject:	RE: NOx Chapters:  Siemens TDL NH3 slip

OK

-----Original Message-----
From: Schaffner, Karen S. [mailto:ksschaffner@rti.org]
Sent: Monday, June 08, 2009 1:23 PM
To: Dean, Warren SEA
Subject: NOx Chapters: Siemens TDL NH3 slip

Good Afternoon, Mr. Dean:  Thank you very much for the information on Siemens TDL ammonia 
monitoring system you shared today.  I have included a summary of our discussion below and hopefully I 
understood you clearly.  Please feel free to correct me or expand on.  Thank you, Karen Schaffner



The Siemens TDL for ammonia monitoring is in place at approximately 90 to 100 full-scale coal-fired 
units in the U.S.  Facilities measure NH3 slip concentration after the SCR (and SNCR) and before the air 
heater.
Some facilities measure at up to 3 points in the duct between the SCR and AH (for example, at 10 foot 
distances) to account for or eliminate any stratification.  The Siemens TDL unit has a capital cost of 
approximately $40,000 for one point of measurement; measurement at three points could be up to 
$70,000 for capital cost.







Karen Schaffner

Air Quality Engineering Group

RTI International

3040 Cornwallis Rd (800 Park, C311)

Research Triangle Park, NC  27709

phone:  (919) 316 3740

fax:  (919) 541 7155



