Boiler Ash

October 16, 1997                                                                                                                                                                                                       ISSUE #68

Recently our sales rep in North Western Ontario, Process Flow Systems, took us to visit the one of the largest paper mills in North America. There are kraft, newsprint, and recycle mills all on the same property.

We were asked to demonstrate our small CP-4 with the sludge that comes from a scrubber on their hog fuel boiler. The water and particulate coming from the spray chamber were a filthy jet of boiler ash.

We did not expect the test to work. As expected, the material just oozed through the press with no dewatering. However it looked like there was potential because some polymer had been added. With the polymer, clear water could be seen forming in the nearby puddles and streams.

By chance nearby there was a pile of paper mill waste fiber. This was added to the ash and water solution, and, bingo! It was like magic. With the fiber as a press aid, the press started producing cake that measured 60% solids.

The application was found to work well with 10% by volume reject fiber. By weight the percentage would have been much lower, as is normal with the use of a press aid.

On-site testing is planned with a larger scale rental press.