Multiple Industrial Coal-Fired Boilers

Application

Seven industrial coal-fired boilers (pulverized cyclone, spreader stokers, rotary underfeeds) all exhaust into one Standard Havens off-line pulse jet baghouse. Bags are 19' and 22' long; A/C = 5.00 cfm/ft2 (gross) and 5.35 cfm/ft2 (net); temperature = 350-375ºF; grain loading = 1-2 gr/acf; pulse pressure = 125 psig.

Optimization Potential

Severe maintenance problems due to short bag life and high DP caused loss of full steam load and unacceptable stack emissions. Customer tried several different filter media, including 16.8 oz and 22 oz Teflon® B fiberglass, felted fiberglass, and Nomex® felt. Sonic horns, diffusers, and increased pulse air capacity were tried with no success. The avg. DP was >15" w.g. across tubesheet at 900m - 1mm lb/steam; bag life = 6 mos.; stack opacity = 5-10%.

Solution

Installed 5,880 GORE® membrane/Teflon® B fiberglass fabric filter bags.

Results

Customer achieved full load airflow with a 6" DP across tubesheet which allows systems to run at a full steam load (1.3 MM lb steam). Tests of filters at 6-mo. intervals reveal good retained strength and flexibility, good permeabilities, and no dust penetration or bleed-through. Average bag life has been 96 months with one trial compartment at 123 months. Pulse pressure has been reduced to 60 psig. Maintenance on the filters has been reduced to an occasional monthly check of their condition. The stack emissions are < 3% opacity.