McIntosh Unit 4A PCFB Demonstration Project Advanced Electric Power Generation Fluidized-Bed Combustion Timeline | References | Contacts | Map | PDF Version

Project Objective

To demonstrate Foster Wheeler's coal-fired Pressurized Circulating Fluidized Bed (PCFB)  technology coupled with Siemens Westinghouse's ceramic candle type hot gas filter and power generation technologies, which represent a cost-effective, high-efficiency, low-emissions means of adding generating capacity at greenfield sites or in repowering applications.

Technology/Project Description

The project resulted from a restructuring of the DMEC-1 PCFB Demonstration Project awarded under the third Clean Coal Technology solicitation. In the McIntosh Unit 4A project, first of the two Lakeland projects, the flue gas from a PCFB combustor/boiler will drive a gas turbine. In the the McIntosh Unit 4B project, the second of the two Lakeland projects, the integration of a gasifier and topping combustor (topping cycle) with the PCFB boiler will be demonstrated, forming an Advanced Circulating Fluidized Bed Combined Cycle Power Plant. (see McIntosh Unit 4B Topped PCFB Demonstration Project).

In the first demonstration, dried coal and limestone are mixed and blown into the PCFB boiler with air by way of a lock hopper feed system. Combustion takes place at approximately 1,560-1,600 °F at a pressure of about 200 psig. The resulting flue gas and fly ash leaving the PCFB boiler pass through a cyclone and ceramic candle type HGPFS to remove the ash. The hot gas leaving the HGPFS is expanded through a gas turbine, which is a modified Siemens Westinghouse V64.3 gas turbine. The gas inlet temperature of less than 1,650 °F allows for a simplified turbine cooling system. The hot gas leaving the gas turbine passes through a heat recovery unit used to generate steam. Heat recovered from both the PCFB boiler and heat recovery unit is used to generate steam to power a reheat steam turbine.

The unit is being designed to burn a range of coals, including the Eastern Kentucky coal burned in McIntosh Unit No. 3 and high-ash, high-sulfur coals that are expected to be available at a lower cost. Limestone will be purchased from nearby Florida quarries. Ash will be disposed of in landfills or sold. The project also includes an  atmospheric fluidized-bed unit that can be fired on coal or char from the carbonizer and will replace the PCFB unit during times of PCFB unavailability, allowing various modes of operation.

McIntosh Unit 4A PCFB Demonstration Project Process Flow Diagram Larger jpeg or wmf version

 

Status/Project Accomplishments

On December 19, 1997,  the City of Lakeland and the Department of Energy executed a cooperative agreement which formally restructured the DMEC-1 PCFB Demonstration Project and relocated it at Lakeland, Florida. The McIntosh Unit 4A and the follow on Unit 4B project are an integral part of the City of Lakeland's "1998 Ten-Year Site Plan for Electrical Generating Facilities and Associated Transmission Lines," which Lakeland submitted to the Florida Public Service Commission in April 1998. The project schedule anticipates the start of commercial operation of the PCFB (McIntosh 4A) in 2003. In parallel with the first two years of operation of the PCFB will be the design, fabrication, and construction of the topped PCFB technology (McIntosh 4B), with a planned start of operation in 2005.

Negotiations continue between Lakeland and Foster Wheeler on the Engineer-Procure-Construct (EPC) proposal for the technology island.

Recent efforts focused on testing of the HGPFS, which is critical to system performance. Silicon carbide candle filters proved effective under conditions simulating those of the demonstration unit. At both 1,550 ºF and 1,400 ºF, the candle filters performed for over 1,000 hours at design levels without evidence of ash bridging or structural failure. Three new oxide-based candle filters showed promise as well. These will undergo further testing because of the potential for reduced cost and operation at higher temperatures.

Commercial Applications

The project serves as a stepping stone to move  PCFB technology to readiness for widespread commercial deployment in the post-2000 time frame. The project will include the first commercial applications of hot gas particulate cleanup and is one of the first to use a non-ruggedized gas turbine in a coal burning pressurized fluidized-bed application.

The combined-cycle PCFB system permits the combustion of a wide range of coals, including high-sulfur coals, and will compete with the pressurized bubbling-bed fluidized-bed system. PCFB can be used to repower or replace conventional power plants. Because of modular construction capability, PCFB generating plants permit utilities to add economical increments of capacity to match load growth or to repower plants using existing coal- and waste-handling equipment and steam turbines. Another advantage for repowering applications is the compactness of the process due to pressurized operation, which reduces space requirements per unit of energy generated.

The projected net heat rate for the 137-MWe (net) McIntosh Unit 4A system is approximately 9,480 Btu/kWh (based on HHV), which equates to over 36% efficiency.

Environmental attributes include in-situ sulfur removal of 95%, NO_x emissions less than 0.3 lb/10⁶ Btu, and particulate matter discharge less than 0.03 lb/10⁶ Btu. Solid waste will increase slightly as compared to conventional systems, but the dry material is readily disposable or potentially usable.

Contacts

Alfred M. Dodd, P.E., Project Director
(941) 499-6461
Tom Trickey, Project Manager
(941) 499-6477
Lakeland Electric
501 E. Lemon Street
Lakeland, FL 33801-5079
(941) 499-6344 (fax) 
adodd@city.lakeland.net  
ttric@city.lakeland.net 

George Lynch, DOE/HQ, (301) 903-9434 george.lynch@hq.doe.gov

Donald W. Geiling, P.E., NETL, (304) 285-4784 dgeili@netl.doe.gov