State-of-the-Art Biomass Cogeneration Facility: Operating Experience

摘要

The Okeelanta Power and Osceola Power biomass cogeneration facilities were the first large-scale bagasse/wood-fired cogeneration facilities ever constructed in the continental U.S. Because of its more extensive operating history, this paper will focus on the Okeelanta Power facility. The Okeelanta Power facility was designed and constructed as a 74.9-megawatt (MW) state-of-the-art power generating facility to provide steam to the adjacent sugar mill. The environmental benefit of the facility was significant in terms of total air emissions to the atmosphere, use of renewable resources for power generation, and use of state-of-the-art air pollution control equipment. A number of permitting issues were resolved prior to construction of the facility and enhancements were made to the facility design, such as the addition of a mercury control system, to facilitate approval of the project. After startup of the facility, several operational challenges were encountered due to inexperience with handling and burning of bagasse and wood from a variety of sources. This led to problems meeting certain air emissions limits, which required resolution with the regulatory agencies. In addition to these technical problems, a disagreement over the purchase power contract for the facility adversely impacted the ability of the facility to operate. This paper presents an overview and history of the facility, the air pollution control equipment is described, and air emissions test data from the facility are presented. The environmental benefit of the Okeelanta Power facility was significant in terms of total air emissions to the atmosphere, use of renewable resources for power generation, and use of state-of-the-art air pollution control equipment. A significant net reduction in emissions was projected to occur due to the shutdown of the older sugar mill boilers located at the adjacent sugar mill. A number of permitting issues were resolved prior to construction of the facility, and enhancements were made to the facility design, such as the addition of a mercury-control system, to facilitate approval of the project. The air pollution control equipment designed for the facility consisted of: an electrostatic precipitator (ESP) for control of particulate matter (PM) and heavy metals; a selective non-catalytic reduction (SNCR) system for nitrogen oxides (NOx) control; an activated carbon injection system for mercury control; good combustion practices for carbon monoxide (CO)/volatile organic compounds (VOC) control; and low-sulfur fuels for sulfur dioxide (SO2) control. After startup of the facility, a number of operational challenges were encountered due to inexperience with handling and burning of bagasse and wood from a variety of sources. This led to problems meeting certain air emissions limits, which required resolution with the regulatory agencies. Design changes and/or changes to emission limits were required to resolve many of these issues. In addition to these technical problems, a disagreement over the purchase power contract for the facility adversely impacted the ability of the facility to operate. This paper presents an overview and history of the facility, the air pollution control equipment is described, and air emissions test data from the facility are presented. A number of emission compliance tests have been performed on the Okeelanta Power boilers. These tests have been conducted while firing either bagasse or wood. Test results for all pollutants are summarized in this paper. The emission limits for the facility are also presented.