AEC Lowman Station - coal switching and magnesium-enhanced lime scrubbing to lower operating costs

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:617862

Inkenhaus, W; Babu, M; Smith, K ^[1]; Loper, L ^[2]

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1. Dravo Lime Co., Pittsburgh, PA (United States)
2. Alabama Electric Coopreative, Leroy, AL (United States)

AEC`s Lowman Station is located in Leroy, Alabama. There are three coal-fired boilers at this station. Unit 1 is capable of generating 85 MW without a flue gas desulfurization, FGD, system. Units 2 and 3, with a total of 516 MW output capacity, are equipped with FGD systems. The FGD plant was designed for wet limestone FGD with natural oxidation. Lowman Station burned low sulfur, 1.3 to 1.8% sulfur, coal. In January of 1996 AEC switched Units 2 and 3 from limestone to magnesium-enhanced lime FGD operation. It was determined that the plant could take advantage of the higher SO{sub 2} removal efficiency of the magnesium-enhanced lime system. Major benefits resulting from this conversion were AEC`s ability to switch to a lower cost high sulfur coal while meeting the stringent SO{sub 2} emission requirements. Power cost savings resulted from the lower liquid to gas ratio required by the magnesium-enhanced lime process. Three recirculation pumps per module were reduced to a single operating pump per module, lowering the scrubber pressure drop. Significant cost reduction in the operating costs of the ball mill was realized due to modifications made to slake lime instead of grinding limestone. Prior to switching, personnel from AEC and Dravo Lime Company ran a four week test on magnesium-enhanced lime to obtain scrubber performance data including SO{sub 2} removal efficiencies on the modules while burning a 1.8% sulfur coal. This paper discusses the plant modifications that were needed to make the switch, cost justifications due to coal switching, and AEC`s operating experiences to date. AEC and Dravo Lime Company working together as a team conducted detailed cost studies, followed by extensive field tests and implemented the plant modifications. This plant continues to operate burning higher sulfur coal with the magnesium-enhanced lime FGD system.

• OSTI ID: 617862
• Report Number(s): CONF-970145--
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
ACID RAIN
AIR POLLUTION CONTROL
AIR QUALITY
COAL
COMPLIANCE
DESULFURIZATION
ELECTRIC UTILITIES
FOSSIL-FUEL POWER PLANTS
LIMESTONE
MAGNESIUM
POLLUTION REGULATIONS
PRESSURE DROP
SCRUBBING
SULFUR DIOXIDE