http://www.triplepundit.com/2007/02/blue-and-yellow-make-green-ge-and-union-pacific-team-up-for-a-win-win-win/ Business, Better. Since 2005 Sat, 21 Nov 2009 15:05:57 -0800 http://wordpress.org/?v=2.8.6 hourly 1 http://www.triplepundit.com/2007/02/blue-and-yellow-make-green-ge-and-union-pacific-team-up-for-a-win-win-win/comment-page-1/#comment-14603 Marc Wed, 28 Feb 2007 20:32:32 +0000 http://www.triplepundit.com/wordpress/2007/02/blue-and-yellow-make-green-ge-and-union-pacific-team-up-for-a-win-win-win/#comment-14603 This part of the otherwise excellent post misstates which pollutant is removed by a DPF: "It is a filter, referred to as DPF, which uses high temperature silicon carbide blocks to filter and burn-off exhaust particulates. DPF reduces NOx emissions and the burn-off is converted to carbon dioxide and water." A DPF removes <b>particulate matter</b> (and hydrocarbon gases and carbon monoxide gas if there is a catalytic coating on the filter), not NOx. Different catalytic systems are needed to reduce NOx in diesel exhaust, like hydrocarbon selective catalytic reduction or urea/ammonia selective catalytic reduction. This part of the otherwise excellent post misstates which pollutant is removed by a DPF: “It is a filter, referred to as DPF, which uses high temperature silicon carbide blocks to filter and burn-off exhaust particulates. DPF reduces NOx emissions and the burn-off is converted to carbon dioxide and water.”
A DPF removes particulate matter (and hydrocarbon gases and carbon monoxide gas if there is a catalytic coating on the filter), not NOx. Different catalytic systems are needed to reduce NOx in diesel exhaust, like hydrocarbon selective catalytic reduction or urea/ammonia selective catalytic reduction.

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