A CRJ200 EICAS alerted anti-ice duct during climb out so the crew completed the QRH; then because of ice at the destination; the flight diverted to an enroute airport.

Narrative

We received an anti-ice duct warning message while climbing through FL200. We ran the QRH and climbed above icing conditions. We never received the ice caution message after running the QRH. We got above all precipitation at FL290. We contacted Dispatch and Maintenance Control and decided to divert to an enroute airport due to icing conditions enroute and at our destination. We diverted and descended through some icing conditions; but never got the ice caution. We kept the speed as fast as possible to keep the total air temperature above 10 degree C. We declared an emergency and kept our speed above 250 until around 8;000 FT when we were sure we were out of icing conditions. We landed and taxied to the gate. We then moved the passengers to another airplane that was at the divert airport for the night and continued to our destination. The crew worked well together. The Captain did a good job of directing the situation and keeping the passengers and the Flight Attendant in the loop. Maintenance Control and our Dispatcher were very helpful and made our job much easier. The airplanes are getting older.