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Report of November 1999 Eastern Correctional Institution Cogeneration Facility Full-Scale Poultry Litter Test Burn

 

This report documents the methods employed and the results from a week-long test burn of poultry litter at the Eastern Correctional Institution Cogeneration Facility (ECICF) in Princess Anne, Maryland. The test burn occurred during the week of 8 November 1999 and was conducted as part of a comprehensive engineering and socioeconomic assessment of converting the existing ECICF to fire poultry litter as its primary fuel. The test burn, as well as the comprehensive engineering and socioeconomic assessment, were jointly sponsored by the Maryland Power Plant Research Program (PPRP) and the Maryland Environmental Service (MES), the operators of the ECICF.

Background

Since 1995, MES has been considering alternatives for expanding capacity at the ECICF because the existing boilers are not capable of meeting the electric and thermal demands of the ECI prison. Additionally, design and operating constraints of the boilers require high-quality wood chips (existing primary fuel), which are high in cost relative to lower-grade wood fuels. PPRP was engaged by MES to assist in the evaluation of alternate fuels as a means of reducing operating costs. A number of fuels were evaluated from 1995 through 1997 but none were determined to be economically feasible or sufficiently reliable. In the fall of 1997, coincident with pfiesteria outbreaks in portions of the Chesapeake Bay, MES requested that PPRP evaluate the use of poultry litter as a possible fuel. If feasible, the use of poultry litter as the primary fuel at ECICF would not only result in reduced operating costs for the ECICF, but its consumption as a fuel would contribute to a reduction in the amount of litter that is applied as a fertilizer on the lower Eastern Shore of Maryland, a practice that has been identified as having a probable link to the pfiesteria outbreaks.

Initially, MES and PPRP performed a preliminary feasibility study that focused on the availability and suitability of poultry litter as a fuel. Results of this study indicated that the physical and chemical characteristics (e.g., heat value and moisture content) of poultry litter are not significantly different than the respective values for wood chips. The initial study also determined that direct combustion with a spreader stoker fuel distribution system, like that which exists at the ECICF, would be the most appropriate technology for firing poultry litter. Based on these favorable preliminary findings, a more detailed, comprehensive engineering and socioeconomic assessment was performed over 1998 and 1999, including a full-scale poultry litter test burn at the ECICF.

Engineering and Socioeconomic Assessment

The comprehensive engineering and socioeconomic assessment determined that significant modifications to the existing ECICF boilers would be necessary to burn poultry litter. The cumulative capital cost for the modifications necessary to burn poultry litter was estimated as of May 1999 at approximately $6 million, with a 20-year life-cycle cost of slightly less than the life-cycle cost of continuing current operations (however, lesser modifications were identified during the study as a means to improve current operations and reduce life-cycle costs). Additionally, it was estimated that modifying the existing boilers and using poultry litter as fuel would consume approximately 54,000 tons of litter per year, which represents approximately 30% of the excess litter on the lower Eastern Shore. Since all of the engineering analyses and cost projections performed as part of the assessment were based on numerical models and "desk-top" studies, a test burn of poultry litter in one of the ECICF boilers was recommended to provide empirical data that could be used to validate many of the engineering and economic projections, or provide a basis for adjusting the study’s conclusions and recommendations, if necessary.

Test Burn

The test burn was performed over the week of 8 November 1999. Approximately 86 tons of cubed poultry litter were combusted, with a total firing time of 40 hours. All elements of the ECICF were tested during the test burn, including fuel handling systems, one of the two boilers, air emissions, and ash handling system. The test burn confirmed the need for the modifications previously identified in the "desk-top" studies, (i.e. approximately $6 million in capital). However, the test burn identified the need for other modifications not previously identified or only included as contingency items in the previous conversion cost estimate. Collectively, the additional modifications determined to be necessary as a result of the test burn could result in as much as a 30% increase in the cost to convert the ECICF to burn poultry litter. More important than the increased cost, however, is the uncertainty of whether the modified facility would perform reliably -- a paramount concern in light of the ECICF's role at the ECI prison. Specifically, the lead combustion engineer for the project and the grate manufacturer have indicated they would not support nor guarantee the proposed modification.


Above is the executive summary. The entire report (851KB) is available on-line in pdf format (you will need the Adobe Acrobat reader to view it.)

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This page was updated on December 8, 2000.