Columbia plant co-owners wrapping up air control installations

Wisconsin Power and Light told the Public Service Commission of Wisconsin on July 31 that after-construction shakedown of new emissions controls for the coal-fired Columbia Energy Center Units 1 and 2 is progressing well.

The utility filed a quarterly progress report with the commission on July 31, covering the April-June 2014 period. The plant is co-owned by Wisconsin Power and Light, Wisconsin Public Service Corp. and Madison Gas and Electric.

The estimated cost of the approved project cost was $627m, excluding allowance for funds used during construction (AFUDC). As of this update the project is forecasted to be completed under the approved cost. The project is currently projected to cost about $599m.

As of June 30, 2014, the overall project is approximately 99.4% complete (Engineering, Procurement, and Construction), which is slightly ahead of schedule.

The tie-in outage for Unit 2 began on Jan. 18 and was completed on Feb. 25. The Unit 1 outage started on April 12 and finished on May 28.

As of the end of June 2014, engineering was about 99.5% complete for the project. Several engineering activities were executed to support the project schedule, most pertaining to commissioning and start-up activities.

All major deliveries have been received. Baghouse bags and cages have been delivered and installed in the Unit 2 Pulse Jet Fabric Filter. Deliveries of bags and cages for Unit 1 are complete and installation was completed in early March. Spare parts continue to be delivered and will continue through the end of 2014.

Babcock and Wilcox (B&W) completed erecting the Spray Dryer Absorbers (SDA), Pulse Jet Fabric Filters (PJFF), and ductwork and support steel from the existing units and the new equipment including the SDA inlet ducts on Unit 1. The erection of the SDAs and PJFFs for Unit 1 and Unit 2 have been completed.

Unit 1 status:

Unit 1 was back on line from the tie-in outage on May 28. After performing flue gas distribution checks, lime and recycle slurry were first injected on May 31. On June 1, the scrubber was already performing at the guaranteed level for SO2 removal of 0.04 lb SO2/MMBTU. Activated carbon injection was started on June 10. Mercury emissions dropped immediately. A calcium bromide solution is also used in conjunction with activated carbon for improved activated carbon collection efficiency and was also started on June 10. Since this time, mercury emissions have been demonstrated to be below the guaranteed emission rate of 0.8 pounds per trillion BTU. Performance and emission guarantee testing was completed on Unit 1 during the week of July 7 through 11.

Unit 2 status:

The scrubber/baghouse systems continue to perform well from an emissions perspective. Contract guarantee and environmental performance testing has been completed and the final report issued. Unit 2 passed all of the tested parameters with good margins. Unit 2 and common equipment was declared substantially complete on May 23. The supplier is obligated to demonstrate system reliability via a 60-day reliability test. This test is scheduled to run through the first full week of August. Although SO2 and mercury removal has been good, the atomizers, used to spray the slurry into the spray dryer vessel, have had vibration issues that have been traced to atomizer motor assembly procedures. The motors were removed and sent back to the manufacturer for repair and testing. Two spare atomizers have been utilized in the meantime. Atomizer lube oil coolers have not performed as expected. Over time, calcium carbonate builds-up in the system and restricts flow resulting in lube oil temperatures higher than expected. B&W has traced the issue to cooling water quality that is out of spec with their design standards. WPL is working with B&W to identify and implement a solution. Improvements should be completed by the third quarter.

On July 2, WPL and the Columbia co-owner partners made a request to the Public Service Commission of Wisconsin to install a selective catalytic reduction (SCR) system on Columbia Unit 2. This additional control would reduce NOx by approximately 50%.

The Columbia Energy Center is located near Portage, Wisc. Unit 1 began operation in 1975 and has a nameplate capacity of 512 MW. Unit 2 began operation in 1978 and has a nameplate capacity of 511 MW.

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.