Verso to test mercury control additive at coal-fired pulp mill in Wisconsin

The Wisconsin Department of Natural Resources is taking comment until April 17 on a possible approval of a test exemption for Verso Corp.’s Wisconsin Rapids Kraft pulp mill.

The exemption to air permitting rules would temporarily allow the company to apply a calcium bromide solution to the solid fuel used in Power Boilers No. 1 and No. 2 to enhance mercury removal by their individual existing electrostatic precipitator (ESP) control devices used for particulate matter control.

Due to the absence of halogenated compounds in their current solid fuels of low-sulfur coal and wood, mercury vapors released during the combustion of coal are not oxidized. The use of a halogenated additive, such as calcium bromide, is expected to enhance mercury vapor oxidation and the removal of mercury by the ESP. During the proposed research and testing exemption period, the facility is proposing to apply the additive to the solid fuel at a maximum rate of 31.4 pounds of additive per 40,000 pounds of coal.

The covered units, both supplied by Combustion Engineering, are:

  • Power Boiler No. 1 – This spreader stoker boiler was installed in March 1966. It has a heat input rating of 412.3 MMBtu per hour. It combusts coal and wood waste. For particulate matter emissions control, the boiler is equipped with a multiclone and an ESP. This boiler exhausts through a stack that is 213 feet above ground level.
  • Power Boiler No. 2 – This spreader stoker boiler was installed in March 1966. It has a heat input rating of 412.3 MMBtu per hour. It combusts coal and wood waste. For particulate matter emissions control, the boiler is equipped with a multiclone and an ESP. This boiler exhausts through a stack that is 213 feet above ground level.

Verso wants this testing to begin right away, with a test duration of 2-4 months.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.