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Abstracts
Biomass Utilization
"Biomass Gasification Pilot Plant Study," A.H. Furman, S.G.Kimura, R.E. Ayala, and J.F. Joyce, EPA-600/R-93-170, September 1993.
Abstract
A gasification pilot program was carried out at the GE Research and Development
Center using two biomass feedstocks: bagasse pellets and wood chips. The object
of the testing was to determine the properties of biomass product gas and
its suitability as a fuel for gas-turbine-based power generation cycles. Gasification
of the feedstocks was performed at a feed rate of approximately one ton per
hour, using the GE pressurized, fixed-bed gasifier and a single stage of cyclone
particulate removal, operating at 1000° F. The biomass product gas was
analyzed for chemical composition, particulate loading, fuel-bound nitrogen
(FBN) levels, and sulfur and alkali metal content.
Both feedstocks gasified easily. The composition and heating value of the biomass product gas were compatible with gas turbine combustion requirements. However, the particulate removal performance of the pilot facility single-stage cyclone did not meet turbine specifications. In addition, alkali metal compounds in the particulate matter (at 1000° F) carried over from the gasifier exceeded turbine limits. Improved particulate removal technology, designed specifically for biomass feedstock characteristics, could meet turbine requirements for both particulate and alkali loading. FBN compounds were also measured since they can be converted to NOx during combustion in a gas turbine. Since this conversion is highly dependent on gas turbine combustor design, no firm conclusions regarding NOx production can be reached without actual combustion testing.
This report was submitted in fulfillment of Vermont Department of Public Service Contract 0938222 covering work performed by General Electric Corporate Research and Development under the partial sponsorship of the U.S. Environmental Protection Agency under cooperative agreement CR 817675. This report covers a period from April 1991 until March 1993, and the work was completed as of July 1992. The EPA Project Officer for the study was Carol R. Purvis.
Emissions Inventories
"Data Attribute Rating System," Lee L. Beck and Darcy Wilson, paper presented in Raleigh, NC, on October 28, 1997, Air and Waste Management Association (AWMA) conference on "The Emissions Inventory: Planning for the Future."
Abstract
The U.S. Environmental Protection Agency (EPA) has developed the Data Attribute
Rating System (DARS) to assist in evaluating data associated with emission
inventories. The system disaggregates emission inventories into emission factors
and activity rate, then assigns a numerical score to each of these two components.
Each score is based on what is known about the factor and activity parameters,
such as the specificity to the source category, the spatial (geographical)
congruity, the measurement or estimation techniques employed, and the temporal
congruity. The resulting emission factor and activity rate scores are combined
to arrive at an overall confidence rating for the inventory. Though numerical
values are generated, the system is only semiquantitative. However, DARS is
believed to be a useful tool and may provide more information about inventories
than the usual qualitative grading procedures (e.g., A through E) used to
characterize data (e.g., in EPA’s Compilation of Air Pollutant Emission
Factors). The individual rating components are presented, and the attribute
evaluation techniques are discussed. The development rationale and history
are described, and recent enhancements such as DARS software are presented.
Mitigation Software
"Data Attribute Rating System," Lee L. Beck and Darcy Wilson, paper presented in Raleigh, NC, on October 28, 1997, Air and Waste Management Association (AWMA) conference on "The Emissions Inventory: Planning for the Future."
Abstract
The U.S. Environmental Protection Agency (EPA) has developed the Data Attribute
Rating System (DARS) to assist in evaluating data associated with emission
inventories. The system disaggregates emission inventories into emission factors
and activity rate, then assigns a numerical score to each of these two components.
Each score is based on what is known about the factor and activity parameters,
such as the specificity to the source category, the spatial (geographical)
congruity, the measurement or estimation techniques employed, and the temporal
congruity. The resulting emission factor and activity rate scores are combined
to arrive at an overall confidence rating for the inventory. Though numerical
values are generated, the system is only semiquantitative. However, DARS is
believed to be a useful tool and may provide more information about inventories
than the usual qualitative grading procedures (e.g., A through E) used to
characterize data (e.g., in EPA’s Compilation of Air Pollutant Emission
Factors). The individual rating components are presented, and the attribute
evaluation techniques are discussed. The development rationale and history
are described, and recent enhancements such as DARS software are presented.
Nitrous Oxide Emissions
"Characterization of Nitrous Oxide Emission Sources," EPA-600/R-95-105, July 1995
Abstract
Nitrous oxide (N2O) is both a greenhouse gas and a precursor of nitric oxide (NO) which destroys stratospheric ozone. This study presents a global N2O inventory based on re-evaluation of previous estimates and additions of previously uninventoried source categories. The best estimate of anthropogenic N2O is 5.7 Tg N2O/yr, which is still much lower than natural
source emissions. Much uncertainty remains about estimates for many source categories. Inadequate data are available for some categories, while others are limited by a lack of reliable functional models of factors affecting emission rates.